DIY Two-Stroke Engine Construction Methods

[durabol[_2_]]

The two main methods for homebuilt construction would be casting vs.
machining or some combination of both (probably the best option).
Forging probably isn't appropriate for home construction (either the
piston or connecting rod).

One method I have thought of is to produce a wax model of the engine
with molds (to a fairly high tolerance to minimize machining) which is
then cast using lost wax casting techniques. I planned to have an
integral cylinder head/cylinder/half the crank case (this is for an
opposed style engine). The only bolts would be to bolt the two halves
together.

A completely machined engine would need a large block of aluminium to
start with which I'm not sure how practical that would be. Perhaps
lost foam casting could be used as a general model of the engine was
made in foam and then cast and the resulting casting could be
machined.

Brock

[Jim Wilkins]

On Mar 10, 1:45*am, durabol > wrote:
> ...
> One method I have thought of is to produce a wax model of the engine
> with molds (to a fairly high tolerance to minimize machining) ...>
> Brock

What machine tools do you have?

Some WW1 engine cylinders were machined from SOLID steel forgings.
Casting can easily have internal voids unless well designed, because
the metal shrinks as it solidifies inwards. Aluminum is easy enough to
melt that you could cast a simple shape and then test it for strength
or cut it apart.

Or you could make a lawnmower engine and see how durable it is.

jsw

[basilisk]

"durabol" > wrote in message
...
> The two main methods for homebuilt construction would be casting vs.
> machining or some combination of both (probably the best option).
> Forging probably isn't appropriate for home construction (either the
> piston or connecting rod).
>
> One method I have thought of is to produce a wax model of the engine
> with molds (to a fairly high tolerance to minimize machining) which is
> then cast using lost wax casting techniques. I planned to have an
> integral cylinder head/cylinder/half the crank case (this is for an
> opposed style engine). The only bolts would be to bolt the two halves
> together.

Most two strokes are single cylinder that rely on crankcase pumping
action to move the fuel/air mixture, if you go to a multiple opposed
cylinders, you will have to provide a slave cylinder or roots type blower
to move the air.

basilisk

[Lloyd E. Sponenburgh]

"basilisk" > fired this volley in news:J4Nln.198564
:

> you will have to provide a slave cylinder or roots type blower
> to move the air.
>
>

Some variants use a cylinder skirt with reed valving.

LLoyd

[Lloyd E. Sponenburgh]

"Lloyd E. Sponenburgh" <lloydspinsidemindspring.com> fired this volley in
. 3.70:

> "basilisk" > fired this volley in
news:J4Nln.198564
> :
>
>> you will have to provide a slave cylinder or roots type blower
>> to move the air.
>>
>>
>
> Some variants use a cylinder skirt with reed valving.
>
> LLoyd
>

That didn't come out right... They use a "divider" or partition of sorts
at the journal between con-rods, and reed valving for intake on each side
of the divider. The "skirt" just extends across the whole crankcase.

LLoyd

[basilisk]

"Lloyd E. Sponenburgh" <lloydspinsidemindspring.com> wrote in message
. 3.70...
> "basilisk" > fired this volley in news:J4Nln.198564
> :
>
>> you will have to provide a slave cylinder or roots type blower
>> to move the air.
>>
>>
>
> Some variants use a cylinder skirt with reed valving.
>
> LLoyd

You're right, I didn't really consider that before posting.

I supposed it could be worked out but that looks hard to
do in a completely bottom assembled engine, just my 2 cents worth,
I'm not an engine specialist.

basilisk

[[email protected]]

In article >, "basilisk" > wrote:
>
>"durabol" > wrote in message
...
>> The two main methods for homebuilt construction would be casting vs.
>> machining or some combination of both (probably the best option).
>> Forging probably isn't appropriate for home construction (either the
>> piston or connecting rod).
>>
>> One method I have thought of is to produce a wax model of the engine
>> with molds (to a fairly high tolerance to minimize machining) which is
>> then cast using lost wax casting techniques. I planned to have an
>> integral cylinder head/cylinder/half the crank case (this is for an
>> opposed style engine). The only bolts would be to bolt the two halves
>> together.
>
>Most two strokes are single cylinder that rely on crankcase pumping
>action to move the fuel/air mixture, if you go to a multiple opposed
>cylinders, you will have to provide a slave cylinder or roots type blower
>to move the air.
>
>basilisk
>
>
my kawai h2 uses reeds and i believe has opposed cylinders. it ain't no
lawnmower.....

[[email protected]]

In article >, "basilisk" > wrote:
>
>"Lloyd E. Sponenburgh" <lloydspinsidemindspring.com> wrote in message
. 3.70...
>> "basilisk" > fired this volley in news:J4Nln.198564
>> :
>>
>>> you will have to provide a slave cylinder or roots type blower
>>> to move the air.
>>>
>>>
>>
>> Some variants use a cylinder skirt with reed valving.
>>
>> LLoyd
>
>You're right, I didn't really consider that before posting.
>
>I supposed it could be worked out but that looks hard to
>do in a completely bottom assembled engine, just my 2 cents worth,
>I'm not an engine specialist.
>
>basilisk
>
>
it's not so hard, it just costs a bit more. but it adds a lot of grunt.
the 750 i have puts out almost 90hp. dragster h2's running exotic fuels have
been dynoed at over 400hp!. they need to be rebuilt often, but what drag motor
doesn't.
the quest for hp is expensive but doable. honda built a tt racer that got 18hp
out of 50cc! the 8 speed gearbox got it up to 100mph.
read about the mv augusta racers, you wouldn't believe me.

[Tim Wescott]

durabol wrote:
> The two main methods for homebuilt construction would be casting vs.
> machining or some combination of both (probably the best option).
> Forging probably isn't appropriate for home construction (either the
> piston or connecting rod).
>
> One method I have thought of is to produce a wax model of the engine
> with molds (to a fairly high tolerance to minimize machining) which is
> then cast using lost wax casting techniques. I planned to have an
> integral cylinder head/cylinder/half the crank case (this is for an
> opposed style engine). The only bolts would be to bolt the two halves
> together.
>
> A completely machined engine would need a large block of aluminium to
> start with which I'm not sure how practical that would be. Perhaps
> lost foam casting could be used as a general model of the engine was
> made in foam and then cast and the resulting casting could be
> machined.

Don't sneer at sand castings, particularly for aluminum parts. Rods and
pistons can be made from billet, or can be purchased from racing parts
suppliers -- racers often customize these parts, so if you can find an
engine with e.g. a similar rod you can order one from Carillo or whoever
"yea, I want a Honda XYZ rod, but make it 5" center to center and make
the big end take a bearing from a Kumatsu 30HP diesel".

For an absolutely "I'm only gonna build one ever" engine you could
fabricate the rough parts by welding or brazing, then stress relieve,
then machine. This is, I believe, how railway locomotive and ship
engines are often built, and I believe that there were automotive
engines built this way, too.

You're building an aero engine, right? And it's going to be air cooled,
right? If so, the advantages of separate cylinder assemblies probably
outweighs the disadvantages of trying to build a monoblock engine.
Trash a cylinder on a monoblock engine and you have to do a complete
rebuild. Trash one cylinder on an assembled engine and you just have to
replace one part.

Another of the advantages of separate cylinders is that you can build a
one-cylinder "research engine" to get the myriad of details worked out.
Then when you like the porting and combustion chamber shape and
cooling fin layout and piston design and ring lands and cylinder finish,
and etc., you can build the multi-cylinder engine of your choice.

--
Tim Wescott
Control system and signal processing consulting
www.wescottdesign.com

[Jim Stewart]

durabol wrote:
> The two main methods for homebuilt construction would be casting vs.
> machining or some combination of both (probably the best option).
> Forging probably isn't appropriate for home construction (either the
> piston or connecting rod).
>
> One method I have thought of is to produce a wax model of the engine
> with molds (to a fairly high tolerance to minimize machining) which is
> then cast using lost wax casting techniques. I planned to have an
> integral cylinder head/cylinder/half the crank case (this is for an
> opposed style engine). The only bolts would be to bolt the two halves
> together.
>
> A completely machined engine would need a large block of aluminium to
> start with which I'm not sure how practical that would be. Perhaps
> lost foam casting could be used as a general model of the engine was
> made in foam and then cast and the resulting casting could be
> machined.

I went back and read your first post to try to
get the big picture here. So what I think you
are saying is that you want to build an engine
that will be roughly equivalent to a Rotax 2-stroke
ultralight engine. I think the best advise I
could give you is don't. Despite the fact that
the Rotax engines are meticulously designed and
built, they still fail and have a 300 hour rebuild
interval. They have exotic coatings and metallurgy
to get the reliability that they have. There's no
way you'll even come close to their performance and
reliability in you garage.

Now if you want to build an engine, that's fine. If
you want to talk about building an engine, that's
fine too. I just have to say that you're taking
on a project with very, very small prospects of working
and a real steep downside if it fails in the air.

If you're interested in the design of the Rotax
engines, you can download the manuals here:

http://www.rotax-owner.com/index.php?option=com_content&view=article&id=108&Itemid=25

The line drawings of the engine, piston and cylinder
might be of interest.

[Tim Wescott]

Jim Stewart wrote:
> durabol wrote:
>> The two main methods for homebuilt construction would be casting vs.
>> machining or some combination of both (probably the best option).
>> Forging probably isn't appropriate for home construction (either the
>> piston or connecting rod).
>>
>> One method I have thought of is to produce a wax model of the engine
>> with molds (to a fairly high tolerance to minimize machining) which is
>> then cast using lost wax casting techniques. I planned to have an
>> integral cylinder head/cylinder/half the crank case (this is for an
>> opposed style engine). The only bolts would be to bolt the two halves
>> together.
>>
>> A completely machined engine would need a large block of aluminium to
>> start with which I'm not sure how practical that would be. Perhaps
>> lost foam casting could be used as a general model of the engine was
>> made in foam and then cast and the resulting casting could be
>> machined.
>
> I went back and read your first post to try to
> get the big picture here. So what I think you
> are saying is that you want to build an engine
> that will be roughly equivalent to a Rotax 2-stroke
> ultralight engine. I think the best advise I
> could give you is don't. Despite the fact that
> the Rotax engines are meticulously designed and
> built, they still fail and have a 300 hour rebuild
> interval. They have exotic coatings and metallurgy
> to get the reliability that they have. There's no
> way you'll even come close to their performance and
> reliability in you garage.

But he wants the performance and reliability in the air, not his garage!!!

(sorry, couldn't resist).

> Now if you want to build an engine, that's fine. If
> you want to talk about building an engine, that's
> fine too. I just have to say that you're taking
> on a project with very, very small prospects of working
> and a real steep downside if it fails in the air.

You could probably make some weight/reliability trades, though -- for
one example, use iron cylinder liners and conventional steel rings
instead of sooper-dooper nitrited aluminum fancy-pants coatings.

And always fly within an easy glide of a landing strip...

--
Tim Wescott
Control system and signal processing consulting
www.wescottdesign.com

[Jim Stewart]

Tim Wescott wrote:
> Jim Stewart wrote:
>> durabol wrote:
>>> The two main methods for homebuilt construction would be casting vs.
>>> machining or some combination of both (probably the best option).
>>> Forging probably isn't appropriate for home construction (either the
>>> piston or connecting rod).
>>>
>>> One method I have thought of is to produce a wax model of the engine
>>> with molds (to a fairly high tolerance to minimize machining) which is
>>> then cast using lost wax casting techniques. I planned to have an
>>> integral cylinder head/cylinder/half the crank case (this is for an
>>> opposed style engine). The only bolts would be to bolt the two halves
>>> together.
>>>
>>> A completely machined engine would need a large block of aluminium to
>>> start with which I'm not sure how practical that would be. Perhaps
>>> lost foam casting could be used as a general model of the engine was
>>> made in foam and then cast and the resulting casting could be
>>> machined.
>>
>> I went back and read your first post to try to
>> get the big picture here. So what I think you
>> are saying is that you want to build an engine
>> that will be roughly equivalent to a Rotax 2-stroke
>> ultralight engine. I think the best advise I
>> could give you is don't. Despite the fact that
>> the Rotax engines are meticulously designed and
>> built, they still fail and have a 300 hour rebuild
>> interval. They have exotic coatings and metallurgy
>> to get the reliability that they have. There's no
>> way you'll even come close to their performance and
>> reliability in you garage.
>
> But he wants the performance and reliability in the air, not his garage!!!
>
> (sorry, couldn't resist).

Good point nonetheless...

>> Now if you want to build an engine, that's fine. If
>> you want to talk about building an engine, that's
>> fine too. I just have to say that you're taking
>> on a project with very, very small prospects of working
>> and a real steep downside if it fails in the air.
>
> You could probably make some weight/reliability trades, though -- for
> one example, use iron cylinder liners and conventional steel rings
> instead of sooper-dooper nitrited aluminum fancy-pants coatings.
>
> And always fly within an easy glide of a landing strip...

That's a given. The problem is an engine out on takeoff
climb. With an ultralight, it's very difficult to
impossible to get the nose down and airspeed up fast enough
to avoid a stall. Of course, you can (and should) carry a
rocket-deployed chute on your ultralight, but it's bad
form to have to depend on one.

[Tim Wescott]

Jim Stewart wrote:
> Tim Wescott wrote:
>> Jim Stewart wrote:
>>> durabol wrote:
>>>> The two main methods for homebuilt construction would be casting vs.
>>>> machining or some combination of both (probably the best option).
>>>> Forging probably isn't appropriate for home construction (either the
>>>> piston or connecting rod).
>>>>
>>>> One method I have thought of is to produce a wax model of the engine
>>>> with molds (to a fairly high tolerance to minimize machining) which is
>>>> then cast using lost wax casting techniques. I planned to have an
>>>> integral cylinder head/cylinder/half the crank case (this is for an
>>>> opposed style engine). The only bolts would be to bolt the two halves
>>>> together.
>>>>
>>>> A completely machined engine would need a large block of aluminium to
>>>> start with which I'm not sure how practical that would be. Perhaps
>>>> lost foam casting could be used as a general model of the engine was
>>>> made in foam and then cast and the resulting casting could be
>>>> machined.
>>>
>>> I went back and read your first post to try to
>>> get the big picture here. So what I think you
>>> are saying is that you want to build an engine
>>> that will be roughly equivalent to a Rotax 2-stroke
>>> ultralight engine. I think the best advise I
>>> could give you is don't. Despite the fact that
>>> the Rotax engines are meticulously designed and
>>> built, they still fail and have a 300 hour rebuild
>>> interval. They have exotic coatings and metallurgy
>>> to get the reliability that they have. There's no
>>> way you'll even come close to their performance and
>>> reliability in you garage.
>>
>> But he wants the performance and reliability in the air, not his
>> garage!!!
>>
>> (sorry, couldn't resist).
>
> Good point nonetheless...
>
>>> Now if you want to build an engine, that's fine. If
>>> you want to talk about building an engine, that's
>>> fine too. I just have to say that you're taking
>>> on a project with very, very small prospects of working
>>> and a real steep downside if it fails in the air.
>>
>> You could probably make some weight/reliability trades, though -- for
>> one example, use iron cylinder liners and conventional steel rings
>> instead of sooper-dooper nitrited aluminum fancy-pants coatings.
>>
>> And always fly within an easy glide of a landing strip...
>
> That's a given. The problem is an engine out on takeoff
> climb. With an ultralight, it's very difficult to
> impossible to get the nose down and airspeed up fast enough
> to avoid a stall.

I did not know this -- I fly models, not ultralights. It's scary to
contemplate, though. I would consider a model that can't recover from a
sudden engine-out event to be more than a bit of a turd; I wouldn't want
to get _close_ to a full scale aircraft with that 'feature'.

Surely there are ultralights that don't exhibit this problem!

Is it a consequence of the draggy airframe on the usual ultralight? Or
are you thinking of the flavor of ultralights where you steer by
shifting weight, rather than with a movable elevator? Is there anything
you can do to mitigate the risk during takeoff, i.e. can you trade
climbing performance for safety by keeping the nose down and flying a
bit hotter?

> Of course, you can (and should) carry a
> rocket-deployed chute on your ultralight, but it's bad
> form to have to depend on one.

Or an ejection seat...

--
Tim Wescott
Control system and signal processing consulting
www.wescottdesign.com

[Tim Wescott]

Jim Stewart wrote:
> durabol wrote:
>> The two main methods for homebuilt construction would be casting vs.
>> machining or some combination of both (probably the best option).
>> Forging probably isn't appropriate for home construction (either the
>> piston or connecting rod).
>>
>> One method I have thought of is to produce a wax model of the engine
>> with molds (to a fairly high tolerance to minimize machining) which is
>> then cast using lost wax casting techniques. I planned to have an
>> integral cylinder head/cylinder/half the crank case (this is for an
>> opposed style engine). The only bolts would be to bolt the two halves
>> together.
>>
>> A completely machined engine would need a large block of aluminium to
>> start with which I'm not sure how practical that would be. Perhaps
>> lost foam casting could be used as a general model of the engine was
>> made in foam and then cast and the resulting casting could be
>> machined.
>
> I went back and read your first post to try to
> get the big picture here. So what I think you
> are saying is that you want to build an engine
> that will be roughly equivalent to a Rotax 2-stroke
> ultralight engine. I think the best advise I
> could give you is don't. Despite the fact that
> the Rotax engines are meticulously designed and
> built, they still fail and have a 300 hour rebuild
> interval. They have exotic coatings and metallurgy
> to get the reliability that they have. There's no
> way you'll even come close to their performance and
> reliability in you garage.
>
> Now if you want to build an engine, that's fine. If
> you want to talk about building an engine, that's
> fine too. I just have to say that you're taking
> on a project with very, very small prospects of working
> and a real steep downside if it fails in the air.
>
> If you're interested in the design of the Rotax
> engines, you can download the manuals here:
>
> http://www.rotax-owner.com/index.php?option=com_content&view=article&id=108&Itemid=25
>
>
> The line drawings of the engine, piston and cylinder
> might be of interest.

I should mention at this juncture, that any time you say "never do that,
it's too hard for an individual" you're citing a rule that -- if applied
recursively -- is telling your audience "never do anything".

Raking over all possible difficulties so that someone can take them into
account, however, is more than a little bit helpful.

--
Tim Wescott
Control system and signal processing consulting
www.wescottdesign.com

[TonyW]

On 3/10/2010 7:46 AM, wrote:

> it's not so hard, it just costs a bit more. but it adds a lot of grunt.
> the 750 i have puts out almost 90hp. dragster h2's running exotic fuels have
> been dynoed at over 400hp!. they need to be rebuilt often, but what drag motor
> doesn't.
> the quest for hp is expensive but doable. honda built a tt racer that got 18hp
> out of 50cc! the 8 speed gearbox got it up to 100mph.
> read about the mv augusta racers, you wouldn't believe me.

Suzuki built but never raced a 3 cylinder 50cc engine that was rated at
the highest output per liter on record for use with pump gas. However
to get to one liter it would have 60 cylinders...

Tony

[[email protected]]

In article >, TonyW > wrote:
>On 3/10/2010 7:46 AM, wrote:
>
>> it's not so hard, it just costs a bit more. but it adds a lot of grunt.
>> the 750 i have puts out almost 90hp. dragster h2's running exotic fuels have
>> been dynoed at over 400hp!. they need to be rebuilt often, but what drag
> motor
>> doesn't.
>> the quest for hp is expensive but doable. honda built a tt racer that got
> 18hp
>> out of 50cc! the 8 speed gearbox got it up to 100mph.
>> read about the mv augusta racers, you wouldn't believe me.
>
>Suzuki built but never raced a 3 cylinder 50cc engine that was rated at
>the highest output per liter on record for use with pump gas. However
>to get to one liter it would have 60 cylinders...
>
>Tony

yeah, with enough money and resources, pigs will fly.

[Jim Stewart]

Tim Wescott wrote:
> Jim Stewart wrote:
>> durabol wrote:
>>> The two main methods for homebuilt construction would be casting vs.
>>> machining or some combination of both (probably the best option).
>>> Forging probably isn't appropriate for home construction (either the
>>> piston or connecting rod).
>>>
>>> One method I have thought of is to produce a wax model of the engine
>>> with molds (to a fairly high tolerance to minimize machining) which is
>>> then cast using lost wax casting techniques. I planned to have an
>>> integral cylinder head/cylinder/half the crank case (this is for an
>>> opposed style engine). The only bolts would be to bolt the two halves
>>> together.
>>>
>>> A completely machined engine would need a large block of aluminium to
>>> start with which I'm not sure how practical that would be. Perhaps
>>> lost foam casting could be used as a general model of the engine was
>>> made in foam and then cast and the resulting casting could be
>>> machined.
>>
>> I went back and read your first post to try to
>> get the big picture here. So what I think you
>> are saying is that you want to build an engine
>> that will be roughly equivalent to a Rotax 2-stroke
>> ultralight engine. I think the best advise I
>> could give you is don't. Despite the fact that
>> the Rotax engines are meticulously designed and
>> built, they still fail and have a 300 hour rebuild
>> interval. They have exotic coatings and metallurgy
>> to get the reliability that they have. There's no
>> way you'll even come close to their performance and
>> reliability in you garage.
>>
>> Now if you want to build an engine, that's fine. If
>> you want to talk about building an engine, that's
>> fine too. I just have to say that you're taking
>> on a project with very, very small prospects of working
>> and a real steep downside if it fails in the air.
>>
>> If you're interested in the design of the Rotax
>> engines, you can download the manuals here:
>>
>> http://www.rotax-owner.com/index.php?option=com_content&view=article&id=108&Itemid=25
>>
>>
>> The line drawings of the engine, piston and cylinder
>> might be of interest.
>
> I should mention at this juncture, that any time you say "never do that,
> it's too hard for an individual" you're citing a rule that -- if applied
> recursively -- is telling your audience "never do anything".

Agreed. Just the same, there are little steps and
big stumbles. I would offer much encouragement if
the goal was to build and fly a small 2-stroke on
a control-line model. Not much at stake and a good
prospect for succeeding. The last issue of Model
Engine Builder had plans..

http://www.modelenginebuilder.com/elmwood.htm

OTOH, I just finished reading the ATSM consensus
standards for light sport aircraft engine design.
Not gonna happen in a garage.

> Raking over all possible difficulties so that someone can take them into
> account, however, is more than a little bit helpful.

[Jim Stewart]

Tim Wescott wrote:

>>> And always fly within an easy glide of a landing strip...
>>
>> That's a given. The problem is an engine out on takeoff
>> climb. With an ultralight, it's very difficult to
>> impossible to get the nose down and airspeed up fast enough
>> to avoid a stall.
>
> I did not know this -- I fly models, not ultralights. It's scary to
> contemplate, though. I would consider a model that can't recover from a
> sudden engine-out event to be more than a bit of a turd; I wouldn't want
> to get _close_ to a full scale aircraft with that 'feature'.

I think all engine-driven aircraft have a window
of vulnerability on takeoff. Most general aviation
planes can't return to the runway straight ahead
and successfully land if they are higher than 200'
and can't turn around to return to the field unless
they are higher than 500'. Consider that the headwind
that you took off into is now a tailwind and you
can see how badly your day gets.

That's why takeoffs are *always* full throttle and
best rate of climb. You spend the least amount
of time getting through that zone.

> Surely there are ultralights that don't exhibit this problem!

Don't know. I was told that by someone whose knowledge
and experience were much greater than mine.

> Is it a consequence of the draggy airframe on the usual ultralight? Or
> are you thinking of the flavor of ultralights where you steer by
> shifting weight, rather than with a movable elevator? Is there anything
> you can do to mitigate the risk during takeoff, i.e. can you trade
> climbing performance for safety by keeping the nose down and flying a
> bit hotter?

Don't know for sure. I think the combination of
light weight and high drag bleeds off the airspeed
so quickly that you loose elevator authority
before you can put it to use.

>> Of course, you can (and should) carry a
>> rocket-deployed chute on your ultralight, but it's bad
>> form to have to depend on one.
>
> Or an ejection seat...
>

[Morgans[_2_]]

"basilisk" > wrote

> Most two strokes are single cylinder that rely on crankcase pumping
> action to move the fuel/air mixture, if you go to a multiple opposed
> cylinders, you will have to provide a slave cylinder or roots type blower
> to move the air.

Or you have each pair of cylinders and pistons moving outward and firing at
the same time, and have each opposing pair separated from the other opposing
pairs. It would still pump like regular single lung 2 strokes, then.

A 6 cylinder opposing pair would be an interesting 2 stroke engine. 3 power
pulses per revolution, and two pistons firing on each pulse. This concept
could mean that each pair could be designed basically identical, and bolted
together. You could add as many pairs as you wanted, to get the power
output you want. 6, or 8 or 10 cylinders! Cool! A 10 cylinder engine
should be as smooth as a turbine engine, but probably with the fuel flow to
match! ;-)

You could keep the cylinder sizes very small, and the engine very narrow but
long. This might be a concept to explore, I think.

If you wanted, you could have each pair rotated a little, somewhat like a
multi layer radial engine, for cooling mainly. It would probably make it
more complex than the benefits would justify.
--
Jim in NC

[Jim Logajan]

Tim Wescott > wrote:
> Jim Stewart wrote:
>> Tim Wescott wrote:
>>> And always fly within an easy glide of a landing strip...
>>
>> That's a given. The problem is an engine out on takeoff
>> climb. With an ultralight, it's very difficult to
>> impossible to get the nose down and airspeed up fast enough
>> to avoid a stall.
>
....
> Surely there are ultralights that don't exhibit this problem!

There are: Powered parachutes.[1]

Almost certainly other types of ultralights don't exhibit that issue
either, too. (Discounting even ultralight airships.) I suspect Jim
Stewart's source was generalizing a wee bit too much.

[1] http://www.quakerstatepoweredparachutes.com/engine_failure.htm

[Jim Stewart]

Jim Logajan wrote:
> Tim Wescott > wrote:
>> Jim Stewart wrote:
>>> Tim Wescott wrote:
>>>> And always fly within an easy glide of a landing strip...
>>> That's a given. The problem is an engine out on takeoff
>>> climb. With an ultralight, it's very difficult to
>>> impossible to get the nose down and airspeed up fast enough
>>> to avoid a stall.
> ...
>> Surely there are ultralights that don't exhibit this problem!
>
> There are: Powered parachutes.[1]
>
> Almost certainly other types of ultralights don't exhibit that issue
> either, too. (Discounting even ultralight airships.) I suspect Jim
> Stewart's source was generalizing a wee bit too much.
>
> [1] http://www.quakerstatepoweredparachutes.com/engine_failure.htm

From your link...

"Turns increase sink rate which in turn increase broken bone rate."

Ouch.

[Jim Wilkins]

On Mar 10, 5:50*pm, Jim Logajan > wrote:
> Tim Wescott > wrote:
> > Jim Stewart wrote:
> >> That's a given. *The problem is an engine out on takeoff
> >> climb. *With an ultralight, it's very difficult to
> >> impossible to get the nose down and airspeed up fast enough
> >> to avoid a stall. *
>
> ...
> > Surely there are ultralights that don't exhibit this problem!
>
> There are: Powered parachutes.[1]

Engine failure at takeoff has claimed a lot of aces and test pilots:
http://en.wikipedia.org/wiki/Richard_Bong
http://en.wikipedia.org/wiki/James_McCudden

jsw

[cavelamb[_2_]]

Jim Stewart wrote:
> Tim Wescott wrote:
>
>> Is it a consequence of the draggy airframe on the usual ultralight?
>> Or are you thinking of the flavor of ultralights where you steer by
>> shifting weight, rather than with a movable elevator? Is there
>> anything you can do to mitigate the risk during takeoff, i.e. can you
>> trade climbing performance for safety by keeping the nose down and
>> flying a bit hotter?
>
> Don't know for sure. I think the combination of
> light weight and high drag bleeds off the airspeed
> so quickly that you loose elevator authority
> before you can put it to use.

Not really.
Low and slow U.S. aircraft of this kind usually have larger tail surfaces
and excellent control authority (at least in pitch) well below stall speed.

It's not like you stall and fall.
Most of them won't really stall at all.

But you can pick up a rather impressive sink rate!







--

Richard Lamb
http://www.home.earthlink.net/~cavelamb/

[[email protected]]

On Wed, 10 Mar 2010 07:24:54 -0600, "basilisk" >
wrote:

>
>"durabol" > wrote in message
...
>> The two main methods for homebuilt construction would be casting vs.
>> machining or some combination of both (probably the best option).
>> Forging probably isn't appropriate for home construction (either the
>> piston or connecting rod).
>>
>> One method I have thought of is to produce a wax model of the engine
>> with molds (to a fairly high tolerance to minimize machining) which is
>> then cast using lost wax casting techniques. I planned to have an
>> integral cylinder head/cylinder/half the crank case (this is for an
>> opposed style engine). The only bolts would be to bolt the two halves
>> together.
>
>Most two strokes are single cylinder that rely on crankcase pumping
>action to move the fuel/air mixture, if you go to a multiple opposed
>cylinders, you will have to provide a slave cylinder or roots type blower
>to move the air.
>
>basilisk

Or do like every 2 stroke multi-cyl engine in the past, and devide the
crankcase - basicaly X number of single cyl engines in a row.
>

[Jim Wilkins]

On Mar 10, 12:37*pm, Tim Wescott > wrote:
> ...
> Trash a cylinder on a monoblock engine and you have to do a complete
> rebuild. *Trash one cylinder on an assembled engine and you just have to
> replace one part.....
> Tim Wescott

Like this:
http://picasaweb.google.com/KB1DAL/Temporary#5256374948163130882
That's the right inboard engine of the B-17 "909", at an airshow in
Nashua NH. The cylinder cracked and they had to fix it to get home.

I happened to be standing under the wing when they set up the ladder
and made myself useful by taking the cowling pieces as they handed
them down, so by the time security roped off the area I looked like I
belonged there. Eventually the rest of the crew wandered off, leaving
just me assisting the crew chief to disassemble the head and fasten it
onto the good cylinder, then turn the prop while he set the valves. My
hands were too dirty to hold the camera most of the time.

Some day I'm going to make a model radial engine. First I might do a
pocket-sized one with valves timed to compress or run on air.

jsw

[Rufus]

durabol wrote:
> The two main methods for homebuilt construction would be casting vs.
> machining or some combination of both (probably the best option).
> Forging probably isn't appropriate for home construction (either the
> piston or connecting rod).
>
> One method I have thought of is to produce a wax model of the engine
> with molds (to a fairly high tolerance to minimize machining) which is
> then cast using lost wax casting techniques. I planned to have an
> integral cylinder head/cylinder/half the crank case (this is for an
> opposed style engine). The only bolts would be to bolt the two halves
> together.
>

As someone whom has done lost wax casting, I wouldn't recommend doing
that for something I was going to bet my life on...not without investing
LARGE amounts of capital in equipment - a centrifugal or pressure
injection foundry...sand casting (which I've also done) is a far better
alternative for casting a raw engine casing. Make a durable wooden
master model, preferably of a hardwood.

In any event, you're still going to have to sleeve the cylinders with
some alloy of machined, durable steel - which will have to be hardened
and polished in some way and interference fit into the block or stud.
And you need to match coefficients of thermal expansion when choosing
your materials in order to keep it all tight - same goes for choosing
and tolerancing your bolts and every other component in direct
contact...which means you also need to do some thermal analysis and
figure out how hot, as well as how, your engine is going to run...

> A completely machined engine would need a large block of aluminium to
> start with which I'm not sure how practical that would be. Perhaps
> lost foam casting could be used as a general model of the engine was
> made in foam and then cast and the resulting casting could be
> machined.
>
> Brock

Again - big investment in big machines to insure uniformity of the
casting...which will kill the project (and the pilot) if you screw it
up. Hot spots, porosity, voids...not that simple. Best way to
spot/find/quality check castings involve die penetrant or x-ray.

Also - don't overlook the fact that you are going to have to heat treat,
case harden, or otherwise machine or post-work any part you produce
depending on choice and application of materials...I don't know what
kind of tools and resources the OP has at hand, but if he's starting
from scratch he better be prepared to spend the amount of money he'd
spend on a mid-size car in tooling just to get started with such a
project...make it a large luxury car, now that I think about it...

The far easier (and safer) alternative is to modify an existing engine -
like a motorcycle engine - strip it down and just build the parts and
accessories required to make it turn a prop. And along the way one can
also machine it's component parts down to lighten it...run it on the
ground, if it breaks, you know you went too far.

--
- Rufus (pilot, engineer, jeweler, model builder...yadda, yadda...)

[Rufus]

basilisk wrote:
> "Lloyd E. Sponenburgh" <lloydspinsidemindspring.com> wrote in message
> . 3.70...
>> "basilisk" > fired this volley in news:J4Nln.198564
>> :
>>
>>> you will have to provide a slave cylinder or roots type blower
>>> to move the air.
>>>
>>>
>> Some variants use a cylinder skirt with reed valving.
>>
>> LLoyd
>
> You're right, I didn't really consider that before posting.
>
> I supposed it could be worked out but that looks hard to
> do in a completely bottom assembled engine, just my 2 cents worth,
> I'm not an engine specialist.
>
> basilisk
>
>

Try modifying an existing engine...and don't go hard over on it being a
2-stroke. I've often thought of trying to construct a full 9 or 7
cylinder aircraft radial using Harley engine parts - hell, those engines
have more in common with an air cooled radial than about anything I can
think of other than a Pratt & Whitney.

For your ultralight purpose, a basic V-twin would probably do, and I'd
suggest the fuel injected HD 88B counterbalanced one...just to keep
things smoother. The straight Dyna or touring Twin Cam 88 is lighter,
but I'm not sure how much vibration it would produce if hard mounted.

Something else you could do is use Harley studs and design your own
crank and case to make a flat twin, if you just want to build an engine
yourself - that would be a neat project, too.

If you need to use a reducer, you can machine your own pulley plate and
use a wide primary belt. Given that you'll be mounting the engine
behind a prop, you may also ba able to get away with shaving the fins to
lighten it a bit.

I'd also suggest you hot-rod the motor to a high compression setup -
that and the fuel injection will solve some horsepower vs altitude curve
problems for you - or at least help minimize them.

--
- Rufus

[frank]

On Mar 10, 9:02*pm, Rufus > wrote:
> durabol wrote:
> > The two main methods for homebuilt construction would be casting vs.
> > machining or some combination of both (probably the best option).
> > Forging probably isn't appropriate for home construction (either the
> > piston or connecting rod).
>
> > One method I have thought of is to produce a wax model of the engine
> > with molds (to a fairly high tolerance to minimize machining) which is
> > then cast using lost wax casting techniques. I planned to have an
> > integral cylinder head/cylinder/half the crank case (this is for an
> > opposed style engine). The only bolts would be to bolt the two halves
> > together.
>
> As someone whom has done lost wax casting, I wouldn't recommend doing
> that for something I was going to bet my life on...not without investing
> LARGE amounts of capital in equipment - a centrifugal or pressure
> injection foundry...sand casting (which I've also done) is a far better
> alternative for casting a raw engine casing. *Make a durable wooden
> master model, preferably of a hardwood.
>
> In any event, you're still going to have to sleeve the cylinders with
> some alloy of machined, durable steel - which will have to be hardened
> and polished in some way and interference fit into the block or stud.
> And you need to match coefficients of thermal expansion when choosing
> your materials in order to keep it all tight - same goes for choosing
> and tolerancing your bolts and every other component in direct
> contact...which means you also need to do some thermal analysis and
> figure out how hot, as well as how, your engine is going to run...
>
> > A completely machined engine would need a large block of aluminium to
> > start with which I'm not sure how practical that would be. Perhaps
> > lost foam casting could be used as a general model of the engine was
> > made in foam and then cast and the resulting casting could be
> > machined.
>
> > Brock
>
> Again - big investment in big machines to insure uniformity of the
> casting...which will kill the project (and the pilot) if you screw it
> up. *Hot spots, porosity, voids...not that simple. *Best way to
> spot/find/quality check castings involve die penetrant or x-ray.
>
> Also - don't overlook the fact that you are going to have to heat treat,
> case harden, or otherwise machine or post-work any part you produce
> depending on choice and application of materials...I don't know what
> kind of tools and resources the OP has at hand, but if he's starting
> from scratch he better be prepared to spend the amount of money he'd
> spend on a mid-size car in tooling just to get started with such a
> project...make it a large luxury car, now that I think about it...
>
> The far easier (and safer) alternative is to modify an existing engine -
> like a motorcycle engine - strip it down and just build the parts and
> accessories required to make it turn a prop. *And along the way one can
> also machine it's component parts down to lighten it...run it on the
> ground, if it breaks, you know you went too far.
>
> --
> * * * - Rufus (pilot, engineer, jeweler, model builder...yadda, yadda...)

Anything that flies a person has to be certified by the FAA anyway.
Especially homebuilts due to some fatal crashes early on.

[cavelamb[_2_]]

frank wrote:
>
> Anything that flies a person has to be certified by the FAA anyway.
> Especially homebuilts due to some fatal crashes early on.


When did this start???

[Jim Stewart]

cavelamb wrote:
> frank wrote:
>>
>> Anything that flies a person has to be certified by the FAA anyway.
>> Especially homebuilts due to some fatal crashes early on.
>
>
> When did this start???

It didn't. Experimental class is still around
and my friend still flies a VW engined plane.

[Charles Vincent]

cavelamb wrote:
> frank wrote:
>>
>> Anything that flies a person has to be certified by the FAA anyway.
>> Especially homebuilts due to some fatal crashes early on.
>
>
> When did this start???

Which? Stupidity on the internet or stupidity in our government?

Charles

[[email protected]]

On Mar 11, 8:17*am, Charles Vincent > wrote:

> > When did this start???
>
> Which? *Stupidity on the internet or stupidity in our government?


Government stupidity came first. Al G. just wanted to bring it to the
general public .................
===============
Leon

[Tim Wescott]

frank wrote:
> On Mar 10, 9:02 pm, Rufus > wrote:
>> durabol wrote:
>>> The two main methods for homebuilt construction would be casting vs.
>>> machining or some combination of both (probably the best option).
>>> Forging probably isn't appropriate for home construction (either the

-- snip --

>> like a motorcycle engine - strip it down and just build the parts and
>> accessories required to make it turn a prop. And along the way one can
>> also machine it's component parts down to lighten it...run it on the
>> ground, if it breaks, you know you went too far.
>>
>> --
>> - Rufus (pilot, engineer, jeweler, model builder...yadda, yadda...)
>
> Anything that flies a person has to be certified by the FAA anyway.
> Especially homebuilts due to some fatal crashes early on.

The FAA licensing process for homebuilts is much lighter weight than for
'regular' aircraft. People can and do convert automotive engines for
homebuilts, and fly them. There are many building processes that aren't
certified for general aviation, but which are acceptable to the FAA
inspectors for homebuilts.

Check the EAA website (eaa.org?) -- they'll have something.

--
Tim Wescott
Control system and signal processing consulting
www.wescottdesign.com

[cavelamb[_2_]]

wrote:
> On Mar 11, 8:17 am, Charles Vincent > wrote:
>
>>> When did this start???
>> Which? Stupidity on the internet or stupidity in our government?
>
>
> Government stupidity came first. Al G. just wanted to bring it to the
> general public .................
> ===============
> Leon

What? This?

Anything that flies a person has to be certified by the FAA anyway.
Especially homebuilts due to some fatal crashes early on.

This is completely false!

--

Richard Lamb
http://www.home.earthlink.net/~cavelamb/

[jan olieslagers[_2_]]

cavelamb schreef:
> What? This?
>
> Anything that flies a person has to be certified by the FAA anyway.
> Especially homebuilts due to some fatal crashes early on.
>
> This is completely false!

The sheer fact that he implies the FAA has worldwide authority shows he
doesn't know what he is talking about. Least said soonest forgotten.

[Jim Stewart]

cavelamb wrote:
> wrote:
>> On Mar 11, 8:17 am, Charles Vincent > wrote:
>>
>>>> When did this start???
>>> Which? Stupidity on the internet or stupidity in our government?
>>
>>
>> Government stupidity came first. Al G. just wanted to bring it to the
>> general public .................
>> ===============
>> Leon
>
> What? This?
>
> Anything that flies a person has to be certified by the FAA anyway.
> Especially homebuilts due to some fatal crashes early on.
>
> This is completely false!

Wrong.

My airplane, a Flight Design CTSW, has a
special light sport airworthiness certificate
and an uncertified Rotax 912ULS engine.

Rotax 912ULS engines are also the engine
of choice for many homebuilders.

[[email protected]]

On Thu, 11 Mar 2010 00:45:04 -0800 (PST), frank
> wrote:

>On Mar 10, 9:02Â*pm, Rufus > wrote:
>> durabol wrote:
>> > The two main methods for homebuilt construction would be casting vs.
>> > machining or some combination of both (probably the best option).
>> > Forging probably isn't appropriate for home construction (either the
>> > piston or connecting rod).
>>
>> > One method I have thought of is to produce a wax model of the engine
>> > with molds (to a fairly high tolerance to minimize machining) which is
>> > then cast using lost wax casting techniques. I planned to have an
>> > integral cylinder head/cylinder/half the crank case (this is for an
>> > opposed style engine). The only bolts would be to bolt the two halves
>> > together.
>>
>> As someone whom has done lost wax casting, I wouldn't recommend doing
>> that for something I was going to bet my life on...not without investing
>> LARGE amounts of capital in equipment - a centrifugal or pressure
>> injection foundry...sand casting (which I've also done) is a far better
>> alternative for casting a raw engine casing. Â*Make a durable wooden
>> master model, preferably of a hardwood.
>>
>> In any event, you're still going to have to sleeve the cylinders with
>> some alloy of machined, durable steel - which will have to be hardened
>> and polished in some way and interference fit into the block or stud.
>> And you need to match coefficients of thermal expansion when choosing
>> your materials in order to keep it all tight - same goes for choosing
>> and tolerancing your bolts and every other component in direct
>> contact...which means you also need to do some thermal analysis and
>> figure out how hot, as well as how, your engine is going to run...
>>
>> > A completely machined engine would need a large block of aluminium to
>> > start with which I'm not sure how practical that would be. Perhaps
>> > lost foam casting could be used as a general model of the engine was
>> > made in foam and then cast and the resulting casting could be
>> > machined.
>>
>> > Brock
>>
>> Again - big investment in big machines to insure uniformity of the
>> casting...which will kill the project (and the pilot) if you screw it
>> up. Â*Hot spots, porosity, voids...not that simple. Â*Best way to
>> spot/find/quality check castings involve die penetrant or x-ray.
>>
>> Also - don't overlook the fact that you are going to have to heat treat,
>> case harden, or otherwise machine or post-work any part you produce
>> depending on choice and application of materials...I don't know what
>> kind of tools and resources the OP has at hand, but if he's starting
>> from scratch he better be prepared to spend the amount of money he'd
>> spend on a mid-size car in tooling just to get started with such a
>> project...make it a large luxury car, now that I think about it...
>>
>> The far easier (and safer) alternative is to modify an existing engine -
>> like a motorcycle engine - strip it down and just build the parts and
>> accessories required to make it turn a prop. Â*And along the way one can
>> also machine it's component parts down to lighten it...run it on the
>> ground, if it breaks, you know you went too far.
>>
>> --
>> Â* Â* Â* - Rufus (pilot, engineer, jeweler, model builder...yadda, yadda...)
>
>Anything that flies a person has to be certified by the FAA anyway.
>Especially homebuilts due to some fatal crashes early on.

Not true.
Experimental/homebuilt can use ANY engine - absolutely no
certification required.

[Garry O]

"Tim Wescott" > wrote in message
...
> frank wrote:
>> On Mar 10, 9:02 pm, Rufus > wrote:
>>> durabol wrote:
>>>> The two main methods for homebuilt construction would be casting vs.
>>>> machining or some combination of both (probably the best option).
>>>> Forging probably isn't appropriate for home construction (either the
>
> -- snip --
>
>>> like a motorcycle engine - strip it down and just build the parts and
>>> accessories required to make it turn a prop. And along the way one can
>>> also machine it's component parts down to lighten it...run it on the
>>> ground, if it breaks, you know you went too far.
>>>
>>> --
>>> - Rufus (pilot, engineer, jeweler, model builder...yadda,
>>> yadda...)
>>
>> Anything that flies a person has to be certified by the FAA anyway.
>> Especially homebuilts due to some fatal crashes early on.
>
> The FAA licensing process for homebuilts is much lighter weight than for
> 'regular' aircraft. People can and do convert automotive engines for
> homebuilts, and fly them. There are many building processes that aren't
> certified for general aviation, but which are acceptable to the FAA
> inspectors for homebuilts.
>
> Check the EAA website (eaa.org?) -- they'll have something.
>

www.faa.gov the eaa is a pilot organisation, not a controling authotiry :-)

> --
> Tim Wescott
> Control system and signal processing consulting
> www.wescottdesign.com

--
Remember Altitude is more important than Attitude

[Garry O]

"Garry O" > wrote in message
u...
> "Tim Wescott" > wrote in message
> ...
>> frank wrote:
>>> On Mar 10, 9:02 pm, Rufus > wrote:
>>>> durabol wrote:
>>>>> The two main methods for homebuilt construction would be casting vs.
>>>>> machining or some combination of both (probably the best option).
>>>>> Forging probably isn't appropriate for home construction (either the
>>
>> -- snip --
>>
>>>> like a motorcycle engine - strip it down and just build the parts and
>>>> accessories required to make it turn a prop. And along the way one can
>>>> also machine it's component parts down to lighten it...run it on the
>>>> ground, if it breaks, you know you went too far.
>>>>
>>>> --
>>>> - Rufus (pilot, engineer, jeweler, model builder...yadda,
>>>> yadda...)
>>>
>>> Anything that flies a person has to be certified by the FAA anyway.
>>> Especially homebuilts due to some fatal crashes early on.
>>
>> The FAA licensing process for homebuilts is much lighter weight than for
>> 'regular' aircraft. People can and do convert automotive engines for
>> homebuilts, and fly them. There are many building processes that aren't
>> certified for general aviation, but which are acceptable to the FAA
>> inspectors for homebuilts.
>>
>> Check the EAA website (eaa.org?) -- they'll have something.
>>
>
> www.faa.gov the eaa is a pilot organisation, not a controling authotiry
> :-)
>
>> --
>> Tim Wescott
>> Control system and signal processing consulting
>> www.wescottdesign.com
>

and I must remember to read what is written after the first coffee of the
day 'DOH
your correct, the EAA will have a lot of information on homebuilt and
experimental A/C, they will also want you to get regular inspections during
the construction, even on experimental I think, and at various benchmarks
during the build.
personally I wouldn't fly with any home made engine, and by home made I'm
talking about things like casting your own cylinders etc, why re-invent the
wheel when there is a plethora of R&D'd engines that can more easily and
cheaply be converted.

--
Remember Altitude is more important than Attitude

[Jim Stewart]

Garry O wrote:
> "Garry O" > wrote in message
> u...
>> "Tim Wescott" > wrote in message
>> ...
>>> frank wrote:
>>>> On Mar 10, 9:02 pm, Rufus > wrote:
>>>>> durabol wrote:
>>>>>> The two main methods for homebuilt construction would be casting vs.
>>>>>> machining or some combination of both (probably the best option).
>>>>>> Forging probably isn't appropriate for home construction (either the
>>>
>>> -- snip --
>>>
>>>>> like a motorcycle engine - strip it down and just build the parts and
>>>>> accessories required to make it turn a prop. And along the way one
>>>>> can
>>>>> also machine it's component parts down to lighten it...run it on the
>>>>> ground, if it breaks, you know you went too far.
>>>>>
>>>>> --
>>>>> - Rufus (pilot, engineer, jeweler, model builder...yadda,
>>>>> yadda...)
>>>>
>>>> Anything that flies a person has to be certified by the FAA anyway.
>>>> Especially homebuilts due to some fatal crashes early on.
>>>
>>> The FAA licensing process for homebuilts is much lighter weight than
>>> for 'regular' aircraft. People can and do convert automotive engines
>>> for homebuilts, and fly them. There are many building processes that
>>> aren't certified for general aviation, but which are acceptable to
>>> the FAA inspectors for homebuilts.
>>>
>>> Check the EAA website (eaa.org?) -- they'll have something.
>>>
>>
>> www.faa.gov the eaa is a pilot organisation, not a controling
>> authotiry :-)
>>
>>> --
>>> Tim Wescott
>>> Control system and signal processing consulting
>>> www.wescottdesign.com
>>
>
> and I must remember to read what is written after the first coffee of
> the day 'DOH
> your correct, the EAA will have a lot of information on homebuilt and
> experimental A/C, they will also want you to get regular inspections
> during the construction, even on experimental I think, and at various
> benchmarks during the build.
> personally I wouldn't fly with any home made engine, and by home made
> I'm talking about things like casting your own cylinders etc, why
> re-invent the wheel when there is a plethora of R&D'd engines that can
> more easily and cheaply be converted.

I'd also point out that much of the homebuilt FAA
regulatory footwork is done by designated examiners
and inspectors that are EAA members.

[Tim Wescott]

Garry O wrote:
> "Garry O" > wrote in message
> u...
>> "Tim Wescott" > wrote in message
>> ...
>>> frank wrote:
>>>> On Mar 10, 9:02 pm, Rufus > wrote:
>>>>> durabol wrote:
>>>>>> The two main methods for homebuilt construction would be casting vs.
>>>>>> machining or some combination of both (probably the best option).
>>>>>> Forging probably isn't appropriate for home construction (either the
>>>
>>> -- snip --
>>>
>>>>> like a motorcycle engine - strip it down and just build the parts and
>>>>> accessories required to make it turn a prop. And along the way one
>>>>> can
>>>>> also machine it's component parts down to lighten it...run it on the
>>>>> ground, if it breaks, you know you went too far.
>>>>>
>>>>> --
>>>>> - Rufus (pilot, engineer, jeweler, model builder...yadda,
>>>>> yadda...)
>>>>
>>>> Anything that flies a person has to be certified by the FAA anyway.
>>>> Especially homebuilts due to some fatal crashes early on.
>>>
>>> The FAA licensing process for homebuilts is much lighter weight than
>>> for 'regular' aircraft. People can and do convert automotive engines
>>> for homebuilts, and fly them. There are many building processes that
>>> aren't certified for general aviation, but which are acceptable to
>>> the FAA inspectors for homebuilts.
>>>
>>> Check the EAA website (eaa.org?) -- they'll have something.
>>>
>>
>> www.faa.gov the eaa is a pilot organisation, not a controling
>> authotiry :-)
>>
>>> --
>>> Tim Wescott
>>> Control system and signal processing consulting
>>> www.wescottdesign.com
>>
>
> and I must remember to read what is written after the first coffee of
> the day 'DOH
> your correct, the EAA will have a lot of information on homebuilt and
> experimental A/C, they will also want you to get regular inspections
> during the construction, even on experimental I think, and at various
> benchmarks during the build.
> personally I wouldn't fly with any home made engine, and by home made
> I'm talking about things like casting your own cylinders etc, why
> re-invent the wheel when there is a plethora of R&D'd engines that can
> more easily and cheaply be converted.
>
My feeling was that while the FAA will give you enough rules to make a
swamp, the EAA will give you a map of the swamp so you can get through it!

--
Tim Wescott
Control system and signal processing consulting
www.wescottdesign.com

[Rufus]

frank wrote:
> On Mar 10, 9:02 pm, Rufus > wrote:
>> durabol wrote:
>>> The two main methods for homebuilt construction would be casting vs.
>>> machining or some combination of both (probably the best option).
>>> Forging probably isn't appropriate for home construction (either the
>>> piston or connecting rod).
>>> One method I have thought of is to produce a wax model of the engine
>>> with molds (to a fairly high tolerance to minimize machining) which is
>>> then cast using lost wax casting techniques. I planned to have an
>>> integral cylinder head/cylinder/half the crank case (this is for an
>>> opposed style engine). The only bolts would be to bolt the two halves
>>> together.
>> As someone whom has done lost wax casting, I wouldn't recommend doing
>> that for something I was going to bet my life on...not without investing
>> LARGE amounts of capital in equipment - a centrifugal or pressure
>> injection foundry...sand casting (which I've also done) is a far better
>> alternative for casting a raw engine casing. Make a durable wooden
>> master model, preferably of a hardwood.
>>
>> In any event, you're still going to have to sleeve the cylinders with
>> some alloy of machined, durable steel - which will have to be hardened
>> and polished in some way and interference fit into the block or stud.
>> And you need to match coefficients of thermal expansion when choosing
>> your materials in order to keep it all tight - same goes for choosing
>> and tolerancing your bolts and every other component in direct
>> contact...which means you also need to do some thermal analysis and
>> figure out how hot, as well as how, your engine is going to run...
>>
>>> A completely machined engine would need a large block of aluminium to
>>> start with which I'm not sure how practical that would be. Perhaps
>>> lost foam casting could be used as a general model of the engine was
>>> made in foam and then cast and the resulting casting could be
>>> machined.
>>> Brock
>> Again - big investment in big machines to insure uniformity of the
>> casting...which will kill the project (and the pilot) if you screw it
>> up. Hot spots, porosity, voids...not that simple. Best way to
>> spot/find/quality check castings involve die penetrant or x-ray.
>>
>> Also - don't overlook the fact that you are going to have to heat treat,
>> case harden, or otherwise machine or post-work any part you produce
>> depending on choice and application of materials...I don't know what
>> kind of tools and resources the OP has at hand, but if he's starting
>> from scratch he better be prepared to spend the amount of money he'd
>> spend on a mid-size car in tooling just to get started with such a
>> project...make it a large luxury car, now that I think about it...
>>
>> The far easier (and safer) alternative is to modify an existing engine -
>> like a motorcycle engine - strip it down and just build the parts and
>> accessories required to make it turn a prop. And along the way one can
>> also machine it's component parts down to lighten it...run it on the
>> ground, if it breaks, you know you went too far.
>>
>> --
>> - Rufus (pilot, engineer, jeweler, model builder...yadda, yadda...)
>
> Anything that flies a person has to be certified by the FAA anyway.
> Especially homebuilts due to some fatal crashes early on.

Depends on the Category, I think. But yeah...that's yet another mess I
wouldn't really want to have to tackle either!

--
- Rufus

[Rufus]

Jim Stewart wrote:
> cavelamb wrote:
>> frank wrote:
>>>
>>> Anything that flies a person has to be certified by the FAA anyway.
>>> Especially homebuilts due to some fatal crashes early on.
>>
>>
>> When did this start???
>
> It didn't. Experimental class is still around
> and my friend still flies a VW engined plane.

That's a heavier aircraft than an ultralight...not sure what they do
with ultralights, or light sport...anybody know about certs for those
two Categories/Classes?

--
- Rufus

[Rufus]

jan olieslagers wrote:
> cavelamb schreef:
>> What? This?
>>
>> Anything that flies a person has to be certified by the FAA anyway.
>> Especially homebuilts due to some fatal crashes early on.
>>
>> This is completely false!
>
> The sheer fact that he implies the FAA has worldwide authority shows he
> doesn't know what he is talking about. Least said soonest forgotten.

....maybe he meant FAI?..still..

--
- Rufus

[[email protected]]

On Thu, 11 Mar 2010 17:55:30 -0800, Rufus > wrote:

>Jim Stewart wrote:
>> cavelamb wrote:
>>> frank wrote:
>>>>
>>>> Anything that flies a person has to be certified by the FAA anyway.
>>>> Especially homebuilts due to some fatal crashes early on.
>>>
>>>
>>> When did this start???
>>
>> It didn't. Experimental class is still around
>> and my friend still flies a VW engined plane.
>
>That's a heavier aircraft than an ultralight...not sure what they do
>with ultralights, or light sport...anybody know about certs for those
>two Categories/Classes?
Ultralight in the USA is totally unregulated other than needing to be
rediculously light. The new sport aviation class I am not sure of -
but I do know certified engines are not required for all. Here in
Canada a class called "advanced ultralight" has some regulation - but
still no certified engine requirement.
Our "Amateur built" class has no engine certification requirements or
limits.

[Garry O]

"Tim Wescott" > wrote in message
...
> Garry O wrote:
>> "Garry O" > wrote in message
>> u...
>>> "Tim Wescott" > wrote in message
>>> ...
>>>> frank wrote:
>>>>> On Mar 10, 9:02 pm, Rufus > wrote:
>>>>>> durabol wrote:
>>>>>>> The two main methods for homebuilt construction would be casting vs.
>>>>>>> machining or some combination of both (probably the best option).
>>>>>>> Forging probably isn't appropriate for home construction (either the
>>>>
>>>> -- snip --
>>>>
>>>>>> like a motorcycle engine - strip it down and just build the parts and
>>>>>> accessories required to make it turn a prop. And along the way one
>>>>>> can
>>>>>> also machine it's component parts down to lighten it...run it on the
>>>>>> ground, if it breaks, you know you went too far.
>>>>>>
>>>>>> --
>>>>>> - Rufus (pilot, engineer, jeweler, model builder...yadda,
>>>>>> yadda...)
>>>>>
>>>>> Anything that flies a person has to be certified by the FAA anyway.
>>>>> Especially homebuilts due to some fatal crashes early on.
>>>>
>>>> The FAA licensing process for homebuilts is much lighter weight than
>>>> for 'regular' aircraft. People can and do convert automotive engines
>>>> for homebuilts, and fly them. There are many building processes that
>>>> aren't certified for general aviation, but which are acceptable to the
>>>> FAA inspectors for homebuilts.
>>>>
>>>> Check the EAA website (eaa.org?) -- they'll have something.
>>>>
>>>
>>> www.faa.gov the eaa is a pilot organisation, not a controling authotiry
>>> :-)
>>>
>>>> --
>>>> Tim Wescott
>>>> Control system and signal processing consulting
>>>> www.wescottdesign.com
>>>
>>
>> and I must remember to read what is written after the first coffee of the
>> day 'DOH
>> your correct, the EAA will have a lot of information on homebuilt and
>> experimental A/C, they will also want you to get regular inspections
>> during the construction, even on experimental I think, and at various
>> benchmarks during the build.
>> personally I wouldn't fly with any home made engine, and by home made I'm
>> talking about things like casting your own cylinders etc, why re-invent
>> the wheel when there is a plethora of R&D'd engines that can more easily
>> and cheaply be converted.
>>
> My feeling was that while the FAA will give you enough rules to make a
> swamp, the EAA will give you a map of the swamp so you can get through it!
>
> --
> Tim Wescott
> Control system and signal processing consulting
> www.wescottdesign.com

If the FAA is anything like CASA down here your 100% correct :-)

--
Remember Altitude is more important than Attitude

[Oliver Arend]

> not sure what they do with ultralights, or light sport...

LSA in the US (and any country that adopted these rules, I presume)
require their engines to comply with the industry standard ASTM F 2339
"Standard Practice for Design and Manufacture of Reciprocating Spark
Ignition Engines for Light Sport Aircraft". This it not an FAA
certification.

Oliver

[Frnak McKenney]

On Thu, 11 Mar 2010 07:20:47 -0600, cavelamb > wrote:
> frank wrote:
>>
>> Anything that flies a person has to be certified by the FAA anyway.
>> Especially homebuilts due to some fatal crashes early on.
>
>
> When did this start???

First recorded case I recall was some young punk named Icarus...





<grin>

--
It is the business of education to implant insight and respon-
sibility. It must turn irresponsible opinion into responsible
judgement and lead from chance and arbitrariness to the rational
lucidity of an intellectual order. -- Mies Van der Rohe
--
Frank McKenney, McKenney Associates
Richmond, Virginia / (804) 320-4887
Munged E-mail: frank uscore mckenney ayut mined spring dawt cahm (y'all)

[cavelamb[_2_]]

Frnak McKenney wrote:
> On Thu, 11 Mar 2010 07:20:47 -0600, cavelamb > wrote:
>> frank wrote:
>>> Anything that flies a person has to be certified by the FAA anyway.
>>> Especially homebuilts due to some fatal crashes early on.
>>
>> When did this start???
>
> First recorded case I recall was some young punk named Icarus...
>
>
>
>
>
> <grin>
>


No, this is mis-information.

The statement that anything that flies has to be certified by FAA is
categorically incorrect - as several have pointed out here.

Homebuilts are not certified at all.
Not approved, either.

a certificate of airworthiness is is not the same thing as a certified
design. Actually, the correct term is certificated, not certified.

The statements that started all this (top) i believe are from the model
community(?). They are certainly not from someone why knows anything
about experimental amateur built aircraft.


--

Richard Lamb
http://www.home.earthlink.net/~cavelamb/

[Jim Stewart]

Oliver Arend wrote:
>> not sure what they do with ultralights, or light sport...
>
> LSA in the US (and any country that adopted these rules, I presume)
> require their engines to comply with the industry standard ASTM F 2339
> "Standard Practice for Design and Manufacture of Reciprocating Spark
> Ignition Engines for Light Sport Aircraft". This it not an FAA
> certification.

Here's the actual cite from F2245-09:

7.2 Engines—Installed engines shall conform to Practice
F 2339 or Practice F 2538 or shall be type certificated or
otherwise approved under FAR-33, JAR-E, or JAR-22 Subpart
H standards.

And you are correct, it is not an FAA
certification.

[[email protected]]

While it would be too heavy and make too much power for a US UL,
how about converting a VW engine to a two stroke?

You might get something resembling one of the old McCullough
drone engines.

--

FF

[durabol[_2_]]

Thanks for the responses.

-I planned to have one carburetor (and crankcase) for both cylinders.

-I have access to a lathe and a milling machine but I don't have that
much experience with them so I'll have to learn as I go or get someone
else to do the machining

-I do plan to build the engine in a modular way so I suppose I could
add more cylinders.

-I do have some experience with lost wax casting although not with
much success. The engine casting that I had envisioned may be too
complicated for the simple gravity casting techniques I was planning.
I also worry about hot tears of the cylinder as the aluminium cools
and casting decent heat fins.

-For the cylinder I was planning on just an aluminium wall since I
have heard "cheap" lawn mower engine can get 500h on them. I though
that the bearings in the engine will probably need to be replaced in a
few hundred hours anyways, so the bore could be resized then.

Brock

[Tim Wescott]

durabol wrote:
> Thanks for the responses.
>
> -I planned to have one carburetor (and crankcase) for both cylinders.
>
> -I have access to a lathe and a milling machine but I don't have that
> much experience with them so I'll have to learn as I go or get someone
> else to do the machining
>
> -I do plan to build the engine in a modular way so I suppose I could
> add more cylinders.
>
> -I do have some experience with lost wax casting although not with
> much success. The engine casting that I had envisioned may be too
> complicated for the simple gravity casting techniques I was planning.
> I also worry about hot tears of the cylinder as the aluminium cools
> and casting decent heat fins.
>
> -For the cylinder I was planning on just an aluminium wall since I
> have heard "cheap" lawn mower engine can get 500h on them. I though
> that the bearings in the engine will probably need to be replaced in a
> few hundred hours anyways, so the bore could be resized then.

With some pretty fancy metallurgy you can use an aluminum cylinder wall.
It's how the Chevy Vega was done, and it worked great -- except when
it didn't.

There are other treatments that'll let you run a 'plain' aluminum
cylinder -- but none of them are simple, that I know of.

--
Tim Wescott
Control system and signal processing consulting
www.wescottdesign.com

[Ed Huntress]

"Tim Wescott" > wrote in message
...
> durabol wrote:
>> Thanks for the responses.
>>
>> -I planned to have one carburetor (and crankcase) for both cylinders.
>>
>> -I have access to a lathe and a milling machine but I don't have that
>> much experience with them so I'll have to learn as I go or get someone
>> else to do the machining
>>
>> -I do plan to build the engine in a modular way so I suppose I could
>> add more cylinders.
>>
>> -I do have some experience with lost wax casting although not with
>> much success. The engine casting that I had envisioned may be too
>> complicated for the simple gravity casting techniques I was planning.
>> I also worry about hot tears of the cylinder as the aluminium cools
>> and casting decent heat fins.
>>
>> -For the cylinder I was planning on just an aluminium wall since I
>> have heard "cheap" lawn mower engine can get 500h on them. I though
>> that the bearings in the engine will probably need to be replaced in a
>> few hundred hours anyways, so the bore could be resized then.
>
> With some pretty fancy metallurgy you can use an aluminum cylinder wall.
> It's how the Chevy Vega was done, and it worked great -- except when it
> didn't.

And the Porsche 928 V8, which worked quite well.

>
> There are other treatments that'll let you run a 'plain' aluminum
> cylinder -- but none of them are simple, that I know of.

The more interesting ones were Kawasaki's explosive coating of, first, an
iron wire, and then a molybdenum wire, which they used in a few racing
engines. They'd run a wire down the middle of the cylinder and run a pulse
of electrical current through it at some God-awful amperage, which would
vaporize the wire and coat the cylinder walls with iron and then moly.

Porsche and a few others used porous chrome platings; Porsche, in one of the
early versions of their Carrera engine, which I think was the 1350 cc model
used in early Speedsters and maybe the 550 Spyder.

The plain aluminum cylinders used in the Vega and the Porsche 928 used a
hypereutectoid silicon-aluminum alloy that precipitated crystals of silicon
when they cooled after casting. Mercury outboards used that method, too,
IIRC. Some Power Products 2-stroke lawnmowers used a similar alloy, but with
less silicon. Those alloys are similar to the ones used to cast pistons
today.

--
Ed Huntress


>
> --
> Tim Wescott
> Control system and signal processing consulting
> www.wescottdesign.com

[Jim Stewart]

Ed Huntress wrote:

> The plain aluminum cylinders used in the Vega and the Porsche 928 used a
> hypereutectoid silicon-aluminum alloy that precipitated crystals of silicon
> when they cooled after casting. Mercury outboards used that method, too,
> IIRC. Some Power Products 2-stroke lawnmowers used a similar alloy, but with
> less silicon. Those alloys are similar to the ones used to cast pistons
> today.

Don't most newer Briggs engines use AL
or pot metal block/cylinders?

[Ed Huntress]

"Jim Stewart" > wrote in message
...
> Ed Huntress wrote:
>
>> The plain aluminum cylinders used in the Vega and the Porsche 928 used a
>> hypereutectoid silicon-aluminum alloy that precipitated crystals of
>> silicon when they cooled after casting. Mercury outboards used that
>> method, too, IIRC. Some Power Products 2-stroke lawnmowers used a similar
>> alloy, but with less silicon. Those alloys are similar to the ones used
>> to cast pistons today.
>
> Don't most newer Briggs engines use AL
> or pot metal block/cylinders?

'Don't know. I seriously doubt if it's pot metal.

--
Ed Huntress

[TonyW]

On 3/17/2010 10:34 AM, Jim Stewart wrote:
> Ed Huntress wrote:
>
>> The plain aluminum cylinders used in the Vega and the Porsche 928 used
>> a hypereutectoid silicon-aluminum alloy that precipitated crystals of
>> silicon when they cooled after casting. Mercury outboards used that
>> method, too, IIRC. Some Power Products 2-stroke lawnmowers used a
>> similar alloy, but with less silicon. Those alloys are similar to the
>> ones used to cast pistons today.
>
> Don't most newer Briggs engines use AL
> or pot metal block/cylinders?

AL but it doesn't last all that long. Tecumseh uses a thin cast in iron
sleeve and that's one of the big reasons their engines last longer. I
also bet the better B&S engines like the Vanguard V twins are sleeved...

Tony

[[email protected]]

In article >, Tim Wescott > wrote:
>durabol wrote:
>> Thanks for the responses.
>>
>> -I planned to have one carburetor (and crankcase) for both cylinders.
>>
>> -I have access to a lathe and a milling machine but I don't have that
>> much experience with them so I'll have to learn as I go or get someone
>> else to do the machining
>>
>> -I do plan to build the engine in a modular way so I suppose I could
>> add more cylinders.
>>
>> -I do have some experience with lost wax casting although not with
>> much success. The engine casting that I had envisioned may be too
>> complicated for the simple gravity casting techniques I was planning.
>> I also worry about hot tears of the cylinder as the aluminium cools
>> and casting decent heat fins.
>>
>> -For the cylinder I was planning on just an aluminium wall since I
>> have heard "cheap" lawn mower engine can get 500h on them. I though
>> that the bearings in the engine will probably need to be replaced in a
>> few hundred hours anyways, so the bore could be resized then.
>
>With some pretty fancy metallurgy you can use an aluminum cylinder wall.
> It's how the Chevy Vega was done, and it worked great -- except when
>it didn't.
>
>There are other treatments that'll let you run a 'plain' aluminum
>cylinder -- but none of them are simple, that I know of.
>
don't forget wet sleeving.

[willshak]

Jim Stewart wrote the following:
> Ed Huntress wrote:
>
>> The plain aluminum cylinders used in the Vega and the Porsche 928
>> used a hypereutectoid silicon-aluminum alloy that precipitated
>> crystals of silicon when they cooled after casting. Mercury outboards
>> used that method, too, IIRC. Some Power Products 2-stroke lawnmowers
>> used a similar alloy, but with less silicon. Those alloys are similar
>> to the ones used to cast pistons today.
>
> Don't most newer Briggs engines use AL
> or pot metal block/cylinders?
But they have cast iron cylinder sleeves.

--

Bill
In Hamptonburgh, NY
In the original Orange County. Est. 1683
To email, remove the double zeroes after @

[bigegg]

two words:

burt munroe

as an example of home-cast/home machined engines.

--
bigegg

[Garry O]

"bigegg" > wrote in message
...
> two words:
>
> burt munroe
>
> as an example of home-cast/home machined engines.
>
> --
> bigegg

but he started with a manufactured engine, he didn't build it from scratch.
He also had a LOT of failures before he got everything working, are you
willing to do that with an AC engine ??

--
Remember Altitude is more important than Attitude

[Grider Pirate]

On Mar 16, 4:48*pm, durabol > wrote:
> Thanks for the responses.
>
> -I planned to have one carburetor (and crankcase) for both cylinders.


Shared carb and crankcase locks you into simultaneous firing of the
two opposing cylinders

>
> -I have access to a lathe and a milling machine but I don't have that
> much experience with them so I'll have to learn as I go or get someone
> else to do the machining
>
> -I do plan to build the engine in a modular way so I suppose I could
> add more cylinders.
>
> -I do have some experience with lost wax casting although not with
> much success. The engine casting that I had envisioned may be too
> complicated for the simple gravity casting techniques I was planning.
> I also worry about hot tears of the cylinder as the aluminium cools
> and casting decent heat fins.
>
> -For the cylinder I was planning on just an aluminium wall since I
> have heard "cheap" lawn mower engine can get 500h on them. I though
> that the bearings in the engine will probably need to be replaced in a
> few hundred hours anyways, so the bore could be resized then.

Those are four stroke engines, with no large holes in the cylinder
walls trying to swallow the rings with every stroke. They are also
generously lubricated with splashed oil from the crankcase, which you
won't have in a two stroke. Remember that the only lubrication in a
two-stroke is what's mixed in the fuel, or the tiny quantities that
are injected directly into the lower end bearings, (if you have an oil
pump like some two-stroke street bikes) where it's then mixed with the
fuel/air charge.
>
> Brock

Please get a copy (or download) of Gordon Jennings "Two Stroke Tuner's
Handbook" before starting. It was my 'Bible' when I did two stroke
performance development for a living.

[Fred the Red Shirt]

On Mar 18, 2:47*pm, Grider Pirate > wrote:
> On Mar 16, 4:48*pm, durabol > wrote:
>
> > Thanks for the responses.
>
> > -I planned to have one carburetor (and crankcase) for both cylinders.
>
> Shared carb and crankcase locks you into simultaneous firing of the
> two opposing cylinders
>

Not necessarily. What you describe is commonly called a 'boxer'
configuration.

You can also alternate the cylinders. That can simplify a lot, for
instance
the cylinders can be joined to a common, rigid scottish yoke. That
will
also vibrate horribly and probably shake itself apart. But people
have
tried it, google for Bourke engine, which has a small cult-like
following
on line.

Maybe if you configured a Bourke with multiple banks of 2-cylinders
each, rotating each bank around the crank by 360/n degrees, where
n is the number of cylinders, that would smooth out the vibration
issue.
The result would be a sort of 2-stroke radial.

[Fred the Red Shirt]

On Mar 17, 2:32*am, Tim Wescott > wrote:
> ...
>
> With some pretty fancy metallurgy you can use an aluminum cylinder wall.
> * It's how the Chevy Vega was done, and it worked great -- except when
> it didn't.
> ...

Which I thought was all of the time. I never heard of a Vega engine
that
lasted past 50,000 miles, or Vega body that wasn't rust perforated
after it's
second winter in the rust belt.

Had it been built to last the Vega would have been a great little
car.

--

FF

[Tim Wescott]

Fred the Red Shirt wrote:
> On Mar 17, 2:32 am, Tim Wescott > wrote:
>> ...
>>
>> With some pretty fancy metallurgy you can use an aluminum cylinder wall.
>> It's how the Chevy Vega was done, and it worked great -- except when
>> it didn't.
>> ...
>
> Which I thought was all of the time. I never heard of a Vega engine
> that
> lasted past 50,000 miles, or Vega body that wasn't rust perforated
> after it's
> second winter in the rust belt.
>
> Had it been built to last the Vega would have been a great little
> car.

There's an interesting Wikipedia article on the origins of the Chevy
Vega. Apparently it was designed by GM corporate engineering, and
shoved down Chevy's throat. Chevy wasn't allowed to make _any_
engineering changes, they were very grudging about building the thing,
and that was a huge part of the problem.

Apparently the wear point on the Vega engine wasn't the cylinder walls
at all -- it was the valve guides*. But the oil leakage** got blamed on
the cylinder walls because who could believe in an aluminum cylinder
bore? For it's size it's certainly a damn strong engine.

* Which were as new and innovative as the rest of the engine, just
wrong. If you're going to make something that's new and innovative,
identify the parts that _need_ to be new and innovative, and do the
_rest_ of the thing with old reliable technology. Then when that works,
go back and innovatize the rest of the thing, one system element at a time.

** "Fill er up and check the gas while you're at it!"

--
Tim Wescott
Control system and signal processing consulting
www.wescottdesign.com

[TonyW]

On 3/30/2010 10:22 AM, Tim Wescott wrote:

> There's an interesting Wikipedia article on the origins of the Chevy
> Vega. Apparently it was designed by GM corporate engineering, and shoved
> down Chevy's throat. Chevy wasn't allowed to make _any_ engineering
> changes, they were very grudging about building the thing, and that was
> a huge part of the problem.
>
> Apparently the wear point on the Vega engine wasn't the cylinder walls
> at all -- it was the valve guides*. But the oil leakage** got blamed on
> the cylinder walls because who could believe in an aluminum cylinder
> bore? For it's size it's certainly a damn strong engine.
>
> * Which were as new and innovative as the rest of the engine, just
> wrong. If you're going to make something that's new and innovative,
> identify the parts that _need_ to be new and innovative, and do the
> _rest_ of the thing with old reliable technology. Then when that works,
> go back and innovatize the rest of the thing, one system element at a time.
>

That was only 2 of the trifecta of problems with that engine. The last
problem was the Vega engine cooked it's oil to a tar like sludge in a
short amount of time. I've also heard that and oil cooler didn't help
much because part of the problem was in that oil pooled in the cylinder
head too long and picked up too much heat there.

Tony

[[email protected]]

On Tue, 30 Mar 2010 10:22:34 -0700, Tim Wescott >
wrote:

>Fred the Red Shirt wrote:
>> On Mar 17, 2:32 am, Tim Wescott > wrote:
>>> ...
>>>
>>> With some pretty fancy metallurgy you can use an aluminum cylinder wall.
>>> It's how the Chevy Vega was done, and it worked great -- except when
>>> it didn't.
>>> ...
>>
>> Which I thought was all of the time. I never heard of a Vega engine
>> that
>> lasted past 50,000 miles, or Vega body that wasn't rust perforated
>> after it's
>> second winter in the rust belt.
>>
>> Had it been built to last the Vega would have been a great little
>> car.
>
>There's an interesting Wikipedia article on the origins of the Chevy
>Vega. Apparently it was designed by GM corporate engineering, and
>shoved down Chevy's throat. Chevy wasn't allowed to make _any_
>engineering changes, they were very grudging about building the thing,
>and that was a huge part of the problem.
>
>Apparently the wear point on the Vega engine wasn't the cylinder walls
>at all -- it was the valve guides*. But the oil leakage** got blamed on
>the cylinder walls because who could believe in an aluminum cylinder
>bore? For it's size it's certainly a damn strong engine.
>

Totally not true. The only fix for the extreme oil burning was to
sleeve the block - and that is not required for valve guide problems.
When they were running well they WERE very torquy engines, giving the
impression they were a lot bigger and "stronger" than they were.


>* Which were as new and innovative as the rest of the engine, just
>wrong. If you're going to make something that's new and innovative,
>identify the parts that _need_ to be new and innovative, and do the
>_rest_ of the thing with old reliable technology. Then when that works,
>go back and innovatize the rest of the thing, one system element at a time.
>
>** "Fill er up and check the gas while you're at it!"

[[email protected]]

On Mar 11, 3:20*am, Rufus > wrote:
> basilisk wrote:
> > "Lloyd E. Sponenburgh" <lloydspinsidemindspring.com> wrote in message
> . 3.70...
> >> "basilisk" > fired this volley in news:J4Nln.198564
> >> :
>
> >>> you will have to provide a slave cylinder or roots type blower
> >>> to move the air.
>
> >> Some variants use a cylinder skirt with reed valving.
>
> >> LLoyd
>
> > You're right, *I didn't really consider that before posting.
>
> > I supposed it could be worked out but that looks hard to
> > do in a completely bottom assembled engine, just my 2 cents worth,
> > I'm not an engine specialist.
>
> > basilisk
>
> Try modifying an existing engine...and don't go hard over on it being a
> 2-stroke. *I've often thought of trying to construct a full 9 or 7
> cylinder aircraft radial using Harley engine parts - hell, those engines
> have more in common with an air cooled radial than about anything I can
> think of other than a Pratt & Whitney.
>
<SNIP>
>
> --
> * * * - Rufus

Worth noting:

there is a radial project out there with quite a few builders that
uses VW jugs and a custom crankcase and heads. Around 100hp if I
remember correctly.

There are also a couple of half VW engine projects with plans
available.

If you take a stroll around the national air and space museum you will
get a feel for the art that went into many of the early engines. The
old designers and machinists were a different breed, and their work
inspires awe in any mechanically inclined mind. It is worth noting
that many of the older radial and fan engine configurations used a pie-
wedge style crankcase, where the cylinder and the case were a single
piece, and the crankcase bolted together in pieces arranged in
circumference to the crankshaft.

With modern alloys and machining techniques, I've wondered if
returning to this style might be tolerable for a small engine today.
Lawn mowers are done similarly, and so I'd imagine an engine designed
in this fashion would scale up quickly from a production standpoint.

While building a new engine solely for art is a lofty goal, I can't
really see it for any other reason. What performance specs could you
be looking for that aren't currently available in a production engine,
or are not otherwise achievable by making minor modifications to a
production engine?

The engine of interest to me lately is the new subaru TDI boxer
motor. Wow that thing is fancy, and I'm hoping it makes its way to
the states some time soon. With modern boosting techniques I'd also
like to see the packard aero diesel configuration revisited, perhaps
integrating some of the features in the elsbett engines. .

If I was heading off in the scratch built direction, I would outsource
the casting process. There are many shops domestic and overseas that
can do short runs of castings based on a provided dxf file. It is
unlikely that a backyard foundry will ever get close to the level of
detail these shops can create. I would probably search far and wide
before starting to CAD the thing up.

Of course, thinking down the road, if ever I should build my own bird,
I'm thinking Rotec, or PZL Franklin. I'd like to go heavy kung fu into
engine design, but it is just way to much work, for way to little
optimization.

Thanks!

[Rufus]

wrote:
> On Mar 11, 3:20 am, Rufus > wrote:
>> basilisk wrote:
>>> "Lloyd E. Sponenburgh" <lloydspinsidemindspring.com> wrote in message
>>> . 3.70...
>>>> "basilisk" > fired this volley in news:J4Nln.198564
>>>> :
>>>>> you will have to provide a slave cylinder or roots type blower
>>>>> to move the air.
>>>> Some variants use a cylinder skirt with reed valving.
>>>> LLoyd
>>> You're right, I didn't really consider that before posting.
>>> I supposed it could be worked out but that looks hard to
>>> do in a completely bottom assembled engine, just my 2 cents worth,
>>> I'm not an engine specialist.
>>> basilisk
>> Try modifying an existing engine...and don't go hard over on it being a
>> 2-stroke. I've often thought of trying to construct a full 9 or 7
>> cylinder aircraft radial using Harley engine parts - hell, those engines
>> have more in common with an air cooled radial than about anything I can
>> think of other than a Pratt & Whitney.
>>
> <SNIP>
>> --
>> - Rufus
>
> Worth noting:
>
> there is a radial project out there with quite a few builders that
> uses VW jugs and a custom crankcase and heads. Around 100hp if I
> remember correctly.
>
> There are also a couple of half VW engine projects with plans
> available.
>
> If you take a stroll around the national air and space museum you will
> get a feel for the art that went into many of the early engines. The
> old designers and machinists were a different breed, and their work
> inspires awe in any mechanically inclined mind. It is worth noting
> that many of the older radial and fan engine configurations used a pie-
> wedge style crankcase, where the cylinder and the case were a single
> piece, and the crankcase bolted together in pieces arranged in
> circumference to the crankshaft.
>
> With modern alloys and machining techniques, I've wondered if
> returning to this style might be tolerable for a small engine today.
> Lawn mowers are done similarly, and so I'd imagine an engine designed
> in this fashion would scale up quickly from a production standpoint.
>
> While building a new engine solely for art is a lofty goal, I can't
> really see it for any other reason. What performance specs could you
> be looking for that aren't currently available in a production engine,
> or are not otherwise achievable by making minor modifications to a
> production engine?
>
> The engine of interest to me lately is the new subaru TDI boxer
> motor. Wow that thing is fancy, and I'm hoping it makes its way to
> the states some time soon. With modern boosting techniques I'd also
> like to see the packard aero diesel configuration revisited, perhaps
> integrating some of the features in the elsbett engines. .
>
> If I was heading off in the scratch built direction, I would outsource
> the casting process. There are many shops domestic and overseas that
> can do short runs of castings based on a provided dxf file. It is
> unlikely that a backyard foundry will ever get close to the level of
> detail these shops can create. I would probably search far and wide
> before starting to CAD the thing up.
>
> Of course, thinking down the road, if ever I should build my own bird,
> I'm thinking Rotec, or PZL Franklin. I'd like to go heavy kung fu into
> engine design, but it is just way to much work, for way to little
> optimization.
>
> Thanks!
>

Well said. And not only might I outsource the castings, I'd also be
inclined to outsource heat or chemical treatments, or forgings.

Particularly since I'd be staking my life on the end product...I've
become a lot more safety minded since I became a jumper...

--
- Rufus