The Homebuilt Engine, Part 1

[[email protected]]

If you've read the latest 'Sport Aviation' you were no doubt impressed
by the 'New Engines for Experimental Aircraft' (page 35). The
infomercial shows a few engines with prices starting at about ten
grand, topping out at more than $50k, chump change for all those folks
dedicated to revitalizing grass-roots aviation in America.

For a whiff of reality, go over to GM's industrial engine page and
take a look at their V2400. In fact, don't just take a look at it,
figure out some way to get your hands on one.

Now turn it upside down and call me on the phone.

Once we have the thing running inverted we'll figure out how to
fabricate a carbon-fiber sump and valve cover. Carbon-fiber because
the alternative is cast aluminum and odds are, we don't have the
required depth of machining talent to produce a finished product from
a raw casting (although the guys did exactly that for the O-290-G back
in John Thorpe's day). With carbon-fiber we can fabricate the things
locally.

What do we get for our trouble? A 75hp water-cooled engine that
produces those 75 horses at an rpm suitable for twirling a prop.

What do we do with it? We put it in a Pietenpol. Or any other low-
tech, two-seater.

(Why invert it? Because that puts the thrust-line in the proper place
without filling your forward vision with cylinder heads and
radiators.)

Is it expensive? Probably. It's being manufactured in Brazil and the
way our Bail-Out Bucks are depreciating, we are well on our way to
becoming a Third World Nation. But it's an INDUSTRIAL engine, meaning
there's going to be a lot of them available.

Inverting an engine is fairly common in aviation; there's some tricks
to it but no mysteries.

Why the Pietenpol? Well... why NOT? It's a proven design and the
weight of the V2400 is close to that of the Model A. It's a two-
seater, which is almost a necessity if you want to stimulate grass-
roots aviation, and its fabrication calls for only a modest level of
skills. Indeed, if you participate in building a Primary Glider you
will have experienced virtually all of the skills needed to build a
Piet.

Food for thought.

-R.S.Hoover

[Copperhead]

Nice post Bob, Your correct these engines aren't cheap but when you
consider a Corvair aircraft engine built for you runs close to 8 grand
and a VW aircraft engine in the 70-80 HP range rund in the 5-6+ grand
range excluding props, hubs, mounts, etc then a new water cooled
engine like this does look pretty good afterall.

Joe

[Morgans[_2_]]

"Copperhead" > wrote

> and a VW aircraft engine in the 70-80 HP range rund in the 5-6+ grand

A 70 HP VW engine does not exist. Not if you want it to run more than 30
hours or so.
--
Jim in NC

[Copperhead]

On Sep 20, 4:45*pm, "Morgans" > wrote:
> "Copperhead" > wrote
>
> > and a VW aircraft engine in the 70-80 HP range rund in the 5-6+ grand
>
> A 70 HP VW engine does not exist. *Not if you want it to run more than 30
> hours or so.
> --
> Jim in NC

I know that Jim, but if you read all of the wonder add's you'll be
told that you can build or buy a 30, 60, 76, 80, 85, 90, 100+ peak HP
VW engine and do wonderful things with it. Of course no one explains
what to do with all of the heat generated by that much power either.
Me, I'll be happy with a reliable VW stoker aircraft engine build set
up the way Bob writes about. But hey, what do I know?

[cavelamb himself[_4_]]

Copperhead wrote:
> On Sep 20, 4:45 pm, "Morgans" > wrote:
>
>>"Copperhead" > wrote
>>
>>
>>>and a VW aircraft engine in the 70-80 HP range rund in the 5-6+ grand
>>
>>A 70 HP VW engine does not exist. Not if you want it to run more than 30
>>hours or so.
>>--
>>Jim in NC
>
>
> I know that Jim, but if you read all of the wonder add's you'll be
> told that you can build or buy a 30, 60, 76, 80, 85, 90, 100+ peak HP
> VW engine and do wonderful things with it. Of course no one explains
> what to do with all of the heat generated by that much power either.
> Me, I'll be happy with a reliable VW stoker aircraft engine build set
> up the way Bob writes about. But hey, what do I know?


Then you have a 40 horse engine...

--

Richard

(remove the X to email)

[[email protected]]

On Sep 20, 2:59*pm, Copperhead > wrote:
> On Sep 20, 4:45*pm, "Morgans" > wrote:
>
> > "Copperhead" > wrote
>
> > > and a VW aircraft engine in the 70-80 HP range rund in the 5-6+ grand
>
> > A 70 HP VW engine does not exist. *Not if you want it to run more than 30
> > hours or so.
-----------------------------------------------------------------------------

Harbor Freight is offering a Leak-Down Tester for $30 ( Item
#94190-3RBH, on page 7 in catalog 768-D)

If you operate your engine with a SUSTAINED output level equal to
70hp, the odds are it would fail to pass your leak-down test at 25
hours. What you chose to do with it at that point is up to you but a
surprising percentage of flying VW owners simply keep on flying the
thing... until they suffer a catastrophic valve failure, which can
cost them a new engine.

If your goal is to always operate your engine at high levels of output
the wiser course is to have FOUR heads, two installed on the engine
and a freshly overhauled pair on the shelf ready for use. But at high
levels of output don't be surprised if your TBO is 25 hours or less.

The T4 engine does a bit better, thanks to its greater fin area.

For maximum TBO you'll have to operate your engine BELOW its point of
Maximum Sustained Output, which for the Type 1 is between 35 and 45
hp, depending on the local atmosphere. At that level of output you
can expect to see about 200 hours before the exhaust valves fail the
leak-down test. At that point you should pull the heads and do the
wiggle test. If the heads pass the wiggle test (ie, the valve & guide
are still within spec), you may elect to simply lap the exhaust
valves. But when the head fails the wiggle test it's time to replace
the exhaust valves and their guides, a relatively simple task if
you're tooled up for it. (See any of several articles that address
this chore.) Here again, the wiser course (in my opinion) is to
maintain a spare SET of heads. This allows you to simply swap heads,
giving you up to 200 flying hours to overhaul the removed set.

What sets my ass on fire is the guys who say their engine puts out
80hp... and in the next breath tell all the newbies it only burns 3
gallons per hour... without bothering to explain that the first figure
has NOTHING TO DO with the second. (Three gallons per hour is about
36 horsepower.)

-Bob Hoover

[Copperhead]

On Sep 20, 5:45*pm, " > wrote:
> On Sep 20, 2:59*pm, Copperhead > wrote:> On Sep 20, 4:45*pm, "Morgans" > wrote:
>
> > > "Copperhead" > wrote
>
> > > > and a VW aircraft engine in the 70-80 HP range rund in the 5-6+ grand
>
> > > A 70 HP VW engine does not exist. *Not if you want it to run more than 30
> > > hours or so.
>
> ---------------------------------------------------------------------------*--
>
> Harbor Freight is offering a Leak-Down Tester for $30 ( Item
> #94190-3RBH, on page 7 in catalog 768-D)
>
> If you operate your engine with a SUSTAINED output level equal to
> 70hp, the odds are it would fail to pass your leak-down test at 25
> hours. *What you chose to do with it at that point is up to you but a
> surprising percentage of flying VW owners simply keep on flying the
> thing... until they suffer a catastrophic valve failure, which can
> cost them a new engine.
>
> If your goal is to always operate your engine at high levels of output
> the wiser course is to have FOUR heads, two installed on the engine
> and a freshly overhauled pair on the shelf ready for use. *But at high
> levels of output don't be surprised if your TBO is 25 hours or less.
>
> The T4 engine does a bit better, thanks to its greater fin area.
>
> For maximum TBO you'll have to operate your engine BELOW its point of
> Maximum Sustained Output, which for the Type 1 is between 35 and 45
> hp, depending on the local atmosphere. *At that level of output you
> can expect to see about 200 hours before the exhaust valves fail the
> leak-down test. *At that point you should pull the heads and do the
> wiggle test. *If the heads pass the wiggle test (ie, the valve & guide
> are still within spec), you may elect to simply lap the exhaust
> valves. *But when the head fails the wiggle test it's time to replace
> the exhaust valves and their guides, a relatively simple task if
> you're tooled up for it. *(See any of several articles that address
> this chore.) *Here again, the wiser course (in my opinion) is to
> maintain a spare SET of heads. *This allows you to simply swap heads,
> giving you up to 200 flying hours to overhaul the removed set.
>
> What sets my ass on fire is the guys who say their engine puts out
> 80hp... and in the next breath tell all the newbies it only burns 3
> gallons per hour... without bothering to explain that the first figure
> has NOTHING TO DO with the second. *(Three gallons per hour is about
> 36 horsepower.)
>
> -Bob Hoover

Your my hero Bob, you tell it like it is and don't pull any punches.
Everything I'd researched here and elsewhere written by you and a
select few others has been just what you've written here. I was
throwing in some tongue in cheek humor because I remembered reading
about a commerical VW engine builders product line a while back. He
never replied to my information request as to TBO and cruise HP. Oh
well I guess he didn't think I was a potential buyer. ;-)

[Flyingmonk[_1_]]

On Sep 20, 5:45*pm, "Morgans" > wrote:
> "Copperhead" > wrote
>
> > and a VW aircraft engine in the 70-80 HP range rund in the 5-6+ grand
>
> A 70 HP VW engine does not exist. *Not if you want it to run more than 30
> hours or so.
> --
> Jim in NC

Hey Teach! Hope all is well with you and your family. Haven't
checked in here in years. I have some questions I think you can
answer. Is your email here OK? If not, please email me one that
works.

Thanks,
Monk

[Morgans[_2_]]

"Flyingmonk" > wrote

Hey Teach! Hope all is well with you and your family. Haven't
checked in here in years. I have some questions I think you can
answer. Is your email here OK? If not, please email me one that
works.

Yep, it works if you toss out the big letter trash before you send it. <g>

Good to see you stop by. Things have changed, but yet they are the same.
;-)
--
Jim in NC

[Flyingmonk[_1_]]

On Sep 21, 10:51*am, "Morgans" > wrote:
> "Flyingmonk" > wrote
>
> Hey Teach! *Hope all is well with you and your family. *Haven't
> checked in here in years. *I have some questions I think you can
> answer. *Is your email here OK? *If not, please email me one that
> works.
>
> Yep, it works if you toss out the big letter trash before you send it. <g>
>
> Good to see you stop by. *Things have changed, but yet they are the same.
> ;-)
> --
> Jim in NC

I already got my answers from another friend Jim. Thanks just the
same though.

Monk