Airplane design.

[Stuart Grey]

I was looking at the design of the Murphy Moose:

http://www.murphyair.com/

They put the cost at about 100k$, cheap compared to the two Cessna's and
the Bush Hawk to which Murphy compares the Moose:

http://www.murphyair.com/Product_Info/Super/compare.htm

From their engine page, half of that cost is probably engine.

Empty weight is 1450 pounds.

At Boeing surplus, a sheet of aluminum runs about $1.64/pound (Not
including the Boeing discount). At 1450 pounds, that's only about $2400
worth of aluminum. The rest is labor (they half build the airplane),
mark up, insurance, support and so on. A really cheap guy who doesn't
have a lot of money, such as myself (who some say don't deserve to fly,
and maybe so...) might be tempted to get Daniel P. Raymer's book,
“Simplified Aircraft Design for Homebuilders” and take a stab at
designing something similar. (okay, not just this book but a whole bunch
of books, along with long visits to the FAA website.)

http://www.aircraftdesign.com/sadfh.html

I put into Raymer's spreadsheet a few things like 619 mile range, max
speed 160 mph, payload weight of 1190 lbs, wing taper ratio 1.0 and I
get a whopping gross weight of 4322 pounds, not the 3000 pounds of the
Murphy Moose. The engine suggested by the spreadsheet was also huge.

Well, that's a bit of a disconnect. I got similar disconnects when I
put in sizing data from other airplanes. The Raymer spreadsheet gives
much heavier designs. What's with that?

Q1) Is this because the Raymer book recommends overbuilding so that the
typical home designer doesn't have the engineering skill to make it lighter?

Q2) Are there any better books out there?

Please be kind. I'm a very sensitive fellow. (HA!)

[Bret Ludwig]

Stuart Grey wrote:
> I was looking at the design of the Murphy Moose:
>
> http://www.murphyair.com/
>
> They put the cost at about 100k$, cheap compared to the two Cessna's and
> the Bush Hawk to which Murphy compares the Moose:
>
> http://www.murphyair.com/Product_Info/Super/compare.htm
>
> From their engine page, half of that cost is probably engine.
>
> Empty weight is 1450 pounds.
>
> At Boeing surplus, a sheet of aluminum runs about $1.64/pound (Not
> including the Boeing discount). At 1450 pounds, that's only about $2400
> worth of aluminum. The rest is labor (they half build the airplane),
> mark up, insurance, support and so on. A really cheap guy who doesn't
> have a lot of money, such as myself (who some say don't deserve to fly,
> and maybe so...) might be tempted to get Daniel P. Raymer's book,
> "Simplified Aircraft Design for Homebuilders" and take a stab at
> designing something similar. (okay, not just this book but a whole bunch
> of books, along with long visits to the FAA website.)

I would buy a set of plans and use an existing design. I would
consider wood and fabric and steel tubing as well as aluminum. I would
shun certificated engines or else buy a used certified aircraft and
restore it.

Because most homebuilders today are affluent retirees and yuppies the
market has become cost-insensitive. Most designs popular today are
designed around the overpriced museum piece Lycoming engine because it
is faster and less hassle to use one.

I would leave airplane design alone until I had completed a couple of
other people's designs and done some college level coursework in
mechanical engineering or allied subjects. I have my own ideas on what
would be a good airplane but I know I'm not ready to do them yet.

[Stuart Grey]

Bret Ludwig wrote:
> Stuart Grey wrote:
>
>>I was looking at the design of the Murphy Moose:
>>
>>http://www.murphyair.com/
>>
>>They put the cost at about 100k$, cheap compared to the two Cessna's and
>>the Bush Hawk to which Murphy compares the Moose:
>>
>>http://www.murphyair.com/Product_Info/Super/compare.htm
>>
>> From their engine page, half of that cost is probably engine.
>>
>>Empty weight is 1450 pounds.
>>
>> At Boeing surplus, a sheet of aluminum runs about $1.64/pound (Not
>>including the Boeing discount). At 1450 pounds, that's only about $2400
>>worth of aluminum. The rest is labor (they half build the airplane),
>>mark up, insurance, support and so on. A really cheap guy who doesn't
>>have a lot of money, such as myself (who some say don't deserve to fly,
>>and maybe so...) might be tempted to get Daniel P. Raymer's book,
>>"Simplified Aircraft Design for Homebuilders" and take a stab at
>>designing something similar. (okay, not just this book but a whole bunch
>>of books, along with long visits to the FAA website.)
>
>
> I would buy a set of plans and use an existing design. I would
> consider wood and fabric and steel tubing as well as aluminum. I would
> shun certificated engines or else buy a used certified aircraft and
> restore it.
>
> Because most homebuilders today are affluent retirees and yuppies the
> market has become cost-insensitive. Most designs popular today are
> designed around the overpriced museum piece Lycoming engine because it
> is faster and less hassle to use one.
>
> I would leave airplane design alone until I had completed a couple of
> other people's designs and done some college level coursework in
> mechanical engineering or allied subjects. I have my own ideas on what
> would be a good airplane but I know I'm not ready to do them yet.

I think half the fun is doing the design. It is why I became an
engineer. :-) True, I'm just an electrical engineer, but I am familiar
with airplane design and certification to a small degree. I thought
about going back and getting an MS in Aero engineering, but you know,
desgrees are just for people who want to show to someone else who
doesn't know squat about the subject, so they'll give you a job. Anyone
with half a wit and the will can learn just about anything on their own.

So, what's the deal with Raymer's book? Does it have an excessive margin
of safty, or was I doing something wrong?

[Tater Schuld]

"Bret Ludwig" > wrote in message
ps.com...
>
> Because most homebuilders today are affluent retirees and yuppies the
> market has become cost-insensitive. Most designs popular today are
> designed around the overpriced museum piece Lycoming engine because it
> is faster and less hassle to use one.

or designed around over-rare VW engines that 20 years ago were in abundance

(till homebuilders got to them!)

[Marc J. Zeitlin]

Stuart Grey wrote:

> So, what's the deal with Raymer's book? Does it have an excessive
> margin of safty, or was I doing something wrong?

After playing with the spreadsheet for about 15 minutes, it looks as
though the weight calcs are VERY sensitive to a few parameters that
aren't well explained in the spreadsheet. Unless you know exactly what
those parameters are, I don't think you should trust the weight #'s that
you get. Maybe the book has in-depth explanations of what the
parameters are and how to set them.

--
Marc J. Zeitlin
http://www.cozybuilders.org/
Copyright (c) 2006

[Bret Ludwig]

Tater Schuld wrote:
> "Bret Ludwig" > wrote in message
> ps.com...
> >
> > Because most homebuilders today are affluent retirees and yuppies the
> > market has become cost-insensitive. Most designs popular today are
> > designed around the overpriced museum piece Lycoming engine because it
> > is faster and less hassle to use one.
>
> or designed around over-rare VW engines that 20 years ago were in abundance

They're still in abundance. Get a copy of the VW magazine and you can
see that there is a worldwide VW parts industry based around importing
VW parts from every country that makes them. All the hot rod stuff is
California.


The problem with the VW is it was never designed to directly turn a
prop and a direct drive VW combines every disadvantage of LyCon direct
drive engines with all those of the VW in the car, and more. A blower
cooled VW with redrive would work, but the general perception is, why
bother?


Homebuilt aircraft have no effect on non-aircraft parts prices they
use. Even if 100% of homebuilts used VW power there would still be 10
times as many aircooled VW cars licensed in Los Angeles County as
homebuilt airplanes nationwide. I have mentioned the 3.8 Javelin Ford
to junkyard operators and Ford mechanics over the last 20 years
probably 100 times and 99 of those they'd never heard of such a thing,
were amazed anyone would fly _that_ engine, or flat out didn't believe
me.

[Gerry Caron]

"Stuart Grey" > wrote in message
. ..
>
> I put into Raymer's spreadsheet a few things like 619 mile range, max
> speed 160 mph, payload weight of 1190 lbs, wing taper ratio 1.0 and I get
> a whopping gross weight of 4322 pounds, not the 3000 pounds of the Murphy
> Moose. The engine suggested by the spreadsheet was also huge.
>
> Well, that's a bit of a disconnect. I got similar disconnects when I put
> in sizing data from other airplanes. The Raymer spreadsheet gives much
> heavier designs. What's with that?
>
> Q1) Is this because the Raymer book recommends overbuilding so that the
> typical home designer doesn't have the engineering skill to make it
> lighter?
>
> Q2) Are there any better books out there?
>
> Please be kind. I'm a very sensitive fellow. (HA!)
>

I've only given Raymer's book a cursory look, but I wouldn't say he's overly
conservative. I do believe he assumes an effort to meet the intent, if not
the letter, of Part 23. That could introduce significantly more
"conservatism" than some kit makers have put into their designs. Would that
make up the difference you cite? Maybe, but probably not.

I expect a big factor in the difference is the basic assumptions made
regarding manufacturing materials and design. Aircraft design is a lesson
in compromise. Change one thing and it ripples thru affecting a dozen other
things. The fact is most a/c designs start out too heavy, too slow, and not
enough payload or performance.

Then the real work starts. Find a few little things to reduce drag. That
can give you a few extra knots or let you cut a few HP. Cut that HP and you
save structure and engine weight. With less to haul around, you can reduce
your fuel tanks and save some more weight or trade it for payload, and so
on...

I'd consider Raymer's numbers a starting point. The Murphy is one possible
end point. Give the same starting point to a Van or a Rutan, and you'll
have a different end point.

There are other books out there. They're different. Better is a very
subjective term.

Gerry

[Peter Dohm]

-----------much informative stuff snipped---------
> (till homebuilders got to them!)
>
Very true! Plus the ones that found their way into and onto dune buggies,
small airboats, old BMW motorcycles, and heaven knows what else. The same
problem is true of Corvair engines, of which I've even seem one mounted in
the bed of a pick-up truck and driving an electric generator. The BMW 600
and 700 automobiles were never popular enough to have single seat aircraft
designed around them, at least in the US, and the little air cooled Subaru
engines were probably gone from the stock-piles before the Part 103
ultralight rule allowed 254 pounds empty. I suspect that the BMW and Soob
engines would have been chosen over the 1/2VW if availability permitted.

[Bret Ludwig]

Peter Dohm wrote:
> -----------much informative stuff snipped---------
> > (till homebuilders got to them!)
> >
> Very true! Plus the ones that found their way into and onto dune buggies,
> small airboats, old BMW motorcycles, and heaven knows what else. The same
> problem is true of Corvair engines, of which I've even seem one mounted in
> the bed of a pick-up truck and driving an electric generator. The BMW 600
> and 700 automobiles were never popular enough to have single seat aircraft
> designed around them, at least in the US, and the little air cooled Subaru
> engines were probably gone from the stock-piles before the Part 103
> ultralight rule allowed 254 pounds empty. I suspect that the BMW and Soob
> engines would have been chosen over the 1/2VW if availability permitted.



Nope.

The nonautomotive uses of VWs-the most creative was probably the 2
cylinder integral air compressor-and dune buggy building made only the
smallest dent in VW supplies. They sold probably fifteen million
aircooled VWs in this country and probably fifty thousand dune buggies
were the high point.

The BMW 600 and 700 used BMW motorcycle engine cores and the bikes
were far more popular.

The Citroen 2CV twins and GS fours were used in homebuilt airplanes
and kit bikes in Europe. Same deal.

Corvairs have probably had the highest percentage of predation along
with the 215 aluminum GM V8 but in both cases more have been summarilyy
scrapped than all hobby uses combined. Corvairs are still not
scarce-any old smallblock brings more money most of the time.

[Richard Lamb]

Just as a friendly challenge to anyone foolish enough...

Design an airplane within the 254 pound weight limit.

Clean sheet of paper.
254 pounds empty weight.
Your choice of engines, design, materials.

Where would you start?

Richard

[Ben Hallert]

> Just as a friendly challenge to anyone foolish enough...
> Design an airplane within the 254 pound weight limit.

IFR or not? Does it have to be able to fly into known icing?

:)

Ben Hallert
PP-ASEL - http://hallert.net/cozy/

[Richard Lamb]

Ben Hallert wrote:

>>Just as a friendly challenge to anyone foolish enough...
>>Design an airplane within the 254 pound weight limit.
>
>
> IFR or not? Does it have to be able to fly into known icing?
>
> :)
>
> Ben Hallert
> PP-ASEL - http://hallert.net/cozy/
>

Uh, no.

And day VFR seams more reasonable.
Although I do love flying at night...

[Montblack]

("Richard Lamb" wrote)
> Design an airplane within the 254 pound weight limit.
>
> Clean sheet of paper.
> 254 pounds empty weight.
> Your choice of engines, design, materials.
>
> Where would you start?


Cri-Cri type
Twin diesels - torque, torque, torque
Wings that rock - "control wing" "free wing"

<http://www.flyingflea.org/docs/SprattControlwing.htm>

<http://www.airandspacemagazine.com/ASM/Mag/Index/1995/DJ/ssfw.html>

Original CriCri's weighed approx 150lbs, that included two 9hp engines. 150
lbs - total!

150 lbs - (15# engine + 15# engine) = 120 lbs - 20 lbs other stuff = 100 lbs
of plane building material.

So I'm thinking ...how much would (guessing) 60lbs of Titanium cost?


Montblackium

[ChuckSlusarczyk]

In article et>, Richard Lamb
says...
>
>Just as a friendly challenge to anyone foolish enough...
>
>Design an airplane within the 254 pound weight limit.
>
>Clean sheet of paper.
>254 pounds empty weight.
>Your choice of engines, design, materials.
>
>Where would you start?

I for one have done it www.cgsaviation.com/hawkultra.htm and so have
others.Mine not also meets the 254 # but the stall speed and top speed criteria
set by the feds in part 103-7. Although I don't think this is the style of plane
the original questioner had in mind. Weight is relative and on this end of the
spectrum alum sheet gets heavy as a build material.Especially if it's over .020.

The Hummel plane is all alum and can carry a 200# guy has a fairly good sized
wing, so it's not a rocket at landing.But it still tips the scales at almost
300# empty.

It's an interesting challenge something us Ultralight guys have had to work with
for about 25 years. One thing I did was to not design to the 170# FAA pilot
since most pilots I know and and those I see at airshows haven't been 170# since
8th grade ,that includes me as well :-)So your design should use 200# -220# for
the design criteria. Good luck.

See ya

Chuck S

[Richard Lamb]

ChuckSlusarczyk wrote:
> In article et>, Richard Lamb
> says...
>
>>Just as a friendly challenge to anyone foolish enough...
>>
>>Design an airplane within the 254 pound weight limit.
>>
>>Clean sheet of paper.
>>254 pounds empty weight.
>>Your choice of engines, design, materials.
>>
>>Where would you start?
>
>
> I for one have done it www.cgsaviation.com/hawkultra.htm and so have
> others.Mine not also meets the 254 # but the stall speed and top speed criteria
> set by the feds in part 103-7. Although I don't think this is the style of plane
> the original questioner had in mind. Weight is relative and on this end of the
> spectrum alum sheet gets heavy as a build material.Especially if it's over .020.
>
> The Hummel plane is all alum and can carry a 200# guy has a fairly good sized
> wing, so it's not a rocket at landing.But it still tips the scales at almost
> 300# empty.
>
> It's an interesting challenge something us Ultralight guys have had to work with
> for about 25 years. One thing I did was to not design to the 170# FAA pilot
> since most pilots I know and and those I see at airshows haven't been 170# since
> 8th grade ,that includes me as well :-)So your design should use 200# -220# for
> the design criteria. Good luck.
>
> See ya
>
> Chuck S
>
Hey Chuck,

I've seen those around. There are two or three at Kitty Hawk.
Guess I'll go visit and see how they fly!

Richard

[Anthony W]

Richard Lamb wrote:
> ChuckSlusarczyk wrote:
>
>> In article et>,
>> Richard Lamb
>> says...
>>
>>> Just as a friendly challenge to anyone foolish enough...
>>>
>>> Design an airplane within the 254 pound weight limit.
>>>
>>> Clean sheet of paper.
>>> 254 pounds empty weight.
>>> Your choice of engines, design, materials.
>>>
>>> Where would you start?
>>
>>
>>
>> I for one have done it www.cgsaviation.com/hawkultra.htm and so have
>> others.Mine not also meets the 254 # but the stall speed and top speed
>> criteria
>> set by the feds in part 103-7. Although I don't think this is the
>> style of plane
>> the original questioner had in mind. Weight is relative and on this
>> end of the
>> spectrum alum sheet gets heavy as a build material.Especially if it's
>> over .020.
>>
>> The Hummel plane is all alum and can carry a 200# guy has a fairly
>> good sized
>> wing, so it's not a rocket at landing.But it still tips the scales at
>> almost
>> 300# empty.
>>
>> It's an interesting challenge something us Ultralight guys have had to
>> work with
>> for about 25 years. One thing I did was to not design to the 170# FAA
>> pilot
>> since most pilots I know and and those I see at airshows haven't been
>> 170# since
>> 8th grade ,that includes me as well :-)So your design should use 200#
>> -220# for
>> the design criteria. Good luck.
>>
>> See ya
>> Chuck S
>>
> Hey Chuck,
>
> I've seen those around. There are two or three at Kitty Hawk.
> Guess I'll go visit and see how they fly!
>
> Richard


There's a volcanolgist in Iceland that has been flying one over some
pretty dangerous ground for for the past few years. By all accounts it
a good plane but he but have titanium balls to fly any ultralight over a
volcano...

[Jim Carriere]

Ben Hallert wrote:
>> Just as a friendly challenge to anyone foolish enough...
>> Design an airplane within the 254 pound weight limit.
>
> IFR or not? Does it have to be able to fly into known icing?
>
> :)

LOL! Pressurized? Retractable gear?

[wright1902glider]

The only thing stopping me from hanging tricycle gear and a pair of
JetCat 200 turbojets off my Wright machine is the $10k+ cost of the
engines. Supose I could just use a pair of chainsaw motors... or even
6 model airplane engines, but that wouldn't be nearly as cool. By
Wilbur's calcs, the 1902 glider only requires 6 hp at 30 kts cruise.
Stall is at 14, and Vne is about 50 kts. Of course it'll still fly
like crap compared to a modern UL, but then the design is 104 years
old.

Harry

[Stuart Grey]

Marc J. Zeitlin wrote:
> Stuart Grey wrote:
>
>
>>So, what's the deal with Raymer's book? Does it have an excessive
>>margin of safty, or was I doing something wrong?
>
>
> After playing with the spreadsheet for about 15 minutes, it looks as
> though the weight calcs are VERY sensitive to a few parameters that
> aren't well explained in the spreadsheet. Unless you know exactly what
> those parameters are, I don't think you should trust the weight #'s that
> you get. Maybe the book has in-depth explanations of what the
> parameters are and how to set them.

Yes, I needed to understand the parameters, and they were explained
better later in the book.. The book is kind of pricy for the number of
pages, but on the other hand, it gets to the core of what you need to
know without a lot of (unnecessary) theory and explaination, so you're
getting good bang for the buck. I can relate to that.

My problem came from the parameter "a". The book gives 1.19 for a single
engine, metal design - and this is the paramter I used. Way in the back
of the book, on page 135 (yeah, it's not a thick book) it shows how the
parameter a is calculated. You should find similar planes to the one you
want to build, and find the ratio of their empty weight to fully loaded
weight, and graph that on a chart against the fully loaded weight.

Among home built planes, there is a large cluster near 0.6-0.65 for
We/Wo, resulting in an a of over 1.2. However, there is another cluster
near 0.45 to 0.59 that result in an a closer to an a of 1.0 or below. I
think the airplane I want to build is in this grouping and not the
other. I suspect the difference is the smaller grouping is a high wing
with struts, while the other grouping is a low strutless wing.

It appears to be worthwhile to read the entire book. :-) Doh!

[Stuart Grey]

Gerry Caron wrote:
> "Stuart Grey" > wrote in message
> . ..
>
>>I put into Raymer's spreadsheet a few things like 619 mile range, max
>>speed 160 mph, payload weight of 1190 lbs, wing taper ratio 1.0 and I get
>>a whopping gross weight of 4322 pounds, not the 3000 pounds of the Murphy
>>Moose. The engine suggested by the spreadsheet was also huge.
>>
>>Well, that's a bit of a disconnect. I got similar disconnects when I put
>>in sizing data from other airplanes. The Raymer spreadsheet gives much
>>heavier designs. What's with that?
>>
>>Q1) Is this because the Raymer book recommends overbuilding so that the
>>typical home designer doesn't have the engineering skill to make it
>>lighter?
>>
>>Q2) Are there any better books out there?
>>
>>Please be kind. I'm a very sensitive fellow. (HA!)
>>
>
>
> I've only given Raymer's book a cursory look, but I wouldn't say he's overly
> conservative. I do believe he assumes an effort to meet the intent, if not
> the letter, of Part 23. That could introduce significantly more
> "conservatism" than some kit makers have put into their designs. Would that
> make up the difference you cite? Maybe, but probably not.
>
> I expect a big factor in the difference is the basic assumptions made
> regarding manufacturing materials and design. Aircraft design is a lesson
> in compromise. Change one thing and it ripples thru affecting a dozen other
> things. The fact is most a/c designs start out too heavy, too slow, and not
> enough payload or performance.
>
> Then the real work starts. Find a few little things to reduce drag. That
> can give you a few extra knots or let you cut a few HP. Cut that HP and you
> save structure and engine weight. With less to haul around, you can reduce
> your fuel tanks and save some more weight or trade it for payload, and so
> on...
>
> I'd consider Raymer's numbers a starting point. The Murphy is one possible
> end point. Give the same starting point to a Van or a Rutan, and you'll
> have a different end point.
>
> There are other books out there. They're different. Better is a very
> subjective term.
>
> Gerry


It's interesting in that the methods used are based on existing designs
for a rough estimate. If you use the wrong class of airplanes for your
parameter selection, you don't get the numbers you expect. My problem
was that I used a parameter that was not close to the type of plane I
was targeting.

Aircraft design seems to be an iterative process; you guess the weight,
design to a given weight, look at how much the structure weighs, and
then try again. You can't design the structure without knowing the
weight, you don't know how much the structure weighs until you design
it. Chicken and egg thing. For this reason, they use regression analysis
of existing working designs.

[Marc J. Zeitlin]

Stuart Grey wrote:

> Aircraft design seems to be an iterative process.....
> Chicken and egg thing. For this reason, they use regression analysis
> of existing working designs.

Correct. This is a good thing, if you know what you're doing, because
it lets you easily determine what a new airplane is going to look like,
weigh, etc. On the other hand, you never get breakthroughs by using
this method, since whatever you design will be very similar to what's
come before.

I have found, since I started working at Scaled last September, that we
use a mix of "do it just like that" and "don't do it anything like
that", depending upon need :-).

--
Marc J. Zeitlin
http://www.cozybuilders.org/
Copyright (c) 2006

[Morgans]

"Marc J. Zeitlin" > wrote
>
> I have found, since I started working at Scaled last September, that we
> use a mix of "do it just like that" and "don't do it anything like that",
> depending upon need :-).
\
Cool stuff going on at Scaled; I would love to be qualified, and to get a
chance to work there.

I know you have posted what you do there, but I have forgotten. What is it,
again, if you would?

That philosophy you posted above, about says it all, huh? <g>
--
Jim in NC

[Marc J. Zeitlin]

Morgans wrote:

> I know you have posted what you do there, but I have forgotten.
> What is it, again, if you would?

I don't think that I have - maybe you're confusing me with someone else,
but I don't know who that might be - Scaled is not a big place :-).

I'm a mechanical/aeronautical engineer. I design stuff. Sometimes I
build it, too, and test it :-).

--
Marc J. Zeitlin
http://www.cozybuilders.org/
Copyright (c) 2006

[Stealth Pilot]

On Thu, 02 Feb 2006 06:08:14 GMT, "Marc J. Zeitlin"
> wrote:

>Morgans wrote:
>
>> I know you have posted what you do there, but I have forgotten.
>> What is it, again, if you would?
>
>I don't think that I have - maybe you're confusing me with someone else,
>but I don't know who that might be - Scaled is not a big place :-).
>
>I'm a mechanical/aeronautical engineer. I design stuff. Sometimes I
>build it, too, and test it :-).

mark is the isolation of the mojave desert one of rutan's best aids to
invention?
if he worked in the bustle of LA, for instance, do you think he'd be
anywhere near as innovative or productive?

me, I just love working in my workshop without any television in
earshot.

Stealth Pilot

[.Blueskies.]

"Marc J. Zeitlin" > wrote in message ...
>
> I don't think that I have - maybe you're confusing me with someone else, but I don't know who that might be - Scaled
> is not a big place :-).
>
> I'm a mechanical/aeronautical engineer. I design stuff. Sometimes I build it, too, and test it :-).
>
> --
> Marc J. Zeitlin
> http://www.cozybuilders.org/
> Copyright (c) 2006
>

Stuff is cool, unless superheated, then it is steam?

--
Dan DeVillers
http://www.ameritech.net/users/ddevillers/start.html


..

[Morgans]

> I don't think that I have - maybe you're confusing me with someone else,
> but I don't know who that might be - Scaled is not a big place :-).
>
> I'm a mechanical/aeronautical engineer. I design stuff. Sometimes I
> build it, too, and test it :-).

Cool! What projects have you had a hand in? Some of the "big" ones?

I love all the innovation that has come out of Scaled. Being close to White
Knight and Space One definitely will go down on the list of things that will
stay with me for a long time.

I am not a mechanical engineer, but had I gotten a better start with math
while in Jr. High and High School, I might have been one. I was in the "new
math" debacle. My dad was a M.E., and he taught me many things of the
mechanical world. I like nothing better than getting an idea, coming up
with a solution, then building the device, or system, or whatever, and
seeing it work, as I pictured it in my mind's eye. I would like nothing
better than designing and building my own plane, but I'm a bit away from
seeing that happen.
--
Jim in NC

[Richard Lamb]

Marc J. Zeitlin wrote:
> Morgans wrote:
>
>
>>I know you have posted what you do there, but I have forgotten.
>>What is it, again, if you would?
>
>
> I don't think that I have - maybe you're confusing me with someone else,
> but I don't know who that might be - Scaled is not a big place :-).
>
> I'm a mechanical/aeronautical engineer. I design stuff. Sometimes I
> build it, too, and test it :-).
>

I know he won't remember me, but I got to work with Burt at Bede way back
when. I made a honeycomb-paper-core/Glass/Epoxy I-Beam sample for him, but
he already had foam on his mind. I didn't understand it then, but the trade
off between weight and work was obviously the right one.

Tell him "Hi", and "WoW!!!" for me, will ya?


Richard

[Stealth Pilot]

On Thu, 2 Feb 2006 19:20:18 -0500, "Morgans"
> wrote:

>
>> I don't think that I have - maybe you're confusing me with someone else,
>> but I don't know who that might be - Scaled is not a big place :-).
>>
>> I'm a mechanical/aeronautical engineer. I design stuff. Sometimes I
>> build it, too, and test it :-).
>
>Cool! What projects have you had a hand in? Some of the "big" ones?
>
>I love all the innovation that has come out of Scaled. Being close to White
>Knight and Space One definitely will go down on the list of things that will
>stay with me for a long time.
>
>I am not a mechanical engineer, but had I gotten a better start with math
>while in Jr. High and High School, I might have been one. I was in the "new
>math" debacle. My dad was a M.E., and he taught me many things of the
>mechanical world. I like nothing better than getting an idea, coming up
>with a solution, then building the device, or system, or whatever, and
>seeing it work, as I pictured it in my mind's eye. I would like nothing
>better than designing and building my own plane, but I'm a bit away from
>seeing that happen.

Jim you are only limited by your self doubt. I admit it is hard to
find decent aero engineering references that are understandable but
keep trying. we'll both get there one day.

Stealth Pilot

[Stuart Grey]

Montblack wrote:
> ("Richard Lamb" wrote)
>
>> Design an airplane within the 254 pound weight limit.
>>
>> Clean sheet of paper.
>> 254 pounds empty weight.
>> Your choice of engines, design, materials.
>>
>> Where would you start?
>
>
>
> Cri-Cri type
> Twin diesels - torque, torque, torque
> Wings that rock - "control wing" "free wing"
>
> <http://www.flyingflea.org/docs/SprattControlwing.htm>
>
> <http://www.airandspacemagazine.com/ASM/Mag/Index/1995/DJ/ssfw.html>
>
> Original CriCri's weighed approx 150lbs, that included two 9hp engines.
> 150 lbs - total!
>
> 150 lbs - (15# engine + 15# engine) = 120 lbs - 20 lbs other stuff = 100
> lbs of plane building material.
>
> So I'm thinking ...how much would (guessing) 60lbs of Titanium cost?
>
>
> Montblackium


So, why did they put two engines on that small of of an airplane?
Was it to get around the 61 kts stall speed requirement? (I believe two
engine airplanes don't need to meet that...) Or was it just because they
could?

[Morgans]

"Stealth Pilot" > wrote

> I admit it is hard to
> find decent aero engineering references that are understandable but
> keep trying. we'll both get there one day.
\
Of that, I have no doubt. <g>
--
Jim in NC

[Peter Dohm]

"Stuart Grey" > wrote in message
...
> Montblack wrote:
> > ("Richard Lamb" wrote)
> >
> >> Design an airplane within the 254 pound weight limit.
> >>
> >> Clean sheet of paper.
> >> 254 pounds empty weight.
> >> Your choice of engines, design, materials.
> >>
> >> Where would you start?
> >
> >
> >
> > Cri-Cri type
> > Twin diesels - torque, torque, torque
> > Wings that rock - "control wing" "free wing"
> >
> > <http://www.flyingflea.org/docs/SprattControlwing.htm>
> >
> > <http://www.airandspacemagazine.com/ASM/Mag/Index/1995/DJ/ssfw.html>
> >
> > Original CriCri's weighed approx 150lbs, that included two 9hp engines.
> > 150 lbs - total!
> >
> > 150 lbs - (15# engine + 15# engine) = 120 lbs - 20 lbs other stuff = 100
> > lbs of plane building material.
> >
> > So I'm thinking ...how much would (guessing) 60lbs of Titanium cost?
> >
> >
> > Montblackium
>
>
> So, why did they put two engines on that small of of an airplane?
> Was it to get around the 61 kts stall speed requirement? (I believe two
> engine airplanes don't need to meet that...) Or was it just because they
> could?
>
I really don't know either. But it is a pretty old design, so it is
possible that the designed was simply not aware of a suitable single engine
at the time. It is also possible that there was concern about the fuselage
reducing the thrust of a very small prop--the props do operate in relatively
undisturbed air and have plenty of clear space behind them.

To the best of my recollection, the designer really was an aeronautical
engineer--which I am not.

Peter

[Robert Dorsey]

Pick up what many believe to be the bible of aircraft design,
"Analysis & Design of Flight Vehicle Structures" by Bruhn. Should be
available in big libraries or ebay. It has many worked examples in
each section.
Bob



On Fri, 03 Feb 2006 20:58:01 +0800, Stealth Pilot
> wrote:


>
>Jim you are only limited by your self doubt. I admit it is hard to
>find decent aero engineering references that are understandable but
>keep trying. we'll both get there one day.
>
>Stealth Pilot

[Marc J. Zeitlin]

Stealth Pilot wrote:

> mark is the isolation of the mojave desert one of rutan's best aids to
> invention?

That's an interesting question. I hadn't thought about it. To tell you
the truth, I don't think so - he does a lot of traveling; there are
always folks coming in for visits, and I think that he's one of those
guys that would be productive/inventive locked in a box on the top of
Mt. Everest, or stuck in the middle of Manhattan. And while Mojave is
small, I wouldn't call it isolated (and I say that as someone that grew
up in NY and lived in Boston for 30 years).

> if he worked in the bustle of LA, for instance, do you think he'd be
> anywhere near as innovative or productive?

Yeah. I don't think it would matter :-).

> me, I just love working in my workshop without any television in
> earshot.

Agreed, although when I was building my Q2, I had the radio on full
blast all the time, either rock or news. However, building the COZY, I
liked it quiet.

--
Marc J. Zeitlin
http://www.cozybuilders.org/
Copyright (c) 2006

[Marc J. Zeitlin]

Morgans

> Cool! What projects have you had a hand in? Some of the "big" ones?

Well, I just started there in September, so I've been working on a
number of small things, to get my feet wet and learn the ropes, so to
speak. I do have some responsibility for some of the systems on SS2,
and I've designed, built, and tested some "poor man's wind tunnel"
apparatus that's mounted on the front of a F-250 truck. If you happen
to get the Mojave News (I THINK that's the name of the paper), there'll
be a picture of the setup in there next week - a van pulled up to me
today after I was racing down the runway, and a guy took some pictures
(with permission, apparently) :-).

--
Marc J. Zeitlin
http://www.cozybuilders.org/
Copyright (c) 2006

[Richard Lamb]

Marc J. Zeitlin wrote:

> Morgans
>
>
>>Cool! What projects have you had a hand in? Some of the "big" ones?
>
>
> Well, I just started there in September, so I've been working on a
> number of small things, to get my feet wet and learn the ropes, so to
> speak. I do have some responsibility for some of the systems on SS2,
> and I've designed, built, and tested some "poor man's wind tunnel"
> apparatus that's mounted on the front of a F-250 truck. If you happen
> to get the Mojave News (I THINK that's the name of the paper), there'll
> be a picture of the setup in there next week - a van pulled up to me
> today after I was racing down the runway, and a guy took some pictures
> (with permission, apparently) :-).
>

Probably a 21st Century version of the one on top of the station wagon?

[Marc J. Zeitlin]

Richard Lamb wrote:

> Probably a 21st Century version of the one on top of the station
> wagon?

If you call an F-250 and a bunch of 2" square steel tubing 21st century.
Let's go with 1980's :-).

--
Marc J. Zeitlin
http://www.cozybuilders.org/
Copyright (c) 2006

[Stuart Grey]

Peter Dohm wrote:
> "Stuart Grey" > wrote in message
> ...
>
>>Montblack wrote:
>>
>>>("Richard Lamb" wrote)
>>>
>>>
>>>>Design an airplane within the 254 pound weight limit.
>>>>
>>>>Clean sheet of paper.
>>>>254 pounds empty weight.
>>>>Your choice of engines, design, materials.
>>>>
>>>>Where would you start?
>>>
>>>
>>>
>>>Cri-Cri type
>>>Twin diesels - torque, torque, torque
>>>Wings that rock - "control wing" "free wing"
>>>
>>><http://www.flyingflea.org/docs/SprattControlwing.htm>
>>>
>>><http://www.airandspacemagazine.com/ASM/Mag/Index/1995/DJ/ssfw.html>
>>>
>>>Original CriCri's weighed approx 150lbs, that included two 9hp engines.
>>>150 lbs - total!
>>>
>>>150 lbs - (15# engine + 15# engine) = 120 lbs - 20 lbs other stuff = 100
>>>lbs of plane building material.
>>>
>>>So I'm thinking ...how much would (guessing) 60lbs of Titanium cost?
>>>
>>>
>>>Montblackium
>>
>>
>>So, why did they put two engines on that small of of an airplane?
>>Was it to get around the 61 kts stall speed requirement? (I believe two
>>engine airplanes don't need to meet that...) Or was it just because they
>>could?
>>
>
> I really don't know either. But it is a pretty old design, so it is
> possible that the designed was simply not aware of a suitable single engine
> at the time. It is also possible that there was concern about the fuselage
> reducing the thrust of a very small prop--the props do operate in relatively
> undisturbed air and have plenty of clear space behind them.
>
> To the best of my recollection, the designer really was an aeronautical
> engineer--which I am not.
>
> Peter

I have to admit, it looks cool.

[Richard Lamb]

Marc J. Zeitlin wrote:

> Richard Lamb wrote:
>
>
>>Probably a 21st Century version of the one on top of the station
>>wagon?
>
>
> If you call an F-250 and a bunch of 2" square steel tubing 21st century.
> Let's go with 1980's :-).
>

OH! Well, actually I was thinking of the electronics.
The origonal usea a lot of 10 turn pots, cables and stuff.

I'd ASSuME that at least taht part is a little more "solid state"?


Richard

[Marc J. Zeitlin]

Richard Lamb wrote:

> OH! Well, actually I was thinking of the electronics.
> The origonal usea a lot of 10 turn pots, cables and stuff.
>
> I'd ASSuME that at least taht part is a little more "solid state"?

We've got a pitot/static tube with an electronic output, an "alpha" and
"beta" vane, each on a low friction potentiometer, and a load cell.
These all feed into a A-D converter, which talks to DasyLab on a laptop
in the cab.

So, maybe 1990's there :-). We use what we have, and what works. If we
NEEDED something fancier, we'd get it.

--
Marc J. Zeitlin
http://www.cozybuilders.org/
Copyright (c) 2006

[Highflyer]

"Stealth Pilot" > wrote in message
...

> mark is the isolation of the mojave desert one of rutan's best aids to
> invention?
> if he worked in the bustle of LA, for instance, do you think he'd be
> anywhere near as innovative or productive?
>
> me, I just love working in my workshop without any television in
> earshot.
>
> Stealth Pilot

When Burt was working at Micky D at Lambert Field in St. Louis he was still
creative. I recall he mounted a large scale model of one of his designs,
the VariViggen I believe, on the hood of an old beater car and drove it at
appropriate speeds up and down the runway at the airport in St. Charles, Mo,
to do his wind tunnel work! I thought that was pretty darned creative!

Highflyer
Highflight Aviation Services
Pinckneyville Airport ( PJY )

PS: The Pinckneyville Flyin is coming up, May 19, 20, and 21. Time to
start planning. Let Mary know you are coming at or there
may not be any food for you! :-)