Airplane design.

"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

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

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

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

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?

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

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.

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

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

"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! :-)