Have you guys ever noticed the void?

On Tue, 10 Jan 2006 11:24:24 GMT, Matt Whiting wrote:

Ron Wanttaja wrote:

I have to admit he does bring up a good point. I have often wondered
what the difference in strength's and weakness would be if I used
different wood in my plane, or enlarged the components for a larger
pilot.


Which is probably one reasons designers don't provide the equations. Many hate
it when folks make changes.

Most equations for light airplane design are well established and have
been around for decades. What unique equations could a typical designer
provide?

Not the equations per se, but the precise values and the design margins of the
design in question, the non-designer's lack of understanding of the
interrelationships between design elements, and the legal implications of
*providing* the information.

Remember, the poster I responded to specifically referred to the substitution of
one material for another. It's sometimes more than a mere comparison of the
strengths of the materials.

Ron Wanttaja

On Mon, 09 Jan 2006 18:43:22 -0800, Ron Wanttaja
wrote:

On 9 Jan 2006 12:16:29 -0800, "Lou" wrote:

I have to admit he does bring up a good point. I have often wondered
what the difference in strength's and weakness would be if I used
different wood in my plane, or enlarged the components for a larger
pilot.

Which is probably one reasons designers don't provide the equations. Many hate
it when folks make changes.

Ron Wanttaja

your honour I sold the guy the plans, I provided him with the worked
design calculations showing how the design was arrived at. the
comments in the calculations show how the material sizes were arrived
at. he has made changes to the aircraft which are neither in the
original designs nor show any validating calculations so my conclusion
is that he just guessed at the changes and proceeded blindly.
I cannot see how I can be held responsible for the stupidly
incompetent actions of others.

sounds like a defense to me.

Stealth Pilot

Stealth Pilot wrote:


your honour I sold the guy the plans, I provided him with the worked
design calculations showing how the design was arrived at. the
comments in the calculations show how the material sizes were arrived
at. he has made changes to the aircraft which are neither in the
original designs nor show any validating calculations so my conclusion
is that he just guessed at the changes and proceeded blindly.
I cannot see how I can be held responsible for the stupidly
incompetent actions of others.

sounds like a defense to me.

Stealth Pilot

Don't get me wrong, Stealth, I hear what you are saying.

But I think the kind of analysis you imply is beyond anybody
but Boeing (even Airbus seems to have problems getting it right).


Igor Sikorsky was quoted as saying:

There are good designers with good designs and
good designers with bad designs,

And there are bad designers with good designs
and bad designers with bad designs.

If all designers flew their own designs, there would
eventually be only good designers with good designs.


A little old Russian arrogance, but an interesting point.

On Wed, 11 Jan 2006 22:08:05 +0800, Stealth Pilot wrote:

On Mon, 09 Jan 2006 18:43:22 -0800, Ron Wanttaja
wrote:

On 9 Jan 2006 12:16:29 -0800, "Lou" wrote:

I have to admit he does bring up a good point. I have often wondered
what the difference in strength's and weakness would be if I used
different wood in my plane, or enlarged the components for a larger
pilot.

Which is probably one reasons designers don't provide the equations. Many hate
it when folks make changes.

your honour I sold the guy the plans, I provided him with the worked
design calculations showing how the design was arrived at. the
comments in the calculations show how the material sizes were arrived
at. he has made changes to the aircraft which are neither in the
original designs nor show any validating calculations so my conclusion
is that he just guessed at the changes and proceeded blindly.
I cannot see how I can be held responsible for the stupidly
incompetent actions of others.

sounds like a defense to me.

And by the time you get to tell your side of the story to the judge, you're out
$20,000 or so in attorney's fees. Burt Rutan never lost a lawsuit...but he got
tired of defending himself and got out of the homebuilt business twenty years
ago. One homebuilt company in the '80s was destroyed defending itself against a
suit where the customer drilled into his engine case to install a gauge but
didn't bother to remove the metal chips. They won the case...but went bankrupt
doing so.

Ron Wanttaja

"Stealth Pilot" wrote in message
...
On Mon, 09 Jan 2006 18:43:22 -0800, Ron Wanttaja
wrote:

On 9 Jan 2006 12:16:29 -0800, "Lou" wrote:

I have to admit he does bring up a good point. I have often wondered
what the difference in strength's and weakness would be if I used
different wood in my plane, or enlarged the components for a larger
pilot.

Which is probably one reasons designers don't provide the equations. Many
hate
it when folks make changes.

Ron Wanttaja

your honour I sold the guy the plans, I provided him with the worked
design calculations showing how the design was arrived at. the
comments in the calculations show how the material sizes were arrived
at. he has made changes to the aircraft which are neither in the
original designs nor show any validating calculations so my conclusion
is that he just guessed at the changes and proceeded blindly.
I cannot see how I can be held responsible for the stupidly
incompetent actions of others.

sounds like a defense to me.

Stealth Pilot

Sorry. In our courts you are not held responsible for the stupidly
incompetent actions of others. However, if their stupid incompetent act
hurts someone and you have lots of money or they THINK you have lots of
money you ARE held responsible. For example, a fellow flew his Beech
Debonair into a mountain. When he hit the mountain a fuel line broke and
the wreck caught fire. Continental lost the suit for something like 100
million in punitive damages for building engines with fuel lines that can
break when you fly into a mountain. Incidently the lawyer who did the song
and dance for the jury to win that award was almost incinerated himself when
he crashed the jet he bought with his proceeds on takeoff and it caught
fire.

Highflyer
Highflight Aviation Services
Pinckneyville Airport ( PJY )

On 9 Jan 2006 12:05:59 -0800, wrote:


So fill the void yourself. Slide rule, #2 yaller pencil and the back
of an envelop, you're half way there. (You may use a calculator, if
you wish.)

I'm in the process of doing exactly that. ...and beyond that trying to
get a book written targetted to the amateur designer.

The other half has to do with the basic purpose of the 'Experimental -
Amateur Built' licensing category, in that it exists to foster
aeronautical education, which implies the need to know what you're
doing, if not from the outset, at least before first-flight.

the weakness in the argument is that there is no way for someone
learning to verify their calculations.
the absolute absence of calculations available for learning or
developing from means that while our building skills and confidence
may be in the second century of aviation our design skills are right
back there with the wright brothers.

And if that sounds slightly fey, as I'm sure it will to most of the
kit-assemblers, consider the other side of the coin: If the designer
provided you with detailed data, how would you know they were correct
without duplicating his calculations?

my point exactly. I want to verify the calculations. the aircraft I am
building is aerobatted by some and declared by others to have a 3.8g
ultimate wing. only access to the designers numbers will allow me to
sort the bs from the advertised claims and see what the actual
situation was when designed and now.

Even then, weight -- that is,
ACTUAL weight -- is a critical factor in those calculations. A lot of
home-builts were designed by midgets for others of their kind and often
cite weights and g-factors that are wildly fallacious if not out-right
lies. Stuff a two hundred fifty pound lard-ass in the cockpit, use
real numbers and the calculations for some of the most popular designs
are liable to read 'Lawn Dart.'

again if the original calculations were available the folly would be
easy to establish by running the calculations with the actual weight
against the design strengths.

Expecting the EAA to do something about your 'void' is wishful
thinking, in my opinion.

the eaa dont design aircraft. this is something that the eaa cant do.
this is however something that each and every designer can assist in
easily. I think that this black void in the homebuilding area actually
covers up a lot of ignorance. while it is easy to pretend that you
understand, in very many cases I have found that fear of ridicule is
behind keeping what calculations have been made secret.
we need to modify our environment to make the publication of design
calcs a part of creating a design. that way we will develop more
competent design knowledge in the community.

come to think of it the eaa I'm sure would be more than happy to add a
section to the members area to hold sets of design calcs.

I suggest the wiser course is to think for yourself If that requires
cracking a few books on airframe structural analysis, so be it. (Try a
search using 'fundamentals of aircraft structural analysis.' The books
are out there and fairly cheap, too -- apparently because nobody reads
them :-)
and all you get from that is a guessed set of figures which tell you
nothing about the oversights in design or the plain errors in
calculation that have crept through.
the design book that I was working through yesterday(Vogel) turns out
to have pages of stuffed up calculations in it. I learnt a lot from
working out that there must have been errors and correcting them but I
could have learnt far more with some valid example calcs to work
through.

if we are not to repeat all the mistakes and inefficiencies of the
last century of aviation, ie to progress to really efficient
homebuilts in the future, we really need to get the designs and the
calculations discussed not the bloody paint schemes.

think also on the consequences for safety. would all those guys have
died aerobatting in RV3's for instance if they had been able to see
the calcs for themselves? ...and to see how close they were pushing
it.
Stealth (working on it and I'm eaa712250 ) Pilot

Stealth Pilot wrote:
(veeduber wrote
And if that sounds slightly fey, as I'm sure it will to most of the
kit-assemblers, consider the other side of the coin: If the designer
provided you with detailed data, how would you know they were correct
without duplicating his calculations?

my point exactly. I want to verify the calculations.
--------------------------------------------------------------------------------------

Then flip that puppy over and start stacking on the cement sacks.

--------------------------------------------------------------------------------------

the aircraft I am
building is aerobatted by some and declared by others to have a 3.8g
ultimate wing. only access to the designers numbers will allow me to
sort the bs from the advertised claims and see what the actual
situation was when designed and now.

--------------------------------------------------------------------------------------

Well... I hate to tell you this but the numbers alone won't give you
the Ultimate Answer. Load it to the max, turn it inside out whilst
upside down and you're liable to fail some itsy-bitsy part that was
never included in the calculations... but causes the wing to fall off
anyway.

--------------------------------------------------------------------------------------

Stealth (working on it and I'm eaa712250 ) Pilot

--------------------------------------------------------------------------------

-R.S.Hoover
-EAA 58400
-(Been there; did that. Got the T-shirt)

wrote in message
oups.com...

Stealth Pilot wrote:
(veeduber wrote
And if that sounds slightly fey, as I'm sure it will to most of the
kit-assemblers, consider the other side of the coin: If the designer
provided you with detailed data, how would you know they were correct
without duplicating his calculations?

my point exactly. I want to verify the calculations.
--------------------------------------------------------------------------------------

Then flip that puppy over and start stacking on the cement sacks.

--------------------------------------------------------------------------------------

the aircraft I am
building is aerobatted by some and declared by others to have a 3.8g
ultimate wing. only access to the designers numbers will allow me to
sort the bs from the advertised claims and see what the actual
situation was when designed and now.

--------------------------------------------------------------------------------------

Well... I hate to tell you this but the numbers alone won't give you
the Ultimate Answer. Load it to the max, turn it inside out whilst
upside down and you're liable to fail some itsy-bitsy part that was
never included in the calculations... but causes the wing to fall off
anyway.

--------------------------------------------------------------------------------------

Stealth (working on it and I'm eaa712250 ) Pilot

--------------------------------------------------------------------------------

-R.S.Hoover
-EAA 58400
-(Been there; did that. Got the T-shirt)

For example, How many negative G's will your battery box take before it
releases the battery to depart the airplane in whatever manner it may
choose?

Highflyer
Highflight Aviation Services
Pinckneyville Airport ( PJY )

Hey, start planning now --- 10th annual Pinckneyville rec.aviation flyin is
coming up May 19, 20, and 21. The motel is filling up fast! :-)

"Highflyer" wrote

For example, How many negative G's will your battery box take before it
releases the battery to depart the airplane in whatever manner it may
choose?

Is there a story in that, HF? Have you bee doing some secret battery box
testing, without telling us about it?

Remember, confession is good for the soul! ;-)
--
Jim in NC

Highflyer wrote:

Hey, start planning now --- 10th annual Pinckneyville rec.aviation flyin is
coming up May 19, 20, and 21. The motel is filling up fast! :-)

Highflyer
Highflight Aviation Services
Pinckneyville Airport ( PJY )

WOW, has it really been ten years? Why it seems like I've personally
known some of you clowns damn near forever.

- John Ousterhout -

Unofficial Pinckneyville Fly-In
http://www.ousterhout.net/pjy-faq.html