Have you guys ever noticed the void?

I look at all the plans on offer for building aircraft and not one of
them ever includes any of the structural calculations.

Dont you guys ever feel totally unnerved by the fact that you have no
real idea of just where the strengths and weaknesses lie in a design?

If you cock up something during construction and you need to work out
whether it will be strong enough to carry the loads in spite of the
mistake how on earth do you make a sensible informed decision?

I never fail to be amazed that the absence of key information
verifying the structural integrity of a design is never seen as a
problem.
methinks it would make a really good EAA initiative for the second
century of aviation to start educating people to make available their
structural calcs.

Stealth(its a world wide void) Pilot

Stealth Pilot wrote:

Dont you guys ever feel totally unnerved by the fact that you have no
real idea of just where the strengths and weaknesses lie in a design?

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

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.)

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.

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? 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.'

Expecting the EAA to do something about your 'void' is wishful
thinking, in my opinion. Based on the advertisements and informercials
in their magazines, the EAA has no qualms about accepting money from
hucksters offering you everything from flying saucers to engines that
will rust out before they wear out.

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 :-)

-R.S.Hoover

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. Most every calculation I need to make comes from an average, if
not a guess.

I don't see this as much of a problem. Most builders wouldn't know
what they were looking at anyway. Some of them can't even drill a
round hole in the right spot :-)

If the manufacturer has preformed static load tests, with
documentation, and the design has been in service for a while I
wouldn't have any worries. I wouldn't buy/build one that didn't have
documented load tests available, or many years of proven service.

If you cock up something during building replace it. If you have the
ability to properly calculate and test the repair/modification you
shouldn't need the original calculations.

As for the EAA initiative I would be in favor of some kind of a formal
independent plans rating system. The old NASAD was one such group. It
could keep lots of people from wasting money on plans for things like
the FX ultralight and jet powered rotor cycles.

I do have the designers calculations for my Duster, but if/when I do
modify it I'll do my own calcualtions from scratch.
======================
Just my opinion
Leon McAtee

I did some basic calculations on the wing used on the Chuckbird/Texas
Parasol
before building my first one. I came up with a shade over 4 G's at 650
pounds.
(seemed like a good idea before selling plans)

Then got Nuked by several guys who claimed the wing was "weak" - because
they
were building 650 pounds - EMPTY.(and it was my fault!?!)

E-bleepin'-nough!

Richard

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. Most every calculation I need to make comes from an average, if
not a guess.

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

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


especially when they then use the SAME name for the aircraft...

John

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.

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

Matt

Matt Whiting wrote:

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.

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

Matt

Bless you pilgrim, for you are wise beyond your years.

The designer may hate it when you change a few things, but as many
people have pointed out, every pilot is different. Some changes are a
need and some are for want. Is this any different then a person
customizing a harley to their liking and calling it a Harley? There are
many reasons to change somethings on a design, espessially in this
catagory.
Lou