Load testing for unknown wing.

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Lendo

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User 27, weight is MTOW * G load selected, less wing weight. How to load the wing elliptically is the secret. Not all wing are perfectly elliptical but close enough for the load test. Once seen the whole process is pretty simple. Can't understand what all the nervousness is about. Basically how to spread the load, as Billski suggested the weights that should be considered for that load, and he's an engineer.
George
 

Lendo

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BoKu, I think I know what he might be alluding to, the possibility of Litigation following advice, if it ended in Tragedy. Every bit of advice on HBA, needs to be considered as "at users rick".
There are other things to be considered when considering weight Loading and they are the load the Horizon Tail load exerts on the wing and where the loads need to start and stop, where the weights need to be placed etc. However as long as the weight is distributed Elliptically and totals the weight calculated and the Wing doesn't fail in the process - all should be good.
George
 

proppastie

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distributed Elliptically
the most accurate but there are the other schemes that are sightly more conservative and can be used,.....however 10% conservative at approximately 10000 pounds is another 1000 pounds.
 

Lendo

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proppostie, I'm a bit of a stickler for accuracy (as rounding numbers up or down is for experts), that's why I developed my own approach is somewhat labor intensive, it's as accurate as anything can be in Aviation calculations, but I also like to compare methods. I did a comparison on LIft per AOA from 3 different sources, one from Eminent expert from England one from John Roncz and on from the Emery Riddle Book (GAAD). They were all different and took the sweep angle from three different locations, one the Leading Edge, one from 25% and the third from max thickness - all were within 1% of each other. From this I knew I had accuracy. My fourth (original) method was much easier but much less accurate :).
George
 

Lendo

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I think I will write this up in Word, for those who may be interested, with the proviso 'use it at your own risk'.
To show the difference at 15% my answer was 48.41832095° JC's was 48.42°, one might suspect simple rounding-up - I did initially.
However at the tip my answer was 25.01533069° and JC's was 23.85° - that's over 1° difference.
George
 

Lendo

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Oops, put this up in the wrong site, it should have been to do with Propellers.
George
 

Tantrum1

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Take a look in my members build log "Snoshoo SR-1", you will see how I load tested my wing. Full disclosure my wing isn't an akro wing, but the principles remain the same. Its really not that hard, you are probably very much like me and are over thinking it. If you have a schematic or blue print of the wing internals with dimensions, then most aero engineers could provide you with a load schedule pretty quickly. Mine was basically divided into 5 bays with the center of each bay being over a rib. I gave the Aero Engineers (2 different ones) the specs on my weight bags along with the MTOW of completed aircraft and the weight of the wing, and they gave me a load schedule.
 

Lendo

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With My method you don't need an Engineer to develop a Load Schedule, why pay someone else when you can easily do the same job yourself and gain some knowledge and and understanding along with the process.
Everything is easy when you know how.
George
 

Tantrum1

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With My method you don't need an Engineer to develop a Load Schedule, why pay someone else when you can easily do the same job yourself and gain some knowledge and and understanding along with the process.
Everything is easy when you know how.
George
I don't disagree with you there about learning the information. However it was likely a one time event and I have alot more on my plate then to learn the math/process. I may go back and learn it as it is interesting but after my aircraft is built and flying. That being said it was a fast and easy decision to have 2 aero guys do it for me, one of the engineers was/is part of the design holder, and the other was a friend. I was lucky enough that it did't cost me any more then a couple of beers, of which i was going to drink regardless. LOL
 

Lendo

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Fair-Enough Tantrum, just trying to encourage 'learning the process', and improving safety through testing. I will be writing it up anyhow, but stuck finding some of my notes at the moment - now where did I put that information :)
George
 
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