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James Grahn
 Post subject: Re: Aileron weight.
PostPosted: Mon Dec 10, 2018 5:35 pm 
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Those are questions with no answers. An aeroelesticity engineer would have to study the specific changes. I’m not one of those. I can tell you this.. the ailerons are not 100% balanced. You can prove this to yourself by disconnecting the push/pull from the mast. The Aileron will hang down even with the balance attached. I was told by Lyle Trusty that they somewhat rely on each other for balance. I’m not sure what that means. However, since they are about 2/3 balanced, any changes to the weight of the Aileron itself will take you into uncharted territory. What/where will the effect show up? That’s anybody’s guess.
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bloke727
 Post subject: Re: Aileron weight.
PostPosted: Mon Dec 10, 2018 8:10 pm 
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All understood (I'm an Aeronautical Engineer - at one time I could spell aeroelasticity), I'm just wondering what the 'starting point' is. Is the counterweight a standard item or is it based on the weight of each aileron? When I tested fighters in the Air Force I had an ejection seat. Now at least I can release the canopy and dive out after the wing flutters off........

The ailerons on my "Mini A-37" have a weight of 6 - 8 oz at the trailing edge when I disconnect the pushrod. It would be nice to know if that is reasonable before I expand the envelope - or test the parachute!

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dondday
 Post subject: Re: Aileron weight.
PostPosted: Mon Dec 10, 2018 9:26 pm 
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What ever came of the balance weight molds Dean Cochran from Colorado had?

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jrevens
 Post subject: Re: Aileron weight.
PostPosted: Tue Dec 11, 2018 12:15 am 
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dondday wrote:
What ever came of the balance weight molds Dean Cochran from Colorado had?


I believe they were loaned out to someone and never returned ... I looked for them when Dean passed away. If Tony (Dean's son) reads this, maybe he can confirm for sure whether they are still with him or not. Next time I see him I'll try to ask.

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James Grahn
 Post subject: Re: Aileron weight.
PostPosted: Tue Dec 11, 2018 10:55 am 
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I have molds for the ailerons.
The weights are a standard item. They are fabricated IAW plans. If the builder manufacturers the Aileron IAW Plans, it should be fine.
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bloke727
 Post subject: Re: Aileron weight.
PostPosted: Tue Dec 11, 2018 8:19 pm 
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So that's the question, several people are talking about modifying the aileron with things like trim tabs. If the weight is a "standard" size we should come up with a "standard" balance. That way the weight can be modified to account for any change in aileron CG. The T-18 doesn't have a history of flutter problems and we don't want to start any. The other crowd (starting with a V) have lost a couple due to flutter. It's a sneaky beast that doesn't give any warning and doesn't often give you a second chance.


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James Grahn
 Post subject: Re: Aileron weight.
PostPosted: Wed Dec 12, 2018 1:17 am 
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All true. I don’t know enough to comment. My race project has an Aileron trim tab that was designed by Lyle Trusty. I used his plans. Anything other than that, you are on your own.
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Jeff J
 Post subject: Re: Aileron weight.
PostPosted: Wed Dec 12, 2018 7:07 am 
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I accidentally took off with my canopy unlatched one time. Good luck opening it in flight.

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bloke727
 Post subject: Re: Aileron weight.
PostPosted: Wed Dec 12, 2018 10:48 am 
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I have pull pins on the canopy rollers with cloth handles snapped to the frame. I'll give a full report if I ever have to eject.
As for the aileron weighs, I strongly caution against making ANY modification to flight controls, especially anything that changes the weight of the control surface, unless you can perform a proper weight and balance and do the appropriate flight test analysis.
Is there any guidance in the construction about control balancing?


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James Grahn
 Post subject: Re: Aileron weight.
PostPosted: Wed Dec 12, 2018 11:35 am 
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Sounds like you do not have plans. I would strongly suggest you get some.
Bottom line is that the plans show desired max control deflection. They also show allowable balance weight. Beyond that, no.
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