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-   -   Looking for tips: unwarping a glider body (http://www.oldrocketforum.com/showthread.php?t=17638)

aeppel_cpm 12-22-2018 02:27 PM

Do you fly at Bong? It will likely fly there.

aeppel_cpm 01-29-2019 08:18 AM

Some update pictures. I will countersink and cover the nose weights eventually.




Ez2cDave 01-29-2019 10:40 AM

Looking good . . . When is the first test flight going to happen ?

Dave F.

aeppel_cpm 04-08-2019 08:03 PM

I guess I built too heavy. I can't get her to glide in hand-toss testing. She just flops. Doesn't seem to be unbalanced - just doesn't fly.

Ez2cDave 04-08-2019 10:38 PM

Quote:
Originally Posted by aeppel_cpm
I guess I built too heavy. I can't get her to glide in hand-toss testing. She just flops. Doesn't seem to be unbalanced - just doesn't fly.


Can you shoot some video of what's going on ?

It could be diving, stalling, or "mushing" . . . There might be a wing loading problem ( too heavy) or an "incidence" ( alignment ) problem involved.

Dave F.

aeppel_cpm 04-09-2019 11:30 AM

I'll think about it Dave, maybe I won't give up just yet. I went looking for my wing loading notes, but I can't find them. I'll re-estimate and re-weight and post. Because it may be too heavy to be worth the effort. I thought I was ending up in Estes Sweet V territory, but I might have miscalculated.

I think it's neither diving, nor stalling. (Had to think about the grammar I wanted for a second.) It looks like it has a left yaw that I wasn't able to trim out. Could be that blasted warp. And a left roll. I'll have to revisit the left-right balance (I was focused on the Cg previously) or maybe use clay (eek, more weight) if there is a dLift/dY. And, now that I've looked it up, I think 'mushing' is a good description of what it was doing.

Ez2cDave 04-09-2019 11:58 AM

Charles,

Here is more about "mushing" . . .

https://aviation.stackexchange.com/...a-mushing-glide

Dave F.

aeppel_cpm 04-09-2019 12:02 PM

Yes, I found that article, too.

jetlag 04-09-2019 02:53 PM

Charles,
I balance all my airplanes a bit nose heavy; slight nose heavy is your friend!
R/C, glider, sailplane, boost glider all get the following treatment:

I find the recommended cg location and screw in a small screw eye dead center (left-right) at that point. Then, I hang the model from a string. This way, one can see left/right as well as front/rear balance in one easy step. Adjust counterbalance as needed.
Never fails.
With the warpage, you may then need to build in some aileron influence. Sometimes, a stiff piece of tape to one wing to make an aileron is all that's needed. Just trim the tape to get desired effect/influence.
I suspect your glider to be tail heavy, too. I'd bet a $1 on it!
Do the balance first, then see how she does. You might be pleasantly surprised!

Pretty glider! Looks like a great finish!
Allen

ghrocketman 04-09-2019 04:26 PM

+1 for placing a bet on "tail heavy".
Roll can be balance or warp related.
Yaw is usually caused by fin/rudder misalignment, but could be due to an extreme tail heavy condition or not enough rudder/fin area.


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