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May 24, 2019, 06:33 PM
Aurora Builder
Interesting. Any idea what they change in the layup?

It’s certainly a bummer but seems pretty easily rectified...
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May 24, 2019, 09:28 PM
I'm not as bad as they say.
Quote:
Originally Posted by samc99us
Interesting. Any idea what they change in the layup?

Itís certainly a bummer but seems pretty easily rectified...
My understanding is that the weave on these fabrics is not always completely symmetric, thus you have to fiddle with the cut pattern to get the slightly stronger directions aligned top and bottom.
I wish I could remember where I was reading this factoid. I bet Siler knows or can debunk what I got second hand.
Latest blog entry: AIrcraft I've built.
May 25, 2019, 02:57 AM
Registered User
Quote:
Originally Posted by mnowell129

You can fix them with heat and the right touch, so it's seldom an end of the world situation.
Way better than the old days with film covered wings, that's for sure.
Haha takes me right back to the days of cellulose dope and tissue ..!

Anyway can’t wait for this to arrive, everything is here just waiting for the airframe.
Last edited by DizzyDuck; May 25, 2019 at 03:28 AM.
May 25, 2019, 11:20 AM
Aurora Builder
Quote:
Originally Posted by mnowell129
My understanding is that the weave on these fabrics is not always completely symmetric, thus you have to fiddle with the cut pattern to get the slightly stronger directions aligned top and bottom.
I wish I could remember where I was reading this factoid. I bet Siler knows or can debunk what I got second hand.
That is kind of what I was thinking. A much lower probability than with the unbalanced glass fabrics but often the weave isnít dead nuts symmetric when overlayed top to bottom. Prefacing technique is probably another factor, as is time in the mold curing. Iím asking as I hope my molds arenít warped but anything is possible. I would think that the Falcon team has quality tooling as well and I would be surprised if we both have warp issues in said tooling, but fabric choices are similar among DLG builders so that is a more likely concern. I think Kristoff switched to Textreme in the ailerons to help with this issue.

All in all it sounds like a minor issue with an otherwise great looking ship and a really neat design target!
May 26, 2019, 01:28 PM
Registered User
Quote:
Originally Posted by mnowell129
.... you have to fiddle with the cut pattern to get the slightly stronger directions aligned top and bottom. ....
So, does this mean the curing process produces strain in the structure? From shrinkage or something? At first read, I thought this meant the wing would flex/twist unevenly under (launch) load.

Woody
Last edited by Tower_City_Woody; May 26, 2019 at 03:09 PM.
May 26, 2019, 06:36 PM
DLG Addict
Scrib's Avatar
Had a great day out with the Falcon today. I hosted a little practice at my club field in central NC. Was a lovely day for flying except for the heat (temps were somewhere between 95F and molten rock).

It really held its own against a tough crowd of CX5s.

The wind picked up to a pretty stiff breeze in some long cycles. I was a bit worried that I didn't have ballast made up yet. Turns out the Falcon can operate over a pretty wide range of conditions at a standard layup weight of 217g. I was very pleased to be able to follow lift downwind and make the field with ease, penetration is excellent.

Loving it.

Jason
May 26, 2019, 07:50 PM
I'm not as bad as they say.
I stared at it a few minutes and asked myself "Why not just make solid 1mm pushrods?"
Couldn't think of a reason not to.
Centering is perfect with the lack of stiction....
Latest blog entry: AIrcraft I've built.
May 27, 2019, 06:55 AM
Oleg Golovidov
olgol's Avatar
Thread OP
@ Mickey - Nicely done, thanks for posting. I knew you would go with solid pushrods This is certainly a good potion for those who have the right materials.

@ Jason - I wish I could join you all for the practice. On a family vacation at the moment.
May 27, 2019, 07:15 AM
DLG Addict
Scrib's Avatar
Mickey, looks good. The horn bearings are cool too.

To be fair, I don't seem to have a double centering issue with the supplied equipment. The movement is smooth and the servos are ridiculously strong. Maybe with the inevitable increase in gear slop there will be more opportunity for problems with my setup.

Jason
May 27, 2019, 10:33 AM
I'm not as bad as they say.
Quote:
Originally Posted by Scrib
Mickey, looks good. The horn bearings are cool too.

To be fair, I don't seem to have a double centering issue with the supplied equipment. The movement is smooth and the servos are ridiculously strong. Maybe with the inevitable increase in gear slop there will be more opportunity for problems with my setup.

Jason
Yep. I'm not saying that the stock setup is bad. It just looked like a perfect setup for solid pushrods.
Frankly what pushed me over the top is that the hole in the MKS servo arms is 1mm, so I was faced with drilling a .8 mm hole somewhere in the one horn they gave me, or just using the 1mm hole. Then methinks, hey just drill out the aileron horns to 1mm, then it starts to make sense to just glue the carbon tubes to solid wire.... And I'm off on an adventure.
Latest blog entry: AIrcraft I've built.
May 27, 2019, 10:37 AM
DLG Addict
Scrib's Avatar
And that's what makes you an engineer and me an English major. I didn't think to measure/align that stuff. haha. Nice work.

Jason
May 28, 2019, 11:49 AM
I'm not as bad as they say.
Off topic
Last edited by mnowell129; May 28, 2019 at 03:29 PM.
May 28, 2019, 12:19 PM
Oleg Golovidov
olgol's Avatar
Thread OP
For my customers that received a Falcon recently: if you see a twist in the ailerons, let me know via private email [email protected]

I have communicated with the factory about this and they promised to
(1.) fix the issue on all future wings by paying attention to the fabric orientation, and
(2.) replace all warped wings.
May 28, 2019, 01:03 PM
I'm not as bad as they say.
Off topic
Last edited by mnowell129; May 28, 2019 at 03:28 PM.
May 28, 2019, 02:14 PM
Father of Fr3aK, DLG Pilot
tom43004's Avatar
Thinner wings have more of a tendency to warp than thicker ones. I had issues with the first few NXT wings I produced. My issues weren't lack of fabric mirroring as much as an asymmetric doubler I was using in production. It was a doubler that was under the hingeline used for stiffening the aileron / facing. About 1/4 of the first batch of wings eventually warped a little. I still fly one of them occasionally that I got back when I replaced a customer wing.

It takes very precious little warp in a DLG wing to be noticeable. Oleg sounds like he has the issue handled, if there's a systematic issue at all.

Asymmetric layups can be used without warping, but you have to pay very particular attention to resin content and leave the parts in the molds for much longer. It's easier to be consistent with lower resin content than with higher. That was how I fixed early NXT warping. Later I just made the doubler the same top and bottom so I didn't have twisting opportunity.


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