Composite Wing Builders Lounge.

[edwinzea]

Dear Jim

nice that you started this thread. I had been fiddling with this idea for some time, but I was busy building the DLG planes for this season

West systems (slow) works really great for me, I was using carboline on my last built and it was a blast, check it on hyperflight of vladimir models. THis fabric is the future. But having build some DLGs on the past few years I think a glass over XPS should be enough.

And yes to T blades, it helps you transferring the force into the plane much better, and the arm is in a more confortable position during and after launch

EZ 8-D

[dylan1024]

Hi Jim

I am looking at machining molds for composite wings, I used the coordinates for StanfoilBEmod2 but get some slightly odd results:

the flat on the leading edge is slightly concave and towards the TE the foil reflexes slightly then pulls in to the final TE thickness.

do you have any other info on this foil? LE radius? should it be a razor sharp LE?

Kind regards

Dylan Roberts

[Richard Ewing]

Dylan,
You might check to see if the CAD software you are using has an option for smoothing that can be turned on or off.  I know I got some interesting results with one of the BE airfoils that had the flat facet near the leading edge when I had the smoothing function on.  Switching it off made the shape look much better, (the upper surface behind the LE radius changed from concave, to flat). 
Rick

[dephela]

I've used blades but gave them up for what I thought was a better launch just gripping the wing. Can someone post a pic of the T blades being used now?

Dennis

[sweepettelee]

Dennis,
Go to post 25 from Dec 13. Click link to T- Grip.

[dephela]

Thanks Lee. I have two f/f dlg's without blades and one with. I think I still like without the blade. Next time I go out it will be with a glove and I will have tried all the ways!

[jim_buxton]

Dylan, sorry I kinda drifted off of this thread for awhile.  Did the advice you were given solve the problem?  The wing should look as the image shown.
Regarding throwing blades/pegs/gloves style...it is 100% user preference.  There is no right or wrong.  If you like it, it is right. 

I prefer no peg on smaller lighter models.  I can accelerate these with my wrist at the moment of launch with a flick of the wrist and get better launch height than I do with a peg.  The models I fly this way are my indoor models.  40-50 grams, 33 inch span or so. 

I absolutely need a peg on my 39" composite models that weigh around 120 grams.  I tried one without, then added a peg and tried again.  I picked up 20 seconds in dead air with the peg. 

Look at the 1.5 meter 9 ounce DLG's, every last one has a peg, and guys are throwing them 300'.

The standard outdoor sized FF glider at 36" and 80-90 grams is right in the transitional area where it might be better for some to use a peg, and better for others not to.  I strongly recommend you try it both ways and do some testing to determine what works best for you if you are in that range.
~Jim 

[dylan1024]

Hi Jim

yea, we came right with the foil. we re-drew it from bits of info and your co-ordinates. set of wing molds to follow soon

[dylan1024]

510mm span for each half. StanBEmod2 foil... or as close as we could get. Bottom surface mold is on the machine

[dylan1024]

Rohacell 31 cores and Vlad 29g carbon. 57.8g

[dylan1024]

Blake just popped second wing out the molds. This one is much lighter.

[jim_buxton]

These are GORGEOUS!!!!  Since you have molds you must make more to recover some of the cost, correct?!?!
~Jim

[F3KBlake]

Ok so who is going to design us a new airfoil for bagged and moulded wings? Or is StanBE Mod2 good enough?

[Rewinged]

I think the answer might be somewhere between StanBE Mod2 and recent LD F1A airfoils.  Compare the RE of F1A and your glider; maybe that will be informative.  Also look at the airfoil Ken Bauer has been using for FF CLG and HLG.  Sort of in between.

Just guessing.  Tmat said that their studies couldn't find anything notably better than StanBE Mod2.

--Bill

[dylan1024]

Would a flapped foil be worth looking at? Something similar to indoor where they rely on it flattening out for high speed launch and the camber pulling back in as it transitions to glide?

[dephela]

I've used Mark Drela's AG04 on my balsa winged planes and they seem to perform well. I have some cores cut, still mumbling to myself about bagging them.

[Tmat]

Lovely work. How do you handle the leading edge. What's the materials and process?

Tmat

[F3KBlake]

When moulding the TernFree wing we just simply use a small bead of splooge top and bottom LE to join the skins together. The trick is the type of splooge. We use a product from Axxon called 9940. Its extremely tough semi rigid epoxy. Any splooge will do, except i found most epoxys cure hard and brittle rendering the LE hard and brittle. 9940 can take a lot more abuse before it splits. Chances are that if there is one fence post on the field your model will find it. Its nice to walk away from those moments and carry on flying.

Blake

[-John-]

Ok so who is going to design us a new airfoil for bagged and moulded wings? Or is StanBE Mod2 good enough?

One could always acquire the Profili software and do some runs(or mods) of selected airfoils to find out what might work well.
...I think the quest for the ultimate airfoil(s) has occurred since the beginning of flight.