Though there are several factors that are important in the design of a Flying wing, the #1 most important thing to get it right is :
Center of Gravity (CG) Flying wings are very touchy with CG.They usually offer very tight acceptable tolerances, and fly very poorly, if the CG is even a few MM outside the recommended position. A great tool to calculate the starting point of the CG is :
http://fwcg.3dzone.dk/This tool takes in the Wingspan/Root Chord/Tip Chord and the sweep and gives a good approximation of where the CG should be.
The airfoil is the other important aspect. Though in my opinion a bit over hyped. On many forums, people have gone at length to state that you need a reflexed airfoil for a flying wing to fly properly. The problem with reflexed airfoils, is that usually they are too thin, specially at the trailing edge, and though it may be possible to make models from balsa accurately, the same is not really possible with foam. Plus with swept wing airplanes you do not need the reflexed airfoils, you can probably do with any airfoil, just a little up Elevator gives the necessary reflex.
I am going to continue my flying wing design thoughts and experiments at my blog :
http://www.vortex-rc.com/2017/11/21/designing-building-epp-flying-wings/and more frequent updates ( photos and videos ) are being posted on my Facebook page :
https://www.facebook.com/VortexRC/Its just very convenient to share media there directly from the phone, than to being it here on the forum.
Just did few test planes :
1. 600MM Micro FPV plane. Designing and Building some EPP Flying Wings
http://www.vortex-rc.com/2017/11/22/600mm-epp-flying-wing/Built this and ended up tail heavy. Had to move the battery too far forward to balance, Gave up and added a blunt edge that protruded ahead of the nose. Dont like that sticking out, so probably will be increasing the sweep to get the CG a bit behind, and also getting the motor a few MM forward, I can use a lighter motor, but prefer to use the quad racer motors which are pretty popular these days. AUW of this plane is coming to less than 200Gms, which is cool.
My next attempt at this would be change the design slightly so as to get the CG without the blunt edge sticking out from the nose.
I did some FPV on this with a the 3-in-1 All in one camera. .Seems to be a fun plane. Very light. Very small , and a good deal of fun.
The EPP material just makes it too cool.
2. Been playing around with the 1200mm size design. Designing this around 3700mah 4S or 5000mah 3S Lipo, fully enclosed/covered battery and electronics bay, with enough space inside to put all the electronics including autopilot ( Pixhawk / inav etc etc ) , Forward Live view FPV cam and HD Cam, and also have space for a downward facing Camera for aerial photomapping.
Check out the intro here :
And the maiden here :
The maiden was super. Had gone in with a light setup. Used a smaller 2200mah 4S lipo, and no autopilot etc.
Next step would be to start adding in the gear and take it up one step at a time.
3. Also a 36 inch FPVWRA FPV Wing Racing Association Spec Flying wing. This is per the standard spec, that meets the FPV Wing racing guidelines.
Flew superbly, did the maiden today, infact went on FPV right after launch on the maiden itself.
Tracked as if on rails, and extremely smooth and very very fast. Just loved it.
EPP material makes it very strong and light, and i would say this is one of the most fun and exciting FPV plane i have flown. Very fast, very smooth, and just brilliant..
I have several gigabytes of videos and pictures, trying to sort them all out so i can organise and post them here.
Really Really eager to bring out share these planes with all of you guys.
Before i can offer the kits on my website, there are certain things that i need to do :
1. Stock up on the CF spars.. Need the strips for the reinforcement
2. Find out on a good source for Balsa aileron stock . I am using the EPP ailerons/elevons now, but want to offer Balsa elevons as an upgrade. From what i have searched around i haven't found a good supplier yet. Maybe someone can help me here.
Lots of things still to do. But very excited !
Will update here as we move on with this project.
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