Scratch Build Glider Protoytpe

by AG Pro | January 23, 2014 | (0) Posted in Projects

Angel Gendut Productions presents:

Scratch build Glider prototype for soaring mission. Increased wingspan to 1.4m with 8°-10º dihedral KFm2 wing. Control surfaces : 2 Flaperons, 1 Elevators and 1 Rudder.

Design review :  - Front fuselage is too short for proper COG adjustment

                        - Ailerons are required at the end of wing tips

                        - Main wing surface area is too small for effective lift force

 

 

 

- Find this article & others like it at www.FliteTest.com -

COMMENTS

alibopo on February 18, 2014
Hi - it would be much easier to comment on the flight characteristics if you ran the footage in real time. However, it looks like a good enough design - constant pull to the right - counteract with opposite rudder or a few 'trim-blips' on the ailerons? You do appear to have ailerons, which look big enough to be effective even close-in to the fuselage so I wouldn't go for any major changes there just yet. Yes, you do seem to have very little fuselage projecting forward, so you've probably loaded the front with a lot of weight to get a reasonable starting CG - that can't help with the wing loading. However if you fly faster you'll get more lift, so wing loading shouldn't be that critical. I'd just stretch the nose, allowing you to reduce the overall weight, then get a bit more thrust by increasing the prop size/pitch and drive it faster. Looking forward to the next outing :)
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AG Pro on February 20, 2014
Hi alibopo. Thanks for the comment and sharing your thoughts on the design. Notes taken; I will include the real time footage on my future videos. I am still learning about video productions; especially on the optimal output settings. I believe the most critical problem is caused by the improper CG location; this should be causing the ailerons to function ineffectively while it is tail-heavy? However, I am still developing this glider design and I will share the experience. I am currently developing a website by which I can share the design plans for most of my aircraft.
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alibopo on February 21, 2014
Hi AG Pro, OK the video is pretty good :) but it didn't show me what I wanted to see - you can't please everyone. Anyway - regarding the plane, the CG didn't look too bad in any of the flights. Then comparing the cut-down wing flight to the previous very short flights it was looking a LOT better - maybe one of those dihedral wingtip panels was twisted out of true and creating that constant right turn? Another thought - though it was hard to tell - your prop and motor seem small for this size of plane. Maybe you didn't have enough thrust when the wings were longer - some of those high-pitch props need to get up to speed before they start working efficiently - with less weight and less resistance the plane seemed to fly a lot better. I don't know the KV of your motor but it looks like you could get a longer prop in there. A bigger prop with less pitch would give you more thrust at lower speeds. Finally, I'm thinking you must be able to counteract that right turn tendency with a combination of left rudder and left aileron. A lot of 'real' single engine prop planes fly with a few degrees of constant left aileron to counteract the motor/prop torque. I think you just need to trim it out. Looking forward to the next flights. Cheers.
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AG Pro on February 21, 2014
I missed the crucial information; the aircraft's spec. My bad. For this aircraft, I use Turnigy 2836 / 1000kv for the motor and 8 x 4.5 SF for the Slow fly electric propeller. the motor run from 50A ESC from hobbyking. The AUW is estimated at (790-900) grams. Yes, the dihedral wings seems to bend too much in the video, the extension dihedral wings have no carbon spar in them, but the main straight wing I have it installed. I prefer a pusher type aircraft because it prevents the motor from nose-dive crash; especially the maiden flight :) . However, this pusher configuration does not allow large diameter prop, unless I redesign the aircraft's motor mount height. I do have another design, a sport trainer which have been flown successfully. You may check it out on my articles, protoyping UAV/FPV DLE-TR01-00. Once again, I greatly appreciate your thoughts and support. Cheers mate!
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alibopo on February 21, 2014
Hi again - that motor should have plenty of power for this model! :) But, based on my experience, the prop is just too small to make use of all that power. A higher revving motor would do the job(1500KV), or lift the motor mount and get a 9 or 10 inch prop on it (remembering to include more upward tilt to direct the thrust towards the plane's true CG.) Look near the end of my article; http://www.flitetest.com/articles/find-your-centre-of-gravity, for info on adjusting thrust angles. It really makes a big difference getting this right for a pusher plane.
I had a look at your other pusher - that flies very nicely. Cheers.
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AG Pro on February 23, 2014
Yes, I have read your article when it was published. It was remarkable :)
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Joni_DLE

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Scratch Build Glider Protoytpe