This is my new build, a 1200mm flying wing... I take the liberty of sharing my thought which went into the design of the aircraft. Please feel free to comment, would love to have a discussion and learn more.
This design explores the region between a plank and a swept wing flying wing, and to try and get the best of both worlds (to whatever extent possible. It is all about choices).
-A span of 1200mm was chosen to keep it a one-piece plane (hanger space and transporting ease).
-Sweep is a very moderate 13 degrees at LE, and even lesser when measured at 1/4 AC line across the span. (less twist at wing tips. and larger efficient flight envelope)
-Aspect ratio - 6.3 .. (adequate wing loading for the set span)
-Taper ratio - 0.65 and Twist - (-)1 degree. (close to elliptical lift distribution, less drag, while maintaining decent Re and flow characteristics at the tips, good stall characteristics).
-Airfoil is PW51.. (decent cl/cd, appropriate cm, and minimum trim losses).
-A central tailfin over wing tip fins ( due the the small moment arm and the issues arising out of a bad wing tip. Chances of which are high).
-Fuselage was kept to the minimum..(to reduce drag).
-A sharply raked symmetrical wingtips to pull the tip vortices outwards and have separation between the tip and elevon outer edge.
---The design and parameters was tested and fine tuned over a couple of iterations on XFLR 5.
Construction is foam, fibreglass, carbon fibre composite and some custom designed 3D printed parts. It is a 4S setup and has a F60 Tmotor(yes quad motor).
Maiden flight done.... Climbs at 30% power and it is FAST and has a amazing glide. Very good energy retention... Overall Flies exceptionally well, quite similar to a Swift/Fox powered glider.. (The only change post the maiden flight was to add some downthrust).
Here are some flight pictures . I will share a video shortly . For more details, please visit myrahulroy.blogspot.com
Happy Flying
Rahul
IMG_3563.jpg
@Rahulroy31
Amazing work!
All that remains is to compare performance with a version having a horizontal stab and no reflex!
I have no idea why PW51 suits planks/tailless.
Barely has a hint of reflex.
Are the elevons providing the reflex?
Regards
Iyer
yes, it hardly has any apparent reflex, it manages to move the TE airflow upward (relatively) by having a clean and slightly upswept lower surface and without pressure hotspots.....PW51 balances camber (read cl) and reflex beautifully .. .. other reflexed airfoils have higher camber /lift (cl), more cm, and hence need more reflex, but they also have higher drag. ..what PW51 looses in coefficient of lift is compensated in the total overall lift by speed (v2)... so for slow speed you have to trim it with more reflex but can start reducing the uptrim input as the speed increase. ... mine is just @ 2degree uptrim at launch.. and immediately starts to climb as the speed builds up.
on a tailed aspect ..
Over the whole flight envelope, a tailed glider PROPERLY trimmed would be more efficient .. in planks, you need to dial in the CG precisely, and after that they are auto stable and trimmed. .. and FOR ME building a fuselage is a pain 8-) , added effort /time and weight, (also lower over Oswald #). Hence it has been WINGS for me ;D
It looks excellent, could you please share the electronics used ESC, SERVO, RX and also the Lipo, and what is the AUW ?
motor is F60 Tmotor 1750kv (yes a quad motor). 40A Tmotor ESC, 2x 9pm Emax servos and 4S 1500mah bty
A very clean and elegant design , it is.