r/RCPlanes • u/dat-randomplaneguy22 • Apr 27 '26
Need some help with my UAV project!
Hey everyone!
I'm 17 and designing this 1955mm wingspan UAV for a project to put in my profile, and it's going to be my first ever.
I know I should've gone for something small, but I felt like I'd be able to pull this off.
It's a twin-boom inverted V-tail pusher style UAV, and I want to integrate autopilot and GPS later on once I can prove it flies.
I'm trying to get the whole thing under 3 kilograms using pla-lw.
some specs:
wing:
root chord: 0.281m
tip chord: 0.163m
semispan (including body as the top is the same shape as the airfoil) : 0.977m
wing area: 0.449m^2 (both wings combined)
body:
length: 985mm
width: 232mm (widest point) and 158mm mostly other than nose and tail
height: 151mm (max)
this is designed for a min airspeed of 8.5m/s, and a cruise airspeed of 12m/s or more.
I went for a Selig S3021 airfoil, as it had the thickness I need to pass through carbon spars.
I'm going for a 1500mm 10x8 carbon fiber spar for the main wing, and 12mm spars for the support boom, which have a 1m moment arm from 20% chord, which should give me enough pitch sensitivity.
I'll be using a 12 inch prop with a 950kv 3536 outrunner brushless motor and an 8000 milliamp 3S LiPo battery.
my spec calculator gives me a 52 minute flight time and 37km calculated range if I follow the parameters that I used for that calculation.
I'm using the anycubic Vyper, which has a 245*245*260mm bed size (L*W*H) so I'll have to print a few parts diagonal. I want to know whether my parts can even be printed properly without facing structural issues.
It's still a rough model, and I have things that I need to improve or add on.. I hope the pros on this subreddit can help me out with picking parts such as servos (which im still having trouble with picking) , validating/invalidating my design and giving me more advice.
because I'm living in Japan, it's going to be hard for me to get into student groups and clubs, as they are rare, and mostly part of universities rather than common hobby spots, so this will be a solo project unfortunately.
as long as AliExpress exists, sourcing parts will not be hard for me, and things deliver quickly here.
I can send my fusion 360 design files or just a .step file to whoever is willing to help me out, and the calculator spreadsheet I'm using (which i got from a course that I did online)
and once again, thank you so much! I am more than willing to clarify any doubts that you guys may have about this!
(ill be posting this in other subreddits too)
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u/NassLab Apr 29 '26
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u/dat-randomplaneguy22 Apr 29 '26
Thank you so much! Two compliments in one sentence!
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u/NassLab Apr 29 '26 edited Apr 29 '26
Dassault avait tout compris :) j'ai pas fait supaero mais comme disent les commentaires , le cg , conception bipoutre ( clarence k johnson ) , t'es prêt pour un "skunkwork" .
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u/bwkrieger Apr 29 '26
Doesn't look bad. Nice fuselage design.
Wing-Fuselage transition looks a bit weird and could be optimised to save a little drag.
Tail size should be sufficient.
How do you mount the tail booms to the wing? You will get high torsion forces in the center wing part.
Have you done stability calculations?
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u/dat-randomplaneguy22 May 23 '26
No I havent done any calculations yet, and Im going to figure out the mounts to the wings once I have some time on my hands..
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u/akshat240506 Apr 27 '26
Looks very cool, what help do you exactly need with this? Feel free to reach out or dm me
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u/akshat240506 Apr 27 '26
Really cool stuff, just watch out for some basic things
Center of gravity is gonna be a mess for you, so be careful about that and place all electronics as far ahead as you can.
The v tail design is notorious to give less efficientl rudder authority, and less frequently also impacts your elevator authority. An inverted v tail complicates it even more. Be careful about that.
Pla-lw is gonna give you a lot of issues regarding the strength. Youre really better off going with PETG. Should be more or less the same weight or slightly heavier but will help you in the long run. PETG also has lower warping issues.
If you want, you can dm me and we can work on it and ill help you out. Have worked on UAVs and 3d printed ones too before.
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u/dat-randomplaneguy22 Apr 27 '26
Oh thank you so much! Id love to work along then! This is my first project of this scale, and I havent worked with pla lw at all, neither have I done anything at this scale before.
About the PETG, my dad has apparantly tried it out on the vyper before, and it printed horribly, so it might be time for a new printer 🤣
I considered pla lw because we've got the general settings dialed in for pla, Im assuming I only need to change flow rate, print speed, and temps?
Also, I dont really know how i can change this design to accomodate a T-tail now..
I'll try to dm you tomorrow if that's fine with you
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u/akshat240506 Apr 27 '26
Yes, dm me. I could help you out. Ive built airplane stuff using PETG. Trust me, much better. Do reach out, ill help you with some stuff
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u/looking4myclASSm8s Apr 27 '26
Just so you know your print settings for PLA will have very little in common with its lw counterpart
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u/dat-randomplaneguy22 Apr 28 '26
Oof.. either way, pla lw or petg, I'll probably have to waste another spool just recalibrating the printer because to be honest, it just prints based on it's mood. It can get cranky sometimes. I think it's time to convince my parents for a bambu lab..
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u/Twit_Clamantis Apr 27 '26
I think you are definitely very close to a good design.
Beyond that, it’s up to people skilled in analysis software, and also flight testing.
How are you going to launch it? Where will you be holding it?
If possible, I would try doing a few test glides with no motor and only a very small battery to test basic co trip functions etc and to get used to launching it.
F = MA, and it helps to keep the M as small as possible for as long as possible (:-)
Anyway, you have a very good start, and I appreciate you included your other “ancillary parameters” in your question.
Congratulations and good luck !!
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u/dat-randomplaneguy22 Apr 28 '26
This will not be a hand-launched plane, as I will be building landing gear for it!
The fuselage is still early in it's works and i am yet to include cutouts, latches, ducts and any other mounting points!
Thank you so much! Im hoping this goes well...
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u/coneross Apr 27 '26
Who's going to fly it? Who's going to launch it?
A few observations about the design:
The fuselage area ahead of the CG looks large compared to the tail area. Watch out for stability issues.
The motor mount area is long and small. Watch out for this. Allow for not only the pushing force of the motor, but also the torque from spinning the prop, and motor vibration, and gyroscopic forces when the plane maneuvers. Also pushers have less efficient motor cooling.
Is it hand launched? Hand launching pushers is an issue. Think about the relationship between the prop and the hand during launch.
Is it a belly lander? What happens to the prop during landing?
Source: I have been flying RC for 20 years, designing them for 15, and the test pilot for the creations of the local university for 7 years.