VTOL to Airfoil Flight Conversion: new experiment!

[quadcoptersbyH]

Hello quadcopterforum, I'm glad to have found your site!
I am building a VTOL to Airfoil Flight converting aircraft as the description reads, and would like some help back checking my setup if you could help out!

I have lots of experience with gliders and small powered planes, but little experience building quadcopters.

In a nutshell, what I am building is a quadcopter with an airfoil body around it, and gimbaled(one axis) motors. The vehicle will take off and be able to maneuver like a quad, but will also be able to transition to forward flight by gimbaling these motors forward in midair.

People have done things like this before, I'm just trying out this build project for myself!

So
If I am expecting my frame weight to be 600g, and am planning to use NTM 800kv motors with 10" span propellers, will I be able to take off in quadmode? or will I stay sadly on the ground? My flight controller is a cc3d. besides that, the parameters are undecided.

what do you think?

 

[holtneil]

Hi mate I had a heavy quad 1.2kg on 4 NTM 1100kv motors and 10x4.7 props , you cant keep it on the floor it has so much power it would go from ground to 80 feet in 3 seconds
Use ecalc.com to test set ups
What you need to do is weight of quad ( flight weight inc battery) plus 1/2 again then divide by the numbers of motors , this will give the the thrust you need from each motor ( in grms)

 

[quadcoptersbyH]

Thanks holtneil, for pointing me to that tool.

It seems those motors would not serve for my purpose since my entire setup was too heavy. The frame alone I expect to be 1kg when all is said and done. Plus 4 motors at 110-120 g, plus battery 170-180g plus another misc 200g. Total weight between 1800g and 2kg.

Another set of motors that could work are the NTM3536 1400kv motors (nicely priced at 20 bucks each!) with 10" propellers and 6000mah 30c lipo. The calculator tells me my flight time will be around 10 minutes at this configuration.

I will do my best to lighten up my rig so I get better performance. Still, I expect that in airplane mode this thing will haul some tuchus. 4 1400kv motors running 10" propellers to drive what is essentially a flying wing? It's gonna go.

any comments from you guys about this setup?

 

[holtneil]

Hi mate using a high kv motor with big props can make motors and/or esc to run hot ,you will have a big amp loading on the esc with the bigger props , normally a high kv motor small props low kv big props , but if ecalc says it good to go then it will be ok

 

[quadcoptersbyH]

Thanks for the reply!

Interesting videos, I had never seen these particular quads before. The idea is right on the money for the second one, but with the addition of turning the motors forward and keeping control surfaces on the wing to fly in that configuration. I have to say, the price point for those toys is making me second think scratch building and just buying something similar and modifying it. I don't like being stingy on experiments and projects like this, but my estimated costs for the whole thing are reaching up to 400 dollars, which is a bit steep if it ends up being unsuccessful.

As for the motor and propeller pairing, the calc is telling me that maximum power draw temp is estimated at 144 fahrenheit, but I don't typically trust online calculators 100%. This unfortunately doesn't give me safety margin of 50%, but I believe a safety margin of 20% before reaching what other people say is dangerous temps (~170 degrees and above) might be enough. I am a little worried about the surrounding foam body. If it really is epp like advertised, then it won't be a problem, but if its epo then I will have to figure out a way to thermally isolate.

The amp loading the calc is telling me is ~32 amps max, which is big but there are ESCs that handle that, still I hate paying 60-80 bucks for every set of components! And if one fails, or I have a bad crash, it will be hard to motivate a quick rebuild!

well anyways, that's enough bellyaching about the wallet
Here's the parts list I've assembled so far. what do you think?:
(1)HobbyKing WickedWing slope flying combat wing (rebranded Bee2 12200mm span) $60 flying weight 510-650g
(1)OpenPilot cc3d flight controller $31 5.7g
(4)NTM propdrive 3536 1400kv/550w brushless motors $21*4=$84 117*4=468g
(2)4 propeller set ccw and cw 9" span 4.7" pitch $6 (or more expensive carbon fiber for $12 for only four) 45g
(1)Turnigy 9x 9ch transmitter and receiver $60
(4)Turnigy AE-30A esc $52 25*4=100g
(1)Zippy flightmax 8000mah 4s1p 30c battery $63 845g
(3)metal gear servos $15-30 3*33~100g
(1)battery charger (already obtained/belongs to lab=$0)

extra parts and costs $50
shipping cost allowance $50

Total cost $471, max possible cost with no failures probably <$500
Total weight 2213.7, almost exactly what I estimated max weight. WOOF, heavy. Maybe the wicked wing flying weight assumes servos..... in which case 2063(still big, we'll see).

I will get a very short flight time with this setup I think, calc says like 10 minutes quadcopter mode, but maybe it will be longer in the more efficient airplane mode, either way, 10 minutes is enough to make the proof of concept here I think.

Sorry for the long posts! I appreciate you looking through them. Half the fun of building RCs is designing them!

 

[holtneil]

Hi mate sound more like a tilt rotor an quad , but that got me thinking you can buy a tilt rotor so why cant we add 2 more motors so it has 4
Also the transmitter normally has a setting in the aero section for tilt motors , I just found this

 

[quadcoptersbyH]

Good idea. I will look into it this afternoon and reply back with the results!