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Very LARGE Heavy Load Glider Electronics

#1
I am building a 2 x 15 ft dual wingspan glider (100 sq ft wing area, high lift airfoil) to carry a 15 lb load and would like recommendations on what servos, receiver, battery and voltage control to use for an elevon set up. Flight times would typically be less than 1 hr. No, the load will not be dropped. Recommended model numbers would be great. I have a Flysky 6 channel transmitter and receiver but don’t have to use them.
 

The Hangar

Well-known member
#2
Wow - that’s a big glider! What type of glider are you planning on building? When you say elevons are you saying it won’t have a tail? This is what an elevon setup would be...
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As far as servos go, I’d go for something like savor or hitec high torque servos. @SquirrelTail can link you to some specific ones he uses in his large planes. This isn’t a powered glider, right? So you can just get a large castle bec that can handle the amperage draw of however many servos you’re using , and hook that up to your receiver. You’ll probably want something like a 5000 mah 3s pack to power the bec and servos with.
 

Hai-Lee

Old and Bold RC PILOT
#3
There is no rule that says a control surface must be driven by a single servo or even that the control surface cannot be a number of control surfaces all adjacent to each other.
You could easily use 2 separate servos on each split/divided control surface, (2 pieces), and use a "Y" harness to connect them to the receiver.

Have fun!
 

quorneng

Well-known member
#5
Without some idea/sketch of the actual layout of your design (dual wing glider?) it is hard to judge what would be realistic or appropriate.
 

Piotrsko

Well-known member
#6
Flying for up to an hour? It's either slope or one massive winch launch. 15 ft span will be exciting during landing on most slopes to say the least. 4 size "D" batteries as an airborne pack should be enough power.
 
#7
574B7533-7282-470B-B7F3-EDEB1FD17378.jpeg

Something like this...no prop. Trying to keep the wing loading at 0.5 lb per sq ft

Okay....zeroing in on a plan. I like the dual aileron servo idea...more likely to need that size in future, this size plane will be a once and done I think....so..
Battery Turnigy 5000 3 cell @ 11 volts and 12 oz weight.. if I reduce the time to a half hour can I go smaller?
Bec Castle 15 or 20 amp
Will My Flysky ia6b receiver will handle the amps to ?
two Hitech HS-645MG High Torque, Metal Gear Premium Sport Servo on a y connector per wing dual aileron/elevator ... total of four servos
 

Piotrsko

Well-known member
#8
The receiver only has to sink signal to the servos, not a lot of power used there. Reciever can provide control signal to at least 5servos a channel. The receiver bus should be adequate for a couple amps continuously, but a secondary bus could be warranted if the servos draw much more. @SquirrelTail has the answer. I don't run BEC on my gliders. Not worth the complexity. 4AA cells run me about 2hours flight time.
 

SquirrelTail

Well-known member
#9
The receiver only has to sink signal to the servos, not a lot of power used there. Reciever can provide control signal to at least 5servos a channel. The receiver bus should be adequate for a couple amps continuously, but a secondary bus could be warranted if the servos draw much more. @SquirrelTail has the answer. I don't run BEC on my gliders. Not worth the complexity. 4AA cells run me about 2hours flight time.
We run 8 of them powered off of 2 2s 3600 lipos
 
#10
I like the dual aileron servo idea...more likely to need that servo size in future, this size plane will be a once and done I think....so..
Battery Turnigy 2s 2400 or four AA batteries 6 volts
No Bec
My Flysky ia6b receiver
two Hitech HS-645MG High Torque, Metal Gear Premium Sport Servo (or similar) per wing dual aileron/elevator ... total of four servos on rear wing
Any other thoughts?
 

Hai-Lee

Old and Bold RC PILOT
#11
I like the dual aileron servo idea...more likely to need that servo size in future, this size plane will be a once and done I think....so..
Battery Turnigy 2s 2400 or four AA batteries 6 volts
No Bec
My Flysky ia6b receiver
two Hitech HS-645MG High Torque, Metal Gear Premium Sport Servo (or similar) per wing dual aileron/elevator ... total of four servos on rear wing
Any other thoughts?
I have lots of thoughts!
For a start I would definitely use a 5A BEC so that I can use standard low voltage equipment. In addition 5 A should be enough for a large number of servos or a number of large servos. AA batteries would not last if there is a requirement for a lot of control inputs. You need to remember that the terminal voltage folds quickly under load unless using NIMH and even then they can go flat and have their voltage collapse without warning. The weight of an external BEC would be insignificant considering the load.

I would ensure that all wings are mounted on the top of the fuselage as this allows the fuselage to take the forces of the landing and not the wings. In addition I would add dihedral to at least the rear wing or possibly even both wings.

Top mounted wings will also allow for adjusting the wing incidences more easily. Initially I would have the bird with the rear wing having a small amount of incidence, (around 1 to 2 degrees and the front wing slightly more. By increasing the incidences the wings will lift better regardless of the chosen airfoil and with the front wing having slightly more incidence when a stall occurs the nose will drop thereby avoiding a total loss of control and possibly a spin.

Control surfaces could be full span elevons though in my opinion outboard ailerons and inboard elevators would allow for easier setup, the use of cheaper servos and better handling.

DO not forget the bungee launch hook or the towline attachment point.

Just my thoughts!

Have fun!