Help with RC plane project

Thread Starter

-live wire-

Joined Dec 22, 2017
918
Hi so I would like to make my own RC plane. I want to make one that not only functions, but also works well. I would like it to be large, have a long battery life, be able to maneuver decently, and be able to hold a bit of extra weight if i want to attach stuff to it.

I am thinking for the design, it would look something like this drawing (pretty bad and not to scale):
1627074907134.png
For a rough idea of the size, the propellers would be 12-16 in. And these are my very rough estimates of power use and thrust (taken from motor's datasheet).

1627073777810.png

I need help with a couple things. First of all, I need to know if my overall design is decent given the size of everything. Does using two ailerons, two elevators, and a rudder make sense or is there a better way to control the steering?

Also, I will need help finding parts and deciding on a material to use. And maybe I'm missing something or being unrealistic so if thats the case feel free to let me know.
 

MaxHeadRoom

Joined Jul 18, 2013
23,585
Have you any RC experience similar to this so far?
You could also contact any local RC clubs which are usually eager to help new comers!
 

Thread Starter

-live wire-

Joined Dec 22, 2017
918
Have you any RC experience similar to this so far?
You could also contact any local RC clubs which are usually eager to help new comers!
I have a drone and have flown a bunch of drones before, but don't have as much experience with rc planes. Also idk about many local rc clubs.
 

Audioguru again

Joined Oct 21, 2019
3,499
I fly RC airplanes that are made from foam and are ready to fly. They are less than the "illegal" weight of 250 grams.
Next month they are coming out with a larger Ultrix one that is different to most airplanes. They already are selling a smaller one that I do not have.
The airplane has 2 powerful motors that can make the airplane hover and do vertical climbing. The two motors have differential thrust instead of a rudder that can make advanced aerobatic maneuvers like fast flat spins and more. It has elevons. Edited.
The receiver has a switchable "gyro" that they call SAFE that can allow you to turn it on to avoid a crash. It also smooths turbulence. Its specs are here and there is a video here. https://www.horizonhobby.com/product/ultrix-600mm-bnf-basic/EFL02250.html
 

Attachments

Last edited:

LowQCab

Joined Nov 6, 2012
1,078
How important is it to you to have the Plane look like
a down-sized version of a conventional full-sized Plane ?
This goes hand-in-hand with "crash-worthiness".
A 3 X 3 square sheet of Foam-Board will fly amazingly well.

What is your desired Stall-Speed ?
If you've never flown an RC-Plane before,
You will want the lowest Stall-Speed Plane that You can create.

What is your desired maximum-Air-Speed ?
More than ~30-mph is for highly experienced Pilots only.

Do You expect it to do Acrobatic-Maneuvers,
or do You want maximum, hands-off, Stability ?

Do You actually want a proper Camera-Platform ?

What is the largest Wing-Span dimension that you can accommodate for storage ?

What is the heaviest object that You would like to carry ?
( weight is the mortal enemy of Planes too )
Find-out how to calculate Wing-Loading.

Drone experience is great to have, but Airplanes are a different animal.
Before You start making huge plans in your imagination, go to
https://www.flitetest.com
Buy a cheap beginner Foam-Plane and get really good at flying it,
IT AIN'T AS EASY AS IT LOOKS, just like learning to fly a Drone in Acro-Mode.
And things seldom work the way You thought they would.
These Planes are so cheap and easy, that You can build ~10 of them for the cost
of the design that You will eventually decide that You want.
FlightTest also has an excellent YouTube Channel.

For heavy lifting, nothing can touch 2-Flying-Wings stacked together,
this gives You tons of Wing-Area for the minimum weight penalty, and Wing-Span,
this design also protects your expensive Carbon-Fiber-Props from hitting the ground or trees,
and makes the Plane safer around People.
( the Props are completely protected by being mounted between the 2 Wings )
Stacked Flying-Wings also makes VTOL a practical possibility as long as You have enough Thrust.
4-Motors between the Wings is natural and easy with this design.

Motor and Prop selection, and the reasons why, is quite different for Drones and Planes.
.
.
.
 

Thread Starter

-live wire-

Joined Dec 22, 2017
918
How important is it to you to have the Plane look like
a down-sized version of a conventional full-sized Plane ?
-looks dont matter I just thought that a conventional design would be good because people use it a lot, but would be open to other designs too.

What is your desired Stall-Speed ?
If you've never flown an RC-Plane before,
You will want the lowest Stall-Speed Plane that You can create.
-yeah I haven't really considered that but definitely should. I guess for minimizing the cost of a crash and easy control then I would definitely want a slower stall speed.

What is your desired maximum-Air-Speed ?
More than ~30-mph is for highly experienced Pilots only.
-I would want it to be faster, maybe 50-100 mph max. But since you suggest a slower speed until you gain experience, I will start out limiting the speed to ~30mph.

Do You expect it to do Acrobatic-Maneuvers,
or do You want maximum, hands-off, Stability ?
-I'm not looking to do a bunch of acrobatic maneuvers. but it would be nice if it was responsive and could turn quickly based on the input.

Do You actually want a proper Camera-Platform ?
I might want to add one in the future but I want to start off more simple and have no camera.

What is the largest Wing-Span dimension that you can accommodate for storage ?
-this is not a concern, probably 10-12 ft max
What is the heaviest object that You would like to carry ?
( weight is the mortal enemy of Planes too )
-I would like to be able to add a bunch of stuff onto it in the future, like a bright light or some other things. so maybe another 2-5kg of stuff max. I will make sure to keep in mind that weight is definitely an issue.


Drone experience is great to have, but Airplanes are a different animal.
Before You start making huge plans in your imagination, go to
https://www.flitetest.com
Buy a cheap beginner Foam-Plane and get really good at flying it,
IT AIN'T AS EASY AS IT LOOKS, just like learning to fly a Drone in Acro-Mode.
And things seldom work the way You thought they would.
These Planes are so cheap and easy, that You can build ~10 of them for the cost
of the design that You will eventually decide that You want.
FlightTest also has an excellent YouTube Channel.
-ok I will first try to start on a smaller scale with some foam planes, and get some experience

For heavy lifting, nothing can touch 2-Flying-Wings stacked together,
this gives You tons of Wing-Area for the minimum weight penalty, and Wing-Span,
this design also protects your expensive Carbon-Fiber-Props from hitting the ground or trees,
and makes the Plane safer around People.
( the Props are completely protected by being mounted between the 2 Wings )
Stacked Flying-Wings also makes VTOL a practical possibility as long as You have enough Thrust.
4-Motors between the Wings is natural and easy with this design.
Motor and Prop selection, and the reasons why, is quite different for Drones and Planes.
-based on what you described, that design sounds very appealing. not damaging propellers, keeping them out of the way of people, maximizing wing area, and vtol all sound great. what materials would this kind of design use though? balsa wood, foam, thin plastic, or something else?
 

Tonyr1084

Joined Sep 24, 2015
6,241
Physics 101: The more weight you want to lift the more power you're going to need. The faster you want to go the more power you're going to need. A bigger battery can provide more power, but it's weight negates the benefit of longer battery life because, as stated first off, the more weight you want to lift the more power you're going to need. If you sacrifice speed you can lift more, but the flight will be shorter - because - the longer you want to be aloft the more power you're going to need.

It's a catch 22. The more you want the more you'll have to carry. The more you have to carry the more you limit your endurance. Sacrifice one for the other because you can't have both. Not yet anyway.
 

LowQCab

Joined Nov 6, 2012
1,078
The difference between 50 and 100 MPH is massive.
It also has a tremendous effect on how everything about the Plane is designed.
It's the difference between almost an Hour of Flight-Time vs ~5-Minutes.
It's also the difference between a ~10-MPH Stall-Speed vs a ~25-30-MPH Stall-Speed.
It also requires smaller-diameter/higher-Pitch Props, and less efficient, high-KV-Motors,
that have very little low-speed grunt-power which is needed for short take-offs and heavy-loads.

~5-kg, that's around ~11-Pounds, this requires a seriously BIG Plane.
With 4 of the Motor/Prop combos You selected above, you'll struggle just to get off the ground.
With a Plane, You need total Thrust that is at least equal to the weight of the Plane plus Payload.
You're probably going to need a 20-pound Plane to get 10-Pounds of Payload off the ground,
so that's at least ~30-pounds of Thrust, this will get into some serious Money very fast.
Check-out the specs on this Motor/Prop Combo, ( you'll need 4 of them ) ................
T-Motor Antigravity 6007 KV160 a .pngP21 X 6.3 Prop .jpgPerformance Chart .pngAPD PDB  FLAT  .pngAs for materials,
the ideal arrangement would be to find someone with
a really big "Hot-Wire" Foam-Cutting setup to make You some custom Wing Sections
that can be disassembled for transportation.
Most likely, the largest dimension is going to be around ~48", so 4-sections would make
You 2- 8-foot wide, ~8-inch thick, Foam-Wings that will be stacked roughly ~24-inches apart,
and spaced and attached together with 3- 4-inch-thick vertical sections.
All of the various parts will be held together with 1"-diameter Carbon-Fiber-Tubes that
run the full length of the Wings, 2-Tubes per Wing.
2 more of these same Carbon-Fiber-Tubes will make great Tail-Booms as well.

This will give You over 64-square-feet of Wing surface area for
a total of about ~30-Pounds, which equals roughly 0.5-pounds per sq.-ft. ,
this should put the Stall-Speed at less than ~15-MPH,
and yet still have enough Thrust in reserve for straight-up-Vertical-Flight.
This is probably going to be a fairly high-drag design,
so top-speed will probably be around ~45- ~50-MPH,
and around ~10-MPH continuous, straight-up-Vertical,
with a casual Cruise-Speed being around ~20 to ~25-MPH.

No Rudder-Control is needed, Differential-Motor-Thrust will provide Yaw-Control.
A Fixed Vertical-Stabilizer of some sort is still required.

The Elevator should be ~48-inches X ~24-inches,
and made from a Symmetrical, Foam, Air-Foil-shape, and be fully articulated, and balanced.
Use 2 of the largest "Metal-Gear" Heavy-Duty-Servos that You can find for the Elevator.
Mount the Elevator ~6-feet back from the trailing edge of the TOP-Wing .
The Pivot for the Elevator should be 2-Carbon-Fiber Tubes, one inside the other.
The outside Tube will be fitted into a full width hole, cut with a Hot-Wire-Machine,
in the center of the Symmetrical Foam Airfoil, and Epoxied in place.
A loose-fit is a good thing to prevent any binding.

The top and bottom Wings should have Full-Width "Flaperons",
with 2-Heavy-Duty, Metal-Gear-Servos per ~24-inch section.
That's 4 on the top-Wing, and 4 on the bottom-Wing.
The Flaperons should be made from Corrugated-Plastic-Poster-Board material,
with the internal ribs oriented front to rear,
and should extend at least ~8 to ~10-inches past the trailing-edge of each Wing-Section.
A 1/4-inch Carbon-Fiber Rod should be Taped to the Pivot-Edge to provide some rigidity.
Use only 2- light-weight Brass-"Gate-Hinges" per Flap to prevent any binding from Wing-flex,
the Control-Horns for the Servo-Linkage should mount directly to the hinges,
and a large (3" X 3"), thin, Aluminum backing plate should be made for both sides of
the Flap to prevent crushing by the Hinge mounting screws, Epoxy them in place.
Fill the hollow corrugations in the Flaps with Epoxy-Glue in the area where
the Hinges will be screwed to the Flap to prevent crushing,
this will also add substantial rigidity to the Flap.

Remember that all heavy objects must be mounted within the front 1/3 of the Bottom-Wing,
and, that the Plane MUST balance perfectly level at
approximately 1/3 of the distance back from the front-edge of the Top-Wing.
You may even have to ADD WEIGHT to the nose to achieve this balance,
if it's not perfectly balanced,
it will either be a total wallowing PIG to fly, (nose-heavy),
or completely out of control, and impossible to land without crashing, (tail-heavy).
Having the Center of Balance off by just ~3-inches can
make the Plane miserable, or impossible, to fly.

Use a Holybro Kakute F7 V1.5 Flight-Controller with the latest "I-Nav" Software and
let the FC do all the flying and stabilizing until You get used to flying in "Acro-Mode".
All the same stuff used in Drones also works in Planes,
even including "Return-to-Home" functions,
just totally different.
.
.
.
 

Thread Starter

-live wire-

Joined Dec 22, 2017
918
Physics 101: The more weight you want to lift the more power you're going to need. The faster you want to go the more power you're going to need. A bigger battery can provide more power, but it's weight negates the benefit of longer battery life because, as stated first off, the more weight you want to lift the more power you're going to need. If you sacrifice speed you can lift more, but the flight will be shorter - because - the longer you want to be aloft the more power you're going to need.

It's a catch 22. The more you want the more you'll have to carry. The more you have to carry the more you limit your endurance. Sacrifice one for the other because you can't have both. Not yet anyway.
That is true lol
 

Thread Starter

-live wire-

Joined Dec 22, 2017
918
The difference between 50 and 100 MPH is massive.
It also has a tremendous effect on how everything about the Plane is designed.
It's the difference between almost an Hour of Flight-Time vs ~5-Minutes.
It's also the difference between a ~10-MPH Stall-Speed vs a ~25-30-MPH Stall-Speed.
It also requires smaller-diameter/higher-Pitch Props, and less efficient, high-KV-Motors,
that have very little low-speed grunt-power which is needed for short take-offs and heavy-loads.

~5-kg, that's around ~11-Pounds, this requires a seriously BIG Plane.
With 4 of the Motor/Prop combos You selected above, you'll struggle just to get off the ground.
With a Plane, You need total Thrust that is at least equal to the weight of the Plane plus Payload.
You're probably going to need a 20-pound Plane to get 10-Pounds of Payload off the ground,
so that's at least ~30-pounds of Thrust, this will get into some serious Money very fast.
Check-out the specs on this Motor/Prop Combo, ( you'll need 4 of them ) ................
View attachment 244285View attachment 244286View attachment 244287View attachment 244288As for materials,
the ideal arrangement would be to find someone with
a really big "Hot-Wire" Foam-Cutting setup to make You some custom Wing Sections
that can be disassembled for transportation.
Most likely, the largest dimension is going to be around ~48", so 4-sections would make
You 2- 8-foot wide, ~8-inch thick, Foam-Wings that will be stacked roughly ~24-inches apart,
and spaced and attached together with 3- 4-inch-thick vertical sections.
All of the various parts will be held together with 1"-diameter Carbon-Fiber-Tubes that
run the full length of the Wings, 2-Tubes per Wing.
2 more of these same Carbon-Fiber-Tubes will make great Tail-Booms as well.

This will give You over 64-square-feet of Wing surface area for
a total of about ~30-Pounds, which equals roughly 0.5-pounds per sq.-ft. ,
this should put the Stall-Speed at less than ~15-MPH,
and yet still have enough Thrust in reserve for straight-up-Vertical-Flight.
This is probably going to be a fairly high-drag design,
so top-speed will probably be around ~45- ~50-MPH,
and around ~10-MPH continuous, straight-up-Vertical,
with a casual Cruise-Speed being around ~20 to ~25-MPH.

No Rudder-Control is needed, Differential-Motor-Thrust will provide Yaw-Control.
A Fixed Vertical-Stabilizer of some sort is still required.

The Elevator should be ~48-inches X ~24-inches,
and made from a Symmetrical, Foam, Air-Foil-shape, and be fully articulated, and balanced.
Use 2 of the largest "Metal-Gear" Heavy-Duty-Servos that You can find for the Elevator.
Mount the Elevator ~6-feet back from the trailing edge of the TOP-Wing .
The Pivot for the Elevator should be 2-Carbon-Fiber Tubes, one inside the other.
The outside Tube will be fitted into a full width hole, cut with a Hot-Wire-Machine,
in the center of the Symmetrical Foam Airfoil, and Epoxied in place.
A loose-fit is a good thing to prevent any binding.

The top and bottom Wings should have Full-Width "Flaperons",
with 2-Heavy-Duty, Metal-Gear-Servos per ~24-inch section.
That's 4 on the top-Wing, and 4 on the bottom-Wing.
The Flaperons should be made from Corrugated-Plastic-Poster-Board material,
with the internal ribs oriented front to rear,
and should extend at least ~8 to ~10-inches past the trailing-edge of each Wing-Section.
A 1/4-inch Carbon-Fiber Rod should be Taped to the Pivot-Edge to provide some rigidity.
Use only 2- light-weight Brass-"Gate-Hinges" per Flap to prevent any binding from Wing-flex,
the Control-Horns for the Servo-Linkage should mount directly to the hinges,
and a large (3" X 3"), thin, Aluminum backing plate should be made for both sides of
the Flap to prevent crushing by the Hinge mounting screws, Epoxy them in place.
Fill the hollow corrugations in the Flaps with Epoxy-Glue in the area where
the Hinges will be screwed to the Flap to prevent crushing,
this will also add substantial rigidity to the Flap.

Remember that all heavy objects must be mounted within the front 1/3 of the Bottom-Wing,
and, that the Plane MUST balance perfectly level at
approximately 1/3 of the distance back from the front-edge of the Top-Wing.
You may even have to ADD WEIGHT to the nose to achieve this balance,
if it's not perfectly balanced,
it will either be a total wallowing PIG to fly, (nose-heavy),
or completely out of control, and impossible to land without crashing, (tail-heavy).
Having the Center of Balance off by just ~3-inches can
make the Plane miserable, or impossible, to fly.

Use a Holybro Kakute F7 V1.5 Flight-Controller with the latest "I-Nav" Software and
let the FC do all the flying and stabilizing until You get used to flying in "Acro-Mode".
All the same stuff used in Drones also works in Planes,
even including "Return-to-Home" functions,
just totally different.
.
.
.
Ok given the cost and scale, I might want to size things down then. I'll be busy for a bit with other things so sorry if I take a little while to respond or follow up.
 

Lo_volt

Joined Apr 3, 2014
217
I'll note that for a beginner a single prop plane will be easier to learn. I'll also suggest you learn about flying/piloting an airplane. It's not as simple as driving a vehicle on the ground. You must learn what each control does and how to use the controls to do what you want the plane to do. There's plenty of info on the web.

Start small and simple. Then you can learn and decide whether you want to build bigger or add features.
 
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