Help! Best wing type for payload

[martijn10022]

Hey folks,

I'm planning on building an RC plane not wider or longer than 1m.
Now I was given the challenge to carry as much payload as possible, I will compete with others in a few months. This brought me here, to gain some knowledge from the experienced builders.

I'll be using a single propeller engine, and the payload will be placed inside the fuselage.
I attached an image with details about the propulsion

Now what is the best wing type for such a plane?
I saw people recommending versa wings for payloads, but with other variables such as power and weight.
I also saw flat-bottom wings on YT but under-cambered were also recommended.
But I know there are many other profiles.
What should I choose?

Any advise is welcome!

 

[The Hangar]

I’ve heard wings are good platforms as well, so depending on what size of motor you can use, scale the versa to the right size.
Have fun!

 

[Merv]

For heavy lifting, I'd recommend a simple, traditional plane, something like this one. Go with a flat bottom wing and make it as large as you can. Make it at least 15% thick. I'm thinking 39 inches long by 13 inches wide and 2 inches thick. A large, thick wing will carry the most weight.

I would build several wings from foam board and test them.

 

[Hai-Lee]

You mentioned a set wing span but not the type of plane required or its wing layout.

With short span long cord wings you would need to consider putting fences on the wing to reduce the sideways slipping of the airflow which can cause a cause a loss of lift.

With a short span you could make it a biplane thereby increasing the lifting area and the overall lift!

As a standard tail arrangement is somewhat parasitic, a lifting/flying tail of increased area and span could add valuable lift. This tail could be in the standard tractor position or even in the canard position.

With a large area lifting tail on a biplane you could get could get effectively 2 to 3 times the lift of a conventional design but careful attention would be required in setting the incidence angles of the flying surfaces to obtain best lift and control.
The use of flaps/flaperons/elevons would enhance lift further.

Mind you such a design would not fly with any great speed and it could almost take off vertically on propeller thrust alone when not carrying the payload..

If the fuselage is to support landing gear for take off and landing with the payload a slightly different arrangement could be entertained to minimise the size and weight of the undercarriage.

Just a few thoughts on high lift designs!

Have fun!

 

[BATTLEAXE]

If your looking at a 1 meter wingspan, @Hai-Lee is right you could easily increase your lift by playing around with a long wing chord. Even 20-25 cm would be good. You could also work with a flat bottom/under camber design like most FT planes with the last 10-15 cm of the wing tips being under cambered, that way the tips will stall last, better for stabilization. Wing tip fences will help eliminate wash out so you will get the most effective lifting surface area possible. A high wing airframe will also help with stabilization using the pendulum effect of the weight of the payload under the wing. If this is all balanced right at 25-33% of the total wing chord from the leading edge with payload in place under the center of gravity so no matter how heavy the pay load is it will always balance within reason.

With all this being the basic stuff, adding flaps, leading edge slats or vortex generators this has the potential to be substantial lifter. The motor and prop will have tons of power and torque to do the job. You did say you need to carry the payload INSIDE the fuse, do you know what the payload is, like a bag of dried beans or is it water in a bottle, is it weights? This info would help for sure to carry this on further for you but it sounds like this could really be a fun build. Keep us posted

 

[Merv]

Many contests use a ratio, the payload / weight of the plane. Some also have maximum and minimum payloads. In this contest the lightest plane that can lift the minimum payload will win.

 

[martijn10022]

For heavy lifting, I'd recommend...
...

Thanks! This guy really knows what he is talking about.

 

[martijn10022]

You mentioned a set wing span but not the type of plane required or its wing layout.

With short span long cord wings you would need to consider putting fences on the wing to reduce the sideways slipping of the airflow which can cause a cause a loss of lift.

With a short span you could make it a biplane thereby increasing the lifting area and the overall lift!

As a standard tail arrangement is somewhat parasitic, a lifting/flying tail of increased area and span could add valuable lift. This tail could be in the standard tractor position or even in the canard position.

With a large area lifting tail on a biplane you could get could get effectively 2 to 3 times the lift of a conventional design but careful attention would be required in setting the incidence angles of the flying surfaces to obtain best lift and control.
The use of flaps/flaperons/elevons would enhance lift further.

Mind you such a design would not fly with any great speed and it could almost take off vertically on propeller thrust alone when not carrying the payload..

If the fuselage is to support landing gear for take off and landing with the payload a slightly different arrangement could be entertained to minimise the size and weight of the undercarriage.

Just a few thoughts on high lift designs!

Have fun!

Wow this really will help. I will definitely make the tail generate lift! This helps a lot.
I'm still figuring out how to design the landing gear construction, I want as least drag as possible.

 

[BATTLEAXE]

Wow this really will help. I will definitely make the tail generate lift! This helps a lot.
I'm still figuring out how to design the landing gear construction, I want as least drag as possible.

Do you have to take off and land on the gear or can you hand launch?

 

[martijn10022]

If your looking at a 1 meter wingspan, @Hai-Lee is right you could easily increase your lift by playing around with a long wing chord. Even 20-25 cm would be good. You could also work with a flat bottom/under camber design like most FT planes with the last 10-15 cm of the wing tips being under cambered, that way the tips will stall last, better for stabilization. Wing tip fences will help eliminate wash out so you will get the most effective lifting surface area possible. A high wing airframe will also help with stabilization using the pendulum effect of the weight of the payload under the wing. If this is all balanced right at 25-33% of the total wing chord from the leading edge with payload in place under the center of gravity so no matter how heavy the pay load is it will always balance within reason.

With all this being the basic stuff, adding flaps, leading edge slats or vortex generators this has the potential to be substantial lifter. The motor and prop will have tons of power and torque to do the job. You did say you need to carry the payload INSIDE the fuse, do you know what the payload is, like a bag of dried beans or is it water in a bottle, is it weights? This info would help for sure to carry this on further for you but it sounds like this could really be a fun build. Keep us posted

Thanks! Definitely going to use a long chord. I'm indeed going to look into wingtip devices, also stall-fences might come in handy I think when having a large wing area.
So you'd recommend a wing that has a flat bottom from the root to about 10-15 cm from the tip and then transforms into an under-cambered wing?

These are the rules I was given for the payload:

 

[martijn10022]

Many contests use a ratio, the payload / weight of the plane. Some also have maximum and minimum payloads. In this contest the lightest plane that can lift the minimum payload will win.

This contest has 2 parts:
1. Entering the contest by flying the path safely, without payload.
2. Taking as much payload as possible on yet another safe flight.

I forgot to mention this is for a project at my school. So I'm with 6 other students. We study 2nd of 4 years of aeronautical engineering.

 

[BATTLEAXE]

Thanks! Definitely going to use a long chord. I'm indeed going to look into wingtip devices, also stall-fences might come in handy I think when having a large wing area.
So you'd recommend a wing that has a flat bottom from the root to about 10-15 cm from the tip and then transforms into an under-cambered wing?

These are the rules I was given for the payload:
View attachment 157406

So all you need to do is land on the gear, looks like you can hand launch. Use wire skids for landing gear, next to no drag in flight

 

[martijn10022]

I’ve heard wings are good platforms as well, so depending on what size of motor you can use, scale the versa to the right size.
Have fun!

Thanks, next week I will get a lecture on how to tune such a motor to optimum performance

 

[Spacefarer]

Remember that if you make the tail generate lift, it will push your nose down the more you speed up.

 

[martijn10022]

So all you need to do is land on the gear, looks like you can hand launch. Use wire skids for landing gear, next to no drag in flight

My school supplies the electronics, it is not allowed to use extra electronics or modify any. So it looks like it is going to be a fixed landing gear, since unfolding the landing gear would require another device.

 

[BATTLEAXE]

Wow this really will help. I will definitely make the tail generate lift! This helps a lot.
I'm still figuring out how to design the landing gear construction, I want as least drag as possible.

This lifting tail can be a double edged sword. Although it will create lift, it might also create enough lift to pitch the nose forward and bring the plane down making it harder to maintain a 3 meter level flight

Wow this really will help. I will definitely make the tail generate lift! This helps a lot.
I'm still figuring out how to design the landing gear construction, I want as least drag as possible.

The rules also don't say you can't double your lifting surface by using a biplane design, two wings are better then one. Both wings are fixed to the CG point generating lift in the same area of your payload so balance will always be perfect

 

[martijn10022]

Remember that if you make the tail generate lift, it will push your nose down the more you speed up.

That makes sense, I will have to take that into account. Thanks

 

[BATTLEAXE]

My school supplies the electronics, it is not allowed to use extra electronics or modify any. So it looks like it is going to be a fixed landing gear, since unfolding the landing gear would require another device.

I am not saying using retracts, or even wheels at all, just fixed wire skids installed on the bottom of the fuse, like Santa's sleigh

 

[martijn10022]

This lifting tail can be a double edged sword. Although it will create lift, it might also create enough lift to pitch the nose forward and bring the plane down making it harder to maintain a 3 meter level flight
The rules also don't say you can't double your lifting surface by using a biplane design, two wings are better then one. Both wings are fixed to the CG point generating lift in the same area of your payload so balance will always be perfect

Exactly, I think this will be added to the design. The CG would be between the wing and the tail, I would have to calculate the difference in lift for both wings for when speeding up.

 

[BATTLEAXE]

Exactly, I think this will be added to the design. The CG would be between the wing and the tail, I would have to calculate the difference in lift for both wings for when speeding up.

Have you started building yet, or even have a rough draft