Twin motor rc plane with one motor?

[skymaster]

Wow it looks like a lot of us have the same ideas but a little bit different. as for the pulleys you could always make the pulley with a V shape center that way the belt sinks into the groove and creates friction to it grabs the belt. so many ideas. you cold also try curtis youngblood system one motor to drive four blades but instead of four use it for only 2 here is the video this is way back.
Flite Test - Stingray 500 - OVERVIEW - YouTube

 

[agupt108]

cold also try curtis youngblood system one motor to drive four blades but instead of four use it for only 2 here is the video this is way back.
Flite Test - Stingray 500 - OVERVIEW - YouTube

Oh wow thank you! that seems like exactly what I am trying to do. Any idea what belt drive he used? it looks like a v-belt with notches? Thank you! Edit: it is a 222 drive belt with teeth.

 

[skymaster]

Oh wow thank you! that seems like exactly what I am trying to do. Any idea what belt drive he used? it looks like a v-belt with notches? Thank you! Edit: it is a 222 drive belt with teeth.

i think last time i checked on his website they sell replacement parts for the quad.
found a page with parts builds for the sting rays hope it helps.
Stingray 500 – CJ Youngblood Ent. (curtisyoungblood.com)

 

[skymaster]

by the way when i started looking for the info to show it to U guys and i saw the date on the video, the video was made 9 years ago dang i now feel old.

 

[agupt108]

i think last time i checked on his website they sell replacement parts for the quad.
found a page with parts builds for the sting rays hope it helps.
Stingray 500 – CJ Youngblood Ent. (curtisyoungblood.com)

Thank you! Though I think the drive belt will be a bit to small probably. By what i could find out, stingray uses flat teethed belt drive with gears that have teeth. Do you think that I should stick with the Stingray design or maybe use a v belt instead?

 

[quorneng]

Wood pulleys?
Assuming you can actually make them how do you propose to fix the wood pulleys to the shafts?
I do fear you are making life unduly difficult for yourself unless what you are actually proposing is a scale Wright flyer.

I do doubt if even two small size belts will be able to transmit the torque of a 2218 1180 kv motor on a 3s LiPo.
The bigger the belt the more energy it absorbs being flexed around the pulleys particularly at the high RPM such a motor runs at.

 

[agupt108]

Wood pulleys?
Assuming you can actually make them how do you propose to fix the wood pulleys to the shafts?
I do fear you are making life unduly difficult for yourself unless what you are actually proposing is a scale Wright flyer.

I do doubt if even two small size belts will be able to transmit the torque of a 2218 1180 kv motor on a 3s LiPo.
The bigger the belt the more energy it absorbs being flexed around the pulleys particularly at the high RPM such a motor runs at.

Ok. So then what would you suggest for the belt? The ones used on the quad like skymaster suggested? Now that I see that it is already tested and it works so might as well use what is already tested to be safe. And for the pulleys material? I was going to use balsa dowels but now I see it will be more complex. Thank you!
Also: this is interesting:

TDP-MR – CJ Youngblood Ent.

 

[Tench745]

Ok. So then what would you suggest for the belt? The ones used on the quad like skymaster suggested? Now that I see that it is already tested and it works so might as well use what is already tested to be safe. And for the pulleys material? I was going to use balsa dowels but now I see it will be more complex. Thank you!
Also: this is interesting:

TDP-MR – CJ Youngblood Ent.

You can buy aluminum pulleys and belts like he used on the Stingray. If you have access to any kind of 3D printing, that may also be an option.

On a different note, the prop recommendation I gave is based on a 1:1 gear ratio between the prop shafts and the motor. If you use pulleys of a different size it will affect how fast the prop shaft spins and thus change the size and pitch of prop you can run.

 

[quorneng]

I note those single motor quad copters use toothed belts.
Such belts can transmit by far the greatest power for their size of any belt but do require accurate toothed wheels and a very rigid frame with all shafts running in ball bearings as any slop will allow the belt to jump the wheel teeth.
Unfortunately they cannot be 'crossed'.
If you can live with both props going round the same way and if you could find suitable miniature belts and wheels it would provide the best "engineering" solution. Only a chain could give the same mechanical performance but with a weight penalty at model sizes.
If you want to stick with a simple belt I suspect you will have to experiment to see what does or does not work.

 

[agupt108]

Unfortunately they cannot be 'crossed'.

So in the Stingray design, I think they are still crossed in some way to provide counterrotating props. Thank you for guidance!

 

[agupt108]

You can buy aluminum pulleys and belts like he used on the Stingray. If you have access to any kind of 3D printing, that may also be an option.

On a different note, the prop recommendation I gave is based on a 1:1 gear ratio between the prop shafts and the motor. If you use pulleys of a different size it will affect how fast the prop shaft spins and thus change the size and pitch of prop you can run.

Yes...I think 3d printing will be a good option or aluminum pulleys (https://www.amazon.com/dp/B08QZ4365D/?tag=lstir-20 ?). Thank you again!

 

[quorneng]

By using a longitudinal drive shaft the belts only have to accept a 90 degree twist. Left and right belts are twisted the opposite way to give opposite prop rotation. It also means any losses from the twisting are shared equally between the two belts. A very neat solution. I don't think a single belt could be satisfactorily fully crossed.
I would still suggest it is likely to be more efficient using 4 individual motors.

 

[MasterVed]

Hello everyone! Great job on the progress made thus far. I've had a similar idea and after months of research, I was able to find this thread. Currently, I'm in the process of developing a design that aims to implement this idea. I'll be sharing updates on my work here as I strive to create a reliable, working prototype

 

[MasterVed]

Hello everyone! Great job on the progress made thus far. I've had a similar idea and after months of research, I was able to find this thread. Currently, I'm in the process of developing a design that aims to implement this idea. I'll be sharing updates on my work here as I strive to create a reliable, working prototype

UPDATE: Still working on the idea, developed a few 3d printed prototypes of the gear but i am unable to think of a efficient design. Typical battery (850 mAH 3 cell lipo battery) which was able to power one motor-one prop system for 8 minutes now can only power the one motor-two prop system for 3 and half minutes. Significant power is being drained, which results in slower flight time. Large 4s 2200 mAH is battery is currently being tested and currently shows the same effects. Significant power drain. Will have to use higher battery which inturn will require a larger plane and thus requiring more thrust to operator. This idea seem to be at a dead end, unless i can make the system more effective and make the batteries last longer. Side note. The system i made is really unstable as around 30 percent of the flights results in the gears sliping and causing one prop to fail and crashing the plane.
Future goals:
Detail more efficient design with less fraction or energy loss.
Larger plane design with safety designs for recovery in case of emergencies.
Test 6s battery with system.

 

[Thomas B]

While two props geared to one motor is doable, it is not the best solution at all. Two motors is much easier, likely lighter, far more reliable and the best solution.

I understand wanting to do something different or something your own way, but still, not the best solution.

 

[quorneng]

MasterVed
What motors are you using, particularly their kV.
What gears are you using?
Gears loose efficiency the faster they rotate so one way to improve overall efficiency is to gear the motor down and use larger slow turning props. A side benefit is such props can be more efficient at converting energy into thrust.
This way it is possible to create a geared prop system that over all is as efficient as a direct drive one,
A diagram of your twin prop system might be helpful.