calculating the forces acting on the motor axis

[shekubob]

I would like to know how to calculate the forces acting on the motor axis as a result of air resistance to the propeller
I'm interested in which formula I can calculate the impulse that is generated depends on the size of the propeller

 

[With The Birds]

Which axis?

 

[Jayfdee]

I am no expert in these matters, but I would think the relationship between speed and torque of the motor shaft and lift generated is completely non linear, and probably very difficult to mathmatically correlate.
Bit like a centrifugal liquid pump curve, the prop is basically the same, ie an impeller moving fluids.
Sorry not much help, only guessing, and of course when moving forward you need to consider wind resistance, and Newtons second law if accelerating, too complex for me.

 

[shekubob]

Which axis?

The motor

 

[shekubob]

I am no expert in these matters, but I would think the relationship between speed and torque of the motor shaft and lift generated is completely non linear, and probably very difficult to mathmatically correlate.
Bit like a centrifugal liquid pump curve, the prop is basically the same, ie an impeller moving fluids.
Sorry not much help, only guessing, and of course when moving forward you need to consider wind resistance, and Newtons second law if accelerating, too complex for me.

Thanks
I want to design a drone in large dimensions and at such sizes the torque that the propeller drive is no longer negligible so I need to know how to calculate s oi can choose the right motor

 

[With The Birds]

The motor

I was thinking more x,y or z. It seems now from your later clarification what you are really trying to determine is thrust rating for your application. How much will the AC weigh (including your intended payload)?

 

[With The Birds]

Thanks
I want to design a drone in large dimensions and at such sizes the torque that the propeller drive is no longer negligible so I need to know how to calculate s oi can choose the right motor

The total thrust generated by all props needs to be at least twice the total AC weight, 3 or 4 to one is probably a better number to go for. Once you have that figured out frame dimensions and number of rotors is your next consideration. From there you can start looking at motor and prop choices.

What do you have in mind?

 

[shekubob]

I was thinking more x,y or z. It seems now from your later clarification what you are really trying to determine is thrust rating for your application. How much will the AC weigh (including your intended payload)?

i want around 300kg craft and payload

 

[With The Birds]

i want around 300kg craft and payload

Manned?

 

[shekubob]

The total thrust generated by all props needs to be at least twice the total AC weight, 3 or 4 to one is probably a better number to go for. Once you have that figured out frame dimensions and number of rotors is your next consideration. From there you can start looking at motor and prop choices.

What do you have in mind?

i started with the amount of thrust around 600kg this is craft and payload (400-300 kg)

 

[shekubob]

Manned?

yep 2 persons

 

[With The Birds]

Good luck. That’s a major project.

 

[shekubob]

Good luck. That’s a major project.

yes i know
i hoped to find some information
but a good word is always warms your hearth

 

[With The Birds]

yes i know
i hoped to find some information
but a good word is always warms your hearth

What is your budget? Is it based on a kit? Some Chinese mob (cant recall the name) had a one manned LiION UAV at CES, max payload including one person 100kg and max flight time 20mins or something close to that and they were saying $200K US as the expected price. There is no easy or cheap way to do this.

 

[shekubob]

What is your budget? Is it based on a kit? Some Chinese mob (cant recall the name) had a one manned LiION UAV at CES, max payload including one person 100kg and max flight time 20mins or something close to that and they were saying $200K US as the expected price. There is no easy or cheap way to do this.

i seen that i first plan the prototype and then start construction bit by bit

 

[With The Birds]

i seen that i first plan the prototype and then start construction bit by bit

If I remember right one horsepower driving an efficient propellor might give you 25 pounds of thrust.

 

[joeyjan19]

I would like to know how to calculate the forces acting on the motor axis as a result of air resistance to the propeller
I'm interested in which formula I can calculate the impulse that is generated depends on the size of the propeller

Look into NASA, propeller thrust, it might have it.

 

[N017RW]

Here’s a discussion that may make things less clear

Thrust VS. Horsepower? - Airliners.net

 

[joeyjan19]

Here’s a discussion that may make things less clear

Thrust VS. Horsepower? - Airliners.net

Propeller Thrust

To help confuse the entire situation.

 

[Sesmith016]

It may also help to look into engineering statics and dynamics