how to improve motor thrust

J

justin_wang

Member
hi all
I need a motor of big thrust in RF，by installing parameter “prop pitch、prop diameter and torque generator”，but the thrust is not obviously improved.Could you tell me how to improve thrust？
 
justin_wang said:
hi all
I need a motor of big thrust in RF，by installing parameter “prop pitch、prop diameter and torque generator”，but the thrust is not obviously improved.Could you tell me how to improve thrust？
Click to expand...

More watts/HP mean more thrust potential. There are a few stinker in the propeller department. In term of efficiency.

What motor and prop are you using now?

How much thrust are you looking for and at what airspeed should the craft fly?
 
legoman said:
More watts/HP mean more thrust potential. There are a few stinker in the propeller department. In term of efficiency.

What motor and prop are you using now?

How much thrust are you looking for and at what airspeed should the craft fly?
Click to expand...
as the follow picture shows，the red line motor is working on my aircraft.
I am making a compound helicopter，when the main rotor's is closed,the rotor can be rotated by propeller which generates relative incoming flow,the rotation of rotor and fix wing can both produce lift.I am trying to determine relation between its velocity and stable RPM in rotation state.So,now,I don't know that how much is final speed needed.to achieve good result,I want to test its speed and stable RPM.
currently,I hope my craft's airspeed can achieve 130kph but current big airspeed only achieve no more than 80kph.
emm......hp mean,I don't know what are you referring?throttle servo input mean?
1638266237260.png
 
BrokeDad said:
In addition to the above advice

If you go into the .rfvehicle file for your custom model you can edit it. It's just a text file.
Look for:

TorquePercent=FLOAT:1.

You can edit the number above 4 (1=100, 2=200, etc) and save out the text file. This allows you to set the engine power over 400% which you are limited to in the built in editor.

You can also copy and edit a motor you currently have. Use Simulation - Manage User Files to create a copy and rename it.
Click to expand...
thanks,I will try to revise my text file according to your suggestion.
 
justin_wang said:
as the follow picture shows，the red line motor is working on my aircraft.
I am making a compound helicopter，when the main rotor's is closed,the rotor can be rotated by propeller which generates relative incoming flow,the rotation of rotor and fix wing can both produce lift.I am trying to determine relation between its velocity and stable RPM in rotation state.So,now,I don't know that how much is final speed needed.to achieve good result,I want to test its speed and stable RPM.
currently,I hope my craft's airspeed can achieve 130kph but current big airspeed only achieve no more than 80kph.
emm......hp mean,I don't know what are you referring?throttle servo input mean?
View attachment 127185
Click to expand...

HP (horsepower) is a unit for power like watts. Typically used for internal combustion engines.

I googled the motor and it seems to a fairly powerful motor. https://www.rcgroups.com/forums/showthread.php?280623-Kontronik-KBM-39-28-spec
 
justin_wang said:
just as you say，it is a fairly powerful motor. I check my param of engine，when I revise its gear ratio from 1 to 3，its power mean increases from 283W to 893w，its thrust increases from 25.51N to 55.45N.
Click to expand...

did that get you enough power or do you still need more?
 
legoman said:
did that get you enough power or do you still need more?
Click to expand...
maybe not enough，when I make the propeller's diameter,pitch and gear ratio increasing,thrust is improved,but the propeller is too big to touch the land.So this is a comprehensive engineering.
 
justin_wang said:
maybe not enough，when I make the propeller's diameter,pitch and gear ratio increasing,thrust is improved,but the propeller is too big to touch the land.So this is a comprehensive engineering.
Click to expand...

more blades, less diameter, more pitch. or a different motor that spins faster with smaller diameter.

more blades

varioPROP

www.ramoser.de

if you post an EA I can look at it and find a motor and make some suggestions
 
BrokeDad said:
You can change the Prop Visual Scale in the editor. It will effect if it hits the ground or not. Of course the visual scale will not change the physics of it. Often when I size up models I make the prop much larger visually. You can also make it smaller using less than 100%.
Click to expand...
nice，a good idea！I will try to do it.
 
legoman said:
more blades, less diameter, more pitch. or a different motor that spins faster with smaller diameter.

more blades

varioPROP

www.ramoser.de

if you post an EA I can look at it and find a motor and make some suggestions
Click to expand...
ok,please give me some suggestions,I need more aspects of suggestions,like flight control,CG location and so on. by the way, my flight control of side-by-side helicopter model referred to V22 model,but I don't seem to do well enough. In future,I will do SITL using ardupilot and RF9,so I want to build a suitable model for SITL.
 
I made these changes to model

removed the gyro's connections (to make sure some of the oscillations where not gyro induced)
adjusted so of the inputs so my brain could fly it
added some weight it seemed light. It also helps keep the rotors spooled at lower speeds
adjusted the rotor specs to the following (to make the rotor auto rotate) (I was also trying to find its instability)
also increase head stiffness and changed the rotor blades
2021-12-02 02_35_33-Window.jpg
reduce the prop diameter and pitch and adjusted the gear ratio. it is able to maintain about 900-1000 RPM at the rotors at 40-50 MPH 66-80 KPH at a moderate throttle.

my thoughts:
the wing loading is light enough that the rotors are almost not necessary. the size wings with the rotor downwash may be hindering the airplane. I was able to take off with zero rotor speed at 30 mph 50 KPH.
 

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legoman said:
I made these changes to model

removed the gyro's connections (to make sure some of the oscillations where not gyro induced)
adjusted so of the inputs so my brain could fly it
added some weight it seemed light. It also helps keep the rotors spooled at lower speeds
adjusted the rotor specs to the following (to make the rotor auto rotate) (I was also trying to find its instability)
also increase head stiffness and changed the rotor blades
View attachment 127205
reduce the prop diameter and pitch and adjusted the gear ratio. it is able to maintain about 900-1000 RPM at the rotors at 40-50 MPH 66-80 KPH at a moderate throttle.

my thoughts:
the wing loading is light enough that the rotors are almost not necessary. the size wings with the rotor downwash may be hindering the airplane. I was able to take off with zero rotor speed at 30 mph 50 KPH.
Click to expand...
thanks for your hard work.the rotors are necessary because I want to make a compound helicopter model which has side-by-side helicopter mode and fixed wing mode with rotors autorotation.
currently,your revised model is very good and stable when I fly it. ok ,we can regard it as fixed wing mode,but its side-by-side helicopter mode will not come true.
so my thoughts:
adjust the rotors' servo input and other param,such as flap angle,cyclic pitch and collective pitch,ensure it to vertical takeoff and landing by side-by-side helicopter.the aim is that the helicopter mode and fixed wing mode can switch to each other in suitable speed envelope, like tlitrotor,but no tilt.
now I do not know whether my thought can come true in RF9. or is it possible to use ardupilot frame to control it and come true?we team will revise its simulation firmware to finish its SITL.
by the way,today,when I increase maximum flap angle from 1deg to 3deg,I find it is difficult to control its roll at high speed.I am not sure whether the flap angle is so big that cause the rotor to side backward. I am not sure whether is aerodynamic reason. the question maybe influence helicopter model. could you give me some suggestions?
 
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