Props and Rotors

[PearGrylls909]

Having not played with robotic parts and creating lift aircraft that way maybe I am a bit behind but some explanation how these new parts are intended to work would be very helpful. Currently there is nothing, not so long ago there was always a live stream or the version was released to people who stream so they can show it off. I cant seem to make anything that creates thrust of lift, on a modded or unmodded save. 

The omission of any sound files for these parts is also kind of disappointing. They are cool but the fact that this game has always lacked proper sounds cheapens the experience a bit. I feel like that should be something that is focused on in the future given that its been 6-7 years and we have never seen a comprehensive sound overhaul. 

[Wjolcz]

1.Make sure the rotors spin the way the propellers' leading edges (grey stripes) cut the air (not sure what to actually call that action lol).

2.If you can't be bothered with adjusting prop pitch just deploy them and set the authority slider to 45 (they should cut the air at roughly 45° angle). Seems to work best for lazy people like me.

3.Set the rotor's Torque(%) to 'Main throttle' in action groups.

4. Adjust throttle gradually during take-off.

5. Try not to crash.

However, consider experimenting with prop pitch a bit. I got to over 160m/s (and over 200m/s in a dive) at half the throttle by adjusting the propellers during flight. Didn't happen with them being locked at 45° even at full throttle (same rotor+propeller setup).

Edited July 11, 2019 by Wjolcz

[Bill Phil]

Yeah I'm very confused as well. I can get it spinning but it doesn't produce any thrust. I don't know what to do to make it work.

Just now, Wjolcz said:

1.Make sure the rotors spin the way the propellers' leading edges (grey stripes) cut the air (not sure what to actually call that action lol).

2.If you can't be bothered with adjusting prop pitch just deploy them and set the authority slider to 45 (they should cut the air at roughly 45° angle). Seems to work best for lazy people like me.

3.Set the rotor's Torque(%) to 'Main throttle' in action groups.

4. Adjust throttle gradually.

5. Try not to crash.

However, consider experimenting with prop pitch a bit. I got to over 160m/s (and over 200m/s in a dive) at half the throttle by adjusting the propellers during flight. Didn't happen with them being locked at 45° even at full throttle (same rotor+propeller setup).

Hmm.

I'll try that later.

[Wjolcz]

2 minutes ago, Bill Phil said:

Yeah I'm very confused as well. I can get it spinning but it doesn't produce any thrust. I don't know what to do to make it work.

It's because the props are in 'neutral' positon when placed. They don't push air in any direction.

[Bill Phil]

1 minute ago, Wjolcz said:

It's because the props are in 'neutral' positon when placed. They don't push air in any direction.

Yeah I thought it was something like that. Didn't know how to change the angle though.

Edited July 11, 2019 by Bill Phil

[Bill Phil]

26 minutes ago, Wjolcz said:

It's because the props are in 'neutral' positon when placed. They don't push air in any direction.

I got something to fly so that’s cool.

[aeroeng14]

Yeah I'm having problems myself with the props. What size do you need to make a small mark 1 plane? I went all the way up to the largest propeller and torque setting and still couldn't get any thrust out of it. I tried deploying and undeploying the propeller, changing the actuation, and keybinding to either the pitch control or the torque. Yes I did make sure the props were spinning/mounted the right way (CW or CCW). I was able to get a rotor setup to work, but not configured correctly with the new action group axes. 

[The Destroyer]

I've been able to make them work, but "authority limiter" seems to do nothing. If the blade is deployed, it will produce lift in one direction. If it is inverted, it will produce it in another. Set it to -150 or 150 though, no change in actual lift.

[Geschosskopf]

4 hours ago, Wjolcz said:

2.If you can't be bothered with adjusting prop pitch just deploy them and set the authority slider to 45 (they should cut the air at roughly 45° angle). Seems to work best for lazy people like me.

Actually, it's pretty easy to make manually variable-pitch props by putting the "authority limiter" of the blades on a KAL.  NEVER run the KAL animation, just open the editor in flight and manually move the timeline.  To do this, understand that 100 authority = 60^ of blade motion from the starting position and 150 (max) = 90^ movement.  Which can be both positive and negative.  25^ (= 42 authority) is the ideal takeoff setting but you can increase pitch to about 60^ at cruise.  And you can also do this to have reverse thrust position on the timeline.

Edited July 12, 2019 by Geschosskopf

[fourfa]

Here's the setup that seems most logical to me:

1. Motor RPM limit(s) on 'Main Throttle' group (you won't use this often, just for trimming speed for landing basically)
2. Toggle Motor Power, and Toggle Deploy on all props on 'Stage' group
3. Prop Authority Limit on Translate F/B, and manually set Authority Limiter on all props to 0 in SPH.

Launch, set throttle to max, space bar to stage.  Engines spin to max RPM but props have no bite - they're feathered.  Use Translate (H/N by default) to engage props and speed up for takeoff. 

Optimum blade pitch is variable with speed.  Pin out your prop part action window.  Taking off from 0m/s, set authority limit to ~100.  Once you're flying, try reducing the limit.  I've found max speed between ~70-95 depending on the craft (F12 for aero force visualizer, and try to get the longest forward lines).  Greater than 100 usually seems slower. 

One nice aspect of this setup - just hit space again to feather the prop and shut down the motor for minimum drag.  Based on how thirsty the new LF motors seem to be, you'll need this feature a lot   New props with old electric motors & fuel cells is much less thirsty, and seems just as fast as the Mk1 LF motors (easy 200m/s+ for a Mk1 plane with twin 0.625m electric props).

Physics timewarp with new props is just as bad as elevons so far.

EDIT: tossed up an example on kerbalx https://kerbalx.com/fourfa/Kessna-Twin-MkII

Edited July 12, 2019 by fourfa
added craft

[Bill Phil]

1 hour ago, The Destroyer said:

I've been able to make them work, but "authority limiter" seems to do nothing. If the blade is deployed, it will produce lift in one direction. If it is inverted, it will produce it in another. Set it to -150 or 150 though, no change in actual lift.

I think you have to actually deploy the props in general and authority limiter doesn’t matter.

Edited July 12, 2019 by Bill Phil

[The Destroyer]

44 minutes ago, Bill Phil said:

I think you have to actually deploy the props in general and authority limiter doesn’t matter.

Yeah, but it should. If having them deployed and changing the limiter actually changed how much lift it generated based on the pitch, then I would have a proper collective. Other users report it to work this way (including fourfa just above it seems), but something seems broke with mine.

[Bill Phil]

3 minutes ago, The Destroyer said:

Yeah, but it should. If having them deployed and changing the limiter actually changed how much lift it generated based on the pitch, then I would have a proper collective. Other users report it to work this way (including fourfa just above it seems), but something seems broke with mine.

I've noticed strange behavior related to the orientation of the props compared to the direction of rotation. I built a kind of P-38 plane with the idea of having the two sets of props counter rotate, so I set them up opposite each other. But when trying to fly I had to make the two sets of props rotate in the same direction to get net thrust, even though the props were set up so that they would generate lift while rotating in opposite directions. 

I did notice the model changing based on the authority limiter, but I don't think it really affected the thrust.

[The Destroyer]

11 hours ago, Bill Phil said:

I've noticed strange behavior related to the orientation of the props compared to the direction of rotation. I built a kind of P-38 plane with the idea of having the two sets of props counter rotate, so I set them up opposite each other. But when trying to fly I had to make the two sets of props rotate in the same direction to get net thrust, even though the props were set up so that they would generate lift while rotating in opposite directions. 

I did notice the model changing based on the authority limiter, but I don't think it really affected the thrust.

When I did that setup as well, I found the same thing. What I had to do was set the "deploy" direction of the other prop to inverted, then it worked properly. As far as I can tell, prop direction, clockwise/counter model, authority limiter, all doesn't matter. Only if its deployed, and if its inverted.

[Bill Phil]

3 hours ago, The Destroyer said:

When I did that setup as well, I found the same thing. What I had to do was set the "deploy" direction of the other prop to inverted, then it worked properly. As far as I can tell, prop direction, clockwise/counter model, authority limiter, all doesn't matter. Only if its deployed, and if its inverted.

I’ve found that prop authority limiter affects performance in flight. Mostly max speed.

Got to 247 m/s in level flight pretty easily in a plane that used to max out at about 115, just by adjusting the authority limiter. I’m using the track editor to adjust it for all props at the same time.

Edited July 12, 2019 by Bill Phil

[jpkerman]

Does anybody think it is a little humorous that the hardest task in a game about rocket building has become how to make a propeller engine?

[Goody1981]

50 minutes ago, jpkerman said:

Does anybody think it is a little humorous that the hardest task in a game about rocket building has become how to make a propeller engine?

KSP - Kerbal Supermarine Program

[Pds314]

3 hours ago, jpkerman said:

Does anybody think it is a little humorous that the hardest task in a game about rocket building has become how to make a propeller engine?

Nah. It used to be hard. Back when we were making landing gear-supported, blower-driven turbo props 4 meters across with anemic amounts of power and ungodly fuel consumption.

Nowadays it's much easier. Literally just plop down some prop blades on a very small rotor and you have a 1300 hp engine that can do 180 m/s with ease and will never over-rev, will never escape its housing, can run for a ridiculously long time, doesn't stretch out, is only a handful of parts, weighs practically nothing, is permanently attached, and won't fail mechanically.

You don't know how easy you have it.

Edited July 13, 2019 by Pds314

[Pds314]

@Azimech can explain more how props were back then. Both before and after the 1.0 update atmosphere changes.

[Azimech]

16 hours ago, jpkerman said:

Does anybody think it is a little humorous that the hardest task in a game about rocket building has become how to make a propeller engine?

Ya think?
 

 

[Azimech]

Forgot about this image. Four years ago. Eight blowers, sixteen turbine blades. Top speed: 57 m/s.


 

[Pixel of Life]

There's definitely something wrong with the propeller blades. "Deploy"ing them and adjusting the authority limiter has zero effect on the amount of lift and drag they generate. Also, toggling the deploy direction kills the lift and makes them generate massive amounts of drag even if the authority limiter is at 0 (so the pitch angle of the blades shouldn't change when extending/retracting them).

[Loghogan]

I don't think so because I've build 4 different copters in the last couple days. All of them operate on authority limiters alone and they fly like a dream.

 

[Azimech]

3 hours ago, Pixel of Life said:

There's definitely something wrong with the propeller blades. "Deploy"ing them and adjusting the authority limiter has zero effect on the amount of lift and drag they generate. Also, toggling the deploy direction kills the lift and makes them generate massive amounts of drag even if the authority limiter is at 0 (so the pitch angle of the blades shouldn't change when extending/retracting them).

Tiny increments, observe.

[Pixel of Life]

1 hour ago, Azimech said:

Tiny increments, observe.

Nevermind, it appears to be a problem with AtmosphereAutopilot. I removed the mod and the prop blades are now working correctly.