Turboshaft Help!

[EmanonP]

Humbling experience so far.

I've built a simple test plane.    Turbo shaft engine, 2 blades, fuel, tail, elvons and wheels.    

I deploy the props, crank up the torque limit and head down the runway.    By adjusting the deploy angle, I can work up just enough speed to take off.

From there it goes down hill.   Airspeed drops quickly.   No amount of deploy angle/torque limit etc seems to allow me to maintain airspeed.   What am I missing?

I've tried adjusting authority limiter and brake on the turboshaft and no go.     Also, for some reason the B key (brakes) also kills the engine.     

I can figure out almost all aspects of space travel, but this is stumping me.    Hate being limited to the Weesley engine as I can't climb past 10K or so.   

Thanks in advance.

[AHHans]

15 hours ago, EmanonP said:

Turbo shaft engine, 2 blades, fuel, tail, elvons and wheels.

There's your problem, you are missing the wings! SCNR!

O.K., jokes aside. First the easy part:

15 hours ago, EmanonP said:

Also, for some reason the B key (brakes) also kills the engine.

Yes, that's intentional. If you don't want this, then you can remove the turboshaft engine from the "Brakes" action group.

Another issue is that if you only have one propeller, then you have to counteract the torque from that propeller with your controls. (I.e. ailerons, reaction wheels, or - if you are crazy enough - RCS thrusters.) Depending on your plane the severity can go from being a mild annoyance to making your plane unflyable.

15 hours ago, EmanonP said:

By adjusting the deploy angle, I can work up just enough speed to take off.

The way you phrase this sounds like you have problems getting up to speed, is that correct? Even the small turboshaft engine is ridiculously overpowered for a small plane, but it can be that you don't have enough propeller area to convert that power into thrust. For my small planes I use two of the largest propeller blades with a small electric motor. If you set the deploy angle to 90 (i.e. have the blades perpendicular to the air), which torque setting do you need to get the engine to max RPM?

Otherwise there isn't much I can say. It would help a lot if you would post the craft file of your plane.

[EmanonP]

Thanks for the info, but still no joy.    I only have 2 size props available at this time, the small version, and the helicopter version.   The latter won't fit.

One additional bit of info....I get no engine sounds either.    Still barely able to make it to take off speed, and as soon as I do lift off, airspeed drops instantly.

Not sure how to post the craft file, as I'm unable to open it myself.     Build is basically cockpit, liquid fuel (with only 10% fuel to save weight),  enough wing surface to give lift
and control surfaces.     Also the first turboshaft engine available through research.   

Need science points, but hard to do when they now are asking for elevations above 18K, which the Weesley won't handle.

Edited November 12, 2019 by EmanonP

[AHHans]

11 hours ago, EmanonP said:

I get no engine sounds either. 

Not implemented (yet?), see: Bug #23179

Did you do the test on how much engine torque you need, that I suggested? You can also try adding more propeller blades to the engine.

11 hours ago, EmanonP said:

Not sure how to post the craft file, as I'm unable to open it myself. 

To find it you need to find where your copy of KSP is installed, and in there in "saves/<YOUR_SAVEFILE_NAME>/Ships/SPH/<YOUR_CRAFT_NAME>.craft"

E.g. my test plane that I just did is in: "/data/SteamLibrary/steamapps/common/Kerbal Space Program/saves/sandbox/Ships/SPH/Prop Plane Turbo.craft"

Publish that file on a file-hosting service like Google-Drive, or Dropbox, or whatever, and post the link to that here.

Edited November 13, 2019 by AHHans
formatting

[Guest]

Try enabling the aerodynamics overlay (F12) then adjusting the deploy angle. You should see the force vectors change. If you can get rolling I'm betting that your problem is just finding the right blade pitch. The motor is way way way powerful and two blades should produce ample thrust at sea level.