[Stock Helicopters & Turboprops] Non DLC Will Always Be More Fun!

[Azimech]

6 minutes ago, EpicSpaceTroll139 said:

Just curious, what's the greatest payload anyone's gotten a with a practical helicopter? And propeller rotor efficiency?

Back in 1.0.4 my big coaxial helicopter was able to transport a 20t fuel tank. Propeller rotor efficiency ... could you explain your question please? Compared with what and what scale? They can't be compared with real life because propellers and rotors rotate much slower in KSP.

[EpicSpaceTroll139]

By rotor efficiency I mean: For every kN of thrust the blowers are exerting, how many kN of lift is the rotor providing?

On a different note, it turns out that the Thermohinge bearing is quite a bit stronger than anyone's given it credit for! I'll demonstrate when I get home

Edited June 2, 2016 by EpicSpaceTroll139

[Gman_builder]

56 minutes ago, Azimech said:

Back in 1.0.4 my big coaxial helicopter was able to transport a 20t fuel tank. Propeller rotor efficiency ... could you explain your question please? Compared with what and what scale? They can't be compared with real life because propellers and rotors rotate much slower in KSP.

By the way. On a propeller plane, as in piston or turboprop, the props spin at between 4k and 8k RPM. But a helicopter's rotor on average spin around 400 RPM which equates to about 40 RAD/s. So helicopter rotor blades in KSP actually spin at a closer speed to real life than turboprops do.

[Azimech]

30 minutes ago, EpicSpaceTroll139 said:

By rotor efficiency I mean: For every kN of thrust the blowers are exerting, how many kN of lift is the rotor providing?

On a different note, it turns out that the Thermohinge bearing is quite a bit stronger than anyone's given it credit for! I'll demonstrate when I get home

You can test it yourself using my test rig :-)

https://kerbalx.com/Azimech/77I-Propeller Thrust Tester 11

Might need an update though.

When I first built the rig, it seemed that my earliest engines/props had an efficiency of 8%. With a lot of development I was able to increase it to 28% just before 1.0 arrived. I had engines/props delivering 180 kN static thrust.

[Majorjim!]

Just now, EpicSpaceTroll139 said:

t turns out that the Thermohinge bearing is quite a bit stronger than anyone's given it credit for!

Damn right it is! You just have to build them properly and carefully!

[EpicSpaceTroll139]

I'm not going to specify the exact numbers yet, but Koro (an awesome dude who plays on the NoNameShips server) and I have discovered through much mucking around that the new aero can offer fantastic rotor efficiencies, at least for slow moving helicopters. I don't know about planes.

 

Ok I don't know what's up with Imgur (it won't finish uploading my pics, even after several attempts), but  -Resetting my internet fixed it- I've put together a tandem rotor helicopter which can carry a payload of about 50 tons, and its rotors get whopping 170% efficiency. Yes, that's right, it actually uses less fuel with the rotors than if I just pointed the same type of jet engines down. Each rotor uses 2 panthers blowing on a 3.75m fairing base as a turbine and has rotor blades made of the small rectangular wing parts set at 5 degrees pitch, all on Thermohinge bearing.

I'll post a download link soon, but currently I'm trying to work out some bugs, such as kraken attacks after performing the pinnacle maneuver on the VAB (don't ask me why this happens, but it seems reliably reproducible).

Edited June 2, 2016 by EpicSpaceTroll139

[Azimech]

That's amazing dude! Beautiful as well!

I'll update my rig soon and set a new benchmark. Rotors and propellers are a different thing, so when I have my new standard prop ready, I'd love to test your engines. How do the engines cope with high speeds (28+ rad/s)? The reason I ask is because there's a design limit and compromise with turboprops, above 28 rad/s you get a massive increase in turbine blade extension due to the Unity/KSP spaghetti joints.

Edited June 3, 2016 by Azimech

[EpicSpaceTroll139]

The bearings cope with the high rpm amazingly well. However, I had to modify the rotors from Koro's original design in order to cope with the expansion. When I first started trying to really test their abilities, they would eventually expand enough that the front rotor would clip its blades on the engine for the rear rotor. Interestingly enough, this did not usually result in a crash. When the front rotor lost its outer segments, it got less drag, and thus sped up until it had expanded enough to almost fill the space of the original blade, and got almost as much lift as before. While this was kind of cool, it didn't look great, and didn't seem very safe, so one of the modifications I did was overlap the blade segments a bit, so as they expand, they become what the old original length was.

[Bloojay]

How are you with small scale and/or Rocket power?

[Bloojay]

propellers i mean

[EpicSpaceTroll139]

10 minutes ago, Bloojay said:

10 minutes ago, Bloojay said:

How are you with small scale and/or Rocket power?

Ok seemed to have messed this quote box up and mobile won't let me fix, delete, or type outside of it

Oh wait now it... idk...

Anyways, I'll probably work on more efficient small helps. By rocket power are you just meaning a heli that can work without oxygen, or is there another specific reason for rockets?

 

[Bloojay]

sorry about the duel post I was expecting them to merge

anyway by rocket power i mean propellers with there own fuel supply that use rockets to spin, like that one (iconic?) design from a really long time ago, thinking about it now they are probably the inferior design by a long shot, no real reason to it, just curious 

[EpicSpaceTroll139]

Ah you mean rotors with tip jets! If there were a way to throttle such jets while controlling the main craft I would totally do this.

[Bloojay]

... add a probe core

[Azimech]

2 hours ago, Bloojay said:

sorry about the duel post I was expecting them to merge

anyway by rocket power i mean propellers with there own fuel supply that use rockets to spin, like that one (iconic?) design from a really long time ago, thinking about it now they are probably the inferior design by a long shot, no real reason to it, just curious 

Yes the earliest helicopters and propeller airplanes in KSP worked with this principle. I didn't like it, that's why I invented the stock turboshaft.

[Bloojay]

4 minutes ago, Azimech said:

Yes the earliest helicopters and propeller airplanes in KSP worked with this principle. I didn't like it, that's why I invented the stock turboshaft.

whats the smallest turbo you've made?

[Majorjim!]

2 hours ago, Bloojay said:

whats the smallest turbo you've made?

This is the smallest 'turbo prop' made yet, made by @EpicSpaceTroll139 Using the smallest possible hinge in KSP, the thermo hinge invented by me.

 

[EpicSpaceTroll139]

5 hours ago, Bloojay said:

... add a probe core

The rotors already have these actually in order to prevent the DMP server I test these on from autodeleting them. What I'm getting at is that you wouldn't be able to throttle while controlling the main craft. In other words, whenever the throttle needed to be changed, one would have to switch to the rotor, change the throttle, then switch back to the main craft. This would not only be annoying, but also make hovering and maneuvering much harder. Also it would probably be a death sentence in DMP because whenever you switch ships there, it's liable to switch you to someone's plane 20km away and not let you go back.

[Azimech]

2 hours ago, Bloojay said:

whats the smallest turbo you've made?

Can't decide on the airplanes.

https://kerbalx.com/Azimech/77I-UAV1

https://kerbalx.com/Azimech/77I-Azi2 Whistling Gnome

https://kerbalx.com/Azimech/77I-Azi3 Whistling Goblin

Smallest helicopter:

https://kerbalx.com/Azimech/77I-3H1

And today, this might interest @EpicSpaceTroll139, I've adapted your coaxial helicopter engine to build a turboprop out of it. Hope you don't mind :-)

 

 

26 minutes ago, EpicSpaceTroll139 said:

The rotors already have these actually in order to prevent the DMP server I test these on from autodeleting them. What I'm getting at is that you wouldn't be able to throttle while controlling the main craft. In other words, whenever the throttle needed to be changed, one would have to switch to the rotor, change the throttle, then switch back to the main craft. This would not only be annoying, but also make hovering and maneuvering much harder. Also it would probably be a death sentence in DMP because whenever you switch ships there, it's liable to switch you to someone's plane 20km away and not let you go back.

This will be a problem for adjusting propeller pitch ... back to fixed pitch propeller for multiplayer then.

[Majorjim!]

Just now, Azimech said:

I've adapted your coaxial helicopter engine to build a turboprop out of it.

His is a coaxial turbo prop is it not?

[Azimech]

1 minute ago, Majorjim said:

His is a coaxial turbo prop is it not?

Correct. Had to change quite a lot though. Changed amount of turbine blades from 4 to 8 per shaft & increase diameter and 4 times as many blowers. Turboprops are a lot more demanding than turboshafts (helicopters).

[Azimech]

Don't have the time to finish today but I think this is a nice project. Think I'll totally rebuild the bearing though, it's got some problems with the increased torque and high RPM at the moment.

Thanks to @Majorjim and @EpicSpaceTroll139 this is a revolution in stock turboshaft technology! But I don't think it will be able to break speed records, it's a little to fragile for high RPM. Classic engines can theoretically scale up to 50 rad/s (at that speed PhysX goes gaga), the low crash tolerance of the thermometer & antenna parts might be a problem.

Edited June 3, 2016 by Azimech

[EpicSpaceTroll139]

Ah yes, I never really optimized that thing. I was just like "hey it flies!" And shared it

@Azimech How dare you make a plane with my engine!  Just kidding, that's awesome that you were able to make a plane with that!

 

Edited June 3, 2016 by EpicSpaceTroll139

[Majorjim!]

Just now, Azimech said:

Thanks to @Majorjim and @EpicSpaceTroll139 this is a revolution in stock turboshaft technology!

Cheers dude, and kudos to @EpicSpaceTroll139 !

 I would like to make some of these types of craft and I will start after my constellation pack is complete.

[selfish_meme]

55 minutes ago, Azimech said:

Don't have the time to finish today but I think this is a nice project. Think I'll totally rebuild the bearing though, it's got some problems with the increased torque and high RPM at the moment.

Thanks to @Majorjim and @EpicSpaceTroll139 this is a revolution in stock turboshaft technology! But I don't think it will be able to break speed records, it's a little to fragile for high RPM. Classic engines can theoretically scale up to 50 rad/s (at that speed PhysX goes gaga), the low crash tolerance of the thermometer & antenna parts might be a problem.

Why contrarotate each prop, probably simpler and lighter for each engine to rotate opposite to cancel out torque