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

[Azimech]

4 hours ago, Matuchkin said:

I'm thinking, if we spin a turboprop with an engine that is spinned by another engine that is spinned by another engine, etc, we can really speed up rotors while ensuring that each part doesn't blow up against another.

Ah ... no. There are two KSP limitations that prohibit this.

The first is the centrifugal positional expansion of parts ... something I think you already hinted at.
The second is the hard limit of 51 rad/s angular velocity. We're not sure what's the cause, I hope Squad will solve this one day. It's the biggest wall to creating small, efficient turboprops at real sizes.

[The_Rocketeer]

@Azimech how fast is your Chakora since 1.2? Are you still keeping up the turboprop speed challenge?

[Azimech]

2 minutes ago, The_Rocketeer said:

@Azimech how fast is your Chakora since 1.2? Are you still keeping up the turboprop speed challenge?

It's max speed is 7m/s lower in modified aero. Currently I'm more busy with my race track.

[The_Rocketeer]

8 minutes ago, Azimech said:

It's max speed is 7m/s lower in modified aero. Currently I'm more busy with my race track.

I confess I forget what it was before. Little help?

[Azimech]

2 minutes ago, The_Rocketeer said:

I confess I forget what it was before. Little help?

Ah yes ... okay this speed was recorded with modified aero.
https://kerbalx.com/Azimech/77I-Azi12-Curious-Chakora-v31

[The_Rocketeer]

@Azimech I built a puller-pusher plane using my B17 engines. It's fast, but I don't know quite how fast. I was going to post a screenshot once it had stopped accelerating, but KSP CTD and I don't have time to go again now. Also I'm still cheating using infinite fuel - a design drawback of that engine is it's not friendly for routeing fuel to the blowers - I am working on a new version that should be more convenient, as well as being lighter and more streamlined. Watch this space.

Regarding your race track, it caught my attention when it was first posted, but sadly/happily I don't have time for all the things I'd like to being doing on KSP at the moment, so I'll stick with the props for now

[The Optimist]

Turboprops are actually pretty fun to make. This testbed plane uses 64 juno pushers inside a hybrid bearing design. 

I wonder if a hybrid turboprop-electric engine would work. Electric engines push the plane to a high altitude, then the windmill jets give it more speed.

[life_on_venus]

15 hours ago, The_Rocketeer said:

Yah, I get what you mean. That's why I said what I said.

1. Imagine a windmill - this is your propellor shaft. The vanes (blades) turn when the wind blows them around.
2. Now imagine the wind is created not by nature but by a jet engine. Still good, right?
3. Now imagine the jet is several jets attached to the vanes of another windmill. The windmill they're attached to will turn in the opposite direction than the one that they're trying to blow. So now you have two windmills that turn more slowly than the one you had before.
4. So to fix this, you add another windmill, with more jet engines, to blow the middle windmill around in the right direction. You think this will mean the propellor windmill will turn even faster than before. What actually happens is your new windmill turns one way, the middle windmill stays still, and the propellor windmill turns as slowly as it did before.
5. You could add as many windmills as you want and this would still happen.
6. You situation is slightly different, because it's a windmill inside a windmill, inside a windmill, so the outside windmills have higher leverage than the inner ones, but each windmill still has friction losses to cope with and the forces are still pretty close to balanced. So, the inside windmill - the turboshaft - turns slower than it would if it was just one really big windmill inside a bunch of static blowers.

I... What? Could you post pictures so a pleb like me can understand? 

I've slowed down with this stuff ebcause of schoolwork (and regular work!) but I've advanced the car I was working on a teeny bit. Still not got a working transmission. I tried to make 2 fixed gear ratios with their own clutches, but the clutches didn't work 

[Azimech]

1 hour ago, The Optimist said:

Turboprops are actually pretty fun to make. This testbed plane uses 64 juno pushers inside a hybrid bearing design. 

I wonder if a hybrid turboprop-electric engine would work. Electric engines push the plane to a high altitude, then the windmill jets give it more speed.

 

Unfortunately, no. Since the blowers are just Juno jet engines, blower output decreases with altitude. Top speed usually remains pretty steady until 6000m, then it starts to drop off.

And what are these strange words suddenly ... windmill ... pushers ... It's just turbines and blowers, guys ;-)

[The Optimist]

1 hour ago, Azimech said:

 

Unfortunately, no. Since the blowers are just Juno jet engines, blower output decreases with altitude. Top speed usually remains pretty steady until 6000m, then it starts to drop off.

And what are these strange words suddenly ... windmill ... pushers ... It's just turbines and blowers, guys ;-)

I refuse to call them what they're supposed to be called.

[Azimech]

Fascinating.

[The_Rocketeer]

@Azimech what is a turbine if not a multitude of windmills... in a tube? Ah, shut it. I'm not debating semantics with you cretins

@life_on_venus I'm afraid I'm a words and imagination guy, not a pictures guy. If you don't want to take my word for it, you're welcome to try it out and see what happens.

[The Optimist]

1 hour ago, The_Rocketeer said:

@Azimech what is a turbine if not a multitude of windmills... in a tube? Ah, shut it. I'm not debating semantics with you cretins

@life_on_venus I'm afraid I'm a words and imagination guy, not a pictures guy. If you don't want to take my word for it, you're welcome to try it out and see what happens.

Woah,that's a bit uncalled for...

[The_Rocketeer]

@The Optimist it's a joke.

[life_on_venus]

5 hours ago, The_Rocketeer said:

@Azimech what is a turbine if not a multitude of windmills... in a tube? Ah, shut it. I'm not debating semantics with you cretins

@life_on_venus I'm afraid I'm a words and imagination guy, not a pictures guy. If you don't want to take my word for it, you're welcome to try it out and see what happens.

I do wanna take your word for it, but I can't for the life of me picture what "it" is! 

[Heckspress]

2 hours ago, life_on_venus said:

I do wanna take your word for it, but I can't for the life of me picture what "it" is! 

 

7 hours ago, The_Rocketeer said:

@The Optimist it's a joke.

methinks @The_Rocketeer is misconstruing what the Optimist is trying to get across. The windmills are layered, except they're all pushing each other in the same direction. Imagine concentric windmills, the outermost ring pushes the next inward ring ccw, then that ring pushes the one inside of that one ccw ALSO, so they begin compounding speed

 

[life_on_venus]

5 hours ago, Heckspress said:

 

methinks @The_Rocketeer is misconstruing what the Optimist is trying to get across. The windmills are layered, except they're all pushing each other in the same direction. Imagine concentric windmills, the outermost ring pushes the next inward ring ccw, then that ring pushes the one inside of that one ccw ALSO, so they begin compounding speed

 

Oh okay. That's gonna need some mighty strong bearings! (I think this could work well in KSP though)

[Azimech]

 

This is the Azi-19 Jolly Jinn. My first turboprop that needs active cooling Something I don't mind at all ... I wish all engines needed it.

Engine is a wheelless, the hollow turbine shaft rotates around a stack of MK0 fuel tanks. Eight AFSV's as turbine blades because they magically don't expand from the shaft like the other parts do ... but they heat up quickly. The engine doesn't like high revs and starts to vibrate violently above 35rad/s so prop pitch needs adjustment but not often: due to changes in the atmospheric model, this plane can accelerate with the engine running only 18rad/s! Only 6 blowers, 130 parts, 12t. 

Take off speed: 30m/s. With adjusted drag it's top speed is 135m/s at sea level, with the engine running only 27.6rad/s.

[The_Rocketeer]

4 hours ago, Azimech said:

 

This is the Azi-19 Jolly Jinn. My first turboprop that needs active cooling Something I don't mind at all ... I wish all engines needed it.

Engine is a wheelless, the hollow turbine shaft rotates around a stack of MK0 fuel tanks. Eight AFSV's as turbine blades because they magically don't expand from the shaft like the other parts do ... but they heat up quickly. The engine doesn't like high revs and starts to vibrate violently above 35rad/s so prop pitch needs adjustment but not often: due to changes in the atmospheric model, this plane can accelerate with the engine running only 18rad/s! Only 6 blowers, 130 parts, 12t. 

Take off speed: 30m/s. With adjusted drag it's top speed is 135m/s at sea level, with the engine running only 27.6rad/s.

OK, I'm impressed. Download link?

I've been working on an engine that uses radiators as turbine blades - they're actually ideal for this since (AFAIK) they have the highest max temperature of any part and can even be switched to shed excess heat.

Interesting also that your design process and mine are parallel but conforming to totally different standards - I am trying to keep everything small, so my engines are not very torque-y, have to rev pretty fast, and having little space to work in means I'm often trying to slay gremlins or recalibrate things.

[The_Rocketeer]

11 hours ago, Heckspress said:

 

methinks @The_Rocketeer is misconstruing what the Optimist is trying to get across. The windmills are layered, except they're all pushing each other in the same direction. Imagine concentric windmills, the outermost ring pushes the next inward ring ccw, then that ring pushes the one inside of that one ccw ALSO, so they begin compounding speed

 

Erm. Unless I've completely missed the point, I'm pretty sure I'm clear on what's being suggested - that should be obvious from the later steps in my explanation.

So, each rotor has blades (which are blown by the next rotor out) and engines (which blow the next rotor in). So taking a rotor near the middle, it is sped up by the next rotor out, and in turn is supposed to speed up the next rotor in. Except, and here's the big issue, it's own engines will slow it down. And this will happen on every single step between rotors. Hence losses, hence a waste of time.

Also as Azimech observed, you can't compound angular velocity in this way in KSP simply because there is a hard speed-limit built into the game for part rotation.

[Azimech]

1 hour ago, The_Rocketeer said:

OK, I'm impressed. Download link?

I've been working on an engine that uses radiators as turbine blades - they're actually ideal for this since (AFAIK) they have the highest max temperature of any part and can even be switched to shed excess heat.

Interesting also that your design process and mine are parallel but conforming to totally different standards - I am trying to keep everything small, so my engines are not very torque-y, have to rev pretty fast, and having little space to work in means I'm often trying to slay gremlins or recalibrate things.

 

Here's the link: https://kerbalx.com/Azimech/77I--Azi19-Jolly-Jinn

Radiators as turbine blades ... I tried that before but fried them every time. Maybe now they have to be activated and draw electricity, the system can be fooled.

Autually while Azi19 looks pretty fat, underneath it's very light and compact. Take away the fairing and radiator panels and you have a flying stick. And not a single strut.

[The_Rocketeer]

2 hours ago, Azimech said:

Radiators as turbine blades ... I tried that before but fried them every time. Maybe now they have to be activated and draw electricity, the system can be fooled.

I'm using them without any overheating issues, tho they are still susceptible to centripetal drift and their collision box seems a big odd - perhaps yours were clipping the housing or something. As with my other engines I'm setting mine up as double-acting parts so they don't drift.

[lgsolaris]

Is there a tutorial on how to make these turbo props? I cant seem to figure it out. I can make decent "Electric" ( SAS Powered ) prop engines,but that's about it

[Majorjim!]

7 hours ago, lgsolaris said:

Is there a tutorial on how to make these turbo props? I cant seem to figure it out. I can make decent "Electric" ( SAS Powered ) prop engines,but that's about it

Then you are most of the way there. Once you know how to make bearings in KSP the rest is just trail an error. Download one of @Azimechs craft as he has spent the most time on them. You have to have jets blowing onto parts around the bearing to spin it around. After that you can refine the design to get more speed out of it. It's a nice easy, relaxing project as all the testing is done on the landing strip with only a few things that can go wrong, look how many people have managed it! You can do it too, just don't give up!

[lgsolaris]

Well, I finally decided to go and try to build a turbo prop by experimenting. Looked at some designs and copied some, but for whatever reason I cant make them have enough power to actually lift anything off the ground.

Fastest I've gotten with them was about 80 m/s, and even that fast my plane could not lift off the ground. That was even with the global drag multiplier at its lowest.