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

[Gman_builder]

Just now, Pds314 said:

It's not the crash tolerance. Nothing is crashing into anything at any significant velocity difference. The problem is wobble caused by it being composed of a dozen separate craft causing a self-sustaining wobble in the swashplate.

That's why I said don't quote me on that

[Azimech]

4 minutes ago, Pds314 said:

It's not the crash tolerance. Nothing is crashing into anything at any significant velocity difference. The problem is wobble caused by it being composed of a dozen separate craft causing a self-sustaining wobble in the swashplate.

Feels like a dead end then. Maybe you guys can do something with my experiment?

This is unmodified from 0.90 so it looks a little bit distorted. Don't have the time to correct it right now, gotta go to work.

https://www.dropbox.com/s/6ef7r3u25xnepig/cyclic-collective 0_25.craft?dl=0

 

It's supposed to look like this:

[Pds314]

13 minutes ago, Azimech said:

Feels like a dead end then. Maybe you guys can do something with my experiment?

This is unmodified from 0.90 so it looks a little bit distorted. Don't have the time to correct it right now, gotta go to work.

https://www.dropbox.com/s/6ef7r3u25xnepig/cyclic-collective 0_25.craft?dl=0

 

It's supposed to look like this:

Could it actually generate significant thrust? On a related note, I've found that the swashplate wobble was partially fixable, such that it can at least go somewhat faster now. Still, could be impractical to get anything off the ground with, as the best lift I've yet seen is about 5 tonnes between 4 blades.

Edited July 26, 2016 by Pds314

[Gman_builder]

21 minutes ago, Pds314 said:

Could it actually generate significant thrust? On a related note, I've found that the swashplate wobble was partially fixable, such that it can at least go somewhat faster now. Still, could be impractical to get anything off the ground with, as the best lift I've yet seen is about 5 tonnes between 4 blades.

well you better make a 5 ton heli then.

[Pds314]

9 minutes ago, Gman_builder said:

well you better make a 5 ton heli then.

A 5 tonne heli with 7+ tonne engine. Funny how that works.

Most rugged version I've built thus far. Still fails well before liftoff.

Hmm... With all my new-found understanding of multi-craft creations, maybe I'll make an ornithopter or something.

I tested earlier and, under the right circumstances, little linear actuators can lift some pretty heavy loads. I made a device to lift an 18-tonne fuel tank over and over without issue, using control surfaces.

Edited July 26, 2016 by Pds314

[Gman_builder]

9 hours ago, Pds314 said:

A 5 tonne heli with 7+ tonne engine. Funny how that works.

Most rugged version I've built thus far. Still fails well before liftoff.

Hmm... With all my new-found understanding of multi-craft creations, maybe I'll make an ornithopter or something.

I tested earlier and, under the right circumstances, little linear actuators can lift some pretty heavy loads. I made a device to lift an 18-tonne fuel tank over and over without issue, using control surfaces.

Do control surfaces have a weight limit? If not, we can theoretically actuate anything using them. With no torque required. The best part is that it is a single part.

[Pds314]

21 minutes ago, Gman_builder said:

Do control surfaces have a weight limit? If not, we can theoretically actuate anything using them. With no torque required. The best part is that it is a single part.

If they have a weight limit, I haven't found it. I guess I could pit two control surfaces vs. eachother and see if the universe explodes.

[Gman_builder]

37 minutes ago, Pds314 said:

If they have a weight limit, I haven't found it. I guess I could pit two control surfaces vs. eachother and see if the universe explodes.

Lol that's a good idea. I would pay to see that. Record it please and post it XD

[Rune]

On 25/7/2016 at 8:16 PM, Gman_builder said:

@EpicSpaceTroll139Over the past few weeks we have determined that it is all but impossible to run a prop over 51 rad/s Due to expansion and drag and whatnot. so that's pretty much the engine RPM limit unless we can engineer some kind of new prop that doesn't abide by the laws of KSP physics.

Funnily enough, that is much higher than RL helicopters. Those spin their rotors at a constant 300RPM or so, or ~31rad/s. The trick is to manage the rotor size (area), and controlling its lift dynamically through the swashplate.

Now, the swashplate is kind of important, but with enough magical reaction wheels, a lot of things can be done. And with mere floppy connections you could, in theory, take care of the absolutely-fundamental flapping and drag hinges. De la Cierva's first models only flew because they were made out of bamboo, and thus were very flexible, and then he got the inspiration for the fully articulated rotor that allows every modern helicopter to fly.

 

Rune. And the direction for the future are actually flexible rotors that make do without the articulations because 'awesome materials science'.

[Pds314]

39 minutes ago, Rune said:

Funnily enough, that is much higher than RL helicopters. Those spin their rotors at a constant 300RPM or so, or ~31rad/s. The trick is to manage the rotor size (area), and controlling its lift dynamically through the swashplate.

Now, the swashplate is kind of important, but with enough magical reaction wheels, a lot of things can be done. And with mere floppy connections you could, in theory, take care of the absolutely-fundamental flapping and drag hinges. De la Cierva's first models only flew because they were made out of bamboo, and thus were very flexible, and then he got the inspiration for the fully articulated rotor that allows every modern helicopter to fly.

 

Rune. And the direction for the future are actually flexible rotors that make do without the articulations because 'awesome materials science'.

The difference is that RPM in real life is not so strongly tied to efficiency. In a real helicopter, it's not unlikely that 25% of the energy of the fuel is reaching the rotor. In our helicopters, 31 rads/s is very bad for fuel efficiency. Effectively, from an engine with a torque radius of 0.5 meters and a speed of 31 rads/s, only 310 kW are transferred to the rotor per engine, with about 0.3 kg of fuel being burned at the same time. This puts the useful energy content of fuel at something like 1 Megajoule per kg of fuel vs. about 11. That is, real helicopters have engine that are 11 times more fuel efficient at the same RPM, this despite the Juno being unrealistically efficient. IRL, the Juno would consume twice as much fuel, as would the Panther, Whiplash and RAPIER and the bypass jet engines would have about half as much thrust.

Regarding the awesomepower of materials science. That might actually be possible to replicate in KSP.

As for reaction wheels, the big problem is that no amount of reaction wheels can fix assymetric torque. Basically, the problem is that you go too fast, gaining asymmetric lift, which rips the engine apart.

Edited July 26, 2016 by Pds314

[Azimech]

41 minutes ago, Rune said:

Funnily enough, that is much higher than RL helicopters. Those spin their rotors at a constant 300RPM or so, or ~31rad/s.

It really depends on blade count, blade length, vehicle mass, installed engine and gearbox. I've seen tacho's with ideal rotor RPM anywhere between 200 and 500.

Not to mention aircraft propellers (add 1000 - 2000).

51 minutes ago, Rune said:

Rune. And the direction for the future are actually flexible rotors that make do without the articulations because 'awesome materials science'.

I like the idea.

[Pds314]

It really depends on blade count, blade length, vehicle mass, installed engine and gearbox. I've seen tacho's with ideal rotor RPM anywhere between 200 and 500.

Not to mention aircraft propellers (add 1000 - 2000).

Well, especially light prop aircraft can get much higher. 3000 RPM isn't unheard of.

[Azimech]

Just now, Pds314 said:

Well, especially light prop aircraft can get much higher. 3000 RPM isn't unheard of.

True ... true. Especially with fixed, small propellers it can be advantageous to have a prop & engine with a wide RPM range.

[Gman_builder]

54 minutes ago, Rune said:

Funnily enough, that is much higher than RL helicopters. Those spin their rotors at a constant 300RPM or so, or ~31rad/s. The trick is to manage the rotor size (area), and controlling its lift dynamically through the swashplate.

Now, the swashplate is kind of important, but with enough magical reaction wheels, a lot of things can be done. And with mere floppy connections you could, in theory, take care of the absolutely-fundamental flapping and drag hinges. De la Cierva's first models only flew because they were made out of bamboo, and thus were very flexible, and then he got the inspiration for the fully articulated rotor that allows every modern helicopter to fly.

 

Rune. And the direction for the future are actually flexible rotors that make do without the articulations because 'awesome materials science'.

Helicopter rotor RPM depends largely on the vehicle. But it is usually around 400 - 450 RPM. So 51 rad/s is accurate.

[Azimech]

21 minutes ago, Pds314 said:

As for reaction wheels, the big problem is that no amount of reaction wheels can fix assymetric torque. Basically, the problem is that you go too fast, gaining asymmetric lift, which rips the engine apart.

Even with coaxials.

[Pds314]

Just now, Azimech said:

True ... true. Especially with fixed, small propellers it can be advantageous to have a prop & engine with a wide RPM range.

And of course RC planes are a seperate issue entirely, with RPM of 50000 or so not being uncommon.

[Gman_builder]

Just now, Pds314 said:

And of course RC planes are a seperate issue entirely, with RPM of 50000 or so not being uncommon.

That's in centrifugal RC jet engines. I'm pretty sure a 50,000 RPM prop is impossible in any standard.

I dunno why but I can't post images on here anymore. It doesn't give me the option too.

http://imgur.com/a/f65Ty

That's a helicopter tachometer. You can see the optimal RPM is around 400.

[Azimech]

Guys ...  check this!

 

[SpannerMonkey(smce)]

22 minutes ago, Pds314 said:

And of course RC planes are a seperate issue entirely, with RPM of 50000 or so not being uncommon.

 

20 minutes ago, Gman_builder said:

That's in centrifugal RC jet engines. I'm pretty sure a 50,000 RPM prop is impossible in any standard.

I dunno why but I can't post images on here anymore. It doesn't give me the option too.

http://imgur.com/a/f65Ty

That's a helicopter tachometer. You can see the optimal RPM is around 400.

Hi while I've still not been able to build an engine that I'd be prepared to share, still too explodey ,

The above quotes venture into one of my playgrounds and Pds is correct, in reference in particular to Nitro engines, which use a mixture of nitromethane, methanol and fine synthetic oil to achieve ridiculously high rpms,  my  last 1/8th formula car  redlined  at an ear splitting 42000 rpm in unrestricted form ( needless to say it's live fast, die young, and leave a good looking paperweight) oblig wiki link 

Back on topic totally blown away by the performance increase you lot have achieved in recent weeks, and always an interesting read too. (bonus)

[Gman_builder]

41 minutes ago, SpannerMonkey(smce) said:

 

Hi while I've still not been able to build an engine that I'd be prepared to share, still too explodey ,

The above quotes venture into one of my playgrounds and Pds is correct, in reference in particular to Nitro engines, which use a mixture of nitromethane, methanol and fine synthetic oil to achieve ridiculously high rpms,  my  last 1/8th formula car  redlined  at an ear splitting 42000 rpm in unrestricted form ( needless to say it's live fast, die young, and leave a good looking paperweight) oblig wiki link 

Back on topic totally blown away by the performance increase you lot have achieved in recent weeks, and always an interesting read too. (bonus)

I am also well versed in the land of RC cars, planes, and helicopter. In that car your talking about, the engine is geared down significantly from that 42,000 to something that can be put on the ground. It's probably still fast AF but the wheel definitely don't spin at 42k RPM. I said it is impossible for a prop to spin at 50,000 RPM. Not the engine. Obviously props are much more directly linked to the engine than wheels. In the less complex planes, the prop is stuck right onto the motor's drive shaft.

On the other hand, the Wren 100D Centrifugal Gas turbine IDLES at 42,000 RPM. It is used in high value/high performance large RC model aircraft and turbine powered helicopters. That particular engine has a max RPM of 160,000 which is unbearably fast. Obviously that is a whole different realm from piston engines, as there is only one moving part but it is incredible to say the least. For some frame of reference, the Rolls Royce Olympus Afterburning Turbojet has a idle RPM of around 8000. I don't know what max RPM is but it's not that much higher. Especially compared to the little engines which have a RPM range of over  100,000.

[Gman_builder]

Current model.

http://imgur.com/a/dxZ88

It doesn't work at all but it's progress XD

This one is trying to demonstrate throttle control. By moving the swash up and down. Instead of tilting it for pitch and roll.

Edited July 27, 2016 by Gman_builder

[Gman_builder]

I worked long and hard last night to produce this:

http://imgur.com/a/yTNQq

It actually runs quick smoothly. Though it is definitely not ready to receive any power from a engine. I am thinking about starting with 1 Juno at low speed and seeing how it handles when it spins.

It has actual linkages and stuff which is awesome. I used thermometers instead of atmosphere thingies so it is quite small as well. Albeit prone to falling apart. One cool thing about control surface powered helicopter rotor heads is that you can control the throttle and stuff with trim for fine movement.

This model also has only 4 individual craft, 1 for each blade, 1 for the swash/linkage assembly, and 1 for the main craft.

I thought about how this could actually be applicable though in a aircraft, and I came to the conclusion that it  can't. If you are trying to control the throttle with control surfaces, it will end up pitching the whole craft as well and vice-versa. We should make a pledge do include the basic controls(WASD Shift Ctrl) in the action group menu so we can fly stuff like this.

 

[Majorjim!]

2 hours ago, Gman_builder said:

I worked long and hard last night to produce this:

http://imgur.com/a/yTNQq

It actually runs quick smoothly. Though it is definitely not ready to receive any power from a engine. I am thinking about starting with 1 Juno at low speed and seeing how it handles when it spins.

It has actual linkages and stuff which is awesome. I used thermometers instead of atmosphere thingies so it is quite small as well. Albeit prone to falling apart. One cool thing about control surface powered helicopter rotor heads is that you can control the throttle and stuff with trim for fine movement.

This model also has only 4 individual craft, 1 for each blade, 1 for the swash/linkage assembly, and 1 for the main craft.

I thought about how this could actually be applicable though in a aircraft, and I came to the conclusion that it  can't. If you are trying to control the throttle with control surfaces, it will end up pitching the whole craft as well and vice-versa. We should make a pledge do include the basic controls(WASD Shift Ctrl) in the action group menu so we can fly stuff like this.

 

Yay you used my thermo/antenna hinge! 

 Still the smallest possible in the game. :-)

[Gman_builder]

5 minutes ago, Majorjim said:

Yay you used my thermo/antenna hinge! 

 Still the smallest possible in the game. :-)

Yup! Hey @Majorjim, your pretty good at this kind of stuff right? Maybe you should give collective pitch heli rotors a try. I'd like to see what you come up with!

[Majorjim!]

16 minutes ago, Majorjim said:

Yay you used my thermo/antenna hinge! 

 Still the smallest possible in the game. :-)

Well thanks man. 

 I would love to hae a go at rotor craft but I am focused 100% on my very tricky constellation build. When that is done I will have a look at these and my tank track craft. So for now I will just sit back and enjoy what you guys are making.