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


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8 hours ago, Castille7 said:

Thank you! The speeds are terrible atm (9 m/s surface travel not speed..haha) it's really a test model for me to learn all the what works and what don't at the same time getting pointers from you peeps. This is why most are going to smaller aircraft and I might even have to scrap Hurricane Hunter......hope not. I will be adding more shaft and panthers after I finish testing the pitch on these props. My hopes are to not stretch the blades off the hubs to keep it looking more realistic. If the blades need help I am considering basic fins on the inside of these to help with the push. I hope to have some better results this weekend. @Azimech makes this stuff look easy...haha but we know he's had his hours of trial and error :D.

Not sure if this bit of info will help much, but in every turboprop rendition I've made I've noticed that centrifugal stretching is a huge part of getting the correct lift. Example, I always enable all blades to strut to root parts but if Rigid part attachment is clicked, the blades will produce almost no power at all. In fact, every turboprop I've made can be disabled simply by making the blades rigid, I don't know why it works the way it does xD

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55 minutes ago, Krog34 said:

Not sure if this bit of info will help much, but in every turboprop rendition I've made I've noticed that centrifugal stretching is a huge part of getting the correct lift. Example, I always enable all blades to strut to root parts but if Rigid part attachment is clicked, the blades will produce almost no power at all. In fact, every turboprop I've made can be disabled simply by making the blades rigid, I don't know why it works the way it does xD

That's why angular velocity readout is so important to have. Rigid part attachment does something with the physics, it works as some kind of brake. Engines typically run at 1/4 or less than their usual speed.

Time to issue a bug report.

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On 9/22/2017 at 3:28 PM, Krog34 said:

Not sure if this bit of info will help much, but in every turboprop rendition I've made I've noticed that centrifugal stretching is a huge part of getting the correct lift. Example, I always enable all blades to strut to root parts but if Rigid part attachment is clicked, the blades will produce almost no power at all. In fact, every turboprop I've made can be disabled simply by making the blades rigid, I don't know why it works the way it does xD

Its because if the blades increase in diameter that means the tip RPM increases and they produce more thrust. 

That and the fact that rigid attachment screws with the RPM limiter.

Edited by Gman_builder
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31 minutes ago, Gman_builder said:

Are yall up for a community project?

Like what? :)

18 hours ago, Gman_builder said:

I may have lost my speed record but I definitely hold the record for most part intensive turboprop at 1016 parts! I doubt anyone will be taking this one away anytime soon! :D 

You can never really be so sure with this game... :wink:

Edited by PaperAviator
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Just now, PaperAviator said:

Like what? :)

Standardizing basic components like bearings and props as sub-assemblies to make assembly of new engines easier.

There could be different sizes and load tolerances and whatnot but i think a baseline standard could be really useful if the parts are reliable.

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4 minutes ago, Gman_builder said:

Standardizing basic components like bearings and props as sub-assemblies to make assembly of new engines easier.

There could be different sizes and load tolerances and whatnot but i think a baseline standard could be really useful if the parts are reliable.

I dunno... There already is sort of a standard with the bearings... like the thermometer-and rcs ball hinge and the antenna-and solar panel one. Also, would standardizing bearings really be practical for the community? Ksp is a game of trial and error, after all :wink:

On the other hand... I'm only just beginning to build reliable hinges and turboprop vehicles, having premade subassemblies would be useful... 

Edited by PaperAviator
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Just now, PaperAviator said:

I dunno... There already is sort of a standard with the bearings... like the thermometer-and rcs ball hinge and the antenna-and solar panel one. Also, would standardizing bearings really be practical for the community? Ksp is a game of trial and error, after all :wink:

On the other hand... I'm only just beginning to build reliable hinges and turboprop vehicles, having premade subassemblies might be useful... 

yeah exactly, everybody builds the same part but Azimech's is more reliable than Mine or Klond's can handle higher RPM than EpicSpacetrolls's.

Finding the optimal design and then everybody just using that one as a sub-assembly would work wonders for build time and keep us from pulling our hair out.

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36 minutes ago, Gman_builder said:

yeah exactly, everybody builds the same part but Azimech's is more reliable than Mine or Klond's can handle higher RPM than EpicSpacetrolls's.

Finding the optimal design and then everybody just using that one as a sub-assembly would work wonders for build time and keep us from pulling our hair out.

TBH, this would be an interesting idea...

Then everyone has a favorite engine "manufacturer", which could be weird maybe.

Edited by qzgy
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Hurricane Hunter
Update 09.24.2017

This update is a progress report. I am now getting the much needed RPM's for the Hurricane Hunter Engines I've been working on. Added more shaft and Panthers as I was planing. Still working with the Structural Fuselage, RCS Balls and Chutes.

 

RUHIUnY.png

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16 hours ago, Gman_builder said:

Standardizing basic components like bearings and props as sub-assemblies to make assembly of new engines easier.

There could be different sizes and load tolerances and whatnot but i think a baseline standard could be really useful if the parts are reliable.

Sounds like neat idea. Perhaps cubic and octagonal struts would be good interface pieces because, due to their "physics less" nature, joints between them don't bend, so you could string several components together and have them act as one rigid component.

I've been regularly using a subassembly version of the thermo-rcs hinge cage component on a cubic strut. Might dig that out and see if that can be useful.

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I don't have the time to fully analyze his reply and it does help if you read the topic. I'm interested to see what you guys think of this. My basic premise: too much reductionism.

 

2 hours ago, EpicSpaceTroll139 said:

Sounds like neat idea. Perhaps cubic and octagonal struts would be good interface pieces because, due to their "physics less" nature, joints between them don't bend, so you could string several components together and have them act as one rigid component.

I've been regularly using a subassembly version of the thermo-rcs hinge cage component on a cubic strut. Might dig that out and see if that can be useful.

While the RCS balls are not "physics less" and much more heavy than the cubic and octagonal struts, they have the same basic joint properties. Which is great.

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3 hours ago, Azimech said:

I don't have the time to fully analyze his reply and it does help if you read the topic. I'm interested to see what you guys think of this. My basic premise: too much reductionism.

Took a read through it. Don't see the point being made. I mean, isn't that what all props do anyway? Yank on something to pull the plane forward?

Personally, don't find props cheaty.

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I was a bit perplexed by the argument that the game physics results in the propeller shoving the plane in a way that violates Newton's 2nd and 3rd laws.

If that we're true, then I could also fly a larger jet plane with smaller engines by decoupling my engines and keeping them captive in cages... But that doesn't work at all.

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How well do these engines work in the latest version of KSP? Also, what is the new way of building the bearings and such, because I keep seeing people referencing a new bearing design. Last time I tried building a turboprop it just torqued the plane so much that it was not flyable, also barely had enough power to even get off the ground.

 

Thank you, Solaris

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On 9/25/2017 at 4:08 PM, Azimech said:

I don't have the time to fully analyze his reply and it does help if you read the topic. I'm interested to see what you guys think of this. My basic premise: too much reductionism.

 

An update on this. Through a long private chat debate and some physics experiments in KSP, we have come to a conclusion that neither of us were entirely correct. Expect a fully fledged post on some interesting KSP experiments that demonstrates that stock props in of themselves do not violate physics, but reaction wheels break physics even worse than we thought!

 

@lgsolaris I believe most of the turboprops and helicopters you'll find here are up to date (except perhaps a couple of the really clunky looking (no offense Azi) planes and helis in the first post, which were some of the first turboprops and turboshaft ever made) and will work in the current version of KSP. I myself have not used the new RCS ball bearing much, mostly because I haven't dedicated much time to learning how to make one reliably. They appear simple enough that I could probably figure it out if I tried, but for my mechanical contraptions the solar panel - antenna bearing has been sufficient, so I haven't felt a strong urge to switch over. If I built more planes, which tend to have higher bearing stresses, I would probably have already switched. @klond and @Azimech might be able to help you with those.

Anyways, from my experience with turboprops planes, I would make sure I have a good sized wingspan with my landing gear placed as far out as possible to help deal with the torque. You'll probably want to trim using alt-q or alt-e against the torque, though remember you will need less trim when you get up to speed. Once you've got those you need to fiddle with the number of blades and the blade pitch quite a lot to find the configuration that gets the best thrust from your propeller. It's a lot of trial and error, but it's so rewarding when it finally works! :)

 

Edit: you can find many working turboprops and helicopters here

https://kerbalx.com/hangars/6515

Edited by EpicSpaceTroll139
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  • 2 weeks later...

There was a question in the electric prop topic about prop design so I wrote some stuff down.

 

1 hour ago, quasarrgames said:

Hey guys, what's the best way to maximize propeller speed? My propeller planes can't go above 30m/s for some reason.

AKA, what's the best way to mimimize friction and maximize lift for an engine, and keep this lift at high speeds?

 

The science behind KSP propellers basically follows real life although it seems simplified just like NeoAero is compared with FAR or real life. Generally speaking: higher angular velocity (from now on called rpm) means more potential to convert it into thrust, just like the wing of an airplane produces more lift at higher speeds.

After rpm there is another crucial element which is a departure of the behaviour of airplane wings: angle of attack. In regular terminology: propeller pitch.

I'm assuming right now you have a fixed propeller.

A fixed propeller only works efficiently at a single airplane speed corresponding with its rpm. This means an efficient propeller is able to change its pitch. For taking off you use a "fine" pitch, compare it with an airplane with a low AOA. Great for building up speed at first but soon you discover the airplane won't accelerate anymore. This is because the airflow hits the propeller blades like you're trying to fly forward with the nose of the airplane pointing straight down. So we change the pitch in steps or fluently, always observing engine rpm. This can be compared with changing gears in a car. Every propeller has an rpm "sweet spot" for best thrust/drag ratio, you want to discover what speed that is and during powered flight, try to keep close to it. When changing the pitch to more "coarse" you'll immediately see two things: a drop in rpm and an increase in airplane speed.

If you're unable to accelerate your airplane beyond a specific speed it can be due to a number of things:

  1. The drag of your airframe is too high.
  2. The mass of your airplane is too high.
  3. Your engine is not powerful enough.
  4. The diameter of your propeller is too small.
  5. You don't have enough control authority for the pitch of your propeller or your standard prop pitch is too fine.
  6. You don't have enough propeller blades.
  7. Your propeller is going transonic.

Coming back to the subject of changing gears in a car: we use low gears for acceleration or when climbing a mountain. Same with airplanes. When diving or when trying to make best of a glide when the engine has died, we use a pitch as coarse as possible to minimize resistance.

I recommend installing V.O.I.D. for an angular speed readout of your engine/propeller in rad/s. Keep in mind KSP is unable to have speeds higher than ~50 rad/s (477 rpm). Above that speed physics go gaga, joints become spaghetti and you generally end up with a RUD, SMEF or giant explosion.

Hope this helps.

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On 9/27/2017 at 7:17 PM, lgsolaris said:

How well do these engines work in the latest version of KSP? Also, what is the new way of building the bearings and such, because I keep seeing people referencing a new bearing design. Last time I tried building a turboprop it just torqued the plane so much that it was not flyable, also barely had enough power to even get off the ground.

 

Thank you, Solaris

We've started using RCS ball bearings instead of standard wheeless bearing or wheeled bearings. The RCS balls have minimum friction and you cn make them really compact.

If the plane had wicked torque you can try a couple of things:

1. Lengthen the wings

2. Add a counterweight on one wingtip

3. Reduce engine RPM until you build up enough speed to counter torque with control surfaces

4. Add more ailerons.

Adding more wing surface will also help with flight performance, you won't have to go as fast in order to take off. Once your in the air most torque problems are usually solved.

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14 minutes ago, Azimech said:

That also works.

And don't forget to try different propeller blade angles. You'll notice they affect torque as well.

Also an extra action grouped aileron on one side, once above 100ms I don't tend to need any extra control, so using an extra aileron that can be undeployed helps with top speed

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