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

[Azimech]

7 hours ago, The Optimist said:

30 panthers

 

Oi! That fuel consumption

[Azimech]

2 hours ago, selfish_meme said:

at the moment with no cheats enabled and two full 1.25 to mk2 tanks and a couple of mk0's that are also full it can do about 60+ms, with a bit of trimming I can get the weight down again by quite a bit, and I think the engines could be tweaked further, there are only 6 junos in each, 88 parts and 7 tons wet. The bearing is sweet even better than mine was, but I guess if you wack some panthers on it you might upset it.

That's almost a given, especially with afterburner enabled. I've come to love the Juno, even if you need 6 times as many to replace one basic jet. The Panther is lousy for anything subsonic and what we build will never go transonic anyway.

 

25 minutes ago, Gman_builder said:

I TOTALLY agree with you in all those aspects, but I was just saying if you want to get more performance you can change some stuff.

Yo Azimech, why does this happen?

 

Funny just yesterday I was busy with a similar design using a MK2 cargo bay. My guess it's because of a friction spike that gives the whole plane a jolt. check engine RPM ... if it's jumping it's feeding it's own torque to the airframe.

Possible causes:
Too much bearing clearance (low freq vibration) or too little (high freq vibration) ... and MK1 parts are too large to really fit ... I was really disappointed when I saw that.

 

Other news: Yesterday I saw one of my engines do 49 rad/s before it failed. I'm redesigning my thrust bearing again and using new blower tech. RPM has such a huge influence on engine power that I'm going to ask @NathanKell if the standard value can be increased from 30 to 50 rad/s, which is the PhysX limit anyway.
Oh what do you know ... I just did.

Edited June 17, 2016 by Azimech

[Gman_builder]

2 hours ago, Azimech said:

That's almost a given, especially with afterburner enabled. I've come to love the Juno, even if you need 6 times as many to replace one basic jet. The Panther is lousy for anything subsonic and what we build will never go transonic anyway.

 

Funny just yesterday I was busy with a similar design using a MK2 cargo bay. My guess it's because of a friction spike that gives the whole plane a jolt. check engine RPM ... if it's jumping it's feeding it's own torque to the airframe.

Possible causes:
Too much bearing clearance (low freq vibration) or too little (high freq vibration) ... and MK1 parts are too large to really fit ... I was really disappointed when I saw that.

 

Other news: Yesterday I saw one of my engines do 49 rad/s before it failed. I'm redesigning my thrust bearing again and using new blower tech. RPM has such a huge influence on engine power that I'm going to ask @NathanKell if the standard value can be increased from 30 to 50 rad/s, which is the PhysX limit anyway.
Oh what do you know ... I just did.

how can I remedy the vibration issues? it seems like whenever I build engines the hit boxes on the wheels are very strange and buggy. Also, what did you just do?

[Azimech]

39 minutes ago, Gman_builder said:

how can I remedy the vibration issues? it seems like whenever I build engines the hit boxes on the wheels are very strange and buggy. Also, what did you just do?

Do you have wheels positioned on any other angle than dead straight on your turbine shaft? It might be solved in 1.1.3 but in 1.1.2 wheels have a bug which makes the wheels & suspension jolt violently. Also, finding the right spring/damper ratio is a matter of trial & error.

Also I suspect a longer shaft makes it more stable on the longitudinal axis but it also gives more strain on the bearings while cornering. I'm experimenting with a few different shaft setups and my findings are as follows: using the MK1 crew cabin, having excellent crash tolerance but being very heavy, is generally more stable, more rigid and is less subject to high frequency radial vibration but when it does it puts more strain on the bearings, further more there is power loss in the general setup and overall higher craft mass, not to mention a big strain on the bearings at high speed cornering. A new method I've discovered is to build a shaft using the MK1 structural fuselage (which was my previous favourite choice due to the high crash tolerance in 0.90 - 1.0.4) and use the claw to slide it into place of the bearing wheels. The claw has a mass of only 75 kg but a very high crash tolerance and a slightly larger diameter than the 1.25 parts. This setup is 1550 kg lighter than the MK1 crew cabin shaft but it has it's own problems: tendency to high freq radial po-go, more flexible joints which can bend the shaft and give it a mass imbalance and the right spring/damper setup becomes even more important. But ... engine efficiency improves a lot!

And what I did ... I mentioned NathanKell and so he received a notification.

Edited June 17, 2016 by Azimech

[EpicSpaceTroll139]

5 hours ago, Gman_builder said:

Well, if you've seen my car you should know that gears do work. But I don't think they work very well or even at all at the high speeds required to lift a helicopter. ... ... Back to gears though, I think the problem arises in the collisions between the gear teeth. as they hit each other pretty hard even at low speeds. I used the structural panels because they have one of the highest crash tolerances. Wing segments and other similar parts with low crash tolerances don't work at all as gears.

I actually found that gears made from thermometers work quite well even at high speeds (I found this out while working on a helicopter with intermeshing rotors. I never bothered to complete it though. If someone wants it I could however do so)

[Gman_builder]

35 minutes ago, Azimech said:

Do you have wheels positioned on any other angle than dead straight on your turbine shaft? It might be solved in 1.1.3 but in 1.1.2 wheels have a bug which makes the wheels & suspension jolt violently. Also, finding the right spring/damper ratio is a matter of trial & error.

Also I suspect a longer shaft makes it more stable on the longitudinal axis but it also gives more strain on the bearings while cornering. I'm experimenting with a few different shaft setups and my findings are as follows: using the MK1 crew cabin, having excellent crash tolerance but being very heavy, is generally more stable, more rigid and is less subject to high frequency radial vibration but when it does it puts more strain on the bearings, further more there is power loss in the general setup and overall higher craft mass, not to mention a big strain on the bearings at high speed cornering. A new method I've discovered is to build a shaft using the MK1 structural fuselage (which was my previous favourite choice due to the high crash tolerance in 0.90 - 1.0.4) and use the claw to slide it into place of the bearing wheels. The claw has a mass of only 75 kg but a very high crash tolerance and a slightly larger diameter than the 1.25 parts. This setup is 1550 kg lighter than the MK1 crew cabin shaft but it has it's own problems: tendency to high freq radial po-go, more flexible joints which can bend the shaft and give it a mass imbalance and the right spring/damper setup becomes even more important. But ... engine efficiency improves a lot!

And what I did ... I mentioned NathanKell and so he received a notification.

This is getting very complicated   :|

[Azimech]

4 minutes ago, EpicSpaceTroll139 said:

I actually found that gears made from thermometers work quite well even at high speeds (I found this out while working on a helicopter with intermeshing rotors. I never bothered to complete it though. If someone wants it I could however do so)

Someone made one in 0.90, can be found somewhere in the early pages of this topic.

 

5 hours ago, Gman_builder said:

Well, if you've seen my car you should know that gears do work. But I don't think they work very well or even at all at the high speeds required to lift a helicopter. Also, keep in mind that the theoretical speed limit for props is around 50 RAD/s So I don't know how you'll achieve 4800 KN under the current limitations of KSP physics. Back to gears though, I think the problem arises in the collisions between the gear teeth. as they hit each other pretty hard even at low speeds. I used the structural panels because they have one of the highest crash tolerances. Wing segments and other similar parts with low crash tolerances don't work at all as gears.

 

To give you and others an insight: there are two major flaws in KSP/Unity at this time: joint flexibility and collider stiffness based on part mass instead of material type. In other words when using gears, higher mass provides better collision behaviour. I discovered this when building my piston engines, with low piston mass they would often stick through the cylinder wall on the power stroke. This is a major problem for engineering. Part friction is another hurdle, seems to me all parts use the same standard Unity physics material, which is way too high when used in gears. I tried building a dual turboshaft helicopter like the Mil-Mi 24 last year but all power got lost due to teeth biting each other and entangling colliders.

[Azimech]

11 minutes ago, Gman_builder said:

This is getting very complicated   :|

And a nice challenge :-D

[Gman_builder]

22 minutes ago, Azimech said:

Someone made one in 0.90, can be found somewhere in the early pages of this topic.

 

To give you and others an insight: there are two major flaws in KSP/Unity at this time: joint flexibility and collider stiffness based on part mass instead of material type. In other words when using gears, higher mass provides better collision behaviour. I discovered this when building my piston engines, with low piston mass they would often stick through the cylinder wall on the power stroke. This is a major problem for engineering. Part friction is another hurdle, seems to me all parts use the same standard Unity physics material, which is way too high when used in gears. I tried building a dual turboshaft helicopter like the Mil-Mi 24 last year but all power got lost due to teeth biting each other and entangling colliders.

When making geared vehicles, finding the right mesh is essential. If the teeth are to close to each other they grind and lose power. Wheras if they are to far apart they can skip or shred. Ive got some real gears for yall in a minute....

I PRESENT TO YOU ALL

THE WORLDS FIRST

4 WHEEL DRIVE STOCK TURBOSHAFT CAR

POWERED BY A SINGLE GEARED TURBOSHAFT ENGINE

It is also TECHNICALLY the fastest in the world of its kind.  

Although my 2 wheel drive version of this exact car is about 20 times faster...
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I sleep now

Edited June 17, 2016 by Gman_builder

[Azimech]

Great job, Gman_Builder!

Also ... 1.1.3?!

[Gman_builder]

1 minute ago, Azimech said:

Great job, Gman_Builder!

Also ... 1.1.3?!

idk I was just assuming

@AzimechI have some concepts in my brain for a stock steering system. I will start work tomorrow

[sdj64]

17 hours ago, selfish_meme said:

This is not beating any speed records yet, I used @sdj64's engine, as it was very similar to my own, but better. This craft has only a tiny amount of SAS because it's propellers spin opposite ways and tiny control surfaces. So unlike most turboprops it remains controllable and stable. It is a very early work but shows a lot of promise as an actual practical plane, I have another four engine cargo version as well that is almost finished which should be faster and be able to carry cargo. This is in stock aero, I even landed it, a broken prop doesn't count does it?

Download

 

Cool, someone's using my engine!  I pushed a revised version past 140 m/s (with minimum drag) with a variable pitch prop and more jets.  It gained speed to ~120 then started gaining speed much more slowly as the fuel drained, so the key to higher performance might be weight reduction, or using multiple engines. @Majorjim this one takes off and flies (barely, at 45-50 m/s) with stock drag.

This thread seems more lively than the challenge one, and I'm still nowhere near 200 m/s so I thought I would post here.

https://www.dropbox.com/s/3m8afj1vkn67nal/Skipper Corsair V1_1.craft?dl=0

[Majorjim!]

8 minutes ago, sdj64 said:

this one takes off and flies (barely, at 45-50 m/s) with stock drag.

Yeah it did take off and fly but adjusting for the engine torque causes it to stall.

[selfish_meme]

1 hour ago, sdj64 said:

Cool, someone's using my engine!  I pushed a revised version past 140 m/s (with minimum drag) with a variable pitch prop and more jets.  It gained speed to ~120 then started gaining speed much more slowly as the fuel drained, so the key to higher performance might be weight reduction, or using multiple engines. @Majorjim this one takes off and flies (barely, at 45-50 m/s) with stock drag.

This thread seems more lively than the challenge one, and I'm still nowhere near 200 m/s so I thought I would post here.

https://www.dropbox.com/s/3m8afj1vkn67nal/Skipper Corsair V1_1.craft?dl=0

I noticed the bearing spins faster if you drain the fuel out of the mk0 tank, also I think the vanes might be unnecessary, I had one almost taking off at 35ms in stock aero last night with the jets just pushing on the tank, only using 4 junos. With just two empty mk0 tanks plus nosecones and 8 junos it might get somewhere. plus you can stick it all in structural fuselages with a big aerodynamic prop hub out front.

Edited June 17, 2016 by selfish_meme

[Azimech]

12 minutes ago, selfish_meme said:

I noticed the bearing spins faster if you drain the fuel out of the mk0 tank, also I think the vanes might be unnecessary, I had one almost taking off at 35ms in stock aero last night with the jets just pushing on the tank, only using 4 junks. With just two empty mk0 tanks plus nosecones and 8 junos it might get somewhere. plus you can stick it all in structural fuselages with a big aerodynamic prop hub out front.

Yes, lower mass means less strain on the bearings thus better efficiency. The turbine blades or vanes as you call them ... they provide an advantage and disadvantage. KSP has flexible joints and with the centrifugal force it means blades start to move radially outwards with increasing angular velocity. This is what limits most turboprop designs and that's a bummer because higher RPM means higher max speed. The advantage is this: a floating turbine blade has a larger diameter than when resting at original position on the shaft. A larger diameter means a higher torque when a thrust vector of a blower is acting on it. No blades means you can't take advantage of this [bug/feature] and will permit high RPM's up to the PhysX limit but with a much lower torque.

Edited June 17, 2016 by Azimech

[Majorjim!]

This quest for higher speed, where does it end?  

[NathanKell]

@Azimech I had some instability above 30 rad/s when I tested. But let me know how it behaves at a higher value, it is tunable in Physics.cfg after all.

[Azimech]

1 minute ago, Majorjim said:

This quest for higher speed, where does it end?  

If the new aero physics are anywhere realistic ... at transonic :-)

[selfish_meme]

13 minutes ago, Azimech said:

Yes, lower mass means less strain on the bearings thus better efficiency. The turbine blades or vanes as you call them ... they provide an advantage and disadvantage. KSP has flexible joints and with the centrifugal force it means blades start to move radially outwards with increasing angular velocity. This is what limits most turboprop designs and that's a bummer because higher RPM means higher max speed. The advantage is this: a floating turbine blade has a larger diameter than when resting at original position on the shaft. A larger diameter means a higher torque when a thrust vector of a blower is acting on it. No blades means you can't take advantage of this [bug/feature] and will permit high RPM's up to the PhysX limit but with a much lower torque.

It seems that would not provide much of an advantage except if the jet wash was not pushing on the whole surface in the first place, it was offset slightly. If the jets wash is hitting the whole surface then there is no advantage to that surface moving. It does not seem that the game models the difference between a flat surface and round surface when considering jet wash, and if the jet wash is not being offset from the end of the tank it should be just as efficient.

[Azimech]

1 minute ago, NathanKell said:

@Azimech I had some instability above 30 rad/s when I tested. But let me know how it behaves at a higher value, it is tunable in Physics.cfg after all.

Thanks for the reply! I've seen instability around 50 rad/s and higher, it might depend on the CPU but unable to test it yet. I'm using a Pentium G2140 which had a very good core performance for it's price a few years ago.

Some people don't like the idea of changing any values in any kind of configuration because they feel it won't be "stock" and they feel a lot of users - who otherwise would have an interest in a different kind of engineering - might be left out because they are ... insecure or something.
Anyway ... would be helpful for future console users as well ... they won't be able to change files, right?

4 minutes ago, selfish_meme said:

It seems that would not provide much of an advantage except if the jet wash was not pushing on the whole surface in the first place, it was offset slightly. If the jets wash is hitting the whole surface then there is no advantage to that surface moving. It does not seem that the game models the difference between a flat surface and round surface when considering jet wash, and if the jet wash is not being offset from the end of the tank it should be just as efficient.

Maybe I'm wrong but you could build your own test setup. My experience ... is a little different :-)

[Gman_builder]

17 minutes ago, NathanKell said:

@Azimech I had some instability above 30 rad/s when I tested. But let me know how it behaves at a higher value, it is tunable in Physics.cfg after all.

Azimech and I have been experimenting with engines that spin at 43 RAD/s or higher and have so far encountered no major bugs or instability at those speeds.

[selfish_meme]

6 minutes ago, Azimech said:

Maybe I'm wrong but you could build your own test setup. My experience ... is a little different :-)

You obviously have much more experience with it than I do, though I was surprised how efficient it was, plus saving on parts, complexity, weight and vibration.

[Majorjim!]

Just now, Azimech said:

Some people don't like the idea of changing any values in any kind of configuration because they feel it won't be "stock" and they feel a lot of users - who otherwise would have an interest in a different kind of engineering - might be left out because they are ... insecure or something.

Lol, no man, it's that a stock craft should be usable by anyone with a stock game. Ie, as is, not changed in any way. it's that simple.

 

Just now, Azimech said:

If the new aero physics are anywhere realistic

It's not, but it might get better!

Edited June 17, 2016 by Majorjim

[Gman_builder]

@sdj64I was trying to make a engine in the MK2 cargo bay and only got around 25 RAD/s. Then I started getting serious kraken attacks. What's the secret?

[selfish_meme]

8 minutes ago, Gman_builder said:

@sdj64I was trying to make a engine in the MK2 cargo bay and only got around 25 RAD/s. Then I started getting serious kraken attacks. What's the secret?

He was using the same method I was, but instead of putting the thermometers around the mk0 tank he puts nosecones on the tank and forms the thermometers into caps, it is very smooth. With two mk0 tanks end to end there is enough room for 4 blowers length, plus if you stick the end out you can attach the props directly to the nosecones as well, saving parts and suspended bits hanging way forward.

It is also slim enough to fit inside a structural fuselage instead of a cargo bay if you don't use blades.

Edited June 17, 2016 by selfish_meme