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

[Pds314]

6 minutes ago, Gman_builder said:

I added a screenshot and some stuff to my earlier response you should check it out.

I meant, i was going to try to increase the speed off my stable 48 rad/s 5 bladed prop to just get 5 more m/s out of the plane. Mainly by weight reduction and stuff.

Ah. Alright. Cool

Wow. That's a light plane for such a large engine. Then again, it is a single-engine, and not twin..

Got to about 200 before neglect caused an engine explosion. It was still accelerating and climbing somewhat.

Edited July 17, 2016 by Pds314

[Gman_builder]

11 minutes ago, Pds314 said:

Ah. Alright. Cool

Wow. That's a light plane for such a large engine. Then again, it is a single-engine, and not twin..

Got to about 200 before neglect caused an engine explosion. It was still accelerating and climbing somewhat.

The thing with Juno's is that they perform a lot better the closer you are to sea level. So when ever i do my speed runs i try to get as low as i can safely for maximum thrust out of all the Junos.

On the downside though, being closer to sea level means more soupy air and more drag. Causing your plane to slow down.

Can someone calculate a formula for the optimal altitude based on blower count, blower efficiency, blower throttle curve(i think), plane weight, and airframe design (drag created by airframe itself)

Can your plane continue on one engine?

Edited July 17, 2016 by Gman_builder

[Pds314]

1 minute ago, Gman_builder said:

The thing with Juno's is that they perform a lot better the closer you are to sea level. So when ever i do my speed runs i try to get as low as i can safely for maximum thrust out of all the Junos.

On the downside though, being closer to sea level means more soupy air and more drag. Causing your plane to slow down.

Can someone calculate a formula for the optimal altitude based on blower count, blower efficiency, blower throttle curve(i think), plane weight, and airframe design (drag created by airframe itself)

Can your plane continue on one engine?

It can continue to fly (if I shut down the broken engine to prevent random thrust from the unbalanced jets), but not well. It veers to one side unless constantly corrected, and using controls to prevent that bleeds energy alarmingly quick, so yes, it can, but no, it won't be setting any records while doing so. I have actually taken off and reached 140 m/s on one engine before.

[Gman_builder]

3 minutes ago, Pds314 said:

It can continue to fly (if I shut down the broken engine to prevent random thrust from the unbalanced jets), but not well. It veers to one side unless constantly corrected, and using controls to prevent that bleeds energy alarmingly quick, so yes, it can, but no, it won't be setting any records while doing so. I have actually taken off and reached 140 m/s on one engine before.

Well you definitely beat the record for engine out top speed I guess. Your endurance is obviously doubled as well, so i challenge you to beat the real life engine out endurance record of 177 minutes set by a Boeing 777. Just use pilot assistant to set your heading and bank level and go eat lunch or something.

Edited July 17, 2016 by Gman_builder

[Pds314]

4 minutes ago, Gman_builder said:

Well you definitely beat the record for engine out top speed I guess. Your endurance is obviously doubled as well, so i challenge you to beat the real life engine out endurance record of 177 minutes set by a Boeing 777. Just use pilot assistant to set your heading and bank level and go eat lunch or something.

LOL. That would burn my entire stock fuel supply unless it was at altitude, and I'm not sure I can fly at altitude with an engine out.

On a related note, what was the speed record again?

Top speed: 232.2 m/s, still accelerating, but an engine blew 5 seconds later.


 

Edited July 17, 2016 by Pds314

[Gman_builder]

5 minutes ago, Pds314 said:

LOL. That would burn my entire stock fuel supply unless it was at altitude, and I'm not sure I can fly at altitude with an engine out.

On a related note, what was the speed record again?

Top speed: 232.2 m/s, still accelerating, but an engine blew 5 seconds later.


 

Wow nice! The official record is 235 m/s.

So, in yours and Azimech's runs, your engine actually exploded. But when i did my run, (230 m/s) the plane actually just stopped accelerating. Which is cool. I think i can mess with the prop pitch for more speed but i'll leave that until tomorrow. I have got to get some sleep

goodnight

[Pds314]

42 minutes ago, Gman_builder said:

Oh gawd.

Oh gawd please no

managing one small turboshaft is a challenge in of itself let alone several massive ones. Modded turboshafts generally have worse performance than stock ones. I know from experience.

 

Who ever said it would be a modded turboshaft? Just make a giant stock one correctly sized for use with 2x2 HX.

2 minutes ago, Gman_builder said:

Wow nice! The official record is 235 m/s.

So, in yours and Azimech's runs, your engine actually exploded. But when i did my run, (230 m/s) the plane actually just stopped accelerating. Which is cool. I think i can mess with the prop pitch for more speed but i'll leave that until tomorrow. I have got to get some sleep

goodnight

Not just the engine. The entire plane aerodisintegrated as a result of wing damage.

[Pds314]

New record! 237.0 m/s and in a slight climb. It didn't precisely stop accelerating at this point, but it did get very bad at it. I think I may have set the prop pitch too high/cautiously. I set it at 129, which meant that around here it was only achieving 47 rads/s.

A note: the fuel meter is fairly low. That's because I started the plane with only 35 tonnes / 7000 units of fuel. I.E. it only burned about 6 tonnes, not 190 or something.



Of note is that, since the effective radius of the prop is about 3.25 meters during the screenshot, and the turn rate is about 47 rads/s, the speed of the prop blades is more like 282 m/s, which means that they're definitely encountering transonic airflow. Not sure to what extent stock models transonic airflow, but this could impose somewhat of a barrier.

Hmm.. come to think of it, if I can make it fly safely at 230 m/s at full fuel load, it could fly for quite awhile. That gives it a potential range of something like a bit over a thousand kilometers, and at altitude, this could have a range in excess of 3000.

Then again, it may not be able to reach such high speeds at full fuel.

Edited July 17, 2016 by Pds314

[Azimech]

Congrats!

[life_on_venus]

Hi guys, I've had my eye on this thread a while.

I've been interested in this tech and have made some stock turboprops before with simple bearings (landing gear around 0.625m mono tanks). The engines did not produce a lot of power but that was with default drag settings. I'm going to try to make my own low part count engines from now on, hopefully using some of the knowledge I've gained from this discussion

I know that this is sort of going outside the scope of this thread, however:

As you might know, the infernal robotics mod allows free-spinning bearings that mean the propeller remains a part of the parent craft. Because of this I've been able to successfully use the "Deploy" function of control surfaces to give a collective/pitch control for propellers, still using a stock-like blower and turbine assembly.

That's all,

Venus

[Pds314]

1 minute ago, life_on_venus said:

Hi guys, I've had my eye on this thread a while.

I've been interested in this tech and have made some stock turboprops before with simple bearings (landing gear around 0.625m mono tanks). The engines did not produce a lot of power but that was with default drag settings. I'm going to try to make my own low part count engines from now on, hopefully using some of the knowledge I've gained from this discussion

I know that this is sort of going outside the scope of this thread, however:

As you might know, the infernal robotics mod allows free-spinning bearings that mean the propeller remains a part of the parent craft. Because of this I've been able to successfully use the "Deploy" function of control surfaces to give a collective/pitch control for propellers, still using a stock-like blower and turbine assembly.

That's all,

Venus

I think Azimech tried IR bearings and they worked well up to about 20 rads/s or something but then had issues.

[Pds314]

I made a Corsair! It's not too far off accurate weight and size. Actually, I think the real thing may have a bigger diameter! (though the engine had a smaller weight, more on par with my Screacher 3x1 or 4x1 than the 6x1). I can fly it using MAF, which makes me wonder if the AI pilot could fly it while I periodically adjust prop pitch.

Best of all, it's 62 parts and not one is a fuel line or strut. To be fair, it is quite overweight when fueled, and although the engine is fairly powerful, I've yet to reach over 110 m/s in level flight, probably because the prop pitch being too high turns the efficiency to nothing.

Edited July 17, 2016 by Pds314

[Pds314]

Hmm.. I've been thinking: is it ever sensible to use Panthers instead of Junos for their extra ISP?

The basic problem is size. Panthers are big, which, for a given engine radius, decreases the maximum torque radius, killing efficiency.

But they are also 40.6% more fuel efficient.

So if you can avoid reducing the torque radius by 29% or more, the panther is more fuel efficient, HOWEVER, with a reduced fuel torque radius, the engine is less powerful as well. I.e. an engine with 12 Panthers at a 1 meter torque radius is less powerful and heavier than a less fuel efficient engine with 48 Junos at a 1.2 meter radius.

 

Overall, if fuel efficiency is a concern, it appears Panthers are usually less efficient than Junos when extra mass required for power parity is considered.

EDIT: it's even worse than in my example. For a given outer radius and assuming the turbine blades are interior to the blowers, A Panther reduces the torque radius by an absolute minimum of about 1.25 meters, and very likely more, whilst a Juno reduces that radius by about 0.625, possibly a bit less due to their shape.

This means that a typical panther engine has a torque radius minimally 0.625 meters smaller than that of a Juno engine. I.E. A Panther-based Varpulis analogue would have a torque radius of something like 0.675 meters instead of like 1.3. Not only does that eliminate the efficiency advantage of the Panther, it eliminates the the afterburning power advantage as well. And to get the same power, you end up needing about 1 panther for every 2-3 Junos. Not good at all. Even if fuel efficiency is all that's under consideration, the minimum outer diameter at which Panthers are more efficient than Junos appears to be ~7 meters.

Edited July 18, 2016 by Pds314

[sdj64]

I have a new engine!  Incorporating some of the newest tech (physics-less vanes and inside out design) with the Stayputnik bearing, this engine is by far the best power bang for your part count buck so far.  Managing 40 of whatever drunken unit KER uses for RPM, it's a full 25% faster than the prototype Mk3 sized plane that tested the bearing design.  It's also my first engine that I've given a name to: the Bluebeam engine.

And, it's my first prop plane over 200 m/s!

 

Here is the engine without fairing in the VAB.  The shaft was shortened to one structural fuselage in length, reducing bending.

 

I am also putting all my successful turboprops on KerbalX for everyone to download and try out.  Most of them have the outermost ailerons always deployed to counteract roll from the prop.  You can adjust the authority limits of them while in flight to maintain level as you speed up or slow down.

Here's a link to the hangar:  https://kerbalx.com/hangars/9644

 

@life_on_venus Take a look at some of my designs.  Most of them are not quite as refined as the regulars on this thread, but they are consistently low in part count.

[Gman_builder]

8 hours ago, life_on_venus said:

Hi guys, I've had my eye on this thread a while.

I've been interested in this tech and have made some stock turboprops before with simple bearings (landing gear around 0.625m mono tanks). The engines did not produce a lot of power but that was with default drag settings. I'm going to try to make my own low part count engines from now on, hopefully using some of the knowledge I've gained from this discussion

I know that this is sort of going outside the scope of this thread, however:

As you might know, the infernal robotics mod allows free-spinning bearings that mean the propeller remains a part of the parent craft. Because of this I've been able to successfully use the "Deploy" function of control surfaces to give a collective/pitch control for propellers, still using a stock-like blower and turbine assembly.

That's all,

Venus

Some of my original designs from last year used that part and were pretty unsuccessful. Only reaching about 50m/s on a test cart.

 

8 hours ago, Pds314 said:

I think Azimech tried IR bearings and they worked well up to about 20 rads/s or something but then had issues.

It was me who tried them. I briefly went over why they can't be used for multiple reasons a few pages back.

 

4 hours ago, Pds314 said:

Hmm.. I've been thinking: is it ever sensible to use Panthers instead of Junos for their extra ISP?

The basic problem is size. Panthers are big, which, for a given engine radius, decreases the maximum torque radius, killing efficiency.

But they are also 40.6% more fuel efficient.

So if you can avoid reducing the torque radius by 29% or more, the panther is more fuel efficient, HOWEVER, with a reduced fuel torque radius, the engine is less powerful as well. I.e. an engine with 12 Panthers at a 1 meter torque radius is less powerful and heavier than a less fuel efficient engine with 48 Junos at a 1.2 meter radius.

 

Overall, if fuel efficiency is a concern, it appears Panthers are usually less efficient than Junos when extra mass required for power parity is considered.

EDIT: it's even worse than in my example. For a given outer radius and assuming the turbine blades are interior to the blowers, A Panther reduces the torque radius by an absolute minimum of about 1.25 meters, and very likely more, whilst a Juno reduces that radius by about 0.625, possibly a bit less due to their shape.

This means that a typical panther engine has a torque radius minimally 0.625 meters smaller than that of a Juno engine. I.E. A Panther-based Varpulis analogue would have a torque radius of something like 0.675 meters instead of like 1.3. Not only does that eliminate the efficiency advantage of the Panther, it eliminates the the afterburning power advantage as well. And to get the same power, you end up needing about 1 panther for every 2-3 Junos. Not good at all. Even if fuel efficiency is all that's under consideration, the minimum outer diameter at which Panthers are more efficient than Junos appears to be ~7 meters.

A few pages back I posted pics of my panther powered engine.

It had a decent max RPM of around 38 rad/s with 16 panthers all on full afterburner. However it went through fuel far to fast and overheated my atmosphere thingy vains so I had to switch to structural panels which also overheated eventually. On the upside though I got much better FPS because of the low part count.

I converted that exact engine into the Juno powered engine I just showed you yesterday. Which has been extremely powerful and reliable.

So my summary is, panther powered engines will always be outperformed in power and efficiency by Juno powered engines. No matter what design or implementation you use them for, you will always be able to build a Juno powered version that produces more power and is more reliable.

[Pds314]

3 hours ago, sdj64 said:

I have a new engine!  Incorporating some of the newest tech (physics-less vanes and inside out design) with the Stayputnik bearing, this engine is by far the best power bang for your part count buck so far.  Managing 40 of whatever drunken unit KER uses for RPM, it's a full 25% faster than the prototype Mk3 sized plane that tested the bearing design.  It's also my first engine that I've given a name to: the Bluebeam engine.

And, it's my first prop plane over 200 m/s!

 

Here is the engine without fairing in the VAB.  The shaft was shortened to one structural fuselage in length, reducing bending.

 

I am also putting all my successful turboprops on KerbalX for everyone to download and try out.  Most of them have the outermost ailerons always deployed to counteract roll from the prop.  You can adjust the authority limits of them while in flight to maintain level as you speed up or slow down.

Here's a link to the hangar:  https://kerbalx.com/hangars/9644

 

@life_on_venus Take a look at some of my designs.  Most of them are not quite as refined as the regulars on this thread, but they are consistently low in part count.

Wow. Very nice. What sort of weight does the engine have w/o props?

[Pds314]

1 hour ago, Gman_builder said:

A few pages back I posted pics of my panther powered engine.

It had a decent max RPM of around 38 rad/s with 16 panthers all on full afterburner. However it went through fuel far to fast and overheated my atmosphere thingy vains so I had to switch to structural panels which also overheated eventually. On the upside though I got much better FPS because of the low part count.

I converted that exact engine into the Juno powered engine I just showed you yesterday. Which has been extremely powerful and reliable.

So my summary is, panther powered engines will always be outperformed in power and efficiency by Juno powered engines. No matter what design or implementation you use them for, you will always be able to build a Juno powered version that produces more power and is more reliable.

Well, I think at truly absurd sizes like, say, 10 meters in diameter, the argument in favor of using Panthers for efficiency and afterburners as a WEP is pretty good.

 

But yeah, at small sizes, the only possible benefit is part count.

 

I suppose if you're really insane, you could use Vector engines, but the fuel efficiency would be phenomenally poor, and things would overheat almost instantly. There's also the serious question of why anyone ever needs the power of a vector engine, when most of my Juno engines are under-propped. Basically, there's a good reason why I don't always try to maximize the number of blowers. At some point, you end up needing a bigger prop and the whole system just becomes unusable.

Edited July 18, 2016 by Pds314

[Gman_builder]

29 minutes ago, Pds314 said:

Well, I think at truly absurd sizes like, say, 10 meters in diameter, the argument in favor of using Panthers for efficiency and afterburners as a WEP is pretty good.

 

But yeah, at small sizes, the only possible benefit is part count.

 

I suppose if you're really insane, you could use Vector engines, but the fuel efficiency would be phenomenally poor, and things would overheat almost instantly. There's also the serious question of why anyone ever needs the power of a vector engine, when most of my Juno engines are under-propped. Basically, there's a good reason why I don't always try to maximize the number of blowers. At some point, you end up needing a bigger prop and the whole system just becomes unusable.

ATM i'm trying to produce a engine that can run sustainably at 50+ rad/s and beat the current speed record. Which is now 237 m/s. So far I am doing pretty good from starting completely from scratch.

[Gman_builder]

Disaster has struck.

I launched KSP as normal every day to work on the plane.

I have changed nothing since yesterday and all the settings are the same.

Right when I launch I get the "jiggly-prop effect" on my entire aircraft. If I can manage to takeoff without the jiggleyness happening it just explodes for seemingly no reason right after takeoff at different speeds and RPM every time.

 

UUHHHG

[life_on_venus]

7 hours ago, sdj64 said:

I have a new engine!  Incorporating some of the newest tech (physics-less vanes and inside out design) with the Stayputnik bearing, this engine is by far the best power bang for your part count buck so far.  Managing 40 of whatever drunken unit KER uses for RPM, it's a full 25% faster than the prototype Mk3 sized plane that tested the bearing design.  It's also my first engine that I've given a name to: the Bluebeam engine.

And, it's my first prop plane over 200 m/s!

 

Here is the engine without fairing in the VAB.  The shaft was shortened to one structural fuselage in length, reducing bending.

 

I am also putting all my successful turboprops on KerbalX for everyone to download and try out.  Most of them have the outermost ailerons always deployed to counteract roll from the prop.  You can adjust the authority limits of them while in flight to maintain level as you speed up or slow down.

Here's a link to the hangar:  https://kerbalx.com/hangars/9644

 

@life_on_venus Take a look at some of my designs.  Most of them are not quite as refined as the regulars on this thread, but they are consistently low in part count.

Ah thanks, I will do

hey, I notice that the designs you guys make have the engines arranged radially, pushing "sideways" onto flat turbine blades. I'm guessing this is to stop the shaft from being pushed forward/backward? Is there any reason not to arrange engines parallel the shaft, pointing towards angled turbine blades?

[Gman_builder]

25 minutes ago, life_on_venus said:

Ah thanks, I will do

hey, I notice that the designs you guys make have the engines arranged radially, pushing "sideways" onto flat turbine blades. I'm guessing this is to stop the shaft from being pushed forward/backward? Is there any reason not to arrange engines parallel the shaft, pointing towards angled turbine blades?

If you angle them backward you will have thrust provided from the blowers rather than the actual engine. If you angle them forward you will just have thrust from the blowers working to slow the plane down.

I am so mad. My game just s h I t itself today and my plane no longer works. I restarted my game and my PC several times to no avail.   

FUUUUUUUUUU

I guess I will just have to START OVER

why is this game the way it is

[Gman_builder]

I copied the exact craft over to my slower, grosser, desktop and it works flawlessly. Except for the extra lag. So I have no idea whats wrong with my laptop but I guess for the remainder of my tests of this plane I will be on my desktop.  

[Pds314]

2 hours ago, life_on_venus said:

Ah thanks, I will do

hey, I notice that the designs you guys make have the engines arranged radially, pushing "sideways" onto flat turbine blades. I'm guessing this is to stop the shaft from being pushed forward/backward? Is there any reason not to arrange engines parallel the shaft, pointing towards angled turbine blades?

Several reasons:

#1. Ksp physics is silly. The blowers always apply force in the direction of the pressure. You cannot generate "lift" by redirecting this thrust. If you push a wing with a thruster, it will push straight back against the thruster.

#2. If any thrust vectors point out into the atmosphere instead of into the prop, you will have unbalanced jet thrust, which is cheating, and also disruptive. It should be noted, however, that unbalanced jet thrust inside a closed space or pushing on the turbine blades is not a problem, as momentum is still conserved due to the equal and opposite force against the object being struck by the thrust vector. In other words, a 1x Juno engine wouldn't be cheating so long as the Juno is always pointed towards part of the same craft or its propeller shaft. Similarly, forward or backward-facing jets shouldn't be an issue in this respect.

The most significant issue with forward and backward jets is efficiency. A jet facing directly forward or backward cannot generate any torque. Even if it is pushing agains. A wing, the direction of force force will always be the direction of thrust and the magnitude of force will be the magnitude of thrust. It's not that you couldn't do this, just that it wouldn't be particularly helpful, and would reduce the power and efficiency of an engine. Considering that many small engines under <1.5 meters are already struggling in terms of power and all engines leave much to be desired in terms of efficiency, I cannot see any good reason to cant the engines more than, say, 10 degree off perpendicular. The only good reason I could think of, which I may actually use in a compact engine design at some point, is to improve the ratio of torque radius engine maximum radius, or to reduce the part count on certain types of engines.

Edited July 18, 2016 by Pds314

[Azimech]

11 hours ago, Pds314 said:

Hmm.. I've been thinking: is it ever sensible to use Panthers instead of Junos for their extra ISP?

The basic problem is size. Panthers are big, which, for a given engine radius, decreases the maximum torque radius, killing efficiency.

But they are also 40.6% more fuel efficient.

So if you can avoid reducing the torque radius by 29% or more, the panther is more fuel efficient, HOWEVER, with a reduced fuel torque radius, the engine is less powerful as well. I.e. an engine with 12 Panthers at a 1 meter torque radius is less powerful and heavier than a less fuel efficient engine with 48 Junos at a 1.2 meter radius.

 

Overall, if fuel efficiency is a concern, it appears Panthers are usually less efficient than Junos when extra mass required for power parity is considered.

EDIT: it's even worse than in my example. For a given outer radius and assuming the turbine blades are interior to the blowers, A Panther reduces the torque radius by an absolute minimum of about 1.25 meters, and very likely more, whilst a Juno reduces that radius by about 0.625, possibly a bit less due to their shape.

This means that a typical panther engine has a torque radius minimally 0.625 meters smaller than that of a Juno engine. I.E. A Panther-based Varpulis analogue would have a torque radius of something like 0.675 meters instead of like 1.3. Not only does that eliminate the efficiency advantage of the Panther, it eliminates the the afterburning power advantage as well. And to get the same power, you end up needing about 1 panther for every 2-3 Junos. Not good at all. Even if fuel efficiency is all that's under consideration, the minimum outer diameter at which Panthers are more efficient than Junos appears to be ~7 meters.

If I can convince Squad to give the basic jet engine (Wheesley) it's exhaust thrust back, it will be the best engine overall: same weight/power ratio as the Juno, excellent static thrust, excellent for part count (1 Wheesley =  6 Juno's).

[Pds314]

8 hours ago, Azimech said:

If I can convince Squad to give the basic jet engine (Wheesley) it's exhaust thrust back, it will be the best engine overall: same weight/power ratio as the Juno, excellent static thrust, excellent for part count (1 Wheesley =  6 Juno's).

It'll be good for part count, and above a certain size, fuel efficiency, but it will be worse for torque per weight at a given external diameter because it's wider and therefore reduces torque radius more. So, for example, an engine with a 5m external diameter that uses Junos could have a torque radius of up to 1.875 meters, while a same-size engine using Wheesleys would be limited to 1.25. That's a full 1/3rd reduction in torque and power, and a lot of ALL OF the efficiency advantage goes away to. Wheesleys are 50% more efficient, but Junos have a 50% better torque radius. One Wheesley is worth 4 Junos there, plus 0.5 tones of dead weight.

Edited July 18, 2016 by Pds314