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

[Azimech]

47 minutes ago, EpicSpaceTroll139 said:

Out of curiosity, have you tried one-piece turbines* using parts such as fairing bases? Like the Mk2 cores, they don't expand as their COM is in line with the shaft. Is the reason for the multiple turbine elements because they withstand heat better? I imagine heat tolerance might be a bigger issue for your helis as their lower turbine radius (1.25meterish) requires more thrust impinging on the turbine than my over-sized (1.88meterish) turbines for the same torque... I think... Correct me if I'm wrong.

*I've actually tried multi-part turbines, though the reason I've used them was for space saving reasons. For example on coaxial designs I can have a bearing for one rotor inside the turbine for the other

I look at a couple of things. Because with my big designs the turbine shaft is allowed to flex in its housing, collisions may occur with other parts during high speed or aerobatics. Fairing bases and heat shields can't take a lot.
Heat tolerance is secondary for me.

41 minutes ago, qzgy said:

I believe he has, using a heat shield for his new smaller turbine design.

@Azimech, correct me if I'm wrong\

 

Also, mind showing a picture of your coaxial design to me? I've been trying to make a coaxial thing for a while, haven't been able to get something small enough that's powerful enough...

Sure, no problem.

 

Wait for it ...

 

 

Little joke there. That "thing" is the first coaxial turboshaft in existence, made almost 2.5 years ago. I'm glad I've never released that one, it's fugly.

 

There are either two solutions. The one is complex, have one shaft rotate in another, the other is just offset hacking. I prefer the first but I know the limitations (size, mass, drag, part count).

Here you can find both:

https://kerbalx.com/Azimech/77I-Azi29-Janus-v10
https://kerbalx.com/Azimech/77-Industries---CTR3-10

Keep in mind the CTR3 doesn't run, it was built in 1.0.4.

Here's a video with a later variant:

Now I know you'd like a compact, offset hack style coaxial. I haven't really built one yet but when I do, I'll make it public.

It will probably be with a 2.5m heat shield instead of 1.25, the smaller ones are just way too inefficient.

Edited June 20, 2017 by Azimech

[EpicSpaceTroll139]

@qzgy Ah yes! I almost forgot! I noticed that a day or two ago when I tested out @Azimech's Apache prototype. On a funny note, I hope that those seats had some nice cushions. That thing was rattling around more than an unbalanced washing machine!  Looked cool though!

Also, figured I might as well show qzgy the mechanism on one of my own Coaxial helis.

I pulled the rotor blades and the housing off so that things are easier to see. I also labeled the components.

1. Lower rotor one-piece turbine; spins clockwise

2. Upper rotor multiple-part turbine element, joined at the upper turbine hub (2.5); spins counterclockwise

3. Blowers for lower turbine and (3.5) upper turbine

4. Lower rotor/turbine retention pin

5. Upper rotor/turbine retention pin

6. Lower rotor top bearing (another one is hidden inside the fuselage of the heli underneath) *

7. Upper rotor top bearing, uses an experimental quad octostrut bearing (once again another bearing is hidden below)  *

 

*I don't remember the exact reason why the top bearing for the lower one is above the top bearing for the upper one, but it must have been to keep something from exploding. 

 

Edited June 20, 2017 by EpicSpaceTroll139

[qzgy]

45 minutes ago, Azimech said:

Now I know you'd like a compact, offset hack style coaxial. I haven't really built one yet but when I do, I'll make it public.

It will probably be with a 2.5m heat shield instead of 1.25, the smaller ones are just way too inefficient.

Yeah, I've experimented with offset hacking for a "coaxial" rotor system.. Sorta worked, reliability was an issue and also making it fit into the model I wanted (that was actually the bigger problem.)

 

@EpicSpaceTroll139 Thanks! That's actually a really cool idea, using to turbine rotors stacked on top of each other like that. Why one multipart and the other one solid? I would guess it was for the lower retention pin, but I'm not sure.

[EpicSpaceTroll139]

1 minute ago, qzgy said:

<snip> Why one multipart and the other one solid? I would guess it was for the lower retention pin, but I'm not sure.

Indeed that was exactly the reason for the multipart turbine, although if I ever do a rebuild, I think I could move the retention pin to some other location and thus save on part count. Might even reduce drag too, not sure.

[Krog34]

Oh wise and great turboshaft masters, I've been having a problem with a design of mine and I'm a bit stumped. I hope this is the right place to post this!

You see, I've found myself in love with the coaxial copter, the Sikorsky S-97 Raider. So I've set out to make my own coaxial design. I've come to a crossroads however. I'm debating abandoning the design and trying something new but I'd like to see if anyone has input before I totally go back to the drawing board. The two rotors are on separate action groups for testing. The upper rotor can achieve full throttle no problem, while the lower is just not having any of it, only achieving 1/3 throttle stably. I've adjusted and tweaked just about everything but the weak link seems to be the structural fuselage every time.

 

IDK ¯\_(ツ)_/¯  let me know what you think....

[Azimech]

3 hours ago, Krog34 said:

Oh wise and great turboshaft masters, I've been having a problem with a design of mine and I'm a bit stumped. I hope this is the right place to post this!

You see, I've found myself in love with the coaxial copter, the Sikorsky S-97 Raider. So I've set out to make my own coaxial design. I've come to a crossroads however. I'm debating abandoning the design and trying something new but I'd like to see if anyone has input before I totally go back to the drawing board. The two rotors are on separate action groups for testing. The upper rotor can achieve full throttle no problem, while the lower is just not having any of it, only achieving 1/3 throttle stably. I've adjusted and tweaked just about everything but the weak link seems to be the structural fuselage every time.

 

IDK ¯\_(ツ)_/¯  let me know what you think....

I'm guessing the hollow fuselage you're using is being pushed beyond the 10 m/s impact rating. I understand completely why you'd want to use it, it's a very elegant solution.

[Jakalth]

Hay Azimech, it's been a long time since I chatted here.  Finally got back into trying to make vanilla turboshaft engines and fell into the now common problem of landing gear being a P.I.T.A....  So I did end up finally getting one turboshaft to work, all be it very inefficiently...  It has a hybred half landing gear half slide bearing design.  thought you might enjoy the novelty of looking at it.  1.3 copter test3

Barely flies, terribly inefficient and underpowered, but the turboshaft engine it's self seems somewhat solid...ish... 30 Junos as blowers.

 

The main reason I'm asking here is for some tips on the second turboshaft I'm working on.  It's part of a partially completed heli, which will be redone once the turboshaft engine is bug fixed.  The engine it's self has far more power then the other one and is lighter.  But it has a fatal flaw...  The top landing gear bearings...  The engine spins up nicely and has enough torque to spin the rotors at a good clip.  But when it gets close to full power, the shaft of the engine starts to hop and will eventually bounce with enough force to destroy the bearing wheels on the bottom of the engine.  This becomes a fatal problem quickly.

I can't quite find a solution to this bounciness problem, and I have tried several different tricks to reduce the landing gears recoil with no success.  The engine is stable enough laterally, but it's the vertical glitchiness that kills it... prototype turboshaft heli 1

The heli's body is temporary, I'll be making it look and work better once I can find a solution to the engine.

 

Got a prototype heavy turboshaft engine atm that weights in at a heavy 24.185 tons empty and is capable of lifting off with a 3/4 filled S3-7200 fuel tank, with 4 wheasleys for counter torque, weighing in at 32.6 tons, for a combined weight of 56.785tons.  Is that good, bad, average????  It's using a 6x symmetry rotor make from 5 "wing connector type E", and this one does not have the maniac shaking of the above model...  Uses 40 Junos as blowers.

 

Also, still looking for any tips I can get on how to stabilize a more compact turboshaft engine.  Trying to use the small stearable landing gear but getting a lot of rebound glitching which eventually leads to violent dissasembly.

Edited June 30, 2017 by Jakalth

[Azimech]

15 hours ago, Jakalth said:

Hay Azimech, it's been a long time since I chatted here.  Finally got back into trying to make vanilla turboshaft engines and fell into the now common problem of landing gear being a P.I.T.A....  So I did end up finally getting one turboshaft to work, all be it very inefficiently...  It has a hybred half landing gear half slide bearing design.  thought you might enjoy the novelty of looking at it.  1.3 copter test3

Barely flies, terribly inefficient and underpowered, but the turboshaft engine it's self seems somewhat solid...ish... 30 Junos as blowers.

 

The main reason I'm asking here is for some tips on the second turboshaft I'm working on.  It's part of a partially completed heli, which will be redone once the turboshaft engine is bug fixed.  The engine it's self has far more power then the other one and is lighter.  But it has a fatal flaw...  The top landing gear bearings...  The engine spins up nicely and has enough torque to spin the rotors at a good clip.  But when it gets close to full power, the shaft of the engine starts to hop and will eventually bounce with enough force to destroy the bearing wheels on the bottom of the engine.  This becomes a fatal problem quickly.

I can't quite find a solution to this bounciness problem, and I have tried several different tricks to reduce the landing gears recoil with no success.  The engine is stable enough laterally, but it's the vertical glitchiness that kills it... prototype turboshaft heli 1

The heli's body is temporary, I'll be making it look and work better once I can find a solution to the engine.

 

Got a prototype heavy turboshaft engine atm that weights in at a heavy 24.185 tons empty and is capable of lifting off with a 3/4 filled S3-7200 fuel tank, with 4 wheasleys for counter torque, weighing in at 32.6 tons, for a combined weight of 56.785tons.  Is that good, bad, average????  It's using a 6x symmetry rotor make from 5 "wing connector type E", and this one does not have the maniac shaking of the above model...  Uses 40 Junos as blowers.

 

Also, still looking for any tips I can get on how to stabilize a more compact turboshaft engine.  Trying to use the small stearable landing gear but getting a lot of rebound glitching which eventually leads to violent dissasembly.

 

I'll take a look when I get home. Gotta run.

 

[Jakalth]

Well, I did figure out most of the issues with the second helicopter.  They involved not using the Completely broken and useless small steerable landing gear and replacing them with the much larger small stow able landing gear.  Not ideal due to size difference, but made the turbine stable enough for flight.  Not it's simply a matter of me not being very good at making helicopters...  :\

But on a different note: I've done some testing and got a heavy turboshaft working.  One that's capable of lifting a 60 ton craft into the air.  Sadly the design is only usable if you don't make any kind of maneuvers other then just flying strait up...  Any maneuvers at all and it spontaneously disassembles...

But I do have one success, even if it's not complete, I have a working duel output turboshaft.  This turboshaft can spin a set of rotors on both ends of the engine, not just the one end.  It seems to handle some pretty high rpm's as well.  Don't have VOID installed, and keep forgetting to install it, so don't have exact numbers.  But testing shows it's more then capable of lifting its own weight, and then some, with only basic 6x symmetry rotors.  I'm not sure yet what advantages this setup might have, but so far it doesn't seem to have as much of an issue with the rotation of the rotors causing the craft to tip to one side.  Of course, being one of my designs, it's not entirely stable yet and the turbine tends to pull it's self free from the bearings when subjected to lateral forces. aka: tilting

[Jakalth]

Alright.  Got one for you guys to try out.  This is easily my best turboshaft engine.  Works extremely well, and only uses 8 Juno's as blowers.  It is very much a lite duty turboshaft atm but I'm sure it's total power could be ramped up immensely just by adding more blowers.  The engine it's self is stable, can handle some rough maneuvers now, and no longer freaks out when being tilted.  The platform it is mounted to allows the turbine to be flown, and it flies surprisingly well.  The craft is almost stable enough to be flown without using sas.  Still has a slight torque indifference though.  This craft is just a flying test bed for the turboshaft engine.  Meduim turbine 1 aka: flying twin rotor testbed.

 

 

Staging is setup, but ejecting the stack separator to free the turbine is a bit glitchy.  Make sure the separator is completely free of the turbine housing before staging to the engines.  The separator tends to not cooperate and likes to wedge its self inside the turbine housing.  If this happens, simple retract the landing gear and let the turbine drop to the ground.  Once the separator is free, extend the landing gear to pick the turbine back up again.  The turbine is close enough to the ground for this to work.

Second stage simply starts the engines and releases the docking clamps, whos job is simply to prevent the whole craft from being launched by the glitchy separator.

Also, the controls are a bit odd. w/s pitches up/down, a/d rolls left/right, and q/e turns right/left.  This is due to the oddly placed drone core.  But don't worry, this craft can be recovered from odd angles fairly easily.

As a last note, this craft has no fuel so requires infinite propellant.  Once this turboshaft design is perfected with better bearings, better rotors, and better/more blowers, it should have more then enough power to lift the fuel it needs.

Edited July 3, 2017 by Jakalth

[EpicSpaceTroll139]

@Jakalth I read that you were trying to make compact bearings using the small steerable heels and weren't having much luck. Might I suggest antenna + solar panel bearings? They basically amount to a small disk made of static solar panels attached to the fuselage/motor mount with an antenna attached to the rotor riding inside a hole in the disk. You put one below the turbine and one above the rotor, and add something to keep it from pulling up and out, and it's good to go. I don't have any pics at the moment, buy here's a craft which demonstrates them.

https://kerbalx.com/EpicSpaceTroll139/E-24A-Champion

In certain conditions they may not be as tough as shed sized wheeled bearings, but they're quite light and compact, and so far I've managed to go up to payloads of 135 tons.

Nice work BTW!

[MiffedStarfish]

Finally built a working turboprop, now to mount it on something...

[EpicSpaceTroll139]

Ok so I've created a kOS script that will keep an otherwise stock propeller or rotor running at a roughly constant rpm, and multiples of it can be running at the same time so it can be used to run 8 propellers just as well as it can run 1. It uses a PID loop to control the deflection of the blades, keeping the ride smooth, although the PID loop might be able to be tuned a bit better (although I didn't see any problems resulting from it not being tuned).

Demonstration pics here using letmeparkthatforyou's Kermansky K-1200:

Full dry throttle (wet works too), about 140rpm

12% dry power, still about 140 rpm

 

It can give somewhat quicker response time on regular stock helis, but where I see it being most useful for now is in turboprop planes and tiltrotors. (@klond you might want to try it on the mini tiltrotor if you can fit a solar panel or something on the prop.) It could also become useful on helicopters if I can complete my cyclic script, as it would probably benefit from a restrained rotor speed.

 

I need to find a hosting site for posting the script in a more convenient manner, but for now I'll just put it in here:

Spoiler

//This script keeps a propeller or rotor spinning at a target rate

Set Targ_RPM to 140.    Set Targ_Ang_Vel to (Targ_RPM/30)*constant:pi. //Use if you want to set rotor speed in revolutions per minute

//Set Targ_Ang_Vel to <insert number here> //Use if you want to set rotor speed in radians per second

Lock Ang_Vel to abs(ship:angularvel*ship:facing:forevector). //gets spin rate of rotor, taking out wobble
Lock P to (Ang_Vel - Targ_Ang_Vel). //Difference between actual spin rate and target spin rate
Set I to 0. //Temporarily defined as zero, will be total difference over time
Set D to 0. //Temporarily defined as zero, will be angular acceleration of rotor

//PID loop component coefficients, need to be tuned at some point, probably vehicle specific
Set kP to 10. //Coefficient for Proportional value
Set kI to 1. //Coefficient for Integral value
Set kD to 10. //Coefficient for Derivative value

Set deflection to 10. //Temporarily defined as 10
Lock d_deflection to kP*P + kI*I + kD*D. //defines change in deflection of blades

Set T0 to time:seconds. //Sets T0 to time:seconds at beginning of the loop
Set P0 to 1. //Temporarily sets P0 to 1. Might be able to set it to 0. Needs testing.

Until (Abort)
{
    Clearscreen.
    Set dt to time:seconds - T0.
    If (dt > 0)
    {
        Set I to I + P*dt.
        Set D to (P - P0) / dt.

        //Blade deflector loop
        If (deflection + d_deflection < -150)    //Keeps blade pitch from going out of bounds negative
        {
            Set deflection to -150.
        }
        Else
        {
            If (deflection + d_deflection > 150)    //Keeps blade pitch from going out of bounds positive
            {
                Set deflection to 150.
            }
            Else
            {
                Set deflection to deflection + d_deflection.
            }.
        }.
        
        
        For Blade in ship:partsdubbed("Blade")    //Performs actual pitch manipulation
        {
            Blade:getmodule("ModuleControlSurface"):setfield("Authority Limiter", deflection).
        }.
        

        Print round(Ang_Vel/constant:pi*30) + "rpm (" + round(Ang_Vel) + "rad/sec)".
        
        
        Set P0 to P.
    }.
    Set T0 to time:seconds.
    Wait 0.001. 
}.

Instructions:

1. Install kOS and put the above script in the Ships-->Script folder of your game as a text file.

2. Make sure that the prop/rotor shaft has a probe core, kOS computer (or edit the probe core to be a kOS computer as I did), and power source.

3. Set blades so that when deployed and at full -150 authority limiter they are flat, or just as flat as you ever expect to need them, and set their nametags to "Blade". (You could also set them at 150 as steep as you expect to need them, better for planes)

4. Edit the Targ_RPM or Targ_Ang_Vel in the first few lines to whatever you think works best for you. Save.

5. Start up your plane normally, and run the script by opening the kOS window and performing the following steps:

"Switch to 0." *Enter*

"Run <insert what you named the file here>.txt." *Enter*

You can now minimize or close the kOS window if you want, I like keeping it open just to see how closely it is keeping the target rpm.

 

Try it if you want, and let me know what you think

 

Edit: I'm thinking I might try to add a function by which pressing "i" the deflection of the blades will be inverted, allowing inverted helicopter flight, which could be pretty funny.

Edited July 15, 2017 by EpicSpaceTroll139

[qzgy]

5 hours ago, EpicSpaceTroll139 said:

I need to find a hosting site for posting the script in a more convenient manner,

Pastebin?

[selfish_meme]

7 hours ago, EpicSpaceTroll139 said:

I need to find a hosting site for posting the script in a more convenient manner, but for now I'll just put it in here:

Or github

 

What advantage would a turboprop gain?

Does it only increase deflection?

Could it be set to maintain speed?

Edited July 15, 2017 by selfish_meme

[EpicSpaceTroll139]

1 minute ago, selfish_meme said:

Or github

 

What advantage would a turboprop gain?

Does it only increase deflection?

For the turboprop you would no longer need to monitor the rpm of the prop and adjust the propeller pitch manually. Some people's designs don't need this anyways, but on high power designs like @Azimech's, the same blade pitch that allows reasonable acceleration for takeoff would result in the prop over-speeding and the engine destroying itself during cruise.

It can both increase and decrease deflection.

I'll take a look at pastebin and GitHub

[qzgy]

Just now, EpicSpaceTroll139 said:

I'll take a look at pastebin and GitHub

Git hub is probably nicer. Pastebin is a copy and paste site.

[EpicSpaceTroll139]

I was just thinking it would be funny to lock the angular velocity to the frame rate so as to get that funny stroboscopic effect that makes it look like the rotor is standing still while flying.

In other news: the cyclic script is almost finished, and I'm hoping to test it tomorrow. I really hope physics tics are frequent enough to allow control surfaces to complete cycles within a single revolution of a rotor, otherwise I will have spent all this effort just to make a helicopter shake and break.

[selfish_meme]

2 minutes ago, EpicSpaceTroll139 said:

I was just thinking it would be funny to lock the angular velocity to the frame rate so as to get that funny stroboscopic effect that makes it look like the rotor is standing still while flying.

In other news: the cyclic script is almost finished, and I'm hoping to test it tomorrow. I really hope physics tics are frequent enough to allow control surfaces to complete cycles within a single revolution of a rotor, otherwise I will have spent all this effort just to make a helicopter shake and break.

or a harmonic of the frame rate so you get a nicely smoothed animation

[qzgy]

1 hour ago, EpicSpaceTroll139 said:

I was just thinking it would be funny to lock the angular velocity to the frame rate so as to get that funny stroboscopic effect that makes it look like the rotor is standing still while flying.

Do that.... I wanna see it.

[Azimech]

5 hours ago, EpicSpaceTroll139 said:

I was just thinking it would be funny to lock the angular velocity to the frame rate so as to get that funny stroboscopic effect that makes it look like the rotor is standing still while flying.

In other news: the cyclic script is almost finished, and I'm hoping to test it tomorrow. I really hope physics tics are frequent enough to allow control surfaces to complete cycles within a single revolution of a rotor, otherwise I will have spent all this effort just to make a helicopter shake and break.

I have news for you, you don't have to.

The thing you want is the PhysicalTimeRatioViewer, it lets you adjust the physics delta-t during flight.

And ... great work on that kOS script! I once tried to learn that stuff when I needed a signal for my piston engines but didn't feel I got much help from the community back then. Me and learning a programming language ... that's always been a problem unfortunately.

 

[selfish_meme]

5 hours ago, EpicSpaceTroll139 said:

I was just thinking it would be funny to lock the angular velocity to the frame rate so as to get that funny stroboscopic effect that makes it look like the rotor is standing still while flying.

In other news: the cyclic script is almost finished, and I'm hoping to test it tomorrow. I really hope physics tics are frequent enough to allow control surfaces to complete cycles within a single revolution of a rotor, otherwise I will have spent all this effort just to make a helicopter shake and break.

You know what would be really useful of course is throttle or trim control (for electric motors) for mutliengine craft.

[EpicSpaceTroll139]

@Azimech I'll have to check that mod out. 

I tried using the Time Control mod once to slow down time to find flaws in my helicopters, but it just made them instantly explode as soon I moved the slider.

@selfish_meme So the throttle controls the trim/power of the reaction wheels? Shouldn't be too hard to do. I'll take a look at it.

[Reusables]

Worked on turboprops, got these with great fun! Thanks, especially to @Majorjim! (and @klond ) for the RCS-Thermometer hinges!

http://imgur.com/a/wsL4O

Since I'm too into the performance of these engines to resist putting all the effort on optimizing the engine, I tried to maximize its TWR output. Here's TWR 7~8 in action. (Looks a bit wierd)

Here are 8 juno engines lifting 35t. Engine section weighs 4.73t excluding the mk3 cargo bay. Think I can say tgat the effective ISP is 14000.

Currently fabricating something actually useful out of this engine. Not going to be completed soon for no time is allowed for me to work with this simulator.

Edited July 20, 2017 by Reusables
Didn't know about where it is from.

[klond]

On 7/28/2016 at 3:39 PM, Gman_builder said:

I think a ornithopter would work similar to this. With a turboshaft engine geared up to the wings to do the flapping.

 It has begun...

 

 

 well, a demo anyways - don't get your hopes too high.  It'll probably end up as a jet that flaps but let's give it a go.

 I'm gonna need a dozen RCS balls and about 100 thermometers to get this party started.