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

[EpicSpaceTroll139]

1 hour ago, Azimech said:

@EpicSpaceTroll139 No DLC parts? If not I'll take a look.

I actually purposely avoided the use of DLC parts on this. I figure for the builds that take a lot of work like these helicopters, engines, and other mechanical contraptions and such, I want them to be as accessible to as many KSP players as possible.

I might however make a Soyuz like craft or something soon using the DLC parts.

Anyways, here's the joint thing:

https://kerbalx.com/EpicSpaceTroll139/Prototype-Tiltrotor-shaft-joint

[Azimech]

Cool! I'll take a look.

Meanwhile ...

Is this phase one of a helicarrier?

[EpicSpaceTroll139]

I remember there was once when I started working on a S.H.I.E.L.D. helicarrier replica as part of my oddball 5/6ths scale series... I recall I abandoned it because I couldn't get the kraken out of the helirotor things with their 20 blades or whatever it was. Not to mention I realized it would fly like... Well...an aircraft carrier, at something like 620m long or something like that.

I really should do more in that series lol.

 

Anyways, out of curiosity, how does that thing handle?

Edited March 31, 2018 by EpicSpaceTroll139

[Azimech]

44 minutes ago, EpicSpaceTroll139 said:

I remember there was once when I started working on a S.H.I.E.L.D. helicarrier replica as part of my oddball 5/6ths scale series... I recall I abandoned it because I couldn't get the kraken out of the helirotor things with their 20 blades or whatever it was. Not to mention I realized it would fly like... Well...an aircraft carrier, at something like 620m long or something like that.

I really should do more in that series lol.

 

Anyways, out of curiosity, how does that thing handle?

Pretty good!

I think it's almost finished.

Until now no funny things like RUDs.

Specs:

Mass: 474t.
Part count: 658.
Forward speed: >90m/s.
With 9000 units fuel remaining: 100m/s.

With enough forward speed, it almost handles like a Cessna :-)

Edited March 31, 2018 by Azimech

[jfrouleau]

@EpicSpaceTroll139 I checked your craft on KerbalX because I have experience with klaws and it looks like its something I can help with. What I found is that only 1 of the 2 klaws actually flex (not always the same one) which is I think the source of the friction. Here I just changed the staging and that solved the problem. Both klaws are flexing and the rotation speed stays the same no matter the angle (till you reach the klaw max angle). When assembling a craft with klaws, the docking sequence is important and have an impact on the structure of the resulting craft. This is why I usually decouple and dock each component separately (multiple staging) to guarantee the docking sequence. My method is the following: I start with the outermost component and make my way to the center so that you don't dock a component which is "sandwiched" between 2 parts. In this case you start with the component at the left of the leftmost klaw (see picture). Then you dock the component with the leftmost klaw, then the one with the rightmost klaw, and so on...

Also for what I know the klaw has a maximum flex angle of about 30 degrees on each side which gives a total amplitude of 60 degrees. Reading my notes, it looks like you even can dock a craft with itself using a klaw. I made this test once. This is quite surprising knowing that KSP represent crafts with a tree structure. I also found that using a rotating joint with klaw seems to limit the rotation speed like if the klaw had a maximum flex speed which limit the rotor performance. You could probably improve the performance by moving the turbine wheel / blower after the klaw joint so that the klaw just flex and don't rotate. The turbine wheel would rotate on the same axis as the propeller.

Btw this is a very good idea you had ! I'm looking forward to see a craft using this mechanism of tilt rotor. I wish it works. Maybe a similar technique could be used to make a thrust vectoring wheesley actuated by ailerons or a 30 degrees gimbaled LV-T30 for a lower tech / lower cost space shuttle.

[EpicSpaceTroll139]

4 hours ago, jfrouleau said:

<snip>

Btw this is a very good idea you had ! I'm looking forward to see a craft using this mechanism of tilt rotor. I wish it works. Maybe a similar technique could be used to make a thrust vectoring wheesley actuated by ailerons or a 30 degrees gimbaled LV-T30 for a lower tech / lower cost space shuttle.

Hmm... I tried setting up staging the way you recommended, but I'm still getting the same results. I mean, both claws bend, but one bends a lot more than the other, and when it reaches its limit it causes problems.

Since you mentioned there seems to be a rotation speed limit when using them, I'm going to try what you suggested and put the motor itself on a claw hinge, and have a rigid propshaft. I think that should make the thing more capable of heavy lift anyways, because with the bending shaft I found that one end of the shaft has to be able to slide axially in the bearings to some degree, which means that there would be a lot of side-loading in the bearings when in vertical-lift mode.

Edit: Also, now that you mention it, this could be great for space shuttles. Not only would it allow lower cost, high gimbal engines based on the LV-T30 or such, it could also be applied to large engines such as the Mainsail, allowing even larger shuttles to be less tedious to launch. No need to fiddle with thrust limiter or such on the way up.

Edit2: It would seem engines cannot draw fuel through claws, so it looks like I'm back to the bendable propshaft.

Edited March 31, 2018 by EpicSpaceTroll139

[Azimech]

The Vapula RS (Reduced Size). Cuts the length of the Vapula almost in half, has a stronger bearing (aft bearing has 12 elements instead of 8) and can't carry its own fuel.
It's also a lot more draggy though. Perfect for VTOLs but less ideal for airplanes.

 

And this is the Vapula MRS (More Reduced Size). This is an interesting one. 

 

What you see in the central shaft are two LY-60's rotated 180 degrees and lined up with the shaft. Due to the mass offset - which might still be solved - the shaft gets a dynamic unbalance around its central point.

The result is massive power loss but it still outputs a reasonably stable 950kN at 25 rad/s. Above that speed the values can go as high as 1250kN but jump all over the place. At this moment the construction is best for low speed applications but here comes the good news.

I've discovered I can do a test of its capabilities. First I let it run to max speed and then suddenly I change the prop pitch to max. While the shaft is slowing down I can get a very short glimpse of what kind of thrust it can withstand. And I've seen values of 4500kN!
So if you're in need of a gigantic bearing for low speed applications like building a mining dump truck, this is what you'll have to build.

 

 

 

[Azimech]

Ahem. I've discovered I had KJR installed. This means the bearing and/or engine in the previous post is less powerful than 4500kN. It's more like 2500kN. Still impressive though.

[qzgy]

3 hours ago, Azimech said:

Due to the mass offset - which might still be solved

Not sure if you tried this already but I wonder what happens if you radially attach 2 landing gear and clip them together to act as one collider so the mass offset is canceled by just having two landing gear on the shaft. So you would end up with more landing gear in the shaft as you would need 2 per side of the shaft so like 4 in total. If that makes any sense.

 

Looks neat though.

[EpicSpaceTroll139]

56 minutes ago, Azimech said:

Ahem. I've discovered I had KJR installed. This means the bearing and/or engine in the previous post is less powerful than 4500kN. It's more like 2500kN. Still impressive though.

 

45 minutes ago, qzgy said:

Not sure if you tried this already but I wonder what happens if you radially attach 2 landing gear and clip them together to act as one collider so the mass offset is canceled by just having two landing gear on the shaft. So you would end up with more landing gear in the shaft as you would need 2 per side of the shaft so like 4 in total. If that makes any sense. <snip>

While I remember realizing after I suggested the same thing that you said it didn't work, I wonder, if KJR was installed when you first tested it, could that have been causing the problems?

Maybe clipped landing gear work ok without KJR?

Also... what if you inverted the bearing? Attached the spindle to the airframe and the radial gear to the propeller? I know that didn't work for my solar panel bearings, but maybe it would work for these larger bearings?

[Azimech]

2 minutes ago, EpicSpaceTroll139 said:

 

While I remember realizing after I suggested the same thing that you said it didn't work, I wonder, if KJR was installed when you first tested it, could that have been causing the problems?

Maybe clipped landing gear work ok without KJR?

 

I could try again with them clipped.

 

Quote

Also... what if you inverted the bearing? Attached the spindle to the airframe and the radial gear to the propeller? I know that didn't work for my solar panel bearings, but maybe it would work for these larger bearings?

That's a neat idea! Unfortunately that increases the drag and rotating mass with a huge amount. Not only that, I'm pretty sure landing gear don't add their mass to their parent part - in other words they expand with high revs.

Other news: Azi-30 Taranis has a new turbine shaft. Gone are the vibrations, the heli is now 4 tons lighter and it shows: climb rate went up from 3 to 4m/s.

Unfortunately I had to ditch the Wheesley since it's now blocked. Replaced with two Juno's in the back.

[jfrouleau]

@EpicSpaceTroll139  I retested the flexible shaft this morning and it looks like you're right. The thing was already flexing the same way before I changed the staging. I probably just forgot to free one klaw the first time I tested it like an idiot. Still it bends to about 60 degrees for 2 klaws which is what I expect it to do before problems occur. For 90 degrees you would need 3 klaws like my synchropter use on each side. I verified for the fuel crossfeed and indeed the klaw doesn't have fuel crossfeed which makes me sad  So yeah... back to the first idea unless you also put the fuel tank on that last part of the articulation with the engine. Sorry I couldn't help more.

[EpicSpaceTroll139]

27 minutes ago, jfrouleau said:

@EpicSpaceTroll139  I retested the flexible shaft this morning and it looks like you're right. The thing was already flexing the same way before I changed the staging. I probably just forgot to free one klaw the first time I tested it like an idiot. Still it bends to about 60 degrees for 2 klaws which is what I expect it to do before problems occur. For 90 degrees you would need 3 klaws like my synchropter use on each side. I verified for the fuel crossfeed and indeed the klaw doesn't have fuel crossfeed which makes me sad  So yeah... back to the first idea unless you also put the fuel tank on that last part of the articulation with the engine. Sorry I couldn't help more.

Yah you're right. It does look like it is bending a total of around 60 degrees or so. Maybe my brain is tricking me that one looks like it's bending less than the other.

Definitely going to try putting 3 claws to get 90 degrees.

The main reason I don't want to put tanks on the ends of the claws because it means one would have to regularly transfer fuel to them which could get annoying. Ah well

[qzgy]

2 minutes ago, EpicSpaceTroll139 said:

The main reason I don't want to put tanks on the ends of the claws because it means one would have to regularly transfer fuel to them which could get annoying. Ah well

Not sure your opinion on mod based solutions, but TAC fuel balancer can auto transfer fuel in/out of tanks (continuously pump fuel). So maybe that might work? Unless I'm miss understanding something.

Edited April 1, 2018 by qzgy

[jfrouleau]

@EpicSpaceTroll139  I posted something for you on KerbalX that might interest you. Flexible joint with fuel crossfeed
https://kerbalx.com/jfrouleau/LV-T30-Gimbal-Test

[Rakaydos]

I built my first rotor, based on a microbearing I got as a craft file, 2 small reaction wheels and 6 blades. It lifts 2 tons (including itself).

Is there an optimum blade/reaction wheel ratio?

[Azimech]

11 hours ago, Rakaydos said:

I built my first rotor, based on a microbearing I got as a craft file, 2 small reaction wheels and 6 blades. It lifts 2 tons (including itself).

Is there an optimum blade/reaction wheel ratio?

Sorry, wrong topic. There's a topic specific for electro-motors over here:

This topic is for turboprop/turboshaft engines or derivatives.

[selfish_meme]

I opened up an old craft thinking about making a screenshot and took it for a quick fly to see if it still worked. Amazingly it did, I also found out I was halfway through modifying a bearing. The new bearing was quite a bit better than the old one. It seems to be very reliable and durable (unfortunately no faster) So I finished off the plane and posted it. I think the bearing may take a bit more torque than my old RCS ball bearings, I will check it out, if so I might get this Dornier Do335 a bit faster. It's already a very stable and easy to fly plane with no torque issues, it would be good if it was a touch faster.

Download

Edited April 8, 2018 by selfish_meme

[Azimech]

1 hour ago, selfish_meme said:

I opened up an old craft thinking about making a screenshot and took it for a quick fly to see if it still worked. Amazingly it did, I also found out I was halfway through modifying a bearing. The new bearing was quite a bit better than the old one. It seems to be very reliable and durable (unfortunately no faster) So I finished off the plane and posted it. I think the bearing may take a bit more torque than my old RCS ball bearings, I will check it out, if so I might get this Dornier Do335 a bit faster. It's already a very stable and easy to fly plane with no torque issues, it would be good if it was a touch faster.

Download

I see you're using the tiny wings as blades ... not being able to change your prop pitch isn't really going to help with achieving a better speed, unfortunately.

[selfish_meme]

2 hours ago, Azimech said:

I see you're using the tiny wings as blades ... not being able to change your prop pitch isn't really going to help with achieving a better speed, unfortunately.

It seems to make no difference to top end speed, I had elevons on there before, but it may just be little adjustments, plus these give me a bit more wiggle room on takeoff

Edited April 9, 2018 by selfish_meme

[selfish_meme]

I updated the DO 335 and it is now a 70ms+ 4 Juno plane with extended range, aerobatic ability and more accurate looks KerbalX

I was getting frustrated with 1.25m fairings, they just didn't do what I expected them too, so I switched to the new structural tube and voila, my new 1.25m engine, I think my 4 engine plane might make 100ms with this new engine (Note: the engine is aerobatic, the plane is not  )

[Azimech]

Link to post elsewhere ... you guys might like this.

 

[klond]

 How is lift or pull calculated on turboprops here?  Sometimes I see xxx kilo Newtons for power listed but unsure how that number is derived.

[Azimech]

1 minute ago, klond said:

 How is lift or pull calculated on turboprops here?  Sometimes I see xxx kilo Newtons for power listed but unsure how that number is derived.

Switch on the aero info in the context menu (Alt-F12, physics->aero tab). Choose a propeller blade and change focus to it. Pin the context menu. Return to the main craft. Now multiply the lift value with the number of blades. Since the values are usually jumping around, I tend to hit Esc a lot to pause, then after reading a lot of values I note an average.

[KerrMü]

Hi folks

First: I haven´t built any turboprops for almost a year (Imgur says 11 months), so I don´t know if anything of this is new or even a little bit exiting. But I´d like to get back into stock propeller crafts, and helicopters are always fun and lot´s of hours to tinker with. So here is my first project and in general my first helicopter that is actually not quite bad.

This is where I stopped yesterday evening:

Fixed rotorhead heli. It could hover and land pretty accurately as you can see, and I liked the looks. But flying forward? Not so much. It was semi stable up to 25m/s, but very hard to control. past that point it rolled left and went out of control.

So when I went to bed I knew, if I wanted to improve it, I´d need a new rotorhead to at least in part neutralize the loss of lift by the backward moving blades. (sorry, not a native english speaker, no plan what the special terms might be) So, a rotorhead that allows individual blade pitch, self regulating and not toooo hard on the bearings... ouch. 

Recently I watched luizopilotos exellent and amazing video with his Hue-64 Skycrane using advanced grabbing units as blade pivot points. I downloaded his craft but couldn´t fly it. (every time I tried, one of the blades didn´t connect) So I built my own version and changed the angles on the claws a little bit.

Surprisingly it kinda works. Here is a pic of it in motion. The helicopter is descending at this point with very little thrust. The angles are usually not that extreme.

So this design gets up to 50m/s in level flight with 10° nose pitch. Could it go faster? No idea. haven´t tried yet.

How stable is it? Well, today I flew to the Island Airfield and back, and my longest testflight took 30 minutes until something collided with something.

I´ll certainly play around with it some more, but for the next 2 days I´ll be out of town, and I wanted to post this tonight, because I´m already pretty happy with it. Again, if this is all old, boring stuff, I´m sorry.

Here is the craftfile if you want to give it a try. Any suggestion on how to improve this craft are more than welcome.

https://kerbalx.com/herrmue/Mus-HC-5-Mk-52

Standard helicopter controls.

Hit space to attach the blades to the rotor head. Action group 2 for switching control over to probe core 1 for horizontal flight. SAS on radial out. AG 3 for 5° nose pitch, AG 4 for 10°s. Control course with Q and E and by adjusting the angle of the rudder. You know the deal

About 70% of thrust is enough to take off. Funny thing: The higher you fly, the less thrust you need. To be honest, I was surprised how little thrust was needed at 4000 meters. It got to the point, where the Junos didn´t produce enough electricity to power the SAS modules. That´s why I put a fuelcell on the latest build, but I didn´t have time to test it yet.

That´s it for now, have fun

Cheers, Mü