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

[Jon144]

 

2 minutes ago, EpicSpaceTroll139 said:

You actually don't need mods to tell rpm. If you open the alt+f12 menu, click the physics then aero tab, and click display, you will get a whole bunch of stats. Switch to the rotor and it will give you it's "roll" ---> spin rate in degrees per second

I have looked there before but in experience those don't seem accurate because those numbers have a certain cap that they max out at that does not actually represent the accurate values.

Also I would like to see what the rads are for those bearings in stationary flight at full throttle compared to what they would be like in forward flight at the helicopter's 40 M/S cruising speed.

Edited August 9, 2016 by Jon144

[Gman_builder]

Just now, EpicSpaceTroll139 said:

You actually don't need mods to tell rpm. If you open the alt+f12 menu, click the physics then aero tab, and click display, you will get a whole bunch of stats. Switch to the rotor and it will give you it's "roll" ---> spin rate in degrees per second

Oh yeah forgot about that.

[EpicSpaceTroll139]

Well there is an angular velocity limit coded into the physics.cfg that, unedited, hard limits the spin of vessel and thus rotor to 31.4159 radians per second. My guess is this is what you are running into and that your blades simply aren't going faster. I know that the display works above the stock angular velocity settings, so I doubt you found a true inaccuracy.

Is your cap 1800deg/sec?

Edited August 9, 2016 by EpicSpaceTroll139

[Jon144]

2 minutes ago, EpicSpaceTroll139 said:

Well there is an angular velocity limit coded into the physics.cfg that, unedited, hard limits the spin of vessel and thus rotor to 31.something radians per second. My guess is this is what you are running into and that your blades simply aren't going faster. I know that the display works above the stock angular velocity settings, so I doubt you found a true inaccuracy.

Right. This was a long time ago. Like several game versions ago I think. I'll have to give it another shot and see.

[EpicSpaceTroll139]

1 minute ago, Jon144 said:

Is your cap 1800deg/s? Bcc I just calculated that is the regular stock limit

[Jon144]

Wow. Some of these stats are more impressive than I expected. So it is confirmed using a helicopter like this is actually more efficient than just making a traditional VTOL with upwards facing jets. For 50kN of thrust creates over 200kN of force. Found on average the roll varies from 1100 to 1300.

Edited August 9, 2016 by Jon144

[EpicSpaceTroll139]

Thanks for going to the trouble of figuring that out!  I guess my rotors are flinging themselves apart because they're shorter, allowing them to spin quite a bit faster. With tip jets added, the stresses are just too much. Maybe tip jets are better for large helicopters. 

[Jon144]

1 hour ago, EpicSpaceTroll139 said:

Thanks for going to the trouble of figuring that out!  I guess my rotors are flinging themselves apart because they're shorter, allowing them to spin quite a bit faster. With tip jets added, the stresses are just too much. Maybe tip jets are better for large helicopters. 

You could try increasing the pitch of the rotor blades to slow them down and increase lift if they destroy themselves before reaching max speed anyways. Sounds more like a bearing deficiency. could you post a screenshot so I might help you?

You could try using an engine setup like this if having them at the very tips are just too much. I use this setup on my super-small new helicopter. It's actually quite reliable for a single rotor helicopter and might share it later.

If it is one of the thermometer hinge bearing'd helicopters you use that's probably the issue. As engine-tipped rotors require more reliable and sturdy bearings like pictured below. 

Edited August 9, 2016 by Jon144

[Majorjim!]

On 8 August 2016 at 2:01 AM, Gman_builder said:

electric bearings 

It sound like he's experiencing the blades pulling away under fast rotation rather than bearing failure. 

 What he cleverly did is stack my thermo bearings on top of each other which seems to give the main rotor shaft a lot of strength. Yes it uses more parts but you cannot make a smaller hinge. As I like to repeat. ;-)

[Ozin]

Do you guys prefer avoiding using mods such as Kerbal Joint Reinforcement? It helps a lot with keeping blades and other radially attached parts in place under high rotation.

[Gman_builder]

Ya we don't use KJR. It can actually cause performance limitations if combined with the right mods. As I have found.

[EpicSpaceTroll139]

39 minutes ago, Majorjim! said:

It sound like he's experiencing the blades pulling away under fast rotation rather than bearing failure. 

 What he cleverly did is stack my thermo bearings on top of each other which seems to give the main rotor shaft a lot of strength. Yes it uses more parts but you cannot make a smaller hinge. As I like to repeat. ;-)

Bingo! I attached tip jets to the blades of the traditional heli posted earlier. As the rotor spins up, it begins to expand, and eventually shatters before the heli has enough lift to take off. Half the time, the hub is left spinning in the middle. Without the tip jets it works fine.

As for the bearing, it actually uses a sort of "upgraded" version of the thermometer hinge. Instead of using thermometers in a tube, it has a disk of the small static solar panels. The core antenna is the same however. This hinge isn't quite as small, but it is much stronger. I think it has to do with the distance the antenna would have to clip to get outside the tube/disk.n

Edited August 9, 2016 by EpicSpaceTroll139

[Jon144]

2 hours ago, Majorjim! said:

It sound like he's experiencing the blades pulling away under fast rotation rather than bearing failure. 

 What he cleverly did is stack my thermo bearings on top of each other which seems to give the main rotor shaft a lot of strength. Yes it uses more parts but you cannot make a smaller hinge. As I like to repeat. ;-)

Well as you see the blades pull away on every helicopter I have ever made and especially so with the Chinook. It's just a matter of building the bearing and rotor strong enough. The blades pulling away from themselves is normal on any stock prop. You can always try adding more struts. But it sounds like your rotor and bearing are just too small. struts struts struts

Edited August 9, 2016 by Jon144

[EpicSpaceTroll139]

1 hour ago, Jon144 said:

Well as you see the blades pull away on every helicopter I have ever made and especially so with the Chinook. It's just a matter of building the bearing and rotor strong enough. The blades pulling away from themselves is normal on any stock prop. You can always try adding more struts. But it sounds like your rotor and bearing are just too small. struts struts struts

Well yah, the blades pull away on all my helis too. It's just on this one they pull away so far that they snap. Might add some screenies

 

Ok so I did the math on the control surface heli blades idea. So on my "traditional heli", at hover power, the main rotor spins at just over 1800deg/s. I'm just going to say that that's what it spins at, for simplicity.

This means that it takes 1/10th of a second for it to make 1/2 rotation.

The fastest moving control surfaces are the Big-S Elevons & 2, at 40degrees/sec.

40/10 = 4 degrees

Considering that the rotor blades on this particular heli have only a 5 degree angle of attack, this is the difference between having lift and having almost none at all! Perhaps this could have something to it?

Also, perhaps a better system would be to have a swashplate that only controls cyclic and have a KOS script do the collective? This way the blades could be one piece and thus centrifugal forces wouldn't make them fly off?

 

Edited August 9, 2016 by EpicSpaceTroll139
Maths

[Majorjim!]

1 hour ago, Jon144 said:

Well as you see the blades pull away on every helicopter I have ever made and especially so with the Chinook. It's just a matter of building the bearing and rotor strong enough. The blades pulling away from themselves is normal on any stock prop. You can always try adding more struts. But it sounds like your rotor and bearing are just too small. struts struts struts

Its my bearing design mostly but not my rotor. 

 And the blades coming away has nothing to do with the size of the bearing dude.. It just most likely requires a strut from the body to the blade. But as I said it's not my heli and I have not seen it but I do know the bearing is not too small or failing. ;-)

[Azimech]

Flies better now, more fuel, better fuel economy, far from finished and the bearing fails at 16+ m/s flight in every direction except up or down.

But the most important part: it's starting to look good.

[Gman_builder]

@Azimech What is the main rotor head speed on that heli?

[Azimech]

7 minutes ago, Gman_builder said:

@Azimech What is the main rotor head speed on that heli?

26 - 29 rad/s.

[Gman_builder]

I wonder if using KJR could actually create more compact engines that can run at higher RPM. Blade expansion is a serious limiting factor in RPM and thrust capabilities so being able to reduce it with a mod like KJR or hopefully some other way in stock might be beneficial. I've been thinking of concepts for engines based after the CFM International LEAP. I know it's not really to different than other turbofans but i was reading a lot about it and thought it would be a fun engine to base my stuff on.

[Jon144]

11 hours ago, Gman_builder said:

Ya we don't use KJR. It can actually cause performance limitations if combined with the right mods. As I have found.

Well then people who use whatever you make will be required to download KJR as well in order to use the craft. So at that rate why not just download a propeller mod or infernal robotics and attach a rotor to that. The glory about stock bearings, stock turboshafts, stock helicopters is anyone can download and appreciate them with a stock install of the game. A bearing made for KJR will not perform the same in the stock version and vice versa. 

[Gman_builder]

22 minutes ago, Jon144 said:

Well then people who use whatever you make will be required to download KJR as well in order to use the craft. So at that rate why not just download a propeller mod or infernal robotics and attach a rotor to that. The glory about stock bearings, stock turboshafts, stock helicopters is anyone can download and appreciate them with a stock install of the game. A bearing made for KJR will not perform the same in the stock version and vice versa. 

I didnt say it was practical. It was just a concept. Either way my initial testing was a failure anyway so forget all of that.

[Azimech]

 

WIP changelog:

• Surprise! I've switched to semi-wheelless bearing on the helicopter. I replaced the array of 26 small landing gears with 4 medium sized, placed small I beams radially around top & bottom of the shaft. I get better results with the wheels but even the medium landing gears break. After that It just loses some performance. Good for helicopters, bad for turboprops.
• Reduced blower count from 72 to 40 ... much better FPS.
• Reduced rotor blade count from 5 to 3 ... better performance in all areas, easier to control. Five blades looks nice but if it doesn't work, it doesn't work. Won't go lower than 3, I'm obsessed with threefold symmetry.
• I was inspired by all the incredibly crafty minimal bearings by various ppl kickstarted by @Majorjim! and had a look at the tailrotor by @EpicSpaceTroll139 and so made one for myself. Pure for looks and it rotates slowly but I don't care.
• Gave it some stubby wings and moved the main landing gear to the edges.
• improved the skin somewhat ... it's still rough but looking better.
• Good news, unlike fast turboprops, this helicopter doesn't need any tweaking of physics. It will work on any platform 100% stock.
• Aerobatics are possible and if left alone, SAS will keep it balanced.
• Autorotation works somewhat, was able to touch down without damage.

Can't decide what to do with the interiour ... part count is already high as it is. The enormous amount of mass large paneling brings ... not appealing at all.

Almost completed a looping with it!

Short GIF anim:

http://imgur.com/a/iJgij

[Majorjim!]

29 minutes ago, Azimech said:

I was inspired by all the incredibly crafty minimal bearings by various ppl kickstarted by @Majorjim!

Tee hee, does that mean your tail rotor uses a thermo hinge?

[Jon144]

5 hours ago, Azimech said:

 

• Surprise! I've switched to semi-wheelless bearing on the helicopter. I replaced the array of 26 small landing gears with 4 medium sized, placed small I beams radially around top & bottom of the shaft. I get better results with the wheels but even the medium landing gears break. After that It just loses some performance. Good for helicopters, bad for turboprops.
• Good news, unlike fast turboprops, this helicopter doesn't need any tweaking of physics. It will work on any platform 100% stock.

Maybe you're just not good at making wheel-less bearings? I have not put a single wheel in a bearing since the update broke them. Have never been kept from making a functional bearing now with the proper tweaking.

And on point two are you still forgetting people have to mod the game to get rid of the smoke or suffer from devastating FPS? Is there ever a way that you could only use one of two blowers?

What is the part count and fuel efficiency looking like for this one?

Edited August 10, 2016 by Jon144

[Azimech]

1 hour ago, Jon144 said:

Maybe you're just not good at making wheel-less bearings? I have not put a single wheel in a bearing since the update broke them. Have never been kept from making a functional bearing now with the proper tweaking.

It's the first wheelless I've put to use, all the dozens I've built in the last years were so disappointing
on the testbench (unloaded and horizontal) that I didn't realize they could be useful in vertical and with a hefty mass as a flywheel.
If you'd seen the angular speed jumping like that with a proper readout, you probably would've never used it ... they're tough but have incredibly high friction and can only exist in the science-friction world of KSP.

 

1 hour ago, Jon144 said:

And on point two are you still forgetting people have to mod the game to get rid of the smoke or suffer from devastating FPS? Is there ever a way that you could only use one of two blowers?

What is the part count and fuel efficiency looking like for this one?

It's anyone own responsibility to mod the smoke out ... but I've sent a clear message to the devs: the smoke & spool times of the jet engines are in the realm of science friction as well.

Two blowers? Give the basic jet engine (pardon ... wheesley) it's exhaust thrust back.

Part count with this one: 424.
Mass: 62.3 tons
Amount of fuel units: too lazy to count atm.
Max flight time: ehm ... 30 minutes?
 

5 hours ago, Majorjim! said:

Tee hee, does that mean your tail rotor uses a thermo hinge?

Yep ... but with nose cones.