Azimech

[Stock Helicopters & Turboprops] First flight around Kerbin! (page 49)

1703 posts in this topic

8 minutes ago, klond said:

 Its crazy how long it takes sometimes.  Build, test, crash, tweak, test, fail, scrap it, do-over, etc.  All the effort expended makes good results feel amazing.

@seiryu I do know that feeling of FINALY! :confused: haha

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I'm schoolgirl excited to show this tilt-rotor mechanism.  Use two rcs balls to pinch the airbrake.  Move limiter slider to hold angle.  The point where the airbrake is installed allows almost 90 degrees movement with high (infinite?) torque to hold position.

l0ExukZFOkLZgnyW4.gif

The best part?

Ready?

-If you put the tilting mechanism's pivot point on the blower's centerline like this you can leave the blowers connected to the main craft and never have to toggle to other craft !

l0Ex4edz8spFMUolG.gif

 

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58 minutes ago, klond said:

I'm schoolgirl excited to show this tilt-rotor mechanism.  Use two rcs balls to pinch the airbrake.  Move limiter slider to hold angle.  The point where the airbrake is installed allows almost 90 degrees movement with high (infinite?) torque to hold position.

l0ExukZFOkLZgnyW4.gif

The best part?

Ready?

-If you put the tilting mechanism's pivot point on the blower's centerline like this you can leave the blowers connected to the main craft and never have to toggle to other craft !

l0Ex4edz8spFMUolG.gif

 

Another impressive design, I started on one and it's not running smoothly at all, yours looks like nothing but smooth! On another note my son is on the HMX-1 team. A proud dad here for sure.

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After a solid eight minutes of extreme engineering, we have managed to create a bi-propeller light cargo helicopter with heavily modified PR-0P engines ripped from an earlier turboprop helicopter. It has only experienced one catastrophic failure so far!

c1MfRP0.png

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6 hours ago, klond said:

I'm schoolgirl excited to show this tilt-rotor mechanism.  Use two rcs balls to pinch the airbrake.  Move limiter slider to hold angle.  The point where the airbrake is installed allows almost 90 degrees movement with high (infinite?) torque to hold position.

The best part?

Ready?

-If you put the tilting mechanism's pivot point on the blower's centerline like this you can leave the blowers connected to the main craft and never have to toggle to other craft

I had been thinking just a few days ago about a similar no-switch-needed tilt-rotor design. Glad to see someone else thought of it and made it work.

But does it fly? In my experience horizontal flight and vertical flight typically require drastically different blade pitch. That's why I haven't really pursued it. (I might now though, if it works).

Edited by EpicSpaceTroll139

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43 minutes ago, EpicSpaceTroll139 said:

But does it fly? In my experience horizontal flight and vertical flight typically require drastically different blade pitch.

 That's why I couldn't bring myself to post the craft file.  It's fine vertically but it makes a terrible plane :(

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8 minutes ago, klond said:

 That's why I couldn't bring myself to post the craft file.  It's fine vertically but it makes a terrible plane :(

Hmmm... wasn't there some kind of K-OS constant speed propeller script on here a while back? Maybe it could be useful here?   ofc it wouldn't be fully stock then tho...

Perhaps action groups on the propellers for changing to cruise pitch could allow mode change with just a quick couple switches. At least you would still have throttle on the main craft.

Edited by EpicSpaceTroll139

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 Maybe if I can crank up the power I can set the blade pitch for high speed and use brute force to lift vertically.  I'll re-engineer and drop a gif if everything goes ok.  Might take some time.

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10 hours ago, Castille7 said:

my son is on the HMX-1 team

The osprey one?

1920px-HMX-1_MV-22B.JPG

 

 

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1 hour ago, klond said:

The osprey one?

1920px-HMX-1_MV-22B.JPG

 

 

Yes that one!

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Yesterday I was testing one of my seaplanes on Eve and Laythe. While doing that I've accidentally found out that if the plane is landed, you can safely engage the time warp, and the engines which where decoupled from the plane wouldn't break or pop out of the fairing after stopping the time warp. You can also get back to the space center and then get back to the plane or use the other vehicle to move in and out the physics range of the plane, and the engines will be fine after that.

In other words plane is reusable, without the need to re-dock the propellers to the plane.

After that I've tested my other airplanes which use faring bearing, and besides the Galeb seaplane this worked for Ik-5 and few other planes which use same or similar engines.

On the other hand this didn't work on the planes where faring closes on the nose cone adapter, although I might be able fix that, also it didn't work with the engines that use the structural fuselage.

 

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10 hours ago, EpicSpaceTroll139 said:

Hmmm... wasn't there some kind of K-OS constant speed propeller script on here a while back? Maybe it could be useful here?   ofc it wouldn't be fully stock then tho...

Perhaps action groups on the propellers for changing to cruise pitch could allow mode change with just a quick couple switches. At least you would still have throttle on the main craft.

You can only switch between deploy with action groups but a two-stage adjustable prop is better than none. The kOS script is buried somewhere in this topic (maybe 4 months back?) but it's only for 1 engine/prop.

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7 hours ago, _Rade said:

Yesterday I was testing one of my seaplanes on Eve and Laythe. While doing that I've accidentally found out that if the plane is landed, you can safely engage the time warp, and the engines which where decoupled from the plane wouldn't break or pop out of the fairing after stopping the time warp. You can also get back to the space center and then get back to the plane or use the other vehicle to move in and out the physics range of the plane, and the engines will be fine after that.

In other words plane is reusable, without the need to re-dock the propellers to the plane.

After that I've tested my other airplanes which use faring bearing, and besides the Galeb seaplane this worked for Ik-5 and few other planes which use same or similar engines.

On the other hand this didn't work on the planes where faring closes on the nose cone adapter, although I might be able fix that, also it didn't work with the engines that use the structural fuselage.

 

Yes, these engines can be stored. But always make sure they've stopped turning before leaving the scene or going outside physics range.

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Well, that's new to me, I always thought that they would break if you used time warp or leave the scene.

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27 minutes ago, _Rade said:

Well, that's new to me, I always thought that they would break if you used time warp or leave the scene.

During 0.90 this was true.

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Really stoked!

I made some modifications, took off and accelerated. Then suddenly the left engine developed a vibration. Before I knew it, it ripped itself off its mount. I immediately killed power to the other engine and proceeded on the forward motion jets. Eventually I restarted the right engine with a low power setting and was able to land safely! Boy, all the practice flying bombers in the IL2 series really pays off!

CR3EHWb.png

gTHMXEt.png

DRjhFfa.png

 

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11 hours ago, Azimech said:

(stuff)

That helicopter is looking pretty good so far, other than the part when an engine decided to leave the rest of the plane.

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News: It seems Kerbal Joint Reinforcement inhibits correct operation of turboshaft/turboprop engines. Please disable or the engine won't run fast enough for flight.

 

Example, the Asura II engine used in the Titans:

Engine angular speed at max power without KJR: 24 rad/s.

Engine angular speed at max power with KJR: 10 rad/s.

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Posted (edited)

I was cleaning up my SPH and VAB crafts menu to make it easier to find the replicas and other stuff I've been working on, and I came across this.

2017-03-19%2014-29-15.png

The name is a spoof of the "Rare Bear" from the Reno Air Races, even though this plane doesn't look like it with the sleek nose.

It can go a little over 110m/s (default aero), and the design looks like it has plenty of room for improvement. The engine compartment is only about half used, meaning either the number of blowers for the propeller can be doubled, or a second coaxial propeller can have its motor located there. Probably the latter, as the torque from this engine already is enough that the starboard wing had to be made 2 panels longer than the port one, and makes it hard to control at low speeds. I also have no idea if the number of blades on the prop is optimal or not.

An interesting thing I discovered is that if the engine's cargo bay is completely closed, the turbine elements will overheat, but if it is open even a tiny crack, they won't. I wish I could close it all the way as this would have the minimum drag, but ah well. Having it open by a tiny crack is still a lot better than having it open all the way.

 

I also took a break from working on the Saturn S-IVB to test out the flexible prop-rotor blade mount I mentioned earlier. It looks like it could work, but it's proving hard to make a torsion bearing good enough for use in an actual craft. Currently the blades need weights on their tips to keep from bending upwards into a cone, which makes me worried as to what gyroscopic effects will do with a tilting version, or even just during maneuvers.

Edited by EpicSpaceTroll139
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8 minutes ago, EpicSpaceTroll139 said:

An interesting thing I discovered is that if the engine's cargo bay is completely closed, the turbine elements will overheat, but if it is even a tiny crack, they won't. I wish I could close it all the way as this would have the minimum drag, but ah well. Having it open by a tiny crack is still a lot better than having it open all the way.

Aesthetically, you mean?  As far as the stock aero is concerned - if it's closed the contents are shielded, if it's open anywhere between 0.000001 and 100%, it's open and unshielded.

I'm sure you've tried this, but Alt-F12 -> Physics -> Aero -> "Display Aero Data in Action Menus" will reveal a 'shielded' / 'not shielded' note in the part's right click menu

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Posted (edited)

7 hours ago, fourfa said:

Aesthetically, you mean?  As far as the stock aero is concerned - if it's closed the contents are shielded, if it's open anywhere between 0.000001 and 100%, it's open and unshielded.

I'm sure you've tried this, but Alt-F12 -> Physics -> Aero -> "Display Aero Data in Action Menus" will reveal a 'shielded' / 'not shielded' note in the part's right click menu

I thought that too, but for some reason the plane goes faster the closer the doors are to being closed (I've tested it). I'll check the drag values. Maybe Squad made the cargo bay aero physics smarter with 1.2.2?

Edited by EpicSpaceTroll139
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14 hours ago, EpicSpaceTroll139 said:

I thought that too, but for some reason the plane goes faster the closer the doors are to being closed (I've tested it). I'll check the drag values. Maybe Squad made the cargo bay aero physics smarter with 1.2.2?

I think it's because that reduces the cargo bay drag, but not the stuff inside it.  A few radiators would probably be better.

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10 hours ago, EpicSpaceTroll139 said:

It can go a little over 110m/s (default aero),

That's fast.

Quote

Probably the latter, as the torque from this engine already is enough that the starboard wing had to be made 2 panels longer than the port one, and makes it hard to control at low speeds. I also have no idea if the number of blades on the prop is optimal or not.

Fascinating solution :-) I've never used an asymmetrical wing design when building these birds. Usually I just clip together extra control surfaces. Prop pitch angle has an influence on rolling tendency.

The number of blades is usually a matter of trial and error. My first turboprops had a lot of blades (6 - 12 blades) during 0.90. I think it's interesting to (re-)develop some science with the variable prop and the revised 1.2.x drag values.

Quote

An interesting thing I discovered is that if the engine's cargo bay is completely closed, the turbine elements will overheat, but if it is open even a tiny crack, they won't. I wish I could close it all the way as this would have the minimum drag, but ah well. Having it open by a tiny crack is still a lot better than having it open all the way.

I see you've extended the prop shaft through the fuel tank making it semi-virtual (a hack?). Interesting approach, I never wanted to do that but it creates new possibilities and for sure a lower drag. Look at my Azi-19, the first turboprop with a cooling system. This way you might be able to lower the drag some more. https://kerbalx.com/Azimech/77I--Azi19-Jolly-Jinn

 

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8 hours ago, Azimech said:

That's fast.

Fascinating solution :-) I've never used an asymmetrical wing design when building these birds. Usually I just clip together extra control surfaces. Prop pitch angle has an influence on rolling tendency.

<snip>

Look at my Azi-19, the first turboprop with a cooling system. This way you might be able to lower the drag some more. https://kerbalx.com/Azimech/77I--Azi19-Jolly-Jinn

Yah, the asymmetrical wing design can help a fair bit, but when carried to the extreme like on this design, it can cause problems. For example, if the engine fails or is idled in flight, the asymmetric lift now has nothing to counter, so the plane will go into a spiral.

I've set up the plane with contrarotating props now, but it doesn't go any faster because the only hub design I've got so far that keeps the props from breaking is also incredibly draggy (as in two exposed-2.5m-flat-faces draggy). I'll see if I can figure out some way to use radiators to cool it like your Jolly Jinn.

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well,I made a small 20 parts electrolic prop.

It's pretty small. Right?

kjEgZIl.png

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