Azimech

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

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A swashplate made out of stock parts... even if it doesn't work, that's freaking cool!

It's hard to tell from the clip, which is obviously a cyclic test. Will it work for collective as well, or is there not enough play?

Edited by WhiteKnuckle

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Surprise! The very first Turboprop airplane! Fugly but it's all about those engines. And yes, something breaks in the left engine. It flew on for another 20 minutes :-)

fqGegGD.gif

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I like it, particularly the spindly undercarriage to get the prop clearance!

What if you increased ground clearance using a "gull wing" with the undercarriage at the wing low point? Like a Stuka bomber...

I want to try it...

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Download for my turboprop airplane is up! See the OP!

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Her top speed is a joke :-)

At sea level it's around 24m/s in level flight, I haven't tested it yet at higher altitudes. It doesn't have pitch control so it's very limited, otherwise the engines will overspeed and break apart.

But ... it's as close as we can get to a real turboprop in stock KSP. Unless a proper reduction gear will be invented by someone.

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Surprise! The very first Turboprop airplane! Fugly but it's all about those engines. And yes, something breaks in the left engine. It flew on for another 20 minutes :-)

http://i.imgur.com/fqGegGD.gif

Explain it like I'm 5

How does this work?

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Hay Azimech. Now that I've got some testing under my belt, I can say for sure that I know what happened to the left engine on your turboprop aircraft.(in the video) It blew out one of the turbine blades. I've had one of my earlier(yesterday) turboshaft engines do the same thing. They keep working as long as they still have an intact axle and half their blades. :) Safety margins ftw.

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Explain it like I'm 5

How does this work?

That's a long story! The best thing you could do is download a helicopter or the plane and test it.

- - - Updated - - -

Hay Azimech. Now that I've got some testing under my belt, I can say for sure that I know what happened to the left engine on your turboprop aircraft.(in the video) It blew out one of the turbine blades. I've had one of my earlier(yesterday) turboshaft engines do the same thing. They keep working as long as they still have an intact axle and half their blades. :) Safety margins ftw.

Yep, correct analysis :-) The turbine blades I used are of a smaller, less strong type than the 1x1 steel plates I usually use.

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New Turboprop airplane! Immensely more powerful than the previous! Check the OP!

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Another two variants added to the OP!

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Oh I like the Yelling Gazelle. A nice evolution of the Turbo-prop. I was thinking about adding more jets on the same row and will probably go that way. I did make the mistake of opening the cargo doors during flight which hit the props and ripped them off! :blush:

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Yeah, I thought it was funny, the props shortened a bit but the plane flew on! And indeed, making the powerplant longer is a better option for a turboprop, and probably for a helicopter engine as well. I'm going to use these uprated engines for my next twin helicopter, for sure. By the way, thanks Redshift, I did take a look at your bearing assembly. I dropped the conical idea somewhere in 2013, thought it wasn't up to the job. Now I see it indeed has more life! The adapters do explode at a high rpm, somewhere around 22 rad/s, and that limits the altitude of the Yelling Gazelle to around 3300m. There are worse things in life :-)

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My current experiment.

Completely stock. I'm still having problems with the control rod hinges, they're not flexible enough. Swash plate control is a problem too: the landing gears can only be toggled.

http://i.imgur.com/FXJJZZq.gif

I was reading through this going "wow" and then I saw this...brb cleaning up the remains of my jaw off the floor...

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I've developed a new kind of turboshaft engine. It ran at first try. Incredibly reliable, just need to improve performance and reduce vibrations.

Edited by Azimech

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Using Azimech's turboshaft engine from the 77I-7A2O "Screaming Turtle", I've built a much less ugly plane. Introducing, the WWII German dive bomber, the Stuka. It's only 175 parts.

I prioritized making it look as realistic as possible, but still able to fly. Because of this, the flight characteristics are rather poor--it has very little power. If you want more power, you can add a fin to each engine blade, or use wider blades, and it will fly MUCH better. Also, there are a large number of control surfaces (to replicate the look of the original stuka's dive brakes, etc), so there may be *some* infiniglide effects going on, but the prop provides the majority of the thrust. The purists may cry a tear or three. :)

Other things of note:

1) After flying Stuka, when you revert to launch, spaceplane hanger, or go to the space center, the game can crash. This is a bug in Kerbal, and I've reported it to the devs. This appears due to the engine--using Tsevion's engine I never had any crashes. However, it was too heavy to take off.

2) I strengthened Azimech's engine by adding a couple wheels, specifically on the top. This is because the load on the engine is not uniform, as the engine is horizontal. Other than that, it's his stock engine.

3) At full throttle, due to the small blades, there is a small chance that you can overspeed the RCS tanks in Azimech's engine, causing them to explode. If this happens, the prop will jam and stop operating. I recommend using 90% throttle, unless you want to live on the edge. Consider 100% war emergency--the engine may self-destruct. :)

4) Because of minimal thrust, I needed to reduce weight and removed most fuel. This puts the CG far forward, so I added reaction wheels to allow you to lower the tail. Without these (in the cargohold), you will not be able to lift off the ground. If you make a much larger prop, you can fill all of the fuel tanks, and you can remove the RCS wheels.

I plan to try to design my own engine, particularly to reduce weight and fix the overspeed explosions. I have a few ideas on how I might achieve that. However, if anyone wants to propose a lightweight engine, I'd be happy to use it in the Stuka.

screenshot19.png

screenshot21.png

screenshot27.png

Craft file:

http://lothsahn.com:3172/kerbal/Stuka-Lothsahn.craft

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This is a new turbine without the high speed problems of the bearings using tanks or other structural parts. With these, the landing gears are mounted on the shaft and rotate, running inside a shell of steel plates. Reliability goes up dramatically! They can even withstand some battle damage (untested). Overspeeding means the construction just jams, until power is dropped. Unfortunately, the increased drag means you lose quite some power, the construction is heavier and you obviously need more parts. But, if done correctly, you could build a tank with this. This one ran reliably on first try, but had only 50% of the power of my best engine. Actually that's not even bad.

LuouCeH.png

zwdWkig.png

Here is a lighter, parts reduced design during testing:

On the left the T8S8B4, 8 blade, 8 blower turboprop. On the right the NT8S8B4, same configuration, different bearing concept. The left one is the proven technology, pretty powerful but will fail dramatically when rpm goes in the red line, something that happens during climbing at 3400m at full power. Max rpm: around 210.

The right one doesn't have that flaw and can theoretically reach rpm's as high as 440 (as far as I know, the current KSP maximum), a lot more reliable and can even withstand some battle damage. But ... it has a lot of internal drag, thus producing only 85% of the power the other one has - which is unacceptable. Oh well ... teething problems.

90sTVKo.png

smGAXz5.png

uCxnvkz.gif

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77 Industries presents: The Azimech HN12!

Soon available for download! The first production model with a revolutionary new bearing system!

Use this giant to drive your huge propellers and helicopter rotors!

Will be available both as clockwise and anti-clockwise runners!

Javascript is disabled. View full album

Also coming soon: the HN8 and HN4.

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Yeah, I thought it was funny, the props shortened a bit but the plane flew on! And indeed, making the powerplant longer is a better option for a turboprop, and probably for a helicopter engine as well. I'm going to use these uprated engines for my next twin helicopter, for sure. By the way, thanks Redshift, I did take a look at your bearing assembly. I dropped the conical idea somewhere in 2013, thought it wasn't up to the job. Now I see it indeed has more life! The adapters do explode at a high rpm, somewhere around 22 rad/s, and that limits the altitude of the Yelling Gazelle to around 3300m. There are worse things in life :-)

No worries. I wasn't sure about the conical adapters either but they turned out all right with careful tweaking of the wheels. Glad I could help with the advancement of the engine technology!

Your new engine sounds exciting! I am certainly looking forward to trying it out. One thing I discovered was the "Better Time Warp" mod that lets you run the game in slow motion, (I think down to x0.05), which I am hoping will allow me to see where my latest design of engine is going wrong.

- - - Updated - - -

Also it looks like you do what I do. But 2 different engines / prop setups on one plane and whichever way the plane torques tells you which is more powerful. :)

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This is a new turbine without the high speed problems of the bearings using tanks or other structural parts. With these, the landing gears are mounted on the shaft and rotate, running inside a shell of steel plates. Reliability goes up dramatically! They can even withstand some battle damage (untested). Overspeeding means the construction just jams, until power is dropped. Unfortunately, the increased drag means you lose quite some power, the construction is heavier and you obviously need more parts. But, if done correctly, you could build a tank with this. This one ran reliably on first try, but had only 50% of the power of my best engine. Actually that's not even bad.

That's pretty creative, reversing the travel parts. :) I did not think of that.

However, the Juno 211D accomplishes the reliability without the power loss. It's roughly twice as powerful as your Screaming Turtle engine, without any added jets! I'm not sure how it compares to your strongest engine--please test and let me know.

In the event of overspeed, the engine will start randomly tugging on the airframe, which lets you know to throttle down. If you continue to overspeed, the engine will stop spinning until power is reduced, with no part breakage. With at least a 3 bladed prop attached, I've been unable to break the engine at any speed, altitude, or throttle setting unless I use physics warp. With 8 blades (as shown in the Stuka V4), it will not overspeed at any altitude that the Stuka is flyable at. With 3 blades, overspeed starts to occur around 800m at 100% throttle.

Design Specs:

This engine is designed to be high RPM's and high power, while keeping a compact profile (length and width). Some power is sacrificed to keep the profile smaller.

Engine weight: 8.7T

This engine is capable of pushing the Stuka to a maximum speed of 50.4 m/s @ 5700m altitude. The limiting factor actually becomes the loss of tail authority, as there is not a second prop to counter-balance the forces.

Design Details (for future modders):

Rotating parts in kerbal tend to expand as they rotate faster. You can see this in the propellers as they spin. This happens to the turbine blades too. By designing the engine to have high strength parts (1x1 panels & ibeams) be the collision points, you can cause the engine to jam without part loss. The bearing in the engine are modeled after the yelling gazelle, but using higher strength angled parts. These bearings mean that unless the shaft completely leaves the wheels, it will automatically reset itself when the engine is powered down.

The maximum RPM of this engine is directly dependent on the gap between the turbine blades and the i-beams. To keep the profile smaller, I had to rotate the turbine blades. This means they are not perpendicular with the jets, which (I think) is causing a small power loss. With a larger case, I believe the engine could provide even more power if it had perpendicular blades.

screenshot49.png

Craft File:

Juno 211D

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One thing I noticed with the turbine blades, at least on my design, was that if they spun too quickly centrifugal force pulls them away from the shaft and they end up hitting the engine frame causing a jam. I will have a look at your design.

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Lothsahn, I just had a look at your engine. Brilliant design! I didn't think of using NCS adapters in the bearings. They seem a lot tougher and have less friction than the FLA10 adaptors. 2 things I noticed though. 1) you are using 8 octagonal struts to hold the jets to the frame. You only need one. You attach the jet engine to it and then use the new offset ability to move the engine up and down and left and right to get it in the right orientation. It would save you at least 28 parts. 2) the turbine blades do pull away from the shaft. Adding some struts from the blades to the shaft lessens this and prevents jams by stopping the blades hitting the frame.

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Lothsahn, I just had a look at your engine. Brilliant design! I didn't think of using NCS adapters in the bearings. They seem a lot tougher and have less friction than the FLA10 adaptors. 2 things I noticed though. 1) you are using 8 octagonal struts to hold the jets to the frame. You only need one. You attach the jet engine to it and then use the new offset ability to move the engine up and down and left and right to get it in the right orientation. It would save you at least 28 parts. 2) the turbine blades do pull away from the shaft. Adding some struts from the blades to the shaft lessens this and prevents jams by stopping the blades hitting the frame.

1) Interesting. I'll look at this. Be careful though--the engine MUST be above the frame, or you'll have RUD when the turbine blades crash into the engine. The whole point of the engine is that the lowest point is the i-beam, NOT the jets. Also, it would save parts, but those parts are physicsless, so I don't think they'll affect performance that much... I guess if you're solely looking at parts count it'll make it look better.

2) I'll try adding struts. This might increase the maximum RPM easily.

Thanks for the input!

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