First Turboprop Flight in 1.1.1230!

[Azimech]

Turboshaft engines are a thing again! This 1.0.4 airplane needed 25 blowers at max power to get into the air. The 1.1 version has 20 and look at the throttle setting ... and it's without afterburner!

 

 

Squad, thank you very much for all your hard work! You've made a whole lot of people very happy! And the turboshaft guys as well!

_{Now we could use just a little more tweaking at the ability of the landing gears to withstand the forces ... the stock bearing failed after 2:30 :-P}

Edited April 19, 2016 by Azimech

[selfish_meme]

Methinks you could halve the size of the craft now

[Jon144]

How in the world did you build the bearing? I can't make a single one where the wheels don't become "overstressesed" or just clip through the rest of the craft. I don't think I will ever be able to build anything to share on the forum again.

Anyways I hope you can at least keep the rotation dream alive and well. It's not like any of stuff using them was that great anyways. It's really cool how you exhaust force is working now. That might be something to look into.

Edited April 20, 2016 by Jon144

[Azimech]

2 hours ago, Jon144 said:

How in the world did you build the bearing? I can't make a single one where the wheels don't become "overstressesed" or just clip through the rest of the craft. I don't think I will ever be able to build anything to share on the forum again.

Anyways I hope you can at least keep the rotation dream alive and well. It's not like any of stuff using them was that great anyways. It's really cool how you exhaust force is working now. That might be something to look into.

Don't give up! Your creativity and attention to detail is inspiring! The only way I currently know is to use larger wheels and if that's not possible, add more.

[Pds314]

23 hours ago, Azimech said:

Don't give up! Your creativity and attention to detail is inspiring! The only way I currently know is to use larger wheels and if that's not possible, add more.

Might it be doable to not use wheels and simply deal with the extra friction on a very small part? I know people have designed antenna-based bearings, although those are mainly used for things like doors.

[Adarsh]

Is 1.1.1230 the pre release?

[Azimech]

1 hour ago, Adarsh said:

Is 1.1.1230 the pre release?

Nope, it's the official 1.1 release, for everyone.

Prototype turboprop airplane in 1.1, this one has a reliable engine (after many hours of searching for a solution) and for the first time ever, features stock adjustable propeller pitch! Credits for the idea go to @sgt_flyer.

The adjustable prop pitch is due to some changed code with the 1.1 update. Again, thanks Squad!

A few stats.
Part count:
Aircraft without turbine shaft: 263,
Turbine shaft + propeller: 56
Mass: 75 tons,
Blowers: 60x Juno.
Max speed: ~60 m/s.
Ceiling: still testing.
Max engine rpm: ~325.
 

Edited April 21, 2016 by Azimech

[Padishar]

14 minutes ago, Azimech said:

A few stats:

75 tons,
60 Juno blowers.

Nice work...  Total part (and vessel) count?

[Azimech]

34 minutes ago, Padishar said:

Nice work...  Total part (and vessel) count?

Updated previous post.

Edited April 21, 2016 by Azimech

[Mad Rocket Scientist]

Amazingly quick response to 1.1!

On 4/19/2016 at 4:45 PM, Azimech said:

the stock bearing failed after 2:30 :-P

Yeah, the wheels are way to weak in some situations.  Especially since they can't be repaired.

[Pds314]

We need a competition for 1.1 Turbos...

[Jon144]

3 hours ago, Pds314 said:

We need a competition for 1.1 Turbos...

Won't happen until it's possible to make bearings like before

[Pds314]

2 hours ago, Jon144 said:

Won't happen until it's possible to make bearings like before

I made an engine that seems to work. It uses 6 LY-05 and 3 Juno blowers and weighs like 2.6 tonnes. I managed to get it to hover pretty well in 0.5 Gee with about a tonne of extra stuff for control, so that's at least ~20 kN static thrust. It doesn't break either. Well, not unless you crash.

If we made a competition, people could submit their rotors and communally improve them. Also, the thin-rod design actually looks promising. I used the avionics nosecone and it holds in place quite well.

EDIT: have a working 3-blower prop without wheels, problem is, it as truly anemic thrust

EDIT 2: revised it to use MOAR BLOWERS (6 of them) and have marginally larger blower radius. Probably need to do a total redesign to give it a TWR over 0.5. 3-blower version weighed a puny 1.7 tonnes with prop.

EDIT 3: also using FAR. Don't know how this effects these, but my engines will almost certainly behave very differently on other machines.

EDIT 4: someone really needs to make a thrust-tester device. I suspect the old one is no longer functional.

 

EDIT 5 probably going to go for larger diameter engine. The torque on these little ones is just too low to be practical. 0.5-meter blower paddle radius means each blower generates very little torque.

EDIT 6: Hmm.. I wonder how hard it would be to make a chinook- like helicopter with these sort of engines? Maybe get a couple 12x juno blower engines with some very relaxed blade pitch on the props, give them a paddle radius of like nearly 2.5m, that's like... 20 times the torque of my little LY-05 based engine. Should be enough to lift something fairly decent-sized. Add grabbers and it's time to play cupcake.

Edited April 22, 2016 by Pds314

[Pds314]

You know you're doing something really darn right when your prop pulls off of the engine shaft and flies 200 meters into the air, and the shaft stay in the engine.

Edited April 22, 2016 by Pds314

[Azimech]

5 hours ago, Pds314 said:

EDIT 4: someone really needs to make a thrust-tester device. I suspect the old one is no longer functional.

 

It's working with just a few bangs with a large hammer. I'll upload the updated version soon.

[Pds314]

4 minutes ago, Azimech said:

It's working with just a few bangs with a large hammer. I'll upload the updated version soon.

Do you know if the aero arrows mean anything useful or how to accurately read them as to kilonewtons of lift?

[Azimech]

Just now, Pds314 said:

Do you know if the aero arrows mean anything useful or how to accurately read them as to kilonewtons of lift?

 

Yes, because I designed it :-P
First you use test the engine and read the position of the needle on the scale. Then shut down it down and power up the turbofan on the rear; adjust it's thrust with the thrust limiter until the needle rest at the same spot.

There might be an easier or quicker method but I like it :-)

 

[Pds314]

2 minutes ago, Azimech said:

 

Yes, because I designed it :-P
First you use test the engine and read the position of the needle on the scale. Then shut down it down and power up the turbofan on the rear; adjust it's thrust with the thrust limiter until the needle rest at the same spot.

There might be an easier or quicker method but I like it :-)

 

Oh, no, I meant F12, lol. I know how to use your device.

[Azimech]

Just now, Pds314 said:

Oh, no, I meant F12, lol. I know how to use your device.

Ah those arrows! Hmmm ... no. And I'm going to write a bug report, because control surface aerodynamic data is not being displayed.

Let's continue in the big old topic

 

[Majorjim!]

So does this work 100% of the time Azi or does it reliably break due to the wheel issues?

[Azimech]

7 minutes ago, Majorjim said:

So does this work 100% of the time Azi or does it reliably break due to the wheel issues?

It's my best bearing ever despite the wheel problems. I'll upload it soon, first I have to decide if the pilot gets square or rectangular feet.

[Majorjim!]

Just now, Azimech said:

It's my best bearing ever despite the wheel problems. I'll upload it soon, first I have to decide if the pilot gets square or rectangular feet.

So what is causing it to break? Are the wheels breaking or flexing causing instability?

[Majorjim!]

On 04/20/2016 at 4:10 AM, Jon144 said:

How in the world did you build the bearing?

Azi says his fails too, its not just you dude. Using more seems to reduce the time to failure but it will reliably fail.

[Azimech]

2 hours ago, Majorjim said:

So what is causing it to break? Are the wheels breaking or flexing causing instability?

In my case it's because of harmonic vibration: tiny difference in blade thrust together with a little bit too much bearing clearance (to reduce friction) creates a self-inducing wobble, creating the situation of more blades having unequal or loss of thrust, causing the turbine shaft to bounce back and forth. Correct blade angle has a positive effect.

 

Something else: we're back in business!

 

To enjoy helicopters and airplanes like they were in 0.90, you only need to do one thing:

Open the debug menu, click the drag tab, switch off "Apply non-physical part drag at parent CoM"

My plane was struggling to go past 50m/s in level flight. It immediately accelerated to 100m/s. Currently it's climbing at 11km altitude with a speed of 116m/s, blower thrust 5.9kN (it's got 72 Juno's, mind you).

So ... this opens up new possibilities! My next project is trying to create a "tiny" & "light" turboprop with a modest amount of parts and only two blowers.

Variable pitch propellers and engine rpm readout suddenly have become very important!

 

Edit: I was too quick ... it produces NRE's. I'll ask Squad what it means.

Edit 2: a better solution is to just slide the "Global Drag Multiplier" all the way to the left.

Edited April 22, 2016 by Azimech

[Wjolcz]

I built a triebflugel thing. Does it count?