Stock BG KerboProp Aircraft Speed Challenge!

[g00bd0g]

This challenge is simple. Go as fast as possible in level flight at any altitude using the new BG motors and prop parts. The spirit of the challenge is to create "realistic" (in the Kerbal universe) prop driven aircraft. This means stock parts only, stock props or rotors for propulsion only, no reaction wheels and no torque enabled, no cheaty clipping or assembly techniques. For example, you can put parts inside of structural tube, but not clipped into a fuel tank. You cannot clip 100 motors into each other, etc...

• Must takeoff from the runway, perform the speed run, and land on the runway, with same parts you started with.
• No parachutes for vertical landing, though drogue chutes for decelerating are fine...
• Must maintain altitude +/- 10 meters over 10 seconds for the speed run. Lowest speed value displayed will be your record.
• No parts or physics mods. Graphics and info mods allowed.
• I will maintain Electric (including Fuel Cell) and LF categories.
• Video or sufficient pics for evidence required, craft file may be requested for validation.
• Must provide craft name, claimed speed, and timestamp start and stop for speed run.

I'll kick it off with my Kornier Ko 335!

https://kerbalx.com/g00bd0g/Kornier-Ko-335

Leader Boards

Electric

Pds314 - unnamed? - 301.5 *(did not land on runway)

g00bd0g - Kornier Ko 335 - 290.5

LF

mystified - Barbwire Canoe - 298.6

mystified - Broad Arrow - 291.2

Frozen_Heart - Pr-1C Biplane - 150

 

 

 

Edited July 21, 2019 by g00bd0g

[XLjedi]

Should we post the current RL world record holder for propeller driven aircraft? 

https://en.wikipedia.org/wiki/Fastest_propeller-driven_aircraft

...just as a point of reference.

 

[Frozen_Heart]

Got about 150m/s with the Pr-1C Biplane. Was too uncontrollable to keep it steady for long enough to get faster. Will put up the vid tomorrow as taking a few hours to upload.

[g00bd0g]

10 hours ago, XLjedi said:

Should we post the current RL world record holder for propeller driven aircraft? 

https://en.wikipedia.org/wiki/Fastest_propeller-driven_aircraft

...just as a point of reference.

 

Sure! some pretty Kerbal planes there

[Frozen_Heart]

Ok here is my entry: The Pr-1C Biplane. 

 

Yes it's kind of a joke entry, but that's still first on the LF leaderboard

 

 

Edited July 18, 2019 by Frozen_Heart

[mystifeid]

Something completely different - the flying pig Broad Arrow. Uses 16 turboshaft engines. Top speed - 291.2m/s.

Craft file.

 

[Pds314]

Is there a category for planes with no electric OR LF?

Edited July 19, 2019 by Pds314

[Frozen_Heart]

1 hour ago, Pds314 said:

Is there a category for planes with no electric OR LF?

*Squints*

[g00bd0g]

4 hours ago, Pds314 said:

Is there a category for planes with no electric OR LF?

If  it's propelled by the new BG props let's see it.

10 hours ago, mystifeid said:

Something completely different - the flying pig Broad Arrow. Uses 16 turboshaft engines. Top speed - 291.2m/s.

Very nice! I think the top prop speed might just be in the low 290's. Until someone proves otherwise...

[Frozen_Heart]

Manged 298m/s but not managed to land the thing or keep it steady enough for the entire 10 seconds yet. Needs some refining still. 

[Pds314]

I don't have sufficient evidence nor am I at a computer with KSP right now but I've managed in the low to mid 290s.

2 hours ago, Frozen_Heart said:

Manged 298m/s but not managed to land the thing or keep it steady enough for the entire 10 seconds yet. Needs some refining still. 

298 is very impressive indeed.

[Pds314]

It isn't up to competitive speeds yet, but it is an unpowered 260 m/s plane. I think the next step is increasing the blade count. Since I'm getting many problems I normally encounter at 280 at 260. Probably because of additional drag from the turbine.

Edited July 20, 2019 by Pds314

[g00bd0g]

1 hour ago, Pds314 said:

It isn't up to competitive speeds yet, but it is an unpowered 260 m/s plane. I think the next step is increasing the blade count. Since I'm getting many problems I normally encounter at 280 at 260. Probably because of additional drag from the turbine.

Just remember "stock parts only, stock props or rotors for propulsion only". This mean no rotary wings or other parts for propulsion.

[Pds314]

12 minutes ago, g00bd0g said:

Just remember "stock parts only, stock props or rotors for propulsion only". This mean no rotary wings or other parts for propulsion.

So the lift vectors from the rotary wings are all facing horizontal or actually slightly backwards. They are in autorotation. They do not generate any forward thrust themselves. They generate mountains of torque at high speed but negative net thrust.

 

What generates all forward thrust is the prop blades.

 

IDK if there are rules here on torque generation methods. Besides no reaction wheels ofc.

Edited July 20, 2019 by Pds314

[Pds314]

It's interesting. You'd think more power would always be a good thing, but this seems to prove that is not the case.

I think the issue is that prop blades are reaching mach very early.

[mystifeid]

59 minutes ago, Pds314 said:

It's interesting. You'd think more power would always be a good thing, but this seems to prove that is not the case.

With a lot of the aircraft I've tried, when torque is at 100% and current rpm at 460, the best speed I can get by reducing blade authority is usually around 230-240. Often, reducing the blade authority then automatically reduces the current rpm to 200-300 allowing further reduction in blade authority (in the video above I'm doing 291m/s with 213rpm). Sometimes though, the current rpm doesn't drop by itself and reducing the rpm limit becomes necessary to reduce blade authority for optimum speed.

After having a look at the Kornier, @g00bd0g sets engines and props up differently to me so you might have to translate what is above according to your setup.

Also, the 16 engine beast achieved best speeds flying beween 1500-1800m and I thought that might be the case for all aircraft but now I'm swinging the other way - you just have to find the right altitude for your particular design.

And I've found that fine control (caps-lock) does not seem to affect the throttle keys but it does affect the custom axis groups. So I've stopped assigning anything to the main throttle axis group. With caps-lock on I can change, for example, the blade authority by 0.5% with a tap of a custom axis group key.

Edited July 21, 2019 by mystifeid

[Pds314]

301.4 m/s with motors. For some reason the landing broke the runway.

 

Edited July 21, 2019 by Pds314

[mystifeid]

19 minutes ago, Pds314 said:

For some reason the landing broke the runway

Looks like one of your prop blades hit the runway when you first touched down - I've seen that puff of smoke a lot of times before.

Anyway, more blades then. I wonder what another 128 blades will do for me. No time now though.

[g00bd0g]

1 hour ago, Pds314 said:

301.4 m/s with motors. For some reason the landing broke the runway.

That plane is sweet. However, no physics mods allowed (added to rules list), and you definitely did not finish with the same part count you started with 

[qzgy]

25 minutes ago, g00bd0g said:

That plane is sweet. However, no physics mods allowed (added to rules list), and you definitely did not finish with the same part count you started with 

Sorry, but looking at it the only mod was physics range extender which doesn't actually affect the aerodynamics portion of the craft. So your "no physics mods" statement, implying he was using one, is not relevant.

Yes, I'd agree the landing was botched but it looks like it could be done (just quite difficult), but on the other hand its not intentionally shedding parts.

Edited July 21, 2019 by qzgy

[Pds314]

1 hour ago, g00bd0g said:

That plane is sweet. However, no physics mods allowed (added to rules list), and you definitely did not finish with the same part count you started with 

"No physics mods allowed"
Such as?

PRE does not change physics. It extends stock physics loading range. Which isn't even relevant here. Obviously the plane reached 301.4 m/s in stock physics and is capable of landing. Even if I messed that particular landing up.

Edited July 21, 2019 by Pds314

[g00bd0g]

A successful intact landing on the runway is a requirement and part of the challenge. This ensures aircraft are actually stable and handle well and have low enough stall speeds to land without RUD. Also adding a no parachutes for vertical descent rule, OK for horizontal decel.

Also, while I beleive PRE doesn't "intend" to change physics, how do we know? Have you or anyone ever validated it? Given that it DOES directly interact with physics code. I would rather disallow it unless it is proven to have no effect. If you can't be bothered to uninstall it for the challenge, I will just add a note to your entry, assuming you provide a valid entry with a landing and everything

Edited July 21, 2019 by g00bd0g

[Pds314]

39 minutes ago, g00bd0g said:

A successful intact landing on the runway is a requirement and part of the challenge. This ensures aircraft are actually stable and handle well and have low enough stall speeds to land without RUD. Also adding a no parachutes for vertical descent rule, OK for horizontal decel.

Also, while I beleive PRE doesn't "intend" to change physics, how do we know? Have you or anyone ever validated it? Given that it DOES directly interact with physics code. I would rather disallow it unless it is proven to have no effect.

Hyperedit can teleport the craft to Jool at millions of times the speed of light. Or teleport Jool to the craft for that matter, which is a way bigger physics alteration. But whatever. I can just press the disable mod button.

Question: would a landing with a non-disabling prop strike be disqualified? I.E. a minor enough prop strike to not prevent the craft from taking off again?

Edited July 21, 2019 by Pds314

[g00bd0g]

1 minute ago, Pds314 said:

Hyperedit can teleport the craft to Jool at millions of times the speed of light. Or teleport Jool to the craft for that matter, which is a way bigger physics alteration. But whatever. I can just press the disable mod button.

Question: would a landing with a non-disabling prop strike be disqualified?

If it destroys the part it is disqualifying.

[Pds314]

Alright. Another run at 301.7. No damage. No PRE. No runway-destroying.
Warning: music

 

Edited July 21, 2019 by Pds314