Pds314

[stock] Prop plane race: Island round-trip.

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Posted (edited)

The goal of this challenge is to reach the Island Runway in a stock propeller aircraft, land, turn around (you MUST turn around, exiting the runway facing 180 degrees from how you landed on it, though you may do so at any speed and do not need to stop on the runway), and get back to the KSC runway, where you must land and stop.

Complete the course in as little time as possible.

Okay new rule on fastest times: I'm not gonna put multiple runs of related development by the same person on the list. So clearly-unrelated planes can get one person multiple entries on the list but not just derivatives or multiple runs of the same aircraft with minor tweaks. I'll just mark the fastest run.

Fastest times:
1. Chargan in the The Polar Bear Express: 7:23
2. Pds314 in the Turboelectric Racer III: Pfailure Edition: 8:02
3. Pds314 in the Oof 1: 10:03

Edited by Pds314

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Posted (edited)

My attempt: 10:03 in the Oof 1

Spoiler

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Edited by Pds314

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Looks nice, i'll have to refine my designs since they vibrate so much the wings fall off sometimes from the vibrations

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9 hours ago, chargan said:

Here's a 9:09 run with a chunky, misshapen plane.

https://imgur.com/a/CIhNDOb

Whoa that thing is like a flying Polar Bear lol.

New record!

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Posted (edited)

Not gonna count the run because it's not on the runway, but I managed to crash-land within 8:26!

The plane in question is quite fast and quite hard to slow down. It has a small wing area to improve top speed.
FRgWl3c.png

Top sealevel speed is around 159-160 m/s, which I would say is pretty impressive for just 10 small reaction wheels.
M5VKJXc.png

Edited by Pds314

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A very bouncy landing but I managed to one-up chargan's plane. My camera is glitching out because of positional errors, i.e. the Kraken, due to BDArmory.

ptwTTaw.png

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So I dusted off my old twin-engine prop racer and took it for a test flight. It's fast, but I forgot how hard it is to control one stock prop, let alone two. I keep biffing the landing and breaking off propeller blades.

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Posted (edited)

8:02 in the Turboelectric Racer III: Pfailure edition. Also no damage, which is genuinely very surprising considering the non-propstrike takeoff and landing speeds are like >65 m/s.

This plane is painful to land and take off with in a way that's fast and doesn't destroy an engine. (I.E. you can't use aggressive windmill-braking).

3QrVJYe.png

 

Spoiler

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Edited by Pds314

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8 hours ago, Pds314 said:

Whoa that thing is like a flying Polar Bear lol.

New record!

I like it. Naming this The Polar Bear Express. Added 50% more powah and fiddled with the prop angle in-flight. Managed 7:23

https://imgur.com/a/HoVvRbX

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19 minutes ago, chargan said:

I like it. Naming this The Polar Bear Express. Added 50% more powah and fiddled with the prop angle in-flight. Managed 7:23

https://imgur.com/a/HoVvRbX

I'm impressed you managed 7:23 without actually going over 200 m/s. (Unless you did lol)

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29 minutes ago, Pds314 said:

I'm impressed you managed 7:23 without actually going over 200 m/s. (Unless you did lol)

No, maxed out around 190m/s. Guess it just gets up to speed/slows down much faster.

I'll try and add moar boosters reaction wheels to see if I can push it further.

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2 minutes ago, chargan said:

No, maxed out around 190m/s. Guess it just gets up to speed/slows down much faster.

I'll try and add moar boosters reaction wheels to see if I can push it further.

I think you either are better at landing or less sleek but accelerating than my craft. My Turboelectric Racer II can do 190 and it only has 20 small SAS wheels.

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Posted (edited)

Not exactly related (other than that all craft shown, including vaporized carrier, are/were prop-powered) but note-to-self, do not, under any circumstances, using Vessel mover on a craft which is parked on a carrier.

kAzrr1W.png

Edited by Pds314

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Posted (edited)
24 minutes ago, KosmoNot79 said:

bradley whistance made a video on how to build extremely fast prop planes if anyone needs some tips:

Breaking the stock propeller speed record in KSP (Over 1,000 m/s ...

 

Nice! Although keep in mind he started with a plane / giant egg with a tail and a prop that was supersonic. So if your plane currently does 200 m/s, it isn't gonna suddenly do 1200 just by using all three axes together.

My carrier gets nearly 600 kN stationary thrust with just 20 large reaction wheels. It looks to me like his engine may use more than that, AND get sqrt(3) times more torque from each.

Even at 23.7 m/s it can get 455 kN.

Gy0tuyU.png

Edited by Pds314

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1 minute ago, Pds314 said:

Nice! Although keep in mind he started with a plane / giant egg with a tail and a prop that was supersonic.

My carrier gets nearly 600 kN stationary thrust with just 20 large reaction wheels. It looks to me like his engine may use more than that, AND get sqrt(3) times more torque from each.

His advice is a great way to add up to ~77% without adding a lot more mass

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On 4/21/2019 at 1:53 PM, Pds314 said:

The goal of this challenge is to reach the Island Runway in a stock propeller aircraft, land, turn around (you MUST turn around, exiting the runway facing 180 degrees from how you landed on it, though you may do so at any speed and do not need to stop on the runway), and get back to the KSC runway, where you must land and stop.

Complete the course in as little time as possible.

Okay new rule on fastest times: I'm not gonna put multiple runs of related development by the same person on the list. So clearly-unrelated planes can get one person multiple entries on the list but not just derivatives or multiple runs of the same aircraft with minor tweaks. I'll just mark the fastest run.

Fastest times:
1. Chargan in the The Polar Bear Express: 7:23
2. Pds314 in the Turboelectric Racer III: Pfailure Edition: 8:02
3. Pds314 in the Oof 1: 10:03

Just asking : Can participants use jet engines to spin the propellers (i.e Jets pointing directly towards the 'sail' that makes the prop spin, not even a slightly pointing backwards that produces thrust).

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Posted (edited)
On 4/22/2019 at 4:12 AM, chargan said:

I like it. Naming this The Polar Bear Express. Added 50% more powah and fiddled with the prop angle in-flight. Managed 7:23

https://imgur.com/a/HoVvRbX

Prop angle is absolutely critical in maximizing the thrust from props.  I put together this chart using the plane featured in my video linked by pds314 above.  This data was generated by flying the "river racing" prop plane featured at the end of the video as level as I could at 100 meters.  The data demonstrates dramatic consequences from small changes in the angle of the propeller blade.
https://imgur.com/sMl3EYZ
https://youtu.be/J7oc1FLnWlY?t=689

Forward velocity reduces the angle of attack of your propellers.  As a result, as your velocity increases, the optimal propeller blade angle increases (see my data above!).  Below is the picture I used in my video for demonstration.
https://imgur.com/sISIQWf

Edited by EvermoreAlpaca

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Posted (edited)
On 4/22/2019 at 8:46 AM, FahmiRBLXian said:

Just asking : Can participants use jet engines to spin the propellers (i.e Jets pointing directly towards the 'sail' that makes the prop spin, not even a slightly pointing backwards that produces thrust).

I never said no turboshaft engines so yes. Although from my experience the power/weight of turboshaft engines is broadly inferior to that of optimized electrical ones. Not to mention that the torque on the aircraft is extraordinarilly high compared to electrical engines using magitech reactionless torque wheels.

Keep in mind however you shouldn't use the jets to generate net thrust. "Race the the Island on Juno Power" is a completely different category than turboshaft engines.

Edited by Pds314

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Posted (edited)
12 hours ago, EvermoreAlpaca said:

Prop angle is absolutely critical in maximizing the thrust from props.  I put together this chart using the plane featured in my video linked by pds314 above.  This data was generated by flying the "river racing" prop plane featured at the end of the video as level as I could at 100 meters.  The data demonstrates dramatic consequences from small changes in the angle of the propeller blade.
https://imgur.com/sMl3EYZ
https://youtu.be/J7oc1FLnWlY?t=689

Forward velocity reduces the angle of attack of your propellers.  As a result, as your velocity increases, the optimal propeller blade angle increases (see my data above!).  Below is the picture I used in my video for demonstration.
https://imgur.com/sISIQWf

*wonders if we will see an under-5-minute run with your Mach 4 racing egg thing.*

Edited by Pds314

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I made a crappy copy of it. Needs work obviously, but I think over a short run It's too fiddly to be worth it. By the time you get it running at optimal blade pitch etc. you need to land and turn around.

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Will give this a go. Don't expect much because my engines are generally unreliable and have never reached more than 110 m/s. The relatively simple stayputnik structural fuselage thermometer bearings that i make will often behave in unpredictable ways....

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6:29 but damaged the props landing back at the KSC. Hope that still counts. I think this is the best I can do with this core design.

How do you design bearings that can handle more torque? I'm using rcs bearings wrapped in 14 thermometers and it can handle 8 medium reaction wheels max. More than that and it tears itself apart.

https://imgur.com/a/UGV2Gmo

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