Runway Land Speed Challenge (NO SRB)

[Galaxystar Kerman]

Description:

- Start and stop within the runway.

- Under 10 tons

- Under 123 parts

- No SRB(Solid Rocket Booster)〜said Jebediah Kerman

- Stock parts only

- No mod applied (E.g. TweckScale)

- No cheats

- Impress Jebediah Kerman

Let the challenge begin!

Edited March 15, 2019 by Galaxystar Kerman

[sevenperforce]

I've gotten a little over Mach 1 with a Vector for launch and a pair of Thuds for braking, but I haven't optimized much.

[Galaxystar Kerman]

A thousand of attempts finally got it with no Kraken! 442.7 m/s = 990.29 mph that's Mach 1.3!!!!

 

[sevenperforce]

4 hours ago, Galaxystar Kerman said:

A thousand of attempts finally got it with no Kraken! 442.7 m/s = 990.29 mph that's Mach 1.3!!!!

 

Impressive!

Have you tried removing a couple of parachutes, adding fuel to make up the weight difference, and using the wheelbrakes when you stage? Might be able to squeeze out a few more m/s.

[herbal space program]

I know they're not allowed for this challenge, but Sepratrons just blow everything else out of the water on this. The only LF engine that can touch them is the Vector, but it falls way short.

...Wait, it has to STOP on the runway too? Hmm...

Edited March 14, 2019 by herbal space program

[Galaxystar Kerman]

7 hours ago, herbal space program said:

I know they're not allowed for this challenge, but Sepratrons just blow everything else out of the water on this. The only LF engine that can touch them is the Vector, but it falls way short.

...Wait, it has to STOP on the runway too? Hmm...

Yes it has to stop on the runway ( - Start and stop within the runway. ) I'm trying to get a better design but seem like Vector engine is a best bet but with a dead weight of 4 tons O_O. Might have to use decoupler to get rid of dead weight to stop quicker

[Galaxystar Kerman]

18 hours ago, sevenperforce said:

Impressive!

Have you tried removing a couple of parachutes, adding fuel to make up the weight difference, and using the wheelbrakes when you stage? Might be able to squeeze out a few more m/s.

Well... removing more parachutes make the vessel take longer to stop and adding more fuel make the engine run longer which is good but the vessel depends on those high altitude parachutes to stop before running over the end of the runway... weight make the vessel take longer to stop, I might have to mess around with the decouplers to get rid of dead weight like Vector engine (4.0 ton) on the part of slowing down the vessel so i can add more fuels and use less parachutes hmm... gotta try that.

[sevenperforce]

9 hours ago, Galaxystar Kerman said:

 Vector engine is a best bet but with a dead weight of 4 tons O_O. Might have to use decoupler to get rid of dead weight to stop quicker

Trouble is that standard inline approach would have the vector slamming into the back of the vehicle if decoupled.

Could go with two parallel boosters and decouple tanks and engines alike at MECO but 10 tonnes is not much margin. Dart or clustered Sparks might be better.

[herbal space program]

2 hours ago, sevenperforce said:

Trouble is that standard inline approach would have the vector slamming into the back of the vehicle if decoupled.

Could go with two parallel boosters and decouple tanks and engines alike at MECO but 10 tonnes is not much margin. Dart or clustered Sparks might be better.

I'm thinking that the thing to do would be to exchange  the decoupler on the Vector for some batteries and reaction wheels, cut thrust for an instant at top speed,  maybe 2/3 of the way to the end, then flip around and go back to full throttle with the same engine. 

Edited March 15, 2019 by herbal space program

[Galaxystar Kerman]

2 hours ago, herbal space program said:

I'm thinking that the thing to do would be to exchange  the decoupler on the Vector for some batteries and reaction wheels, cut thrust for an instant at top speed,  maybe 2/3 of the way to the end, then flip around and go back to full throttle with the same engine. 

I did try decoupling Vector engine and it seems to work like I expected, it exploded right after I decoupled because of the whole vessel very close to the ground. I think I might have found other design that would go as fast as Vector. I’ll upload it when I get home. I have to try that 180° flip and throttle for breaking... 

Edited March 15, 2019 by Galaxystar Kerman

[Mr. Peabody]

On ‎3‎/‎13‎/‎2019 at 12:43 AM, Galaxystar Kerman said:

No SRB(Solid Rocket Booster)〜said Jebediah Kerman

You do know that the SRB is Jeb's favorite engine type, right?

Spoiler

 

[Galaxystar Kerman]

6 hours ago, The Dunatian said:

You do know that the SRB is Jeb's favorite engine type, right?

  Reveal hidden contents

 

Then explain this?https://imgur.com/a/e0F0mPd

[sturmhauke]

On 3/15/2019 at 8:46 PM, Galaxystar Kerman said:

Then explain this?https://imgur.com/a/e0F0mPd

That's obviously Bob, he hates everything.

[sevenperforce]

On 3/15/2019 at 2:32 PM, herbal space program said:

I'm thinking that the thing to do would be to exchange  the decoupler on the Vector for some batteries and reaction wheels, cut thrust for an instant at top speed,  maybe 2/3 of the way to the end, then flip around and go back to full throttle with the same engine. 

This was my very first approach and I found I could not execute the 180 without tumbling.

[qzgy]

1 hour ago, sevenperforce said:

This was my very first approach and I found I could not execute the 180 without tumbling.

Even with zero wheel friction or whatever?

Maybe an approach someone could try is having a fairing housing whatever retro rockets they carry. Deploy the fairing, fire the rockets. No flipping needed. Of course, might take longer and the rockets add excess mass.....

[herbal space program]

39 minutes ago, qzgy said:

Even with zero wheel friction or whatever?

I was definitely thinking that would be part of it,  as well as some strategically placed chutes to be deployed during the turnaround maneuver. I might also disable the pitch on the reaction wheels, so that when I hit the retrograde lock button, the craft can only yaw to turn around.

Edited March 19, 2019 by herbal space program

[Aeroboi]

On 3/13/2019 at 5:43 AM, Galaxystar Kerman said:

snip

- No SRB(Solid Rocket Booster)〜said Jebediah Kerman

snip

Meaning no sepatrons? (uses solid fuel)

[sevenperforce]

17 hours ago, Aeroboi said:

Meaning no sepatrons? (uses solid fuel)

Indeed