10% machingbird

[Pds314]

This challenge is to build, takeoff, fly, and land an airbreathing aircraft on just 10% thrust limiter The goal is to go as fast as possible.

Rules

0. No engine shall exceed 10% thrust limiter in any mode or any phase of flight.

1. Top Speed should be in level flight. Not a dive.

2. No parachutes.

3. The aircraft should land in flightworthy condition.

4. No alternative power sources. Jets only.

5. Aircraft must be crewed.

6. Decoupling engines is forbidden.

 

Categories

There will be three categories:

1. Bypass

May use Juno, Goliath, Wheesley, Panther (dry mode only) engines.

2. Afterburning

May use all jet engines. R.A.P.I.E.R.s must be open cycle only.

3. Cruise missile

As Afterburning, but uncrewed, multi-stage, or unlandable designs are allowed. This is basically the anything goes category. I.E. rule 2, 3, 5, 6 don't apply.

Leaderboards

Bypass
1. 236.3 m/s:   Pds314 in the Object B1024 "Baby Ox"

2.

 

Afterburning

1. 1686.2m/s: Lt_Duckweed

2. 845 m/s 581 m/s:   Pds314 in the SupersonX 1

3.

Edited September 4, 2020 by Pds314

[doggonemess]

This sounds fun. Would the cruise missile category be allowed a rocket assist takeoff? Wouldn't this go against rule #6?

[Pds314]

9 hours ago, doggonemess said:

This sounds fun. Would the cruise missile category be allowed a rocket assist takeoff? Wouldn't this go against rule #6?

No rocket assist. Also the cruise missile category violates rule 6. Any multi-stage design is allowed as long as rockets are not used.

[Pds314]

My own attempt at the bypass category. I didn't even get all that close to mach 1.

236.3 m/s in the Object B1024 "Baby Ox"

I cannot stress enough how important having positive AOA built into the wings is. With no other changes at all, a 5 degree AOA added on the wings got this plane an extra 44 m/s. A 23% improvement for an often overlooked change. Body AOA drag is a very significant factor. Even adding a 5 degree pitchdown deployment on the horizontal stabilizer and compensating with reaction wheels got several m/s improvement.

[Pds314]

In the afterburning category:

I managed 581 m/s before running out of fuel in the SupersonX 1!

I definitely could go faster in this airplane. Especially if I give it drop tanks or extra fuel. Or replace the fuselage with fuel. Perhaps surprisingly, it can't quite break Mach 1 at sealevel.

Edited September 4, 2020 by Pds314

[Pds314]

SupersonX 1, flight 2:
845 m/s!

I did another run in the same aircraft. Managed to break 800 m/s over the panhandle. At first I overran my optimal altitude and was stuck in the 700s above 17k but then I managed to get back down and start accelerating again in level flight.




Getting down is a bit tricky. I don't want to do some straight vertical dive and somehow lose the aircraft trying to pull out, but I don't want to spent too much ec on the way down keeping it stable, so I shut down all but one reaction wheel until I drop below 1000 meters.

[Lt_Duckweed]

Managed to reach 1686.2m/s at 21.86km. Craft does NOT want to take off easily and I had less than half of a kn of spare thrust leaving the runway, but it could, so there is probably room for optimization by reducing wing area and taking off from the flats around the ksc rather than the runway itself.

EDIT: Woops, forgot to land it, let me do that real quick.

Edited September 4, 2020 by Lt_Duckweed

[Lt_Duckweed]

Landed!

[Pds314]

5 hours ago, Lt_Duckweed said:

Landed!

Wow that's really fast. Considering that R.A.P.I.E.R. engines stop at Mach 6 and up there the speed of sound is about 299 m/s, which would put the maximum possible at around 1794 m/s.