Fastest speed for a jet so far?

[Bert]

I'm curious what everyone else has been able to reach using jet engines and not rocket engines.

I've hit Mach 4.5 (1543.91 m/s was my highest recorded speed) but can't push beyond that yet. I'm unsure if it's a game engine limitation or my designs are lacking.

Has anyone else reached a jet speed higher than Mach 4.5?

[Bert]

Treflu님이 먼저 게시:

Daggers님이 먼저 게시:

Rapiers don't fall under "jet engines" in the build menu, so for this test I'm not using them.

I can pass Mach 8 using methalox engines.

I get it but they do have an air breathing mode so for me it counts

This is a thread about jet engines, therefore I'm only talking about that record.

Rapier engines can be another record.

[AlizeInSpace]

Mach 4.9 in level flight at 12,500 m, match 5+ in a dive. is pretty easy to hit so far with a plane I made In like 5 minutes.

[Bert]

Pfannkuchen1701님이 먼저 게시:

Mach 4.9 in level flight at 12,500 m, match 5+ in a dive. is pretty easy to hit so far with a plane I made In like 5 minutes.

I just fit a rapier engine to my plane and hit 1900 m/s at 100 meters, or Mach 5.5, but it's not a jet engine so doesn't fit the parameters of this test.

I don't find diving to be very effective at reaching top speeds, I seem to have the best results in level flight.

[AlizeInSpace]

Daggers님이 먼저 게시:

Pfannkuchen1701님이 먼저 게시:

Mach 4.9 in level flight at 12,500 m, match 5+ in a dive. is pretty easy to hit so far with a plane I made In like 5 minutes.

What engine are you using?

I just fit a rapier engine to my plane and hit 1900 m/s at 100 meters, or Mach 5.5, but it's not a jet engine so doesn't fit the parameters of this test.

I am using 2 Whiplash on a mk 2 build with a total craft mass of 16.5 t at takeoff. 1 large mk 2 fuel tank, 1 small mk 2, and 1 small cargo bay mk 2, bicoupler fuel tank for the engines.

[Bert]

Pfannkuchen1701님이 먼저 게시:

I am using 2 Whiplash on a mk 2 build with a total craft mass of 16.5 t at takeoff. 1 large mk 2 fuel tank, 1 small mk 2, and 1 small cargo bay mk 2, bicoupler fuel tank for the engines.

Interesting to see a similar speed on an aircraft that is more than twice the weight of mine with twice the amount of engines.

I'm using a single Whiplash, 6.97 tons at takeoff with a thrust-to-weight ratio of 1.901.

We might be hitting the upper limits of what jet engines are capable of but I think we can push a little bit further.

[AlizeInSpace]

Daggers님이 먼저 게시:

Pfannkuchen1701님이 먼저 게시:

I am using 2 Whiplash on a mk 2 build with a total craft mass of 16.5 t at takeoff. 1 large mk 2 fuel tank, 1 small mk 2, and 1 small cargo bay mk 2, bicoupler fuel tank for the engines.

Interesting to see a similar speed on an aircraft that is more than twice the weight of mine with twice the amount of engines.

I'm using a single Whiplash, 6.97 tons at takeoff with a thrust-to-weight ratio of 1.901.

We might be hitting the upper limits of what jet engines are capable of but I think we can push a little bit further.

Oh definitely. Just waiting for this patch to drop so I can tweak this thing a bit. Trim down some mass and see if I can do better. Hopefully, the SAS gets tweaked a bit. Losing some speed when it waggles a tiny bit.

[Treflu]

Pfannkuchen1701님이 먼저 게시:

Daggers님이 먼저 게시:

Interesting to see a similar speed on an aircraft that is more than twice the weight of mine with twice the amount of engines.

I'm using a single Whiplash, 6.97 tons at takeoff with a thrust-to-weight ratio of 1.901.

We might be hitting the upper limits of what jet engines are capable of but I think we can push a little bit further.

Oh definitely. Just waiting for this patch to drop so I can tweak this thing a bit. Trim down some mass and see if I can do better. Hopefully, the SAS gets tweaked a bit. Losing some speed when it waggles a tiny bit.

A soft fix for that is to manual decrease the authority of you control surfaces so they don't rip the aircraft apart, you need to dig through menus to get there, but it's there.

honestly the old menus for individual parts were so much better, even the fuel transport was better to a degree

[Lionheartwolf]

If this is some type of record breaking competition, it should probably have some perimeters. If there are, it might help if you said what they are. Either way you need more constants.

What is your altitude? Does it have to be on Kerbin?

Mach and altitude (or more specifically air flow) are intimately linked. One doesnt mean very much without the other.

M = v/c, v isn't your speed, it's your speed as it moves through a fluid (in this case the atmosphere.)

Mach 4.5 at sea level isn't the same as Mach 4.5 at 10,000 meters, or 70,000 meters because airflow is different at those altitudes. (which we understand, thats why engines stall at high altitudes.)

If you wanted to just increase the number for the sake of a bigger number you could just increase your altitude until you have very little atmospheric pressure, just to the point of stalling (or just find a planet with a thinner atmosphere).

Even then it doesn't necessarily come down to which engine has the most thrust, it could come down to which craft has the highest ceiling. A great example would be the F-14B's F110-GE-400 engines generating 30,200 lbf vs. The SR-71's JT11D-20 generating 32,500 lbf. While the two engines provide a relatively similar amount of thrust the SR-71 can almost triple the speed of the F-14B because the SR-71 was designed to have a much higher operational ceiling.

[XLjedi]

Meh... "Who can build the fastest jet" challenges typically devolve into discussions about what is a "real" or "not real" jet in the mythical (and ever-changing) physics engine of KSP.

Similar to who can build the best dogfighter (for a weapons mod) and the winner is a box with 50 wings.

[Bert]

The only parameter I set was air-breathing jet engines from the build menu (meaning no rapiers although I did provide my record for that as well).

I didn't see any speed advantage at high altitude in the current build of the game, in fact my plane is faster around 100 meters altitude and isn't able to pull in air above 7000 meters. I'm also only using a single engine but I see no reason why people shouldn't be allowed to use more.

Other than that I have no other parameters for this test at the moment. I want to see if anyone can report higher speeds than me with a provided screenshot.

[Bert]

XLjedi님이 먼저 게시:

Meh... "Who can build the fastest jet" challenges typically devolve into discussions about what is a "real" or "not real" jet in the mythical (and ever-changing) physics engine of KSP.

Similar to who can build the best dogfighter (for a weapons mod) and the winner is a box with 50 wings.

If people are allowed to compete for the record of land speed I see no reason why we can't do the same for jets in the air.

It's just a game.

[AlizeInSpace]

Obligatory Screenshot.
https://imgur.com/a/CFxF0Yz

and craft file can be found here. Just copy the text from the link and paste it in the VAB and the plane will appear. Cool feature they added.

Plane Text File: https://drive.google.com/file/d/1O7y1ugLqPQiQrBLS4jb67nYCojAqQpKy/view?usp=sharing

[Bert]

AlizeInSpace님이 먼저 게시:

Obligatory Screenshot.
https://imgur.com/a/CFxF0Yz

and craft file can be found here. Just copy the text from the link and paste it in the VAB and the plane will appear. Cool feature they added.

Plane Text File: https://drive.google.com/file/d/1O7y1ugLqPQiQrBLS4jb67nYCojAqQpKy/view?usp=sharing

Nice. I'm confused why my build isn't able to pull air in at that altitude. I get compressor stalls above 7000.

[AlizeInSpace]

Daggers님이 먼저 게시:

AlizeInSpace님이 먼저 게시:

Obligatory Screenshot.
https://imgur.com/a/CFxF0Yz

and craft file can be found here. Just copy the text from the link and paste it in the VAB and the plane will appear. Cool feature they added.

Plane Text File: https://drive.google.com/file/d/1O7y1ugLqPQiQrBLS4jb67nYCojAqQpKy/view?usp=sharing

Nice. I'm confused why my build isn't able to pull air in at that altitude. I get compressor stalls above 7000.

Since the patch, I get compressor stalls as well. I tried multiple combos but had little success, and the stability of my plane went down the toilet as well. It was rock solid and I could fly it steady until I ran out of fuel. This patch did not help and with all the other problems I'm still seeing like my mother ship orbit randomly changing while I'm on the planet in my lander, I will just shelve this for a while. These devs are just incompetent.

[AlizeInSpace]

AlizeInSpace님이 먼저 게시:

Daggers님이 먼저 게시:

Nice. I'm confused why my build isn't able to pull air in at that altitude. I get compressor stalls above 7000.

Since the patch, I get compressor stalls as well. I tried multiple combos but had little success, and the stability of my plane went down the toilet as well. It was rock solid and I could fly it steady until I ran out of fuel. This patch did not help and with all the other problems I'm still seeing like my mother ship orbit randomly changing while I'm on the planet in my lander, I will just shelve this for a while. These devs are just incompetent.

I rebuilt the craft in a new save and the air intake issue is fixed. Stability is mostly fine considering SAS is worse than before. I managed to breach mach 5 at level flight for a few moments though.

Screenshot:
https://i.postimg.cc/43FgC7Db/X-1a.png

Craft File. Copy the text and paste it into the KSP 2 VAB:
https://drive.google.com/file/d/17kt0dVOxgYmcHjXSDaHuhrkHhcydOEmS/view?usp=sharing