Whiplash-pre engine cooler(1 or 2?)

[JetGoFast]

Backstory-

I have been playing KSP for a little while now and have to try to achieve the fastest speed possible with only jets. I have encountered multiple issues as I have worked on this little project and now coming to the great source of knowledge known as Internet. 

Problem-

As you travel faster you heat up and as you heat you go higher to receive less friction from the atmosphere. This generates problems with the whiplash jet engine as it needs cool air to produce the maximum amount of thrust. By placing a pre-engine cooler before the engine it helps deal with the air/cooling problem, my question is-

Does the Pre-engine cooler affect the parts immediately touching it or Does it cool whatever engine is attached to the whole column of parts?

Does the pre-engine cooler act as an extension of the engine or a bonus? That is to say, can you place 2 or 3 pr-engine coolers in a row and have them affect one engine? Can you use the Split fuselage connector to combine two rows of coolers to affect one engine? What is 42 and how do we get there? Please help me understand.

 

Yours truly,

              guy

 

 

[Zacspace]

if I recall correctly, the pre-cooler part doesn't actually do any cooling and is just an intake. The wiki suggests it has slightly better thermal transfer and heat radiation than other comparable parts, but it's not something you can rely on to manage the thermals of an aircraft.

As far as I know, the performance of a jet engine in KSP only takes speed and atmospheric pressure into account and intake air heat isn't directly modeled.

[Snark]

Unrelated to your specific query here, just a side comment if you're trying to build jets for maximum speed: have you experimented with finding the right AoA (angle of attack) for your wings? I won't go into details here, because it's a whole lengthy discussion in its own right, is a bit off topic from your question, and maybe you're already on top of this. But the TL;DR is that you want to give your wings just a very slight tilt, not just attach them perfectly flat (which is the default behavior in the editor).

I just mention it in case it's not something you've been aware of.

[swjr-swis]

20 hours ago, JetGoFast said:

Does the Pre-engine cooler affect the parts immediately touching it or Does it cool whatever engine is attached to the whole column of parts?

The description text is somewhat misleading: it does nothing with the intake air. That particular part does have a small bonus in drawing off heat and radiating it away, but to be noticeable it needs to be directly attached to the engine (or other part) you want it to affect.

 

20 hours ago, JetGoFast said:

can you place 2 or 3 pr-engine coolers in a row and have them affect one engine?

In a row, no, because then they're no longer directly attached. But you can attach multiple of them radially to some engines, and then they will all affect that engine. The key is attaching them directly, one way or another.

 

21 hours ago, JetGoFast said:

Can you use the Split fuselage connector to combine two rows of coolers to affect one engine?

Again, no, because then they would not be directly attached to the engine.

 

21 hours ago, JetGoFast said:

I have been playing KSP for a little while now and have to try to achieve the fastest speed possible with only jets.

If you're serious about achieving the fastest speed possible with only jets:

1. Go directly for the RAPIER, do not pass Go, do not waste time with any other engines.
2. Do some research into KSP engine atmospheric/mach curves. The way KSP works, the speed optima are in fact lower in the atmosphere.
3. Build with high-temp resisting parts - you will need them.
4. @Snark's advice on wing AoA is good, but if you're trying for the highest speeds I'd recommend using Big-S elevons as wings. You can 'deploy' them and regulate their AoA with the deployment slider, which will let you finetune the angle live as you fly. When first lifting off that angle needs to be higher, but once you're in the speedrun, you'll want to tune it down to the bare minimum to just stay in the air.

Good luck in your endeavours, and don't forget to post some progress reports! Screenshots and craft files... or it never happened.

[ColdJ]

@JetGoFast

Hi there. Good thrust to weight ratio with minimal parts and a simple design can give you the best results.

Is 1,523 metres a second fast enough for you? Try making this, it is very simple. It is built for speed not for landing, The cockpit survived and the pilot walked away from it. The shock cone actually has less resistance than a nose cone, 1 nacelle, 1 precooler, a whiplash and the smallest canards times 4.

Spoiler

 

 

Edited February 13, 2022 by ColdJ

[KerikBalm]

If you want the fastest jet speed possible, use rapiers, not a whiplash.

Spoiler

 

>1700 m/s easy.

Those planes weren't meant specifically for high speed atmospheric flight, but rather for lofting a 2nd stage up to high altitude and high speed, so that the send stage can get to orbit (on a 3x or more rescaled Kerbin) before the 1st stage falls back in the atmosphere.

The 1st stage does end up having a lot of wing area, and a lot of jet engines, and minimal fuel, so it ends up cruising fast and high on kerbin, but obviously if optimized for just fast flight on kerbin, it wouldn't be carrying around empty LFO tanks