I think i had heat damage disabled lol

IDK if this works with default settings

Haha confirmed working full stock full throttle

so.. that's one way to get the engines to work at a good altitude (just accelerate fast enough to throw yourself out of the atmosphere before they cut off)

The thrust and the efficiency from these things is beyond insane though. Rocket can't compare, but they need a kick to get towards mach 1+ if the TWR isn't high

Osmoses

Sweden5302 Posts

April 28 2015 09:49 GMT

#624

Are those infoboxes on the right and numbers at the top mods?

Cyro

United Kingdom20343 Posts

April 28 2015 09:51 GMT

#625

One mod^ ~ http://www.curse.com/ksp-mods/kerbal/222685-kerbal-engineer-redux

^vid from before, went a bit too fast (but not to worry, we are still flying half a ship :D)

15 TWR, holy shit those engines are strong

Epoxide

Magic Woods9326 Posts

April 28 2015 09:51 GMT

#626

On April 28 2015 18:49 Osmoses wrote:
Are those infoboxes on the right and numbers at the top mods?

Yes, Kerbal Engineer

Cyro

United Kingdom20343 Posts

April 28 2015 10:00 GMT

#627

I think you can totally make a launch platform using rapiers that could potentially throw huge payloads to the heights where you can take over with nuclear engines. The nukes are actually very efficient already by 40km-ish, but that plane gets to 100-200 easily if i fly straight up

Jetaap

France4814 Posts

April 28 2015 10:07 GMT

#628

Why wouldn't you used the advanced jet engines? They seem more efficient than rapiers for athmospheric use only.

Cyro

United Kingdom20343 Posts

April 28 2015 10:34 GMT

#629

They're like 20% more efficient, but there's no reason to care if they use 4% of your liquid fuel instead of 5%

Efficiency was the only advantage i saw from a quick glance, but it just doesn't matter when they're that efficient. The "inefficient" Rapier is 8x more efficient than nuclear engine as long as it has air

Jetaap

France4814 Posts

April 28 2015 10:45 GMT

#630

So that kind of works.. not extremely efficient but i like the way it looks :D

[image loading]

Cyro

United Kingdom20343 Posts

April 28 2015 11:00 GMT

#631

stenole

Norway869 Posts

April 28 2015 12:41 GMT

#632

Looking at the config files for the engines, the rapier performs better at high speeds and at high altitude. The atmosphere and velocity curves are slightly nicer. The advanced jet engine has the entries "machLimit = 2.5" and "machHeatMult = 6.0" whereas the rapier engine has the friendly comment "// no mach limit". The best use of the turbojet is probably as a launch booster and not as an SSTO engine.

Cyro

United Kingdom20343 Posts

April 28 2015 13:09 GMT

#633

My engines always seem to shut down around 15-20km (thrust just falls off to nothing) even if i use a ton of intake, i'm not sure why but it makes it very difficult to achieve orbit without accelerating to huge speeds in the low atmosphere

stenole

Norway869 Posts

April 28 2015 22:07 GMT

#634

The max thrust of all jet engines are heavily affected by atmospheric pressure and velocity. They will all gradually weaken at higher altitudes. At 20 km the rapier will have 9% of the thrust that it has at ground level if going the same speed.

Jet engines also have a velocity (meassured in mach) where they are able to provide the most thrust. For the rapier that is mach 3,75 where they are able to provide over 8 times as much thrust. At mach 6 they can't provide any thrust. More air intakes won't help (thankfully). I'm not sure how ksp calculates mach numbers. In real life sound travels slower at high altitudes compared to at sea level.

One problem that can arise because of the increased thrust of engines is that if you are going at a speed that will break your aircraft, the engines will also be reving up causing even more speed, heat and death... unless you are prepared for it and throttle down fast enough.

Cyro

United Kingdom20343 Posts

April 28 2015 23:51 GMT

#635

At 20 km the rapier will have 9% of the thrust that it has at ground level if going the same speed.

This is just removing intake stacking by making them useless because the engines don't work anyway. What altitude does rapier give max thrust on? just as low as possible?

IDK how to get to orbit if you don't switch engines at 15km~ I was switching engines at twice that height before

Cyro

United Kingdom20343 Posts

April 29 2015 06:06 GMT

#636

Did this earlier~ just experimenting. I had heat on 50% and it almost blew up, so would be useless full stock:

The boosters lasted a lot longer than i intended, i just wanted to get kickstarted to ~200-300m/s+ for the air breathing engines to kick in. In the end it was too fast, but i'm not sure if slowing it down would actually help.

I could take off with air breathing engines only and use them to throw it out of the atmosphere - it had 1.0 TWR without the liquid fuel boosters attached at 0m/s so i could just double up on the engines and it would probably be 1.5+TWR quickly rising far far higher with some speed.

No reason to use this over an asparagus rocket though. I can't figure out anything useful to do with air breathing engines aside from fly around atmosphere quite fast for a really long time >__<

Maybe you could make two planes with very very high TWR, strap a couple onto a payload and fly with them, decouple and have 3 pilot able craft. That seems pretty adventurous though

felisconcolori

United States6168 Posts

April 29 2015 07:00 GMT

#637

So, I managed to get to space in a plane. Despite many different candidates being theoretically viable, they all had heat-related achille's heels in at least one part. I then trolled the KSP forums and found two different very minimalist designs. The first blew up repeatedly when attempting to fly the profile described, or else the picture didn't give me enough information to adequately recreate it.

The second actually survived, but as I have the heat colors currently enabled, I can tell you it was a near thing for the shock air intake at the front. It's basically a shock air intake on a MK 1 inline cockput with two of the medium LFO+O tanks, a precooler, and a rapier engine. Delta wings on either side, on small delta wing with elevon for a tail, and some gear. It actually survived a 45 degree climb at full throttle until the rapier engine kicked over to rocket mode, at which point it then was a 0 degree horizontal acceleration until apo was up around 90k. Circularize, and in orbit. Haven't brought it back down yet, it's late.

It kills me that this survives, while a well thought out MkII space plane using Big-S strakes and delta wing never fails to have the strakes explode rapidly upon hitting 800 m/s at any altitude. (To say nothing of fast ram-air intakes turn yellow and fail.)

Ah well, more tomorrow.

Cyro

United Kingdom20343 Posts

April 29 2015 12:17 GMT

#638

I then trolled the KSP forums and found two different very minimalist designs. The first blew up repeatedly when attempting to fly the profile described, or else the picture didn't give me enough information to adequately recreate it.

I've copied several designs, a few very simple and found completely different behavior to what they described. One of them was literally an intake, a control part, a pre cooler, an engine and 3 fins in radial symmetry and it behaved so differently to what was described+screenshotted that i don't think it could have been down to user error, we were just playing two different games physically.

Maybe some people still have some mods enabled that mess with 1.0 physics

Jetaap

France4814 Posts

April 29 2015 19:54 GMT

#639

Landing a mun probe without SAS proved to be suprisingly stressfull but i made it without reloading :D (low tech missions are always a bit sketchy).
Next mission should to send a probe to minmus, maybe try to biome hop a little bit.. and then i'll start the interesting stuff with manned missions and interplanetary robotic missions!

stenole

Norway869 Posts

April 29 2015 22:57 GMT

#640

I think it is odd how in career mode, things start off relatively hard and then gets much easier. Not until you have struggled through the Kerbin system do you get your manouver node abilities, less restrictions on how big you can build, a runway that is actually flat, ability to asparagus stage, bunches more celestial bodies filled with cheap science and parts that are progressively much better than the ones your start out with.

I was a little dissapointed today after spending lots of time creating the ultimate air breathing recoverable single stage launch booster. It was tricky to get into orbit with the payload I had chosen, but I did it. After getting it to work, I tested it against a haphazardly put together liquid-oxi engine with a single tank which was done in less than 10 seconds with no planning or testing. The liquid-oxi booster beat my complicated air powered booster by 600 m/s of deltaV which not only gets the payload into orbit but almost sends it all the way to the Mun.