Flying in 1.0 super fast and fatal.

[zenopath]

I am of the opinion that something is wrong with the new aerodynamics model...

Particularly, the current thrust to weight ratio needed to break 1km/s is pretty pathetic. 1g thrust is enough to hit that barrier, and problematically, 1km/s is always fatal for your plane.

It seems to me that while the game models correctly while gaining altitude, if you put your plane in a strait flight, it will start gaining speed at a ridiculous rate. Then it will hit that 1km/s mark and explode.

Anyone else experience simular results?

[Enorats]

Very much so. I used to use spaceplanes almost exclusively in .90 (literally had entire games where I never launched a rocket) but I can't get anything into orbit anymore. They just burn up far, far too easily at the speeds and altitudes required to make orbit.

[X-SR71]

Bring the soup back!

[juanml82]

I'm not sure that means something is wrong, from a pretense of realism, with the model. If you stick a powerful enough engine to a light enough aircraft in the real world, I don't see why it shouldn't reach match 3 fast - missiles do this, in fact. The problem then becomes one of overheating, which is a real problem for every real life attempt at building match 3 aircraft

[Radam]

Look at it this way, you have very good engines.

Only thing you have to do is throttle down...

[Jovus]

I'm not sure that means something is wrong, from a pretense of realism, with the model. If you stick a powerful enough engine to a light enough aircraft in the real world, I don't see why it shouldn't reach match 3 fast - missiles do this, in fact. The problem then becomes one of overheating, which is a real problem for every real life attempt at building match 3 aircraft

Well, excepting that you're talking about ramjet (and even scramjet) territory with those speeds, instead of just turbojets, yes. But every plane designed to fly at those speeds uses very special materials in order not to tear itself apart.

[Enorats]

Realism is beside the point here tbh. The gameplay is suffering because our planes can't reach the speeds necessary to properly fly. Sure, I can throttle down or fly higher and all that.. but getting one into orbit requires a good deal of flying quickly in fairly thick atmosphere to get a running start. That running start into orbit is currently melting parts all over the plane randomly. By the time I get there, my air intakes, RCS ports, and tail fins are always missing.

[Robotengineer]

It's not the aero, it's the engines. Until they fix the engines I would recommend throttling down.

[Commander Jebidiah]

Not to sound like a [snip] here but stay below 1km/s while below 23km. It should be obvious, I dont let my rockets go above 1km/s while below 25km.

Edited April 28, 2015 by Vanamonde

[Radam]

Really, dont like powerfull engines? At least something we got with ISP nerf for rockets.

[panzer1b]

What i hate about new jets is they nolonger work well at high altitudes (as in completely die off). At least rapiers will get you up to 1.4km/s before you eject into orbit.

My newest SSTOs use a very odd ascent profile, basically 45 degrees to 5km, level off, increase speed as much as u can without frying, and then gun your ions, nukes, or whatever space engine you choose to work with.

[allmhuran]

I'm actually trying to hit 1400 m/s at around 20,000m. So far my maximum is 1382. Use a lot of precoolers and for additional safety put a Mk1 pod on the front instead of a spaceplane part. Spaceplane parts will get you up to almost 1200 m/s but have 400K lower heat tolerance than the Mk1 pod.

Overall, though, I do agree. The thrust curves are wacky.

[The DigitalAlchemist]

It's not impossible, it just takes a lot more finesse than it used to. You cant just lob the thing into orbit, or start accelerating to orbital launch velocities at 15km anymore.

What I usually do is take a 45* trajectory up to around 10km, level out and accelerate up to around 550m/s then start carefully pitching back up to around 20-25* keeping an eye on my thrust and watching out for heating effects. I keep carefully pulling back to increase my vertical speed until i'm around 45* or so. By the time I reach 30km I'm generally traveling 850-1000 m/s, then I switch my rapiers over and keep accelerating until my apoapsis hits 70, then right before I hit the peak I accelerate into orbit.

I'm not even that good but after I understood the new mechanics I found it pretty easy. This here is my proof that I did it. Of course there's plenty of refinement I need to do, but I did a full round trip to space, orbit, de orbit and landing.

Coming down was a bit tricky and took a couple attempts but after 2-3 tries I understood what I needed to be doing to bring her back down safely, and eventually got her on the ground again.

[mikegarrison]

I know some of you guys got used to being able to achieve orbit using jets (or, god help us, just wiggling your control surfaces), but JETS CAN'T TAKE ANYTHING TO ORBIT. Come on, of course jets flame out when there is no air. That's why real space planes use rockets.

It's also very rare in real life for planes to have TWR >1. Instead of complaining that you go too fast at full throttle, why not just throttle down?

There is a huge gameplay issue trying to model something like Spaceship 1, but it's not that jets can't take an SSTO spaceplane to orbit. The real gameplay issue is that you can't have a mothership in atmosphere unless you are willing to discard it, because you can't both land the mothership and orbit the daughter spaceplane. It would be cool if KSP would allow you to freeze time and fly both ships from the point of separation, one after the other.

[allmhuran]

On all the craft I've tried the jets die at about 26,000m (or the intakes explode). But I'm just going for flight speed, not orbit. Precoolers survive much longer but don't provide as much air.

[Kami_K220]

What i hate about new jets is they no longer work well at high altitudes (as in completely die off). At least rapiers will get you up to 1.4km/s before you eject into orbit.

If jets actually worked well at ridiculously high altitudes we would already have real life SSTO's. Problem is air breathing engines need air to work and as you get higher the air becomes less dense. less dense air means less air to accelerate behind you meaning less thrust.

I for one am glade to see it is a lot more challenging to get a SSTO to work as now we have similar challenges to those actually making them IRL.

As for the 1000km and boom, this also makes sense. I'm pretty sure we have engines today that have the ability to do this but the people using them understand the concept of aerodynamic stress and heat and keep well within the aircraft's structural envelope. Exploding planes = a bad day at the office.

[bwheatley]

I know some of you guys got used to being able to achieve orbit using jets (or, god help us, just wiggling your control surfaces), but JETS CAN'T TAKE ANYTHING TO ORBIT. Come on, of course jets flame out when there is no air. That's why real space planes use rockets.

It's also very rare in real life for planes to have TWR >1. Instead of complaining that you go too fast at full throttle, why not just throttle down?

There is a huge gameplay issue trying to model something like Spaceship 1, but it's not that jets can't take an SSTO spaceplane to orbit. The real gameplay issue is that you can't have a mothership in atmosphere unless you are willing to discard it, because you can't both land the mothership and orbit the daughter spaceplane. It would be cool if KSP would allow you to freeze time and fly both ships from the point of separation, one after the other.

There is a mod that lets you to detach a child ship and then it will pause the mother ship and let you fly both back. I forget the name of it..scott manley did a video on it.

[nilof]

Real life jet aircraft were never thrust limited, the bottleneck has always been aerodynamics and heating. Practical supersonic flight became possible due to the discovery of the area rule. After that it was limited by materials technology due to heating issues.

Getting into orbit is still very easy with rapiers. Even without them, the stock aeris 4A gets into orbit with a lot of margin assuming a proper flight profile.

Edited April 28, 2015 by nilof

[Enorats]

It's not a matter of jets not getting to orbit. Of course those don't work in real life, and they shouldn't here. The problem is that in KSP space planes generally get to a high altitude and then accelerate to ~1400 m/s just before the atmosphere starts to thin out, then lift the nose a bit and swap to space engines (swap to nukes and/or RAPIER modes). This just isn't working anymore because jet engines seem to be flaming out much earlier and where they will operate you can't achieve the speeds necessary without melting your plane. The transition from jet to rocket is far more difficult than it used to be because we can't build up enough speed in atmosphere to safely exit the atmosphere and successfully switch over to rocket mode reliably and efficiently.

[FlipNascar]

I've hit 1,600 so far just on jets... This one isn't technically fully reusable as it uses a heatshield on the nose, then a tail adapater on the heatshield. Tail adapter takes a beating and explodes (but they're so cheap!) and I'm assuming with it, some stored heat...? It will sit there at 1,600 for a bit.... Must go faster.

[mikegarrison]

There is a mod that lets you to detach a child ship and then it will pause the mother ship and let you fly both back. I forget the name of it..scott manley did a video on it.

Really? I should have guessed somebody would do this.

The other way would be for the mothership to just "auto recover" immediately after separation, but while that would save your pilot and money, that wouldn't let you fly it.

[juanml82]

Really? I should have guessed somebody would do this.

The other way would be for the mothership to just "auto recover" immediately after separation, but while that would save your pilot and money, that wouldn't let you fly it.

The mod's name is FMRS IIRC. I'm not sure if it will work out of the box in 1.0, since it works with savefiles. In the old stock Aero, I couldn't make a mother/daughter ship work, though - the sister ship would be lacking control, but maybe that's on my kerbal construction skills. The other issue is keeping both ships aerodynamically stable both as separate vessels and as a combo.

It may be worth a try in 1.0. I wouldn't try it with a daughter ship in a cargo bay - who knows how it will react to being suddenly exposed to some 1,500 m/s

(makes a mental note of trying exactly that at some point)

[zenopath]

I don't know much about aerodynamics, but I am certain that modern jets have WAY more than 1g thrust. And that it takes more than 1g of thrust to break the sound barrier...

I have even noticed that once you begin your strait flight, you can hit 1km/s even if you reduce thrust to like 10%... so at 1m/s of thrust, my plane is acellerating at something like 50m/s squared all the way up to 1km/s ... sorry but the math doesn't add up

[Starwhip]

I don't know much about aerodynamics, but I am certain that modern jets have WAY more than 1g thrust. And that it takes more than 1g of thrust to break the sound barrier...

I have even noticed that once you begin your strait flight, you can hit 1km/s even if you reduce thrust to like 10%... so at 1m/s of thrust, my plane is acellerating at something like 50m/s squared all the way up to 1km/s ... sorry but the math doesn't add up

I think you mean 1 kilonewton... There's a big difference.

1 newton = 1 kilogram @ 1 m/s^2. 1 kilonewton = 1 kilogram @ 1000 m/s^2 or 1000 kilograms at 1 m/s^2, or somewheres in between.