Mk2 Pod melts too easily

[MrMeeb]

Hey guys

Last night, I decided to have a stab at making another SSTO, pictured here:

While she can fly to orbit (just), I've found that the Mk2 cockpit overheats waaaay too easily, meaning I cannot pickup more speed in the atmosphere, forcing me to be less efficient. Do any of you know any solutions around this problem? I've been able to hit around 1500m/s at 15,000m, but anything faster and the thing melts.

Thanks!

(I should add that the photo shows Alpha in her current configuration, in which she's designed to be an SSTO for Laythe, hence the presence of VTOL engines for landing. She can do Laythe with ease, but I'm curious about heat tolerances for Kerbin)

[Streetwind]

I am by no means a plane expert (more like, the contrary), but my default solution here would be to pitch up and switch to rockets. Gain more altitude at the same time you're gaining more speed, so that the heat load balances out.

 

Edited April 24, 2016 by Streetwind

[MrMeeb]

3 minutes ago, Streetwind said:

I am by no means a plane expert (more like, the contrary), but my default solution here would be to pitch up and switch to rockets. Gain more altitude at the same time you're gaining more speed, so that the heat load balances out.

Well that's the thing with SSTOs - that's exCtly what you do. However you're supposed to build up as much speed as possible before doing so, and I think I've got more kick that I can't use 

[Streetwind]

1 minute ago, MrMeeb said:

Well that's the thing with SSTOs - that's exCtly what you do. However you're supposed to build up as much speed as possible before doing so, and I think I've got more kick that I can't use 

Can you even get much more than 1500 m/s on airbreathing nowadays though? Even RAPIERs ought to be losing thrust like a rock sinking into the ocean at that point. At least that's my limited experience... that number is kind of a breakpoint.

Edited April 24, 2016 by Streetwind

[MrMeeb]

25 minutes ago, Streetwind said:

Can you even get much more than 1500 m/s on airbreathing nowadays though? Even RAPIERs ought to be losing thrust like a rock sinking into the ocean at that point. At least that's my limited experience... that number is kind of a breakpoint.

It's quite possible I'm not remembering right...maybe 1100-1200?  

[Nich]

Switch to the inline cabin and a shielded docking port and you can get 1650 fairly easily

[MrMeeb]

2 minutes ago, Nich said:

Switch to the inline cabin and a shielded docking port and you can get 1650 fairly easily

Interesting...tbh I personally think I'm well within my rights to tweak the MaxTemp if that option is viable. I would've thought the mk2 could do similar things so

[Nich]

Mk2 has a pointy nose which causes lots of heat transfer. Shielded docking port causes flow separation and more drag to keep heat transfer to the ship a minimum.

[Foxster]

Just a left-field idea here: try putting a Communotron 16 antenna on the front like this...

Not sure it will work but it has often helped me in the past with problems like this. If nothing else, it will look cool

Edited April 24, 2016 by Foxster

[AeroGav]

The higher you go , the faster you can be without overheating.  Of course, as you get higher, the Rapiers will also lose power, so your top speed will be lower.  Looking at the config file, it seems the power really starts to fall off a cliff above mach 4.5,  so i generally aim for mach 3 to 3.7 at 20km, then try to be in a very shallow climb and accelerate to near mach 4.5.   After that I climb as high as possible without loosing speed.   When speed starts to decline, switch mode or if you 've got separate NERV engines or something, start those.

If you bring up the Alt f12 debug menu, go to Physics then Aero tabs, and check the "display aero forces gui" box , you get a nice set of stats including total drag and total thrust.  when you're no longer thrust-positive, time to go nuclear.

[ForScience6686]

My thoughts are you should be higher up in the atmosphere at those speeds.  I would use a higher climb rate instead of re designing.

[Nich]

On 4/24/2016 at 5:06 PM, ForScience6686 said:

My thoughts are you should be higher up in the atmosphere at those speeds.  I would use a higher climb rate instead of re designing.

That is true I normally hit 1650 around 21km