Cockpit burns up during reentry

[Gordon Fecyk]

10 hours ago, AeroGav said:

Inspired by your example I've started a career game with Ferram Aerospace , Real Fuels, Real Engines and Advanced jet engine.

Beauty!

When I started the AEK story, I thought long and hard about add-ons and feedback from potential subscribers. Figured I'd get the best experience from flying 'properly,' even if the technology was not entirely realistic. It seemed especially strange to need to 'flair out' before landing a plane in stock KSP in order to reduce speed.

Glad to see you've quantified what I could only understand empirically, regarding upper atmosphere drag. I still can't bring enough fuel up to low orbit to make Minmus with a single Panther, but now you've shown me why.

Back to making Mk1 cockpits work in space planes: Something else I've learned is, if you're going to 'unrealistically' transfer resources to balance-out a craft, one can hold a re-entry angle easier by watching the pitch input while SAS is on, then moving resources forward or back until pitch input is near zero. The balance needed will change depending on where your craft is on its descent path. This way you save battery power for your reaction wheels on descent while protecting that cockpit from overheating.

Some folks will mark the craft's centre of lift with some radial-mounted instrument like a thermometer, then match that to the centre of the screen as the camera focuses on the craft's centre of mass. I haven't mastered where CoM is on my screen though; if there's an add-on to mark the centre of the camera maybe get that.

[fourfa]

On 3/23/2017 at 7:05 AM, bewing said:

That's kind of the "point", actually. Blunt on ascent adds a little difficulty, because of the extra drag. But it also completely eliminates all your nose heating problems on ascent and reentry, because of the detached shockwave effect.

I find that a klaw on the nose works just as well for this.

To expand on this a little: I've been testing a particular craft for ages (~25t Mk2 SSTO Laythe sea/spaceplane where I can remove the wing module and stow in a Mk3 bay, rather complex to get right) with the shielded docking port on the nose for utility and thermal resistance.  It has so much drag that replacing it with the plain blunt nosecone yields an extra 800 m/s of dV leftover on reaching orbit from KSC.  800!  Just from the drag of that single piece.

In the balancing act of mission needs I got rid of the shielded docking port and put a docking port elsewhere, hidden from drag.  The plain nose cone, which has a higher thermal limit than some pieces, holds up fine with the ascent profile of this particular plane.  Just be aware the shielded port may be costing players more than is obvious.

[AeroGav]

54 minutes ago, fourfa said:

Just be aware the shielded port may be costing players more than is obvious.

It got increased in the last update i think - from a low drag to a rather high drag part - damit, i can't find that Russian guy's videos now where he did rocket races in 1.2.2 with different configs.    He should have been stickied !

[ajburges]

On 3/22/2017 at 11:58 AM, FloppyRocket said:

In Scott's video, the craft kept oscillating back to nose-forward because SAS was on Prograde.

Um, no.

It oscillated because he ran out of power. At angels 40, control surfaces offer little control authority. His control earlier was from reaction wheels in the cockpit. When he ran out of juice noting could maintain that AoA.

On 3/22/2017 at 11:58 AM, FloppyRocket said:

In Scott's video, the craft kept oscillating back to nose-forward because SAS was on Prograde.

Um, no.

It oscillated because he ran out of power. At angels 40, control surfaces offer little control authority. His control earlier was from reaction wheels in the cockpit. When he ran out of juice noting could maintain that AoA.

[EpicSpaceTravel]

Keep the ship at a angle so it slows down the speed and aero forces. So he was just at a bad angle.

[Jarin]

Okay, this has come up in multiple threads in the past couple days, so I really feel like I need to weigh in. There's nothing wrong with regular mk1 cockpit for re-entry. I just went back and tested this, throwing some rapiers on my old panther SSTO (because there's no kill like overkill) 

flight album here

Aggressive direct re-entry from LKO

No problems.

I do shed my heat in orbit with a thermal control unit, but even that's not necessary. I tested again without heat-dumping and got a bit toastier on re-entry, but a bit of intentional tumbling shed enough heat to keep from anything going boom.

I had more issues with overheating going UP than coming back down. 3 rapiers on this is about 2.5 two many, I think.

 

The problem with what everyone's suggesting? You're spending too much time in the upper atmosphere. You don't need a higher PE, you need a lower one. Hit the thick air sooner, and you shed speed before you build up too much internal heat. If your PE is positive on re-entry, you're just slow-cooking yourself.

Edited March 30, 2017 by Jarin

[Hodo]

I have found a minor work around for dealing with overheating cockpits.  

There are heatsinks in the parts, if you place them in a way that does not interfere with your aerodynamics it and turn them on, they will vent a great deal of heat as you come in or go out.  

I think you can just barely see them on the bottom of the nose of this craft.  I have two, one on either side.  

[Spricigo]

15 minutes ago, Hodo said:

 I think you can just barely see them on the bottom of the nose of this craft.  I have two, one on either side.  

I accept your word because I cant see it. Personally I had good results with the MK0 heat shield

[Hodo]

3 hours ago, Spricigo said:

I accept your word because I cant see it. Personally I had good results with the MK0 heat shield

You can see it here more clearly.