Aerospikes are darn good in 1.05.

[cephalo]

So I have been flying a new spaceplane that I plan to use on Jool, and I noticed that the new aerospikes are very good for Kerbin spaceplanes also. I'm getting to orbit with more dv to spare than a similar design with rapiers, without all the fuss of mode switching. It's basically like flying a rocket.

[NathanKell]

Well, the spike has a way higher vacuum Isp than the RAPIER, and by 20km you're effectively in vacuum as far as Isp is concerned...

[cephalo]

It also has very high thrust that doesn't depend on a particular airspeed. With rapiers you spend a good measure of fuel coaxing them up to speed. With spikes you just point at the sky at such an angle that you don't burn up.

EDIT: I wonder if the RAPIERS sweet spot in terms of speed/air density is in a band that is too dangerous in terms of overheating. 900 kN of thrust is only useful if it doesn't fry your plane.

Edited December 3, 2015 by cephalo

[Guest]

I never used the aerospike, and now I do all the time.

[fourfa]

Nothing changed in the specs of the aerospike in 1.0.5 AFAIK... the rear attachment node is very convenient, but there were functional ways around that at the cost of a couple parts.  The atmosphere has changed some though.

I love them for spaceplanes purely for the short rear overhang, and they just look dang cool on the back of a tapered profile

[panzer1b]

3 hours ago, cephalo said:

I wonder if the RAPIERS sweet spot in terms of speed/air density is in a band that is too dangerous in terms of overheating

This is my big problem with 1.0.5, the fact that rapiers really shined at getting a plane to 1600m/s, and from there you didnt even need a drop of LFO but could nuke your way to orbit.  Now, the absolute max ive managed to pull off is ~1400m/s, which is below the threshold where nukes can bring you to orbit alone.  All in all, rapiers used to be the go-to engine for anything and everything space related since you could achieve much higher speeds (provided your plane wasnt excessively draggy or badly designed) then the turbojet gave you.  Now with 1.0.5, its is still a far better engine for SSTOs, but it is nolonger cut and dry since your speed is still roughly capped at ~1350-1400, and the turbojet can get you to 1250 if you do it right, and it burns less fuel to get you to said speed. 

Ive found teh aerospike+turbojet to be a very efficient combo, and it looks really cool too to have a aerospike clipped inside a whiplash or panther (although noone would use panther for SSTOs unless its career and no other choice since that engine cant really break 1000m/s reliably nor get you to a high altitude).  The aerospike is now one of my go-to engines after it was buffed to 1t mass (used to be 1.5t back when), so unless its a very light purely vaccum craft, where i use a 909 instead, or interplanetary/pure space and heavy, where i use a nuke, its aerospike all the way.  1.0.5 seems to have made the aerospike a very dominant engine in terms of a very good combo of TWR being up there with engines like the LVT-30, very good ISP (for a LFO engine), low mass (1t is pretty low given its thrust and isp), and also small size (easier to do something with it on unconventional designs, better for landers, ect).

Overall what i use the aerospike for is almost anything that is designed to land on planets or fly around in atmo where a jet wont work (due to oxegen levels).  It remains useful even on Eve (although 1.0.5 has killed off Eve for any real fun craft since its now so hot there and impossible to do jack without heat shield spam), and well, its my main duna engine of choice (nukes can do it on duna too but they are just annoying to land/take off with).  Its a exceptional engine, and aside from the obvious nuke beats every single alternative in space itself, the aerospike has become my 4th most common space based engine (after the nuke, rapier, 909).

[wrcsubers]

6 hours ago, cephalo said:

EDIT: I wonder if the RAPIERS sweet spot in terms of speed/air density is in a band that is too dangerous in terms of overheating. 900 kN of thrust is only useful if it doesn't fry your plane.

These are (roughly) the Velocity and Atmosphere curves that the RAPIER in Air-Breathing Mode uses.  How you calculate Thrust output goes like this:

Engine Max Thrust * Thust Multiplier(at given velocity) * Thrust Multiplier(at given atmosphere density) = Actual Thrust

So for the RAPIER: 105 * 8.5(maximum thrust multiplier velocity value) * 1 (maximum thrust multiplier atmosphere value) = 892.5KN of Thrust

Keep in mind that this is with the maximum atmosphere multiplier which starts to decrease above ~600m in altitude.

You can kind of see where the engine works best and for the RAPIER it's very dependent on your velocity.

[Nefrums]

7 hours ago, panzer1b said:

This is my big problem with 1.0.5, the fact that rapiers really shined at getting a plane to 1600m/s, and from there you didnt even need a drop of LFO but could nuke your way to orbit.  Now, the absolute max ive managed to pull off is ~1400m/s, which is below the threshold where nukes can bring you to orbit alone. ...

Put a shielded docking port at the front of your ship and it will survive 1600m/s

[cephalo]

5 hours ago, Nefrums said:

Put a shielded docking port at the front of your ship and it will survive 1600m/s

See, that's the problem here. It's not the RAPIER, it's that nose cone technology hasn't kept up.  Too bad we don't have a shielded air intake.

EDIT: Actually there is a new inline air intake that seems pretty good. That should go well with the shielded docking port on small planes, or possibly a small heat shield has less drag than the docking port.

Edited December 4, 2015 by cephalo

[panzer1b]

7 hours ago, Nefrums said:

Put a shielded docking port at the front of your ship and it will survive 1600m/s

LOL.    Place a shielded port on the back of the nuke, and offset it so its in front of the craft, instant low drag solution which shields your entire vessel without the drag penalty of the shielded port.  Also just discovered another exploit, take a heat shield, drain ablator, place it behind a intake (such as the shock cone), and offset intake inside, heat shield blocks the heat entirely (and with ablator you can exceed 1600m/s now LOL!

 

Thanks alot for bringing back the good old days where i had 7000m/s dV in my starfighters!  Time to abuse these until they are patched!  it seems that the shield behind intake works wonders, everything gets white hot but nothing explodes going 1550m/s (need to redo the aerodynamics as i altered then for 1.0.5, time to go back to 1.0.4 superfighters!

Edited December 4, 2015 by panzer1b