Are the smallest antennas overpowered on space planes?

[Sresk]

So the other day I read a tip about putting the smallest antennas on the nose of your space planes to help with heating problems on re-entry.

The other comments seemed to take it in stride as a kerbaled aerospike (not to be confused with the rocket) see here https://en.m.wikipedia.org/wiki/Drag-reducing_aerospike.

So I tried it out and holy$*!@. I pushed an SSTO to over about 1400m/s at 20k and blew up due to heating. Put spikes on the nose and the 4 ram intakes and pushed that same exact plane to over 1700 m/s at 20k feet before jumping off to space.

I then returned that plane from minmus by setting my peri at 15k and went screaming in from orbit at over 3300 m/s to landing without any aerobrakeing passes. Just nosed into prograde and threw open the airbrakes. Easiest deorbit of my life.

Is this exploiting bugged aero physics or is this working by design?

[fourfa]

ssssshhhhhhh

[theend3r]

1 hour ago, Sresk said:

...exploiting bugged aero physics...

Get FAR if you don't want easily exploitable physics.

[Sresk]

10 hours ago, theend3r said:

Get FAR if you don't want easily exploitable physics.

I can't I'm not sure what mods it doesnt like but when i turn on FAR it turns all of my cargo bays into KRaken drives.

[Superfluous J]

13 hours ago, theend3r said:

Get FAR if you don't want easily exploitable physics.

 

2 hours ago, Sresk said:

I can't I'm not sure what mods it doesnt like but when i turn on FAR it turns all of my cargo bays into KRaken drives.

That sounds like a physics glitch you could really exploit.

[Red Iron Crown]

14 hours ago, Sresk said:

Is this exploiting bugged aero physics or is this working by design?

Exploit, to my mind. A dinky little antenna shouldn't shield the entire craft from the bulk of reentry heat.

13 hours ago, theend3r said:

Get FAR if you don't want easily exploitable physics.

This effect occurs in FAR, too.

[Martian Emigrant]

14 hours ago, Sresk said:

So the other day I read a tip about putting the smallest antennas on the nose of your space planes to help with heating problems on re-entry.

The other comments seemed to take it in stride as a kerbaled aerospike (not to be confused with the rocket) see here https://en.m.wikipedia.org/wiki/Drag-reducing_aerospike.

So I tried it out and holy$*!@. I pushed an SSTO to over about 1400m/s at 20k and blew up due to heating. Put spikes on the nose and the 4 ram intakes and pushed that same exact plane to over 1700 m/s at 20k feet before jumping off to space.

I then returned that plane from minmus by setting my peri at 15k and went screaming in from orbit at over 3300 m/s to landing without any aerobrakeing passes. Just nosed into prograde and threw open the airbrakes. Easiest deorbit of my life.

Is this exploiting bugged aero physics or is this working by design?

I saw that...somewhere and been using an antenna on the nose of my MK1 SSTo and they don't explode anymore on the climb. I was unaware you could deorbit nose first. That's good to know.

You must have seen torn-off flight controls after a RUD. They move funny as if 100% of their weight was on the hinges. I think it's kind of the same with the antenna. The root is the real part. it's protected by the shaft and doesn't get as hot.

 

ME

[Martian Emigrant]

Just played a bit in 1.2 and the Smaller Communotron the 16? Is now destroyed by air pressure when extended.

So they "Fixed" it.

 

ME

[Sresk]

1 hour ago, Martian Emigrant said:

Just played a bit in 1.2 and the Smaller Communotron the 16? Is now destroyed by air pressure when extended.

So they "Fixed" it.

 

ME

It's torn off in 1.1.3 I'd you extend it too. Try it again but leace them retracted. Try it with and without. As long as I leave them retracted and stay nose into the wind I can go about 1000 m/s faster with them than without them. 

I can't tell if they also reduce drag or just reduce heating effects.

And at @Martian Emigrant I've been deorbiting nose first without my nose spikes for a while. Lots of airbrakes on the back and keep you decent real shallow by keeping your nose up... about 10-20 degrees above prograde if your plane is stable at that aoa. But you can't dip below about 40k until you've shed a lot of speed.

With the nose spikes you can drop straight down to 20k and just dump all your speed... I've been having trouble undershooting my landings now.

[Jonfliesgoats]

It's a bug.  Controlling shock waves is a really important part of high speed aerodynamics and a small protrusion ahead of the nose of a plane does start a shock a little earlier and easier.  This will reduce some of the heating you'd see on, say the nose of your craft, due to compressibility.  IRL you don't see this much on hypersonic craft because you are always encountering your air at some condition slightly different than what is designed (control petrubations, turbulence from interfering objects, even bug and debris impacts).  Unless you can adjust the geometry of your spike ahead of the plane, it loses its efficacy and actually starts creating a whole host of new problems.  Also, supersonic and hypersonic flight involves just a lot of force.  Combine heating with high dynamic pressures and the vibrations on even a robust spike create shock assymetric forces that become a problem.   

Antennae ahead of intakes would be a pretty bad thing in real life due to what they'd do the the airflow in the intake and, eventually, the compressor face of the turbine.  If you're an aerospace nerd (you are playing KSP!) you'll have noticed that really fast, air breathing planes have sharp edges on the inlets to their engines.  This is all about having a controlled and series of shocks at speed to present acceptable air to your engine.  This is also why there's a variable position spike on the leading edge of the SR-71's air intakes.  When you make those sharp edges dirty with rods, tubes, dents, dings, etc, you get an unhappy engine.  Unhappy engines tend to belch fire out the front, fail and generally cost a lot of money in molten parts.

Holy crap!  I'm typing a lot.  I'm gonna end my nerd-pontification here and allow others to reveal my stupidity.

[fourfa]

The magic antenna on the front of the Mk2 cockpit definitely works, but I've never had a shock cone overheat in any conditions, antenna or no.  No need to buff the intakes in my experience.

[theend3r]

10 hours ago, Red Iron Crown said:

This effect occurs in FAR, too.

Really? Aero stress doesn't break it?

[KerikBalm]

On 9/29/2016 at 6:49 AM, Sresk said:

So I tried it out and holy$*!@. I pushed an SSTO to over about 1400m/s at 20k and blew up due to heating. Put spikes on the nose and the 4 ram intakes and pushed that same exact plane to over 1700 m/s at 20k feet before jumping off to space.

You must have been using some sort of mod, because the airbreathing engines won't push a craft that fast/past mach 5...

Unless you went closed cycle, and I'd just wonder why you'd go into closed cycle mode that low anyway...

[Van Disaster]

1 hour ago, theend3r said:

Really? Aero stress doesn't break it?

No, it's just not spectacularily useful though - I don't know if it was something else modifying it but it's max temp wasn't much higher than the Mk1 cockpit last time I tried. Mk1 re-entry is really easy though, just have to be patient. If you're overheating on the way up then either your craft needs more wing area or your profile is horrible.

Spoiler

You don't *want* a sharp nose hypersonic, it will melt. There's a good reason for most hypersonic craft being blunt bodies. The antenna works by just being the nose piece on the craft, there's nothing technical like shock waves involved.

Edited September 30, 2016 by Van Disaster

[theend3r]

5 hours ago, Van Disaster said:

No, it's just not spectacularily useful though - I don't know if it was something else modifying it but it's max temp wasn't much higher than the Mk1 cockpit last time I tried. Mk1 re-entry is really easy though, just have to be patient. If you're overheating on the way up then either your craft needs more wing area or your profile is horrible.

  Hide contents

You don't *want* a sharp nose hypersonic, it will melt. There's a good reason for most hypersonic craft being blunt bodies. The antenna works by just being the nose piece on the craft, there's nothing technical like shock waves involved.

I don't know. Sure, it works like that in reality but in KSP I had the most success (100% safe reentry rate with even otherwise not reentry ready planes) with making the plane spin a like crazy so the heat doesn't build up. A very kerbal solution.

[Sresk]

11 hours ago, KerikBalm said:

You must have been using some sort of mod, because the airbreathing engines won't push a craft that fast/past mach 5...

Unless you went closed cycle, and I'd just wonder why you'd go into closed cycle mode that low anyway...

Yeah OPT has got an air breathing jet that's weak at low speeds but has an insane high speed thrust. I'm sure it's over powered but its fun.

[Van Disaster]

9 hours ago, theend3r said:

I don't know. Sure, it works like that in reality but in KSP I had the most success (100% safe reentry rate with even otherwise not reentry ready planes) with making the plane spin a like crazy so the heat doesn't build up. A very kerbal solution.

I've noticed that ( and occasionally misused it for something that's being a real pain ) - you don't need to actually spin, you can just ... wiggle, I guess yaw a bit, pitch a bit, I guess it changes where heat is applied. I dunno, the heating system is still a bit of a mystery. Had one thing which rocked it's payload colliders out of the bay occasionally and *that* took all the heat momentarily ( luckily only momentarily given it's heat tolerance was something like cheese ).

[EpicSpaceTroll139]

15 hours ago, KerikBalm said:

You must have been using some sort of mod, because the airbreathing engines won't push a craft that fast/past mach 5...

Unless you went closed cycle, and I'd just wonder why you'd go into closed cycle mode that low anyway...

You don't need mods to reach 1700m/s with jet power. RAPIERs in air-breathing mode can do this. It's hard to design a plane with low enough drag and high enough temperature to do this, but it is possible. So far I haven't made one that can sustain it though.

Edited September 30, 2016 by EpicSpaceTroll139

[fourfa]

There must be a relevant challenge thread, surely

[Van Disaster]

19 minutes ago, fourfa said:

There must be a relevant challenge thread, surely

Fairly recent.

 

[Palaceviking]

Ksp doesn't have an airspike system yet, real life does.......this is the kerbal airspike,  I'm using it

Edited October 1, 2016 by Palaceviking

[Sresk]

19 hours ago, EpicSpaceTroll139 said:

You don't need mods to reach 1700m/s with jet power. RAPIERs in air-breathing mode can do this. It's hard to design a plane with low enough drag and high enough temperature to do this, but it is possible. So far I haven't made one that can sustain it though.

Put spikes on the front of your plane and suddenly you can sustain it. I was playing around with this the other night and got into a stable glide at about 25k and put my nose 3 degrees above the horizon. I was able to push my apoapsis  above 150k with my peri at 25k before I switched over to closed cycle. Not sure could have done it with stock engines... but I know I couldn't have done it without the nose spikes.

19 hours ago, EpicSpaceTroll139 said:

You don't need mods to reach 1700m/s with jet power. RAPIERs in air-breathing mode can do this. It's hard to design a plane with low enough drag and high enough temperature to do this, but it is possible. So far I haven't made one that can sustain it though.

Put spikes on the front of your plane and suddenly you can sustain it. I was playing around with this the other night and got into a stable glide at about 25k and put my nose 3 degrees above the horizon. I was able to push my apoapsis  above 150k with my peri at 25k before I switched over to closed cycle. Not sure could have done it with stock engines... but I know I couldn't have done it without the nose spikes.

And yeah the high-speed challenges confirms how broken the combo of air spike plus OPT mod is I was over 2300m/s.

[EpicSpaceTroll139]

1 hour ago, Sresk said:

Put spikes on the front of your plane and suddenly you can sustain it. 

Actually I wasn't having problems with the heat blowing me up. My plane just didn't want to keep going that fast for whatever reason... I'll investigate it. I think it might have something to do with the heat making the engines produce less thrust or something...

[Sharpy]

I have a question: will such an antenna protect a shock cone intake?

I've got some cool engines with the MK3 and MK4 expansions, that can reach good 1400-1600m/s in the atmosphere - but the tip part of the SSTO always gets busted, be it standard nose cone, an intake, a hypersonic nose cone, a cockpit... it seems only the cupola can survive (!?).

Most preferably, I'd use a big shock cone intake. Can I protect it with the antenna?

[Red Iron Crown]

17 minutes ago, Sharpy said:

I have a question: will such an antenna protect a shock cone intake?

I've got some cool engines with the MK3 and MK4 expansions, that can reach good 1400-1600m/s in the atmosphere - but the tip part of the SSTO always gets busted, be it standard nose cone, an intake, a hypersonic nose cone, a cockpit... it seems only the cupola can survive (!?).

Most preferably, I'd use a big shock cone intake. Can I protect it with the antenna?

Yes, it should work. You'll have to place it and offset it into position.

You might also try a small, empty fairing for your nosecone, they have great heat tolerance and offer some space to hide utility parts. Another option is to offset the nose gear to be the most forward part if the design permits it, they also have great tolerance.