Battle of the jets

[AeroGav]

This is a Space game, so the number one consideration is performance fast n' high.

In that sense,  the pecking order is -

1. RAPIER  

pros - just awesome

cons - weak subsonic thrust, but shouldn't be a problem for aerodynamically clean spaceplanes.  For other types of aircraft this is a disadvantage.

 

2. WHIPLASH

pros - very good performer.  makes excellent sub-orbital, zoom climbing air launchers

cons - no reason to use once the RAPIER appears.  Comes rather late in tech tree.

 

3.  PANTHER

pros - not that far behind the whiplash and appears relatively early.

 

4. JUNO

pros - You can actually make a barely orbital spaceplane with these.  Hang about 10 off your wing, should get to 12km at 1.3mach,  then fire up a fuselage mounted Terrier.  At 17km they flame out, use a decoupler to blow off the cluster of jets. You'll probably want your undercarriage on separators too, as you'll be on fixed gear at this point.  Considering how early they appear, this is good going.

 

BTW all the people who say the Panther is thirsty are dead wrong.    Yes, it guzzles fuel in Wet mode at low altitude.    Take it up to 20km in Wet and it sips away.  Circumnavigate the globe on less than 800 fuel.

[KerikBalm]

2 hours ago, ment18 said:

I've done a little testing and found that the Panther vastly out performs the wheesly.  It spools up faster, has afterburner (which is instant) and has gimbal. 

Even without afterburner, it can get your plane going significantly faster...

It is a bit weak without afterburner.

The engine is actually lighter than the Wheesely, and in dry mode, its static TWR is lower... With plane designs I often care about Thrust To Node Ratio(TNR) more than TWR. The panther's dry mode TNR is rather poor. I don't find its dry mode very useful.. but in theory it could let you cruise at mach 1.8 where it gets the most thrust (I hope... I don't know if its possible to get a low enough drag design to cruise at nearly mach 2 with the dry panther).

I pretty much only use it in afterburning mode... which at 4000 ISP makes it compet with the turboramjet... which basically means I'll only pick it over the turboramjet when I need low speed, low altitude(ie, high-ish atmospheric pressure) TWR - Laythe sea level's atmospheric pressure is still high enough that the wet panther (uh oh, just had a dirty thought about a wet... "cat"... maybe this engine's name and the name of the mode should be reconsidered before other people make those jokes) performs better than the turboramjet - at 0.6, even 0.4 atms, the panther-wet has a better (% of max thrust):(atmospheric pressure as a % of kerbin sea level) ratio than the truboramjet's ratio... which means the panther has a better static thrust than the turboramjet (at 1 atm, they have the same static thrust... and at 0.2 atms, the turboramjet has much better static thrust... but in between there, the wet panther wins)... and its lower mass.

I only have a use for panthers as VTOL engines... basically*. The dry mode is nice to conserve fuel when flying to a landing site or a point that I want to start the ascent to orbit... if its even enough to sustain horizontal flight... but mostly it won't save that much fuel

* My VTOLs are typically tail sitters, no seperate thrust and lift engines... and they go to orbit, which means rapiers... the wet panthers are just there to help the rapiers lift the spaceplane up vertically and transition to horizontal flight.... I have doubts that with the rapiers shut off and the panthers in dry mode that there would be enough thrust to keep them flying... at least if they are fully fueled. - They are laythe ISRU craft... fly over ore, pull up, pop chutes, land, mine+ repack chutes, vertical launch and fly to equator(if the fuel depot is in an equatorial orbit, otherwise, just fly to a point under the fuel depot's orbit), insert into orbit.

 

[WillThe84th]

8 hours ago, KerikBalm said:

Not in afterburning mode.

They both get 4000 Isp if you are actually using them for high speed travel

If you aren't talking afterburning mode... then they aren't even comparable... and its efficiency is very good and close to the wheesely, and much much much better than the juno/whiplash/rapier

Yeah, bad reasoning on my part. For some reason I thought the Isp in afterburning mode was something like 7000. Now for better reasoning: I like the panther because it has a high gimbal range, which can be utilized to do insane stunts, like going backwards. I also like how you can build fighter jets with them. Like this one:

 

But actually, if I was making a science plane, I'd use the goliath.

[AeroGav]

3 hours ago, WillThe84th said:

But actually, if I was making a science plane, I'd use the goliath.

I'm in a "no rockets" career challenge and honestly I see no reason not to use the Panther, once you've got it.     At 20 km it uses only a tiny amount more fuel than a Wheezey,  but you'll be doing Mach 2.5 instead of Mach 0.9.  A lot of the contracts you get require observation of specific co-ordinates at altitudes exceeding 19,400M.   With a Panther that's your cruising altitude,  on a Juno, Weezer or Goliath you need to bring a liquid fuel rocket to turn on for a pop-up climb to fulfill these missions - pain in the rear.

 

Panther only guzzles if you run it wide open at low altitudes.  

Edited December 8, 2015 by AeroGav

[RocketBlam]

I don't get the Panther. The thrust starts to drop immediately, even before you've taken off, and just keeps going down. I don't understand it. Adding speed and/or altitude seems to do nothing, wet or dry, except cause thrust to decrease.

ETA: OK, actually the thrust will slowly increase with speed, but decrease with altitude.

EATA: OK, I think I've got it. It wants to be going as fast as possible at all times. You want to build up speed before you pitch up very much. It seems even more prone to this than the RAPIER.

Edited December 14, 2015 by RocketBlam

[The Optimist]

Rapier Rapier Rapier Rapier Rapier Rapier

[Temstar]

Seeing Rapier being so dominant as "best jet engine" even for aircrafts not intended to go into orbit feels wrong. Perhaps what's needed is an air-breathing only mode version of the Rapier. Call it the S.T.I.L.E.T.T.O engine or something.

[MKI]

Rapier if going to space.

Wiplash if going to space and not using Rapier for what ever reason

 

Otherwise what-ever looks good. 

 

 

[KerikBalm]

On 12/15/2015 at 4:00 AM, Temstar said:

Seeing Rapier being so dominant as "best jet engine" even for aircrafts not intended to go into orbit feels wrong. Perhaps what's needed is an air-breathing only mode version of the Rapier. Call it the S.T.I.L.E.T.T.O engine or something.

How would that be different from the Turboramjet? Its airbreathing only, and close in performance to the rapier, it just doesn't get you as close to orbit.

I don't read this thread and conclude that the rapier is best even if you're not going to orbit. I read this thread and conclude that most people care about getting to orbit the most.

The rapier is a terrible VTOL engine. Its got terrible static thrust. Its got the worst ISP by far of any of the airbreathing jet engines. It is the heaviest airbreathing engine. It is the only jet engine which lacks an alternator for producing electric charge. Generally, if you aren't going to orbit, you should not be using the engine.

On 12/15/2015 at 7:28 AM, MKI said:

Rapier if going to space.

Wiplash if going to space and not using Rapier for what ever reason

I would slightly modify that to "orbit" rather than "space"

The whiplash is great for getting to space. Its static thrust is a lot higher than the rapier, and it can break mach 1 in a steeper climb than the rapier. Its not too hard to get an apoapsis above 70km with the turboramjet by climbing steeper than you would climb with the rapier.

I think the turboramjet if better than the rapier for flying around kerbin/laythe without going to orbit. If you're never concerned with going more than halfway around a given world, suborbital trajectories with the turboramjet are what you want, not going all the way to orbit, and then deorbiting again.

4000 vs 3200 Isp is not insignificant ... its 25% better. Thats more than the difference between the radial 24-77s and the poodle.

 

*edit* So I was too negative about the panther engine in dry mode earlier.... its actually enough to get going quite fast if you design your craft right... >650 m/s at 9,000 Isp... not bad at all.

 

Edited December 21, 2015 by KerikBalm