Anyway to keybind CR7 RAPIER toggle?

[AndreyBR123]

Anyway? I made an plane that is heavy and need the closedcycle mode to take off, but I need to click right mouse button on all the engines one by one to change from closedcycle to airbreathing mode.
Anyway to make an keybinding to make this easier?

[ForScience6686]

Action groups.  You have three tabs in building mode, construction, action groups, and crew.  Even if you don't have custom groups available you can re purpose one of the main groups.

[AeroGav]

2 hours ago, AndreyBR123 said:

Anyway? I made an plane that is heavy and need the closedcycle mode to take off, but I need to click right mouse button on all the engines one by one to change from closedcycle to airbreathing mode.
Anyway to make an keybinding to make this easier?

EEW,  how much Oxidizer does that burn up out of interest?  These days I don't use any Oxidizer at all, just run off a combo of Panthers (that i jettison after mach 2.7),  Rapiers and then NERVs.

There's a bit of a cost in chucking away engines of course, but the lower tier jets aren't that spendy and outperform Rapier and Whiplash at lower speeds.  How much better would your delta V be if you just hung some engines (or even solid rockets?)  off the wing that you ditch when airborne.

You can see that I just hang my Panthers off the back of NERV, since the Panthers will be used below 20km and the NERV above 20km - they'll not both need to be active at the same time.    

Also btw,  I have a lot of wing area.   I normally only use the afterburner as i'm crossing the sound barrier and above 15km,  but if I do start with full AB,  we don't need much runway...

 

 

Landing performance is pretty good as well

 

Ironically, the large wing explains why i need Panther "boosters".   Rapiers produce very low power below Mach 1.    I get too much drag if I try to break the sound barrier below 10km.    The upside is that we can land anywhere,   and it's extremely efficient above 25km.  

[ForScience6686]

I would adjust your flight profile or visit the drawing board instead of dumping engines.  That's counter productive to using an Ssto.  Use low aoa and build speed till over the hump then climb.

[AeroGav]

19 minutes ago, ForScience6686 said:

I would adjust your flight profile or visit the drawing board instead of dumping engines.  That's counter productive to using an Ssto.  Use low aoa and build speed till over the hump then climb.

The criticism would be valid if it only just made it to orbit but this thing can fly to Minmus with an ISRU loadout unrefuelled,  empty it can land on Minmus with 900dv left,  and it can put a 7 ton payload in an elliptical orbit with a periapse at Mun's altitude - not bad for a 42 ton t/o weight.  For the price of two Panther engines.   That is much, much cheaper than a rocket of the same capability.

1 - use low aoa and build speed - i use low aoa through the whole flight. But trying to go above mach 1 makes too much drag below 10km, even in a shallow dive.

2 - go back to the drawing board - yes if i reduced the wing area by 75% it would go supersonic at sea level and you could fly the way you describe.  But then it would only be able to fly above 20km by running a  high nose angle and would have too much drag to accelerate on the power of 2 nerv only. So then you start fitting lots of oxidizer tanks and get less delta v in orbit.     Also wouldn't fancy landing that on Duna with small wings..

[ForScience6686]

Valid points for sure.  Sorry I mixed up posts and thought he was speaking of an Ssto, but that is not mentioned.

[AeroGav]

I'd be interested to see Andrey's design.  Certainly if you're pushing the performance envelope some part shedding is acceptable.   If not and he's new to the game, he still deserves to see his creation fly.   After that look at design improvements.

I wonder if he's actually building an SSTO rocket, that would make a lot more sense.    Even then,  a cluster of Flea SRBs that give 4g acceleration for 8 seconds is a good way to get up to 240 m/s.     Closed cycle has an ISP 10 times worse than Air Breathing, seems crazy to do that in the atmosphere.

Looking at the numbers -

Rapier Airbreathing 105 static kn 

Closed Cycle  162 Atmospheric kn 

so, for an extra 60kn thrust you'll burn an FL-T100 worth of fuel (0.5T , Cost 150) after 9 seconds

Strap on a Flea,  you get an extra 160kn thrust from the Flea over and above what the Rapier is doing in Airbreathing, for 1.5T mass and cost of 200.  A Flea burns about 9 seconds.

The Panther costs 200 and makes 85 Static thrust in Dry mode (giving a whopping 9000 ISP) vs 130 in AB, for a mass penalty of 1.2T.

So,  drop tanks, solid boosters or drop engines?  fun tradeoff

Edited April 16, 2016 by AeroGav