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wafflemoder

Using Intake Air as a RSC alternative

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It would be great if there was an alternative RCS thruster that used intake air instead of mono propellant. This would allow for free RCS while in atmosphere on Kerbin or laythe.

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But if you need to use RCS while in the atmosphere, then something is wrong with your vehicle.

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When I read this, I thought you meant that it would get stored in a tank then used as a propellant in space. IE, like the RCS for Kerbals

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It would be great if there was an alternative RCS thruster that used intake air instead of mono propellant. This would allow for free RCS while in atmosphere on Kerbin or laythe.

Intake air is just an oxidiser; it'd need fuel to react with in order to generate thrust in an RCS system, so you'd just be reinventing the gimballing turbojet. If you want to use ambient air on its own for attitude control, I think aerodynamic control surfaces would serve the role much better.

-- Steve

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When you hover,the aerodynamic control surface don't work.

Also,you can compress the air intake and shoot the compressed gas like an RCS do.

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I think what wafflemoder is suggesting is a system to take oxygen from the atmosphere and store it in a compressed form, then use jets of compressed air for RCS instead of monopropellant.

I'll admit it's an interesting concept, but I don't really know how practical it would be compared to just taking a full tank of monopropellant with you in the first place.

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because fuel of monopropellant isn't unlimited while compressing air from air intake is unlimited(as long as you are in the atmosphere)

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I'm sorry, but why would you even need to use an RCS system when you're in the atmosphere in the first place?

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I'm sorry, but why would you even need to use an RCS system when you're in the atmosphere in the first place?

Ever tried to balance a VTOL? Air nozzles can be very useful in this case. And that's exactly why a Harrier Jumpjet has air nozzles just like this. I guess this is pretty much the reason why Bac9 added them to the B9 Aerospace mod.

As long as you have a running jet engine those air nozzles have an unlimited supply of propellant. They function in the same way as RCS nozzles but do not share a common resource.

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Okay, didn't think of this as a "cold gas" jet. So I guess it'd use electricity to compress ambient air (not necessarily IntakeAir but any atmosphere) into a low-power RCS mount. I know I've been rooting for an electrically-powered ducted fan engine to propel aerial survey drones for worlds like Eve and Duna (and Jool's outer atmosphere, perhaps) which isn't terribly different. A smaller version you could mount radially for attitude control might not be a bad idea.

-- Steve

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B9 already has this and it really isn't more than a config edit away. the B9 system is reasonable, balanced, and really should go ingame. I do also agree that there should be electrically and fuel driven propeller systems for extraplanetary atmospheric flight.

Anton, can I use that idea for a mod part?

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....all this time I thought that monoprpellent was just a compressed gas... I was wrong as I see, because if that was the case, the idea of recharge the RCS tanks while an intake is active won't be so silly... in fact, would be very logical.

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Ever tried to balance a VTOL? Air nozzles can be very useful in this case. And that's exactly why a Harrier Jumpjet has air nozzles just like this. I guess this is pretty much the reason why Bac9 added them to the B9 Aerospace mod.

As long as you have a running jet engine those air nozzles have an unlimited supply of propellant. They function in the same way as RCS nozzles but do not share a common resource.

Fair enough. That would be incredibly useful for such a craft, I'll admit. Must not have been thinking clearly earlier.

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i did bleed thrusters in my mod that took bleed gas from the main engine and fed it into rcs trhusters. this is similar to what is used on the harrier jump jet for its hovering thrusters.

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Yeap, I did a Harrier analog using "compressedair" for main propulsion as well as reaction control - I used some resized small rockets using compressedair as a propellant and damned robotics rotating things to, well, rotate, using a turbojet with minimal thrust as a generator. You can do it just by abusing the stock electrical generator module every jet has.

Ducted exhaust has a few more uses than just reaction control, none that you can't also do by moving propulsion to the nozzles though.

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I'm sorry, but why would you even need to use an RCS system when you're in the atmosphere in the first place?

well sometimes i use RCS for Planes that are Very back or Nose heavy So thats my reason

i Can easily implement something like this Using my modding skills

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Compressed air thrusters are great for planetary maneuvering, being able to turn my airships on a dime without carrying tons of rcs fuel is key, you can make fast land probes. And launch assisting for my flying planetary probes (sometimes you need that little extra oomph to get airborne)

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i could Implement this very Simply By Making another Resource called Compressedair then make a RCS Block Use compressedair

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i could Implement this very Simply By Making another Resource called Compressedair then make a RCS Block Use compressedair

Why would you? It's already in the B9 Aerospace mod!

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On 8/31/2013 at 11:46 AM, Sir_Tramalot said:

But if you need to use RCS while in the atmosphere, then something is wrong with your vehicle.

i think he wants atmosphere RCS for if he makes VTOLs or Helicopters... Mainly VTOLs

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One of the earliest German (WWII or slightly before) helicopter designs used compressed air jets to drive the rotor so it didn't produce reaction torque, and hence could fly without a tail rotor.  The air was pressurized by an aircraft radial engine driving a big centrifugal pump.  As noted, the Harrier uses reaction controls powered by air bled from the engine compressor; there was also a research variant of the F-104 Starfighter that had a cold gas (i.e compressed nitrogen, in that case) RCS system for use with a rocket motor that could kick the jet to well over 30 km altitude, where the jet engine and aero control surfaces were effectively dead weight.

The Isp for RCS propellant is consistent with catalyzed hydrazine -- but I guess we'd have to have Real Fuels to be able to use hydrazine as fuel with an oxidizer like nitric acid, or use high test peroxide as monopropellant and also as an oxidizer.  But then we'd have to allow for boil-off of liquid oxygen on interplanetary transfers, and liquid hydrogen for nukes even on a Minmus trip.

Easier to just let liquid fuel be liquid fuel, and feed jets, nukes, and mix with generic oxidizer to work in bipropellant engines.

 

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The thrust measuring rig and later the harrier used a reaction control system powered by the jet engine.

Figs_16_Final_reaction_control_system.jp

Think KSP should have one too but with new parts. more parts! MORE PARTS!

 

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