Kwik
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| posted on 28/5/10 at 12:50 PM |
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non-locost mega boost!
before my physics AS exam yesterday, i had a thought.
i was thinking how turbos and superchargers worked (from my understanding the force air into the engine?)
well i thought of ways to improve upon this, and i thought, jet engine.
not a full size boeing 747 engine, but a model plane engine:
http://www.quicktechhobby.com/Engines/QTH%20JET%20ENGINES.htm
as you can see theyre expensive bits of kit, but if you had one running on the body of a car, and was used like a turbo to force air into the engine
(with an increased fuel mix) would it act like a super powerfull super charger? this is with the engine running off its own system and own fuel, the
air comming out the back can hit 120mph easily.
or will it just blow an engine up? could it be an alternative to NOS? as it has to be refilled with jet engine fuel?
thoughts?
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cd.thomson
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| posted on 28/5/10 at 12:58 PM |
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its basically impossible.
the main goal when using a charger is not to get as much boost as physically possible. If that were the case you'd just fit an absolutely
massive turbo or a string of smaller ones. The limiting factor even at normal levels of boost is the engine. No normal engine could deal with a that
much air being fed into it.
youd have to control the boost somehow as super/turbocharger boost is directly linked to what the engine is doing at the time.
Not to mention intake temps, time to spin the jet engine up, total inefficiency of running an engine to boost another engine etcetcetc
etc
etc
Craig
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BenB
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| posted on 28/5/10 at 12:59 PM |
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It's a nice idea but it wouldn't work!!! And as said you'ld normally only want big boost at high RPM. A turbine would give megaboost
all the time....
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CNHSS1
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| posted on 28/5/10 at 01:03 PM |
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similar idea has been done using the gas turbine from a helicopter starter
http://www.youtube.com/watch?v=11687nVdzdk
http://raceenginedesign.biz/Manic-Beattie.htm
its currently the fastest accelerating car on UK hillclimbs, inc faster than all the F1 engined stuff (V10 Arrows, Cosworth V8s etc).
Nic Mann, the cars creator, built, ran and dominated hillclimb and drag events in his twin turbo + nitrous Moggy Minor V8 in the 80s....
http://www.youtube.com/watch?v=VUu5eJPEigw
as for how it runs, basically has constant boost from idle thru to redline!
[Edited on 28/5/10 by CNHSS1]
"Racing is life, everything else, before or after, is just waiting"---Steve McQueen
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jimgiblett
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| posted on 28/5/10 at 01:40 PM |
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quote:
Originally posted by CNHSS1
Nic Mann, the cars creator, built, ran and dominated hillclimb and drag events in his twin turbo + nitrous Moggy Minor V8 in the 80s....
Wow Nick Mann.......... he was my Street Machine" and "Hot Rod" magazine hero of the 80's. I wondered where he went.
That Moggy was mental in such a good way!
- Jim
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CNHSS1
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 posted on 28/5/10 at 02:18 PM |
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he pops up at shelsley walsh and gurston down and prescott hillclimbs during the year.
the Moggy (and the Mannic) are a triumph of a lateral thinking by a gifted (if slightly potty!) engineer. Hes a proper boffin
"Racing is life, everything else, before or after, is just waiting"---Steve McQueen
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cadebytiger
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| posted on 28/5/10 at 02:32 PM |
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I would have thought that the air coming out of the back of those things it quite devoid of oxygen is it not?
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iank
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| posted on 28/5/10 at 02:34 PM |
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Wouldn't be much point using it directly into the engine as the goal of pushing more air in is actually to push more oxygen in and most of that
will have been burnt in the jet engine. You could use it to spin a turbo but then you might as well drive that using the car exhaust as you'd
need it on all the time (supercharged engines need to be low CR and different cam profiles to get the best out of them - which is why turbo cars are
not much fun when off boost).
Certainly worth thinking about though.
--
Never argue with an idiot. They drag you down to their level, then beat you with experience.
Anonymous
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CNHSS1
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| posted on 28/5/10 at 02:37 PM |
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quote:
Originally posted by cadebytiger
I would have thought that the air coming out of the back of those things it quite devoid of oxygen is it not?
the gas turbine is used to turn the turbo, rather than the engines exh gasses, basically turns the turbo into a gas turbine driven supercharger (as
opposed to crank driven of a normal supercharger).
The engine still pulls in air in the normal way to feed the cylinder head.
"Racing is life, everything else, before or after, is just waiting"---Steve McQueen
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cadebytiger
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| posted on 28/5/10 at 03:03 PM |
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quote:
Originally posted by CNHSS1
quote:
Originally posted by cadebytiger
I would have thought that the air coming out of the back of those things it quite devoid of oxygen is it not?
the gas turbine is used to turn the turbo, rather than the engines exh gasses, basically turns the turbo into a gas turbine driven supercharger (as
opposed to crank driven of a normal supercharger).
The engine still pulls in air in the normal way to feed the cylinder head.
Ahhh - that makes more sense! 
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RichieHall
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| posted on 28/5/10 at 04:11 PM |
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I think the biggest problem with this would be exposing the turbine in the turbo to the 690 degree exhaust from the gas turbine!
From the quick look I've had at Nic Mann's Manic Beattie he uses a Helo engine which would be a turbo-shaft not a turbojet, which takes a
mechanical feed from the final stage compressor to drive the turbo and not the exhaust gasses as you would from a RC turbojet.
If you could modify one of these RC engines with a drive shaft from the final stage and use this to drive the impeller that would work, however it
would be a major issue to gear it down far enough to give you enough torque to drive the impeller which giving you enough boost to be useful?
Rust is lighter than Carbon Fibre!
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