You don't have to send fuel. The exhaust would be enough, after all F1 engines throw liters and liters of unburnt fuel through the exhaust just for the purpose of cooling the engine. In that sense, it's some kind of KERS.
Actually, there are some prototypes on the pipeline that use the exhaust heat: at least one of them (proposed by BMW and perhaps ad portas of going to market) uses steam. We talked about it years ago, when KERS were a novelty.
At that moment, FIA said (if I remember well) that the KERS idea was about recycling energy and that they intended to start by reusing brake energy (those are the KERS we have today) and then they would allow exhaust energy recovery.
This proposal would use unburnt fuel in the exhaust, so I find it very ecological, KERS-ian, Antiglobalwarm-ian and certainly made for FIAland and PressReleaseLand.
I think Green Peace would be proud and little baby dolphins would squeak in joy if some day they hear about it in their little gray iPods.
Anyway, this is just to say that we already made the calculations one day I misunderstood another related question, here:
viewtopic.php?f=4&t=9526&p=226755
... so, you could use them, calculations, to fit the thing into your design. I assume this time I understood the question correctly (improbable).
If I did, the I can say it won't be easy to fit it, lemme tell you.
I estimated that you need a 30 cm diameter exhaust pipe and a 60 cm diameter combustion chamber plus a high efficiency valve
and 2.8 m of tube to get 200 kg of impulse force. The longer the tube, the higher the impulse.
For 100 kilos you need like 2.1 meters. A design with this shorter tube and half the thrust has smaller combustion chamber and exhaust pipe diameters, of course.
I mentioned that locating a valve in the exhaust is not what you would call ideal for an Otto engine, but, who knows, perhaps tuning it correctly it could actually help the engine cycle.
Surely it would be a booster if you use a valveless engine. Which is actually a tube with fuel you burn...
So, I think: what's refraining the teams from burning that unburnt fuel already? You just need an ignition source and presto. Actually, it makes a lot of sense in the EBD era (already gone): after all you have a lot of "potential gases" residing in that unburnt fuel.
I guessed in my previous post that maybe the material you would need to isolate the additional heat created by that fuel could be a disadvantage.
If the pipe is very short and relatively thin, like F1 exhaust pipes are, then the impulse is very low. Like 10 kilos for a 2 feet or so of pipe at 15 cm of diameter, which I think is a realistic design that can be fitted under the engine hood. Now, probably the heat shield you would need could weigh more than the impulse you get.
I know of no regulations that forbid such an arrangement, except the one that says that your car can only have one engine, but I'm not sure if the regulations mention something like "any other engine
connected to the power axle except the KERS" or similar. If that's the case (I feel lazy today to check) then it would be feasible, as a pulsejet is not connected to the power axle.
It makes a lot of noise, which could be a plus, except in the circuits that already have a lot of problems because the neighbors complain, which are... most of them.
The idea would be to race at Elkhart Lake, for example (it's an airport, in case you don't get the smarty pants joke).
Just in case, here you have a pulse jet kart. Nice exhaust, btw...
[youtube]
http://www.youtube.com/watch?v=5U-grFuXZ9U[/youtube]
... and here there is a trike with TWO pulsejets. I'd guess you are thinking on one pulsejet for each bank of cylinders, so...
[youtube]
http://www.youtube.com/watch?v=6Hxgfohmz8k[/youtube]
