I once read a brief explanation (in a sport bike magazine) of radiators in F1/racing cars that were "zero drag" in nature.
The theory/practise as I understand it was that the drag created by the lower pressure, cold air going through the radiator was offset by hot, higher pressure air exiting it, acting as a kind of propulsion effect.
It sounds very simple and practical. Does it really work and is it being used?
It could be very true. I worked on F-18s and they had HUGE radiators, or heat exchangers as they are called on the aircraft. They weighed about forty pounds, about 3 feet long by 8 inches wide by 6 inches deep. They were also very very heavy. They had a very tiny hole, about the size of a playing card, for inlet of fresh air through a duct in front of it. The ducting on the backside was very large in comparison as well. It was more than enough for cooling while in the air. They go fast enough to not need any help. What they used on the ground for cooling air through that little inlet were things called ejector valves. They worked by bypassing bleed air off the engines, that would normally go through the heat exchangers and be cooled for use in the aircraft to cool fuel, computers, and other things like the cockpit, and dumping it behind the heat exchangers. This hot air rushing through behind the heat exchangers would draw air from in front by way of the low pressure area. They also would scavenge water from the air further down the system by way of an extractor and spray it over the heat exchanger to aid in the cooling of the air even further. It works so well without even the use of freon or other refrigerant, it would actually make ice chunks in the cooled air! Simple science in that system would cool down 1800 degree air in a matter of seconds to ice cold! Pretty amazing stuff. So I would guess the principle is either the same, or really close to it.
The radiator is not "zero drag", however, the radiator + duct can be (and can even develop thrust).
When heat is added to the airstream, pressure increases - with careful nozzle design, this pressure can be used as a jet.
I suppose the best anology would be a ramjet, only instead of combusting fuel with the air to raise temperature (and thus pressure), heat exchanges raises the temperature (and pressure).
Murphy's 9th Law of Technology:
Tell a man there are 300 million stars in the universe and he'll believe you. Tell him a bench has wet paint on it and he'll have to touch to be sure.
I can't remember where on the web, but I found a place to buy a pulse jet kind. Talk about an evil sound Pretty cheap too. I'll have to go find it now.
wow how does this pulsejet engines work.
Seems like they are very easy constructed so that you can build them
in every hobby workshop.
Can somebody explan the priniple?
Are there any videos available?
Yes but is it being used in F1 today and at what capacity?
You would think that road cars could use this more effectively rather than just allowing the expelled air (from the radiator) to just dissipate around the engine and leave under the car somewhere.
Would the Lotus Elise with its hood (bonnet) hot air exit be an example of this low drag cooling system?
I always wondered the same thing G-rock. On my truck there is a big fan shroud for the radiator, but once the air goes through it, it doesn't really go anywhere. Not anywhere I can immediately tell anyway. It may do the exact opposite and get 'sucked' out of the engine compartment by the fast moving air beneath it. So I would say IMO that F1 cars are definitely using something like this. It makes too much sense not to.
I want one now! I could do some serious damage with one of them things.
Oh just out of my price range. Me and a mate are saving up to have a 2/3 jet go kart. If we get the money it will be a death trap(no safety whats the point at a planned 300mph plus ) if we do get round to building it I'll take pics and post them
G-Rock wrote:I once read a brief explanation (in a sport bike magazine) of radiators in F1/racing cars that were "zero drag" in nature.
The theory/practise as I understand it was that the drag created by the lower pressure, cold air going through the radiator was offset by hot, higher pressure air exiting it, acting as a kind of propulsion effect.
It sounds very simple and practical. Does it really work and is it being used?
Is it somehow related to this idea of mine from year and a half ago?
Pretty cheap too. I'll have to go find it now.
) if we do get round to building it I'll take pics and post them
