ORIGINAL: siclick33
why haven't mfgr's picked up on and started exploiting the "thrust augmenting" tail pipes?
What is the theory (in layman's terms) behind the thrust augmenting tailpipe? Is is simply a divergent duct increasing the exhaust pressure? if so, there is always a penalty to be paid and surely this would be in terms of exhaust gas velocity (and hence top speed).
I am still a believer that you don't get something for nothing.
Also, the thrust that is being measured by most people is static thrust. Does anyone know the magnitude of the benefit these "augmenting" pipes actually have in the air?
I had test both design of the pipe in the same model.
This while back with the Ram 500 in BVM ultra viper.
The taper pipe had much higher efflux velocity and the speed is much faster than the pipe with more static thrust.
I had test the taper pipe at 12 lbs of thrust only lost 1/4 lbs. That is the bellmount pipe set up. The bypass set up loose up to 2 lbs. The reason is the bypass not allow cool air to draw in the pipe. That why recommending put some hole in the back of bypass to help get cool air in to improve thrust lost.
In the last 2 years I been doing a lot R&D with high performance E-power fan system.
Everyone is after high static thrust for marketing interested point of sale.
I going for high efflux velocity design.
Sure enough. My tiny little fan had 30% less static thrust can out fly any bigger fan that had more static thrust with low efflux velocity.
There is no secret to pipe design.
If you want more static thrust. You will had less efflux velocity.
If you want more efflux velocity. You loose little bid on static thrust.
You can't had both.