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Pulse jet driven tip turbine fan
Posted: Sun Jun 14, 2009 2:08 pm
by matt512s
Hi All:
I haven't written for some time, but I think I have come up with something. After reading
a patent on a suction tip turbine driven turbojet, it occured to me that such a device could
be driven by a pulsejet. The fan tip turbine scroll would be connected by ducts to a pulsejet
augmentor. The outside air flow thru the augmentor would come entirely thru the tip turbine
rather than by air passing by the pulsejet. The turbine would not be driven by the hot exhaust
and could be made from less exotic and expensive materials. Please tell me what you think.
Best Wishes;
Matt
Re: Pulse jet driven tip turbine fan
Posted: Sun Jun 14, 2009 3:12 pm
by Mike Everman
Hi Matt,
How about a link to that patent or a sketch? while I get the suction phase turbine idea generally, I can't make any sense of "suction tip turbine driven turbojet," and "The fan tip turbine scroll "
Mike
Re: Pulse jet driven tip turbine fan
Posted: Mon Jun 22, 2009 12:04 am
by matt512s
Hi; \
The patent is #4051671 and can be found on freepatentsonline.com. The suction driven tip turbine I refer to are turbine
blades mounted on the outer rim of the fan, rather than downstream of the combustor. Instead of using combustion gases
to drive the turbine (which in turn drives the fan), the air being drawn into the augmentor does the job. The scroll is an
annular duct that collects the air coming thru the tip turbine. For further tip turbine info, look up the LF 460 lift fan built by
General Electric. It used exhaust gas but the concept is similar. I hope this helps.
Best Wishes;
Matt
Re: Pulse jet driven tip turbine fan
Posted: Mon Jun 22, 2009 1:45 am
by Mike Everman
Hi Matt,
I can't imagine how this could possibly work (the patent, that is). The things people patent just amazes me sometimes. Not that it isn't a fun dream, but I don't think one would get too far into the calcs to find it's not practical.
Re: Pulse jet driven tip turbine fan
Posted: Tue Sep 15, 2009 5:17 am
by Ghrey
When I was 12ish I tinkered with such a design, Depending on suction to run the turbine. A teacher pointed out that gases ( such as air ) are too "stretchy" I think he said, to allow this system to operate effectively.
Even if a steady steady state operation was achieved, throttle change would almost inevitably lead to a stall, due to slow response time.
Just an opinion mind you but to me it is a bit too much like pushing a rope.
Cheers.