What engine or motor could make a fan rotate at really realy fast speeds?

Question

it needs to be portible and about the size of a tire or big tire i need it to propell a fan that is any size from tire size or double tire size and be able to lift about 90 pounds plus the weight of the engine or motor

Answer 1

If your trying to make a flying platform I suggest that you look up the VZ-1 Pawnee.  A flying platform invented by Steven Hiller in the mid 1950's for the US Army.

The Pawnee is a 5 foot diameter  ducted fan on which the operator stands on top over a screened inlet.   The Pawnee used two counter rotating props run by Nelson 2-cycle engines.

From the Hiller Mueseum:

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Complementing Zimmerman’s "kinesthetic" theories, the Hiller Advanced Research Division (A.R.D.) incorporated a five foot fiberglass round wing, (ducted fan) with twin counter rotating coaxial propellers powered by two 44hp/4000 rpm, four cylinder opposed, two-cycle, Nelson H-59 Engines. The Nelson engine was the first two-cycle engine certified by the FAA for aircraft use. Utilizing the Bernoulli principle, 40% of the vehicle's lift was generated by air moving over the ducted fan's leading edge. The remaining 60% of lift was generated by thrust from the counter rotating propellers

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Answer 2

If you are talking about a fan lifting 90 pounds, plus the weight of its engine, you are talking about a helicopter.

There are some collapsible helicopters which can fit into a backpack, but they aren't cheap, and you need a special license to fly one.

Answer 3

If you are talking direct lift (ie. the fan provides a downward thrust which is the sole means of lift), well then good luck with that!  There have been many attempts at making a backpack sized machine to carry one pilot up, none have really worked.  There are some very small helicopters but all are quite a bit larger than what you are describing.

Answer 4

For a helicopter, you do not want a fast rotation speed.

A helicopter is controlled by changing the angle of the blades with rotation. That is, the angle is different depending on where the blade is in its 360 degrees of rotation.

This requires a lot of complicated mechanical linkages that have to work as the blades rotate. Make the blades rotate very fast, and the design of these linkages gets a lot more complicated.

Answer 5

billruss is right, if you need uplift force rotation speed is secondary. What you need is area (wide, long blades) and attack angle. A tire-sized fan is just too small to generate any sizable uplift force.

And BTW, it doesn't matter if the blades are above or below the weight to be lifted -it's still the same concept as a helicopter.