Spacing of two turbines?

[debequechute]

Two 5' turbines, I measured 540 RPM in a 10MPH wind last night if it matters (no load). I plan on mounting them side-by-side on the same tower (offset of course for furling). I'm thinking at least a foot apart and counter rotating so the tips in the center are headed in the same direction. Think that's enough to keep them from interfering with each other?

[nothing to lose]

Funny how people get thinking close to the same type ideas about the same time.

I just posted about a aircraft gennie I geuss while you were posting this 2 gennie post.

 I am thinking for mine about 3' maybe, but that's to mount 4 gennies to look like a aircraft. 2 on each wing.

[finnsawyer]

Probably not.  The problem is the vortices created off of the tips.  These spread out like the wake of a boat only in three dimensions.  You may have seen pictures of them off of airplane wings on TV.  Can be nasty things for airplanes as they reduce lift.  And therein lies the problem for you.  Putting the turbines too close can affect the performance of both.  Since your turbines are relatively small, you could do some tests by mounting them on the front of a vehicle and measuring performance for different spacings.  You could even gear them together to try to minimize interactions.  One way to reduce the vortices is to make the tips of the blades elliptical like the WWII Spitefire wings.  Another might be to put a ring or hoop around the outside of the blade assembly.  It gets pretty complicated.  Anybody got a wind tunnel?    

[elvin1949]

i think Jerry was working on a wind tunnel

a while back.

later

elvin