John Gibbons wrote:

Don,

    You might take a look at this site. I tried to find NSI on the web
but couldn't,  these guys supply NSI props out of Canada. Maybe Ken

knows

if NSI is still around. I flew a Glastar with one of these props on and
I liked it. What I liked is you can start up in a flat pitch so you're
not chucking gravel around and it is reversible. It is a little awkward
backing a taildragger up, but anything you can do that no one else can,
is fun. I plan on floats and I like to be able to back those up. There
is a lock out on them so you cannot go below 10 - 12 degrees of pitch
until you are running below 1000 RPM. The idea with this is you fly at
WOT and coarsen up the prop for max cruise but I had a feeling that the
 prop started to stall up around 24 - 26 degrees. The only thing I did
not like was that the pitch indicator was digital and the brushes on
the back tended to flutter giving wild fluctuations on the display.
I think an analogue display might be better or perhaps there is a
way of compensating electronically for the brushes.

http://www.westernaviation.bc.ca/engines.htm#Propellers

John

If NSI still has anything to do with it I would be very cautious indeed.
They have taken peoples money in the past and not delivered.
Engineair principles even went so far as to get a judgment against them.
If I ordered anything from them I would not pay for it in advance.
I would also be leery of accepting something from them COD until I proved
it to myself that it actually worked as advertised.

Paul Lamar

    Yep one complaint from the owner of that prop was the long delays in
getting their stuff. They did the whole firewall forward deal and they
waited a long time. A year or so ago I had trouble finding NSI on the web
and now I can't find them at all. This is another company offering NSI
products. Perhaps they have bought the rights. The quality and finish of the
NSI stuff is first rate from what I have seen although I am not too keen on
there spur gear PRSU's. Reversible pithch is a big thing for me, perhaps
Butch will change his mind and have one available by the time I'm ready for
one.

   One thing  I keep thinking of comes from the oil temperatures I observed
in the PRSU. It is a simple splash system with about 1 pint of oil. My
memory is fading but I think it typically ran around 110 degrees F,
considerably cooler than the engine oil. My thought is why not run the PRSU
oil independant of the engine either with a small pump off the metering pump
drive or the crank angle sensor drive, or a cam driven style.

    Would the lower temps help with the wear in the PRSU ?
    Is not the reduction one of the weak points in experimentals ?
    Would removing the heat of the PRSU from the engine cooling load not
help the overall cooling issues ?

John

 
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