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Re: REFLECTOR: Armpit scoops
Simon Aegerter wrote:
> > This arrangement lets
> >him remove his lower cowl without disconnecting his ducts from
> >the scoops.
Mark Machado started doing this back quite a few years ago. The factory liked
it so much thats whats on the XL's. The scoops attach to the wing root and go
right up behind the retract gear leg.
> > I would also like to move
> >the scoop leading edge nine inches in front of the cowl cut line.
> The opening of the scoop probably has to be a little less than the original
> scoop: first it is too big anyway (my CHTs are around 230-280F) and you get
> better efficiency more forward.
Yes, years ago Dan cut a set down from 43/4" to 33/4" from side of cowl and the
CHT's dropped 50 degrees and speed went up a few knots. I just cut a set down
from 6" too 41/2" and added 1" to the back of cowling because it was 11/2"
from prop. I also cut the scoops in the front 3/4"away from fuselage for the
boundry layer. I'll find out soon how this STD bird cools now that's it's
back too "Dan's" configuration.
> Cut the opening slanted about 15-30deg so
> that the opening is larger at high angles of attack!
This helps at cruise too because of the air coming up off the belly.
Close attention should also be paid to porting. Most of the new pletum set
ups I've seen have a sharp turn on the front side of the hole going into the
engine compartment (scat duct). This should be sloped mainly to open up the
restriction in size it causes. The nose oil cooler also works much better with
generous smooth and sloped porting in the exhast.