----- Original Message -----
Sent: Saturday, September 13, 2003 11:08
PM
Subject: [FlyRotary] Re: Good news, Bad
news
Have you tested climb rate at lower speeds,
where drag is less important? Also, you could try reducing the size of the
inlet to the Radiator scoop to see if that reduces cooling drag, since you
have excess cooling available.
On the average RV-#, best rate of climb is about 100 kts,
or 120 mph. That's what it was on my RV-8, and also on a friend's
RV-3. I'm seeing best climb rate down around 80 kts, which was
about the best angle of climb on my RV-8. I think this is an indication
that drag is becoming too much of a factor in the higher speed
climbs. There's no questioning the
airframe. The normal performance of an RV-3 is well
known. I also can't doubt the power the engine is putting
out. It really slams you back in the seat on takeoff. I think
the only logical conclusion is that there's an overwhelming amount of
drag from the cowl.
As for the cooling drag, I do have a huge opening for an
air intake, but I just can't imagine that being the majority of the
problem. I'm afraid the whole cowl will need to be re-worked,
which means a smaller radiator, and a new intake manifold. I just
don't see any other option, since I'm really not interested in flying it
like it is.
Cheers,
Rusty
Hi,
Rusty....sorry you are having problems with drag, etc. I have the same
intake manifold as you, and the same throttlebody. I just ordered a
different manifold from Mazdatris (which is coming from Austrailia), and
I am going to first check to see if it fits as is. (see attached
photo) It is a simple 90 degree bend, with the throttle body mounting
vertical on it. If it is too high, I have a guy all lined up that can
bend the aluminum tubing, and another guy who is going to weld it up for me.
The advantage is, that the four intakes go into two right away, cast into the
first bend. Then from there, all I have to do is take it to my machinist who
will cut off the mounting flange and bore two holes for the aluminum tubing. I
will have that bent, and it will extend all the way across the top of the
engine, as close as possible to the engine, which will allow it to fit within
my cowling without having to make a bump in the cowling. Of course I will
have an adapter plate welded onto the other end of the tubes for the
throttlebody. They said it would take about a week and a half to get the
manifold, and that was a week ago. I will keep you posted. It
should be a fast and simple solution. It will be similar to the setup that
Paul Lamar is selling, but instead it will only have two intakes running over
the top of the engine, ending with a plate on which to mount our type of
throttlebody. Hope I expressed this clearly? This intake
will allow a turbo, of course. Take care, and good
luck.
Paul Conner,
Mobile, AL