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OK, now that's just not fair. We
"turbo" guys still are not catching you as it is... I guess it's time to
consider the C-drive as well. Rusty, how did your engine mount end
up? Did you put in the shims, or is your mount askew in the wrong
directing? Ed, same question.
I was hoping you meant that you were going to
abandon the turbo, but having a C drive AND a turbo would certainly be
interesting.
My mount is still offset to the left (wrong
direction). I could shim it to straight, but not to a right
offset. After flying it a while, and talking to Tracy (no offset in his
mount), I'm leaning toward leaving mine like it is. Tracy's description of
rudder usage on takeoff is the same as mine, so the best I can do is lessen
the problem a little. In cruise, it really doesn't take much of a trim tab
to take out all the yaw, and my feeling is that this isn't any more than
many RV's have anyway. In other words, I'm talking myself into believing
that the only time the offset is causing me a problem is during takeoff, and
climb.
Keep in mind though that this is a significant
issue. I can't use full throttle until I get a fair amount of airspeed to
make the rudder effective. Even then, it's a handful (or should I say
legful). The real question is how much of the problem is from the wrong
offset, and how much is just from the torque on that long prop. It could
be that no amount of correct offset would make up for putting that much
power/prop on an RV-3.
Now that you are turning in the 'right'
direction, you had the option of a metal prop. Did any of you strongly
consider that option?
No, I didn't consider it, but that's mostly
because I'm stupid. I'm still kicking myself for not realizing
that it was an option, even for the months that I waited for the new prop to be
made. Fortunately, now that I have thought about it, I wouldn't consider
it for my plane. The prop I had on the RV-8 was a Sensenich 72" x
87", which would be pretty good for the current engine. Unfortunately, it
weighed 40 pounds. The current monster prop weighs about 15 pounds.
Part of that weight was a spacer that came with the prop, which I'm
guessing weighed about 7 lbs.
I'm still waiting on parts to install the
TO4. I'm starting to think that a TO4 with the C-drive might make some
serious power (spray bars here I come). I am thinking that a shorter prop
may not produce as much p-factor and allow me to accept my left engine
offset.
Thoughts?
Since you asked... :-)
If you're determined to stay with a turbo, I
believe I'd suggest that you skip the C drive for now. You can get any
amount of power you want from the turbo, without the hassle and expense of
a new drive, and prop. You also won't have the problems of an incorrectly
offset mount. Worst case, you add the C drive later, if you prove you
"need" it.
To me, the real benefit of the C drive is being
able to optimize the NA engine power. I think it's far safer to
get 200 hp from a NA engine at 7000+ rpm, than to get it from a turbo engine at
any rpm. You could always approach this from another
angle, which would be to install the drive first, and see if you can live
without the turbo.
Now I
bet you're sorry you asked :-)
Rusty
(spending my day off with State Farm, and the
dentist)
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