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  #41  
Old 03-04-2016, 03:47 PM
sblack sblack is offline
 
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I have a friend with a 7A and CS, O360. My neck hurts when we takeoff. I have never felt acceleration like that in a light airplane. You will get better performance no doubt. But the OP was about slowing down and it being easier for a new TW pilot. I don't foresee any difference once you've had some training. I would put CS in my 4 if I had the dough, but I don't so I know a FP will still be a great airplane compared to anything out there that is non RV.
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  #42  
Old 03-04-2016, 07:05 PM
rightrudder rightrudder is offline
 
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Quote:
Originally Posted by sblack View Post
I have a friend with a 7A and CS, O360. My neck hurts when we takeoff. I have never felt acceleration like that in a light airplane. You will get better performance no doubt. But the OP was about slowing down and it being easier for a new TW pilot. I don't foresee any difference once you've had some training. I would put CS in my 4 if I had the dough, but I don't so I know a FP will still be a great airplane compared to anything out there that is non RV.
I totally relate, Scott. I did my transition training in a 7A set up just as you describe. On my first takeoff roll, it jumped so hard that I failed to push the throttle in all the way (which my instructor quickly corrected). Crazy acceleration!

That said, I'm very happy with my FP Catto. It climbs very well, and I just like the lightness and simplicity of the setup...less to go wrong and maintain.
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  #43  
Old 03-19-2016, 02:25 PM
Robb Robb is offline
 
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Constant speed is the only way to go unless cost is an issue.
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  #44  
Old 03-19-2016, 04:45 PM
David-aviator David-aviator is offline
 
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CS performs better on take off and climb, costs more, weighs more and is most satisfactory to anyone going that route.

FP performs better than most span cans, costs less, weighs less, and is most satisfactory to anyone going that route.

Been there with both and liked both. It is a matter of personal choice and circumstances when deciding.

You can't go wrong either way with a RV.
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  #45  
Old 03-19-2016, 04:50 PM
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Sam Buchanan Sam Buchanan is online now
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Quote:
Originally Posted by Robb View Post
Constant speed is the only way to go unless cost is an issue.
Well...I guess that means the thousands of RVers with fixed-pitch props are financial sub-standard members of the community who can't afford the best......

That's the problem with making absolute, blanket statements....
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  #46  
Old 03-19-2016, 07:27 PM
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vlittle vlittle is offline
 
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Given a certain dollar and weight budget, Is it better to have a heavier, more powerful engine with a fixed pitch, or a lighter, less powerful engine with a heavier CS Prop?

I think it is a top speed vs climb rate tradeoff.
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  #47  
Old 03-19-2016, 09:01 PM
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n5lp n5lp is offline
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Quote:
Originally Posted by Robb View Post
Constant speed is the only way to go unless cost is an issue.
Boy do I ever feel the fool. The enjoyment of the last 17 years of flying an elegantly simple and efficient design was just an illusion.

Maybe with a heavier, more expensive and more complicated propeller that wouldn't let me fly any faster but would accelerate better during the takeoff roll, I would actually be having fun.
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  #48  
Old 03-19-2016, 09:05 PM
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Carl Froehlich Carl Froehlich is online now
 
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Quote:
Originally Posted by vlittle View Post
Given a certain dollar and weight budget, Is it better to have a heavier, more powerful engine with a fixed pitch, or a lighter, less powerful engine with a heavier CS Prop?

I think it is a top speed vs climb rate tradeoff.
The thumb rule a few years ago was a O-320 with CS prop was better compromise for an RV than an O-360 with FP prop.

The idea was the CS prop made up for the loss of power on takeoff (the smaller engine could produce full power while the larger FP engine could not get full power RPM), and the smaller engine still had a boat load more power than the majority of us use in cruise.

If the majority of your flying is max power, 2700 RPM cruise then just pick a FP prop that does that with whatever engine your wallet can support. I suspect few fly like this.

Carl (had a FP RV-8A and changed to a CS prop after 300 hours - and was very happy with the upgrade).
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  #49  
Old 03-19-2016, 09:33 PM
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N941WR N941WR is offline
 
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Like everything else in this world, it depends.

I have an RV-9 with a Catto FP "Ubercruiser" prop, spun by a "stock" ECI O-360.

A year ago I led a five ship formation flight out of a 5,000' county airport and was the only FP plane of the lot.

All the other planes had IO-360's or better so during our briefing we discussed what speed I should use for the climbing left turn. All four wingmen were experienced card holding formation pilots and all four said to climb at 120 knots and make the turn as they would catch me.

What none of us took into consideration was how well the 9's wing works and at 120 knots they kept asking me to "give 'em some" until I was down below 100 knots and they could join up.

With 700+ hours on my plane, the only time I wish I had a CS prop was when flying formation with someone who forgets and cobs the throttle and when landing with a bunch of CS prop'ed airplanes. It would be nice to have that big speed brake up front. However, for normal flight operations, I am very content with the FP Catto up front.
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  #50  
Old 03-20-2016, 08:30 AM
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Dbro172 Dbro172 is offline
 
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Quote:
Originally Posted by Carl Froehlich View Post
The thumb rule a few years ago was a O-320 with CS prop was better compromise for an RV than an O-360 with FP prop.

The idea was the CS prop made up for the loss of power on takeoff (the smaller engine could produce full power while the larger FP engine could not get full power RPM), and the smaller engine still had a boat load more power than the majority of us use in cruise.

If the majority of your flying is max power, 2700 RPM cruise then just pick a FP prop that does that with whatever engine your wallet can support. I suspect few fly like this.

Carl (had a FP RV-8A and changed to a CS prop after 300 hours - and was very happy with the upgrade).
There is not much cost difference between a 320 and 360, maybe $1500. The difference from FP to CS is $5k and up.
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