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Reason to go FP

P

prkaye

Well Known Member
I recently discovered a good reason to go with a FP when building your RV. It gives you a significant upgrade to look forward to! ;)
I'm actually serious. I can't afford/justify it any time soon, but I like the idea that I have a possible upgrade for a significant performance/efficiency boost in my back pocket for someday in the future (i.e. upgrade to CS prop). Maybe in 5 years or so I'll do that and maybe a significant panel upgrade at the same time and it will be almost like getting a new plane for a few thousand bucks :)
 
Besides...................with an F/P..........you can keep getting new ones... until you get the right compromise between climb & cruise!! :D

L.Adamson --- RV6A, Hartzell C/S
 
CP or FP? Which is better?

Your post sounds as if the constant speed is the holy grail of props. I am not so sure that is an accurate stance with our RV planes. Just as everyone in aviation knows airplanes are a compromise. No more so than this idea of constant speed props vs fixed pitch props. I acknowledge there are benefits to a constant speed prop but there are also some detriments that can very quickly offset those benefits.

Glad to hear that you are thinking of future "upgrades" for your airplane. In my case I am not so sure a constant speed prop would be an "upgrade" for my plane given the weight, complexity and expense of making that change.

The idea of switching props around to find the "best" for my plane sounds counter-productive. I like the idea of working with professionals like Craig Catto and having him optimize a prop for my airplane's needs from the onset.

Good luck with your future pursuits. LIVE LONG AND PROSPER!
 
Cost difference?

Can someone give a quick back of the envelope cost difference between a FP and CS setup? Including everything from prop, govenor, etc. Also, any ongoing difference in maintenance? I realize it will vary wildly between difference setups.

Just curious since I've always *thought* I wanted a CS but the reality is everything seems to cost more than you think and sometimes you have to make choices....
 
prkaye said:
I recently discovered a good reason to go with a FP when building your RV. It gives you a significant upgrade to look forward to! ;)
:)
Click to expand...

Phil, a buddy of mine just got his "CS" prop back from overhall. Cost him $4800, Ouch!!................ Just another "Reason to go FP". Originally, when I was building, I had the same idea about my 6A that you now have.
I now have 590 hours on my "FP" and it performs so well that I no longer have any desire to drop $10K and add 60 lbs to my "Baby"! ................. And, the debate goes on and on and on..............
 
ten grand?

Ten grand for that upgrade? Yikes. I guess maybe I saw that at some point during my build and that's part of why I went FP in the first place. Ten grand is a LOT of avgas.
.
 
This is a great point, and something I'm looking at. If you think about it, the RV has the same power as a C-172, yet half the weight and about 1/3 of the drag. So even an aggressive cruise prop is still going to out perform (by a large margin) what most would agree a is a very capable everyday/90% airplane.
 
Leaving aside the advantages of each... an "upgrade" could be adding a lot of extra work?

The cowling build/fit process is different for C/S v FP, and involves the prop and spinner. Someone who has done it might have more valuable feedback, but at a guess, you could be looking at some significant reworking of the cowling front end in your "upgrade".

Andy
 
twsurveyor said:
Phil, a buddy of mine just got his "CS" prop back from overhall. Cost him $4800, Ouch
Click to expand...

And a buddy of mine................just got his back for $1200. Re-painted, new seals, balanced, & yellow tagged. Looks just like new.

I suppose if your buddies prop needed a new hub, etc, then it could be that much.

In the meantime, unless I'm living & flying at sea level or just across the flatlands of middle America, .......and could care less about the feel of getty up & go instantly...........I might be okay with an F/P.

Nope, I probably still wouldn't..

L.Adamson --- RV6A
 
ExtraKatana said:
Like Sig Said.
We have so much power vs. the weight.
Like adding flaps to a cub....what's the point.
Click to expand...

There's a lot of points!

Have you never noticed the greatly enhanced "takeoff" performance..........when they add flaps to the Cub like aircraft. Aviat Husky, etc.? Kind of what a C/S does! Enhanced takeoff, quieter cruise, and much more options for landing.

L.Adamson --- RV6A, Hartzell C/S
 
L.Adamson said:
There's a lot of points!

Have you never noticed the greatly enhanced "takeoff" performance..........when they add flaps to the Cub like aircraft. Aviat Husky, etc.? Kind of what a C/S does! Enhanced takeoff, quieter cruise, and much more options for landing.

L.Adamson --- RV6A, Hartzell C/S
Click to expand...

I think he was being superfluous. While I'm a huge fan of a c/s prop, the more I really look at the cost of completion, it's forcing me to look at the real cost vs. benefit. While there is no doubt that a c/s prop will out perform a f/p... the f/p is such a performer already that I'm questioning myself if it's worth another 10 bills. That's a lot of Avgas or more avionics. Am I going to do aerobatics? Probably not anything aggressive. I can G myself stupid at work. What I want is a capable, comfortable, economical x/c bird that I can take friends up in and maybe do a loop or roll. Is the cost/benefit of a c/s prop going to get me there? I'm asking myself that more as I build.
 
Sig600 said:
I think he was being superfluous. While I'm a huge fan of a c/s prop, the more I really look at the cost of completion, it's forcing me to look at the real cost vs. benefit. While there is no doubt that a c/s prop will out perform a f/p... the f/p is such a performer already that I'm questioning myself if it's worth another 10 bills. That's a lot of Avgas or more avionics. Am I going to do aerobatics? Probably not anything aggressive. I can G myself stupid at work. What I want is a capable, comfortable, economical x/c bird that I can take friends up in and maybe do a loop or roll. Is the cost/benefit of a c/s prop going to get me there? I'm asking myself that more as I build.
Click to expand...

In my case, the C/S prop was budgeted before any other extras... above & beyond the kit & engine. I live in mountainous country, and was very use to the benefits of C/S. A good friend had an F/P equipped RV6A.........which gave me a good comparison. He always wished for a C/S, but had a solid crank engine.

L.Adamson --- RV6A
 
10k ??

how do you get that. a new Hartzell is under 7000 + 1200 for a governor - 2000 for the FP = 6200 or so difference.
 
Andy Hill said:
Leaving aside the advantages of each... an "upgrade" could be adding a lot of extra work?

The cowling build/fit process is different for C/S v FP, and involves the prop and spinner. Someone who has done it might have more valuable feedback, but at a guess, you could be looking at some significant reworking of the cowling front end in your "upgrade".

Andy
Click to expand...

Not so. The spacer you install behind the FP places the prop/spinnner in the same place as a CS prop/spinner.

As for the cost:
$430 for prop extension from Saber Mfg.
$2017 for the Catto FP 2 blade prop & spinner.
 
My buddies fly their RV's to the Idaho backcountry every summer (I'm going this year). Some of these backcountry strips are very short, boxed in, and during the summer reach DAs above 9 or 10K. They fly loaded with camping gear, food and clothes for two weeks at near max GW. Interestingly enough they all have FP props attached to 0-360's (carb) and never have an issue with performance, take-off, climb, landing or otherwise... Hmmmm guess the sea level argument isn't working out so well :)

Each has pros/cons

Sig - I sold my C/S prop from my first plane and bought some awesome avionics with Auto-Pilot and hooked up a really nice looking Sensenich wood prop and I'm able to keep up with my pals just fine. For $150 I can have it repitched (up to 3 times) so in a way this is a constant speed prop it just takes a bit longer to make adjustments.
 
Ken (Skipper!),
Exactly my point. In the several hundred hours of C-172 time I have (among others)... I only remember one time that the 160 HP, f/p prop wasn't enough. That was 4 guys, full fuel, on a hot day. Really, 4 stupid CFI's that didn't do a weight balance. So given that 160 HP f/p was enough to haul a 3800 # C-172 off of a 3600' DA day... 180 HP f/p prop would be more than adequate for an RV of 1/2 that weight. I don't ever plan on going to Leadville CO, but I have a feeling it would still work on a cool morning. My buddies f/p RV-6 with 160HP seems to perform JUST fine from up here in the high sierra's where summer DA can exceed 8K'. While a c/s is cool, I'm having a harder and harder time justifying the exponentially higher cost.
 
I'm definitely an advocate for a fixed pitch prop..

...for any of Van's two seaters BUUUUT also an advocate for a CS prop for the -10's. The two-seaters are incredibly nimble with a light prop like a Catto and are often faster in cruise than a CS...I've proved that more than once with my -6A and Catto combo.

I've also flown several -6's and -7's with CS props and the nose comes down much quicker and at a higher speed when you're landing. That said, I'd never consider a CS an "Upgrade" on a two -seater.

The -10 has the ability to carry a much bigger load of passengers and baggage, is also as heavy empty as the two-seaters' gross...almost, that a CS prop is really what it needs.

I think that the airplane mission and profile determines what it should have. My Air Tractor, for example, weighs 3700# empty and I've flown it at 8400# carrying 500 gallons of chemical and 100 gallons of Jet-A. No way a fixed pitch could get it off the ground on our 5,000' runway.

Best,
 
What I find amusing about these "choices" threads is that they quickly turn into people trying to justify why their own decision is the "right" one. Well, it probably was - for them. Not everyone has the same requirements, and therefore, trying to sell your choice to someone else as the correct decision for them is kind of silly, isn't it?

There are sound and valid reasons for both the fixed pitch and constant speed props. You get different advantages AND DISADVANTAGES from each of them. To say there is only one "smart" choice is to ignore the big picture of aviation. I have flown thousands of hours behind each kind of prop, and both work fine. Which you choose for a particular project will be determined by which corner of the aviation envelope you find yourself in at the time - and that includes consideration of performance, cost, maintenance, etc.

Enjoy the airplane you build, and accept the fact that others might enjoy a different combination.

Paul
 
Ironflight said:
What I find amusing about these "choices" threads is that they quickly turn into people trying to justify why their own decision is the "right" one. Well, it probably was - for them. Not everyone has the same requirements, and therefore, trying to sell your choice to someone else as the correct decision for them is kind of silly, isn't it?

There are sound and valid reasons for both the fixed pitch and constant speed props. You get different advantages AND DISADVANTAGES from each of them. To say there is only one "smart" choice is to ignore the big picture of aviation. I have flown thousands of hours behind each kind of prop, and both work fine. Which you choose for a particular project will be determined by which corner of the aviation envelope you find yourself in at the time - and that includes consideration of performance, cost, maintenance, etc.

Enjoy the airplane you build, and accept the fact that others might enjoy a different combination.

Paul
Click to expand...

Finally......Well said Paul!
 
prkaye said:
I recently discovered a good reason to go with a FP when building your RV. It gives you a significant upgrade to look forward to! ;)
I'm actually serious. I can't afford/justify it any time soon, but I like the idea that I have a possible upgrade for a significant performance/efficiency boost in my back pocket for someday in the future (i.e. upgrade to CS prop). Maybe in 5 years or so I'll do that and maybe a significant panel upgrade at the same time and it will be almost like getting a new plane for a few thousand bucks :)
Click to expand...

Yep, me too. It was a compromise to go FP and I figure in a couple of years when all the dust settles in my bank account, it'll be time for an engine overhaul and prop upgrade. Throw some new interior in it and some more avionics and you'll have a brand new airplane.
 
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