Van's Air Force
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I Don't Get It - FP vs CS
- Thread starter Mark7986
- Start date
pazmanyflyer
Well Known Member
To be honest...
...and not trying to be rude but you don't have to get it. Personal choice for many reasons. Just like yours.
...and not trying to be rude but you don't have to get it. Personal choice for many reasons. Just like yours.
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marchudson
Well Known Member
Mark
Climb performance and in flight speed brakes. At least these are the two reasons that I went with the CS prop. Others might have different reasons.
Climb performance and in flight speed brakes. At least these are the two reasons that I went with the CS prop. Others might have different reasons.
You ask why everyone think a C/S prop is NECESSARY. Short answer is, Everyone doesn't. Many people do like it, and to their credit, it is a great item, but it is not necessary.
As others have said, that's the beauty of the Experimental world. If you want it great, if you don't, then that's great too.
The C/S prop has advantages. It has disadvantages. Your choice.
There have been many, many RVs flying for over 40 years with F/P props and they perform wonderfully.
As others have said, that's the beauty of the Experimental world. If you want it great, if you don't, then that's great too.
The C/S prop has advantages. It has disadvantages. Your choice.
There have been many, many RVs flying for over 40 years with F/P props and they perform wonderfully.
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[email protected]
Well Known Member
Toobuilder
Well Known Member
NickAir
Well Known Member
RV's are experimental. Do what you want.
Just don't get sucked into an old debate
Different configuration on anything is because people like different things.
I have had both C/S and F/P, like many other pilots here.
They both have advantages and disadvantages for different missions.
Just meet your mission and your good to go...
Just don't get sucked into an old debate
Different configuration on anything is because people like different things.
I have had both C/S and F/P, like many other pilots here.
They both have advantages and disadvantages for different missions.
Just meet your mission and your good to go...
Brantel
Well Known Member
A friend of mine usually fly alongside another friend that has a CS. We both have FP. All three have 180hp engines.
His has some differences over our FP planes.
1. He can take off ~10% sooner than us.
2. He can climb at a greater rate than us.
3. He looks like he threw a boat anchor out when he pulls the power off.
4. He has no problems with his empty CG where I have to limit baggage.
Top speed is a wash, slight advantage to the FP but it all depends on FP RPM and his RPM and MP.
While we can't climb at his rate, we can go faster while he is climbing. Net result is we can basically end up in the same place at the same time by leveraging that speed. We just do it at a shallower angle. He gets to altitude quickly but then must catch up to us.
If he is in front of us on a group arrival, we must give him room or we will eat his lunch on base and final. He can slow down instantly and we cannot.
His has some differences over our FP planes.
1. He can take off ~10% sooner than us.
2. He can climb at a greater rate than us.
3. He looks like he threw a boat anchor out when he pulls the power off.
4. He has no problems with his empty CG where I have to limit baggage.
Top speed is a wash, slight advantage to the FP but it all depends on FP RPM and his RPM and MP.
While we can't climb at his rate, we can go faster while he is climbing. Net result is we can basically end up in the same place at the same time by leveraging that speed. We just do it at a shallower angle. He gets to altitude quickly but then must catch up to us.
If he is in front of us on a group arrival, we must give him room or we will eat his lunch on base and final. He can slow down instantly and we cannot.
FP vs CS
I totally agree! Surely this guy is just trying to stir things up on the forum and he has succeeded. It's like asking "Do you prefer a Garmin portable or an iPad for VFR flight".
Opinions start flying and the posts to the forum go up, woo hoo! BTW....I STILL prefer my iPad!
I totally agree! Surely this guy is just trying to stir things up on the forum and he has succeeded. It's like asking "Do you prefer a Garmin portable or an iPad for VFR flight".
Opinions start flying and the posts to the forum go up, woo hoo!
BTW....I STILL prefer my iPad!as a pilot i like C/S because i have more control over the flight profile, i.e, better climb / cruise / descent, better fuel economy, better for acro and formation and of course the most important aspect is another knob to play with
as a mechanic / owner i dislike the C/S because it more expensive to purchase, a PITA to install and remove, higher cost of maintenance and another reason not to let the airplane sit for too long (seals dry out and oil seeps)
That being said: I am still gonna put a C/S on the front of my -8 but intstead of goin with the IO-390 i dream of, Im doin an IO-360 180hp
as a mechanic / owner i dislike the C/S because it more expensive to purchase, a PITA to install and remove, higher cost of maintenance and another reason not to let the airplane sit for too long (seals dry out and oil seeps)
That being said: I am still gonna put a C/S on the front of my -8 but intstead of goin with the IO-390 i dream of, Im doin an IO-360 180hp
benbell4140
Well Known Member
I would buy the car with one speed if it cost 1/4 the price and performed within 5% of a car with multiple speed transmission and had virtually no maintenance. We will all end up at our destination with a separation measured in a few minutes...
gerrychuck
Well Known Member
I would if I could do everything I needed to in my car using only a 600 rpm power band...
What is the price differential? If your mission is to go cross country isn't it better to just go fp? Formation flying does sound like fun though making me want to go with a 390 cs hotrod. It all comes down to money
Don't let anyone tell you formation requires a CS - pure bunk!
ronschreck
Well Known Member
OK, there's formation (A):
And then there's formation (B):
Neither requires a CS prop, but at some point between A and B you will wish you had one.
(How many times must we have this discussion?)
as often as is required...
Formation A = Saturday morning join up with friends for breakfast and a quick game of tail-chase... FP or CS does not matter as long as lead understands the performance limits.
Formation B = Airshow performers who need maximum performance...a niche at best.
If you are going from A to B and B's flight memebers all have CS then you probably should also. What if you go from A to B and B has all FP?
ronschreck
Well Known Member
It's your airplane. Do what you want.
B=a niche at best or the best niche. It's up to you!
B, all with FP... You better be careful! You can all overspeed all your engines at once.
B=a niche at best or the best niche. It's up to you!
B, all with FP... You better be careful! You can all overspeed all your engines at once.
B, all with FP... You better be careful! You can all overspeed all your engines at once.
Cool, wouldn't hurt a thing and would sound awesome.
Remember the 'French Connection' or the 'Red Devils'? Pretty top level FP prop formation aerobatics.
http://www.youtube.com/watch?v=0fXl4xDV6-k&feature=results_video&playnext=1&list=PL8CB29C38037A3C1B
smokyray
Well Known Member
No weapon too simple, for a brave man...
Age old question, same answer, it depends.
Post 9/11 my F16 Squadron had eleven RV4's (including mine) owned and flown by squadron pilots before we deployed to Iraq in 2002. It was so unique I wrote an article for Sport Aviation and somehow they published it! FP and C/S were well represented, six vs five. The FP airplanes were purchased that way mainly due to availability and budgetary constraints.
The guys flying them were full up modern combat fighter pilots who operated the airplanes safely but at the very upper edge of their envelope. Formation flying (tactical and non), short grass strips, day, night (NVG's), acro, dogfights (lots of dogfights!) didn't matter. The prop made little difference in planning and execution in every category except in glide ratio contingency planning. One pilot noted that his FP RV4 could glide 10 miles for every 5K feet lost in a power off glide. The C/S was less than half that. The F16 free of external stores will glide further. Note to self...
For guys making the choice, look at cost vs return for YOUR type flying and budget. C/S is a nice option but it requires money, more moving parts and is more expensive to repair. It's not a go-no-go. A good pilot can operate a FP RV in any arena with equal aplomb as a C/S, it just requires a bit of finesse.
Smokey
Of course we weren't doing doing loops to music at airshows...
Age old question, same answer, it depends.
Post 9/11 my F16 Squadron had eleven RV4's (including mine) owned and flown by squadron pilots before we deployed to Iraq in 2002. It was so unique I wrote an article for Sport Aviation and somehow they published it! FP and C/S were well represented, six vs five. The FP airplanes were purchased that way mainly due to availability and budgetary constraints.
The guys flying them were full up modern combat fighter pilots who operated the airplanes safely but at the very upper edge of their envelope. Formation flying (tactical and non), short grass strips, day, night (NVG's), acro, dogfights (lots of dogfights!) didn't matter. The prop made little difference in planning and execution in every category except in glide ratio contingency planning. One pilot noted that his FP RV4 could glide 10 miles for every 5K feet lost in a power off glide. The C/S was less than half that. The F16 free of external stores will glide further. Note to self...
For guys making the choice, look at cost vs return for YOUR type flying and budget. C/S is a nice option but it requires money, more moving parts and is more expensive to repair. It's not a go-no-go. A good pilot can operate a FP RV in any arena with equal aplomb as a C/S, it just requires a bit of finesse.
Smokey
Of course we weren't doing doing loops to music at airshows...
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When you consider that Van has always said that a fixed pitch propeller has been a challenge due to the large speed range, being able to use a C/S prop seems to be the obvious solution.
I know that some of the composite and wood props flex and give etc, however if you want to take advantage of the total performance that RV's give, I think the added expense and complexity of the C/S prop is well worth it.
However, that said, if your budget and chosen aims of the finished aeroplane tend towards FP - go for it.
My aeroplane partner, Mark, built a 7, FP. Great aeroplane, great build and finish.
He had offers for his, I wanted to sell half of mine when I finished mine and we ended up half and half in mine.
I have an IO-360, MT 3 Blade.
It looked like a perfect match - so I gave Mark a ride in mine.
I think the phrase rhymed with Clucking Bell when I opened her up on the runway...............
Ironically - one of the issues of the MT is that we seldom land fully fine - usually set to around 2500 rpm, gives a much sweeter flare and there is plenty of power in the event of a missed.
Horses for courses - it's just that ours is a whole lot more fun
I know that some of the composite and wood props flex and give etc, however if you want to take advantage of the total performance that RV's give, I think the added expense and complexity of the C/S prop is well worth it.
However, that said, if your budget and chosen aims of the finished aeroplane tend towards FP - go for it.
My aeroplane partner, Mark, built a 7, FP. Great aeroplane, great build and finish.
He had offers for his, I wanted to sell half of mine when I finished mine and we ended up half and half in mine.
I have an IO-360, MT 3 Blade.
It looked like a perfect match - so I gave Mark a ride in mine.
I think the phrase rhymed with Clucking Bell when I opened her up on the runway...............
Ironically - one of the issues of the MT is that we seldom land fully fine - usually set to around 2500 rpm, gives a much sweeter flare and there is plenty of power in the event of a missed.
Horses for courses - it's just that ours is a whole lot more fun
Set to 2500 RPM in the flair at idle (unless you're carrying a good bit of MP) should set the prop against the fine pitch stops anyway....except if you're prop is Couterweighted? Just curious!
Cheers,
Stein
Don't know the answer - it behaves differently and doesn't disc as much.
Tried it at various settings and it makes a difference.
I know what you are saying and it makes me think what is happening - all I know is when we have the prop out a bit it lands sweeter.
Used to do the same on a C 206 I flew for skydiving, noise was a lot less on final, missed was OK as you were empty, landing was sweet.
Tried it at various settings and it makes a difference.
I know what you are saying and it makes me think what is happening - all I know is when we have the prop out a bit it lands sweeter.
Used to do the same on a C 206 I flew for skydiving, noise was a lot less on final, missed was OK as you were empty, landing was sweet.
woodmanrog
Well Known Member
Constant speed prop setup, about 15K plus maintenance. FP Catto prop, about 2K. Difference, about 13K. Fuel about $5+per gallon. Difference, 2600 gallons of fuel. I think I'll stay with my FP prop.
C-FAH Q
Well Known Member
How many hartzells did you price in that figure?
Bottom line, different strokes for different folks. No one is right, no one is wrong. Do what you like or want and keep yourself happy, everyone else don't matter when your flipping the bill.
NickAir
Well Known Member
Endless debate
Woodman makes a real point about cost vs. benifit. This debate is endless.
I LIKED the simplicity and cost of Fixed pitch which I had on my -6. (Smile)
I LOVE the benifits and control of Constant Speed on my -7. Although it does cost more, it is worth every penny to me and other I have talked with. (Bigger Smile)
Resolution- Just do what you want and get in the air. It is all fun.
Woodman makes a real point about cost vs. benifit. This debate is endless.
I LIKED the simplicity and cost of Fixed pitch which I had on my -6. (Smile)
I LOVE the benifits and control of Constant Speed on my -7. Although it does cost more, it is worth every penny to me and other I have talked with. (Bigger Smile)
Resolution- Just do what you want and get in the air. It is all fun.
LifeofReiley
Well Known Member
L.Adamson
Well Known Member
Nope, just add maintenance and you're there...
Not hardly......
But to believe it..... just makes the F/P owners feel better...
I'd never want an RV without a C/S..........never, never, never......
LifeofReiley
Well Known Member
Not hardly......
But to believe it..... just makes the F/P owners feel better...
I'd never want an RV without a C/S..........never, never, never......
Then we would never want you to be with out...
L.Adamson
Well Known Member
Then we would never want you to be with out...
Actually, I am at the moment. It's why my RV doesn't fly anymore. The downside of C/S, is that they cost more in a prop strike.....
LifeofReiley
Well Known Member
just wait till the C/S prop starts spitting grease all over the windshield, take it off and send it in for repairs... drop your pants.
I'd think that...
.... when a carowner has tried automatic transmission, he'd never want to go back to manual gearshifts anymore...
That's the case for me at least...
Get a ride in a -7 with a C/S prop: do some short field takeoff and landings, some acro and then decide....
.... when a carowner has tried automatic transmission, he'd never want to go back to manual gearshifts anymore...
That's the case for me at least...
Get a ride in a -7 with a C/S prop: do some short field takeoff and landings, some acro and then decide....
Flyguytki
Well Known Member
Again personal preference, I would rather have a manual transmission over automatic any day. But that right theres proves the point. It all what you want, if you want simple, you cant get much more simple than one lever for power, push forward go fast pull back slow down.
-david
NickAir
Well Known Member
C/S or F/P
The simplicity of a fixed pitch has benefits:
- no moving parts
- no grease
- no leaking Zerk's
- no down time for rebuild
- no high $$ for rebuild
- no problem out performing spam cans w/ your F/P
- Top end speeds are same as F/P
- There are fixed pitch props that flex flatter at max rpm when airspeed is low, (for better climb performance.) This will never compete with a C/S although appears to be a great compromise.
- Tri blade F/P is supposed to provide more thrust at lower airspeed although it may be slightly less efficient.
- Tri blade creates higher prop clearance to ground.
If a RV pilot wants more performance at take off and climb then you can still stay with a F/P by going with a tri blade and/or a higher pitch. This will limit the top end to a lower speed as a direct trade off for the higher performance on take off and climb. This is common with small power bush planes for reasons mentioned above.
The simplicity of a fixed pitch has benefits:
- no moving parts
- no grease
- no leaking Zerk's
- no down time for rebuild
- no high $$ for rebuild
- no problem out performing spam cans w/ your F/P
- Top end speeds are same as F/P
- There are fixed pitch props that flex flatter at max rpm when airspeed is low, (for better climb performance.) This will never compete with a C/S although appears to be a great compromise.
- Tri blade F/P is supposed to provide more thrust at lower airspeed although it may be slightly less efficient.
- Tri blade creates higher prop clearance to ground.
If a RV pilot wants more performance at take off and climb then you can still stay with a F/P by going with a tri blade and/or a higher pitch. This will limit the top end to a lower speed as a direct trade off for the higher performance on take off and climb. This is common with small power bush planes for reasons mentioned above.
pierre smith
Well Known Member
In my opinion, Craig Catto, although they're really composite but the most bang for the buck.
Best,
I think you mean "lower pitch" for take-off performance. Lower pitch allows the engine to turn up faster thereby producing more power.
PerfTech
Well Known Member
Best FP prop
I second that! Craig Catto is one of the nicest, most sincere, helpful and accommodating people you will ever meet and makes a fabulous product. He will work with you to be certain you have the perfect propeller for your airplane. Very hard to improve on that! Allan
I second that! Craig Catto is one of the nicest, most sincere, helpful and accommodating people you will ever meet and makes a fabulous product. He will work with you to be certain you have the perfect propeller for your airplane. Very hard to improve on that! Allan
P
paul mosher
C/S
Grease on windshield? High maintenance? I've used C/S props for years and never experienced either problem. Get what you want.
It'll be cheaper to buy a C/S than buying a F/P and changing your mind later.
But get what you want.
Grease on windshield? High maintenance? I've used C/S props for years and never experienced either problem. Get what you want.
It'll be cheaper to buy a C/S than buying a F/P and changing your mind later.
But get what you want.
additional workload for CS?
I have flown almost always with a FP prop. I flew some in a 182 that had a CS, but I didn't operate the prop since I didn't have experience with one - the plane's owner did the prop adjustments. That was several years ago and I don't remember much about it. How much more complex is it for a low time pilot? If I remember correctly, LSA does not allow it for that reason. I plan to go with a fuel injected engine to reduce the leaning needs and chance of error and engine repairs. The cost is an issue too and my major flight profile is traveling to visit kids and grandkids. I like the idea of increased climb and the ability to slow down getting in and out of smaller airports, but the -9 with a 360 or a 320 will not have any performance problems for sure with either type of prop.
Does the extra knob add that much workload for a low time pilot? It may be a question that may not have an answer more than a standard transmission - vs - auto would have. I appreciate the expertise here - it is hard to find something that people don't know about on this forum!
I have flown almost always with a FP prop. I flew some in a 182 that had a CS, but I didn't operate the prop since I didn't have experience with one - the plane's owner did the prop adjustments. That was several years ago and I don't remember much about it. How much more complex is it for a low time pilot? If I remember correctly, LSA does not allow it for that reason. I plan to go with a fuel injected engine to reduce the leaning needs and chance of error and engine repairs. The cost is an issue too and my major flight profile is traveling to visit kids and grandkids. I like the idea of increased climb and the ability to slow down getting in and out of smaller airports, but the -9 with a 360 or a 320 will not have any performance problems for sure with either type of prop.
Does the extra knob add that much workload for a low time pilot? It may be a question that may not have an answer more than a standard transmission - vs - auto would have. I appreciate the expertise here - it is hard to find something that people don't know about on this forum!
