So I've been wanting to convert from fixed pitch to a constant speed on a 1997 RV-6A . Checked with Vans and the cowl is OK for constant speed. Barrett redid the engine in 1997 and they don't have records going back that far so they couldn't tell me if the overhauled crankshaft put in is solid or hollow (s/n 83877-1 M06M10P, balanced). What would be my next step? Remove prop and check? Any other considerations before I order new prop. It appears to have rear governor pad.
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Fixed pitch to Constant Speed
- Thread starter jhiggins
- Start date
You should be able to take the spinner off and view the end of the crankshaft through the hole in the center of the prop. If it is a solid crank, it will be apparent. The hollow crank has a plug fitted just inside the nose to the crank. That plug will need to be removed and a rear plug installed. I suggest that you remove the spinner to verify what type crank. If it is a hollow crank get an A&P to remove the plug and install the rear plug. Installing the rear plug can be a real pain in the ... and you can inadvertently cause damage that requires removal of the crank and sending it to Lycoming for repair. There is a small oil slinger tube that runs cross ways, in the center of the crank, just in front of the rear plug. Any damage to that tube requires factory replacement. Good luck. Dan from Reno
Constant speed
The E series 0 320's with the 0 235 front main bearing will not support a constant speed prop. Not all E series have the 235 bearing.
Regarding the accessory case if it doesn't have the governor pad machined it is not a big deal to have that done.
The solid shaft engines were mostly 0 360 A4 series. A few 0 320's.
The E series 0 320's with the 0 235 front main bearing will not support a constant speed prop. Not all E series have the 235 bearing.
Regarding the accessory case if it doesn't have the governor pad machined it is not a big deal to have that done.
The solid shaft engines were mostly 0 360 A4 series. A few 0 320's.
WHY CHANGE?
my business partner and i both built RV7's together. identical io360's, his cs, mine fixed. 1st. my prop was $8000 cheaper, not even counting the governor, 80#'s +/- lighter.
now he gets airborn about 100' faster, climbs to alt quicker, when i catch him he is constantly asking me to slow up so he can catch up. what am i missing? what is so great about a cs prop?
my business partner and i both built RV7's together. identical io360's, his cs, mine fixed. 1st. my prop was $8000 cheaper, not even counting the governor, 80#'s +/- lighter.
now he gets airborn about 100' faster, climbs to alt quicker, when i catch him he is constantly asking me to slow up so he can catch up. what am i missing? what is so great about a cs prop?
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Fixed vs Constant Speed
This has been hashed out here a lot over the last 10 to 12 years. A lot depends on where you are based and where your travels take you, imho!
I had a fixed pitch on my 6A and the first time I flew to Denver from my home base in Texas I was convinced to change to constant speed.
Upon departing KBJC on a warm afternoon, full fuel, and near our gross weight, I had a hard time out climbing a Cessna doing touch and go's on the parallel runway. Granted, he also had two on board but probably wasn't loaded heavy for a training flight.
Got home, converted over to constant speed, and have never regretted it.
On our next trip to Denver, same scenario. Near gross, full fuel, heat of the day only this time it was a Mooney on the parallel for departure. I left that Mooney behind, probably wishing he had an RV.
Actual performance difference between the two props was around 1200fpm in a high density altitude situation.
So you be your own judge in deciding how much "total performance" you need!
This has been hashed out here a lot over the last 10 to 12 years. A lot depends on where you are based and where your travels take you, imho!
I had a fixed pitch on my 6A and the first time I flew to Denver from my home base in Texas I was convinced to change to constant speed.
Upon departing KBJC on a warm afternoon, full fuel, and near our gross weight, I had a hard time out climbing a Cessna doing touch and go's on the parallel runway. Granted, he also had two on board but probably wasn't loaded heavy for a training flight.
Got home, converted over to constant speed, and have never regretted it.
On our next trip to Denver, same scenario. Near gross, full fuel, heat of the day only this time it was a Mooney on the parallel for departure. I left that Mooney behind, probably wishing he had an RV.
Actual performance difference between the two props was around 1200fpm in a high density altitude situation.
So you be your own judge in deciding how much "total performance" you need!
My last RV was CS and this one is fixed pitch. I really miss having a CS. So it is not really a matter of why do it, i was just wondering about the logistics. The engine was a o360 c1e converted to a dynafocal. It was completely redone by barrett due to a prop strike i believe with overhauled crankshaft. So i,m pretty sure it will support the CS but i didn' t know what else was involved.
Bob Martin
Well Known Member
More
I hesitate to bring this up and spoil your fun, but it happened to me and it could happen to you as well, given you have an overhauled engine.
Mel is correct about the nose area. The Clamshell bearing in the nose has to have the hole in it to allow oil to flow through it to the crank. But...also, in some solid crank engines there has been a exit hole drilled in the opposite side of the case to allow oil to drain back into the sump. A sharp shop, which Barrett is, would plug this hole if a hollow crank in installed. But if the build papers say FP setup....then it could get overlooked. This hole keeps the nose from building pressure to move the prop.
There is a simple test to do on the nose to check for this "hole" or any other issue that would keep it from working. I say this because we started on the CS conversion and wound up doing a teardown to fix and that turned into a complete OH.....so a little homework will make you feel confident that everything is ok before you plunge in.
Good Luck....you will love the CS prop.
Governor pad...adapter drive.
Firewall recess...
New prop cable and install...
Governor and cable bracket.
SS line from governor to nose.
MP gauge if you don't have already.
Prop and spinner.
New W&B.
I hesitate to bring this up and spoil your fun, but it happened to me and it could happen to you as well, given you have an overhauled engine.
Mel is correct about the nose area. The Clamshell bearing in the nose has to have the hole in it to allow oil to flow through it to the crank. But...also, in some solid crank engines there has been a exit hole drilled in the opposite side of the case to allow oil to drain back into the sump. A sharp shop, which Barrett is, would plug this hole if a hollow crank in installed. But if the build papers say FP setup....then it could get overlooked. This hole keeps the nose from building pressure to move the prop.
There is a simple test to do on the nose to check for this "hole" or any other issue that would keep it from working. I say this because we started on the CS conversion and wound up doing a teardown to fix and that turned into a complete OH.....so a little homework will make you feel confident that everything is ok before you plunge in.
Good Luck....you will love the CS prop.
Governor pad...adapter drive.
Firewall recess...
New prop cable and install...
Governor and cable bracket.
SS line from governor to nose.
MP gauge if you don't have already.
Prop and spinner.
New W&B.
Christopher Murphy
Well Known Member
Cessna not immune to DA
My grossed out 160hp fp rv4 out climbs any cessna at the DA we have in Colorado..on the hottest day i never see less than 800 fpm. I doubt a constant speed would do 1200 fpm more. Infact if I climb at my best speed my ROC would be very close to any cs prop.
Cm
My grossed out 160hp fp rv4 out climbs any cessna at the DA we have in Colorado..on the hottest day i never see less than 800 fpm. I doubt a constant speed would do 1200 fpm more. Infact if I climb at my best speed my ROC would be very close to any cs prop.
Cm
Christopher Murphy
Well Known Member
Missed the point
The cs provides marginally improved accel and climb performance..it will not out perform my catto 2 blade at the top end...so its not the best of both worlds..it a compromise...you are trading weight, top end, handling, smoothness,money, maint costs for marginal fpm increase...
We all decide what we want...
But...my point was that cesnnas are not imune to DA issues. The poster says his rv got out climbed in the pattern by a cessna..as if his rv suffered from the DA and the cessna didnt..
Cm
The cs provides marginally improved accel and climb performance..it will not out perform my catto 2 blade at the top end...so its not the best of both worlds..it a compromise...you are trading weight, top end, handling, smoothness,money, maint costs for marginal fpm increase...
We all decide what we want...
But...my point was that cesnnas are not imune to DA issues. The poster says his rv got out climbed in the pattern by a cessna..as if his rv suffered from the DA and the cessna didnt..
Cm
