Hartzel BA vs old style Hartzel prop

I assume this is somewhere on the site but my search hasn't turned it up. I'm trying to shave something off the cost of an RV-8 without giving up too much performance and the prop, being a big ticket item, offers an opportunity. I have located a 10 year old, old style, zero time refurbished 72", B hub, Hartzel prop for about half what a new BA prop would cost. Not too surprisingly, the seller of the prop said, other than looks, minimal difference in performance and the old style can be repaired while the BA can't.

Well, the seller has a vested interest here and I'm more interested in an opinion from knowledgable individuals with no vested interest. I'm all for saving some money where the savings doesn't really cost too much in value and performance.

Comments?

We were just talking about the Hartzell Prop blades yesterday at the airport.

The 7666 is the old blade and there are two metal BA blades. 7497 is the newer more desirable BA blade. The 7496 was the first Hartzell metal BA blade used on RVs and has more RPM caution ranges than the 7497.

I cannot find the data but I remember there were reports that the Hartzell BA metal blade was 3 to 7 Knots faster on test airplanes. Someone that posts after should post the link. They say that the memory is the second thing to go and I cannot remember the first.

I also know that the fastest 360 parallel valve RV-6 that was raced used the 7666 blade that was re-twisted to help optimize it for RV speeds.

Prop

Nothing wrong with the F7666 blades . I would base the value of the prop by how much. "meat" is left on the blades . Take it to Mid Florida Propellor off Colonial Dr. and have them measure it if in doubt.
You can always look for some 7496 or 7497 blades to "upgrade " at a latter date .Tom

To B or not to B...

Hangar 1271 said:

I assume this is somewhere on the site but my search hasn't turned it up. I'm trying to shave something off the cost of an RV-8 without giving up too much performance and the prop, being a big ticket item, offers an opportunity. I have located a 10 year old, old style, zero time refurbished 72", B hub, Hartzel prop for about half what a new BA prop would cost. Not too surprisingly, the seller of the prop said, other than looks, minimal difference in performance and the old style can be repaired while the BA can't.

Well, the seller has a vested interest here and I'm more interested in an opinion from knowledgable individuals with no vested interest. I'm all for saving some money where the savings doesn't really cost too much in value and performance.

Comments?

Click to expand...

David,
Realize the first concern would be to check if your B hub is affected by the AD. Having owned a B hub on my Rocket, a B hub affected by the AD cannot be overhauled, only inspected or replaced. The BA blades will slightly outperform the standard blades as I found on my Rocket and many other RV owners who "converted".
Personally, if you want to save on a prop, avoid CS and go with a composite FP. Having built three RV's and flown over 3000 hours with them, my third RV is the lightest, simplest equipped of the three with a FP Catto prop. The lighter they are, the better they fly.

The 3 blade Catto Gen 3 will easily match the Hartzell in performance for a third of the cost and the maintenance....FYI

V/R
Smokey

Smokey,

You have no idea how many times I have gone over the fixed pitch vs constant speed question in my mind and with others. There are 50% more opinions than pilots on this issue. It is still an option but constant speed appears to be the more accept conclusion (doesn't make it the right one, just the more common decision) and that has been pushing me in that direction. I wish there was just one answer on this one.

How do you slow down with a fixed pitch prop? That is one of the problems the local RV drivers have with a fixed pitch.

Hangar 1271 said:

Smokey,

You have no idea how many times I have gone over the fixed pitch vs constant speed question in my mind and with others. There are 50% more opinions than pilots on this issue. It is still an option but constant speed appears to be the more accept conclusion (doesn't make it the right one, just the more common decision) and that has been pushing me in that direction. I wish there was just one answer on this one.

How do you slow down with a fixed pitch prop? That is one of the problems the local RV drivers have with a fixed pitch.

Click to expand...

Make sure your idle is set as low as possible. Plan ahead.... You can't enter downwind at 200 and expect to be at flap speed abeam the numbers. Back pressure with LOW RPM will slow you down...... This is not really a problem with a FP prop under normal flying conditions.

Unless you're flying a lot of close formation... slowing down with a FP prop is no big deal at all, like gasman said - plan ahead, low RPM and a little backpressure on the stick. I always slow down to about 120 MPH before entering the pattern anyway so slowing down to flap speed abeam the numbers is not an issue.

Now if you want to spend half as much money as a new CS prop, and still have a composite FP prop, you can always do what I did... buy the Sensenich Ground Adjustable prop. It's turbine smooth, very lightweight and the ability to tune the pitch on the ground to match your airframe, engine and flight mission is a very nice feature. They now have a version of this prop available for 360 engines, as well as the original 320 version.

IMHO, the biggest advantage of a CS prop on an RV is if you need the extra power of a full 2700 rpm takeoff from high altitude airports. There have been a couple times that I sure wished I had one on my -6. I also have about 70 hours in a buddy's hotrod RV-8 with 192hp IO-360 and Hartzell BA prop and the rush of acceleration when you push the throttle forward on takeoff sure is very addicting but my little 160hp RV-6 with the Sensenich GA prop does pretty well until I take it up into the mountains... then the takeoff performance reminds me a lot of the Cherokee 140 I owned and flew for 10 years... but at the top end, once wound up at cruising altitude my plane is almost as fast as that hotrod RV-8.

Light is Right...

Hangar 1271 said:

Smokey,

You have no idea how many times I have gone over the fixed pitch vs constant speed question in my mind and with others. There are 50% more opinions than pilots on this issue. It is still an option but constant speed appears to be the more accept conclusion (doesn't make it the right one, just the more common decision) and that has been pushing me in that direction. I wish there was just one answer on this one.

How do you slow down with a fixed pitch prop? That is one of the problems the local RV drivers have with a fixed pitch.

Click to expand...

David,
The Hartzell Blended Airfoil CS prop is a great propeller no doubt. The prop you are considering will perform 5% less efficient based on Les Dowd (Hartzell's chief engineer) calculations and my own personal experience with my HR2. As far as CS vs FP goes, having owned both, you will spend more money in the beginning and over the long run with a CS prop. Recently, I flew formation with my good friend DR (the purveyor of this site) alongside his 0-360 Hartzell BA RV6. My RVX has 180HP and a Catto Gen-3 Two-Blade and weighs 950# empty. Our takeoff distance, power settings, and cruise numbers were virtually identical.

I have flown every iteration of the RV8 engine and prop wise, including an IO-540 lead nosed monster. The best Eight ever was a frugally built 175HP 0-320/Catto 3 blade model I flew for a customer that weighed exactly 1000 pounds empty. The lighter they are, the better they fly...
The side benefit of a FP prop is a much better glide if you ever lost power for any reason. The CS issue most people don't want to address is engine failure contingencies. Having had an engine failure in several single engine airplanes (including the F16) glide capabilities are always present in my thought processes. My HR2 in SFO testing with the prop at flat pitch simulating Zero oil pressure was eye opening.

Weight, complexity and cost considerations notwithstanding, safe contingency planning with a FP prop is huge.

V/R
Smokey
www.iamanet.org

PS: From my RV4 builders manual 1989: "FP props save weight, cost and complexity". This still holds true today. Having flown quite a bit of formation and many summer visits to CO and the Idaho back-country mountains, and lived on a 1300' turf strip, FP prop RV's do very well, far in excess of any similar production airplanes. Realize when you talk to "RV drivers" they all have opinions and varied experience in type. Neal is correct that you need to have your engine idle set at 600-700 (I like 550) and be adept at slipping the aircraft gently on downwind and base to final to bleed off speed. Just a bit of prior planning and some hours under your belt and you won't have any problems. "The lighter they are, the better they fly"...

My customers experience is in unbolting a 7666 prop and bolting on the 7497 prop. No other changes RV6a with O-360-A1A and Electroair EI on one side. 5-7mph gain repeatable. Considering this is a new prop vs. a used prop, I would consider the value added for the extra $3k and probably go with the new. No matter that it's airworthy or not, any used part is a question mark unless you completely trust the overhaul shop and the seller.

I don't know of any B hub that is affected by the AD unless something has changed. The A hub is on the 6 cylinders and acro airplanes (RV6 is NAMED in that AD). The E hub and the non suffix hub is affected on the other.

Hartzell prop AD clarification

Reading this thread might cause a bit of confusion on which prop should have (ad's not mandatory on experimental) that eddy current inspection every 100 hours. I copied and pasted this off of Rocky Mountain Propeller's websight:

AD 2006-18-15 compliance -
applies to all Lycoming 360 series engines (except agricultural and aerobatic ? see AD 2001-23-08)

Propeller assemblies with Serial Numbers that DO NOT have a suffix at the end (?A? or ?B?)

Initially, an eddy current inspection must be done within 50 hours of the effective date of the AD (September 25, 2006)
then re-occurring each 100 hours there after. To eliminate this re-occurring inspection the prop should be overhauled with
a new ?B? suffix hub installed. New hubs are offered by Hartzell at a discounted price if the propeller is maintained in accordance
with Service Letter 61 ?Overhaul Periods and Service Life Limits for Hartzell Propellers?