Hartzell Props for E Series - Identifying & General Info
Posted: Wed Oct 30, 2019 2:11 am
Okay sports fans, I've had some folks reach out to me directly, so I'm going to do one exhaustive post on props on E series Navions and put the references all in one place, then this dog is dead. If you missed Shane Rogers' video in the IV Navion Club Facebook group on this subject, go watch it -- his point, which is basically "if you're going to buy an E series Navion, it better have an MV prop" is the best advice any of us who fool with these things can give. But if you want to know more about the documentation and specifics that support this argument, or if you own one of these airplanes already and need information, here it all is.
Take a look at your prop model number. This can be found stamped into the prop hub and also in your prop logbooks. You are first concerned with the first three letters/numbers, which should be HC-1, HC-8, HC-A, or HC-D. The HC stands for "Hartzell Controllable" and the number or letter after the dash identifies the basic design. Let's look at those individually:
HC-1: This is the "original" Navion prop. It is a "bladder" or diaphragm-style propeller, and that bladder needs to be replaced every two years. It may or may not have a governor. If it has a governor, it will behave like a constant-speed prop. If it doesn't, it is merely a "variable pitch" prop (if you are unfamiliar with the difference, contact me and I will explain). According to Hartzell, the first cabin-controllable propeller they ever built was for the Navion, and this is it. This means that the HC-1 is by definition the oldest hub and blades you're going to find in service. I've looked at a lot of airplanes, and the serial numbers I see on HC-1s typically date from the early 1950s. Awfully old for a propeller! This prop is subject to a 5 year, 250-hour (whichever comes first) recurring inspection mandated by AD 97-18-02R1. You can find the AD here:
http://hartzellprop.com/wp-content/uplo ... 8-02r1.pdf
Additionally, per Hartzell Service Bulletin 61-331, issued in 2012, the HC-1 propeller is no longer supported (i.e., you can't get parts), and should be REMOVED FROM SERVICE at the next teardown, due to safety concerns. You can find that service bulletin here:
http://hartzellprop.com/wp-content/uplo ... -R01-W.pdf
Because of this service bulletin, few prop shops will touch an HC-1 propeller, due to liability concerns, and they are becoming fewer by the minute. I personally agree with their point of view. If you owned a prop shop, would you certify a 60+ year old propeller as airworthy, that the manufacturer has explicitly said "remove this from service"? I wouldn't. With an HC-1, a prop shop can't say "All SBs complied with", because if they were, the hub would be in the trash can. You CAN convert an HC-1 to an HC-D by replacing the hub and bearings, assuming your blades and clamps are good, which would at least get you to a supportable, serviceable propeller (with a 5 year/500 hour AD), but the parts alone for doing this run $9,355.50, as of August 2019. You could also technically reuse your current blades (if they're good), have them modified to the new "MV" shank, and buy all the rest of the parts to stick them in an AD-free "MV" propeller, but the cost of this would far exceed buying an "MV" prop on the used market -- and who wants to spend all of this money on a prop with 60+ year old blades in it?
*Bottom line: If you're looking at an airplane with an HC-1 prop on it, you really need to budget for a $15k used prop at the next AD inspection. If you've got an airplane with an HC-1 on it now, start saving up for a replacement, or make up your mind to do an engine conversion when the time comes. I'd be suspicious of any shop willing to do the AD on an HC-1 -- and eventually, you're not going to find a shop willing to certify it. Furthermore, if your prop goes in for AD inspection and needs a bearing, etc., they are no longer made! Boat anchor.
HC-8. This almost doesn't warrant discussing, but there was a Navion for sale on Barnstormers recently that had an HC-8 propeller on it, so there are bound to be more. I looked at and considered this airplane personally, and this unusual model number prompted me to do some research. The HC-8 is an early version of an HC-A, which we'll discuss later. It is a constant-speed, piston or "dome" style propeller with an oil transfer unit ("collar") and mandatory governor. The HC-8 will fit on the airplane and fly. However, the STC which allows for the installation of this style constant speed prop on the Navion, STC SA1-635, specifically does NOT include the HC-8 model. Bottom line: The HC-8 is not a legal installation on a Navion. You need a prop.
HC-D. This is the current-production, currently supported successor to the HC-1. Like the HC-1, it is a "bladder" or diaphragm prop, which also needs its diaphragm replaced every two years. And, like the HC-1, it may or may not have a governor. If your prop number begins with HC-D2(X or V), you are subject to a 5 year, 500-hour recurring inspection per AD 97-18-02R1 (referenced above), but your prop is still supported. However, if your prop number begins with HC-D2MV (Note the *MV*), you are AD-free. This is ONE of the TWO propellers which can be referred to as the "MV" prop. A new one of these from Hartzell runs about $35,000.
HC-A. This is the current-production, constant-speed, piston or "dome" style propeller with an oil transfer unit ("collar") and mandatory governor. If your prop number begins with HC-A2(X or V), you are subject to a 5 year, 500-hour recurring inspection per the same AD. However, if your prop number begins with HC-A2MV (Note the *MV*), you are AD-free. This is the other of the two propellers which can be referred to as the "MV" prop. A new one of these with oil transfer unit from Hartzell runs about $42,000.
If you have an HC-A or HC-D prop that is subject to the AD, which means model numbers HC-(A or D)2(X or V), that's not the end of the world, as your prop is still supported, and a number of shops will still inspect and certify them. However, as Shane said, the number of shops willing to do the AD, even on an HC-A or HC-D, is steadily decreasing. You are fine for now, but you need to also be thinking down the road. Do you want to stay E series, or convert to something else? Put some money back, either way. My local prop shop (South Coast Propeller in Alabama) charged $1700 for the AD inspection on an HC-A2V last year -- but that price assumes the prop needs nothing. Your mileage may vary. But how long will they continue to do the inspection?
If you have an HC-(A or D)2(X or V), you can have it converted to "MV" specification and eliminate the AD entirely, but there are several expensive parts involved -- namely the blade clamps. I'd budget 10 grand for the conversion, and your blades had better be good. In my experience, you can do the AD inspection several times over for the cost of the conversion, but as shops willing to do the AD inspection go away, the conversion may become something to seriously look at.
Finally, some prop shops will not do just the AD inspection, and will instead demand that the prop be completely overhauled, which costs more. Expect 5 grand in that case, IF your blades still have the thickness and margin to be reground.
Factor all of this into consideration when looking at an E series airplane. I like the E series and plan to keep mine. It goes without saying that an HC-D2MV or HC-A2MV is the airplane to buy. If I was looking at one with an HC-1, I'd factor either replacing the prop (~$15k used) or doing an engine conversion the next time the AD is due. If I were looking at one with an HC-(A or D)2(X or V), I'd be a little more comfortable, if there is good time remaining until the next AD inspection -- but beware, it's not getting any easier.
The nanual for the HC-1 or HC-D "Diaphragm" or "bladder" props is here: https://hartzellprop.com/wp-content/upl ... R03-AW.pdf
The manual for the HC-A "Dome" prop is here: https://hartzellprop.com/wp-content/upl ... R04-AW.pdf
Hope this helps someone with these recurring questions!
Take a look at your prop model number. This can be found stamped into the prop hub and also in your prop logbooks. You are first concerned with the first three letters/numbers, which should be HC-1, HC-8, HC-A, or HC-D. The HC stands for "Hartzell Controllable" and the number or letter after the dash identifies the basic design. Let's look at those individually:
HC-1: This is the "original" Navion prop. It is a "bladder" or diaphragm-style propeller, and that bladder needs to be replaced every two years. It may or may not have a governor. If it has a governor, it will behave like a constant-speed prop. If it doesn't, it is merely a "variable pitch" prop (if you are unfamiliar with the difference, contact me and I will explain). According to Hartzell, the first cabin-controllable propeller they ever built was for the Navion, and this is it. This means that the HC-1 is by definition the oldest hub and blades you're going to find in service. I've looked at a lot of airplanes, and the serial numbers I see on HC-1s typically date from the early 1950s. Awfully old for a propeller! This prop is subject to a 5 year, 250-hour (whichever comes first) recurring inspection mandated by AD 97-18-02R1. You can find the AD here:
http://hartzellprop.com/wp-content/uplo ... 8-02r1.pdf
Additionally, per Hartzell Service Bulletin 61-331, issued in 2012, the HC-1 propeller is no longer supported (i.e., you can't get parts), and should be REMOVED FROM SERVICE at the next teardown, due to safety concerns. You can find that service bulletin here:
http://hartzellprop.com/wp-content/uplo ... -R01-W.pdf
Because of this service bulletin, few prop shops will touch an HC-1 propeller, due to liability concerns, and they are becoming fewer by the minute. I personally agree with their point of view. If you owned a prop shop, would you certify a 60+ year old propeller as airworthy, that the manufacturer has explicitly said "remove this from service"? I wouldn't. With an HC-1, a prop shop can't say "All SBs complied with", because if they were, the hub would be in the trash can. You CAN convert an HC-1 to an HC-D by replacing the hub and bearings, assuming your blades and clamps are good, which would at least get you to a supportable, serviceable propeller (with a 5 year/500 hour AD), but the parts alone for doing this run $9,355.50, as of August 2019. You could also technically reuse your current blades (if they're good), have them modified to the new "MV" shank, and buy all the rest of the parts to stick them in an AD-free "MV" propeller, but the cost of this would far exceed buying an "MV" prop on the used market -- and who wants to spend all of this money on a prop with 60+ year old blades in it?
*Bottom line: If you're looking at an airplane with an HC-1 prop on it, you really need to budget for a $15k used prop at the next AD inspection. If you've got an airplane with an HC-1 on it now, start saving up for a replacement, or make up your mind to do an engine conversion when the time comes. I'd be suspicious of any shop willing to do the AD on an HC-1 -- and eventually, you're not going to find a shop willing to certify it. Furthermore, if your prop goes in for AD inspection and needs a bearing, etc., they are no longer made! Boat anchor.
HC-8. This almost doesn't warrant discussing, but there was a Navion for sale on Barnstormers recently that had an HC-8 propeller on it, so there are bound to be more. I looked at and considered this airplane personally, and this unusual model number prompted me to do some research. The HC-8 is an early version of an HC-A, which we'll discuss later. It is a constant-speed, piston or "dome" style propeller with an oil transfer unit ("collar") and mandatory governor. The HC-8 will fit on the airplane and fly. However, the STC which allows for the installation of this style constant speed prop on the Navion, STC SA1-635, specifically does NOT include the HC-8 model. Bottom line: The HC-8 is not a legal installation on a Navion. You need a prop.
HC-D. This is the current-production, currently supported successor to the HC-1. Like the HC-1, it is a "bladder" or diaphragm prop, which also needs its diaphragm replaced every two years. And, like the HC-1, it may or may not have a governor. If your prop number begins with HC-D2(X or V), you are subject to a 5 year, 500-hour recurring inspection per AD 97-18-02R1 (referenced above), but your prop is still supported. However, if your prop number begins with HC-D2MV (Note the *MV*), you are AD-free. This is ONE of the TWO propellers which can be referred to as the "MV" prop. A new one of these from Hartzell runs about $35,000.
HC-A. This is the current-production, constant-speed, piston or "dome" style propeller with an oil transfer unit ("collar") and mandatory governor. If your prop number begins with HC-A2(X or V), you are subject to a 5 year, 500-hour recurring inspection per the same AD. However, if your prop number begins with HC-A2MV (Note the *MV*), you are AD-free. This is the other of the two propellers which can be referred to as the "MV" prop. A new one of these with oil transfer unit from Hartzell runs about $42,000.
If you have an HC-A or HC-D prop that is subject to the AD, which means model numbers HC-(A or D)2(X or V), that's not the end of the world, as your prop is still supported, and a number of shops will still inspect and certify them. However, as Shane said, the number of shops willing to do the AD, even on an HC-A or HC-D, is steadily decreasing. You are fine for now, but you need to also be thinking down the road. Do you want to stay E series, or convert to something else? Put some money back, either way. My local prop shop (South Coast Propeller in Alabama) charged $1700 for the AD inspection on an HC-A2V last year -- but that price assumes the prop needs nothing. Your mileage may vary. But how long will they continue to do the inspection?
If you have an HC-(A or D)2(X or V), you can have it converted to "MV" specification and eliminate the AD entirely, but there are several expensive parts involved -- namely the blade clamps. I'd budget 10 grand for the conversion, and your blades had better be good. In my experience, you can do the AD inspection several times over for the cost of the conversion, but as shops willing to do the AD inspection go away, the conversion may become something to seriously look at.
Finally, some prop shops will not do just the AD inspection, and will instead demand that the prop be completely overhauled, which costs more. Expect 5 grand in that case, IF your blades still have the thickness and margin to be reground.
Factor all of this into consideration when looking at an E series airplane. I like the E series and plan to keep mine. It goes without saying that an HC-D2MV or HC-A2MV is the airplane to buy. If I was looking at one with an HC-1, I'd factor either replacing the prop (~$15k used) or doing an engine conversion the next time the AD is due. If I were looking at one with an HC-(A or D)2(X or V), I'd be a little more comfortable, if there is good time remaining until the next AD inspection -- but beware, it's not getting any easier.
The nanual for the HC-1 or HC-D "Diaphragm" or "bladder" props is here: https://hartzellprop.com/wp-content/upl ... R03-AW.pdf
The manual for the HC-A "Dome" prop is here: https://hartzellprop.com/wp-content/upl ... R04-AW.pdf
Hope this helps someone with these recurring questions!