View Full Version : propeller choice?

07-11-2007, 06:24 AM
although a bit premature, I am starting to think of propeller choices for my stretched TriPace project..... Really want a constant speed but can't muster up enough for a 0-360 engine.....

Has anyone experience with constant speed (electric) props (MT, IVO etc) on a 0-320? Are these my only options.....

Any advice/ experience shared would be appreciated..


Steve Pierce
07-11-2007, 06:32 AM
The Tri-Pacer came from the factory with a constant speed as an option. The late Doug Beachel got a field approval for a constant speed on his o-320 powered Pacer.

07-11-2007, 06:54 AM
how might I find out the prop type etc?.... with a 0-320 on this Bushmaster a constant speed would be best while on floats...

I was under the misunderstanding that hydraulic CS props wouldn't work on a 150....



Steve Pierce
07-11-2007, 07:31 AM
This is from the Type Certificate Data Sheet. These are the conical mount engines. Let me know if you are going dynafocal. There is also a Lycoming Service Instruction for converting a fixed pitch engine to constant speed and vice versa.

O-320 Models Characteristics
O-320 Basic model - four cylinder, horizontally opposed air cooled, direct drive with automotive type generator and starter, provides for single acting controllable pitch propeller.
O-320-A1A Same as O-320, model designation change only.
O-320-B1A Same as O-320-A1A except for compression ratio, fuel grade and rating.
O-320-A1B, -B1B Same as O-320-A1A and -B1A respectively except have straight bore carburetor riser.
O-320-A2A, -A2B, and -B2A, -B2B Same as O-320-A1A, -A1B, -B1A and B1B respectively except have no provisions for controllable pitch propellers.
O-320-A2D Same as O-320-E3D except crankcase machined for conical instead of Dynafocal mounts.
O-320-A3A, -A3B, -B3A, and -B3B Same as O-320-A1A, -A1B, -B1A, and -B1B respectively except have provisions for 7/16" propeller attaching bolts.
O-320-A2C, -A3C Same as O-320-A2B and -A3B respectively, except for magnetos.
O-320-B2C, -B3C Same as O-320-B2B and -B3B respectively, except for magnetos.
O-320-B2D Same as O-320-D1D except conical engine mounts and no prop governor
O-320-B2E Similar to B2B except carburetor located same as O-320-D models
O-320-C2A, -C2B, -C3A, -C3B Same as O-320-B2A, -B2B, -B3A and B3B respectively, except have O-320-A series, low compression pistons, reduced ratings and lower grade fuel requirements.
O-320-C1A, -C1B, -C2C, -C3C Same as O-320-B1A, -B1B, -B2C, -B3C respectively, except have been converted to low compression pistons.

07-11-2007, 07:24 PM
Bart Miller was certifying the new Arctic Tern with an 80" Hartzell constant speed on a 160 0-320.Several older ac used 0-320 with c/s.Apache,Twin Comanche come to mind.

07-12-2007, 08:05 AM
Give the MT Prop folks a call. They make constant speed props that work and are LIGHT. The 80 inch Hartzell CS prop is for the O-360, and it's very heavy, due to the requirement to run a 10 pound harmonic damper.

Steve Johnson is running an MT (reversable no less) on his 180 Cub, maybe he'll chime in.


07-12-2007, 08:15 PM
Again with the MT prop push......why not just rename it to the MV prop and do all the marketing for them?

As one who has flown behind the heavy Hartzell since the early 80's on the Cub it does just fine, even with a few more pounds on the nose.

By the way it's not on a O-360, it's on a 0-320. There is no 10 lb damper installed.

After 2000+ hours of float flying with it and 20+ years, it'd held up well.

I'm curious how the MT / MV props hold up over that time span.

07-12-2007, 10:23 PM

Are you describing a Hartzell with the "compact" hub? As in a constant speed propeller?

You are correct, on the O-360, the 80 inch Hartzell requires a harmonic damper.

But, if you've got a Hartzell HC 2YK or R hub with no suffix, your prop hub is now subject to a recurrent AD, which requires eddy current inspection of your hub periodically. As in frequently.

Personally, I have run a Hartzell prop on MY airplane for well over ten years now, and this is the SECOND hub AD that has condemned my prop hub. I replaced the old one due to the corrosion AD. Now, mine (ten years old) is subject to eddy current inspections periodically. Great. Oh, and by the way, there is in fact, a history of these compact hubs disintegrating, in case you wondered why they issued an AD or two.

So, if you are running a Hartzell compact hub that is 20 years old, you really need to buy some lottery tickets. If you're lucky, either the prop will hold up, or you'll win the lottery.

But, whatever you do, don't get that 20 year old prop into a prop shop. Cause they'll condemn it in a heartbeat, due to Hartzell generated AD's.

So, let's see, why do I like MT props????

1) In my PERSONAL experience, they outperform both the Hartzell 76 inch and the Hartzell 80 inch constant speed propellers on takeoff and in climb. That is on more than one airplane, by the way.

2) The MT prop is almost 20 pounds lighter than the Hartzell 76 inch prop. Duh.

3) The MT prop is almost 30 pounds lighter than the Hartzell 80 inch prop with harmonic damper assy as installed on the O-360.

4) The MT prop is still more than 20 pounds lighter than a Hartzell 80 inch prop without the damper assy.

Seriously, if you have a Hartzell compact hub that is 20 years old, I guarantee you that if you take it to a prop shop, it will be subject to at least two AD's, and will likely be condemned as unairworthy. Under Part 91, you are never required to overhaul a constant speed prop, but there are in fact, some pretty good reasons to do so. Not the least of which is that some propeller manufacturers are making very short life components.

Ask me, I own a compact hub that is less than 12 years old, and it is subject to the latest AD. The one that this one replaced, was condemned as unairworth from the corrosion AD issued previously.

I'm through with Hartzell products, personally. If they can't build a prop hub that lasts for more than 12 years, I don't need their products.

Good luck with yours. I sort of blew off the AD's at first. Until I started talking to some folks at various prop shops, who have SEEN the results of ingnoring these AD's. Those guys certainly won't advise you that it's fine to ignore the condition of your Hartzell prop.

Call em MT or MV or whatever. I certainly didn't invent them, and was as skeptical as anyone before I flew them.

I'm a believer now, and I'll certainly never go back to a Hartzell compact series prop again.


bob turner
07-13-2007, 01:37 AM
The A/D has a progression that you can follow by watching the aerobatic versions: First, they mandate those frequent eddy current inspections, then they tell you to replace the sucker. The non-aero props are just five years behind the aero ones. And the old hubs cannot be used on anything. I lucked out and got a new hub for about $1200.

I generally don't "do" plastic, but I pay attention to MTV. When the time comes, I may graduate - too many red arcs on my RPM gauge.

07-13-2007, 08:51 AM

I had heard that reference the aerobatic props. One thing that a lot of folks don't seem to think about is that the MT props, and in fact, a lot of the "plastic" props out there nowadays are actually just a wood prop with a kevlar, or composite sheath and a metal leading edge.

The technology really isn't very new, since we've been using wood props for a few years now.


Dave Calkins
07-13-2007, 11:55 AM
Again with the MT prop push......why not just rename it to the MV prop and do all the marketing for them?

StalledOut, you know how as a kid you hated your little sister and always wanted to kick her, but if anyone else was mean to her you'd mess them up? You know?

Well, I think of MikeV. as my little sister. I don't want anyone else but me kickin' him. :D

..especially with your tone of voice


07-13-2007, 01:01 PM
Yeah Mike I am pretty lucky.

From winning things to never leaving money in a casino to the Hartzell never blowing apart. I'm the guy who walks in a casino, drops in a couple of bucks and hits for hundreds on the first pulls. There is a casino across from the airport at Green Bay that paid for the last Oskhosh trip just cause the plane was late. Hour delay, 2 minutes in the casino and I'd won more than the week had cost. That kind of stuff happens year after year for me. So yeah, people say I am lucky.............and now you're telling me I'm lucky the blades are still spinning. Guess I am.

All I know is the Hartzell has made it close to 30 years (it was on a PA-12in 79/80 then moved to the -18), and there is not a MT prop around that has that many years on it. You have a prop you've been behind for 25+ years Mike? Sounds like you change planes and props often.

He's all yours Dave, I'm done.

07-13-2007, 01:23 PM

Hey, you are absolutely correct on the life history of the MT props. They are new. Time will tell the story as to their durability, as you say, that has yet to be determined.

I'm not sure what Hartzell propeller you are referring to that's on your airplane. Perhaps it's not one with a compact hub. If so, I don't know anything about maintenance issues on it.

But, the AD for repetitive eddy current inspections on the older compact hubs is not optional, even under part 91. Compliance is mandatory, just like any AD. The previous corrosion AD was one that was done at overhaul, and it's what killed my last hub. Bought a 200 hour hub that was less than a year old, and it's now subject to the repetitive inspection.

Glad to hear you're lucky :P . I'm not that lucky, unfortunately.

Not sure what your point was reference me changing props/airplanes a lot. I bought my airplane with a well used Hartzell prop, whose hub got condemned at overhaul. Overhaul was required because the prop was blowing oil, grease, etc. Blades were near limits. New blades and a replacement hub about ten years ago, and that's the hub that I'm dealing with now.

I used to work airplanes for a living, however, and we ran several airplanes, and several different propellers on those airplanes.


Gee, thanks, I guess :roll: . Glad to hear you're feeling better, and are getting back into form--its been too easy around here for a while :angel: .


07-13-2007, 03:15 PM
Brian Sutton from MT propellers had constant speed MT prop for the o-320 at N.H. last year. I seen it !!!!

Steve Pierce
07-13-2007, 06:55 PM
You are very lucky if you have flown the same constant speed prop and haven't been hit by one of those expensive ADs. Had to replace a lot of them not because there was anything obviously wrong but because of mandated ADs or not cost effective to comply.

Those aerobatic boys have been putting the MT's through their paces for several years. Knew a Malibu that had the 2 blade Hartzell or McCauley replaced with a 4 blade MT and all his broken alternator, inter-cooler and turbo brackets went away.