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Prop selection for PA-18 150 A2B

D

daves123

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I currently have a 82-42 borer sea prop on my PA-18 150 and need to replace it with a 'land' prop due to ground clearance. I just put wheels on it and I don't have extended gear.

What is the recommended prop? I'm looking for a good compromise between climb and cruise. Is the Sensenich 74DM6-0-56 the 'stock' prop? I've done a bunch of searching and I'm having some trouble figuring out which one I need and where to find it. Used/reconditioned is fine.

Thanks,
Dave
 
82-42 is not just a sea plane prop. Most 150 wheel cubs in AK use the 41 or 42.
If you can get the 9 inch tip clearance (in level flight position) with your tire wheel combination you should be OK.

The Sensenich is what most cubs came from the factory with. It is a fair prop but all depends on what your mission will be. It will vibrate more but give better cruise, but not as good for takeoff and climb performance.

What tires you putting on?
 
The tires are 8.5x6 and I currently only have 7" of clearance, which is why my mechanic says the prop is not legal. My mission will be mixed so I need a good compromise prop. How does the Sensenich compare with the McCauley and which model of McCauley should I be looking at?
 
daves123 said:
I currently have a 82-42 borer sea prop on my PA-18 150 and need to replace it with a 'land' prop due to ground clearance. I just put wheels on it and I don't have extended gear.

What is the recommended prop? I'm looking for a good compromise between climb and cruise. Is the Sensenich 74DM6-0-56 the 'stock' prop? I've done a bunch of searching and I'm having some trouble figuring out which one I need and where to find it. Used/reconditioned is fine.

Thanks,
Dave
Click to expand...
I've got the "Stock Prop" and it ran/runs quite smooth (Maybe Pierce will chime in he used it as a test recently), the secret there is balance and proper pitch. "Stock" is definitely faster in cruise especially on small tires. For an extended climb (after getting off the ground and to best climb) I'd say it's about the same or maybe a little less based on cubs I have flown with but if you're not trying to get in and out of stupid places what you have would be better. With my Cub about finished in a full restoration and now being more fun directed I'm in your reverse search.
 
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Here's a thought..... Put the thrust line kit on. It should raise the prop the 2 inches needed.

I see lots of cubs on 8:50s with the borer props... Just need lots of air in them when you do the measuring.
 
There a STC for a McCauley 1A170/GM7452 ( STC held by McCauley so its free ) it has fatter blades than the Sensenich and it does pretty good i have one for the longer trip and i love it ,and still pretty good on take-off and not too bad on vibration and cruise at 110 mph at 2400 rpm.
 
I've got a similar set-up to yours: PA18-150, standard gear, 8:50s, and use the Sensinich 74-54 prop. It's a little more "climb" than "cruise," according to the Piper manual. 100 mph (or so) all day long, TOL not quite as short as with a Borer prop, but short enough for me in the Midwest.

Anne.
 
If you're going to use a 74" Sens., I second the 54 pitch. Its a good happy medium. I've always found the 56 to be a bit too much. Never flown a 52 so cant comment on that one. That prop tends to be something of a tuning fork, quite a bit of vibration. Maybe a good dynamic balance would fix that. I did that with my Borer and it made a good prop excellent, vibration wise.
Personally I like the Thrustline idea.
 
Not a cub, but 54 pitch was the sweet spot with the 74" Sensenich prop on my old C150/150TD.
 
Thanks for the input everyone. Looks like the 74-54 is the best option if I go for a new prop. I'll also check into the thrust line kit and extended gear. What's the rough cost for the extended gear?
 
I have a 0320A2B on my PA-18-150. I have a choice of a 82-42 borer prop or the 74DM6-52. I stayed with the 74DM6-52 as I can operate on relatively short strips and get good cruise with it. This is with 29in Bushwheels. 105-107mph in cruise at 2400rpm and 8.5gph. Not much vibration either.
 
The Sensenich 74DM6-0-52 prop will turn about 2500 rpm static on a 150 hp engine, which is beyond the limitation in the TCDS (unless operated as a glider or banner tow). If your mechanic won't live with the Borer prop sitting on 8.50 x 6 tyres he also will most likely not accept a static rpm beyond the TCDS so a coarser prop than the 52" would be in order.

FWIW I have flown the same Cub with the 52" pitch Sensenich prop and the 43" or 44" pitch (can't remember which now) Borer prop and there wasn't much difference in performance, including cruise speed. In fact for a given manifold pressure the plane went faster with the Borer prop!

Andrew.
 
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