Prop for M-6-235

Andy Young · Post by **Andy Young** » Fri Mar 24, 2017 4:12 pm

With all the talk of props for different model, engine, and landing gear combinations, I've sort of lost track: which is the preferred McCauley prop model and length for an M-6-235 with stock length gear? I run 31" Bushwheels all summer, but 8.50s all winter, and don't want to have to swap props when I swap tires.

Anybody have a good used prop of the appropriate model that they want to sell?

Thanks

DirtDobber · Post by **DirtDobber** » Fri Mar 24, 2017 7:02 pm

If you want a 3 blade Mac, I know where one is that was removed from an M7 recently. Good shape.

Otherwise an 86" two blade will be the best performer.

chazdevil · Post by **chazdevil** » Fri Mar 24, 2017 7:40 pm

Yup, if you go to the 26" GY in lieu of 8.5, you can run the 86" Mac on stock gear. . I really like mine.

Andy Young · Post by **Andy Young** » Sat Mar 25, 2017 9:58 am

Thanks guys. Don't think I can go 86", as I might have it on skis next winter. So am I looking for 82"? 84"? Which model? What's the paperwork basis?

Andy Young · Post by **Andy Young** » Sat Mar 25, 2017 10:00 am

DirtDobber wrote:If you want a 3 blade Mac, I know where one is that was removed from an M7 recently. Good shape.

Otherwise an 86" two blade will be the best performer.

I think I'd prefer the two-blade, but I am curious about the price on the three-blade.

gbarrier · Post by **gbarrier** » Sat Mar 25, 2017 10:45 am

It's amazing how much difference props make. I have a three blade scimiitar Hartzell on my M6-235. I also fly a M7-260 with a three blade Mac. I find myself pulling about 20" in the pattern with the Mac to do the same thing that I do on the Hartzell at 15" . I think I would like to have a nice MT 3 blade to put the old girl on a diet and move the cg a little aft but after seeing the difference between those two props no way without flying one first.

Apologies to Andy for hijacking your thread. Sometimes just like to babble.

Andy Young · Post by **Andy Young** » Sat Mar 25, 2017 1:00 pm

Ok, I got a little less lazy and looked through the archive. Looks like I shoild be looking at the 81" 90RA-9, or, if I add extended gear (which I am considering) the 86" 90RA-4. Looks like these both might be on the type certificate?

Anyone know of a used one of either of these for sale?

It does seem like the two blade is a better fit for my mission than the three blade. Like to avoid adding weight to the nose.

DirtDobber · Post by **DirtDobber** » Sat Mar 25, 2017 1:38 pm

If you really want to get weight off the nose, have the ground clearance, and get max performance all around....83" 2 blade MT. 15-20 lbs lighter and will rip better than the 86" Mac (or any of the others mentioned).

Andy Young · Post by **Andy Young** » Sat Mar 25, 2017 2:12 pm

DirtDobber wrote:If you really want to get weight off the nose, have the ground clearance, and get max performance all around....83" 2 blade MT. 15-20 lbs lighter and will rip better than the 86" Mac (or any of the others mentioned).

All true, though I'm not fond of the price of the MT, nor the servicing logistics.

MauleWacko · Post by **MauleWacko** » Sun Mar 26, 2017 7:27 am

Andy Young · Post by **Andy Young** » Sun Mar 26, 2017 7:39 am

MauleWacko wrote:The full model # for the McCauley is a B2D37C224/90RA the -4 number equals blade length from 90 inches which is 86 inches or a -8 for 82 inches. It is on the T.C.. I needed one years back and had a hell of a time finding one or even blades. This is one of the things I mention about (one off model numbers on this type aircraft). The C224 was not used on anything else and it is very hard to find a straight one. Don't pass one up, they are not laying all over the place used.

Thanks; that's exactly the info I was looking for. Now to find one. I might have to pony up and buy new, but I'm sure the price will be shocking.

freedom · Post by **freedom** » Sun Mar 26, 2017 11:36 am

@ gbarrier, what's the 3 blade hartzell model you are using?

gbarrier · Post by **gbarrier** » Sun Mar 26, 2017 5:17 pm

Freedom, it is a model HC-C3YR-1RF. I really like the prop and feel like it pulls well. It's just heavy. Don't have a copy of wt. and bal. here at the house but I want to say that it is something like 22# heavier than the original two blade one. Prop has less than 300 hours on it and represents quite an investment so guess I'll keep it.

maules.com · Post by **maules.com** » Mon Mar 27, 2017 4:43 pm

The 86" McCauley two blade needs larger than 8.50x6 tyres, and also is only certified on the O540 J, or IO540 W, engines which run at 2400 rpm max.
The 80" three blade Mac is heavier than the 81" and 86" two blade Macs and lighter and longer than the three blade Hartzell.
Using same day, same airplane, same pilot during STC testing qualification flights, the 80" three blade was much quicker than the 81" and and a tad quicker than 86" two blades in initial acceleration to aprox vx. then the 80" three blade, and 86" two bladed climbed at very similar fpm and better than the 81" two blade.
The 86"two blades are a tad faster in cruise.
The 80" three blade is significantly quieter and smoother than either of the two bladed. The three bladed costs a bit over a thou more. The Mac's have no service time requirements.

Andy Young · Post by **Andy Young** » Fri Apr 14, 2017 4:05 pm

So....
Any of you folks know of a good used McCauley 224 for sale?

Prop for M-6-235

Prop for M-6-235

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