7BCM propeller

[williamc]

I am installing a C85-12F with 0200 crank on my 7BCM project using Lasher STC SA232SO. The engine previously used a Mccauley 1A90 CF7148 on another plane. The STC requires a CF7144, CF7146 or CF7147 when using a metal prop. I'm seeking some advise on what prop to buy. Thanks guys.
Bill Chappell

[jepropst]

I have a C85-12 with the O-200 modification and the Lasher STC conversion. I've used a 7146 and it worked pretty well but could not get max rpm. I am currently using a 7144 and it works very well.
By the way, if you are using the Lasher STC your aircraft designation will technically be a "7AC-Conv".

[RRHaldeman]

I have a C85-12 (O-200) and I installed a Sensenich Model 74CK-2-46 and the combination seems perfect.

[williamc]

Thanks guys. Since this plane went to the army with a mccauley propeller, I think i'll stick with the mccauley. Sounds i'll be looking for a Mccauley 1A90 CF7144. Does anyone out there know of a good used one. A new one will probably make me think i've been robbed.
Bill Chappell

[jepropst]

For what it's worth and working from memory, I believe that the 7146 prop I have is a McCauley 1A90 that has round tips while the 7144 is a 1B90 which has square tips. I think that both models are still available from McCauley, but if I recall correctly, the square tip model is slightly cheaper.

[MikeB]

Also, if I remember correctly, my friend John has McCauley 70 x 42 on his L16/C85 with the rounded tips. While he says the climb is great the cruise is only around 85 mph and the rpm tends to run to the red line. This was the prop that came with the project when he bought it but he's thinking of having it repitched to 43 or 44 'bite' unless he can come up with a longer prop or better combination.
I believe the standard BCM props are limited to not less than 69.5 inches and not over 71 inches and static rpm specific according to type certificate.

MikeB

[sburke]

I have an L16A 7BCM with a C85-12 engine and a McCauley metal 1A90 CF7043 metal prop. The climb is over 600 ft per minute with a full fuel load and me. I am able to cruse at 85 mph at 2300 rpm. I think I have a climb prop here. According to the Univair catalog pg 13-2 for this aircraft the standard prop is a CM7144, CM7146 for cruise and CM7142 for climb. The STC for the 7BCM with the 1A90 shows;

"(7BCM only)
Static r.p.m. at maximum permissible throttle setting:
Not over 2450, not under 2350. No additional tolerance permitted.
Diameter: not over 71 in., not under 69.5 in."

My static rpm is 2420 with this CF7043 prop which now measures 69.75" . I am thinking of having it bent to near 45 to get better cruise performance since I live on the Pacific Coast.
Regards,

[williamc]

Thanks guys, for all the propeller comments. I just figured out how to post a picture so i'm posting my present ride featuring my wife on the nose. She gets a lot of photos at flyins. My present L-16A project will probably be named "MY BABE II".
Bill

[MikeB]

Nice looking, Bill (especially the grapic). I'm thinkin about putting our old squadron grapic from Kinross AFB, Michigan on my L16 door.
MikeB

[jnothpilot]

I am looking for a propeller also for a 7BCM L-16. I am using the C85 with 200 Crank. Any help in finding a Propeller, Nose bowl, and engine cowlings appreciated.

John

[MikeB]

There is a nose bowl and engine cowlings listed on Barnstormers. I've looked at the parts and they were in pretty good shape. I was going to buy the nose bowl (aluminum) but decided to repair mine instead. The cowlings would be for the short mount, though.

MikeB

[Doc]

Just to jump in here...My L-3B has the Don Swords (Don's Dream Machine) C-85-12F conversion with O-200 crank, rods, pistons and cylinders. I am swinging a McCauley 1B90-7140 with redline at 2650 RPM. Don's STC allows either the 1A90 or 1B90. I just spoke with Bill Pancake (THANKS!)...the 1A90 or 1B90 is approved for my 65 HP 7AC. As an aside, my 65 HP BC12-D ATC called for a 1A90 and it did not mention a 1B90...I needed a 337 to have that 1B90-7443 approved...easy... as McCauley thinks the 1A90 and 1B90 props are interchangeable, but the FAA needed approved data and accepted McCauley's data. Doc

[Dennis]

You might want to check out FAA Advisory Circular 23-27, subject: Parts and Material substitution for Vintage Aircraft.

Dennis