Author Topic: beech roby prop  (Read 5866 times)

Tim Lunceford

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beech roby prop
« on: September 10, 2012, 12:07:01 PM »
Anyone currently using Beech Roby prop?   I have one in very good condition that I would like to trade for Aeromatic for Franklin powered Cadet.   Tim

Bill Poynter

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Re: beech roby prop
« Reply #1 on: September 11, 2012, 09:41:54 AM »
The installation of an Aeromatic on a Franklin 4AC-199 engine requires that the crankshaft be sawed off.  Getting FAA approval for that today would probably be pretty difficult.  If you could get approval for this mod, I don't know what the FAA would then think about going back to a wood prop on the sawed-off crankshaft.

Tim Lunceford

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Re: beech roby prop
« Reply #2 on: September 11, 2012, 11:42:35 AM »
Hi Bill,   My daughters Cadet has a stc for the Aeromatic.  The prop was damaged prior to our purchase and and we have flown it over a 100 hours with a Sensenich.  I was a bit leary of the cut-off hub and have kept a close eye on it.  So far know problems.  Thanks for the imput.  Tim

Dan C

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Re: beech roby prop
« Reply #3 on: September 18, 2012, 02:06:06 PM »
I thought I was done with Aeromatic propellers about 40 years ago. Now I have half a dozen of them. Some are on flying airplanes.....
Realize that production propellers came in #1,#2,#3 flange as well as #20 shaft sizes. The pre-war Franklin had it's own, unique flange that incorporated the "snout." These crankshafts were obsolete by the time Aeromatic was in production, after the war and I do not know of any Aeromatics produced for the prewar engines.
The snout does nothing more than center and stabilize a wood prop. Continental and Lycoming do without. You could have Kent Tarver provide the early bolt pattern on one of his unfinished hubs...after you cut the snout off. Or you could do what I did on my 6AC-298-F3, essentially a 6 cylinder version of the 90 hp, 4AC-199 series.....make an adaptor disc that bolts to the Franklin flange and is bored in the front to mount the Aeromatic. This combo has been flying my Bellanca T14-14 for quite a few years. It was never a certified aircraft, so it operates 'experimental/exhibition." Certification on the Cadet would be a big question mark.
Dan
   

ndeye

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Re: beech roby prop
« Reply #4 on: March 15, 2013, 10:28:42 AM »
Anyone currently using Beech Roby prop?   I have one in very good condition that I would like to trade for Aeromatic for Franklin powered Cadet.   Tim

ndeye

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Re: beech roby prop
« Reply #5 on: March 15, 2013, 10:30:29 AM »
Would you consider selling your beech roby prop?

Tim Lunceford

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Re: beech roby prop
« Reply #6 on: March 15, 2013, 06:44:39 PM »
I have sold the prop.  What engine are you running in case I find another Beech-Roby?   Tim

ndeye

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Re: beech roby prop
« Reply #7 on: March 16, 2013, 10:07:44 AM »
My Cuver Cadet LFA has a Franklin  4AC199-E3, 90hp with high compression pistons.