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turbofan
10-11-2018, 10:30 AM
66 Citabria with O320 requires a 2 inch spacer with McCauley prop per type specs...are the dowel pins required between the prop and spacer? I ask because the 74dm prop does not have the recessed holes to accommodate the dowel pins that attach the propeller to the spacer my question is are those pins required? Any info appreciated.

cubdriver2
10-11-2018, 01:19 PM
66 Citabria with O320 requires a 2 inch spacer with McCauley prop per type specs...are the dowel pins required between the prop and spacer? I ask because the 74dm prop does not have the recessed holes to accommodate the dowel pins that attach the propeller to the spacer my question is are those pins required? Any info appreciated.

You guys awake? I know what your thinking, Citabria guy? But he also has a J3 on 1320s, a Pa11 and a Pa18. Tom called me with this question and I didn't have an answer. I said " put it on .org and you'll have an answer in ten minutes "

Glenn

N86250
10-11-2018, 01:45 PM
The 1 1/2" spacer on the PA 12's O-235 here does not have dowels for the McCauley prop. That prop is drilled for bushings and the bushings are used. The 4" spacer on Roger's O-320-E2D on his 172M does have dowels for the McCAULEY IC160 CTM prop. That is all I know. I suggest a call to McCauley.

BC12D-4-85
10-11-2018, 02:01 PM
Look up the aircraft and engine here to find the approved McCauley propeller: https://mccauley.txtav.com/-/media/mccauley/files/mag.ashx

Then look up prop model to see if dowel pins A-2973-6 are required. My Citabria 74 and 80" required them and the spacer was pressed onto the prop's hub

Gary

skywagon8a
10-11-2018, 02:05 PM
66 Citabria with O320 requires a 2 inch spacer with McCauley prop per type specs...are the dowel pins required between the prop and spacer? I ask because the 74dm prop does not have the recessed holes to accommodate the dowel pins that attach the propeller to the spacer my question is are those pins required? Any info appreciated.
What model prop are you wanting to use and on what model 7---? Do you have the old Champ style (flat) nose bowl or the later more streamlined one? I was under the impression that the extended nose cowl started with the 1974 model year. IF I am correct your 1966 uses the prop without the spacer. For example if you are thinking of the model which on the Super cubs is called a "Borer" prop, that is a 1A175GM---- without the spacer. The same prop with the spacer is a 1A175GMA----. The A means "spacer" which is keyed to the propeller with a dowel pin. The spacer is considered to be part of the prop even though they can be separated.

hotrod180
10-11-2018, 02:20 PM
FWIW my old C150/150 used a 74DM6S5 prop, the S5 refered to a 1-1/4" spacer.
It was drilled to fit over the bushings on the crank flange, just like a prop,
and had two big pins that were an interference fit into the prop.
The (extra long) prop bolts went' through the whole works.
I have no idea why the spacered prop was required,
there didn't seem to be a clearance issue with the nosebowl or anything.
Here's pics of the spacer, front and back:

39263

39264

turbofan
10-11-2018, 02:32 PM
Thanks for the replies I called sensenich Manufacturing and they do have data to drill the dowel pins in my propeller mine is an older one which did not have the dowel pin recesses drilled so they will have to be drilled but again there is sensenich data to do it so it's a matter of shipping this thing off... another Prop Shop said the dowel pins are important to hold the propeller stationary against the spacer

Sent from my SM-G930V using SuperCub.Org mobile app (http://r.tapatalk.com/byo?rid=93960)

BC12D-4-85
10-11-2018, 02:57 PM
66 Citabria with O320 requires a 2 inch spacer with McCauley prop per type specs...are the dowel pins required between the prop and spacer? I ask because the 74dm prop does not have the recessed holes to accommodate the dowel pins that attach the propeller to the spacer my question is are those pins required? Any info appreciated.

McCauley or Sensenich...Ok now we find out you ref'd a McCauley's requirements but have the Semsenich DM prop. Here's their info regarding -S*- spacer and dowels:

http://www.sensenich.com/wp-content/uploads/2018/01/Application_Guides_Aluminum_Propeller_Applications _1349891787.pdf

Gary

turbofan
10-11-2018, 03:13 PM
The type specs require a spacer for either propeller I was just curious if the dowel pins were required but every Prop Shop I've talked to says they are

Sent from my SM-G930V using SuperCub.Org mobile app (http://r.tapatalk.com/byo?rid=93960)

BC12D-4-85
10-11-2018, 03:18 PM
Ok. Something's got to center and lock the prop to the crank flange besides the bolts through the spacer.

Gary

cubdriver2
10-11-2018, 03:21 PM
66 Citabria with O320 requires a 2 inch spacer with McCauley prop per type specs...are the dowel pins required between the prop and spacer? I ask because the 74dm prop does not have the recessed holes to accommodate the dowel pins that attach the propeller to the spacer my question is are those pins required? Any info appreciated.

McCauley or Sensenich...Ok now we find out you ref'd a McCauley's requirements but have the Semsenich DM prop. Here's their info regarding -S*- spacer and dowels:

http://www.sensenich.com/wp-content/uploads/2018/01/Application_Guides_Aluminum_Propeller_Applications _1349891787.pdf

Gary

Sorry Gary, I pumped him up as a J3 Pa11 Pa18 guy but he's still just a dopey tube driver the rest of the time :lol:

Glenn

BC12D-4-85
10-11-2018, 03:24 PM
All good and a fun review for me of that type of installation. I'd get a longer Mac and make that Airknocker perform before spending $ on a short Sen.

Gary

SuperClub
10-12-2018, 01:49 AM
Very interesting.. I just emailed Sensenich yesterday about this and got a quick reply. I have a nice Cub prop that may be used on a C150/150, and wanted to know how to get the dowel holes for the spacer. The current airscrews are drilled for the dowel pins as they are manufactured, but the old ones need to be drilled..
Don't know if it attached, but if you have a machine shop you trust, you can do it locally and you are good to go.39266

hotrod180
10-12-2018, 11:24 AM
66 Citabria with O320 requires a 2 inch spacer with McCauley prop per type specs...
you ref'd a McCauley's requirements but have the Semsenich DM prop. Here's their info regarding -S*- spacer and dowels:
http://www.sensenich.com/wp-content/uploads/2018/01/Application_Guides_Aluminum_Propeller_Applications _1349891787.pdf


Which model "Citabria" do you have?
Per that app chart, the 7GCAA, 7GCBC, 7KCAB, & 8KCAB use the S8 spacered prop,
but the 7GCA, 7GCB, 7GCBA, & 7KC do not.

hotrod180
10-12-2018, 11:32 AM
Very interesting.. I just emailed Sensenich yesterday about this and got a quick reply. I have a nice Cub prop that may be used on a C150/150, and wanted to know how to get the dowel holes for the spacer. The current airscrews are drilled for the dowel pins as they are manufactured, but the old ones need to be drilled..
Don't know if it attached, but if you have a machine shop you trust, you can do it locally and you are good to go.39266

I went through all this when I had my 150/150.
I
t all started when I wanted to have my existing prop repitched,
"and BTW please stamp it as an S5 for the spacer that's installed".
Turns out the spacer had been bootlegged on, prop shop sent the prop to the factory to verify that it was drilled per spec,
and the factory said no it wasn't and red-tagged it.
I was gonna buy a used 74DM6 from a friend, but it didn't have the dowel holes. for the spacer.
The local prop shop didn't drill holes, and didn't have a local machine shop they trusted to do it right.
I ended up buying a brand new 74DM6S5 prop from Art Mattson (of Cherokee fame),
and sold the old prop to a guy for his homebuilt after I knocked the spacer off.