The International Cessna^® 170 Association

Folks, recently for reasons I won't discuss, I've been doing some research on spinners. I know there are 170s with a 0-300-C, D or E which has an ARP 502 Type I flange (standard 6 bolt flange crank) that have a skull cap type dome spinner installed.

The 6" is used on the C-145-2/0300-A,B and it's diameter covers the 5.25" diameter bolt circle with 3/8" bolts of the SAE #3 flange and is not to large for the prop hub used with than flange.
The 5" is used on the SAE #1 flange found on the smaller Continental 4 cylinders which has a 4.375 bolt circle diameter with 3/8" bolts. It just fits around and is held snuggly in place by the bolt heads and is not to large for the prop hubs on props used.

The ARP 502 Type I flange has a 4" bolt circle diameter with 1/2" bolts. The circle diameter is smaller but the bolt heads are larger. It is clear the 6" spinner will cover it but will likely be loose about the bolt heads and may be to large for the prop hub. The 5" will likely be a better fit but may not fit over the larger bolt heads and I'm pretty sure it will not be to large for the prop hub.

I'm not interested in legalities. Our Associations engine STCs are silent on the issue.

I want to know what skull cap dome spinner has actually been used. The 5" diameter or the 6" diameter?

Bruce,

Are you just looking for what has been used on 0-300-C, D or Es,or any 170?

I have a 6" installed on my O-300A.

Fearless Tower wrote:Bruce,

Are you just looking for what has been used on 0-300-C, D or Es,or any 170?

I have a 6" installed on my O-300A.

Yes essentially I'm only looking to find what size skull cap simmer has been used on an model 170 that has a stock 0-300-C,D or E installed.

I know a guy with an o300-D and a skull cap spinner. I'll be at the airport this weekend and will measure mine...I mean the guy with the illegal spinner

bagarre wrote:I know a guy with an o300-D and a skull cap spinner. I'll be at the airport this weekend and will measure mine...I mean the guy with the illegal spinner

Thanks, that would be great. If it's a 5", how tight if at all is it around the prop bolt heads. If it is a 6" how close to does the edge of the spinner come to edges of the prop hub.

Pictures sent to me via email would be great with the spinner on showing the relationship of it and the prop hub and if not to much trouble just the prop hub with the hold down bracket installed on the prop.

And no one said anything about illegal because we're not discussing that remember.

Thanks David.

Maxwell Aircraft Service, in Crystal, MN, converted a McCauley DM7652, off of a Stinson, to an MDM7649 seaplane prop for my 170B. It came with the Stinson spinner, so was installed with the prop. So many questioned the spinner that we replaced it with one from Wag-Aero. It sure looked good. The only picture I can find is in, Vintage Airplane, May 1998, page 19. If anyone says it's okay, it may have to go back on. -Bill

Thanks Arash, that is the info we are looking for. Any others using a skull cap on a 0300-C, D or E with the stock crankshaft?