OX5 Toothpick Prop

[MGretz]

I have an old toothpick style prop that has the OX5 bolt pattern.

Bolt Circle: 5-1/4" dia.
Hub Thickness: 4"
Hub Diameter (metal): 6"
Center Bore: 2.7"
Bolt Size: 3/8"

The prop is 98-1/2" long.

The only markings are as shown in the photo.

Can anyone shed some light on the make and model?
What does DES mean?

Mike Gretz

[MGretz]

When I got the prop about 20 years ago, I cleaned the brass because it was so black you could hardly see it. My intention at the time was to refinish the wood too. I realize now that might not be the thing to do.

[Dave]

"DES" refers to the design number, 650. The other number is probably a production number. I don't have that design number listed in any of my listings, but the general appearance is consistent with a post war use of an OX5 engine, possibly in the 20's or 30's.

Look at the bottom of this page for a very similar, DES 600, made by Fahlin. Yours may also have been made by Fahlin.

[MGretz]

Thanks Dave for the quick reply.

Using google, I had already seen that Fahlin prop. It does look very much like my prop - only shorter. I also noted on the web that Sensenich also used the DES designation on some of their props.

I'm going to take the prop back out into the sunlight and give it another close look to see if I can find any more markings.

Thanks again, and thank you for your great web site. Fills a real need. Other than your site, there is not much data available online about old props.

Mike

[Dave]

You'll see "DES" on a lot of manufacturers propellers, although it tends to be mostly on props built in or after the 20's. Prior to that "DWG", for "drawing" (or blueprint number) seemed to be more common.

Sensenich propellers "typically" will have the length in inches, followed by letters indicating the hub type, followed by the pitch in inches. So "72CK44" is a typical Sensenich model number indicating a 72 inch prop for a Continental engine and pitch of 44 inches.

I'm just guessing, but I think the most likely use of yours is listed here, if in fact it's made by Fahlin. Check the dimensions. I checked another source and found a "D 650" model Eagle Air (which I think bought the Fahlin type certificates) and it gives the length as 98" (pitch 51"), bolt holes 3/8", bolt circle diameter 5 1/4", hub diameter 7 1/4", hub thickness 4 1/8". It was used for a 125 HP engine, presumably a Kinner based on the other link to Fahlin models.

It may be that the hub dimensions are coincidentally the same as the OX5 engine and in fact yours was made for the Kinner instead.