Flottorp of Grand Rapids

[Brian Mahoney]

Hello, all. I am a newbie here!

We lived in lower Michigan from 1958-1963, and maybe it is in that timeframe that Dad picked up a wooden prop that seems to be in nice enough condition, built by 'FLOTTOP' of Grand Rapids. ("Both Blades Alike") It has 6 bolt bores of 7/16" in a 4 5/8" diameter circle, a center bore of >2 5/8", a thickness of just under 4", and overall diameter of 78 5/8"

We are wondering what it might have been installed on!

Stamped data:

1 8 7
DES. 78-61 (as best we can tell)
R. P. M. 2375
H. P. 120


If it is not super valuable as is, I am inclining toward a very light cleaning and finish reamalgamation, and possible cleaning and light buffing of the metal parts. Front faces of the metal tip protectors were either copper or copper plated, balance of edge protectors seem to be nickelplated steel.

The FLOTTORP decal on each blade seem intact under the darkened shellac or varnish.

[Dave]

Brian,
Flottorp made a model 78M61 that was used on a Phillips 1B or CT1, both using a Menasco C4 engine of 125 HP (their type certificate #754 covered both 120 and 125 hp engines, however and all pitches from 48" to 62") It looks like the 125 HP model used an 8 hole hub and the 120 hp used a 6 hole. There was also a model 78KR61 that was used on a Rearwin model 8125 and 8135 using a 120 HP Ken Royce engine. I suppose yours might apply to any of those, although if it has 6 holes I would say the Rearwin would be more likely.

Those are the only applications I could find.

Generally speaking, I don't think it's ever beneficial to try to fix up or restore a display propeller, unless it's already been ruined by someone doing that previously, in which case it really doesn't matter.

[Brian Mahoney]

Hi, Dave.

Just took another look with strong sidelight and good magnification... the initial number has two additional digits... possibly the seral number? it is 18729

The DES. number is very clearly 78-61. That is, it is very definitely a 'dash', not the letter 'M' separating 78 from 61. Am trying to get a clear macro shot of this while wrestling with a new digital camera. (Why can I never be on just ONE learning curve at a time? AASD = Adult Attention Surplus Disorder!)

-Brian

[Dave]

The 18729 is most likely a serial number and won't help much.

I've seen a lot of variation in the inclusion of letters within the drawing number. I don't think the type certificate requires it, and usually it just denotes the engine, in this case either the Menasco or Ken Royce.

Probably more relevant is whether it has 6 or 8 bolt holes in the hub.