F-N-R Gearbox Variations

[Rex NZ]

Currently looking at setting up a classic silver century WSC with a FNR gearbox

I note there are several variations in the prop drive dogs on such FNR gearboxes

Here in NZ we saw virtually none of the post classic motors. As such I'm a bit lost as to which is which & what's best

Questions;
* Some prop drive dogs had the drive pin at the tip of the propshaft. What model was that?
* Some prop drive dogs had a floating drive pin at the base of the propshaft & a retainer at the tip. What model was that?
* Some prop drive dogs seem to be staked to the propshaft & a retainer at the tip. What model was that?
* which was the best or most practical setup?
* What's the story with the variations in the props? Some had a raised rim on the outer face, others were flat on the outer face

Help appreciated

Rex

[RickUK]

Hello Rex - I can only give you findings based on my own limited experience of the later motors.

The setup where it was all done at the propshaft tip was fitted to the 170 models if not others - eg. the Model 90.
The arrangement where the spring carrier sits on a shear pin and is secured at the propshaft tip is fitted to Kingfishers and I guess Ospreys

Question 3 - dont' know. Is this a repeat of Q2?

I don't think there would be a reason to prefer one setup over the other, though Seagull presumably had their own reasons in making the changes.

Props - the type which has a bit of a tapering exit (raised rim, and with two recesses to allow the boss securing pin to be driven in/out) are at least fitted to the Model 90 and the 170.
The flat outer face style of prop was fitted to Kingfishers. (also Ospreys?)

Although these two styles of prop (I am not aware of any other types fitted to FNR boxes) are different in hub profile, I believe they should be interchangeable as the distance from the inside hub bush to the external face is the same, although the appropriate spring carrier as above might need to be used. Rick

[Rex NZ]

RickUK

Thanks for the detail

Looks like I might have enough stuff to make at least 1x working setup

Thanks again
Rex