What model is this?

[Keith.P]

Why didn't I think of the SJM, also the LM was a four blade prop.
I would appreciate a picture John, as I have never seen a small four blade.
Fins on the head, did it need them?
The early Anzani pilot had a flat fin-less head, and went on to a basic finned head later.
Seagull needed to put pictures out for new and upcoming models, so they could sell them, not have a thousand motors on the shelves and then advertise, as I said before, the motor sold was not always the motor advertised.
Two odd things, no lump on the side of the barrel that would have been for the tell-tail, unless it's on the other side and that head is very thin and with just two bolts it would be prone to problems.
An artist picture or a photo, what ever it is, it's interesting anyway.

[Charles uk]

We call them cooling fins, but could they also be called stiffening ribs?

It would make the tooling more expensive but the end result weight less.

[headdownarseup]

Interesting you mention stiffening ribs Charles. What needs stiffening in the cylinder head? I can see why you've asked this question as i've also pondered whether or not the fins do actually provide any strength/stiffness or if they do indeed provide a little bit of cooling.
If this were an FV or similar that we were talking about with those delicate half round cast tank mounts incorporated into the head, well that would be a different story, but what we're talking about here is a later square block cylinder head with quite beefy looking and flat mounted tank supports. Apart from lifting an outboard motor by its fuel tank whilst recovering or fitting the engine to the transom, the ideal point of balance for carrying one of these motors is by the drive tube, or heaven forbid one of those tacky looking carry handles that go around the drive tube that Keith hates so much.
4 bolts are obviously better than 2 when it comes to attaching a cylinder head onto a cylinder. Does that in itself make the head any stiffer or weaker? As keith has mentioned, a 2 bolt head was probably very prone to premature failure if that was ever the case.
The engine will of course go through a heat cycle at every use, and some of this residual heat ends up in the fuel tank via the cylinder head. A strange thing when you consider we're trying to keep heat away from fuel for obvious reasons despite the engine having an isolation pad between the tank and head. Would there be any more heat build up if there wasn't any fins on the head to begin with? (a bit like an early anzani pilot engine Keith) A seagull is a watercooled design after all is said and done.

I'm not sure that i would agree that what was advertised was EXACTLY what you ended up with. From what i've seen in many old seagull adverts there's a lot of mention about extensive testing that's already been done before a new engine is put out in general circulation. I can't imagine that British Seagull would allow themselves to be wide open to some discriminating letters from angry users saying their outboard motor has failed prematurely because of a small design fault. Development of any new design can take many different forms, and from what we've seen in the previous images this could easily be one such occasion where a few sneaky pictures of an "experimental" engine have made their way into a publication. Whether or not this was intended remains to be seen, but i remember Charles P saying something to the effect that he has letters from customers saying as much. This is not the sort of thing that anybody would want to be publicly known, but i'm fairly sure this kind of thing did happen and BS learned very quickly from it. There has been mention in the past with 1 piston ring fitted to pistons. Was this a sneaky way of BS trying to reduce their production costs somehow? Probably, but it didn't work very well did it, and so BS learned not to mess with something that worked well enough in its first instance.(not broken and didn't need fixing from a design point of view)

Remember that if these images are indeed genuine, then any motor in the line up prior to this would be slightly different as BS have just moved away from one design with the "little 40" etc. with a through bolt fixing, to a newer "sealed" water jacket. Late model LS and this new "experimental" are both presumably 64cc, so there's little change in cylinder specs apart from the water jacket at one end of the cylinder. Cylinder head design between the 2 motor types probably would vary a little bit, but not so that you'd notice from the exterior apart from earlier heads being non scripted and later heads having "DONT REMOVE". A late model LS by the looks of it has the same overall cylinder head design as this "experimental" 40. Does the cylinder head in any square block engine need to be strengthened/stiffened? Why do all of the other motors in the "little 40" range also have fins on their cylinder heads? I don't think this is a matter of strength or stiffening as such as there's plenty of older square block engines still running perfectly well today, same with many older SJM/P motors. It's just a design feature that stuck with the rest of the square block models. True, the physical size of some of these fins vary a little bit, perhaps for better cooling as i've suggested, but i wouldn't say it was for extra strength.
That wasn't broken so BS never needed to fix it. What DID need fixing was the earlier crankcases in the FV's with their newly introduced (re-designed) webbed part above the tiller. When you think about it, the fixed tiller provides a good handle to lift the motor by, and over time the crankcases broke as a result of these stresses placed upon it. Later on the tiller went to a tilting method which carries on in all the other motors both big and small.
Case in point with the "air cooled" little model 40 at the start of this thread i was interested in. I think this is all down to development and extensive testing on BS's part. Some design changes work very well, and some things don't.

Props are another design change.
3 blades or 4. We're all used to seeing a 3 bladed prop on an FV, but let's not forget that many of these little engines were only 55cc.
With a slightly larger displacement of 64cc as in the SJM/P etc. perhaps it was thought that a larger engine produced a bit more power (read into that what you will) but again i think this is all down to development and if you like improving on an older design. Maybe 4 blades on the prop was thought to produce a bit more thrust for better efficiency as there's a bit more power from the engine to spin it in the first place. Who knows for sure, but i think it's still down to development rather than change for change's sake.

Here's what you want to see with props.
It's not the best FV prop you've ever seen, and in truth its a bit battered but you get the general idea with these smaller props.
Enjoy

[Keith.P]

Pictures much appreciated John, Did Seagull have problems with new motors, Yes, just look at the changes that were made to the little forty in its short life, otherwise it would have stayed the same until the end of production, a lot of Jeremy's work shows that.
At my age Charles I call them fins, at your age all you can think about are stiffeners.
Would seagull advertise a motor not the same as the one they ended up selling?
Point in question, the Little Forty.

british seagull 40 p3a.jpg

Just look at that gearbox and water pump housing, its not an artists impression, its what they advertised for sale.
Plus that's a two blade prop, like a small bow tie.

[Charles uk]

Did they ever manufacture that waterpump housing or that propellor & lower unit, young man?

[headdownarseup]

I would tend to agree (mostly) Keith.
Here's a thing though, we've heard many times before of how British Seagull stated that their outboard was "the best in the world", or "the best that money can buy" etc. That's a pretty bold statement to make without first having carried out plenty of testing before they introduced a new engine. Testing and development is where it's at, and yes, the pictures you've shown would rather imply that there may well have been a slight "change" to the specs before BS settled on what was to become the norm.
To arrive at the point where you could claim that your outboard was indeed the "best in the world" takes a lot of experimenting with to get things right. Sometimes BS got it right straight away, and others not quite right but with room for improvement. We could argue that the "little 40" was one such venture that needed a lot of "tweaking" to get it absolutely right. With the SJM/P engines i think BS understood what had gone wrong before (if you can call it that) and any further developed motor was constantly improved and reintroduced as a "new and improved" outboard.

If we look at this advert again
http://www.britishseagullparts.com/40Minus.htm
we can see clearly that BS were interested in saving money as far as production costs go, but also in the development and improvement of their product. I don't think that BS would have rested on their laurels waiting for something to go wrong with their product. Who wants egg on their face!
As i've said, BS were at the forefront with this, always seeking perfection wherever they could find it with the then current industry standards.

I have heard Jeremy mention there might have been a 2 bladed prop somewhere in the line up, possibly with model F's at first, but you'd need to speak to him to confirm this. (i'm really a 102 guy, but i have a keen interest with these little 'uns) BUT interesting you mention the shape of the "bow tie" prop. The 102's from the same time period had this style of prop, and from BS's view its possible to think this same design (just a bit smaller) would do ok in a smaller outboard that we now know as the "little 40".
2 bladed props seems to have a similar theme with both 102's and perhaps the very earliest of "little 40's" of a similar time period, but again you could argue it could have been down to development rather than out of necessity. Maybe it was decided that 3 bladed props worked better with a smaller displacement engine than 2 and that's what BS finally stuck with. Who knows!

I wonder where we've seen bent thumbscrews before? Copied from the older 102's i expect, (slightly weird as we're talking somewhere around 1949/50 here with your advert) but they worked well enough for the purpose they were intended. OR was it one of those things that became too expensive for BS to produce and BS wanted to standardise their thumbscrews across the entire range with something different and perhaps slightly cheaper like the "T" shaped thumbscrews. Again Jeremy's your man for this, i just nod my head in agreement.

Still an interesting topic these little 'uns. Very cute too.

Jon

[Oyster 49]

I’m afraid you have lost me completely. Two long meandering posts and I have no clue what the hell you are on about. Complete nonsense!

[Keith.P]

I will keep it short and simple.

I wonder where we've seen bent thumbscrews before? Copied from the older 102's i expect

I have said this before, if you look at the advert, the little forty has the 102 decal on the tank, 102 throttle lever and thumb screws, a baby 102.

[headdownarseup]

Not nonsense at all Adrian!
Keith and i were discussing how the very earliest of the "little model 40's" took a little while to evolve into what we would commonly recognize as an F,FV,FVP, (perhaps to some people the LS as well) etc. and what was to come in later years with the SJM/P motors afterwards.
If you look carefully there are a few similarities with the 102's from the earliest days of these smaller seagulls as per Keith's images.
This is partly where the data collection comes into play as well.

Right at the start of this thread Keith put up an image of what appears to be a 40 minus in one form or other, BUT look carefully at the cylinder head. No fins and 2 bolts??? To some folks this might seem a bit boring, but i find this fascinating.
This is probably the bit where i went off on a tangent with what fins actually do or whether this was an "experimental" motor, sorry

I agree we have been waffling a bit, but there is a fair bit that's still to be discovered that the rest of us might not already know about.
I think i might have even surprised Charles with my knowledge of 40 minus props. (he hasn't commented about it yet)


I'll shut up now

Jon

[Charles uk]

Jon has anybody established or even thought about when Seagull first used the description "40 Minus"?

A look through your paperwork will tell you.

[Hugz]

When did BS start inscribing props?

[Charles uk]

Not really inscribed Hugo as it sticks out 1.5mm.

[headdownarseup]

Not yet Charles, (i certainly haven't ) but most people that use this site often enough should at least know what we mean by a 40 minus and a 40 plus as it's a term often used on here. The name "model 45" and "seagull 2" are too clinical for a name anyway so i just copy what everybody else has called them in the past instead of "Little model 40 propellers" as that can become a bit confusing to some that don't know. Featherweight is quite an apt description that i think most of us can understand. In this particular thread they're still small props aren't they, or are you going tell us they're not the smallest prop.

I'm sure Keith or Jeremy will put you right about a more accurate date for the description "40 minus", but if the small 4 bladed cloverleaf prop i've shown you is anything to go by i should imagine it was when the LM first came into production somewhere in 1955 that's if Jeremy's own LM has anything to offer on this. Look at Jeremy's list again if you're not sure.
LS props normally have 40 PLUS cast onto them ,i have 3 of them with the same cast information so perhaps the 40 minus description may follow suit with the first of the smaller 4 blade cloverleaf props as well. As i've suggested already, data collection is the holy grail if we're going to try and be accurate here.


When did BS start inscripting props? Maybe right from the start way back in the 1930's, or at least the OA up in my attic has some numbers and stuff inscripted on it. That good enough!
Cast information on props, possibly from late Marston/early SD era. although i will admit i haven't seen them all, but i'm sure there are members that have.
Anyway, i'm supposed to be interested in 102's, what do i know, but i will tell you i have listened very carefully to Jeremy many times before on our meetings. All very interesting to me, but not in a nerdy way.
Sorry to disappoint Charles, but all of my paperwork i've collected relates to 102's so quite useless here in this thread i'm afraid.

I am going to shut up now.
Sorry if it's another long-winded reply.


Jon

[Hugz]

So many words yet I'm having trouble deciphering what you are trying to say.

[headdownarseup]

Have you worked it all out yet Hugz?