Author Topic: ft t35 generator  (Read 1265 times)

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Offline flea

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ft t35 generator
« on: 15 May 2022 at 23:19 »
any one know what spark plug the ft35 generator used and was it the same as the 1947 t35 mark 1

Offline eddie

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Re: ft t35 generator
« Reply #1 on: 16 May 2022 at 06:00 »
Not sure what spark plug was fitted, but it wasn't the same as the T35. The plug and HT lead fitted to the generator engine was fully screened to eliminate radio interference.

    Eddie.

Offline RegH

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Re: ft t35 generator
« Reply #2 on: 16 May 2022 at 09:49 »
According to the handbook for the generator sets, the spark plugs used were Lodge SE14 or KLG RE41. Not sure what the equivalents are nowadays. The plug gap was 0.015" - 0.018" The plugs for the T35 motorcycle were either Lodge C.14, KLG F.50 or Champion J8.
Reg

Offline cardan

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Re: ft t35 generator
« Reply #3 on: 16 May 2022 at 11:39 »
https://usmtwt.com/en/boutique/autres-vehicules/non-identifie/bougie-klg-re41/

They're funny-looking things. Of course you need the correct magneto with the shielded pick-ups and the shielded plug leads. Yell if you do need the shielded plugs, as a I have a box full of NOS ones I can have a look through.

Leon

Offline EW-Ron

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Re: ft t35 generator
« Reply #4 on: 16 May 2022 at 22:17 »
They're funny-looking things.

The top of them is made for that threaded screw-on fitting on the plug leads.
Same as aircraft use - so the plug leads CANNOT fall off.

Offline cardan

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Re: ft t35 generator
« Reply #5 on: 17 May 2022 at 02:41 »
Most of the shielded plugs in my box turned out to be Champion RC35S, which are 18mm.

There was only one 14mm shielded plug. No brand, but stamped with the WD broad arrow and "R.C.5/3". It looks very similar to the KLG RE41 used in the generator.

Interestingly the knurled brass fitting is still present, and the porcelain insert for the plug lead. I was surprised that there is no method of grounding the outer braided shield of the plug lead at the spark plug end. Presumably it is grounded at the magneto end? Maybe mine has been mucked around with... Also surprising is that there is no mechanism to clamp the lead from the outside: the outer braid just rests in the porcelain insert while the wire core passes though the porcelain into a metal fitting inside where it is wound around once to hold it in place. Not as fancy as I had expected.

Wartime BTH magnetos with shielded HT cables pop up from time to time - as well as Douglas there was a Triumph generator set, both needing 180-degree magnetos.

Leon

Offline flea

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Re: ft t35 generator
« Reply #6 on: 17 May 2022 at 06:08 »
thanks for the replies as it will all add to my very basic knowledge of these generators , bloke who i got the first 1/2 of the generator off dropped off a box of plugs which he thought might have belonged with it but i thought they might have been the wrong ones , they were champion  n21 , definitly now know wrong ones (for vintage victor lawn mower) the ft35 ones are very strange ones indeed and think will have a lot of trouble finding any .. didnt realise the magnitos were different as well , got a magnito with the generator but dont know if its the correct one so any identifying marks would be great as got a few bits of a t35 with it .. basiclly was just the motor in the bottem frame , magnito , and guages , t35 rear frame section and front fork tin wear ... will be chasing parts in the wanted section if anyone has any

Offline cardan

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Re: ft t35 generator
« Reply #7 on: 17 May 2022 at 07:02 »
Actually I'm not sure if the magnetos are different or not - certainly the pickups are. The attached photos shows a typical setup (this one is a base-mount BTH MD2).

Of course the generator set could be built up with unshielded cables and plugs.

If you post the Model (MC2, MD2 etc), Form and Number stamped on the plate on the magneto I can probably date it.

Leon

Offline eddie

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Re: ft t35 generator
« Reply #8 on: 17 May 2022 at 08:03 »
I heard that the generator mags were built to a higher spec than the motorcycle mags (something to do with them being built during wartime under a government contract!).

  Eddie.

Offline cardan

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Re: ft t35 generator
« Reply #9 on: 17 May 2022 at 08:40 »
BTH offered the "DIRT TRACK MAGNETO" and the "TT MAGNETO", which could look identical to a similarly-specced standard magneto. I've heard it said that these may have had better quality build, perhaps like magneto coils wound from a single strand of wire, with more careful insulation, and of course nothing that was susceptible to alcohol fuel. I'd really love to know exactly how they built these higher-spec magnetos.

All the spec is described in the "Form" stamped on the magneto plate - stuff like the points cover, a/r mechanism, pickups, mounting detail etc. - which from the late 1920s until the 1960s ran 1, 2, A, B, C,... Z, AA, AB.... with a number that is usually specific to the point cover. Presumably somewhere at BTH there was a list (or perhaps a card file!) of the spec for each Form, but I've never seen it in the public domain.

Leon

Offline Hutch

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Re: ft t35 generator
« Reply #10 on: 18 May 2022 at 03:03 »
Hi All,
I had  a quick look on what info. I have on BTH magnetos. Not really very much at all unfortunately, but I did find a link from a year or two ago to a factory blueprint CY108 381 of the BTH MD1 / MD2 with TT end plate and cover which may be of interest:-

https://twitter.com/vmagnetos/status/1223619234632208386

Looks like the original post was by Carl Kenney of Vintage Magnetos.

Maybe more detailed factory information is still around (...mainly in the hands of the magneto specialists?) but it appears to be very hard to find on the web!

Edit: I don't know the timeline of the variants of MD1 /MD2 BTH magnetos but I just noticed that the Blueprint was dated 1946 (Not a good scan but that is what it looks like) so maybe why there are a lot of similarities between the war time generator magnetos and the TT versions? i.e. using up left over WW2 stock?

cheers

Hutch
« Last Edit: 18 May 2022 at 03:18 by Hutch »

Offline flea

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Re: ft t35 generator
« Reply #11 on: 18 May 2022 at 23:14 »
thanks hutch , as you said bit hard to read the scan but going to ask a computer savey mate to see if he can enlarge / clean it up , as you said the tt most probably used ww2 left over parts same as the 1947 t35 .. thanks to everyone here learning more and more on both my t35 and the ft35 .... its actually amazing that the 2nd 1/2 of the generator parts actually came from a almost complete generator , the owner put it up for sale with no takers except 1 bloke who only wanted it for the motor , was sold in the boteem part of the frame for shipping (probably with the magnito as well) and now here i am trying to put it back together again ...might be a few still around in the uk but fairly rare in australia

Offline cardan

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Re: ft t35 generator
« Reply #12 on: 19 May 2022 at 01:51 »
Elsewhere on the forum there are various mentions of the FT35 generator set, accessed by the search function.

In particular there is this post: https://www.douglasmotorcycles.net/index.php?topic=7201 which shows the magneto with a readable plate (below). This particular generator has a BTH MD2 P4 magneto which dates (from the serial number) to October 1943. Note that is has shielded pickups, but at some stage the shielded HT leads and plugs have been replaced. Cable on the manual a/r - other forms (maybe built for a different contract, or different customer) have a thumb screw.

"I don't know the timeline of the variants of MD1 /MD2 BTH magnetos..."

M refers to low (35mm) armature height, and the second letter describes the magnet. D refers to a ALNI (aluminium nickel) alloy magnet, first introduced in 1934. (Note that BTH continued to build C magnetos (e.g. MC2) with cobalt steel magnets long after 1934.) I've not seen an MD2 from the 1930s, but they were certainly common in wartime, and were still being made at least as late as 1957. The MD2 Forms I have seen are T8, AG8, N4, P4, N8, AW4, S4, AB6, AT4, and X4. (A few of the MD2 Forms were made at BTH by machining 10mm off the bottom of a KD2 (45mm spindle height) casting, surprisingly using a lathe. The BTH inspection marks are stamped over the circular machining marks on the base.)

Thanks for posting the link to the MD1/MD2 TT MAGNETO blueprint Ian. Very interesting. This must be the "generic" drawing, so that the different Forms of the MD TT MAGNETO (e.g. the MD2 AB6, or the single-cylinder MD1 AB6) are described by noting variations from the generic version.

One of the magnetos I have in my spreadsheet is a MD2 AB6 TT MAGNETO built in February 1951. Would this have been used on a racing 90 Plus?

Leon

Offline Hutch

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Re: ft t35 generator
« Reply #13 on: 20 May 2022 at 05:01 »
Thanks Leon for the info on BTH M1 / M2 variants - I have multiplied my knowledge at least 10 fold I think!. In my collection of stuff I have a BTH M2, presumably from WW2 but appears to have been partly converted to motorcycle use. It is a MD2 T8 variety. After looking at this thread and others on Douglas Generator Sets I was intrigued as to what it was off so did a bit of digging on the web.

This info may be well known to those with WW2 generator sets so apologies if I have repeated info already on this forum (I did do a very quick search.....)

I found that there are documents known as Vocabulary of Army Ordnance Stores (VAOS) so went looking for archives that might contain such documents and in the short time I was searching I drew a blank. If I get some more time I will look deeper. Somewhere there should be a master spares list (may be LV6 MT8 but not sure) that might list BTH magnetos and what they were used for.

I also found there should be REME EMERs for the equipment as well, but failed to find those also. Then re-reading some posts on generator sets I realised I probably should be looking at RAF instead of the Army and found this interesting site;

https://www.blunham.com/Radar/index.html

In there is AP1086 Vocabulary of Royal Air Force Equipment. Looking a bit deeper I found

AP1186E Volume 1
Royal Air Force Manual
Electrical Equipment (ground)
Section 7 Test Sets
Chapter 3
Douglas Generator Set (42Y/1000)

it can be downloaded here;
https://www.blunham.com/Radar/SignalsMuseum/PDFs/AP1186_1.pdf

(I read the text at the top of the pdf and obeyed the wishes of the person who scanned the document)

I'm sure that this info is probably well known (?) but thought I would post it just in case.

I'm still looking for the info on the BTH magnetos but this might be enough searching for this week! :-)

EDIT: Looks like I need to find AP 1086 Section 16E MT Electrical Systems......?

cheers

Hutch
« Last Edit: 20 May 2022 at 22:40 by Hutch »

Offline cardan

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Re: ft t35 generator
« Reply #14 on: 20 May 2022 at 08:41 »
Hi Ian,

Yes your BTH MD2 T8 is another of the 180 degree twin magnetos for stationary engines, with shielded ignition and thumbscrew a/r. The example in the photo below is from 1950, and uses the heavier KD2 casting with 10mm machined off the bottom by BTH themselves.

I started researching BTH magnetos about 7 years ago and found nothing much at all; even the "experts" I contacted didn't have much info. So I gathered info from 550 BTH magnetos (in the shed, on bikes, on the internet...) and built these into a spreadsheet of serial numbers, models, forms and features. Plus all the info I gathered from other sources. Of the 550 mags in the spreadsheet, only 2 or 3 don't fit perfectly into the pattern (maybe mis-stamps?), so I reckon I can date to the month any BTH MC, KC, MD, KD, MH or KH magneto from 1929 into the 1960s, by which time the mags were branded AEI. Unfortunately the earlier horse-shoe-magnet K and M magnetos don't fit into the same series of numbers, so I know precisely nothing about them!

I did all this because I wanted the answer to one question: what magneto should be fitted to my 1932 Works Rudge? It was certainly a BTH TT Magneto (even though Rudge were fitting ML magnetos on all their bikes at the time), but which model and form, and how would I know if it was the right date? Anyway, the bike was raced in the TT in June 1932, and after seven years of research and searching I have just acquired (for a staggering amount of money from a seller who knew nothing about it) an MC1 E6 TT Magneto with a build date of... June 1932. It is the earliest TT Magneto I have seen (they were introduced for the TT in 1931) and is extremely close to the correct specification for the bike. I am thrilled, even though most people wouldn't notice if I fitted a KD1 C6 TT Magneto off a mid-1950s BSA Gold Star!

Cheers

Leon

Offline flea

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Re: ft t35 generator
« Reply #15 on: 20 May 2022 at 23:28 »
this gets more intresting and confusing all the time ,a lot of my assumptions are going down the drain , the first 1/2 of the gennie i found was on the atherton tablelands just about 1 mile from the largest military hosp in the southern hemisphere .between 1943-45 it treated over 60000 service personel with 2000 staff (most of which was done under canvas) there were about 100000 service personel on the tablelands at any one time (mostly training for png and the pacific) , though there was a air force base at marreba would think my geni would have been army issue as most of the hosp staff and service personel were army ,also mine is in a frame ment to be carried rather than stationary .. hopefully will get it to the stage of being mocked up if not running so can be loaned out to a couple of museums etc around here for their events (lol ,, live bombs and ammo are still being found around here from their war games )

Offline Hutch

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Re: ft t35 generator
« Reply #16 on: 21 May 2022 at 03:18 »
Hi Leon,

Fantastic that you got the TT magneto to suit your Rudge - nice when all the effort of the research pays off! :-) .
The BTH MD2 T8 magneto I have is serial number 5J1 57207 for you add to your database (tho' it may already be there!). Stamped on the base (not machined as you described but has 4 square raised sections (say approx. 1mm high in each corner) are the numbers

L3
15929
11 C6168

I assume this to be the WD parts identification for this magneto?. Looking on the web at similar (but lucas WD magnetos) it is possible that the "C6168" part of the code related to the WD contract that the part was supplied under but not really sure.

Looking at AP 1186E  I notice that the BTH (I assume it is BTH) magneto shown in the Norman T300 engine powered generator set in Section 7 chapter 2 has a base design similar to your TT magneto and that the body of the magneto, although a "M2" is different to the T8 variant. So obviously quite a few different versions around by the looks. I noticed that the variants of the WD Lucas magnetos had similar, but maybe not exactly equivalent forms to the ones you described (i.e.  - so maybe points to one way of sorting out what the codes mean for a BTH magneto?)

Hi Flea,

I'm sure that there are Army variants of the Douglas generator sets and the RAF version in AP 1186E  is only one of many. I found this old post on this forum from REME245;

https://www.douglasmotorcycles.net/index.php?topic=4065.msg14587#msg14587

and it shows a different frame. A quick search of the web shows  similar framed generator sets but with different engines so this could well be a "generic" Army type - I don't know. If the VAOS for the generators can be found then hopefully some mysteries would be solved??

There was quite a lot of war time activity in Queensland in WW2 that not many people seem to know about. Quite a while ago I came across this website and found it quite fascinating - you have probably already come across it?

https://www.ozatwar.com/ozatwar/militarycamps.htm

Keep clear of the live ammo and bombs! :-) Some old stuff is still being dug up around SE Qld WW2 sites now and then - usually when the areas get developed for housing!

cheers

Hutch

(EDIT : - fixed some typos)
« Last Edit: 21 May 2022 at 03:27 by Hutch »

Offline cardan

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Re: ft t35 generator
« Reply #17 on: 21 May 2022 at 04:32 »
Hi Ian,

MD2 T8 5J157207 dates to August 1955 - I've seen other T8s with build dates between 1950 and 1957 so they were built for a while.

You'll note that the reduced-height 'KD' casting is quite different from the 'MD' casting, which is usually (!) quite simialr to the base of my MC1 TT. The K series casting has bulkier mounting bolts (3/8" vs 1/4"), is generally sturdier, and probably heavier.

Sorry I don't know anything about the other numbers, except to say that weird other numbers are commonly stamped on BTH magnetos. I've never looked into them because my primary interest is with the early racing magnetos.

Not sure how the K castings were machined down in the 1950s, but this is how they did it for racing TT magnetos in the 1930s. The little inspection stamps are almost certainly BTH - stamped after machining. Notice the half-missing BTH stamp on the side of the base!

Flea - sorry to confuse. The take-away is that there were numerous Forms of BTH MD2 magnetos with shielded HT that were used for different applications. I doubt anyone will notice the difference between a P4, S4, T8 etc, and they changed very little between the early 1940s and the late 1950s.

Cheers

Leon


Offline Hutch

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Re: ft t35 generator
« Reply #18 on: 23 May 2022 at 23:39 »
Thanks for the dating info. on the MD2 magneto Leon. Its a bit later year than I first thought it would be but good info. to know . I dug out a M2 AD4 magneto and apart from the high horseshoe magnet,  it appears to be much the same body as the one on the Norman T300 (but this has the lower magnet similar to the MD2). The M2 AD4 body is different to the MD2 T8 magneto. Not sure when they changed body styles tho' . I will look into this some more if I get some spare time!

cheers

Ian

Offline cardan

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Re: ft t35 generator
« Reply #19 on: 24 May 2022 at 01:28 »
BTH magneto development, and naming, was all about magnet technology: the order of introduction is M, MC, MD and finally MH, which had magnet steels of, respectively, tungsten, cobalt, aluminium-nickel, and "ALCOMAX III". So amazing was the development that the ALCOMAX III magnets of the late 1950s could produce the same field as the M-series horseshoes from only 3.8% of the volume. A lot of the steel in later magnetos is in laminated pole pieces to shape the field - the permanent magnet is just the little thing at the top.

The dating problem is that BTH continued to build earlier-style magnetos long after the new models were introduced, and an MC1 from 1948 is barely distinguishable from an MC1 from 1929, despite the MD1 introduced in the mid-1930s. Ditto for MD magnetos made long after the MH appeared.

Leon