Stirling project appeal for odd size control pulley wheels

Hi Waynne

They’re more than likely going to be to US standards which are a different size to UK AGS types, I’ve investigated these before and unfortunately they’re not a close match

John

http://www.ralmark.com/products/
Although a US firm I know they have supplied a Waco glider project. This is a quote from their website: These pulleys are in continuous production in our factory. Derivatives of these standards can be offered for special applications.

Cheers for the help, Unfortunatly our only coupe drawing is an early GA. no pulley block detail. We spent some time on the wreckage at the weekend and although they are swollen we all agreed they would have been 1.5” total external and 1.25 where cable seats. the bore of the bearing escapes my memory but it is large ie something like 3/8”. Graham is drawing them up.
We are going to give it another week to try and find some and then if no luck we will have some made. Kev

That pretty much matches what we’ve got. I suspect that looking at the one you sent, that it’s a pretty close match, confirmation should come on Saturday. It wouldn’t surprise me though if Shorts used there own spec pulleys in places

John

Keep in mind that the SBAC “Aircraft General Standard” wasn’t an RAF standard but the aircraft industry one. The whole point was to standardise parts to make life easier to the designers and supply chain. Shorts would of used these stock sizes where possible.

If you can’t find it given in the AP or schedule of parts check the drawings, especially in the bill of materials in the corner. In our case we found our pulley hidden in an Airspeed drawing. We got the part from the BOM which listed “SBAC AS 104 Pulley”

This Brown Brothers catalogue lists the fibre pulley sizes on page 183, including AS111. The next size up is 2.4″.

https://www.google.co.uk/url?sa=t&source=web&rct=j&url=http://www.chilton-aircraft.co.uk/Images/brown%2520brothers.pdf&ved=0ahUKEwiqkbXjnKrKAhVIXR4KHU0AA0gQFgghMAM&usg=AFQjCNEDeIeLqspSjzKeNE4k5kDKo4SddQ&sig2=XJCyX_B3yoZVeC5F-zTiJw

That pretty much matches what we’ve got. I suspect that looking at the one you sent, that it’s a pretty close match, confirmation should come on Saturday. It wouldn’t surprise me though if Shorts used there own spec pulleys in places

John

Thanks Alan

Guessed as much. It seems to be the one aircraft for which there’s no parts catalogue!!!:rolleyes:

Not off-hand, sorry.

The National Archives doesn’t seem to have much on the Stirling (at least not in Air10 where the APs ought to be). Navigator lists five copies of the Schedule of Spare Parts held by RAFM but I assume these are just the assorted Amendment Lists you’ve already seen.

Also, if you haven’t already seen it, War equipment schedule for a Stirling (Bomber) Squadron, 1941, AP1825, Object Number 012899 should have lots of useful info, inc Stores References, etc. Not necessarily those pulleys, though!

This Brown Brothers catalogue lists the fibre pulley sizes on page 183, including AS111. The next size up is 2.4″.

https://www.google.co.uk/url?sa=t&source=web&rct=j&url=http://www.chilton-aircraft.co.uk/Images/brown%2520brothers.pdf&ved=0ahUKEwiqkbXjnKrKAhVIXR4KHU0AA0gQFgghMAM&usg=AFQjCNEDeIeLqspSjzKeNE4k5kDKo4SddQ&sig2=XJCyX_B3yoZVeC5F-zTiJw

Doesn’t the Stirling Project have access to the Stirling Spare Parts Schedule or its associated Appendix A? They should be in there somewhere?

Hi Alan

We haven’t unfortunately, the only info we’ve been able to glean for the aircraft is from the Vol 2 and the little info that RAFM has (some assorted Parts schedule amendment sheets).

Silly long shot question but would you happen to know if one exists?

John

I don’t have a WW2 era BBros catalogue but I do have a 1942 edition of AP1086 Book 12 which lists standard AGS parts.

Under pullies is listed the AGS666 series (in internet references, these are thrown up as pulleys “for Main and Engine Controls”. In AP1086, they are only listed as 5 cwt, 10/15 cwt. sizes etc, without dimensions but, crucially, they are manufactured out of Duralumin as are, I believe, all earlier standard types.

If yours are moulded plastic, my betting is on the AS111 spec. pulleys, unless Short’s produced a version of their own for some reason.

Doesn’t the Stirling Project have access to the Stirling Spare Parts Schedule or its associated Appendix A? They should be in there somewhere?

Has anyone got a Brown brothers catalogue from say 1939, it should show if a 1.58” or thereabouts existed at this time. Our volume is later. Kev

thanks Elliott

🙂

Hi John

Pm sent

Hi Elliott

received the Pulley yesterday, for which many thanks :), we’ll offer it up to the originals on Saturday and I’ll let you know how we get on. Out of interest, if they are suitable, how many of these have you got?

regards

John

Hi Waynne

They’re more than likely going to be to US standards which are a different size to UK AGS types, I’ve investigated these before and unfortunately they’re not a close match

John

P3’s are full of these all the way from the flight station to the tail.

Know anyone in the States in the boneyard?

Funny thing – I’ve just spent the best part of 6 months learning about Tufnol pulleys trying to figure out the sizes we need for the Horsa (AS104 as it happens).

Pulleys, like pretty much everything else came in stock sizes to a given AGS spec so the fact that you measure yours at 1.58″ I would put down to them distorting. More than likely they were 1.4″ pulleys like Elliot has. The original ref was AS111 which gives a overall diameter of 1.4″, groove diameter of 1.15″ and a bore size of 0.25″

Spec changed to be known as SBAC AS111 and RHP Aerospace in Stonehouse were still making them as CP1.15 until SKF took over. SKF sold all their old stock to Saywell International – give them a call and ask for a price if you’d like a laugh. They wanted £129 per pulley last time I asked and that was NOS with no certification. :stupid:

I believe the aerospace arm of SKF, Sarma, still makes pulleys to the original spec as AS111 as part PV29SP1 but I have no idea what they cost or a source but sometimes you can get lucky on eBay. I looked at some of the US spec pulleys as alternates but they all use different bore sizes and even those come in at around £20 each + shipping from the US.

Best bet – if you can’t source originals – I found a company that turns Tufnol using a CNC lathes and said they could easily make new ones from my CAD models for about £10 each. They won’t have roller bearings and you’d need to hammer in your own brass sleeve inserts instead but for a Static cockpit their more than suitable.

Super pic, fingers crossed, Kev

Here’s a pic for you and Kev in the meantime

Hi Elliott

Many thanks, PM sent :applause:

John

Hi John

Sure. If you pm an address i’ll send you one. I have a number of these pullies – they do not fit the Whitley so they are up for grabs.