Help with Bristol Bulldog Boost Gauge

Bulldog Mk1..sorry about the “control lock” across the face.

Kind Regards Mike

Looks like a MK1 or 1a.
I have something along those lines, but think it’s a civil one as no 6a number on it.

Bob T.

Not from NZ, from UK. Something not right, call for a beer…

Everyone has their Demons Ed

Come to think of it…did you get that Boost from NZ? If so it was one of mine !!

Sorry Ed they are all spoken for..except for the post war.

2 Demons!? :p

Mr Storo, your Bristol F2B, I think, holding pace with RAAF Hornet recently :

https://m.facebook.com/story.php?story_fbid=10153944554122639&id=88014372638

The gauge you need is the prewar Negretti & Zambra 3.25″ diameter for Wasp 1340 :

[ATTACH=CONFIG]246552[/ATTACH]

This was found at the feet of a Yeti while I was searching for Yeti scat.

[ATTACH=CONFIG]246553[/ATTACH]

If you want, PM address and will send.
Ya gotta be getting close now….

Sorry Ed they are all spoken for..except for the post war.

bulldog cockpit Mk II

[ATTACH=CONFIG]246549[/ATTACH]

Mike,
I did some digging in my reference material and ran across AP 1275. It shows the Mk IIA as an “A, B, C” model. (6A/448, and 350 luminated, -4 to +4; 6A/449, 441 lum. 0 to 8lbs; 6A/487, 486 lum. -4 to +8. respectively) I have a dimension of 3.45 on the line drawing, but no reference from whence it came. Rats. Also I found a copy I made of a chart from FLIGHT magazine from about 1943 that shows -4 lbs to equate to 21.8″ (on US aircraft), and +4 lbs to equate to 38.1 “. Thus the third one and the second one would be perfect. Are they yours? Putting in the 2 1/2” size would just be wrong. trying to upload a photo of the Bulldog cockpit, but failing
Ed

The Bristol Boost gauge 6A/195 6-8lb Mk 1A, size not known to me.
” AM ” ” 6A/350 4-4LB Mk IIA , 3 1/4
” AM ” ” 6A/486 4-8lb Mk IIC, 3 1/4
” AM ” ” 6A/699 4-8lb Mk IIIC, 21/2
The larger boost gauges are not a standard 3 1/2 for what ever reason,as far as I can tell they are the only 3 1/4 sized AM gauge (Happy to be corrected though!)
It could be that the Bristol gauge is 3 1/4, and for what ever reason this size may have been adhered to, as it was the pioneer.
The larger gauges stop with the introduction of the Mk III, but just to do your head in, post war there is large boost gauge..you guessed it 3 1/4.
The 6A numbers in the 2 1/2 size that may suit your needs are 1427 Mk IIIL 8-20lb , 1581-1582 Mk IIIM 7-24lb.
Kind Regards Mike

Thank you “one eighth bit” and Mike. The picture that Mike put up shows the “Bristol” boost gauge in the lower left, i.e. it is not located on the panel itself. The Bristol gauge seem to be a bit larger than the standard 3 1/2″ gauge. I am using an approved modification in that I am using the newer style airspeed gauge, which it so happens is 3 1/2″ dia. So it makes sense that there would be a small and large size instrument. By the way, the other gauges on the panel are in the 5″ range which the RAF standard was replacing.
The question is….which of the boost gauges on ebay etc. are of the 3 1/2″ size? Most boost gauges shrunk to the 2 1/2″ size. Next, as I am having to use a Wasp 1340, the max boost would be about 36″ which should equate to the 17lbs in the boost vernacular. So I would guess that something in the 22- 24″ range max on dial would give the proper amount of instrument read out. Any guess as to the size of a Mk III? or any help at all.
Thanks guys.
Cheers
Ed

Bulldog Mk1..sorry about the “control lock” across the face.

Kind Regards Mike

Ed,

http://forum.keypublishing.com/showthread.php?125686-MK-I-BOOST-GAUGE

Dug through my 1924 AP1086 and that gauge is added in AL.1, October 1924:

“6A/195 – GAUGES, Booster – For super-charged aircraft engines”

I’ve got a couple of aeronautics books which have dimensioned drawings of a 3.25″ diameter boost gauge. But it might be the later MkII type.