Bristol Bulldog 1A aerofoil

I found the NACA No. 240 report on line.

https://archive.org/download/nasa_techdoc_19930081042/19930081042.pdf

Hopefully BA 643 will surface. I purchased a copy of R&M 1383, but to my dismay there is little information out side of the ordinates. But, the fact that this aerofoil is included
in this paper would suggest that there is a paper-study-report on aerofoils at positive incidence. I spent some time researching the R&M index, but have not found any information
that jumped out at me.
The main outcome of the R&M 1383 report is that most of the airfoils acted the same with neg. incid. and that the C.P. moves backward as you point the nose down.

Thanks to both of you two for showing interest.

Ed

No teasing I’m afraid. The 1a profile is only really mentioned as an example in this book, giving values of a couple of parameters but no dimensional data.
Reference is also made to R & M 1383 (Wind tunnel tests on aerofoils at negative incidences) as well as B.A. 643. I suspect that B.A. 643 will reveal all if it can be located.

Where is the Bristol 1A information? (B.A. Report 643)

Please do not keep us in suspense.

Cheers,

Ed

Thank you

Bingo

At the risk of drifting off the thread topic….

The steel back bearing shells were invented by Norman Gilman and patented by the Allison Engineering Company (later bought out by General Motors) in the early twenties. After trying to come up with a number of solutions to bearing problems in their engines, Rolls Royce ended up obtaining a license from Allison for the steel backed bearing shell technology and paid a royalty on every engine for it (along with just about every other major engine manufacturer…:))

Gold !
(I will start another thread once I hit a new wall on these bearings…)

Ok here is the data on the Clark aerofoils (sometimes browsers just do not do what they are supposed to do!). Using another browser in this case has solved the problem.

At the risk of drifting off the thread topic….

I am trying to figure out the logic of cast in copper (gunmetal?) bearings, replaced with removable bearing shells in RR Merlin.

The steel back bearing shells were invented by Norman Gilman and patented by the Allison Engineering Company (later bought out by General Motors) in the early twenties. After trying to come up with a number of solutions to bearing problems in their engines, Rolls Royce ended up obtaining a license from Allison for the steel backed bearing shell technology and paid a royalty on every engine for it (along with just about every other major engine manufacturer…:))

do you know if the R engines on Schneider racers had cast in copper bearings at conrod big ends.

As far as I recall they were white metal substituted after the early inserts (phosphur bronze?) failed under load. I’ll check and confirm/update later

Update……yes, white metal

Found some data on the Bristol 1a, it references to report, B.A. 643

Thanks ac, will pm

From http://aerospace.illinois.edu/m-selig/ads/coord_database.html#C

CLARK YH AIRFOIL
16. 16.

Schneiderman, thank you.
While I am on Schneider stuff, do you know if the R engines on Schneider racers had cast in copper bearings at conrod big ends. I understand RR Eagle did and RR Kestrel has, but I have seen references to ‘white metal’ on R engines. I am trying to figure out the logic of cast in copper (gunmetal?) bearings, replaced with removable bearing shells in RR Merlin.

Found some data on the Bristol 1a, it references to report, B.A. 643

Here is the data I have on the Clark YH.

The uploading function does not want to work today!!!

You may have to PM for the file.

I have the data for the Clark YH profiles, I will scan then for you later.

There is a note with this data saying see, N.A.C.A, Note No 240.

Thoughts

According to Bristol drawing # 12356-1 Top Wing Standard Rib and #12497-1 Bottom Wing Standard Rib. After interpolation to the ordinate system, these ribs are the same aerofoil.

David Luff’s book “The Bristol Bulldog” states that the lower wing was a Clark YH. He must have taken this from Andrews book. The aforementioned ribs are for the Type 105 dated 1927.

The YH and 1A are very similar when placed on top of each other. (I have drawn this) Perhaps the YH is the father of the 1A. P&P is admirably spearheading a quest to find more information on the 1A. Correspondence to Bristol Heritage group has so far produced nothing. (please-please let us know if you have said info)

The Bristol 1A ir supposedly the father of the RAF 34 & 35 aerofoils. (This will impress any girl you ever meet.)

Ed 1

Ed, I have 1925 dated patent for Bristol spar used in Bulldog and a lot of steel aircraft literature from the time relates to corrugated spar design. I figure that Bristols designed its spars first, then sought an aero foil to both fit the spar geometry and performance characteristics it was seeking. Perhaps in the process of compromising between limitations of geometry they needed to slightly change the YH to make everything fit, birthing the proprietory 1A without sacrificing YH performance or needing to change their spar dimensions which would require new roll form tooling, not possible on a private venture prototype after years of not winning Air Ministry contacts. Hey I am typing this on an iPhone for the first time and it is ok! I am in a factory yard surrounded by brown snake filled grasslands and it is 40 degrees C. Warm wishes !

According to Bristol drawing # 12356-1 Top Wing Standard Rib and #12497-1 Bottom Wing Standard Rib. After interpolation to the ordinate system, these ribs are the same aerofoil.

David Luff’s book “The Bristol Bulldog” states that the lower wing was a Clark YH. He must have taken this from Andrews book. The aforementioned ribs are for the Type 105 dated 1927.

The YH and 1A are very similar when placed on top of each other. (I have drawn this) Perhaps the YH is the father of the 1A. P&P is admirably spearheading a quest to find more information on the 1A. Correspondence to Bristol Heritage group has so far produced nothing. (please-please let us know if you have said info)

The Bristol 1A ir supposedly the father of the RAF 34 & 35 aerofoils. (This will impress any girl you ever meet.)

Ed 1

From http://aerospace.illinois.edu/m-selig/ads/coord_database.html#C

CLARK YH AIRFOIL
16. 16.

0.000000 0.041000
0.025000 0.068000
0.050000 0.081000
0.075000 0.090000
0.100000 0.098000
0.150000 0.108000
0.200000 0.113000
0.300000 0.119000
0.400000 0.114500
0.500000 0.105000
0.600000 0.091000
0.700000 0.075500
0.800000 0.056000
0.900000 0.037000
0.950000 0.028500
1.000000 0.021000

0.000000 0.041000
0.025000 0.018500
0.050000 0.012000
0.075000 0.007000
0.100000 0.004500
0.150000 0.000000
0.200000 0.000000
0.300000 0.000000
0.400000 0.000000
0.500000 0.000000
0.600000 0.000000
0.700000 0.000000
0.800000 0.004000
0.900000 0.010000
0.950000 0.013700
1.000000 0.020000