Vickers Potts Oil Cooler

Hi P&P

I remember reading about JM’s Demon rebuild, many years ago in The Vintage Aircraft mag. He saved several tons of Hawker biplane parts that were stored here in the UK, & if it wasn’t for him they may well been scrapped, even though people in the UK knew about them, no one here thought they were worth saving “well done Jack”.

Bob T.

Sorry

Bob, sorry if I might have come across as grumpy or preachy, I appreciate what you are trying to tell me. I really admire some of the folk I come across in the world of engineering, most of them are Gandolf to my hobbit skills. I see what they go through to get a result. I don’t mind paying because for every dollar I spend I often get eight dollars worth of leg up.

I do tend to find a negativity floating around historical aviation restoration that you don’t find in a bonsai class, where everybody is serene and will lend you their clippers and tips on how to stunt a tree. A pessimist would say the historic aviation scene is secretive, brutal in its gossip, barren to the idea of fresh blood and reliant on cancer and crashes for the transmission of artifacts from one custodian to another.

An optimist would point out forums such as these (although I have observed some cruel behaviour) and avenues for willing people to volunteer and be involved in restoration. I guess I am not attracted to complaint, resentment, secretiveness and unhappiness in its myriad miasma of mumbling mishapen moaning malcontented morbid misanthropic misery. Ahh ! I need a beer after that !

By the way I want to resurrect a VP Oil Cooler because I find them amazing, splendid devices, and an easy way to learn about pressing metal, which is what I want to learn about, as well as soldering. I also want to give one to Jack McDonald, who wants to get his Hawker Demon flying. In fact I would ask anybody in Australia who has some talent to consider doing one part for Jack and put him in the air quick because the smile that would erupt on his face would light the dark side of Jupiter. Without Jack scrabbling for parts while everybody else was gooving to the Bee Gees there would be little Hawker biplane flying anywhere.

Hi P&P

I wasn’t knocking Skysport or Retrotec, I have much respect for what both Tim & Guy have done. I was just light heartedly pre-warning you about the possible cost “save’s you possibly having heart failiure when you hear it lol”.

Are you rebuilding the oil cooler for a project your working on ?.

Cheer’s.
Bob T.

Thank you Anne, I appreciate it. You have driven me back to the bookshelf where I have rediscovered my 1937 A Licence Inspection of Aircraft by Pitman where I have now fossiked and read about air driven generators while drinking Coopers stout, antipodean bliss.

I have found out that the proper material was “B.12 Brass sheets, annealed, max stress 18 -24 tons/sq/inch, very soft for small intricate pressings” Materials Of Aircraft Production FT Hill 1934.

I don’t know if these are the materials used on the oil cooler but the B grade solder you quoted is listed in Isaac Pitman’s 1935 Inspection of Aircraft After Overhaul (Category “B” Licence) as:-

Grade B Solder, 50/50 Tin/Lead, 205°C Melting point.

Grade A Solder, 65/45 Tin/Lead, 180°C Melting point. Is recommended for repairs as it’s lower melting point would not affect the grade B soldered joints

It doesn’t list the brass sheet but it gives the composition of the brass tube used in radiators (2.T.47) as.

68% to 74% Copper with the remainder being Zinc.
With impurities as not more than
0.1% Nickel
0.5% Lead
0.5% Iron
0.006% Bismuth
0.005% Any other metal excluding silver.

Anne.

I don’t know if these are the materials used on the oil cooler but the B grade solder you quoted is listed in Isaac Pitman’s 1935 Inspection of Aircraft After Overhaul (Category “B” Licence) as:-

Grade B Solder, 50/50 Tin/Lead, 205°C Melting point.

Grade A Solder, 65/45 Tin/Lead, 180°C Melting point. Is recommended for repairs as it’s lower melting point would not affect the grade B soldered joints

It doesn’t list the brass sheet but it gives the composition of the brass tube used in radiators (2.T.47) as.

68% to 74% Copper with the remainder being Zinc.
With impurities as not more than
0.1% Nickel
0.5% Lead
0.5% Iron
0.006% Bismuth
0.005% Any other metal excluding silver.

Anne.

Hi P&P

I wasn’t knocking Skysport or Retrotec, I have much respect for what both Tim & Guy have done. I was just light heartedly pre-warning you about the possible cost “save’s you possibly having heart failiure when you hear it lol”.

Are you rebuilding the oil cooler for a project your working on ?.

Cheer’s.
Bob T.

Thank you

Hi P&P

I think either Skysport or Retrotech have already produced these parts, so should have the tooling available to make some for you “though I don’t know how many arms & legs they are likely to charge :D”.

Bob T.

Thanks Bob T, will follow up.
I have an old Hall Scott Defender (v12 marine) manual which itemises every nut and bolt and provides a price list, which is the only document I have ever seen which costs 1940’s items of military grade manufacture. Converting this to average teachers salaries from 1940 to 2013 shows that most of the stuff we make today, courtesy of productivity improvements such as CAD, laser cutting etc is actually cheaper than what was made in the 1940s. Given the bespoke nature of parts manufacture for restoration we do not gain much of these productivity improvements but I still see modern restoration production items amortized around runs of other manufactures, eg a bespoke restoration part made by a passionate member of a facility otherwise making lots of boring, profitable things. The stuff is still expensive in an era when LCD flatscreen TVs made by slaves in China can be consumed like bubblegum. I guess this is the frustration I feel in becoming passionate about a hobby based on military grade manufactures where you can’t nickel and dime things.

There is a contrary energy I sense also coming from the party that has poured immense effort into investigating the metallurgy of a part, been forced to buy 5 metres of exotic material from the Swiss to make a 5mm component, diverted from other boring but profitable enterprise that will allow a trip to Disneyland, screamed at by the wife for being late home, only to hand this part to someone who might say “Wot?!, you want 5 quid for this !” These folk then become arbitary in how they deal with the world of restoration. In the end rich folks who don’t ask questions get all the service. As rich folks have spent all their time getting rich, they can’t fly, so aircraft either crash or don’t get flown,or flown by airline pilots too nervous to enjoy the thing ! It’s all so unhappy !

I think the only way around this is to create a new mandatory layer of paperwork to be attached to all items of aircraft restoration manufacture, being a bitchin’ ticket. This triplicate form will allow client, manufacturer and bureaucracy to write down their respective grievances. Settlement of any transaction could only occur over pints of beer, with each party airing their respective positions as laid out in the approved manner in the ticket, and hopefully being carried out in the one wheelbarrow at closing time. We could be happy !

Hi P&P

I think either Skysport or Retrotech have already produced these parts, so should have the tooling available to make some for you “though I don’t know how many arms & legs they are likely to charge :D”.

Bob T.

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