That square end hole looks like it fits the main gas tap/union valve, and possibly one to the pipe to fire end joint. The square sockets presumably fit keyways, maybe bleed screws on the old cast iron heating radiators.
I was about to say "Trust Bodger to know about barrels" thinking it was due to his knowledge of beer but then realised the old type of beer barrel was 36 gallons, not 45. Was 45 gallons the standard size of an oil barrel?
Nullius in verba: On the word of no one (Motto of the Royal Society)
Bodge was quite right, the standard oil drum was 45 gallons but Tiz was right about the tool. It's a universal tool produced by Belco that fitted most drain plugs on an engine and transmission. Very roughly made but surprisingly effective as there was a tremendous variation in designs. Next for shaving?
Stanley Challenger Graham
Stanley's View
scg1936 at talktalk.net
"Beware of certitude" (Jimmy Reid)
The floggings will continue until morale improves!
Old age isn't for cissies!
Some great suggestions there and you're getting close but not yet telling me the most important aspect. Yes, it's a cask of alcoholic liquor (not Brylcream, Maz!) but it's not illicit and not smuggling (and not whiskey - or whisky). Pluggy and Stanley are right to mention the First World War. Stanley is correct to say booze sent out to France in WW1, but that is a side issue, not the main objective of this operation. I'll give you a clue. The aircraft is one of a batch of new DH-9s built under licence by Westland at Yeovil in Somerset.
Nullius in verba: On the word of no one (Motto of the Royal Society)
Well done, Ian, that's close enough for me! The photo was taken in WW1at the Westland factory's airfield in Yeovil. The aircraft is one of a batch being prepared for its delivery flight to France. It's a two-seater and unstable in flight without anyone in the gunner's cockpit behind the pilot but they couldn't afford to send two men in each plane and had to use ballast instead. They turned a problem into an opportunity and sent an appropriately sized cask of Somerset cider in the rear cockpit, a strategy that was probably much appreciated at the point of arrival. (Incidentally, the photo shows well the ratchet mechanism for elevating a gun when in position.)
Another Westland story, this time from WW2. The company's designer had come up with a speedier version of the twin-engined Westland Whirlwind. He was very keen on aerodynamics and good at ridding the plane's surface of unneccessary clutter but he went a step too far. He decided that the exhaust outlets were a problem so designed the exhaust pipe to go through the engine nacelle and out the back - which meant it had to go through the fuel tank too. No problem, he said, we'll insulate the pipe to make it safe. The test pilot was a bit leery of flying the prototype when he heard this but didn't want to appear afraid so he took off in the plane. Shortly afterwards, one of the ailerons took on a life of its own and he had to do some quick work with the opposing one to keep the plane right side up. He managed to land and the mechanics did an inspection. The exhaust pipe had blown and the hot gases had burnt through the rod operating the aileron. Had it blown at a slightly different position, where the pipe went through the fuel tank, the plane (and pilot) would have been turned into a fireball. Not surprisingly, they ditched the design. I'd like to have been there to hear what the pilot said about the designer!
Nullius in verba: On the word of no one (Motto of the Royal Society)
Curses, you delight in making me search for another object don't you! Of course you're right. In the old days we used to rip the head off an engine, scrape the carbon off the top of the piston, grind the valves in and lace it all up again, usually within two hours. I'll bet it's a major repair now....
Try this one.... About 10" long....
Stanley Challenger Graham
Stanley's View
scg1936 at talktalk.net
"Beware of certitude" (Jimmy Reid)
The floggings will continue until morale improves!
Old age isn't for cissies!