Starting a radial engine

[GliderRider]

Often when watching a radial engine being started, it is preceded by a fairly long drawn out procedure to clear oil from cylinders, particularly the lower ones, and then prime them.

Given that radial engines are used in aircraft on which the engines are pretty inaccessible for pulling through by hand, e.g. Short Sunderland, Supermarine Walrus, and in armoured vehicles which may need to start up and make a rapid departure, how do these engines get over the oil clearing/priming, and if they can, why don't the others?

I appreciate that some radials have sleeve valves whilst others have poppet valves, but both appear to be used inaccessible applications.

[GliderRider]

Thanks 2x Chevrons! It looks as though even on tanks the first start would be a long drawn out procedure. Having done a bit more research myself I found this: Tank Radial Engine Starting Procedure See the last paragraph on Page 38 & first on Page 39. Clearly they weren't planning to have to make a quick getaway!

[GliderRider]

Thank you everyone for your replies. The information and recollections are much appreciated. It seems the simple answer is that all radials might hydraulic lock and none are particularly user-friendly until they are running.

[GliderRider]

lufbramatt said:

was lucky enough to be allowed to have a sit in the "cabin" in that Skyraider, crazy that they are chunky enough to have 2 seats installed in the fuselage! Didn't fancy a ride in there though, not the comfiest of places

Recalling pictures of Skyraiders with long and wide canopies, I wondered if they were used for Carrier Onboard Delivery (COD). It turns out there was, in the form of the AD-5 version, which could seat 4 in the 'greenhouse', plus another 8 to 10 'down the back'. (2 crew + 12 passengers) That's quite a load!

Edited by GliderRider on Thursday 9th July 20:23