I flew the Convair 240 which had two Pratt and Whitney R-2800 radial engines. The aircraft was designed by airline pilots in 1949 and had all the latest technology. The engines were started by electric starters that were powered by a small petrol engine
located in the tail, much like the APU's of today's jets.
The procedure was to use the starter motor to run the engine through "5 blades". Usually the ground crew has already turned the engines by propeller to ensure that there is not a lot of oil sitting in the lower cylinders which would cause a hydrostatic
lock and most-likely blow a cylinder off the block. By motoring the engine for 5 blades you are confirming the engine is not locked plus circulating a little oil. After the 5 blades you introduce fuel through a toggle switch and high voltage spark to
combust the fuel. The magnetos are on and will provide the normal charge to the plugs but this high voltage switch really ensures a smoother start. As you toggle the fuel switch you slowly advance the mixture and the engine will start to run on its own
and you can release the fuel and high voltage toggle switches. The co-pilot counts the blades for the captain on the number 2 engine. The captain counts blades on the number one. It really did take two pilots to get an engine started to make a smooth
transition from start phase to run phase. There were hands going all over to keep the engines running. The captain's right hand would work the start toggles and his thumb was pushing up on the toggle that activated the start switches.
It was a lot of fun flying that old bird. In my later career flying jets you just push the start button and monitor temps. Too easy!
On Wednesday, November 3, 1999 at 7:00:00 PM UTC+11, Charles K. Scott wrote:
In article <3820467F...@americasm01.nt.com>
Phillip Hopkins <p...@americasm01.nt.com> writes:
I wonder if someone, who is knowledgeable on the subject, could describe the
methods used is cranking over large radial engines during starting, such as those on B-17s, B-29s, B-36s, even DC-3s. A brief history of radial engine starting techniques from the 1920s to the 1950s would also be very interesting.
Thanks in advance.
Phillip Hopkins
Having sat in the jump seat on many occasions of the company DC-3 that
my father flew back when I was a kid I can verify that an electric
starter was used to get the engine going. B-17's used Wright Cyclones
and they were started by electrical starter as well. Same for the
B-29's and B-24's.
In watching flight deck operations from many documentaries and films I
can verify that many of the Navy's WWII aircraft used electric starters although I think the F4F may have used a starter cartridge.
Corky Scott
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