Finally got my hands on one!

[Railrunner130]

Didn't Tim do one already? A new one would be cool!

If I recall correctly, it was a blast for a piston aerobatic airplane.

XX540 and XX550 would indicate to me that they were probably in a block of aircraft that was sold to the civilian world. I assume XX is for the Bulldog type. I'm not sure where they came up with the three numbers, but it would appear that 540 and 550 are only ten airplanes apart on the production line. Any insight into this?

 

[kilo delta]

Yep..."550" above is registered as G-CBBL...those markings may be on her in tiny lettering somewhere, must take a closer look next time I'm at the field.

See the link in my post above Railrunner130.

Afaik, RAF serials are set aside in blocks/batches and the XX part of the serial is related to the year they were ordered? For example there are many BAe Hawks, Sepecat Jaguars and Aerospatiale Gazelles bearing the markings XX--- .

 

[Naki]

Railrunner ..off this web site http://www.ukserials.com/

"the U.K. is currently using a system of 2 letters followed by 3 digits that began in 1940 with AA100. Certain letters are generally not used as they look too similar to others, and some letter combinations are not used for a variety of reasons. The numeric part of the serial was traditionally between 100 and 999, but in recent years they have started at 001 in order to get more use out of the current system. "Blackout Blocks" were incorporated into all serial batches in order to disguise the true quantities of aircraft ordered or in service, but this practice has now ceased, however serial numbers are being allocated to even more simulators, again this is to allow maintenance records on these high-tech training devices to be kept up-to-date."

XX540 and XX550 are the military serials when they were first allocated to the RAF. On the above site checking XX540 and XX550 against the manufacturers serial number they were closely delivered together but not neccesairly ten aircraft apart as there would appear to have been an aircraft produced for another service in there.