Could have been a 109 check the foot print in the link
http://www.google.co.uk/imgres?imgurl=http://www.aviapress.com/engl/icm/icm72131_1.jpg&imgrefurl=http://www.aviapress.com/viewonekit.htm%3FICM-72131&usg=__SvMz5td8c_6iv-5oJ-9o53nnthg=&h=236&w=400&sz=16&hl=en&start=59&zoom=1&um=1&itbs=1&tbnid=cnNjgisEWPVjAM:&tbnh=73&tbnw=124&prev=/images%3Fq%3Dww2%2Bfighter%2Bme%2B109%26start%3D40%26um%3D1%26hl%3Den%26sa%3DN%26ndsp%3D20%26tbs%3Disch:1
If you are refering to the duo flying around yesterday, unfortunately, it was not a 109 !!! 
When you have been weaned on airfields and aircraft as I was with a RAF daddy, plus thousands of hours on Flight Sims, you get to recognise most aircraft from engine sounds alone.
If you are an aircraft buff, you will know that already. 
Where you are, Chris, like me, you must see a variety of types, out from White Waltham, Wycombe Air Park....and not least Heathrow.
Contra Rotating props were/are fitted to a number of long range aircraft, like the Fairey Gannet, and the outstanding maritime aircraft, the Avro Shackleton.
Once on patrol, these aircraft shut down one prop on the engine to maintain a longer range and time in the air.
Contra's on spits (PR) were for the same reason and also speed combined with the clipped wing 
You must be joking! In any case it was not possible to 'shut down' one propeller, they were linked by interconnector gears. I have 4000 hours on Shacks and we were grateful if the donks didn't stop on their own, without us encouraging them. Mk1's could certainly fly on one at very light weights, and certainly one would be feathered for training in assymetric flying, landings and overshoots. The last version, Mk 3 Phase three, was much heavier (Max AUW of 104,000lbs IIRC as opposed to about 86,000lbs of the Mk11's) It was fitted with two Viper jet engines running on Avgas in the nacelles of the outboard Griffons to assist on heavy take-offs. Unfortunately, at high AUW's in hot climates, it became necessary to use the Vipers in the cruise to maintain level flight, and consequently reduced range due high fuel consumption in this mode.
Your comment regarding shutting down engines to extend range did however apply to the Nimrod, and we used to shut down up to two engines as the weight reduced. I had an interesting engine failure just after shutting down the second engine on one occasion during a bombing run, and was impressed that with full power on the remaining Spey, our initial climb rate from 1000' amsl was 6000' per minute, with the bomb doors open adding drag. Quite a difference to the old Shacks!
Author
Topic: Spitfire and Mustang (?) over WIM (Read 3094 times)