Fokker G-1 video
 

I've just stumbled upon this very interesting video:

Nice find Simon, thanks for sharing :ok: it's very interesting as you say!

Quite spirited handling by Karel Mares at a fairly early stage in its career!

I note from the video, that the originally fitted Hispano-Suiza 14AB-02/03 engines were set up to run as counter-rotating pairs (I think that's what the suffix 02/03 means :8), whereas, the in-service photos show the replacement Wasp or Mercury units running in the same direction.

Yes, early Breguet 690s had the same pair of engines with C/R props, presumably achieved in the gearbox rather than having the crankshafts rotating in opposite directions.

As a general rule, H-S engines had even-numbered suffixes, any that had odd numbers drove C/R props.

“Kelly” Johnsons inspiration (said jokingly) for the P-38? Except for the tail wheel of course. Kelly even copied the engine rotation on his prototype.

I seem to recall from a book about the P-38 that they had to swap the engines to change the direction of the propwash, which was causing handling difficulties - stability during gunnery?

Looking at the G-1 video again, I see there was only one-tailwheel, in the middle of the tailplane. That must have required considerable beefing up of the structure. I wonder if the weight penalty was worth it.

Wasnt it the brits who changed the direction of the prop's on the P-38?
Anyhow, counter rotating propellars are rare to find but one of few the twin engined a/c's with counter rotating propellars: The OV-O1 Bronco, is with it's twin boom design much like the P-38 :-/

Yes, it all had to do with the power on/power off change in pitching moment. The rotation finally settled on produced the least change, and so made for a better gun platform. The original prototype direction was the worse, with the British set up in between.The British had both engines rotating in the same direction, as they wanted commonality with the P-40. Not used in combat and most saw their life out as trainers in the US with the USAAF.

Looks more like Northrop's P-61 Black Widow. 'specially the glassed in area at the back.

The Black Widow had radial engines too.

Anil