Out with the angle grinder.
Random Orbit version 1 had a 750mm duct and putting 45bhp through that is a bit of a tall order and so I decided to put a bigger duct on. I’d also heard that some time earlier, someone had put a lift duct on a Cyclone and raced it in F1.
I decided I’d have a go at putting a 900mm thrust fan and a lift fan on Random Orbit.
The rules in F3 say that you can run any number of two-stroke engines in any combination up to a maximuim of 250cc but it’s tricky finding a good combination to give lift and thrust so I decided to try a shaft drive.
[note. I’m writing this in 2008 and shaft drive craft are all over the place but when I did this job in 2001ish they were quite rare]
A shaft drive means you can get the advantages of twin ducts on a single engined craft but designing one does make things interesting.
A big note… I didn’t take nearly enough photos and without them it all seems a bit dry so this section is very short.