What's the fastest recorded speed you've achieved without the use of an engine?

[IR35FanClub]

Mine is 56 mph on the water slide at Disney in Orlando. Unluckily I was wearing speedos and had to remove them with pliers. Had I been wearing boxer shorts I'd have probably only hit 49. I used the speed style... cross legs on one heel, raise bum, rest on shoulder blades. Then covered my face with my hands, not because I was scared of the initial vertical drop - it was so I can breathe when hitting the water trap.

[Zippy]

About 40mph

[SimonMac]

About 28mph

What's the Average Speed of Male Ejaculation?

[EternalOptimist]

about 60 mph.

I came down the tiger slope at glenshee on me bum, having lost my skis at the top due to a newbie error.
a man on his bum, lubricated by a thin coating poo, can outstrip an olympic speed skier, and I proved it.

luckily there was a sturdy fence at the bottom else I would be well on my way to Antarctica by now

[NotAllThere]

60mph - but in control, on my skis.

[kingcook]

17mph, raising to 21mph briefly at the vinegar stroke.

[Old Hack]

56 mph downhill on the A38 on a PlanetX carbon bike, and about 55-60mph flying through the air on the way to breaking both legs in Gressoney la Trinite whilst attempting to show people how good I was at going fast on snow. 1991.

[MarillionFan]

35mph downhill from Salisbury Plain to the White Horse on a mountain bike with thick offroad tyres.

[Mich the Tester]

About 45mph, last week at the Apeldoorn velodrome, dropping off the banking onto the straight. Didn't keep up that speed for long though.

[Malcolm Buggeridge]

I should imagine that any practitioner of free fall skydiving would regularly achieve the terminal velocity of 125mph.

Not that I've ever done it mind you. Gives me sweaty palms just watching those chaps.