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

[gingerjedi]

Around 45mph in a small production class land yacht, the record for mini yachts is 64.4mph.

You can travel at double the wind speed up to about 35mph but above that the ratio decreases the faster you go.

[Robinho]

60 knots, glide landing in a Cessna 152.

[rhubarb]

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.

Yep, would have achieved this during my VERY brief stint of learning to skydive.
Lesson 1. Slight hesitation in the doorway as I considered NOT jumping out the plane.
Did jump.
All went really well until I neared the ground. I ended up floating about 20 feet above the same plane I'd jumped out of a few minutes earlier as it taxied along the ground. Scared the life out of me.
So that was that.
Stupid "sport".

[NotAllThere]

Felix - Mach 1.2

[IR35FanClub]

Around 45mph in a small production class land yacht, the record for mini yachts is 64.4mph.

You can travel at double the wind speed up to about 35mph but above that the ratio decreases the faster you go.

I never did get this? Yould think the fastest you could go would be as fast as the wind - else the sail will act as a big airbrake. That's why I gave up maths post A Level. I guess you aren't sailing with the wind directly behind - maybe across it, and then just using the force of the wind on the sail in some variation of f=ma. i.e a=f/m. As the speed increases the force drops and therefore acceleration becomes zero.

[gingerjedi]

I never did get this? Yould think the fastest you could go would be as fast as the wind - else the sail will act as a big airbrake. That's why I gave up maths post A Level. I guess you aren't sailing with the wind directly behind - maybe across it, and then just using the force of the wind on the sail in some variation of f=ma. i.e a=f/m. As the speed increases the force drops and therefore acceleration becomes zero.

Yep, you travel faster sailing at around 90 degrees to true wind and as you speed up you have to take 'apparent' wind into account and streamline the sail. It helps to think of it as a foil rather than a sail.



Travelling faster than the wind is a lot easier on wheels (ice is even faster) as you don't have to contend with the resistance created by water.

You can't travel downwind faster though... unless you're this guy:

[realityhack]

About 90mph, during a ~300ft bungee jump.
55mph on the bike.
About 30mph on inline skates down a very steep hill - a VERY stupid thing to do.