33 replies to this topic

[Magoo]

What could possibly go wrong.

 

A hydrogen peroxide rocket motor on a bicycle. With 1000 lbs (claimed) thrust. Watch it go 207 mph in 250 meters. Listen to the wheel bearings make funny noises on coast down. 

 

 

 

Video: Rocket bicycle runs 207 mph, leaves Ferraris in the dust | Mac's Motor City Garage.com

 

 

 

[imaginesix]

1.96G if my math is right?

That elusive 2G-on-a-bicycle barrier remains unbroken.

[Fat Boy]

Well, that looks pretty frisky. Darwin will only be cheated for so long...

[munks]

1.96G if my math is right?

 

Sure, for the *average*.

[Bloggsworth]

As pointless exercises go, this one takes the biscuit...

[BRG]

I think it's a great idea.  If they used a different sort of propulsion unit, say a small internal combustion engine, it could become quite practical.  They could call it...I don't know, maybe, a motor-cycle?

[desmo]

But then it'd be too slow.

[Fat Boy]

1 thought for the bike-centric...Strava KOM's.

[imaginesix]

As pointless exercises go, this one takes the biscuit...

Hahahaha no, not even close.

I give you... Colin Furze

http://www.youtube.c...h?v=EorMrpM6q9Q

[Canuck]

My introduction to that stunt was via text message from a fellow cyclist - well there goes all my KOMs... That said it appears to have cost him a lot of hair.

[Lee Nicolle]

They had better go run it in top bike at the drags. Though maybe the 'tech' may find fault with a 40mph chassis and brakes at 200mph.

Though to be fair it looks more stable than most of those Top Bikes

[desmo]

The scariest part for me, like it is when I see a lot of LSR stuff, is the tires. Those look like actual bicycle tires, where I'd expect to see something like the tires used on 50 or 125cc road racing motorcycles fitted.

[just me again]

Hahahaha no, not even close.

I give you... Colin Furze

http://www.youtube.c...h?v=EorMrpM6q9Q

 

And he have also run a jet bike. With minimal cost and safety gear

 

https://www.youtube....PAuRe38kvcQ9_V7

 

 

 

https://www.youtube....h?v=bKHz7wOjb9w

[Kelpiecross]

I thought this was very interesting (and surprising) - this could be a useful and fairly simple technique for making things apart from pulse jets.

This bloke is not as silly as he appears to be.

[BRG]

Hahahaha no, not even close.

I give you... Colin Furze

http://www.youtube.c...h?v=EorMrpM6q9Q

This guy makes Jeremy Clarkson look like a Health and Safety Inspector!  Makes you proud to be British - we can still produce complete loonies to match the best.

[Ross Stonefeld]

1 thought for the bike-centric...Strava KOM's.

 

http://drunkcyclist....rava-terrorism/

[saudoso]

Well, that looks pretty frisky. Darwin will only be cheated for so long...

Hugging a rocket engine with your legs. Way to go...

[Lee Nicolle]

The scariest part for me, like it is when I see a lot of LSR stuff, is the tires. Those look like actual bicycle tires, where I'd expect to see something like the tires used on 50 or 125cc road racing motorcycles fitted.

My comments on 40mph chassis includes the tyres. Bloody bicycle tyres. Though it is a bicycle! Just going 5 times faster than it is designed to do. And they actually do that quite poorly. At 40mph the brakes are near useless, the traction to turn is little better and they wobble when pedalled!

Just put a jet on it will solve that problem!

[BRG]

My comments on 40mph chassis includes the tyres. Bloody bicycle tyres. Though it is a bicycle! Just going 5 times faster than it is designed to do. And they actually do that quite poorly. At 40mph the brakes are near useless, the traction to turn is little better and they wobble when pedalled!

Watch pro cycle racers descending on a mountain road.  They can hit 50mph and often the TV motorbikes can barely keep up, especially round the corners.

[desmo]

Yes, bicycles can corner pretty quick. Road racing bicycle tires are far from optimized for cornering too, they are too narrow, high pressure and low volume. If cost were no object, FMB would make you a slick on their fat touring carcass tubular, or I expect you could even find an off the shelf speed biased 650B that would get you most of the way there.

<edit> OK, it's hard to find much in the way of technical info on the rocket bike, but I found a link here that explains, "The tires, however, are made for speed. They were tested by Michelin to 300 km/h for one hour with 100 kg load on each tire." So basically with no tractive or significant braking demands or hopefully... hopefully, any cornering demands. All you ask of the tire here is for it to work and not fail.

[Canuck]

Guy pilots bicycle to 207 mph, F1 tech forum goes "oh, that's so dangerous".
Thanks for the laugh.

[Lee Nicolle]

Yes, bicycles can corner pretty quick. Road racing bicycle tires are far from optimized for cornering too, they are too narrow, high pressure and low volume. If cost were no object, FMB would make you a slick on their fat touring carcass tubular, or I expect you could even find an off the shelf speed biased 650B that would get you most of the way there.

<edit> OK, it's hard to find much in the way of technical info on the rocket bike, but I found a link here that explains, "The tires, however, are made for speed. They were tested by Michelin to 300 km/h for one hour with 100 kg load on each tire." So basically with no tractive or significant braking demands or hopefully... hopefully, any cornering demands. All you ask of the tire here is for it to work and not fail.

I doubt the rims were however. 

[Catalina Park]

I doubt the rims were however.

So what did they mount the tyres on when they were testing them to 300 kph then?

[Lee Nicolle]

So what did they mount the tyres on when they were testing them to 300 kph then?

Bicycle wheels I guess. Unless they have changed  [possibly in 40+ years] a small ball bearing hub and as is obvious  for the runs an alloy rim and spokes.  Though the 2 bikes here are equipped such. Sounds very scarey too me. 

I simple tapered roller is more stable at high speeds though can you get them that small? Lubricant too would be a real issue, especially on those little ball bearings. Though tiny tapered bearings are probably the same issue

When I was a kid delivering papers over a long route I regularly had to replace the balls and retrue the [steel] rims as the spokes loosened from the load of a 150 20 page papers.

[Catalina Park]

I was working on a proper competition BMX wheel the other day and I was amazed at the quality and strength in the hub, axle and bearings. 

Nothing like the stuff we used to play with. This was seriously heavy duty.

[Catalina Park]

Mind you the spokes were all loose!

[gruntguru]

Very sensible of him to retain the pedals - the rocket doesn't seem suitable for getting to and from the track.

Edited by gruntguru, 18 November 2014 - 00:22.

[Kelpiecross]

Slightly beside the point - but I am often surprised by just how small in diameter, narrow and flimsy-looking are the front tyres on a Top Fuel dragster - and they go well over 300MPH. Some examples appear to be only about one foot in diameter.

[gruntguru]

Interestingly the hoop stress is independent of the wheel diameter.

[Lee Nicolle]

Slightly beside the point - but I am often surprised by just how small in diameter, narrow and flimsy-looking are the front tyres on a Top Fuel dragster - and they go well over 300MPH. Some examples appear to be only about one foot in diameter.

Bud wheels I believe they are called. Dont seem to be around any more. Though they would slow down the bearing speed and they were wider tyres.

Drag racers often do not make sense! Very skinny front tyres are not real clever. Skinny yes, just not so skinny. They would crash less with more rubber at the front when they get sideways. A wider front track would help too though that would drag more air.

[Canuck]

That presumes that there is weight on the front wheels which seems counter to everything I've ever seen in a top fuel car rail.

[imaginesix]

Well, the steering has to be connected to something, so there must be at least a little weight on the front sometimes.

[DavidI]

Top fuellers spend so little time with their front wheels on the ground that having wider rubber is unnecessary. Interestingly most of the steering is aerodynamic - consider the sort of speed they attain and the idea of the front wheels acting as rudders starts to make some sort of sense.

[gruntguru]

They would crash less with more rubber at the front when they get sideways.

Since when is more front grip a solution to oversteer?