104 mph self peddled bicycle

thine82 said:

guys if you do the math.. 44 teeth to elven teeth times four and and the wheel... wheel it comes out to being that quickly.. who is to say that it wouldnt work?

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Allright then, lets do the math.
44-11 = 4x multiplcation....lets crank to full cadence of 90 rpms.
Wheel use a 20" bicycle wheel for the gearing advantage of smaller wheels

Stage1 (90 x 4 = 360)-21.6MPH
stage2 (x 4 =1440 )(you are now traveling at 86.4 mph on a 20" bicycle)
Stage3 (x4 =5760rpms)....you are beyond 345 mph..stage 1 chain is past breaking point by 12x..
you need 676 HP to maintain this speed in perfect conditions.
stage4 (x4=23040 rpms) you have broken the sound barrier at 1382 mph.

As has been said, the math is the easy part.

Who's to say it wouldn't work? no one....unless you plan to use a human for power. Here are some more #s to put in the hat

We wont account for drive train losses or any wind. upright bike with aero bars on it.
17mph=9 newtons of drag, power consumption=75 watts (.1 HP)
(average human power output)
25mph=18 newtons drag, power consumption=207 watts (.3 hp)
34mph=33 newtons drag, PC=503 watts (.7 hp)
notice the drag is increasing by the sqrt of velocity....

Again Not trying to be Negative...just realistic & speaking from experiance regarding machinery design & power requirments to do the things your talking about.
Here is a far more realistic senario..with a single Jackshaft.
44 to 14 then a 30 to 11 on the rear wheel.

That has the potential of 46 ish mph at a 90 cadence using 20" wheels again.
Build that & see how fast you can pedal it.

Its a lot of fun to run the #s & dream. We are just trying to keep you from wasting any time attempting to bite off more than any human can chew.
I am not a power train engineer.. I am a wood worker with an areodynamics hobby.
Enjoy..

When I was a little kid, similar ideas would swim in my head that Thine has.

Actually had a board track bike that my dad got for me (dad was a little nuts).
Had no brakes, used wood rims with small expensive tires and one gear (real tall ratio). Took a lot for a kid in second grade to get going.
This bike was state of the art a hundred years ago.
The bike disappeared when I cut the very tips of my fingers off cleaning the chain.

Anyway- Thine- go get a road bike, leave it in the highest gear and go for a ride.
See how many cars you can pass. Please get back to us.
Thanks for the humor though.

well i say if someone can peddle a bike to 82 mph and get a 50cc to go 150 mph, then why cant this idea work? im sure there are some mathematical errors with it now, but that's what trial and error is for. if everyone listened to the "impossible" statements, this world would be pretty damn primitive. and im assuming that 104 is an end goal, but the main point is a lot of speed with less effort thanks to advanced gearing. it is definately not a waste of time

"lot of speed with less effort"? Where's the added power coming from? The faster the speed, the more power is required - exponentially.

It's not that folks are nay saying just for the sake of remaining "primitive" or to shoot down ideas - it's that an incredibly critical factor is so often left out of armchair engineering sessions;

With a doubling of speed the drag (force) quadruples per the formula. Exerting four times the force over a fixed distance produces four times as much work. At twice the speed the work is done twice as fast. Since power is the rate of doing work, four times the work done in half the time requires eight times the power.

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http://en.wikipedia.org/wiki/Drag_(physics)

They made a tv series about it.The guy was riding his pedal bike one day at high speed and blew a tire by hitting a small pothole,The bike proceded to basicly discinergrate but he lived through it,and they had the technology and rebuilt him,thus Steve Austin "Six Million Dollar Man"came into being that day many years ago(They just used the expermintal plane crash in the trailer 'cause they didn't think anyone would believe a bike crash would grab the audience attention )




lol

I need Six million dollars

Wind resistance is why you'll never reach the target speed without a big motor or big hill.

The first rider to break 60 mph peddling was following a train and "drafting" the train.

All recent bicycle speed records for peddling have involved following a streamliner car on the Bonneville Salt Flats (or similar area).

corgi1 said:

I think Lee Majors or the green guy (Hulk) might be able to do it, otherwise maybe motor assist and leg power,,, Lance and his buddies are probibly good for 55 and I think I have heahd talk of short 120 cadence burst of pedeling

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A couple of years ago when I was in good shape I could hit 120 rpm in low gears for several seconds on my recumbent. Couldn't keep it up for long though and HAD to have clipless pedals.

KevXR said:

Wind resistance is why you'll never reach the target speed without a big motor or big hill.

The first rider to break 60 mph peddling was following a train and "drafting" the train.

All recent bicycle speed records for peddling have involved following a streamliner car on the Bonneville Salt Flats (or similar area).

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he probibly could have gone faster if the train was gaining speed and following him,lol
RR ties are hard to walk on it would be a rough chore peddleing on them

corgi1 said:

he probibly could have gone faster if the train was gaining speed and following him,lol
RR ties are hard to walk on it would be a rough chore peddleing on them

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Fortunately, he was smarter than other people... over 100 years ago.

Or he could have built a nice "rail bike".

Cycling records - Wikipedia, the free encyclopedia

History of motor-paced records
Motor pacing is a type of human powered record where a pace vehicle is modified by adding a tail fairing to keep the wind off the cyclist who is riding behind it. This type of record was invented by Charles “Mile-a-Minute Murphy” who drafted a train to set a 96 km/h (60 mph) record at end of the 19th century. A mile of plywood sheets was attached to the railroad ties, so Charles would have a smooth surface riding behind the train[8][9].

Here is a webpage with speed records.

You may need to translate to English.
LOS TAJAS: VOLANDO BAJO

duffmandied said:

well i say if someone can peddle a bike to 82 mph and get a 50cc to go 150 mph

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Well sure, sitting still on a dyno, I'd wager Bad Mojo's 66cc and NuVinci hub would easily do 65 on a dyno.

My point is, do you have any idea how strong a 100 MPH wind is?

The next time you have a REALLY windy day, like 40+MPH winds, go pedal or motor into it and do the math.
Even easier, hang out of the car window going 75.

It is one thing to spin something sitting still 100 MPH, quite another to combat 100MPH wind.

The 50 cc bike had about 25 turboed HP and very low drag due to streamling in a recumbent position and still took many miles to reach that speed after changing through at least six gears......going from memory so some of those numbers may be off a bit. I would say that the powerband was extremely narrow.
All in all, not much good as a daily rider lol

The "pedal bike" also used a very efficient streamlined body and it looked nothing like a bicycle. The rider could barely walk after he finished.

It's pretty basic math and trial and error doesn't have much to do with it.

also these recumbent streamliners are not very practical and are very suceptible to side winds. IE: They blow over real easy....

duffmandied said:

well i say if someone can peddle a bike to 82 mph and get a 50cc to go 150 mph, then why cant this idea work? im sure there are some mathematical errors with it now, but that's what trial and error is for. if everyone listened to the "impossible" statements, this world would be pretty damn primitive. and im assuming that 104 is an end goal, but the main point is a lot of speed with less effort thanks to advanced gearing. it is definately not a waste of time

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If you have a helicopter, you might get a peddal powered bike up to the speed you want.

Here a VW beats a Porsche

http://www.youtube.com/watch?v=SiAbcw5s9_8

(The dropped the VW from a helicopter.)

I don't want to discourage you but your crazy!
Yeah and I've divised a way to make a car go 1000 mph with a few gears!!!

I don't want to discourage him either. And I do really think this can be done. But a few things have become self evident:

It will take a lot of TIME to get a pedal powered bike up to 104 mph. How much time depends on other variables.

It will take a lot of GEARS to get it up to that speed.

It will take a heck of a lot of STREAMLINING, flawless streamling, a rock-bottom coefficient of drag, to even get near that speed.

And it will take a lot of MONEY to get the above. And I sincerely hope he does have enough money, because I really would like to see a pedal powered bike set that kind of record.