need help on project

**SPIRIT** · 12th January 2009, 01:02 AM

I'm looking for help with a project l am doing with disengaged teenagers at high school

all the branches meet for a humane powered boat race at the end of the school year so far my school has had a DNF and a mid field ending

l ask you how hard is rowing

so this year I'm fitting a bikes to run a prop
The idea so far is remove the spokes from the rear wheel and bolt the gear that is near the pedals instead of the rim that way l can still use the gears on the 10 speed
then chain drive the rear shaft though a small bike gear ,then will run it though a diff (maybe one off a ride on mower )

now two questions what is a good prop for the speed that l can get my student make with this set up ??

2ND question but one more important how do you the rear gear off the hub ,there is a bearing on top ,no way of getting under it
had a test hit sitting the gear on the vice and hitting a nut washer thing inside the gear

worked out most of the other stuff if l cant get a mower diff free l may have to make one

hay is there a formula for gearing rpm= trust

may get the science class involved testing the beast

l may make it a wip if anybody is interested

simple boat plans would help

or ideas how to get more speed the thing is the whole job has to cost only 100$

**AlexS** · 12th January 2009, 07:58 AM

Can't help with much, but to remove the cluster (sprocket) from the hub you need small tool that fits into the slots in the middle of the cluster. There are a few varieties depending on the brand, so take it to your local bike shop.

**SPIRIT** · 12th January 2009, 12:18 PM

Originally Posted by AlexS

Can't help with much, but to remove the cluster (sprocket) from the hub you need small tool that fits into the slots in the middle of the cluster. There are a few varieties depending on the brand, so take it to your local bike shop.

thanks alex
l can make tools with the kids and teach them basic tool makeing ,can't see any slots do l have to remove the bearing first

**SPIRIT** · 12th January 2009, 02:59 PM

made tool to fit nut inside gear assembly question do you hold the gear or the wheel hub

**Cruzi** · 12th January 2009, 03:21 PM

Can't help with your questions, but a few thoughts

Humane powered is different to human powered

How about paddle wheels or wheel instead of a prop, much easier to fix than a prop.

Use a small diff to transfer power from bike to prop shaft.

Been watching to much Scrap heap challenge

**SPIRIT** · 12th January 2009, 05:40 PM

Originally Posted by Cruzi

Can't help with your questions, but a few thoughts

Humane powered is different to human powered

How about paddle wheels or wheel instead of a prop, much easier to fix than a prop.

Use a small diff to transfer power from bike to prop shaft.

Been watching to much Scrap heap challenge

one of the other teacher's team made a paddle wheel last year trying something different

got the larger gear fitted to back wheel hub

having trouble posting a photo

**SPIRIT** · 12th January 2009, 05:46 PM

new computers arrrrrrrrrrrrrrrrrr

**AlexS** · 12th January 2009, 06:49 PM

It appears you got the cluster off OK.

**SPIRIT** · 12th January 2009, 09:13 PM

Originally Posted by AlexS

It appears you got the cluster off OK.

got it going to see if l can get some old bikes tomorrow and off to see if l can find something to make a diff from

**echnidna** · 12th January 2009, 09:43 PM

I reckon you could use a bit of 3mm x 50mm flat.
Drill a hole in the centre of a suitable length to mount to a drive shaft.
Hold the flat in a metal vice over the hole, whack a 12" shifter on the end of the flat thats sticking up and twist the bar. Turn it over and do the same thing again.

I'd reckon that 150-200mm would be all thats needed.

I'd file all sharp edges and corners.

Its rough but its only going to spin slowly being pedal power so it should do

**SPIRIT** · 13th January 2009, 11:14 AM

Originally Posted by echnidna

I reckon you could use a bit of 3mm x 50mm flat.
Drill a hole in the centre of a suitable length to mount to a drive shaft.
Hold the flat in a metal vice over the hole, whack a 12" shifter on the end of the flat thats sticking up and twist the bar. Turn it over and do the same thing again.

I'd reckon that 150-200mm would be all thats needed.

I'd file all sharp edges and corners.

Its rough but its only going to spin slowly being pedal power so it should do

thanks

will make one like that
thinking l will rig up a test bath so l can measure the force some how

then we can keep making props and gears and make a graph of the out comes

would 10mm drive shaft be ok to use then l can use axles from the front wheels or is it to thin

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