First made a push stick for in-line skating...

https://farm6.staticflickr.com/5270/...79e62d61_z.jpg

Got a little real-world use out of it. It was fun. Eventually the right
angle gear broke from normal wear and tear. Having no support on the other
side of the wheel, that was no surprise.

That did not take advantage of a clutch, mainly because there is no
clutch on DeWalt's right angle drill. Stopped skating. Started cycling.
Now I get to take advantage of all the cool stuff that a cordless drill
includes, including the clutch...

https://farm4.staticflickr.com/3681/...deaab67a_c.jpg

https://farm1.staticflickr.com/538/1...d07dec60_c.jpg

Apparently the drivetrain has loosened up a bit. Using the highest
clutch setting (before drilling) worked fine for going up slight hills
today. The clutch only slipped once, when I was at a stop and
accidentally slapped down on the throttle. Worked just like it's
supposed to.

Bought some aluminum and plastic suitable for rebuilding the sprockets
without wood. I might try to eliminate all the wood in the structure,
but wood is useful for making unplanned additions. Or maybe I will try
using thick PVC slabs. It's lighter than aluminum.

Also want to upgrade the drill to one that includes a soft start
feature. The soft start sounds cool for more smoothly powering a
bicycle. It might not be necessary, but I'm sure it's better.

Took it out in sunny afternoon 98°F weather for a 6 mile trip. The 20V
5AH battery shows one out of three bars remaining. Drill got hot but
there was no performance change.






First made a push stick for in-line skating...

https://farm6.staticflickr.com/5270/...79e62d61_z.jpg

Got a little real-world use out of it. It was fun. Eventually the
right angle gear broke from normal wear and tear. Having no support on
the other side of the wheel, that was no surprise.

That did not take advantage of a clutch, mainly because there is no
clutch on DeWalt's right angle drill. Stopped skating. Started
cycling. Now I get to take advantage of all the cool stuff that a
cordless drill includes, including the clutch...

https://farm4.staticflickr.com/3681/...deaab67a_c.jpg

https://farm1.staticflickr.com/538/1...d07dec60_c.jpg

Apparently the drivetrain has loosened up a bit. Using the highest
clutch setting (before drilling) worked fine for going up slight hills
today. The clutch only slipped once, when I was at a stop and
accidentally slapped down on the throttle. Worked just like it's
supposed to.

Bought some aluminum and plastic suitable for rebuilding the sprockets
without wood. I might try to eliminate all the wood in the structure,
but wood is useful for making unplanned additions. Or maybe I will try
using thick PVC slabs. It's lighter than aluminum.

Also want to upgrade the drill to one that includes a soft start
feature. The soft start sounds cool for more smoothly powering a
bicycle. It might not be necessary, but I'm sure it's better.

On Wed, 29 Jul 2015 23:24:58 +0000 (UTC), John Doe
wrote:

Took it out in sunny afternoon 98°F weather for a 6 mile trip. The 20V
5AH battery shows one out of three bars remaining. Drill got hot but
there was no performance change.

This is really interesting, but I'm having trouble with some of the
numbers. Say the "two bars" consumption equals, roughly, 3 A-hr. At 20
volts, we have 60 W-hr. Just guessing here, but say you travelled that
6 miles at 12 mph.

That means the drill was drawing an average of 120 W for a half-hour.
Let's be generous and say that the system efficiency is 80% from
storage to power at the drill shaft. So, given chain and friction
losses at the tire, you have 1/8 hp driving the bike.

Will that be enough to move you at 12 mph? I'm not familiar with the
actual power consumed by these bikes, but that sounds low. Am I
missing something?

--
Ed Huntress






First made a push stick for in-line skating...

https://farm6.staticflickr.com/5270/...79e62d61_z.jpg

Got a little real-world use out of it. It was fun. Eventually the
right angle gear broke from normal wear and tear. Having no support on
the other side of the wheel, that was no surprise.

That did not take advantage of a clutch, mainly because there is no
clutch on DeWalt's right angle drill. Stopped skating. Started
cycling. Now I get to take advantage of all the cool stuff that a
cordless drill includes, including the clutch...

https://farm4.staticflickr.com/3681/...deaab67a_c.jpg

https://farm1.staticflickr.com/538/1...d07dec60_c.jpg

Apparently the drivetrain has loosened up a bit. Using the highest
clutch setting (before drilling) worked fine for going up slight hills
today. The clutch only slipped once, when I was at a stop and
accidentally slapped down on the throttle. Worked just like it's
supposed to.

Bought some aluminum and plastic suitable for rebuilding the sprockets
without wood. I might try to eliminate all the wood in the structure,
but wood is useful for making unplanned additions. Or maybe I will try
using thick PVC slabs. It's lighter than aluminum.

Also want to upgrade the drill to one that includes a soft start
feature. The soft start sounds cool for more smoothly powering a
bicycle. It might not be necessary, but I'm sure it's better.

Ed Huntress wrote:
On Wed, 29 Jul 2015 23:24:58 +0000 (UTC), John Doe
wrote:

Took it out in sunny afternoon 98°F weather for a 6 mile trip. The 20V
5AH battery shows one out of three bars remaining. Drill got hot but
there was no performance change.

This is really interesting, but I'm having trouble with some of the
numbers. Say the "two bars" consumption equals, roughly, 3 A-hr. At 20
volts, we have 60 W-hr. Just guessing here, but say you travelled that
6 miles at 12 mph.

That means the drill was drawing an average of 120 W for a half-hour.
Let's be generous and say that the system efficiency is 80% from
storage to power at the drill shaft. So, given chain and friction
losses at the tire, you have 1/8 hp driving the bike.

Will that be enough to move you at 12 mph? I'm not familiar with the
actual power consumed by these bikes, but that sounds low. Am I
missing something?


Well consider also that the bars may not be an accurate indicator of the
state of charge.

Leon wrote:

Ed Huntress wrote:
John Doe wrote:

Took it out in sunny afternoon 98°F weather for a 6 mile trip. The
20V 5AH battery shows one out of three bars remaining. Drill got hot
but there was no performance change.

This is really interesting, but I'm having trouble with some of the
numbers. Say the "two bars" consumption equals, roughly, 3 A-hr. At
20 volts, we have 60 W-hr. Just guessing here, but say you travelled
that 6 miles at 12 mph.

That means the drill was drawing an average of 120 W for a half-hour.
Let's be generous and say that the system efficiency is 80% from
storage to power at the drill shaft. So, given chain and friction
losses at the tire, you have 1/8 hp driving the bike.

Will that be enough to move you at 12 mph? I'm not familiar with the
actual power consumed by these bikes, but that sounds low. Am I
missing something?

Well consider also that the bars may not be an accurate indicator of
the state of charge.

For sure.

Since I didn't take the spare battery, as much as possible of the trip
was coasting. And I was trying to make sure the thing didn't overheat,
using full throttle (probably less than 12 mph) whenever possible so the
switch would bypass itself. The more powerful/capable drill will
probably be more fun and less worry in 98° late afternoon heat.

It was a strange trip using an unfamiliar mode of transportation.
Definitely not fast enough to be on the street when there is any traffic.
But the sidewalks are broken up and it's not a dirt bike. I hope to be
better prepared for rough terrain in the next planned version.

There are some cool possibilities to do with gearing. My next (planned)
drill low gear goes up to only 450 RPM. Some common freewheel cassettes go
up to 34 teeth. That probably means a 12 or 14 tooth front sprocket will
be powerful enough for the steepest hills around here (perhaps 15°, I
dunno). Keeping the rear sprockets, derailer, and shifter in place, it can
be quickly and easily shifted into a smaller/higher gear for greater
speed. Probably using no more than one or two other of the cogs, but it's
much quicker and easier than stopping to switch the drill speed range.

On Thu, 30 Jul 2015 06:11:27 +0000 (UTC), John Doe
wrote:

Leon wrote:

Ed Huntress wrote:
John Doe wrote:

Took it out in sunny afternoon 98°F weather for a 6 mile trip. The
20V 5AH battery shows one out of three bars remaining. Drill got hot
but there was no performance change.

This is really interesting, but I'm having trouble with some of the
numbers. Say the "two bars" consumption equals, roughly, 3 A-hr. At
20 volts, we have 60 W-hr. Just guessing here, but say you travelled
that 6 miles at 12 mph.

That means the drill was drawing an average of 120 W for a half-hour.
Let's be generous and say that the system efficiency is 80% from
storage to power at the drill shaft. So, given chain and friction
losses at the tire, you have 1/8 hp driving the bike.

Will that be enough to move you at 12 mph? I'm not familiar with the
actual power consumed by these bikes, but that sounds low. Am I
missing something?

Well consider also that the bars may not be an accurate indicator of
the state of charge.

For sure.

Since I didn't take the spare battery, as much as possible of the trip
was coasting. And I was trying to make sure the thing didn't overheat,
using full throttle (probably less than 12 mph) whenever possible so the
switch would bypass itself. The more powerful/capable drill will
probably be more fun and less worry in 98° late afternoon heat.

It was a strange trip using an unfamiliar mode of transportation.
Definitely not fast enough to be on the street when there is any traffic.
But the sidewalks are broken up and it's not a dirt bike. I hope to be
better prepared for rough terrain in the next planned version.

There are some cool possibilities to do with gearing. My next (planned)
drill low gear goes up to only 450 RPM. Some common freewheel cassettes go
up to 34 teeth. That probably means a 12 or 14 tooth front sprocket will
be powerful enough for the steepest hills around here (perhaps 15°, I
dunno). Keeping the rear sprockets, derailer, and shifter in place, it can
be quickly and easily shifted into a smaller/higher gear for greater
speed. Probably using no more than one or two other of the cogs, but it's
much quicker and easier than stopping to switch the drill speed range.

I looked up some energy research data on bicycles and it looks like
you can get just about 12 mph with 100 - 120W. So you're right in
there.

--
Ed Huntress

http://www.mongoose.com/usa/fireball-350

Almost precisely what I was looking for my next attempt.

Aluminum frame on a 20 inch bike, should be light.

V-brakes back and front. Good stopping power.

One piece front fork. If it had shocks, they would bottom out. Ideally, it
might have some suspension, but I have an exceptionally springy and
comfortable aftermarket cruiser saddle (Serfas FS-CR).

Rear derailer with sprockets up to 28 teeth. Probably can be upgraded to
34 teeth if necessary.

Apparently the chain is 3/32 inch and the bottom bracket is a standard
bicycle square taper type (the latter being a big bonus over a BMX bike,
for my purpose).

Thirty-six spokes for decent strength. Many have only 32. Ideally could be
double walled rims, I guess.

Ideally, the tires would be street tires but at least they aren't full out
knobby.

Besides not having suspension (that would make it more complex/expensive),
not having street tires is the only real drawback. But of course tires
eventually get replaced.

The fact that it's small with 20 inch wheels isn't such a big deal since I
won't be peddling. Most electric scooters have smaller wheels than that.