This is my most recent push stick for inline skating. It works OK but
it is still being improved.

http://farm9.staticflickr.com/8524/8...3e921320_z.jpg

In the bottom right, there is a yellow gearbox.

Between that gearbox and the crankshaft inside of the orange body,
there is a 1/4 inch aluminum rod connecting the two.

Being a two cycle engine, there is some sputtering. The wheel bounces
back and forth as it turns and the gears get banged around a lot. I'm
afraid that's going to eventually break stuff.

The 1/4 inch aluminum drive rod is about 8 inches long. I would like
to replace it with something flexible, or put a clutch in there.
Anything that would absorb some shock. I suppose a clutch would have
to be at the gearbox output, since the motor spins the rod at
thousands of RPMs.

Any easy possibilities?

How about a smaller diameter 8 inch rod of spring steel? I don't know
if spring steel works that way, just asking.

Or perhaps the amount of stress when it's banging around at idle is
no greater than the more uniform stress when it's pushing me up a
hill. I could just wait and repair it as needed. I'm definitely going
to continue testing it as is.

Thanks.

On Mon, 17 Jun 2013 17:56:54 +0000, John Doe wrote:

This is my most recent push stick for inline skating. It works OK but
it is still being improved.
http://farm9.staticflickr.com/8524/8673965338_3b3e921320_z.jpg
In the bottom right, there is a yellow gearbox.

Between that gearbox and the crankshaft inside of the orange body,
there is a 1/4 inch aluminum rod connecting the two.

Being a two cycle engine, there is some sputtering. The wheel bounces
back and forth as it turns and the gears get banged around a lot. I'm
afraid that's going to eventually break stuff.

The 1/4 inch aluminum drive rod is about 8 inches long. I would like
to replace it with something flexible, or put a clutch in there.
Anything that would absorb some shock. I suppose a clutch would have
to be at the gearbox output, since the motor spins the rod at
thousands of RPMs.
[snip]

How much room do you have for whatever would replace the 8" x 1/4" rod?

A freewheel (a ratchet mechanism as used with a bicycle's rear gearset)
might handle the problem better than a clutch.

--
jiw

Google flexplate. Some vehicles used one made of rubberized fabric between
the steering wheel and the steering gear box. My big CNC mill uses one
between the X axis motor and the X axis drive screw made of stacked thin
pieces of stainless spring steel sheet.

Depending on your shop capabilities you could make your own.





"John Doe" wrote in message
...
This is my most recent push stick for inline skating. It works OK but
it is still being improved.

http://farm9.staticflickr.com/8524/8...3e921320_z.jpg

In the bottom right, there is a yellow gearbox.

Between that gearbox and the crankshaft inside of the orange body,
there is a 1/4 inch aluminum rod connecting the two.

Being a two cycle engine, there is some sputtering. The wheel bounces
back and forth as it turns and the gears get banged around a lot. I'm
afraid that's going to eventually break stuff.

The 1/4 inch aluminum drive rod is about 8 inches long. I would like
to replace it with something flexible, or put a clutch in there.
Anything that would absorb some shock. I suppose a clutch would have
to be at the gearbox output, since the motor spins the rod at
thousands of RPMs.

Any easy possibilities?

How about a smaller diameter 8 inch rod of spring steel? I don't know
if spring steel works that way, just asking.

Or perhaps the amount of stress when it's banging around at idle is
no greater than the more uniform stress when it's pushing me up a
hill. I could just wait and repair it as needed. I'm definitely going
to continue testing it as is.

Thanks.

On 6/17/2013 11:43 AM, Bob La Londe wrote:
Google flexplate. Some vehicles used one made of rubberized fabric
between the steering wheel and the steering gear box. My big CNC mill
uses one between the X axis motor and the X axis drive screw made of
stacked thin pieces of stainless spring steel sheet.

Depending on your shop capabilities you could make your own.


My 1983 Mercedes 300 SD uses at least one flex plate in the drive line.
Handles lots of torque for lots of years! It's metal, I am sure.

I have seen small flex plates used in electronic equipment to allow for
slight misalignment of control shafts. 1/4 inch shaft, etc.

Paul

On Mon, 17 Jun 2013 13:55:52 -0700, Paul Drahn
wrote:

On 6/17/2013 11:43 AM, Bob La Londe wrote:
Google flexplate. Some vehicles used one made of rubberized fabric
between the steering wheel and the steering gear box. My big CNC mill
uses one between the X axis motor and the X axis drive screw made of
stacked thin pieces of stainless spring steel sheet.

Depending on your shop capabilities you could make your own.


My 1983 Mercedes 300 SD uses at least one flex plate in the drive line.
Handles lots of torque for lots of years! It's metal, I am sure.

some of the BMWs have these in the drive train- rubber and cord.
It goes between the transmission and the first drive shaft (RWD).

http://www.oembimmerparts.com/produc...FVKf4AodgwIAfA


Apparently they look like this when they're done:

http://i253.photobucket.com/albums/h...s/IMG_1156.jpg

http://www.peachparts.com/shopforum/...sc_95_e320.jpg

I have seen small flex plates used in electronic equipment to allow for
slight misalignment of control shafts. 1/4 inch shaft, etc.

Paul

On Monday, June 17, 2013 1:56:54 PM UTC-4, John Doe wrote:
This is my most recent push stick for inline skating. It works OK but

it is still being improved.



http://farm9.staticflickr.com/8524/8...3e921320_z.jpg



In the bottom right, there is a yellow gearbox.



Between that gearbox and the crankshaft inside of the orange body,

there is a 1/4 inch aluminum rod connecting the two.



Being a two cycle engine, there is some sputtering. The wheel bounces

back and forth as it turns and the gears get banged around a lot. I'm

afraid that's going to eventually break stuff.



The 1/4 inch aluminum drive rod is about 8 inches long. I would like

to replace it with something flexible, or put a clutch in there.

Anything that would absorb some shock. I suppose a clutch would have

to be at the gearbox output, since the motor spins the rod at

thousands of RPMs.



Any easy possibilities?



How about a smaller diameter 8 inch rod of spring steel? I don't know

if spring steel works that way, just asking.



Or perhaps the amount of stress when it's banging around at idle is

no greater than the more uniform stress when it's pushing me up a

hill. I could just wait and repair it as needed. I'm definitely going

to continue testing it as is.



Thanks.

On a motorcycle you'd be looking for a 'cush drive'.

http://www.pacificride.com/FileLibra...izerhubs01.jpg

Doesn't need to be anywhere near as fancy as that.

Easiest to incorporate in the wheel drive somehow.


Problem with a metal torsion spring driveshaft is if you hit a resonant frequency, things get worse instead of better.

BTW the 'sputtering' is typical 2-stroke 3-stroking, 4-stroking, 5-stroking, etc, at partial throttle settings the engine may only fire once every 3, 4, 5 etc strokes.

"Paul Drahn" wrote in message
...

I have seen small flex plates used in electronic equipment to allow
for slight misalignment of control shafts. 1/4 inch shaft, etc.

Paul

Perhaps he needs a larger flywheel to reduce torque and speed
variations.
jsw

On Mon, 17 Jun 2013 14:33:38 -0700 (PDT), wrote:

On Monday, June 17, 2013 1:56:54 PM UTC-4, John Doe wrote:
This is my most recent push stick for inline skating. It works OK but

it is still being improved.



http://farm9.staticflickr.com/8524/8...3e921320_z.jpg



In the bottom right, there is a yellow gearbox.



Between that gearbox and the crankshaft inside of the orange body,

there is a 1/4 inch aluminum rod connecting the two.



Being a two cycle engine, there is some sputtering. The wheel bounces

back and forth as it turns and the gears get banged around a lot. I'm

afraid that's going to eventually break stuff.



The 1/4 inch aluminum drive rod is about 8 inches long. I would like

to replace it with something flexible, or put a clutch in there.

Anything that would absorb some shock. I suppose a clutch would have

to be at the gearbox output, since the motor spins the rod at

thousands of RPMs.



Any easy possibilities?



How about a smaller diameter 8 inch rod of spring steel? I don't know

if spring steel works that way, just asking.



Or perhaps the amount of stress when it's banging around at idle is

no greater than the more uniform stress when it's pushing me up a

hill. I could just wait and repair it as needed. I'm definitely going

to continue testing it as is.



Thanks.

On a motorcycle you'd be looking for a 'cush drive'.

http://www.pacificride.com/FileLibra...izerhubs01.jpg

Doesn't need to be anywhere near as fancy as that.

Easiest to incorporate in the wheel drive somehow.


Problem with a metal torsion spring driveshaft is if you hit a resonant frequency, things get worse instead of better.

BTW the 'sputtering' is typical 2-stroke 3-stroking, 4-stroking, 5-stroking, etc, at partial throttle settings the engine may only fire once every 3, 4, 5 etc strokes.
How about replacing the aluminium ros with one of these (minus the
screwdriver bits, of course)?
---

Gerry :-)}
London,Canada

On Mon, 17 Jun 2013 17:29:34 -0400, Spehro Pefhany
wrote:

On Mon, 17 Jun 2013 13:55:52 -0700, Paul Drahn
wrote:

On 6/17/2013 11:43 AM, Bob La Londe wrote:
Google flexplate. Some vehicles used one made of rubberized fabric
between the steering wheel and the steering gear box. My big CNC mill
uses one between the X axis motor and the X axis drive screw made of
stacked thin pieces of stainless spring steel sheet.

Depending on your shop capabilities you could make your own.


My 1983 Mercedes 300 SD uses at least one flex plate in the drive line.
Handles lots of torque for lots of years! It's metal, I am sure.

some of the BMWs have these in the drive train- rubber and cord.
It goes between the transmission and the first drive shaft (RWD).

http://www.oembimmerparts.com/produc...FVKf4AodgwIAfA


Apparently they look like this when they're done:

http://i253.photobucket.com/albums/h...s/IMG_1156.jpg

http://www.peachparts.com/shopforum/...sc_95_e320.jpg

I have seen small flex plates used in electronic equipment to allow for
slight misalignment of control shafts. 1/4 inch shaft, etc.

Paul

Most Whirlpool washing machines use that same type of device between
the motor and the gear box. About 1.5" in diameter

http://www.ebay.com/itm/285753-for-W...-/380649737116


--
""Almost all liberal behavioral tropes track the impotent rage of small
children. Thus, for example, there is also the popular tactic of
repeating some stupid, meaningless phrase a billion times" Arms for
hostages, arms for hostages, arms for hostages, it's just about sex, just
about sex, just about sex, dumb,dumb, money in politics,money in
politics, Enron, Enron, Enron. Nothing repeated with mind-numbing
frequency in all major news outlets will not be believed by some members
of the populace. It is the permanence of evil; you can't stop it." (Ann
Coulter)

spamTHISbrp yahoo.com wrote:

BTW the 'sputtering' is typical 2-stroke 3-stroking, 4-stroking,
5-stroking, etc, at partial throttle settings the engine may
only fire once every 3, 4, 5 etc strokes.

Really? That's weird, but that's how it appears to be.

That goes for a four-stroke engine too? I never noticed that from a
four-stroke engine motorcycle.

On 6/17/2013 2:33 PM, wrote:
On Monday, June 17, 2013 1:56:54 PM UTC-4, John Doe wrote:
This is my most recent push stick for inline skating. It works OK but

it is still being improved.



http://farm9.staticflickr.com/8524/8...3e921320_z.jpg



In the bottom right, there is a yellow gearbox.



Between that gearbox and the crankshaft inside of the orange body,

there is a 1/4 inch aluminum rod connecting the two.



Being a two cycle engine, there is some sputtering. The wheel bounces

back and forth as it turns and the gears get banged around a lot. I'm

afraid that's going to eventually break stuff.



The 1/4 inch aluminum drive rod is about 8 inches long. I would like

to replace it with something flexible, or put a clutch in there.

Anything that would absorb some shock. I suppose a clutch would have

to be at the gearbox output, since the motor spins the rod at

thousands of RPMs.



Any easy possibilities?



How about a smaller diameter 8 inch rod of spring steel? I don't know

if spring steel works that way, just asking.



Or perhaps the amount of stress when it's banging around at idle is

no greater than the more uniform stress when it's pushing me up a

hill. I could just wait and repair it as needed. I'm definitely going

to continue testing it as is.



Thanks.

On a motorcycle you'd be looking for a 'cush drive'.

http://www.pacificride.com/FileLibra...izerhubs01.jpg

Doesn't need to be anywhere near as fancy as that.

Easiest to incorporate in the wheel drive somehow.


Problem with a metal torsion spring driveshaft is if you hit a resonant frequency, things get worse instead of better.

BTW the 'sputtering' is typical 2-stroke 3-stroking, 4-stroking, 5-stroking, etc, at partial throttle settings the engine may only fire once every 3, 4, 5 etc strokes.
I agree with the sputtering cause, but it should not be that way.
Something is wrong with the carburetor or it's adjustment. I have had
several 2-cycle chain saws and if they are properly adjusted, there is
no difference in running from idle to full throttle. Could the wrong
gasoline/oil mixture be causing this?

Paul

Paul Drahn pdrahn webformixair.com wrote:

spamTHISbrp yahoo.com wrote:

....

BTW the 'sputtering' is typical 2-stroke 3-stroking,
4-stroking, 5-stroking, etc, at partial throttle settings the
engine may only fire once every 3, 4, 5 etc strokes.

I agree with the sputtering cause, but it should not be that
way. Something is wrong with the carburetor or it's adjustment.
I have had several 2-cycle chain saws and if they are properly
adjusted, there is no difference in running from idle to full
throttle. Could the wrong gasoline/oil mixture be causing this?

I just bought another Echo grass trimmer. Just like the same grass
trimmer that I've had since October 2012 (the one in the picture), it
starts every time on ½ pull. But when observing closely while it is
idling, there is an obvious inconsistency in the way the sparkplug
fires.

Funny though, I'm having a difficult time finding mention of this on
the Internet. Must be a well kept secret. Maybe most people can't
hear or feel it.

On Monday, June 17, 2013 1:56:54 PM UTC-4, John Doe wrote:
This is my most recent push stick for inline skating. It works OK but

it is still being improved.



Looks like a lot of fun.
Got a video in action?

Best advice I can offer is to keep prototyping your new design ideas. With each iteration you will learn something new. You'll get there.

BTW, "sputtering" or un-fired cycles in a 2-stroke, can aid in lubrication as the fuel carries the oil, and the sputter is an extra shot of oil, so may not be all bad.

Safe skating,

--
PaulS

On 6/18/2013 11:02 AM, John Doe wrote:
Paul Drahnpdrahn webformixair.com wrote:

spamTHISbrp yahoo.com wrote:

...

BTW the 'sputtering' is typical 2-stroke 3-stroking,
4-stroking, 5-stroking, etc, at partial throttle settings the
engine may only fire once every 3, 4, 5 etc strokes.

I agree with the sputtering cause, but it should not be that
way. Something is wrong with the carburetor or it's adjustment.
I have had several 2-cycle chain saws and if they are properly
adjusted, there is no difference in running from idle to full
throttle. Could the wrong gasoline/oil mixture be causing this?

I just bought another Echo grass trimmer. Just like the same grass
trimmer that I've had since October 2012 (the one in the picture), it
starts every time on ½ pull. But when observing closely while it is
idling, there is an obvious inconsistency in the way the sparkplug
fires.

Funny though, I'm having a difficult time finding mention of this on
the Internet. Must be a well kept secret. Maybe most people can't
hear or feel it.
I assume you do not have a way to watch the output of the magneto to see
if it is the problem. Pull the spark plug and check/set the gap to the
recommended value.

If you have access to an oscilloscope, wind a few turns of insulated
wire around the spark plug wire and attach the scope probe to the wire.
should be able to see a pretty good trace of each plug firing.

Paul

On Tuesday, June 18, 2013 11:45:03 AM UTC-4, John Doe wrote:
spamTHISbrp yahoo.com wrote:



BTW the 'sputtering' is typical 2-stroke 3-stroking, 4-stroking,

5-stroking, etc, at partial throttle settings the engine may

only fire once every 3, 4, 5 etc strokes.



Really? That's weird, but that's how it appears to be.



That goes for a four-stroke engine too? I never noticed that from a

four-stroke engine motorcycle.

No, only happens on 2-strokes, it happens because at some load/speed/throttle triple-points the cylinder fires, traps a lot of exhaust that keeps the next cycle from firing, maybe the cycle after that it's too rich... all kinds of really cool almost organic behaviors.

On Mon, 17 Jun 2013 19:22:11 -0400, wrote:

On Mon, 17 Jun 2013 14:33:38 -0700 (PDT), wrote:

On Monday, June 17, 2013 1:56:54 PM UTC-4, John Doe wrote:
This is my most recent push stick for inline skating. It works OK but

it is still being improved.



http://farm9.staticflickr.com/8524/8...3e921320_z.jpg



In the bottom right, there is a yellow gearbox.



Between that gearbox and the crankshaft inside of the orange body,

there is a 1/4 inch aluminum rod connecting the two.



Being a two cycle engine, there is some sputtering. The wheel bounces

back and forth as it turns and the gears get banged around a lot. I'm

afraid that's going to eventually break stuff.



The 1/4 inch aluminum drive rod is about 8 inches long. I would like

to replace it with something flexible, or put a clutch in there.

Anything that would absorb some shock. I suppose a clutch would have

to be at the gearbox output, since the motor spins the rod at

thousands of RPMs.



Any easy possibilities?



How about a smaller diameter 8 inch rod of spring steel? I don't know

if spring steel works that way, just asking.



Or perhaps the amount of stress when it's banging around at idle is

no greater than the more uniform stress when it's pushing me up a

hill. I could just wait and repair it as needed. I'm definitely going

to continue testing it as is.



Thanks.

On a motorcycle you'd be looking for a 'cush drive'.

http://www.pacificride.com/FileLibra...izerhubs01.jpg

Doesn't need to be anywhere near as fancy as that.

Easiest to incorporate in the wheel drive somehow.


Problem with a metal torsion spring driveshaft is if you hit a resonant frequency, things get worse instead of better.

BTW the 'sputtering' is typical 2-stroke 3-stroking, 4-stroking, 5-stroking, etc, at partial throttle settings the engine may only fire once every 3, 4, 5 etc strokes.
How about replacing the aluminium ros with one of these (minus the
screwdriver bits, of course)?
---

Gerry :-)}
London,Canada
missed the link -
http://www.harborfreight.com/7-piece...ent-68514.html
---

Gerry :-)}
London,Canada

There is no problem. Just like the duplicate grass trimmer (Echo GT-
225) I've had since October 2012, it starts on ½ pull, it has lots of
power, and it runs smoothly when it's revved. It almost starts when I
look at the cord It's like they designed the thing around easy
starting. But I suspect it just points to overall quality.

I'm pretty sure they can be tuned to run properly at certain speeds.
So if it runs perfectly at idle, it might sputter at some other
speed. I'll post more if I find other discussion on the Internet.

http://www.thumpertalk.com/topic/372...ottle-sputter/

There's one thread. No doubt there are many more. Anyways, it's just
amusing to me.

Yesterday, another failure occurred. This time, it wasn't one of my
sloppy connections, the right angle gear taken from a Dewalt 18 volt
cordless drill broke. Feels like sort of a triumph

The great thing about gas is that it goes a very long way compared to
battery power. Unfortunately, the motor is heavy. This 21.2 CC engine
has just enough power.

Inline skating will be ready for this when battery technology is much
improved. For now, I might use my new engine to make a gas powered
scooter, instead. And this time, I won't remove the gas trimmer's
built-in clutch.

Maybe another electric version is in order, for short & fun trips.
When I can do it.

http://www.youtube.com/user/pqxxedf/videos





--
Thanks to the replies.

Actually, the right angle gear breaking is not a surprise, since
there was no support on the other side of the wheel opposite of the
right angle gear.