A New Home for my Benz Engine

[Sprocket]

I wondered what you were going to do for tires...
Doug

 

[ddmckee54]

Have you ever watched Dave on the Engel's Coach Shop when he's repairing a buggy wheel with solid rubber tires, it's QUITE the procedure. Yours' is much simpler, nice work.

Don

 

[Rdean33422]

I wondered what you were going to do for tires...
Doug

I didn't know how it would work but just gave it a try.

Thank you Don but I don't think mine would last very long on a buggy.

I had mentioned earlier that the engine looked like it was too far forward and would cause some problems later on. Then the real problem struck me, the engine is too big. I had used many different sources to size the wagon frame foot print and came up with a size that would work for me. I was quite happy that my frame was very close to the scale the others had used but I forgot one thing my engine was not at the same scale as the frame. When I built my engine I used materials I had on hand. Sizes that worked and looked good together not to any scale.

I am going to continue on with the same engine and frame but with some modifications and still try to end up with a recognizable model of the original. First was to move the engine back 2" by installing two steel plates to the frame. Move the rear wheels higher on the frame but that would at the cost of the rear leaf springs.

See the plates I added for the engine here.


Side view.


With the engine.


Side view


The frame is lower to the ground and the engine is back out of the way.
The front wheel now is at the right height in relation to the frame.

Looks much better to me what do you think?


Thanks for looking
Ray

 

[TonyM]

Do you have this drawing Ray? I missed sending it with the others. It looks like you could push the engine much further back as the crank is just in front of the rear of the back wheels on the original.

 

[Rdean33422]

That is one I haven't seen Tony. There are many things on that pdf that are different than the actual one Benz built. The most striking feature that is different is the frame and steering. With the engine that far back from the center line of the rear wheels the auto would have been prone to tipping over backwards.
Benz made many changes to the original patent drawings over the 2 years or so before it was driven on his wife's famous journey,

Ray

 

[Rdean33422]

We are at 28" overall length and for that size the wheels needed to be larger to keep to scale. I don't think it looks too bad so I will continue.
I worked on the front wheel and mount.






I have some work to do on the mower and then we will be gone the rest of the week.
I need to come up with a gear reduction unit to lower the speed.

Thanks for looking
Ray

 

[TonyM]

That engine location looks OK. The diff pulley could be arranged to reduce the speed a bit. Also the sprocket ratio could help.

 

[Rdean33422]

Thanks Tony
Ray

 

[Rdean33422]

I was able to get some shop time today and tried my hand at making sprockets.


These are 10 tooth and 30 tooth sprockets 0.188 thick for #35 chain on the final drive.
Polished and installed.


More gearing to design for the internal parts.

Thanks for looking
Ray

 

[Rdean33422]

I have all the gears for the reducer cut and they turned out great.


Now to work on the housing to hold them.

Thanks for looking
Ray

 

[ajoeiam]

I was able to get some shop time today and tried my hand at making sprockets.
View attachment 149389

These are 10 tooth and 30 tooth sprockets 0.188 thick for #35 chain on the final drive.
Polished and installed.
View attachment 149390
View attachment 149391
More gearing to design for the internal parts.

Thanks for looking
Ray

Interesting - - - - what kind of cutter did you use to do the sprockets?

TIA

 

[Rdean33422]

I cut them with a 0.125 end mill on my CNC machine.
Thanks for asking

Ray

 

[ajoeiam]

I cut them with a 0.125 end mill on my CNC machine.
Thanks for asking

Ray

Thanks - - - - did you program the toolpath yourself?

(I might have need of such but for larger than #35 chain.)

 

[Rdean33422]

ajoeiam
I did not manually program the tool path.
McMaster Carr is a great source of DXF files for all the gears and sprockets they sell for free download. Find the sprocket you want, down load the file and import it into your cad/cam program. Generate your tool path and go to the machine.



After much ado I did get the housing completed. It is a double reduction gear setup centering around the fixed center gear that makes for spacing the other two shafts critical. I did fudge a little on the first shaft to get a nice tooth depth but the last shaft was right on spot. Don't know how that happened but I will take it.


Now I will try to get this mounted in the frame next to the engine. I can already see some interference problems that will have to be worked out.

Thanks for looking
Ray

 

[Rdean33422]

I did get the gear box mounted with one bolt today.


I need to get the chains on before I can determine just where the second bracket and bolt will be. I was going to make a differential drive but I think it will work fine with a straight axle.

Thanks for looking
Ray

 

[ddmckee54]

Since all you probably want to do with this model is putt around a little bit, a straight axle will probably work just fine. Besides, there's an AWFUL lot of RC cars and trucks out there that are running with a straight axle instead of a differential. You can always build a differential as an "upgrade", that's what WPL does.

 

[Rdean33422]

I totally agree with you and I do have the differential gears on order so maybe some day.

I made a couple of bushings for the small chain sprockets and temp installed the chains to determine where the other gear box bolt will go. I may have to make an off set bracket for the gear box mount but will see.

The right side of the main shaft is close enough to the gear box that it won't need another bearing at the frame rail.


The left side is going to have a brass bushing and a bracket attached to the frame rail for the main shaft.

Thanks for looking
Ray

 

[Rdean33422]

It really is better to be lucky than good as the second bolt for the gear box goes directly through the frame rail. Bolted there both chains are at a nice tension and no 1/2 links were used.


I made and installed the left side main shaft bearing and you can still easily turn the shaft with your fingers. The shaft goes through 3 bronze bushings and the last gear reduction gear so there are many places for binding but I got lucky again.


Thanks for looking
Ray

 

[stevehuckss396]

This is going to be one great model. Nice job so far.

 

[Rdean33422]

Thank you Steve I hope it will be an acceptable version.

I added a 1" wide plate for the gas tank and throttle lever to mount to.


Mounted the hall sensor on the right side.


This is just a mock up of the drive belt to check the alignment of the pulleys.


Thanks for looking
Ray