Proper Gear Alignment for LMP Chassis

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Ned
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Location: Sedona, AZ USA

Proper Gear Alignment for LMP Chassis

Post by Ned » Sat 10. Dec 2016 14:17

In order to get the motor and gears to fit under an LMP body, I have used an inline motor configuration, whereby the shaft of the motor runs perpendicular to the rear axle. I assume that the centerline of the motor shaft should intersect the centerline of the axle. Is that correct?

When chassis are built using my chassis kits CK3 or CK4, the centerline of the motor shaft runs under the centerline of the axle by .006” (.152mm). That’s about the thickness of 2 pieces of computer paper. The misalignment does not seem to have any practical significance.

Currently, the designs require that the motor be glued to the frame after the wheelbase is established. Once glued to the frame the wheelbase cannot be changed. If I modified the design so that the motor was glued to the floor of the motor pod instead of the frame, then the wheelbase could be adjusted after the motor is glued in place. This is clearly preferable.

If the motor was glued to the motor pod, the centerline of the motor shaft would run .024” (.610mm) above the centerline of the axle. That’s about 4 times as much misalignment. However, the axle diameter is .094” (2.38mm), so the misalignment would be about ¼ of the axle diameter.

Do you think that much misalignment would be a problem? Would the car run? Would the gears wear out much faster?

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Keld
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Re: Proper Gear Alignment for LMP Chassis

Post by Keld » Sun 11. Dec 2016 09:03

If the gear is not in correct place, yes it will be a problem, but for most people they would never find out.

There will be a bigger tracktion in the contact between the pinion and crown gear, and the car will go slower, use more power, and of course the gear will wear out faster.

But what about using double layer tape under the motor? would that be the solution to raise the axle height?
/Keld

Nor Cal Mike
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Re: Proper Gear Alignment for LMP Chassis

Post by Nor Cal Mike » Thu 15. Dec 2016 23:37

Since you are using slot car gears, & axles anyway, Slot.it makes an offset crown gear that will allow you to mount your motor a little lower than centerline of the axle.
Mike

Ned
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Location: Sedona, AZ USA

Re: Proper Gear Alignment for LMP Chassis

Post by Ned » Fri 16. Dec 2016 13:41

Nor Cal Mike wrote:Since you are using slot car gears, & axles anyway, Slot.it makes an offset crown gear that will allow you to mount your motor a little lower than centerline of the axle.
Mike
Thanks Mike. I didn't know that this type of gear existed.

Nor Cal Mike
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Joined: Fri 21. Dec 2012 22:22

Re: Proper Gear Alignment for LMP Chassis

Post by Nor Cal Mike » Sat 17. Dec 2016 11:47

I am not recommending this shop over any other. They were simply the first one on the list I got when I did a search for Slot.it Offset Crown Gear. I am posting this as an illustration of the type of gear I am talking about. https://www.lebhobbies.com/sigo29b-slot ... oCNefw_wcB

Mike

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