SlotForum banner

1 - 8 of 8 Posts

·
Registered
Joined
·
3,646 Posts
Discussion Starter · #1 ·
hi! if i position the pinion gear [ angle-sidewider] below the axle centreline will it tend to pull the front end down on accel
eration, or just unway the back wheels causin sliding or hopping. anyone tried it. john.
 

·
Registered
Joined
·
251 Posts
This is in effect what Slot.It do with their offset engine mounts. The end result should be that you lower the centre of gravity because the motor will now be lower in relation to the ride height. This has to have a positive effect on the handling.
You don't say what car you are modifying is it a brass chassis scratch build or a 1/32 Hard bodied car with a plastic chassis?

Cheers
Steve
 

·
Premium Member
Joined
·
2,143 Posts
Don't think running below or inline with the axle will make any differance apart from better handling because of the lower c.o.g but bad meshing and possible premature failure when running too far below, the old Taylormade wide anglewinder gears come to mind!
To keep the front end down depends on how much tourque your motor produces and in which direction it rotates in relation to the driven axle, less noticable in plastic cars than the much more powerfull BSCRA type cars.
[oneofwos]
 

·
Registered
Joined
·
3,646 Posts
Discussion Starter · #4 ·
hi, chassis is scratcth built wire/brass, so motor can go where i put it.the reason i ask is because of the lever effect, if i wanted to build a wheelstander the pinion would be high relying on the axle trying to pivot aound the drive pinion and lift the front wheels, i just wondered if the reverse happens to a lower centreline pinion on a circuit car, 67 pontiac 1/32 hardbody. lets have your theories and results if youve played about with this setup............john
 

·
Registered
Joined
·
3,570 Posts
Hi Stoner
That leverage effect you describe exists.
There is also a couple resulting from motor torque trying to lift the nose on acceleration which is independent of the where the motor sits relative to the axle centre line.
There is also a couple resulting from height of the c of g above where the tyres traction acts, this is also independent of motor position and is trying to lift the nose on acceleration (assuming the c of g is above the track surface, which it always is in a practical slot car).

The important question is how large are each of these effects. It is straightforward to calculate the relative sizes of the first two effects by taking moments about the motor and axle centreline. The third can also be calculated, this also depends on the height of the c of g.

In the extreme case where the motor shaft is vertically below the axle, this effect you describe would be significant. With practical slot car gears and wheel sizes you don't approach that, so the leverage effect you describe is small compared with the other couples trying to lift the nose on acceleration.

Practical experience is that for most slot cars a lower c of g gives advantages in cornering and handling, this seems a more important reason for getting the motor as low as possible than the above effects.
(That's another story, so I won't go into all that here.)
 

·
Registered
Joined
·
3,646 Posts
Discussion Starter · #6 ·
thanks guys, more bennefit from lower cog than any theoretical leverage with a hot motor. john.
 

·
Registered
Joined
·
3,646 Posts
Discussion Starter · #7 ·
hi, ijust built the wire brass chassis for 1inch natural rubber tyres. its got a hawk neo 6 sidewinde 5.6 to1 gearing and the motors way below axle line 1mm ground clearance, im just tuning the chassis at the moment its got a 10 gram tyre weight in the front and its showing promise. its a aa/f fuel altered fiat ,its actually a drag racer but it really looks good on my normal road race circuit. john.
 

·
Registered
Joined
·
3,646 Posts
heads gone just put up double post, due to smallest grandson, not my age honest. the reason i put post in this section because its an all wire chassis miny version of a wing car, single wire centre and wire perimeter frame, with droparm, which will go for the road race version. its so light i can put weight any where and play with torsion rod thickness. john
 
1 - 8 of 8 Posts
Top