5" Driving Car Question

[ron]

Hi All
A little advice please about driving cars from those in the know.
Any driving cars I've seen tend to have a bogie at each end with 4 small wheels, however I have four spare Simplex wheel casings [4 3/8" dia. over the tread] and wonder if I could make a simple [and cheap!] 4 wheel driving car by the following method.
I have a pile of 2" x 1/4" galvi angle iron from which I could weld up a 3 or 4 ft long rigid frame, use four 3/4" bore plummer blocks bolted to the underside of this for bearings and fit a brake possibly made or modified from a mountain bike disc brake system to one of the axles.
It would obviously need some sort of padded superstructure for a seat as well, does anyone see any fundamental flaws with this idea or have any suggestions they can add?
Ron

[John Lee]

The problem is making it go around corners Ron, which is why you do not see this much.

If the wheelbase is short enough to go around reasonable curves, then it will be a bit "tippy", but will be ok if you are careful mounting and dismounting.

Hence a couple of bogies for anything 3 foot or so long, or more.

Regards,

John

[baggo]

Hi Ron,

the majority of driving cars I've seen are 4 wheelers but they tend to be only about 18 to 24 inches long, just long enough to park your posterior and perhaps a coal bunker at the front. Thus the wheelbase is still fairly short and they will go around most curves quite happily. Extending the length to 3 or 4 feet may cause problems running around tight curves due to increased friction , hence the use of two four wheeled bogies on the longer cars (as John has already said above) . However, there's no harm in trying it.
Most trolleys seem to use a disc brake system based on mountain bike brakes so no problem there.

John

[Boadicea]

Ron, agree with Mr. Baggo.

The following works for me....
12" between axles (wheelbase)
Body 20"x 8".
Depth 2½" (metal) plus cushioning mounted on top of a light wooden frame.

Needs some sort of suspension to help the rump - just simple springing - possibly roller or phosphor bronze bearings in horn blocks with a spring each side - a bit like your loco only not as elaborate. Rubber suspension blocks may also be available.

Enjoy a good ride!

Regards, Bo.

[ron]

So basically the idea is OK as long as I keep it short.
The plummer blocks look a very simple way of making axle bearings and they are available cheaply on Ebay, I'll maybe fit a thick piece of insertion rubber between them and the chassis to act as a primitive suspension to keep my rump in prime condition ;D
Mind you, you girls should have an, ahem, advantage in this department

Ron

[chris vine]

Hi Ron,

The plummer blocks should be fine and you can use springs on longish bolts/posts above them to make really good suspension.

One thing: Make sure that whatever springing you use that the bearing can drop down a bit further so that one wheel can follow down into a dip if the other three (or even just one) wheels has not compressed its springs. This way you will have very few derailments.

Rubbish weather up here eh?!!

Chris.

[ron]

Hi Chris
Thanks for the info, weather getting beyond a joke, that was some storm on hogmany, spent the 2nd re-felting the garage roof, and I'm still clearing up the wreckage of a pergola that was blown over, a lot of damage to property around here, I got off quite light, I have several large trees in the garden and it was seriously loud and scary during it!
Ron

[chris vine]

Ha Ha Ron!!

I spent the 3rd putting felt back on my workshop roof and it still leaks in one place....

What the others have said about lenght of wheel base is true. My curves are 30 foot radius in 7.25 gauge. This is really too tight, 45 would be better and 60' would be fine. It is very noticeable on my wagons that there is a lot of friction on the curves, this is because the wheelbase is rather long. If you watch closely, you can see the flanges travel across the rail head when they get to a curve and then grind along, causing a lot of drag.

Chris.

[spurley]

Hey Chris

I thought the drag was really my bulk on your wagons, nothing to do with curve radius ;D How wrong I can be

Happy New Year

Brian

[JohnP]

You can have a 4 wheel driving truck with a long wheelbase if the wheelsets are allowed to self steer. There was a series of articles in ME describing an arrangement by David Hudson which does this. The suspension system is a swinging link arrangement with the actual suspension and a degree of the aligning forces provided by what are actually toilet seat rubbers! I believe the rights were passed on to Dave Noble, and although I've seen a prototype on his stand at one of the exhibitions, there's nothing on his website.

Regards,

JohnP

[greasemonkey]

HI JohnP
Dave Nobel supplies drawings and all parts to build one if you want. I've got one that I built from the articles David wrote for Model Engineer and they give a very good ride. Havent noticed any tendancy to tip regardles of were I sit and two disks fro braking using cylce brake blocks. Here are some piccies of it durign construction.

s142.photobucket.com/albums/r100/AndyA01/Driving%20Trolley/


Andy

[Shawki Shlemon]

Hi ron
As long as you remember the curve( radius) on the track should not be less than 20 times the wheel base you will be OK .

[JohnP]

Andy,

I've got one of those driving trucks too! I bought the drawings from David before he published them, but the driving truck still isn't finished! - And I did the simple version without vacuum brakes...

It does give a very smooth ride though.

Cheers,

JohnP

[steamjohn248]

I've got the Dave Noble Drawings too, brilliant design but they are still in the drawer, Takes me all my time to build locos (and anyway I thought Ron mentions the word "Cheap" in his orriginal post). Beautiful bits of Kit, saw one at the M.E.Exhibition but cheap they ain't.

Why not build a short wheelbase four wheeler but pivot the front axle with a draw bar to the loco rear hitch. that should steer round the corners ok. I'm old enough to remember 'Soap box carts': four old pram wheels and axles, a plank, a box and a bit of rope to steer with, but perhaps Ron is'nt.

Cheers

John

[Tony K]

I'm old enough to remember 'Soap box carts': four old pram wheels and axles, a plank, a box and a bit of rope to steer with, but perhaps Ron is'nt.

John, that must have been before the computers arrived then! ;D

Regards, Tony

[greasemonkey]

Hi Steam John
They dont have to be expensive! I didnt use any 'comercially' made parts I turned/profiled all from bar stock and I reckon that it didnt cost me more than £60. The time taken though was expensive. I spent 4 months making the first and setting the lathe up, but once set it was easy to produce the parts which is why I have enough to make a second one when I have some spare time!!
I can remember soap box derbys, great fun and sadly something the kids of today are going to miss with all the cotton wool and padding.. opps sorrry health and saftey!! And Im not yet 40!

Andy

[ron]

Hi Steamjohn
Unfortunately [or fortunately?] I'm old enough to soap box carts, we called them 'traces' which seems to be a local Ayrshire name for them. I've still got the scars on my knees [and other places] from adhering to the design principle that 'brakes are for cissies' ;D
Andy
That design looks like a very posh driving car, I was really looking for something cheap and simple and I think I've enough info now to make one successfully, all I need to do is complete the loco first thanks to everyone who responded.

Ron

[dscott]

Just a quick addition with my bogie driving car I have one wheel running free in a large bearing, sort of differentual and on a 40 foot curve the outer wheel moves a whole 1/4" forward then back when it returns to the straight. Yes and they are bogies.
No squeels.
David.