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Member postings for Roger Holebrook

Here is a list of all the postings Roger Holebrook has made in our forums. Click on a thread name to jump to the thread.

Thread: Class 37 Locomotive Suspension Springs
09/07/2018 19:19:20

I am trying to establish the specification for the (16No. in total) suspension springs as fitted to the Dan Jeavons design, circa 1995, for the cast aluminium power bogies on the Class 37/50/55 battery/electric locos. It is the physical size/number of turns/material and spring rating I require, so that I can form a base line for different loading and track conditions.

Thread: Lee springs
18/01/2016 16:28:55

I too have recently ordered from Lee Springs and found their service excellent!

Thread: V twin double acting oscillating engine.
20/07/2015 12:26:00

Can I suggest the article "starting in steam" by Peter Arnot , in Model boats magazine commencing in June 1988. Just as a matter of interest, there is also a four cylinder version with both boiler and boat design.

I am building both the two and four cylinder versions myself.

Roger

Thread: 08 Locomotive suspension
04/06/2015 18:06:51

The bare frame has been assembled for a trial fit together with the six suspension springs. The springs are as specified on the plan and supplied by one of the ME suppliers. These springs are 1" long by 5/16" 18swg and 8 turns. They also appear to be "music wire" as opposed to stainless steel.

However, when only partially loaded(two small lead acid batteries) the springs are fully compressed. Now there have been many 08's built to this design, so has anyone else experienced this problem and how was it overcome?

Thread: Canterbury Lamb/Invicta 3 1/2" Boiler
08/12/2014 14:31:03

From the drawings I have the dimension(excluding smoke box) is 8 9/16" ( eight and nine sixteenths inches) The fire box is 2 7/16" and the remainder of the boiler 6 1/8".

Hope this is useful, if you need anything more come back to me.

Regards Roger

Thread: Electric motors
24/09/2014 10:49:58

Michael - Thank you for your help, I have to confess I'm a little out of my depth here so I'll have to look into this and try to get some expert guidance.

Many thanks Roger

21/09/2014 12:34:08

Thank you all for your speedy response to my problem.

Bob - The motors you show the link to appear to be the 3000 rpm sold by LEMAC (Leith Electrical) and would with the right gear ratio seem to be the way forward.

Neil - I will look at the golf-cart motors and see if I can fit them as axle mounted between the wheels. There is a firm called Petrol-Scooter that sells a good range.

Ian - The Charlatan was originally designed to run on Lucas 78550 windscreen wiper motors. I have used a tachometer to check their speed and they give a no-load speed of 3500 rpm.

I have considered running 12 v motors at 24 volts but the thought makes me nervous.!

Many thanks for your input, you have given me lots to think about.

Roger

20/09/2014 12:52:54

I have under construction an 08 shunter to the 1980's design. The main drawing shows 4No. car wiper motors plus gearing and a subsidiary drawing shows 4 No. conventional mounted axle motors and several alternative gear ratios.

I am trying to achieve approx. 500 watts and be capable of an average speed of 10 mph. My problem is finding motors of approx. 120 watts of either 12 or 24 volts, and with a no-load speed in excess of 6500 rpm and capable of fitting between the wheels. I have looked at the websites of most major manufacturers, e.g. Buhler/Johnson/Mabuchi etc., (some sites are really hard going) but not found anything that fits the criteria.

There are many motors (of Chinese origin) on the market but they have an average of 2400 rpm no-load speed.

I would like to avoid the use of wiper motors as in many cases the specification is unknown and I'm told the central mounting can flex causing the pinion to become disengaged.

If my maths are correct and based on a wheel diameter of 4.75 inches over the tread and an arbitrary motor speed of 2000 rpm, for the purpose of calculation, I have tabulated below the track speeds of the given gear ratios on the drawings.

Gear ration/speed for Charlatan Loco:

(2000rpm is an arbitrary speed for calculation)

Motor Wheel diam Pinion Driven Speed(mph)

2000 4.75 in 14 108 3.65 mph

Gear ratios shown on supplementary plan for M.O.D.

(and alternative motor mounting)

2000 4.75 in 15 80 5.28 mph

2000 4.75 in 12 85 3.98 mph

2000 4.75 in 10 90 3.13 mph

As you can see, the track speed on average is only slightly more than 3 mph, hence the need for a higher speed motor.

The only motor I can find that comes anywhere near the specification I think I am going to need and is currently available is the one sold by MFA/Component shop but even that one is only 80 watts and I can see no physical room to squeeze in a fifth motor. I will try to give below the link to that motor.

**LINK**

So, if anyone knows of suitable motors and suppliers or even an alternative I would be grateful to hear from you.

Roger

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