Brunel Vertical Boiler Engine

A very popular starting point for Live Steam. With their low cost comes a number of problems which can be discussed here
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Chris Cairns
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Post by Chris Cairns » Fri Aug 09, 2013 5:45 pm

I only posted that video URL as an extreme example of the condensate problem these piston valve cylinders suffer from. If the owner had been watching his pressure gauge more closely he/she would have seen the large pressure drop (about 20PSI) as soon as the regulator was opened. Waiting for the pressure to rise again would have shortened the process of clearing out the condensate.

When I was reviewing the Brunel I discussed the lack of a condenser tank with Mamod. Garden Rail had previously reviewed the first Brunel produced and had recommended that customisation of the locomotive should be left up to individual owners requirements. So no condenser tank was fitted, unlike most other De Winton type locomotives available. I also questioned why the piston valve block had 2 exhaust holes (the original block fitted to the Golden Jubilee & William locomotives only had one exhaust hole) and was told it was for improved lubrication - I suspect it was an attempt to overcome the jerking/locking up that the condensate initially causes. I've blocked the 2nd exhaust hole on both my Brunel & William II locomotives.

Matt - the burner suffers from 2 problems which causes the flaring up. Firstly you need to wait a short time after initially lighting the burner for it to warm up before turning up the gas (it is in the instructions that we all have read previously!). The other problem is they are generally mounted at one end of the burner mounting slot which places the edge of the burner too close to the chassis cut-out which then affects the burn pattern. Moving the burner in the slot towards the centre of the boiler prevents the burn pattern straying sideways. I was surprised to find mine had a partially blocked jet which after clearing out has greatly improved the burner.

It seems that Mamod have finally acknowledged the deficiency of their total displacement lubricators and have fitted a re-designed in-line lubricator on the SP6 stationary engine - http://img708.imageshack.us/img708/5416/se4h.jpg

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Post by mikewakefielduk@btinterne » Fri Aug 09, 2013 6:04 pm

At last, a proper displacement lubricator! In fact, not only will it work much better than the original box design but probably be far cheaper to make. After all, its mainly just a tube with a treads at either end.

Now how can you fit one of those to an existing Brunel? Should be possible but you'd probably have to leave the existing one either in situ or fashion some other way of supporting the cylinder.

As for the lack of a condenser tank, I know that Mamod have fitted at least one to a Brunel at the customer's request. They use a lubricator from a Mk11 as the tank.

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Post by Bill/Rubery » Thu Aug 29, 2013 7:28 am

I have a horrible feeling that the Brunel is a 'work in progress' as far as buying one! My Brunel has gas flaring at the burner and I can only turn up the gas say half a turn of the gas control nob. Any higher and the gas is licking at the cog wheels! I asked Mamod about this and they suggested the flaring was... "due to a blocked gas jet"...the gas jet is clear! I am beginning to wish I had purchased a Roundhouse 'Bertie' as one gets a up and running loco....not a 'work in progress'!
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Post by Chris Cairns » Thu Aug 29, 2013 2:03 pm

Bill, see my comments above regarding burner flaring.

Firstly you need to light up the burner on a minimum setting then wait about 30 secs for the ceramic to heat up and then you can turn the gas up. Like your Brunel I have marked my gas control valve and using Butane indoors I do not open the valve as much as half of a turn (usually about a quarter of a turn when running).

The other problem that can affect the burn pattern is Mamod tend to mount the burner at the far end of the mounting slot thus putting the burner too close to the chassis cut-out (and the photo of Jakarna on your website would seem to confirm your burner is mounted in the same position). By moving the burner closer to the centre of the cut-out you reduce the chance of the burn pattern creeping out under the cut-out.

And I would not dismiss a blocked jet. I have been running my Brunel for some time but only recently found that the gas jet was partially blocked which after cleaning out increased the burner performance.

Mamod are a much smaller manufacturer than Roundhouse in terms of number of locomotives produced (Brunel's were/are made in small batches), and they do not have the 8 hours running with a load around the factory track that Roundhouse apparently employ (hence the difference in cost). Roundhouse also do not use a ceramic burner.

Whilst Mamod seem to have got it right with their oscillating cylinder locomotives (the former Mamod Train/Mark I, the current Mark II & Diamond Jubilee locos) which run great straight out of the box, the same cannot be said of the piston valve locomotives. It will be interesting to see if the revised piston or slide valve cylinder actually gets produced for the Thomas Telford locomotive as their current development is focused elsewhere.

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Post by mikewakefielduk@btinterne » Thu Aug 29, 2013 6:51 pm

I couldn't agree more Chris, you need to be very gentle with the gas valve when you first light the burner.

Its not unique to Mamod, I need to do exactly the same with all of my Regners.

You also tend to pay for what you get, a Roundhouse Bertie loco is getting on for twice the price of a Brunel.

Personally I think Mamod's are great simply because they are that much cheaper and the build quality and detailing is sometimes missing. It means I don't have so many qualms drilling out rivets and changing things because if it goes wrong I'm not that much out of pocket. For example, my Brunel has been radio controlled, then re-geared and then the radio control taken out again. Its left a few holes but, to me, that's what Garden Railways is all about. I most certainly would have thought twice about doing the same to a loco that cost a lot more.

I would also add that I've found the staff at Mamod particularly helpful and obliging.

Mike

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Post by Chris Cairns » Thu Sep 12, 2013 2:49 pm

The Mamod vertical boiler & marine oscillating engine is now under development with Deans Marine - http://youtu.be/G0xc3LUHDLI

Somewhat brave posting an unedited video. The throttle linkage should have been fixed before steaming surely. And it appears that the engine is not quite self starting although I'm sure that would improve with running in. A leaky safety valve seal and the pressure gauge banjo bolt fitting leaking as well - not a good advert for Mamod's quality control.

Nice to see safety is their No.1 priority by fitting a nylon gas pipe again - look forward to the next video of the 1st steam launch going up in flames!?!

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Post by Lner fan Sam » Thu Sep 12, 2013 3:52 pm

I have seen that vid to and noted that the pressure dropped badly on the pressure gauge with that engine... :|
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Post by Chris Cairns » Thu Sep 12, 2013 4:23 pm

Initially he was running it with the reverser valve fully open (no adjustment of the boiler mounted throttle so I guess it was fully open) but he made no adjustment to the gas valve (and the burner is not mounted yet so was free to move). However in the later part of the video he uses a more realistic setting of the reverser valve which seemed to hold the pressure better, and as he said during the video it needs a better propeller to steam engine combination.

I'm sure you would equally have difficulty maintaining pressure on your MSS with the throttle & reverser valves fully open!

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Post by Chris Cairns » Wed Oct 09, 2013 1:50 pm

Having ditched Twitter, Mamod are having a go with Facebook but it is currently more of a history lesson. Here is their Brunel entry: -
The Brunel Locomotive - 2010: This model is a 'Dewinter' type engine, completely different from the previous Mamod locomotives. Also this engine was the first model to be geared and have a vertical boiler. It was first issued with fixed wheels at either '0' or '1' gauge; it has since been modified to be dual gauged by adjusting centres with an allen key.
What is a Dewinter type engine?!?

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Post by Bill/Rubery » Mon May 12, 2014 12:40 pm

I emailed Mamod about the Mark two engine recently. I don't know anything yet about being able to add the current improvements to my Mark One Brunel. (like the new gearing) I feel quite 'miffed' that I paid out good money only to find that my Brunel is out of date due to 'improvements done only one year later! When I purchased my old Millie in 2004 it was FULLY ready for sale and no doubt the 2014 'Millie' has the same specification as my old one! Yes I feel quite cheesed off....
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