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[pettyofficernick]

After a brief dalliance with water jets and brush-less motors, I have now started building the African Queen. I got the hull from Kingston Moldings last year, and have been concentrating on preparing the engine and boiler for installation in the hull.
http://www.kingstonmouldings.co.uk/pdafricanqueen.htm
http://www.modelboatmayhem.co.uk/forum/index.php/topic,39299.0.html
The hull really is a superb molding, clean, crisp and trimmed to profile, no work needed at all except for a quick wash to get rid of release agent and a swipe with a bit of sandpaper to get rid of the molding line.
First job was to drill the hole for the prop-shaft, followed by fitting beech engine bearers, and mahogany and beech beams to support the floor. The engine is coupled to the shaft with a coupling made from a  Meccano wheel  and a pair of 1/8" roll pins in the flywheel. Now the position of the machinery is established, the engine and boiler can be removed for lagging and painting.
The firs 2 photos are the engine, boiler and ancilliaries mounted on a tray for removal as a unit for servicing....



Next up is the framework and engine bearers....


And finally, the steam plant in position...
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[Capt Podge]

I know nowt about steam engines but that one looks beautiful - a work of engineering art - well done that man 
 
 
Regards,
 
Ray.
 
 

[pettyofficernick]

I know nowt about steam engines but that one looks beautiful - a work of engineering art - well done that man 
 
 
Regards,
 
Ray.

You are too kind sir, the engine was a machined kit, the boiler was bought from Maccsteam, all I did was to bolt it all to a steel tray and make a few pipes.....

[Norseman]

" Yeah. The shaft's twisted like a corkscrew and there's a blade gone off the prop."

Don't forget that bit Nick

Dave

[pettyofficernick]

" Yeah. The shaft's twisted like a corkscrew and there's a blade gone off the prop."

Don't forget that bit Nick

Dave

To what are you alluring, old thumb?

[dreadnought72]

 

Andy

[pettyofficernick]

I will, at some point, be needing a 1/10th scale Humphrey Bogart and Kathrine Hepburn. Is there a company that makes figures from the movies I wonder..... Dave, it is a while since I watched the film, I think a viewing is required to refresh my memory. The part that sticks in my mind is when  she chucks his gin overboard,  ' Oh no miss, you didn't oughta have done that.......' When the movie was shooting in the Congo, Katherine Hepburn was constantly complaining about John Houston ( director) and Humphrey Bogart's drinking habits, ie, whiskey, constantly. Everyone in the crew got dysentery, except for JH and HB, now that says something!

[Jerry C]

Oooh goody, at last. I've been waiting for this bit for about 4 months. I think should I ever build another I will go the GRP route. Looking good matey. What's your ETC, any chance you'll be ready for Coniston on 29th May? All the best,
Jerry.

[pettyofficernick]

Good Morning Jerry, I am hoping to be done within the next 4 to 6 weeks, it is a simple build from now on, no complicated structures to build, just a case of decking out the hull with 1/2" oak planks, building a bench seat around the stern, which is where all the electrical bits will go, a 1" wide mahogany gunwale and a few crates. I am going to use Bowden cables to control the engine. No elaborate finishing, as I want it to look as tatty as it does in the film. Not sure about going to Coniston, bit far for me....

[Jerry C]

Hi Nick. It's a 4 day jaunt. We're taking the caravan together with 2 other couples. Already booked cos it's close to bank holiday. Anyway, you're halfway there already.
Jerry.

[kiwimodeller]

Nick I think you are going to need to find a water skier to tow behind it, never mind a Hepurn and a Bogart! I have a River Queen from Kingston (and agree wholeheartedly about the quality of Robins hulls) powered by the Graham Industries VR1A single cylinder version of your engine. It has a 2 & 1/2" reversable prop. On 30 PSI it will push the River Queen, which is larger than your Africa Queen, at way over scale speed. Have a look at it on one of our recent sailing days on http://youtu.be/tSjoT_bqvs0
What you see when it is going passed is probably at no more than half throttle. I think the TVR1A will make yours get up on the plane but I am sure you will get a lot of pleasure from her. Look forward to seeing her finished and on the water. Cheers, Ian.

[pettyofficernick]

Hi Ian, I am going to use a 2 1/2" prop with 3" pitch so I can run the engine as slowly as possible and still get max thrust, The advantage of running on low throttle settings, of course will be less steam consumption and longer run times. The AQ hull will displace a fair ammount of water, which should also keep the speed down.....

[Jerry C]

I got a figure from home and bargains. He's a member of some young boy band. I think you can do something with it. About 1/10th scale
Jerry.

[ooyah/2]

 Nick,
A well thought out steam plant, I like your oil separator combined boiler feed water heater, you will find that it will make a difference to fuel consumption, I think that Jerry did the same on his S.L.WEIR.
Congrats on the plant and no doubt the finished A.Q. will be great, look forward to seeing it completed

George.

[Mad_Mike]

hi nick nice bit of kit you got there. If your engine has 2 cylinders then technically the rpm would be half that of a single cylinder engine. presuming that kiwis and your boiler produce the same amount of steam flow and the same pressure constant. Im correct in thinking this right? I had noticed this characteristic when building my own engines.  If you do go over speed wouldnt it be just a simple case of turning down the gas to get a smaller flame, slowe steam production, lower pressure, more run time? It would be better than half throttling the steam valve then the excess steam blowing off threw the safety valve.   
 

[pettyofficernick]

The gas flow will be adjusted for optimum run times, however, I am not too concerned about the safety blowing off, as I have found in practice with my Victoria that it doesn't happen that often. The boiler feed pump will also be taking power from the engine, so a little more throttle is needed anyway. I have the Victoria down to a fine art now and get at least 35 minutes run time on one boiler filling. AQ will be replenishing the boiler as she sails, and I am using a much bigger gas tank (twice that of Victoria) so run times will be for as long as the gas lasts. With a steam plant, it takes a while to learn the characteristics of a particular plant, no two will be the same. Thanks for the compliments chaps, off to Home and bargin now to look for a suitable candidate for converting into Humphrey Bogart, thanks Jerry.

[tonyH]

Just as an aside, this is 1/2 of The African Queen on the plane. The real one, not the Hollywood one

[pettyofficernick]

The Hollywood one is still going, working out of Key Largo as a tourist boat, It was originally built for The East African Railway Company in around 1909.  http://edition.cnn.com/2012/04/30/showbiz/african-queen-bogart

[tonyH]

Aye, it's amazing how the story still raises a smile .
One day, someone will make a film, similar to The Sea Wolves but a bit closer to the truth, about one of the oddest of naval episodes. One of the original German target ships is still sailing on the lake apparently.

[pettyofficernick]

Next job is to make and fit a water inlet for the feed pump. This is just a short length of 5/32 copper tube, with a washer silver soldered in place to stop the tube falling through during the glassing process and a 5/32 pipe nipple for the silicone tubing to grip on. Once made it was glassed into place in the bottom of the hull.

[derekwarner]

Nick....it is little difficult to see from 22,000km away in OZ    ...but is the hex/round thingie...on the discharge side of the pump the check valve? ....Derek
 
Oh & BTW I like the yellow/black handled nut driver 
 

[pettyofficernick]

Hi Derek, there are two check valves on the pump, one on the suction side and one on the delivery side, arranged in such a way as to only allow flow in one direction. the flow then go's through a coil in the separator / condenser before entering the boiler via the clack valve.....It is nearly hot enough to brew up with once it has been pre heated in the seperator......

[derekwarner]

Hullo Nick.....in preparation for my build....I  have recently purchased two 5/32" OD tube inline check valves from Winfried Niggle [Germany] ....they appear to be approx. 0.8 PSI cracking pressure
I have no experience here in model terms and wonder if I should apply real values????
1. always install the check valves as close as possible to the pump S&D ?
2. by doing so eliminates the natural cushion effect of compressing the water at each pulsation if the valves were spaced some 25 to 30 mm away from the pump suction & discharge 
3. by installing the valves as close as possible could create load pulsations
Possibly a more experienced model steam engineer could offer comment.......thanks Derek

[ooyah/2]

Derek,
The hex/round thingie on the discharge side of the pump is a connection to enable a silicone tube to be fitted between the pump and the water supply and it's on the suction side not the discharge side.

Why do you need non- return valves on your water line.
Assuming that you have a clack in the boiler and your pump has ball valves on the suction and discharge side non- return valves are not necessary.

You would need some very large pumps and pipes to create water pulsing, this just does not happen in these toy steam plants that we build and are not necessary, you could have saved yourself some cash but keep the valves for a future project.
What type of boiler feed pump are you using?

George.

[derekwarner]

Thanks George
The nomination of twin check valves on  pettyofficernick's current build was his not mine.......Nick has not mentioned the design of this pump build
I am intimately aware of 380 Bar hydraulic pump or system pulsations & the consequences  .......but not of our 3 Bar steam scenarios
The question of pulsations was prompted by viewing images by Bernhard BB on Mayhem with his model steam launches with what appeared to be RENGINER  isolation valve accumulators on the discharge side of the servo driven piston pumps???
The design of my Saito Y2DR horizontal shaft engine makes the installation of the water pump worm shaft between journals difficult but not impossible .....Derek