B.B.

Ball Bearing Lightning

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STUART B.B.

Fully machined set of castings and parts with all bolts, nuts and screws, full instructions and drawings ….. 21/- post free.

Ditto, with all holes accurately drilled and tapped …. 30/- post free.
Machined Box Bed and 4 bolts, 2/- extra.

FINISHED ENGINE, built in our workshops, and tested under steam …. £3 post free.

Fitted with drain cocks and cylinder lubricator, 6/3 extra. Mounted on box bed, 2/6 extra.

Foreign orders should include Postage for 2-lbs.

The following parts, which are optional, can be supplied post free :-
3 drills, 3/32-in. and 5/32-in. clearing, 3/32-in. tapping, 1/11; Taps, 3/32-in. and 5/32-in., 9d. each ; Pin Drill, 3/32-in. each, 1/-; Hardened Steel Spanner for 3/32-in. Nuts, 1/-; Pair of Drain Cocks finished, 4/- ; Single Cock Cylinder Lubricator, 2/6 ; Steam Pipe and Union and Exhaust Pipe, 3/6.

Machined parts can be supplied individually at the following prices :-
Cylinder, 3/- ; Top Cover, 1/- ; Bottom Cover, 1/6 ; Piston and Rod, 1/- ; Valve Chest, 1/6 ; Valve Chest Cover, 6d. ;Valve, 6d. ; Valve Nut, 3d. ; Valve Spindle and Head, 9d, ; Gland, 6d. ; Crosshead, 1/6 ; Connecting Rod, 1/6 ; Crank Pin, 1/- ; Eccentric Rod and Strap, 2/- ; Eccentric, 1/- Crankshaft, 3/- ; Ball Bearing, 3/6 ; Outer Bush, 1/- ; Aluminium Body, 10/- ; Door, 1/- ; Flywheel, 2/- ; Lagging, 4d, ; Instructions and Drawings, 3d.
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STUART B.B.
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¾-in. Bore x ⅝-in. Stroke.
Height from bottom of Crank Case, 4½-in.
Weight without Flywheel, 17-ozs.
Weight of Flywheel, 4-ozs.
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A ball bearing, enclosed, high speed engine, with aluminium crank case, for the heaviest duty and continuous running.

Specially designed to the utmost efficiency at the highest speeds, and absolute reliability for racing model boats and direct coupled electric generating plants. It will appeal to the racing expert who must have the best engine money can buy, and equally to the beginner who wants a simple engine, easy to build.
The design is such that the very finest limits of accuracy can be and have been observed in machining the parts which are all interchangeable - really interchangeable. Each part is made of the material best suited to its work. The ball bearing gives practically everlasting wear and ensures that increase of power, due to increase of pressure and speed, is not absorbed in friction.
The enclosed aluminium crankcase means lightness, cleanliness and perfect lubrication, and its graceful lines make this the most handsome engine on the market. Being in one piece, perfect alignment of cylinder, guides and crankshaft are ensured. It will be noticed that the crankshaft is balanced and the crank pin is of large diameter to reduce wear and made hollow for lightness.
We have run this engine for hours at 4,000 revs. per minute under a pressure of 70-lbs. per sq. in., and after the most severe tests can discover no sign of wear.
The engine can be built without a lathe. A few drills, taps, and files are the only tools necessary. For those who have no means of drilling, the set can be supplied with all holes drilled and tapped. This is done with great accuracy and saves the expense of purchasing special tools.

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B.B.
Direct Coupled Plants
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The B.B., being a very high speed engine, is most suitable for direct coupling to a dynamo or centrifugal pump. Special bases for this purpose are shown on page 60. The pump is on page 27. The plant can be built without a lathe. As illustrated, finished and tested in our works,
£4 10s. 0d.

Design

This engine is a departure from the normal Stuart engines, most noticable in its futuristic looks. The use of aluminium for the main body allow for a nice highly polished finish. The Cylinder is of an oversquare design where the stroke is shorter than the bore, this imcreases the speed at the expense of power. The rating of 4,000 rpm makes it ideal for a dynamo or pump. Both of which were catered for with baseplates to fit already available units. The crankshaft ran in a Ballbearing hence the BB name, reducing wear and allowing the fast operating speed, A large hollow crankpin and counterbalances crank, also improved speed. The closed crankcase allows for wet sump lubrication. Partially filling the crankcase with oil allows for the crank to splash oil all over the crankshaft, bearing, trunk guides, and bottom of the piston lubricating most of the cylinder. This extends to the outside of the crankcase as the eccentric is mounted in an extension bath. The crankshaft leaves the bath through a bearing point lubricated by a pressurised grease fitting. (similar to the grease fitting used on the water pump shaft to prevent leakage.) The effect of all these design features is an extremely smooth running engine and free running engine. Almost no vibrations even when running at high speed.

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Stuart BB + Bottone Generating set.

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Stuart advert. Yes this was a surprise to me.