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David Emery's Gilbert Erector Duplex Airplane Ride

Dave writes: "While browsing 'How To Make 'em' books from the '40s and '50s, I found myself suddenly reintroduced to the Airplane Ride model. It was one of the first action models I attempted as a youngster, and I remember being frustrated by the wind-up motor that would drive it only for a short time before running out of 'gas'. Several variations of this model appeared over the years that could be built with the smaller motorized sets. One version, driven by the A48 'wind-up motor', could be built with the 4½ set; other versions were powered by the standard A49 engine and could be built with sets 6½ and larger. But the basic theme was the same: four simple airplanes circling a short tower.

As I studied the drawings, it occurred to me that I ought to be able to design and build a much larger version with more planes and with more action. The result of my efforts, pictured here, is my 'Duplex Airplane Ride'. It stands 4' 6" tall and features two separate squadrons of airplanes. The inner squadron consists of six yellow-winged biplanes flying in a counter-clockwise direction around the tower; and the outer squadron consists of eight blue-winged jets flying in the opposite direction! The action of this model is absolutely spectacular!

The keys to proper operation are rigid tower and turret construction; use of the circa-1960 ball bearing system; gearing to create a proper operating speed (not too slow and not too fast); and balance. The model uses only standard Erector parts except for two elements. I have never cared for the P48 'mitre gears' because they tend to be 'jerky' under heavy loads. Therefore I used Meccano gears (a 25-tooth crown gear and a 15-tooth pinion gear) for the vertical power train that drives the "jet" turret. The resulting 5:3 speed reduction is also a better match for the model. The other non-Gilbert element is the commutator system I added in order to light the rotating turrets and airplanes. And I use hardware store nuts and bolts occasionally.

The 'power head' is driven by an A49 electric engine. The gearing arrangement is somewhat similar to that of the Musical Ferris Wheel Set's 'Radar Scanner': the inner turret is attached to an OH '72-tooth gear' driven by an P49 '18-tooth gear'. The vertical shaft, as previously explained, uses Meccano gears instead of Erector mitre gears. The only other oddity in my design is that I use two rare MP '24-tooth gears' outside the A49 gearbox to drive the power takeoff shaft from the "gearshift" shaft. This method produces the correct speed with a smoother power transfer than the OE 'flexible coupling' would permit.

There is nothing complicated about the tower. I used 16 MB '18 ½" angle girders' (eight lengths of two bolted together end-to-end), but obviously DP '12" angle girders' would work just as well. The turret arms are reinforced using wheels made of CS 'flywheel segments'. The inner turret has six arms and is constructed in a manner vaguely similar to the top of the original Parachute Jump; the larger outer turret also utilizes a CS flywheel as well as a circle of 11 newer-style EZ '6" curved big channel girders'. The turrets both rotate on standard BN turret plates using TB 'ball bearings' and TC 'retainer plates'. This is absolutely essential due to the weight and stresses while the model is in operation.

When I was a youngster I couldn't resist electrifying my models, and I had fun inventing clever ways to light up the moving parts. This model is no exception and the lighting yields a spectacular effect. In order to light the two rotating turrets, I had to devise two commutators. One consists of a disc made from copper-clad circuit board etched to provide a circular track against which a brass strip can brush; the other is a circle of E '2 ½" curved girders' concentrically mounted around the upper turret center and isolated by two pairs of nylon screws and nuts. The brass strips slide against the commutators, thus maintaining electrical contact while the turrets are in motion. The brushes are springy brass strips bolted to BY 'fiber strips'. The model frame provides the return connection. I added lights to the ends of the tower arms and I even electrified the planes themselves.

Using thin and flexible 22-gauge stranded hookup wire instead of string to suspend the planes, I was able to make an electrical connection from the turrets to the airplanes. Using tiny red and green Christmas bulbs, I was able to add the running lights to each biplane wing (red on the left, green on the right). On the jets, however, I placed orange/yellow lights inside the W 'stacks', representing the jet engines, which are mounted under each wing. I covered the front end of each W 'stack' with black electrical tape so light was visible only from the rear, as jet afterburners would appear. I could have added jet running lights as well, but I didn't. If you don't want to cut up your Christmas lights, Radio Shack offers blister packs containing red, green and amber 6-volt miniature bulbs that are perfect for this project.

Doc's Note: Dave chose the wire and commutator method for lighting his model, and he got great results. To see an alternative "wireless" method for lighting similar models, check out my own Rocket Jets Ride here in the Model Gallery.

This model was fun to design and build, and there is considerable satisfaction in thinking up an idea like this one and seeing it through. Other builders can undoubtedly improve on the design mechanically and aesthetically, and I hope that seeing this model on Girders and Gears will provoke some thought and enjoyment as others build and refine it."