ONE RUBBER POWERED KIT THAT REALLY BLOWS!

 

FOREWORD: Many thanks go to the author, Dr. Roger Simmonds from the UK who was so gracious to let me reprint it. He runs JETEX.org, and is editor of their house organ, SMOKE TRAILS. [Link at the bottom]

Jetex model flyers are much akin to we CO2 engine holdouts and record album enthusiasts inasmuch as trying to keep their interest functioning long after their products ceased to be manufactured. Keep the faith, brothers!

 

 . . Unfortunately, the model, ‘pukka vintage’ semi profile period piece though it is, is more than a little ‘agricultural’ and unappealing. A ‘turboprop’, then, is not such a good idea: is there a proper scale subject out there which features a jet and a propeller - one perhaps originally with mixed power units that fulfils my requirements. There is a nice modern design – Richard Crossley’s Curtiss XF-15C for rubber and Rapier L1 (Smoky Addiction 4) - but I don’t  know of any 50’s design with a diesel engine and a Jetex motor. However, there was one curious ‘dual power’ kit marketed in the US just after WW II:

The advert has appeared before in these columns (Smoke Trails 12). Ben Nead had wondered if the model was a figment of the copywriter’s imagination, as he had never seen one. Well now he has, and acquired one for his extensive collection of Ray models. Generously, he sent me scans of the plan and wood. At first sight, after I had pieced it together, the plan looked to be a very nice job, but closer inspection revealed some distortions and a 13 mm (½") disparity between the top (plan) view and the side view. Were these in the original, I wondered, so I asked Steve Bage to wave his magic ‘CAD wand’ over Ben’s scans. Steve writes: ‘The plan has an unmistakable ‘Ray’ look about it, and there are indeed a number of issues. The fuselage is significantly shorter in the side view than in the plan view and the printwood matches neither! I’ve stretched the side view a bit, it’s probably still a few mm short, but near enough for a toy airplane purposes. I’ve fixed the fuselage keels to match the plan view. 

It looks as if Ray had taken a paper copy, cut it up, and re-pasted all the bits together in a new layout, probably to make room for the photos. They used to do this quite a lot in those days. Some bits were not square and there were a couple of tell tale marks where things had been moved. The ribs also look rather an odd shape, but I’ve drawn them just as they are. Other than the fuselage keels I.ve not checked the print wood or die cut (or should that be die crushed) wood against the plan. I’ve squared up the bits best I can so I’m pretty confident that this version of the plan is better in a lot of ways than the original, but a few more ‘challenges’ will surely come to light during a build, so builder beware! Thank you Steve.

  

I’m sure Ray employed competent draughtsmen, note the fine perspective drawing below, and the inaccuracies are by no means unique to Ray. As any committed SAMmite knows, old plans can contain lots of errors which these days become very obvious when plans are ‘digitised’. Fortunately, correcting them in the digital domain is relatively straightforward. When building in the old days, I remember, we took these errors, distortions, etc, in our stride, ‘bodged’ our way around even quite large ones, and just carried on! 

About the design itself, Steve asks how one was meant to prepare and launch the ‘dual fuel’ model. Hmmm, a very good question, best answered by a quote from the (comprehensive) instructions: “First fly with the rubber motor only until you have the ship [sic] in trim. Now for a real dual power flight. Insert the rocket [CO2 bulb] in its tunnel and wind the rubber motor. One person must hold the plane in his right hand and with his left hold the propeller from turning. The second person carefully engages the gun squarely on the rocket unit. The person holding the plane gives the signal to fire the gun and launches the plane in a normal manner. The breathtaking climb that follows will give you a new thrill in model flying”.  

Despite the reservations, the Ray Fireball is a very nice design. Lindsey Smith is better able than I to assess its scale accuracy, but it looks good to me and one would of course (as Ray

themselves recommend) not bother with the undercarriage. It may be just the model I’m looking for. Reducing the span to 16-17 inches would make it suitable for one of Atomic Workshop’s little electric motors. They suggested a Voodoo15/25 with either a 90mAh or 130mAh LiPo (see atomicworkshop.co.uk). Building this vintage design essentially for electric power, I can incorporate a mounting tube for a Rapier, deepen the trough and cover it with foil. All initial flight resting would be under electric power, and a Rapier lit up as and when. Should make for a stirring sight! One thing still bothers me: I wonder just who was responsible for that name. Given the prototype had a very new and unreliable turbojet, the sobriquet cannot have inspired confidence in the test pilot. If we ever do see Rapiers again, and if they are as (un) reliable as the 2008/2009 varieties, any ‘authentically’ duel-powered Fireball could end up being just that!

LINKS

The original piece at Jetex.org - - - SMOKE TRAILS #27