Spitfire IX (oz12404)

About this Plan

Spitfire IX. Radio control scale model fighter, for Speed 400 motor.

Quote: "Free Plan. This month we treat you to another of Adrian's classic fighter plans. Supermarine Spitfire Mk IX, by Adrian Britton.

As you may have seen from the December issue, I knocked up a little Spitfire and took it along with my 40 4-stroke powered P-51D to Eastnor just to add to the flightline content. When it came to the safety inspection rounds, the Mustang was thoroughly scrutinized. Then, as the guy labelled it green and started to move on, Mary picked up the little Spit from the grass by the foot of her chair with two fingers and, holding it up, said: Don't you want to check this one, we are hoping to have it flown? He looked at it as if it were a kid's wind-up toy plane from Woolworth's 1952 and said laughingly: There isn't even anywhere to stick the label!

Later on Tim Whitcombe, the highly polished Ace Barnstormer of our Club, Gaer Park MFC, flew it in the morning slot - a lot of it at about 6 inch altitude! In a later slot my scruffy old tranny was being passed from pillar to post! Nobody seemed interested in my P-51.

The model was a Mk IA in brown and green and your Editor showed a lot of interest - along with Cambrian Models. Jonathan of Cambrian has kept it for examination with a view to designing mouldings etc, for eventual kitting and I'm working on the drawings and words for that project.

I soon began to miss my 'toy' fighter and so apparently did your Editor so I started doing another one, this time as a Mk IX. I liked the original and historic film star aircraft at Duxford (MH434) so I went for it. See The Old Flying Machine Company's website www.ofmc.co.uk. The Spitfire is part of their Breitling Fighters collection. I may well be modelling the rest of them this way in the future.

So this plan is of the new Mark IX version, slightly larger at 27 in, but with the same 400 motor and even better to fly with lots of performance coupled to smoothness and stability.

Build The Spitfire: Everything must be light but strong, especially rear of the wing on the Spitfire. I discovered how to print on wood from my own parts drawings. I printed them on to some A4 transparencies and 'transferred' them onto the wood. Then they were very carefully, ink down, laid onto the wood, held down steady and lightly pencil rubbed. I had a good old-fashioned set of printwood sheets - just like vintage kits! I believe this is possible to do with photocopies.

The Wings: Build a complete wing first. Start by looking at all the relevant pictures and areas of the plan. Prepare the 1/16 bottom sheeting from the patterns. Butt-join (using the 'tape together and glue' method) and lay down the centre section first. Pin and glue the 3/32 sq lower spars exactly in position, using a rib as a guide. Pack up under the LE and fit all the RI ribs for this panel, they must be vertical, especially the outers. Chamfer along the edge of a length of 3/32 x 1/4 and fit it as the primary LE. Add the top spar. Chamfer the top of the LE to accept the top 1/32 sheeting. Add this, but only to the middle of the top forward spar for now.

The main panels can be completed to the same stage the same way, but angle the root ribs with the template. Pack up under the trailing edge towards the tip a little when sheeting the LE up to the spar (as before). This will assist when setting the washout later. If you feel you need to reinforce the dihedral break with gussets, webs or a light brace, go ahead, the prototype didn't need it by the time the joint was tissued, and doped. Follow the photos and plan sketches regarding the aileron and sheeting stages. Make up and use the washout/dihedral jig when joining and sheeting the rest of the wing. The final result should be zero incidence at the tip rib position (in line with the Tailplane). Make sure of this before finally gluing the wing in place.

The Tailplane: Construct the Tailplane and Elevator assembly. This bit is straightforward enough on the plan. Now, here, I went a little overboard and built these up using a 1/32 base with 3/32 for the top with the elevators made up of the 3/32 scale shaped LE and 1/32 strip for ribs. I even cut away the trim tabs! Anyway, sand, tissue and dope it. Make up an over length pushrod from stiff 1/8 sq and the 20 g wire connecter bound to it and locate in elevator horn. Leave the other end until final assembly with the servo in place. We can't afford the weight penalty of hardwoods and adjustable linkages!

Fuselage: Construct the fuselage crutch frame, add the formers from F2 onwards, the 1/16 sides (note that the tops of these butt up against the bottom of the crutch becoming flush with the fuselage sides). Add the tailplane mounts and the 3/32 sq spines. Make up the 1/32 sheet rolled motor tube and fit with the correct thrustlines. Stick the little 400 in to help you here. Add F1 and the laminated nose block and 1/32 ply ring so that the motor will slide in and out as needed. Shaping up can be left for later, Just get that shaft pointing out of the right place!

Final Assembly: Get the fitting of the wing and tail organised and aligned. Fit and set up the aileron servo and connecting rods. Operate them and pre-adjust to get about 5/16 up and as little as possible down. Now glue the wing in position. Slip the elevator pushrod (with the tail hanging about on the other end) down through the fuselage (remove the crutch cross members carefully where they interfere). Attach the tail assembly. Install the elevator servo and set up to achieve a maximum movement of 5/16 in up and down. Even at this size Spitfires are notoriously elevator sensitive! A drinking straw aerial tube can be inserted as well.

Add the sheeting and planking. Make up and fit the fin and rudder. I went mad again and made it work too. It doesn't really need it - it's up to you. I'll talk about it later! Make up filleting from paper. Sand everything to perfection, dope, sand again and cover with light Jap type tissue doped on. Make sure that the foam wing filleting is well sealed under the paper with PVA so that the dope can't attack it. Add your exhausts, guns, aerial mast etc and lightly airbrush or paint the model and add the insignia of your choice.

I made a cockpit canopy by heat shrinking the centre section of a pop bottle around a plug packed in tight. Sticky backed peel-off label paper was cut into I mm strips, painted, peeled off and stuck on to the canopy moulding. The canopy is only glued to the removable section of the fuselage.

If you are going to detail the tail feathers job and connect up rudder etc, do bear in mind that built-in lightness is essential on an electric aeroplane. Also any model Spitfire is prone to tail heaviness. I only got away with it by virtually butchering the inside rear fuselage and praying throughout the building and finishing time! I also made no attempt to keep anything up front down to a weight following this. I don't as yet have the patience or skills for airbrushing which would look far better at this size. As it turned out, the model flew great - but I haven't used the rudder yet! It's still too cold for me to go out again like some of our brave Gaer Park boys!

Flying: (max wind speed 10 knots) My model turned out at 14 oz, which is a bit more than I wanted, but I am not a perfect builder. The CG must be well forward of where you would expect (as shown on the plan), but you may be able to play with this as you go. I've only had one maiden flight so far and it was fine as far as I could tell despite all that wind to contend with. I rolled and looped it and generally put it through a good 'schedule' but it got too cold to continue. It was gusting at about 15 mph when I brought it in awkwardly but safely after about seven to eight minutes. I was quite pleased - pleased enough to go and get my award - a pint in front of that big fire down at the Lighthouse Inn at St Brides.

Right! Now its your turn! The 9.6V AAA NiMH pack from Overlander gives plenty of constant power and flying time, so there's no need to go for height or rush straight into aerobatics from launch.

With everything as per plan and all the above plus centred controls, have it launched level, without too much effort, with full power on. The model should accelerate strongly and climb. You should now need to back off the power a fair amount to trim it out and stooge around. It can go fast enough to easily hold its own with the big boys if you want, but don't let it get too far away from you. Shut down the power at the top of loops and when diving,

To bring it in, allow the model to descend on throttle control all the way to touchdown, then shut down and flare. Don't try to stall it in, I haven't found out yet how it will react! On the other hand, if you do try it, let me know what happens.

Right. That's it! There's another model to draw up and build - I'm not sitting here anymore, I'm going to make another fine mess in Mary's dining room! All the best to those who dare!"

Direct submission to Outerzone.

Note photos [main pic, 003, 004] of completed Spitfire IX model by FlightEngineer were found online at https://www.rcgroups.com/forums/showthread.php?313041-Please-post-your-spitfire-picture/page2#post3500552

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