About this Plan
Multiplex Flamingo. Radio control sailplane model. Wingspan 2560 mm.
Quote (from ad in MB July 1982): "Multiplex Flamingo. Excellent for FA1-F3B competition and all around flying as well as thermal duration. Proven design. Quality of kit must be seen to be appreciated. Eppler 193 airfoil. Wingspan 100.4 in. Epoxy glass fuselage. Built up wings and tail group. Ailerons standard (spoiler and/or flaps optional)."
Note the planfile includes Addendum (in German) and decals.
Direct submission to Outerzone.
Update 18/08/2020: Added kit review from June 1982 Radio Modeller, thanks to RFJ.
Quote: "PM Rundle reviews the Multiplex Flamingo. A 100-3/4 inch span soarer designed for F3B use, distrubuted by Sailplanes International.
MULTIPLEX'S FLAMINGO is a 100-3/4 in span, aileron equipped soarer. It has the option of variable loading by ballast tubes in the wings, and air brakes. It is obviously designed for F3B, but also has a lot of potential for off the slope flying.
I had my eye open for one of these ever since seeing one at the 1980 Nats at Cranwell. So it was with great delight that I received the Flamingo to review.
Open the Box! The fuselage is a beautiful epoxy glass moulding and took up a lot of the box space. The rest of the box was packed with a lot of superb quality balsa, and many polthene bags full of fittings, etc.
The wings of the Flamingo are built up and sheeted and I welcomed the change having only worked with foam and veneer lately. The die-cutting of the ribs was the crispest I've ever seen. The few plywood pieces, however, needed a helping hand and luckily I had access to a friend's jigsaw.
The Wings: As the Flamingo's wings are fully built up sheeted structures, they provided most of the actual construction work. Even so, they built very quickly, the first wing panel taking three evenings to complete.
The first job was to make the skins. This was simply a case of butt joining three pieces of three inch sheet with white glue and leaving them pressed flat over night. It was here that I found the only mistake in the instructions. These stated that the upper surface of the wings should be sheeted in 2mm balsa and the underside in 2.5mm balsa. The sheeting supplied in the kit was 2mm and 1.5mm. Anyway a quick look at the plan showed that the underside sheeting was thinner than the top, so I presumed this to be 1.5mm.
The two upper main spars of the wings are constructed by laminating two strips of hardwood, the lamination only being at the root end of the wing.
Great stress was placed on the fact that the air brake snake took a different route in each wing due to the devises locating on opposite sides of the output disc of the airbrake servo. So great care was taken in drilling the right holes in the relevant ribs for each wing.
The next job was to construct the wing mounting blade boxes. Again these were different for each wing since the blades overlap in the fuselage. But if the instructions are followed no problems arise.
I decided to fit air brakes (these are not supplied in the kit) and happened to have a set waiting to be installed in something.
Die cut pieces of balsa were knocked out of the relevant ribs and the air brakes were just glued in. The bellcrank for activating the airbrake was mounted on a block and glued in, as was the bellcrank for the ailerons. I feel I must comment on the aileron bellcranks, as these are superb. There is absolutely no backlash in the system at all because the clevis pin is silver steel, which runs in brass bushes in the bellcrank. The bushes are first pushed into the bellcrank where wanted. The pivot of the bellcrank is similar. The aileron push rod was made and installed in the wing. The ailerons are cut out when the wing is completed.
After the wings were sheeted, the airbrakes were located by probing with a pin and an aperture cut for them. They were then capped with a strip of balsa and sanded until it was exactly flush with the wing when closed.
Fuselage and Canopy: The epoxy fuselage in this kit was a joy to work on. There was no trouble encountered when drilling holes as one often gets with polyester resin ie chunks of gelcoat flying off leaving jagged hairy holes. Drilling epoxy is more like boring holes in hard soap.
All the holes that had to be drilled in the fuselage were clearly marked as indentations in the moulding so a really accurate job would be done. The only bit of difficulty I had was to fit the spring washers each side of the bellcrank inside the fin, getting the bearings through these without them dropping off. In the end I glued them to the bellcrank with super glue, attached the snake inner with a clevis, pushed the whole unit into the fin and then glued the bearings through from each side. I then cracked the spacing washers off each side of the bellcrank with a small screwdriver. There is probably a less diabolical way of doing it, but this worked fine.
Wing mounting is achieved by a clever device formed from two pieces of brass box section, two ball bearings and a spring clip which has adjustable tension. This was assembled according to the instructions on the box. The dihedral angle was set by two sliding brass collars and the whole unit liberally coated with epoxy. Holes for mounting this device were then drilled and filed in the wing roots, these again being clearly marked. The wing mounting was then persuaded into the fuselage and trimmed to the right length. To get the mounting into position it was necessary to enlarge one of the holes in the wing root section, but this was easily filled in later on.
One tricky little job was to glue in an anti-crush plate between the rear position of the fuselage wing stubs. This was to stop the fuselage collapsing if the model came in hard on one wing tip. The trouble was that it was mounted well back from the cockpit opening. Good or super glue came to the rescue again. I glued a strip of balsa to the edge of the plate, liberally applied epoxy to the ends and pushed it up the fuselage until it got wedged at the right spot. When the epoxy had set the strip of balsa was just snapped off due to the brittle qualities of super glue.
Radio installation was also straightforward. My servos are the same size as those shown on the plan so the plates were cut accordingly. One thing dismayed me slightly in that with the aileron and air brake servos and mount in the right place, the mounting screws for the servos are totally inaccessible. I elected to mount the servos on the plate and lightly glue the plate in the fuselage, so that the plate could be cracked out if necessary. The differential output unit for the aileron servo was made from a piece of 1 mm Perspex.
Rudder and All Moving tailplane: Both these structures were of built-up sheeted construction, the final units being extremely light, being sheeted with 0.8mm balsa of very fine quality. The kitting was so accurate that when the halves were assembled onto the fuselage, they would drop off under their own weight. The dowels had to be bent to provide some friction.
Covering and Finishing: Because I was keeping weight to an absolute minimum I decided to cover all the flying surfaces with iron-on film. The fuselage was sprayed with aerosol car touch up cellulose paint, after a few very small air bubble pin holes had been filled with cellulose putty.
All that remained was to attach the ailerons using the extremely sticky white tape supplied, and to run around the air brakes with a knife blade to free them.
Trimming and Flying: With my trusty Micron R/C gear plus a 600 mAH Ni-Cad pack installed, the centre of gravity fell within the range specified in the instructions, but towards the rear limit, so a small piece of lead was added to the nose to bring the CG to the quoted optimum point.
Well, with the model complete and ready for it's first sortie I waited with Ni-Cads fully charged for the coming weekend, only to be buried by snow. I could not get out of my home let alone go up the slope, so I had to play a long waiting game.
Anyway, weeks later the road was opened, the wind was right, so I could have a real flying session. With my adrenal glands over-worked the Flamingo was bunged off into space. After a panicky fumble with a bit of up trim (I'd fed a bit of down in because it was quite windy), up she went like a rocket. Being quite slippery the Flamingo penetrates very well even without ballast. The whole impression of the aircraft is of smoothness and is totally untwitchy. Turns like a bit of rudder and the ailerons are quite sensitive for small adjustments around vertical but need to be used heavily to get a nice quick bank. Pylon race-type turns are beautiful to do, she just grooves round maintaining height and speed. Magnificent stall turns are possible, she just goes up and up and kicks over nicely at the top due to a very effective rudder. I tried stalling; this was very gentle, no wing dropped and no real appreciable loss in height - she just dipped her nose.
Well, after setting down and flying around a bit I had to try the inevitable landing. On trying to land one can see why the Flamingo is fitted with air brakes. I tried the first landing approach without them and anyone who has done much flying knows the problem. A bit too much down and the model accelerates, a bit too much up and the model climbs. Consequently my first approach was about 50 ft up.
With the air brakes out, the nose tips gently down and when this is corrected the Flamingo mushes in very nicely with no horrid acceleration. The trick is estimating the landing approach so the model lands vaguely near you. I'm getting a bit closer each time.
My next outing with the Flamingo was in marginal conditions but I had no trouble maintaining height and climbed with a couple of thermals, even with my atrocious attempts at climbing turns. As yet I have not tried towing her up on a line but this is destined for the very near future.
Conclusion: The Multiplex Flamingo, although aimed at a specialised type of competition, makes an ideal general purpose soarer. It seems to have no vicious tendencies at all and is ultra smooth to control. The Flamingo will make a nice soarer to scratch around with on those nice balmy summer evenings on the slope.
I don't think that anyone who has built a couple of models would have much difficulty building the kit as long as the instructions were followed. Distributor: Sailplanes International, Cwmtillery Industrial Estate, Abertillery, Gwent. Price £65.50."
Supplementary file notes
Catalogue page (in French).
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User commentsWhere can fiberglass fuselages of these gliders be purchased? Great kit gliders have glass fuselages Eg Cirrus so it would be nice to be able to get hold then to build per original.
Peter - 17/08/2020
If you ask on a forum like rcgroups.com or rc-network.de you may find an unused one or a source for new ones but the market is not really there so you may not find one. Otherwise you have to make your own. I would suggest lost foam technique for a one off.
Martin Hodgson - 17/08/2020
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