About this Plan
Precedent Fly Boy. 3 channel Radio control trainer for 2.5-4cc motors. From Balsacraft, which closed down in 1999.
Quote: Fly-Boy has been designed as a beginners model using low cost 2 or 3 channel radio control equipment and economical 15-25 sized engines. The basic controls are the rudder and elevator, throttle control is optional. Before you commence construction, take some time to study the plan and isometric assembly drawings. They have been designed as a package as there are some stages which are better covered, for example, in the written instructions than can be shown on the plans.
Use a good quality PVA or aliphatic resin adhesive (WHITE BOND) for all joints unless otherwise stated. You will also require a small quantity of fast setting eqoxy resin adhesive, some balsa cement and some contact adhesive. Always use abrasive paper either wrapped around or stuck onto a flat block, a fold of paper held in the hand is often worse than useless! Identify all the parts either from the die-cut sheets or by reference to the parts list. there is ample material supplied provided you follow the cutting instructions carefully. The parts are numbered in the building sequence. Most of the construction of the model is done over the plan: This should be laid•onto a flat building board (we suggest a piece of blockboard about 1000mm x 300mm x 18mm) and covered with a clear polythene sheet to prevent glue sticking to it. You can pin down assemblies using ordinary steel dressmakers pins tapped lightly in with a small I ammer and remove them when dry with pliers.
CONSTRUCTION: Pin down the fuselage sides 1 and glue the various longerons 2-4 in place. Also glue the tailpost 5 to ONE of the sides. Drill the fuselage sides where shown 1/4 in diameter (6mm) for dowels 41. Measure the width of your motor and trim the engine beares to suit. Note that the bearers are slightly tapered to offset the motor to the right, this angle is IMPORTANT and must be maintained. When satisfied, glue the bearers 6 and 7 to the right and left sides respectivly. Drill formers 8 and 11, 4mm (5/32") for throttle tube 65.
Pin the right fuselage side down flat between X and Y (see Fig 2) and glue parts 8-10 in place. Trim the bearer slots in part 11, if neccessary, and glue this in place. Ensure it is exactly at 90° to the fuselage side by checking with a set square. When dry, glue the other fuselage side in place over the first, weighing down the assembly until thoroughly set. Pack up the extreme rear end of the fuselage with jig piece 12; draw the other fuselage side down onto it trapping former 13 in its slots and glue. Allow to dry then remove the assembly from the board.
Taking the right side first, glue part 14 in place right up against former 8. Leave a 4mm gap and glue one of the parts 16 in place. This will form a slot into which the upper part of the undercarriage leg 67 will fit. Because the legs are staggered one behind the other, part 15 is 4mm narrower than part 14. Glue this in the corresponding position on the left side, again leaving a 4mm gap between part 15 and its own part 16. A quick look at the top view of the plan should clear up any confusion here. Cut away longerons 4 where the slots occur to clear the legs.
Locate and glue in place the tailplane seat 17. Clue the two undercarriage mount pieces 18 and 19 together, leaving the punched holes in part 18 showing on the underneath and making sure that part 19 is central on part 18. When dry, drill through the holes with a 5/32 (4mm) drill. When offered up to the fuselage, these holes should align with the slots formed by parts 14 & 16. When you are satisfied with this, glue the undercarriage mount assembly onto the fuselage, hold in place with adhesive tape while the glue dries.
Using a flat sanding block, smooth the edges of longerons 3 and 4 level with the sides 1 to remove any glue which may have oozed out and set. Cut a piece of 3/32 (2.5mm) balsa sheet 3-1/4 (84mm) long and glue it immediately behind part 18 with the grain running across the fuselage. Continue cutting and fitting the lower sheet 20 in this way until you reach the tailpost. Similarly sheet the lower nose with 1/8' (3mm) balsa 21 between parts 19 and 11.
Place your engine between the bearers and mark the position of the mounting bolts. Drill through 1/8 (3mm) and counterbore up from underneath 4mm diameter, 4mm deep (5/32 in). Locate the engine and push the bolts through from above. Thread on the spike nuts and tighten until the spikes bite into the wood and are held firm. Smear some epoxy glue around the nuts and, when dry remove the bolts and the engine. Add the doublers 23.
At this stage you are best advised to fuel proof those parts of the engine and tank bay which you will be unable to reach once parts 24-27 are fitted. You can use various commercial fuel proofers for this, our own preference is two coats of Tufkote. Don't forget to give this treatment to the inside of parts 24-27 too. Pay special attention to this - if you allow fuel to soak into raw balsa it will rot it very quickly.
Sand doublers 23 absolutely flush with sides 1 and glue bottom part 24 in place. Also fit parts 25-27, sand to shape when dry by reference to fuselage side view on plan. Sheet the upper rear fuselage 28 with 3/32 (2.5mm) balsa as for part 20. Add the wing seats 29 from balsa strip. At this stage you should sand the finished fuselage smooth and round off the corners, referring to the sections on the plan. After removing all dust by brushing and blowing, we can proceed to cover the fuselage. We recommend a heat shrink film such as Solafilm, following the instructions supplied with the film.
The engine bay should be painted and fuel proofed. Leave the tailplane seat 17 uncovered (as glue will not stick to film at all) Rub glue into the ends of parts 30 where the tips 32 will fit and allow to dry. This is known as 'pre-glueing' and prevents the glue used for the final joint being drawn into the end grain balsa before it has time to make the joint.
Pin down the main panel 30 and fit the leading edge parts 31 and tips 32 (cut from 3/16 x 1 in- 4.5mm x 25mm balsa strip) When dry, remove from the board, sand smooth and round off the tips and leading edge as per plan..."
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Note: Googling this kit for reviews suggests very mixed opinions, including for example: 'a pig' and 'awful'.
Update 09/08/2014: Added instructions, thanks to James.
Supplementary file notes
Instructions text 7 pages, inc layout drawing, thanks to James.
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User commentsNotice the formers have been penciled in. The secret to a square fuselage is the servo tray, which isn't drawn, but can be worked out from the plan. Despite the self jigging fuselage, use of a jig like the SLEC fuselage jig, is recommended. Hopefully someone will post the T240 plan one day. Regards,
Marty - 10/04/2014
Dear Steve, I've scanned the instructions for the precedent Fly-Boy to go with the plan currently uploaded on your site. In addition to vital information such as control throws and build sequence it usefully includes a complete parts inventory containing the measurements for all wood parts required. I hope someone finds it useful. When built correctly the Fly-Boy flew very well.
James - 09/08/2014
The former outline marked A1 is incorrect as it should have engine bearer slots. Also the dihedral brace is wrong as the model has no centre section.
anon - 15/08/2017
Hi - I just wanted to add a bit of info about the Fly-Boy as I learned to fly with one of these in the mid-nineties, flying it probably around a thousand times if not more. I also flew two others. Mine was powered by an OS.15 which was more than enough power, I also flew one powered by a 'hot' 25 and another with an OS.35 in the nose. With the OS.35 it was heavy and the most powerful version I flew was by far and away the worst handling of the three. The version powered by the OS.25 was also overpowered and more of a handful than the 15 powered example. As a primary trainer this is not a great design, it has a habit of snap rolling at any speed if excessive elevator is used (even with the prescribed throws), it also spins like a top. As a three channel aerobatic model it was very capable though, the only thing that it struggled with was sustained inverted flight but it would roll very well just on rudder, looped smartly and spins were easy to enter and recover from. It could be flown slowly but great care had to be taken with the elevator, if stalled at low speed and in any sort of turn, it would spin straight in. Structurally there are a couple of points that could be improved: The arrangement of the fuselage with plywood pre-cut panels featuring those big open areas aft of the C of G isn't great when covered with iron on film. There's too much movement in the structure and no matter what, the covering over those parts of the fuselage will sag and require re-tightening on a fairly regular basis. If building one, I would put in some diagonals to stiffen these areas up and provide additional area to stick the covering to. 1/8th square would be adequate and add very little weight. The undercarriage as designed is also a weak point. It will spread and splay. The version I flew with the 25 in the nose was the second example built by the owner and he had added a second undercarriage leg and a rubber band bungee arrangement. This was a massive improvement. Build this one as light as possible, don't overpower it and you'll find you've got a fun, if snappy, three channel sports model. If you want to learn to fly from scratch, build a Super Sixty (just beef up the centre section braces if you do go that route)! Hope this helps somebody.
PeteT - 21/08/2017
Photo of completed Fly-Boy was found online at https://extreme3d.wordpress.com/2014/09/06/24-balsa-flavoured-wings/
SteveWMD - 21/08/2017
I learned with a Fly-boy, great plane very good flight (pretty nervous) but good memory !
Elven - 28/01/2020
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