Alex Whittaker twangs on his Marigolds and gets to grips with cleaning up a much loved but tatty sports model.
Most radio modellers are ‘Airframe Retentive’. I have had always had trouble throwing out old models, partially pranged models or those high-hours airframes that just need a little tender loving care. Like Darling Greta, I do want to save the planet. Mainly so that I can carry on flying endlessly repairable, eco-friendly balsa wood and glow plug engined models.
There is something really satisfying about combing through your Old Flames and finding an old favourite to refurbish. I did this recently, as I have done many times before, with an elderly but still superb glow model. To my delight I found that under the accumulated oily muck and grime the covering was still serviceable.
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Good, because I chuffing hate re-covering any model and loathe the intermediate process of removing the old film covering. So, this refurb was an instantly attractive proposition. However, in a number of other areas my high-hours baby was not quite airworthy…
CLEANING & DEGREASING
First of all, she needed cleaning down, plus a good dose of looking at.
My de-greasing kit comprised:
• Paper towels for all wipe downs
• Baby wipes for the sheep muck
• Methylated spirits for the oily bits
• A well-worn kitchen sponge pad for very light abrasion
• Mr Muscle Kitchen Cleaner
• Talcum powder
• 800 sandpaper
The baby wipes were used for the first rough wipe down and then I sprayed the kitchen cleaner on the grubby and still cloudy film. This worked wonders and I wiped it off with other baby wipes, then dried it down with kitchen towel.
Stubborn grass and mud stains near the undercarriage on the lower wing were treated to the soft sponge treatment with meths. Once finished the film was given a light polish with dry paper towels. The finish was much better than I expected.
Next task was to remove the original foam wheels, since two had developed flats. At this point, with meths and baby wipes, I degreased the piano wire tricycle undercarriage.
I fitted larger air wheels, which, from experience, work well on our upland sheep farm grass. I replaced all the wheel collets and washers.
RX PACK UPGRADE
I threw away the old pack and fitted a 2000 mAh version. Out of prudence, I also replaced the battery / charge switch and checked the integrity of the Rx wire aerial.
There were various little airframe jobs to expedite. I added a few tiny screws to toughen up the (apparently sound) high-hours engine firewall joint.
The tailplane seat was a bit loose so I eased it off with a new scalpel in my knife and dusted the newly exposed area with lots of Christmas talc to remove as much of the oily residue as I could from the balsa.
I used baby wipes and a bit of light sanding to clean up the immediate joint area, to better key the fresh glue line. I reset the joint square with heavy weights as the 10-minute epoxy glue dried. To my slight surprise the result was excellent.
The fuselage and wing-seating areas were thoroughly degreased with meths, baby wipes and talc. There was no serious damage, but I upgraded the wing retaining nuts to new captive types.
I threw away the existing Phillips head set screws and fitted new Allen key set screws. I had toyed with the idea of easy snap-off nylon types, however I reasoned that since she had flown all her high-hours with metal bolts they could remain. These latter Allen key jobs are much better ‘field serviceable’ items.
I put bigger plastic washers, backed with steel ones, onto the new wing retaining set screws. This was to pad out their footprint on the lower wing. These simple upgrades made the whole wing fitting much more rigid. I added some new wing seating tape whilst I was at it.
The wing locating slot, lost in the oily fuselage, was in good order and did not need any beefing up. This is something I have had to do in the past on other high-hours models.
Any steerable nosewheel takes a huge pounding and many hours of my dodgy landings had rendered the original terminally wonky. It was held by a collet, retained by a grubscrew, which by now had about ten degrees of slop.
After some thought I decided that it was easier to fit a new engine mount and steering arm but retain the original piano wire. I used a Nexus steering arm, drilled out a bit bigger at the collet, and then tapped for a fatter grub screw. This was to give a bit more strength to take up the slop in the slot on the original piano wire.
I ground a bit more flat on the undercarriage piano wire to accept the bigger grub screw. This meant disassembling the whole nose area, but it was worth it.
In fact, such methodical bench work can be oddly therapeutic. It was a lovely finite ‘get-the-job done’ weekend project. Whilst I was at it, I fitted new captive nuts behind the new nylon engine mount inside the fuselage.
The radio installation was in good order, but I did replace all the connectors on the servo arms, as well as the aforementioned Rx battery / charge switch.
I was amazed how well a simple plywood servo tray had taken the hammering over the years.
Since I had the engine out on the bench, I gave the outside a lick and a promise. However, I did check over the carburettor, which had served me well for many a moon.
No immediate issues came to light on this perfunctory engine inspection, but I was glad I bothered. I put on a new prop and later changed the spinner from plastic to alloy.
The tank was oily but sound, so I decided to replace all the plumbing. This is cheap and easy with silicone tubing and it gives you peace of mind. However, it is important not to over tighten the tank sealing bung. It is also important to cut the new smaller gauge internal clunk line to such a length that it does not foul the back of the tank wall in any flight attitude.
I used three bits of brass rod soldered together to pull the vent, fill and carb silicon tubes thorough the firewall. Or you could just use a short piece of 250V AC mains flex.
After many, many gallons of airtime with glow fuel the whole of the interior fuselage had a good bit of oily residue on it. I used the meths and baby wipes as best as I could, then a little talc and lots of kitchen towel.
As far as I could ascertain the underlying structure was fine, which was a huge bonus. There were no glue breaks or plywood creaking when I squeezed the fuselage. Frankly, it was built like my grannie’s wardrobe!
I polished the pilot’s canopy with a bit of toothpaste, buffing back with a soft cloth. I stuck down any loose trim as best I could with a hot iron, but some would not stick, even with a solvent. I cut these off neatly.
On her first flight after the refurbishment, she flew superbly. And ground handling went from ‘theoretical’ to actual.
All in all, a super little weekend workshop project that saved the planet, as well as my bank account. You can’t beat a good refurb, so I commend it to you!
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