Quickfire (oz15896)

About this Plan

Quickfire. Radio control sport model. Tractor prop layout. Wingspan 37 in, for .20 .32 engines.

Note the Flashfire (oz15895) and Quickfire both appeared in the same article in RCMW, July 1997.

Quote: "Finishing: I strongly recommend covering the fuz (and canard top surface FF) with 50gsm (1.5-2oz) fibreglass cloth and Epoxy resin applied with a phonecard scraper! It is very easy to do, gives a good increase in strength and adds very little weight. If you allow 2 days for the glass to harden it sands down nicely with 80/120/180 oxide paper ready for a neutralising blow over with car undercoat. Two coats of colour and one of lacquer finish the job perfectly. Horizontal surfaces are best covered with film and trimmed to taste. As an aid to hand launchinjg a good idea is to glue a strip of Emery paper about 2" x 3/8" on each side of the fuz., under the wing hinge line on FF and on each side of the rear hatch on QF.

Now is the time to fit the engine, canopy, tail-pipes, fin fence and all control surfaces.

Fit all the servos (using heli-type ball-joints where possible for minimum slop) then have a trial balance, trying the Nicad in various positions, to achieve the specified initial CG. When satisfied, install the rest of the radio in the remaining space and tidy up the wires. Last operation is one oft forgot - lateral balancing! With the engine at BDC hold the spinner in one hand and the rudder lower fairing in the other, see which wing drops first then add weight to the opposite wing tip until this is corrected; prototypes required 6-8gms. Find a brass screw of this weight and glue into the appropriate wing tip.

Test Flying QUICKFIRE: Due to the unconventional layout, the first flight was approached with a certain amount of trepidation (terror). The CG determined by calculation, was set at the front edge of the top hatch. Luckily the weather was perfect, 8/8 blue with a gentle breeze. It was a good launch, so no control inputs were needed for a couple of seconds, with just a nice steady climb away. Just the slightest touch of aileron to correct a tendency to bank (who forgot the lateral balance!) now let's feed in a bit more up - whoopee! one 2 second loop later it dawned on me that the pitch was a little too sensitive - in fact, very close to neutral stability. One very erratic circuit and landing later, a temporary 20gms strip of lead was added to the engine mount. Off we go again, totally different, square corners yes, but hands off flyability. Great fun! Reposition the Nicad, remove the lead and cut down all the rates. Add some negative exponential and lean out the engine a touch..! Yes, it's very fast, but then again, it'll go amazingly slowly as well. Enjoy..."

Quickfire from R/C Model World, July 1997.

Direct submission to Outerzone.

Supplementary file notes

Article pages, thanks to RFJ.

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