Goldfields Report ----- August 2000
G'day from the Goldfields.
Thanks to Peter for filling in for me last month. I've had a very hectic few weeks, with a trip to Perth for two weddings. My youngest sister's and my own, and also a house move across town. The new house is absolutely beautiful, but does not have a workshop yet so progress on the Caribou is at a standstill.
I must report, however, that my first pre-move attempts at fibreglassing have been disastrous. I made a number of mistakes. Mistake one was using a batch of poor quality epoxy to coat the plug that I had manufactured for the cowling from Polystyrene and Rapid Spak filler. The resultant poor finish meant that I had to come up with a way to fix the surface blemishes. I decided to use automotive filler over the whole plug and sand it back again. This took ages, but gave a fantastic surface finish. I then glued the plug onto a square of laminex and proceeded to wax it heavily.
Mistake two was believing that the wax is designed to act as a release agent. After coating the plug with a gel coat consisting of a mixture of Q cells and epoxy, and allowing it to set to almost firm, I proceeded to lay on the fibreglass cloth starting with 3/4 oz satin around the tighter curves and finishing with 3oz in a number of layers until I was happy with the thickness.
Once it had cured I attempted to remove the plug from the new mould. After trying for a while, I decided to destroy the plug to get it out. I dug it out, but had a layer of automotive "bog" left on the inside of the mould. My conclusion was that the bog had adsorbed all of the wax. I was able to carefully remove all of the bog over a period of a couple of hours. I then proceeded to wax the hell out of the mold to attempt my first cowling. I went ahead and mixed up a gel coat, applied it and then made mistake number three. The gel coat did not harden sufficiently until late at night, too late to start laying down the glass cloth, so I left it until early the next morning. As a result the gel coat did not bond properly to the following layers of cloth.
Once the cowling was complete and cured I attempted to remove it from the mold, and wasted a lot of hours and quite a few dollars worth of epoxy resin, glass cloth, automotive filler, spakfiller etc etc.
I did, however, gain a lot of valuable experience and hope that my next effort will be more successful.
The most important lessons were these 1) always use the best available materials 2) wax is only intended to fill very minor blemishes to plug and mold surfaces and its release qualities are minimal. It must be used in conjunction with PVA release agent. 3) Apply gel coats early in the day so that sufficient time is available to finish laying on the cloth. 4) My gel coats contained too many Q cells making them too thick and brittle. Consultation with Gary Adams and others has suggested that for my purpose, the gel coat only needs to be a thing layer of good quality epoxy resin without any Q cells, providing that a very light and high quality cloth follows the gel coat. 5) Careful examination of the fibreglass cowling supplied with Gary Adams' Kyosho Spitfire has also shown me that my finished article would have been twice its necessary thickness as the shape of the cowling provides a fair degree of it's strength, not it’s thickness.
Anyhow, for now the Caribou is on hold for a while, allowing me to concentrate more on the club's needs and activities. One the club front we have had a lot of action, mostly describable by the following :--- Mayhem and Carnage.
Peter did a good job on the last article, however he did have the effect of putting the scribes curse on Ray Harding. The glider Peter described went AWOL towards Kambalda never to be seen again and Ray also crashed his trainer on the same day damaging it, luckily not terminally.
The following weekend was even more fatal. Our most distant member, Brenwyn Mills crashed his ARF .25 low wing model after a brief lapse in concentration, totalling it. Peter de Groot totalled a brand new Viper combat model after thirty seconds of very erratic flight due to overly sensitive controls and I suspect some flexing of the ailerons. (you are too generous. The control surface throws were at least triple the spec and I can't fly - PdeG). This model was sent to Peter free of charge from the USA for use to appraise by an American manufacturer. It appeared to be a promising alternative to our current combat models, as it was constructed of Correx, a plastic board similar to cardboard in construction. You may have seen it used here for real estate signs and the such like. The fuselage was made out of 2 1/2" square PVC drain pipe. Certainly cheap and strong, however this particular size does not appear to be available in Australia, negating many viable alternatives to try out.
If anyone out there knows of a source of 2 1/2 square PVC downpipe or works for a PVC product manufacturer and would be prepared to assist with the tooling up to produce it, please contact me or Peter. Peter has the contact details of quite a few people interested in acquiring some, and I personally would be interested in a few myself.
Digressed a little there ;- back to the carnage, which unfortunately included Gary Adams whose Sig Somethin Extra decided to allow one wing to become all aileron by popping out a locating dowel. Fortunately Gary was able to throttle back and the impact did little damage other than a cracked up firewall region.
Mike Proud dumped his fun fly with minimal damage and then I decided to finish off the day's entertainment by exploring ground effect with my old Scanner, and yes the ground does have considerable effect at top speed in the inverted mode.
The day's downside events were countered by Mandurah visitor Brian Wilkins, who put on an impressive display of flying with his large models and his smaller hack. We look forward to another visit from Brian, hopefully with some colleagues in tow.
Possibly we will be able to provide another day as good as the one Brian experienced as the following weekend was very ordinary as most West Aussies probably experienced, extremely windy. As the day was meant to have been a combat fixture, John Bates and myself were unable to resist the urge and engage in a bout of open hostility. Unfortunately, the tight and prolonged aggression resulted in one of the most spectacular mid air collisions ever seen in Kalgoorlie.
It literally rained small bits of aircraft for some time. As an indication of the severity of our engine/engine impact, the only salvageable part of my total gremlin airframe was one aileron. John salvaged nothing but his engine and receiver and a couple of servos.
My engine and electronics, except for 2 stripped servo gears, survived intact, although bruised, and I immediately fitted the receiver a battery pack into my second Gremlin to check out my level of interchangeability and practicality.
After some trim adjustment the second Gremlin flew great. To illustrate the degree of wind strength on the day, Trevor Parnell had a lot of fun experimenting with the reverse gear in his Precedent fun fly.
Perhaps Sunday will be a better day. Whatever happens, you will here about it here.
Best Wishes
Tim Bailye 08 90913714 email timbailye@hotmail.com
Web Site : kalnet.com.au/gam
Couple of web sites with Correx planes