Before the photos here is a quick reminder of the BMFA competition classes and their different rules. Please skip these paragraphs if you have read them before!
The Open Rubber and CO2 / Electric classes have a total based on flight score plus static score, split 50/50. Four flights can be made and the score from the best flight counts. Static judging is very rigorous, and comprehensive documentation is required from the entrants. To qualify, you have to make a flight of only 15 seconds. This does not sound much, until you actually try it! The flights are judged on realism in the various stages of the flight, i.e. take off, climb out, cruise, approach and landing. No extra points are given for longer flights than 15 seconds. Thus a very detailed, heavy model can score lots on the static points, and should be capable of a 15 second qualifying flight. Of course, a heavy model will fly faster (too fast for scale speed usually), be harder to trim and probably do less well on the flight score than a lighter model (they also hit the wall harder!) As always, it is a fine balancing act between weight and detail.
The Peanut (13" wing span) and Pistachio (8" span) classes have different rules, in that the flying scores do depend on flight time. Realism in flight is not judged, just the time it stays up. You get a ten second bonus if you ROG (Rise Off Ground). Nine timed flights can be made and the best two are added together to give you a flight score (in seconds). This was a new rule this year - it used to be just 4 flights, and the general view amongst competitors was that this was an improvement. You could get some flights "in the bank", then spend time playing to improve things further.
The models are ranked in order of flight performance, and also in order of static judging. Bonus points are given in the latter for such features as multiple wings, scale rib spacing, having a pilot, separate control surfaces, exposed engine detail etc. The final positions are obtained by adding the flight position to the static position - lowest score wins. For example 2nd in static and 3rd in flight would give you a total of 5 points.
This year was the first appearance at the Nationals of my Curtiss F9C Sparrowhawk. The picture below shows it the day before, after I had added some extra details and a scale propeller (about time too!)
After failing to make 15 seconds in the first two rounds, I was relieved to qualify in the third round after opening the turn out a little, and putting slightly thicker rubber in (2 loops of 0.120" rubber instead of 0.115"). It stalled gently in the cruise, so for the final flight I added a small lump of Blu-Tac to the nose. This did the trick, and the last flight was a nice steady one, just let down a bit by a rather steep approach to the landing.
To say that I was surprised and delighted to discover afterwards that I had won the Open Rubber class would be something of an understatement.
My peanut scale entry this year was a new D.H.83 Fox Moth - something of a long running saga, as regular visitors to the site can confirm. As is traditional, the finishing touches were added to the model at 11.30 pm the day before the competition. Here is what it looked like on Saturday evening, minus the tailwheel, which was added later that night.
Trimming was carried out during the competition sessions, and fortunately it proved nice and stable, and relatively simple to get flying. I found it needed a large rudder offest to get it going in left hand circuits - something David Prior has also found with his peanut Hornet Moth. When we compared setups, they were very similar, including offest ailerons to keep the inside wing up in the turn. Hinged control surfaces are very useful trimming aids, as well as getting bonus points from the scale judges.
There is still much scope for playing with motor length and size to get the best duration, but I was happy with a best of 31 seconds ROG for the first time out. A decent static score helped the model finish 5th in class. Only sad thing was that I blew a motor winding for round nine, and made rather a mess of one side of the rear fuselage. Oh well, serves me right for not using a blast tube......
Undoubted star of the show, and deserved winner of the CO2/electric class was Peter Smart's amazing Messershmitt Me 323 "Gigant". The model spans 48 inches and is powered by 6 geared pager motors and Li-Poly batteries. Construction is conventional balsa and tissue, with a fine airbrushed finish. The real "wow" factor, however, comes from the clever electronic timer.
Picture the scene. The model is placed on the floor, Pete triggers the sequence, replaces the nose doors, and walks away from the model. After about 10 seconds the motors all start, and the plane heads off along the floor and takes off. After about 15 seconds the engines are throttled back, and the plane comes in to land. It was a truly impressive sight, especially the last two flights, when the turn was opened out a bit, allowing the model to land squarely on its (many) wheels.
I have no idea what is going on in there, but it looks very clever.
A truly majestic sight - the Me 323 cruises past on its six motors.
At the other end of the scale, here is Richard Crossley's delightful Pistachio scale Polikarpov I-16, with a wing span of just 8". I believe it is actually the same scale as Pete's Gigant, which shows just what a monster aircraft that was. I was amazed at how well the little Rata flew - it cruised around up near the roof structure as stable as you like. Best time was over 50 seconds. The model was of foam construction and weighed a mere 2 grams. Beautiful finish as usual from Richard, and a worthy class winner.
Mike Hadland had a brand new peanut scale Bucker Jungmann finished for the event, which as well as looking marvellous, also flew beautifully. From an ROG it climbed up to just under the roof struts, where it circled slowly for what seemed like an age, before gently descending. Absolutely perfect trim for this class. With a best flight over 5O seconds and a high static mark, Mike chalked up yet another first place in the peanut class.
Phil Siddall had a new pioneer model entered in the open rubber class - this early Avro Triplane. A challenging subject with excellent workmanship in evidence. Unfortunately Phil did not manage to persuade it to take off, but hopefully he will persist with it, because I would love to see this beauty floating round a sports hall.
Barry Pursglove used a computer printer to do all the corrugations on his Peanut scale Tupolev ANT-2. Looked very effective I thought. Imagine trying to draw them all on by hand!!
Don't think I have seen one of these modelled before - a Davis DA-2A entered in Peanut by Mike Harvard.
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