Well said Kang & John.
The long motors mentioned by Kang are only necessary in Cat. 4 sites & both Tom's & my +10 Min. flights were with motors in the 17"-18" length range. For Cat.1 & 2 sites, where most of the local flying is done, shorter motors are in order. Also, motor sticks can be lighter because launch torques will be much lower, so it is easier to build to minimum weight.
Gary Hodson
-----Original Message-----
From: Yuan Kang Lee <ykleetx_at_gmail.com>
To: Indoor_Construction <Indoor_Construction_at_yahoogroups.com>
Sent: Mon, Feb 13, 2012 3:09 am
Subject: [Indoor_Construction] Re: A6 evolution?
Although the current A6 rules allow certain specifications not deemed to be for beginners, such as a tandem layout or VP, these allowances have nothing to do with the 10+ minute performances that we have seen. Neither of these items have been on previous 10+ minute models of Tom Sova and Gary Hodson. Just because Bill Gowen's A6 is a near-tandem doesn't mean that's why his model flies 10+ minutes.
What the "experts" have figured out in A6 is that to do monster times, you have to run a very long motor. Bill and Gary used motors more than 20" long, weighing around .9 to 1.0g. The 1.2g minimum weight and the 6" paddle propellers mean that a long motor near the model weight is needed for high times.
The experts have figured out how to manage a 20" motor on a 6" motorstick, with a prop that matches the motor. The long motor is tricky because of bunching at the prop and tail hooks. Its takes a lot of experimentation and experience to get it right.
Don't lament too much on the current A6 rules. They are what they are. They are not significantly different than the de facto rules that have been around for many years.
The EZB situation and A6 are totally different. EZB became too hard for most when models needed to weigh 0.5g or less to be competitive. The minimum weight "equalizer" was not instituted and hence the competitors became a small group. In my opinion, adding a minimum weight requirement to a class is the single best way to level the playing field. But, anyway, that didn't happen in EZB.
A6 has a ton of "equalizers" like 1.2g minimum weight, flat prop, 6" motor stick, crazy requirements on spar size, etc. But these "equalizers" have the unintended consequence that flying a super long motor is necessary. And right now, it seems only "experts" can figure out how to do this.
So, beginners, figure out how to run a 20", 0.9 to 1.0g motor (hint: use sleeves and have a lot of motor clearance), with the right prop. Then, you and your A6 will be on your way to monster times. Also build it to the minimum weight and make sure it has razor sharp trim.
-Kang
--- In Indoor_Construction_at_yahoogroups.com, "Bob Clemens" <rclemens2_at_...> wrote:
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> In a letter to Roger Schroeder some years ago, Clarence Mather described the origin and philosophy of the A6 model:
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> "The San Diego Orbiteers held their meetings in a small recreation center gym and decided to do some indoor flying after the business meetings. A couple of us had some indoor experience and most of the other members felt overwhelmed by indoor models and did not participate. I decided to create a model that used materials familiar to everyone and was small, simple to build, and sturdy enough to survive most of the banging around that would occur. No special indoor materials were allowed.
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> "Thus 1/16 square strips and 1/32 sheet were the minimum sizes to be used. The "A" part of the name is from the old Academy of Model Aeronautics Class A model of 30 square inch maximum wing area. The span was not limited so that some experimenting could be done. A high aspect ratio might be efficient but would weigh more because of the longer spars required. Similarly the tail boom length was not limited. AMA rules limit stab area to 50 per cent of the wing's or it must be counted as wing area. Perhaps it would have been better not to limit the area of the stab. Tandems might be fun to experiment with. The added weight of the large second wing might cancel out the added lift because the rear wing cannot produce as much lift as the front.
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> "The flat sheet prop blades made the prop easy to build. The prop shaft and tube sizes specified, produces an easily built, smooth working front end. The six inch motor stick and prop diameter produces a well proportioned model. The wire wing mounts are not required. I use them on the plan so that trimming a model could be done easily-- balance point position (center of gravity), incidence, and wash-in can be adjusted with no cutting or gluing.
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> "I built and tested a model before we announced the event. Then plans were included with our newsletter. Fudo Takagi and I agreed to provide rubber for anyone who wanted it and we came with several sizes. So, a modeler could have a model to fly with little effort and cost. And it can be carried in a small box. The event meets our goals very well and flies three or four minutes in a small gym. That is long enough to be rewarding."
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> Apparently not rewarding enough, as A6 has since been felled by the "Easy" B virus.
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> Bob Clemens
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> (Donning my hard har, awaiting the inevitable brickbats)
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Received on Mon Feb 13 2012 - 07:28:56 CET
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