- This topic has 15 replies, 5 voices, and was last updated 13 years, 11 months ago by
.
-
Posts
-
For your consideration and comments, here is the way I would like to try Class A Electric Free Flight:
1. No restriction on size or weight of model.
2. Restrict controls to motor run time and D/T, any method available.
3. No restriction on the battery type or size, except the type must be readily available to the general modeling contestant.
4. Imput to the motor to be a maximum of 80 Watts.
5. 10 sec motor run and 2 min MAX.
desertflyer, Thanks for throwing out some ideas for Class A electric rules. Yeah, the need for change is long overdue. There were only 2 entries at the last Nats, so the event is just about dead as is.
I agree that there should be some limits put on Class A so that the event is clearly junior to Class B. I think the A models should be smaller, cheaper, and simpler than the unlimited Class B ships, but still have exciting performance. The limits could take the form of model size, model weight, battery weight, or, per your suggestion, input power. Whatever it is, the rules need to be simple to limit CD administrative burden.
Comments to your proposal:
Item 4. (input power) How would this be measured? Would power input need to be verified to CD’s via wattmeter test?
Item 5. (motor run and flight time) How many flights? Would flights continue indefinitely at 10 seconds and 2 min. max.? Is there a way to avoid marathon flyoffs?
riversIn my opinion putting the burden of measuring power on the CD is a good way to insure that Electric A will not show up on any contest fliers. How about if you replaced your wattage requirment with ” 7.4v or less”?
Well, I shouldn’t even be posting because I no longer fly competitively. But, based on my experiments, I felt the 80 watts imput power would pretty much limit the planes to 1/2A sized of 200 to 240 sq in.
I have a Fortastrop which is 212 sq in and ready to go weighs 6.9 oz. It has a BP A2204-19 motor, 360 mah Fusion Pack 3 cell, uses a Castle Creations 10 amp Phoenix ESC, a Z Tron Timer, a Blue Arrow 4.2 gram servo for D/T, and swings a GWS 7×3.5 DD prop at 11,000RPM and 80 watts input.
I haven’t flown it yet, but based on my Sundancer 330 at 11.6 oz and 100 watts power input, the Fortastrop should do better easily.
As far as flyoffs, I didn’t think that far. I go out and fly about 3 or 4 flights on one battery charge and consistently put up 2 minute maxes with a 10 sec motor run on the Sundancer 330. The only time I don’t is if I screw up and get some serious down air or launch it wrong. The Sundancer is a very forgiving plane so, it usually turns out ok.
I’ve never tried to use a 2 cell pack on the Fortastrop setup, but I have on the Sundancer. When I first tried it I was using a 2 cell 1320 mah battery and a GWS 2015 Brushless and a 7×5 APC E and it was marginal. I put a 3cell on and change to a BP A2208-12 and a 7×4.5 no name folder and had to completely re trim because of the better performance. I still haven’t had a good transition, and our windy weather is here now, so no new progress on that.
I just figured if you only limited one thing (wattage) that then anyone could do anything they wanted, even use a speed 400 brushed motor and 1500 Ni Cads, although I think everything would shake out to a small setup like I use in the Fortastrop.
How it would be policed, I don’t know. When ever I was a contest director, I figured if a guy wanted to win so bad that he would cheat, let him. Pretty poor human being in my opinion and he would have to live with it, not me.
desertflyer, I think you have astutely identified the kind model of that would attract new flyers to Class A and start a pattern of growth.
Your projected airplane is 1/2A size, say in the range of 210 to 240 sq. inches, easy to build from existing plans, and uses low cost electric components. A power system of approx. 80 watts is about right for the target model, and would result in very good performance.
However, I agree with Jim that input power is not the best way to impose limits. Very few electric flyers have the equipment or the motivation to measure amps,volts, watts and rpm. I think a better control is battery weight. This is similar to the the use of 10 grams of rubber weight in the P-30 and Coupe competition classes. Nobody has a problem with this. Based on your performance reports, and my own experience, I think a 40 gram max battery limit is about right (battery weight to include all connectors and wires integral to the pack). Therefore, I would like to take the liberty of modifying your proposed rule set as follows:
1. No restriction on size or weight of model.2. Restrict flight controls to motor run time and D/T, any method.
3. No restriction on the battery type or size, except the type must be readily available to the general modeling contestant.
4. Battery weight to be 40 grams max.
5. All flights to a 2 min max. First 3 at 15 second motor run, second 3 at 10 seconds, and a 6 second motor run thereafter until no max.
rivers-
I agree with your proposal. It makes a lot of sense. By limiting the weight of the battery, there are all kinds of possibilities for models and equipment that I hadn’t thought out. For instance, one might see a 176 sq in 1/2A Zeek with a Johnson 250 motor swinging a 4×2.5 GWS DD prop keeping right up with my Fortastrop. Guys, like me, that like to experiment and play, would have a ball trying to do something someone else isn’t.
I like it!
Regards,
Larry Lake
I like what I am hearing with two exceptions, one of the most popular batteries on the market comes in at 42g with connectors. Increase the battery weight to 45g. The second is the final motor run time of 6 sec. There are a lot of guys out there with timers that count down in 5 sec. increments. Make the final motor run 5 sec.
Dick, this hits on most of the issues that we have been discussing. I still believe that it is important that this model be legal to fly in both classes.Jim,
What is the battery that comes in at 42 grams? I would like to look up it’s power-producing potential.
The idea of the proposed 6 second motor run for the 7th flight and beyond is to give Class A a one second power advantage over Class B. I believe a small handicap is required to equalize the classes when they are flown together. Don’t worry about the setting of timers. I build electronic timers and know they can be made to do anything you want via reprogramming. Because of the lengthy rules change cycle we have nearly two years to get ready.
The battery is the Enerland 400mah 3 cell. The issue with the batteries and the timer is not the tech. it is the cost of retooling. There are a few guys out there using that battery and a timer that has a preprogramed timer.
Jim, I looked up the Enerland 400 mah 3S battery. There’s no problem tailoring the rules to admit this battery. Actually, the Enerland is not as good as the Fusion-Pack 360 mah 3S 25C pack used by desertflyer. His battery is lighter, cheaper, and has more power. My own 1/2 A electric model also uses a Fusion-Pack battery, but mine is a 600 mah 2S 25C pack. It’s about the same weight and cost as the 360 3S, but I have a high kv motor and a bigger prop to get the same power as desertflyer.
As you know, battery technology is constanty improving, so we never know what the next best hot cell will be.
I’m not ready to comment further on the 6 second motor run. I’m still in favor of it, but need info on the ZTRON timer, which is the lowest cost timer out there that has DT function. Again, we have nearly two years time to work out rules changes. Also, cross proposals are possible, so if anyone doesn’t like something they can submit an proposal ammendment.
I’m not an electric flyer and haven’t even seen one go here in Colorado yet. It seems to me what Electric FF power is missing is a class that is inspiring to present day gas flyers and wannabe’s. I guess that means something with hair on it’s chest that can stand up to a Gas equivalent. I know there is plenty of power available in today’s motor battery combinations so how about encouraging a class that could explore the outside edges of FF performance?
I would suggest something like a Pilfered Pearl 711 flying in an unlimited class until the ideas start to jell and THEN codify the rules. The only thing needed is a motor run (say 12-15 seconds) and possibly a maximum wing area rule. Get some high performance ships out there and lose the little P30 style putt-putts and you’ll draw interest.
Randy,
If you had attended the Dynasty Cup last September in Denver or the Southwest Regionals or some of the other contests where F1Q and electric B is flown,you might have a different view of what electric is capable of curremtly.
P.P.711 would be way too small for what’s possible even now.
F1J/ F1C performance is more like it.
Cheers!Electric B sounds like what I was referring to. I was indeed at the Dynasty Cup in Denver and don’t recall an electric there……but that wasn’t my point. I believe that electric has terrific performance potential and it needs to be demonstrated in order to draw participant converts from other free flight events.
- You must be logged in to reply to this topic.