If you aren't breaking motors somewhat regularly (maybe every 10 flights for practice, less for competition motors) you are flying a duration event with a partial tank of gas. Worse, you launch at such a low torque you don't have enough power to climb. That's what I saw in that video.
A handicap right from the start even if everything else is trimmed properly and you are at minimum weight.
Rubber isn't very pricey, FAI Tans Super Sport (from FAI Model Supply, the source for Dave's rubber and all true competition rubber) 1/4 lb is $10 plus shipping and will make you 70 motors or so. 1/2 lb is only $15, 140 motors! Since the FFM kit comes with 0.065, buy the 1/16 (0.0625 inch or so, close enough to 0.065in) and you won't need to worry about stripping it.
Once you have enough rubber, practice winding. Look at viewtopic.php?f=245&t=10094&p=305649&hi ... ue#p305649 you should find an experiment I recommend all teams make if you have a torque meter. It will teach you how hard you can wind a motor and how it behaves during winding and unwinding. It will teach you why you always wind past your target launch winds (or much better launch torque) and then unwind to the target.
If a torque meter is a new concept, search back through these strings for discussion on why winding to torque is far better than winding to turns. I searched on "torque meter" in the 2016 archive and found a bunch of relevant hits. I know there is discussion in other years too.
Expansion on why practice motors last longer than competition ones.
- During practice your goal is to understand the factors that make your plane fly well and long. For the most part you can do that without winding motors much past 85% or so of breaking torque and the motors last longer. You should do SOME practice on fully competition wound motors to make sure no surprised occur, but you don't need to every flight.
- During competition, you should wind the motor JUST short of breaking. 95 to 98% of breaking torque. And then back off to launch torque. Wound that hard, your motors just don't last as long. They start showing signs of stress and damage if you examine them closely and they break at lower torque than before the hard wind.
Sorry, please follow the FF instruction. I replied mostly from memory and not remembering the exact instruction and may have gotten it mixed up with previous model from years past.Maddie J wrote: We worked on the CG to be 1/2 in to 3/8 in in front of the Rear Wing Post--this was based on the instructions provided. So, it's confusing for you to say the Wing Leading Edge....
So, we should increase the wing incidence & if we get to where it is stalling, to lower it? We'll try raising the angle to get a good lift.
I see a trend on the winding--we're so afraid of breaking it. We'll reread the winding technique & see if that too helps. Thank you!
On the incidence angle, you don't want maximum angle before it starts to stall. This is something you have to play with to get the best flight time. Higher incidence angle means higher friction and less efficient glide which will cause you flight time. Too low and you don't get enough lift. You want enough angle to get enough lift for the ceiling height you will compete in based on the biggest number of winds you can do for the particular rubber size. These are all variables that you try to tune to get the longest flight.
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I used to use 3 in 1 silicone lube and it lead to a lot of rubber breaking, so I switched to armor all (the regular kind that you spray) and now my rubber doesn't break. This was the only video I could find on winding: https://www.youtube.com/watch?v=MrlH4WjYDGY Notice how much they stretch the rubber.SPP SciO wrote:Can you elaborate on the concept of "hard winding" - I feel as though this is the barrier to entry that's preventing my students from success. We ordered Freedom Flight kits earlier in the season, and the students have also build a few planes from scratch. The construction, while far from perfect, looks decent, and the weight is always less than 8 grams. However, during the limited time we have to actually fly the planes, they're not getting them to climb.jander14indoor wrote:The turn looked right, no stalling in that short flight. That airplane is capable of MUCH longer flights, easily reaching the ceiling. It might need a few trim tweaks, but it is capable.
Assuming you are at minimum weight, you just don't have enough power. Even if you aren't at minimum weight, you need even MORE power.
How do yo get that, you need to wind HARDER. A 0.065 motor that length should have well north of 1250 turns, probably well north of 1500. You may need a thicker motor too, but you'll still need to wind it HARD.
Now, you may find trim issues as you wind harder, so you might want to go in steps. But I'd start with a big first step. 50% more turns, even 100%. You haven't begun to stress that motor yet.
Once it starts climbing with more power you'll probably find some trim issues, but right now you need to focus on winding harder.
They've read about the idea of hard winding before, but they seem to break an inordinate amount of motors. They've been using 3-in1 brand silicone lubrication, and the o-rings and rubber provided in the kit, measured to close to 1.5g, along with a 15:1 winder. Still - no lift, even if they manage to give it 100 winder turns. Of course, the plane touches down a few seconds later with nearly all winds still on it.
Personally, I know nothing about this event, and I've been very hands-off, letting the students experiment themselves. But, we've had 2 invitationals without success, and an awful lot of broken propellers. I really doubt the issue is the design, components or construction of the plane itself; I suspect it's competency of the flyers. I'd like to try building and flying my own over winter break to get a little experience I can pass on. Are there any recommended youtube videos which show proper motor winding / flying technique?
PURE silicone oil is fine, but a little tricky to find. Most common source I'm aware of is used for RC car shocks.
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