Is armor all still viable? I read some amazon reviews and it seems they have changed their formula to make it more viscous.jander14indoor wrote:Sorry, not clear, 1200 is a single loop of 0.093 or so rubber. A double loop would never take that many turns and would overpower the plane if wound close to max. Just to make sure when I talk single loop that means there is one loop of rubber resulting in two individual strands running front to back. There is a way to have a single strand front to back, but not particularly useful for WS. Double loop means four strands front to back.
Hook length vs rubber length, just not important as long as you don't get TOO short. Loose hanging rubber is the norm for an unwound motor. Those first few wind (or last few unwind) turns will not provide any meaningful torque however you set the hook to hook length. And by few I mean 50 to 100 or so. Just use 12-14 inches hook to hook on these things and don't sweat it. I've flown some classes where the rules required about a 6-8 inch hook to hook for a 20 inch loop of rubber. Biggest problem with hanging rubber is it falling off or changing the CG unexpectedly.
Suggestion to understand torque vs turns, make up some short test motors and wind them with a torque meter taking data every few turns. Wind the first motor to breaking. Plot it. Wind the next identical motor to just short of breaking and then unwind continuing to take data. Plot it. You'll see why I'm saying the first turns are useless in powering the plane and why you MUST wind to near breaking. Reason and more details discussed previously, dig in the WS archives.
And yes you'll need some sort of lube to hit the turns you need to be competitive. But nothing hard to get.
- I use Armor All (or Son of a Gun) vinyl protectant, the original general purpose stuff, last time I looked there are a lot of specialized formulations. Works fine, I'm on my second bottle after 15 years. And the only reason I bought a new bottle was the old one was just NASTY smelling after 10 years in my flight box. One good spritz and that motor is good for many winds.
- Some folks use the silicone oil from RC car shocks. Also stays on.
- Haven't checked availability lately but there was a free flight supplier who sold a variety of amusingly named rubber lubes, things like Snake Snot, Mongoose Mucus, etc that was basically silicone oil.
- Old school was a mix of glycerin, soap and what not. Works, but not as good as silicone oil and must be reapplied.
- Whatever you do, DON'T use anything petroleum based, will ruin your motor like NOW.
Besides lubricant, you'll need to stretch wind to get those turns. Do some digging through the WS archives for more info on that.
Also, my plane doesn't climb as high as it should, and while it stays level, it kind of drops quickly. I'm using max sized surfaces for everything, and I'm barely over 8g. Should I change the cg, adjust lift, change rubber, or change the prop? (I'm using an ikarus flaring prop at the moment, 2.4g)
Is there a specific order in which you adjust things? i.e. if it dives, should I move cg back first or change the lift first? Likewise if it stalls, should I add downthrust, reduce lift, or move the cg forward? Is there a way to know which type of trimming is necessary?