Rubber

[Littleboy]

PS, I am NOT awesome and being an injineer, fully appreciate spelling korrecshuns.[/quote]

Thanks for the help

(you misspelled engineer)

[blue cobra]

I'm using 0.090" rubber and with both the broad and narrow bladed Ikara props I land with a LOT of winds left. Like 40 on a 15:1 winder (600). My plane also seems to fly a bit fast. I tend to break thicker rubber, and I know most people use rubber about the same or even thinner than I do for similar props, so I'm confused as to what to do.

[jander14indoor]

More details needed. How high a site. Plane weight. Wing size. Describe a typical flight. Gym size. Turn radius. How high off the ground do you launch. How high do you go. How long does it take to climb to max height. How long is the cruise. How long a descent. How does your plane behave on half winds? What are your trim settings.

Note, in a low site, its hard not to land with a lot of turns, but that does seem a little high. Rule of thumb, you should land with the same amount of turns as your back off from max torque (just short of breaking) to launch torque.

Thanks,

Jeff Anderson
Livonia, MI

[blue cobra]

I'm terrible at estimating these things, but with some help and some new/thicker rubber I didn't land with quite as many winds (and finally broke two minutes!). It's not ideal yet, and with my completely unsupportive school I don't think I'll be able to get it ideal.

But my question today involves O-rings. I got a tube of what I assume is teflon to cut o-rings from, and they are terrible. They stay open, but they break after one or maybe two uses. I've cut them so thick that I can barely get it onto the prop hook, and it still gets sliced right through. I guess I'll have to use rubber ones.

Also, with my torque meter (based off of Ray Harlan's plans), it's very difficult to transfer my rubber to my plane. The 1/32 music wire used for the hook bends as I try to get my rubber off, and there's so much tension in the rubber that it often slides so that the o-ring is under my finger. The o-ring just barely fits into the opening on the prop hook anyway, and so this doesn't help. It also doesn't help that the prop, along with the prop hook, keeps spinning. Can anyone help with this?

[jander14indoor]

Sounds like the tubing you found is too small of a diameter, and too thin of a wall. My O-rings generally outlast my motors.

With a larger O-ring you'll have less of the other problems, but you still have to grab it right to keep it from slipping between your finger tips and making it hard to get onto the hook. I prevent this by pinching the motor right behind the hook with my fingernails almost touching between my thumb and index finger.

As to spinning prop, let me describe how I transfer the rubber to the plane, by myself.
First, I set things up conveniently.
Have the plane with in reach when the motor's wound. I like it to the left of the motor as I wind, you'll see why shortly.
I wind on a torque meter clamped to a table.
When I wind motors, the tail hook end and knot are at the torque meter, the prop end is at the winder.
For the next couple of comments, I'm right handed and this works for me. My right hand is doing all the finicky stuff, the left much easier items. You MAY want to reverse all this if you are left handed.
With motor wound, hold the winder in your left hand, pinch the motor behind the o-ring and remove it from the winder. Get rid of winder, put it in pocket, hand to assistant, drop it, whatever, but don't try to keep it in your hand for the rest.
Pick up the plane with your left hand holding it by pinching the front of the motor stick with you thumb and index finger, fingers on either side of a prop blade, preventing the prop from spinning. For the rest of this process, your left hands only job is to support the plane and prevent the prop from spinning.
Hook the motor on the prop hook with your right hand, be careful not to jam your tail into the table or the torque meter.
Pinch the motor with your right hand again behind the o-ring at the torque meter and remove from meter.
Hook motor onto rear hook.
Go fly plane.

If two people, same basic steps, but extra care needed not to break plane with two people moving around it.
Again, set things up conveniently.
One person's only job is to hold the plane and present it to the rubber handler. Don't try to touch the rubber to help, you won't.
The other person's only job is to handle the motor, wind it and put it on the hooks. Don't try to touch the plane, you'll break it. At most, touch the plane handler's hand to steady it to yours.
I like the plane handler on the left of the winder (I'm right handed again). Hold the plane by the front at the prop preventing it from spinning and the back by the tail hook. The motor stick should be level to floor, but wings turned up and down so the belly of the plane is presented to the winder. You have two jobs here. One, hold the plane steady and near to the motor once wound so the winder can transfer motor from winder and meter to plane, and two, DON'T jam the tail of the plane into the table.
While winding, stand away from the motor and winder until its ready for the plane.
Again, I wind motors off the plane on a torque meter clamped to a table. A simple stooge (hook) will do as well if you aren't using meters yet.
When I wind motors, the tail hook end and knot are at the torque meter, the prop end is at the winder.
Again, I'm right handed and this works for me. My right hand is doing all the finicky stuff, the left much easier items. You MAY want to reverse all this if you are left handed.
With motor wound, the plane holder approaches the winder.
The motor winder holds the winder in their left hand, pinch the motor behind the o-ring and remove it from the winder. Get rid of winder, put it in pocket, hand to assistant, drop it, whatever, but don't try to keep it in your hand for the rest.
Hook the motor on the prop hook with your right hand, DON'T grab the plane to steady it with your left hand, at most, steady the plane holder's hand.
Pinch the motor with your right hand again behind the o-ring at the torque meter and remove from meter.
Hook motor onto rear hook. Again, don't grab the plane with your free hand. At most steady the plane holder's hand.
One of you, go fly plane.

Hope that's clear, its easier to do than explain.

Jeff Anderson
Livonia, MI

[blue cobra]

Thanks. I was thinking that if winding clockwise the winder end must be the hook end, but now that I think about it, it doesn't matter which end is the hook end, it will spin the prop the same way. That sounds a bit easier than what I was doing.

But does pinching the rubber with your fingernail damage it? I'm afraid of getting nicks in the rubber.

[jander14indoor]

Depends, how sharp do you keep your nails?

Jeff

[mg]

Does rubber absorb amour all over time adding weight? I weighed some cut bans from last years competion that have been soaking in plastic bag with amour all and they 0.03-0.05 gm more than last year(even after drying off with paper towel). When making new bands for Nats should I shoot for 1.48 gm and weight to add amour all the last day before competition or is it ok to soak them over the up coming month. Thanks, mg

[YadoMestor]

Well normally, most people lube their bands immediately prior to flying. I'm talking like ... right before they wind their planes. There really is no need to soak the bands in Armor All over night. I'm not sure if it's bad for the bands, but from my point of view ... there's no substantial gain, other than weight gain.

[mg]

At my state competion the judge had me add lube prior to the weight in and said that I could not add lube after the plane and bands went through the official weigh in. Does anyone know if at Nats we can weigh dry bands then lube right before the test/official flight? I have all my cut bands soaking in individual sandwich lunch bags labeled with size, weight, and nuber of flights used. Its just easier to pull out a lubed band out of a bag, then to spray it before each flight. What then is the proper technique to add lube to the band ? Should I dry all the bands out to see if weight changes? Thanks, MG