|
Twisted Stick April 2007 Newsletter
Well guys, It's the first time I've ever been a month late with the newsletter. I'll try not to let it happen again. I'm just undergoing a bunch o stuff in my personal life. Nuff said. What I want to talk about is pre flighting your airplane(s) for the new season. Many of you are old hands and a have your own system or thoughts on how to accomplish this but for the new members I thought I'd tell what I do. You want to check all your linkages to flying surfaces. If you are using plastic clevis open them up and look at the pin. Use a magnifying glass if your eyes are old like mine. What you are looking for is wear. Anything suspect - replace it. Now if you are flying an ARF a 2 mm clevis is awful close to a 2-56 but a 2-56 will slip. Dubro sells 2 mm clevis or replace the whole thing to make sure everything matches. It's cheap insurance. Check the servo screws and the servo arm center screw for tightness. Check for slop. Pull gently on the hinges and check to see if any of the CA hinges are broke, it happens. If you pickled your motor like you should have in the fall, it should be good to go. Take out the glow plug and hit the motor with your electric starter to clear out the excess oil. If you did not pickle your motor I'd put some after run oil in it - this is especially true for a four stroke. Take off the valve covers and use some oil on the push rods while turning the prop. While the cover is off check the valve clearance. What you are trying to accomplish is to oil the camshaft so it doesn't run dry. I use Dextron Transmission fluid for my after run oil. It's cheap and works. Its use was recommended on RCU by Bill Robison who had more experience in motors than I'll ever have. Put some oil on the wheel bushings and check to see if your wheels track true. Charge your transmitter and receiver packs. It's best to charge them at .1C or 60 mA for a standard 600 mAH pack. C stands for the printed mAH rating on the battery pack. Standard packs can be charged for 14 to 16 hours with the charger that came with your transmitter. The reason to use the low .1C charge is to help equalize the cells. After you have equalized the cells you can quick charge the pack. If you quick charge without equalizing the pack you run the chance of the charger missing the peak and overcharging the pack or worse reverse charging a single cell in the pack. Your choice. Next do a discharge test. If you've purchased a charger like a Triton discharge at .5C to a level of .9 volts per cell. The mAH result should be within 20% of the printed battery capacity or replace the pack. If you don't have a battery tester, put the plane together. Put some paper towel in the exhaust to keep the oil off the carpet J Better yet set it on some newspapers and fly it in your living room while you watch TV. It should last at least 40 minutes before the controls become sluggish. Look at your transmitter level also, after 40 minutes it should still be in the green.
Gentleman,
Man am I going to get ragged on. I work with numbers for a living and I can't do as simple conversion of a fraction. Actually the brain just misfired and it was a simple transposition. :) You guys will cut me some slack right? :) For a discharge rate I wrote .5C. This is incorrect. I usually write this as C/5 but figured it would be easier to understand as multiplication instead of division. 1/5 is .2 So the typical discharge rate is .2C until the cell voltage is .9 volts. This will give you very close to what most manufactures use to rate the capacity of their cells. If you want to be more specific you'll have to use their discharge rates. You can usually find these on the Internet. A typical example for a 600 mAH pack would be to discharge it at 600 * .2 or 120 mA until for a 4 cell pack the voltage reaches .9 * 4 or 3.6 volts. Later, John If buying a simple battery tester is easier than
fighting with the wife look at the Peak Super Test by
Sirius Electronics for $70.00 |