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Mike Trautman

CCRCC Officer
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Mike Trautman last won the day on December 28 2017

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About Mike Trautman

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  1. CAUTION CAUTION! MAKING BATTERY PACKS CAUTION! CAUTION! I've been cycling batteries... per my own advice given earlier this year. The results have been equivocal at best and disappointing on several counts. My giant scale planes have large batteries. That should guarantee security, no? The Tigermoth has two 3000ma 6v NMH batteries, expensive, and often on back order. Well, the last “cycle” resulted in one accepting 3000ma and the other 179ma. That's not a good result. I'm still trying to sort out the settings on my two different charger that are supposed to cycle batteries automatically. Where's that darn manual? Meanwhile, I'm probably looking at replacing some batteries this year. I like large capacity 6v batteries. Often pricey and frequently back ordered. I am a ham radio guy. I know how to solder. I should be able to buy some rechargeable batteries cheap and make my own battery packs... right? Sure! Here's what I learned. I accept no responsibility for anyone else trying to make battery packs. Whether you burn down your house, or just crash a couple planes, It's not my fault. I'm not saying you should do anything the way I do. I'm just describing a few things that worked, and some things that didn't, in my hands, with my equipment, for my own use. Batteries: Tenergy Centura “Low Self Discharge” NiMH rechargeable batteries, 2000ma, Amazon, $32.99 for a 24 pack of “AA” size. Tenergy “Sub c” batteries are available for $5.45 each. I've seen other Sub c's available for less, but they carry a lot of of negative reviews for lower capacity or reliability. Stick with the good stuff! It's still much cheaper then ready made packs. For 4.8v you need four 1.2v batteries in series. For 6.0v you need five 1.2v batteries in series. If you don't understand the difference between batteries in series and parallel, stop now before you hurt yourself. Soldering: Connecting batteries commercially is usually done with a spot welder. The weld is strong and heat transference to the battery chemicals and structure are minimal. Prolonged, gradual application of heat should be avoided. Use a low melting temperature solder and a large soldering gun or iron so contact with the battery is brief. Test each solder joint vigorously. Connecting batteries can be done with wires or metal straps. Do not try to solder aluminum connectors. Special flux and solder are needed for aluminum and the technique is tricky. Copper, brass or plated ferrous metals can be used more reliably. Test before use! Appropriate flux (resin only please) is helpful. Cleanliness is next to godliness! Pre-Assembly: I strongly suggest assembling your battery pack ahead of time, using a strong adhesive. I have had failures with hot glue, not to mention the possibility of high operating temperatures affecting it. Your solder joints are not enough to hold your battery pack together without help. Epoxy, or “Shoe Goo” seem to work well. A linear arrangement can flex and break your solder joints more easily then a stacked “hump” arrangement. I go with a humped pack when I can. Design: Depending on your voltage requirements and the number of batteries you're using, you need to think about the path of the wiring and connectors. I like to start with one battery and add more, visualizing how the electricity will travel along the circuit through each one. A mistake here can be dangerous and costly. 6V doesn't seem like a lot, but I have suffered 3rd degree holes burned into my fingertips, just by momentarily placing a strap on the wrong two contacts. Place and hold your straps with a tool, not by hand. The brush/spark test can be useful too. Lightly touch (brush) the strap between the contacts. You should not get get any spark or heat. If you do, you have a short and that's bad, very bad. Test, test, test: Make sure you have a volt/ohm/continuity meter that you know how to use. Once you have made all your connections, you should have the expected voltage at your battery cable connectors. Go back and look for cold solder joints and loose connections before you wrap your pack in tape! I once spent a maddening hour trying to figure out how I could have the right voltage at the battery pack, good continuity from the battery connection to the power connector, and yet still no juice flowing. Turned out that... 1. My glue joint had failed, allowing a solder joint to flex. And 2. I had a cold solder joint with intermediate contact... times two!... The straight line pack had separated both end batteries due to flexing. That is why I always go with the “hump” design when I can. Do yourself a favor and provide some strain relief for your power cable to solder joint connections too. Cables and connections: Years ago I bought a good quality cable making kit from Hansen Hobbies at E-Fest. I've never regretted it and have enjoyed making my own custom length cables and connectors since then. Most receivers use a JR or Hitec style connector on 24 to 18 gauge wire. 22 gauge is the most popular and sufficient for most uses. For battery connectors I like BENTECHGO 18 Gauge Silicone, 150 strand copper wire. Amazon, $6.48 for 20' (10' red, 10' black) I have used 16 gauge by stripping it to 18 gauge, but the 18 gauge is really the largest practical size to use with the standard R/C servo connection. Seriously, if you need more amps than high conductivity silicone 18 gauge can provide, you need professional design and fabrication services. Wrap it up!: I wrap my finished packs in self bonding electrical tape for insulation and physical protection when I'm done. Have fun! Don't blow yourself up! Mike Trautman Here's some pics: "Low Self Discharge" Ternergy AA batteries: Hump versus Linear arranements Big, Ugly soldering iron, but quick! Failed glue joint, failed solder joint! Some finished packs wrapped in self bonding electrical tape. Always
  2. Mike Trautman

    Mike Trautman

    Lipo Battery discharger... 50 ohm resistor with voltage display.
  3. Mike Trautman

    Cold Weather Flying

    Weather for the Chili Breakfast this year is predicted to be -9 degrees, with a "high" of -1 degree! NW wind 9-14mph. Yikes! Don't forget a scarf or mask for your face. Maybe some Chapstick for dry lips.
  4. Mike Trautman

    Rescue Projects

    Hi Mike, Congratulations on the Astron 40. I've seen it fly and the coolness factor is impressive! I agree about the personal connection link to motivation. I bought a 2003 Proctor kit 1/4 scale Fokker D-VII from Tom Griffith, originally built by Fred Kouka. Between my own inept flying and some weak points in construction, it occupies prime space on my project bench most of the year. I'm gradually replacing rigging, struts, undercarriage and upgrading hardware throughout. The unusual V-twin four stoke engine is awkwardly inaccessible and the fuselage is a fragile spiderweb of wooden dowels that appears ready to explode on any significant impact. The newer Balsa USA kits with slab sides and simplified wing ribs are probably much more rugged and easy to work on. But when pilots walk up and admire the museum like construction details and comment on the four stroke twin's exhaust note, it is very gratifying. I feel more like I'm a custodian of a work of art then a toy flying hobbyist. I guess that keeps me from putting the plane on the shelf and building the NIBs I've got sitting around. I inherited a framed up and ready to cover J3 Cub from the fellow who introduced me to the hobby. It's sitting at our place in Sarasota waiting for me to complete. When it leaves the ground for the first time, I definitely feel that Bruce's spirit will be in the plane. Happy Landings, Mike Trautman
  5. Mike Trautman

    SUGRU - Moldable Glue

    Sugru - This is an interesting new “Moldable Glue”. Firm consistency, holds its shape pretty well. 30 minutes working time. Full set in 24 hours. Result is a hard rubber like part. I had a broken cowling mount on my giant scale P-47. There was enough structure left to establish the position of the part, but I needed to replace a portion of the part with complex curves and precise angulations. Cutting and fitting a wooden part would have been tedious and time consuming. The Sugru is the same light grey as the firewall. The new piece had an “L” shaped leg agains the firewall and replaces the missing piece. It's bonded to the bottom of the old support. It seems to be well bonded and strong enough. I know it's hard to believe I could make a construction mistake, but somehow while replacing the wing mounting bracket (it was a rough season) on my P-47, I misaligned the 1/4” nylon bolt holes. After I realigned the holes, the bolt heads did not fit flush. With a little (green this time) Sugru I was able to seat wooden collars flush with the bolt heads. Instant strain relief, for the bolts, (and the builder). I can see many other possible used for this material. Someone said you can buy it at Target. I bought mine from Amazon. Happy landings! Mike Trautman
  6. Mike Trautman

    Cold Weather Flying

    Cold weather flying: A sailing buddy of mine says, “There's no such thing as bad weather, just bad clothing.” I suppose he's right. If men can go to the poles in furs and snow shoes, I guess we ought to be able to fly our planes in most anything. Well, anyway, there are those of us who are game to fly in less than perfect conditions, generally meaning cold, windy, rainy, or all of the above.... I thought I would share some of my own experiences and preferences for surviving the Midwestern winter RC experience. First of all... It's cold out there! Let's talk about keeping warm. Your most fashionable Ski outfit might not be the best choice for standing around on a breezy sub zero day instead of working hard zooming down the slopes. You need warm clothes and maybe some calories from an outside source. Clothing... from the ground up. Heavy, well insulated boots and wool socks of course. I find that “Toasty Toes” chemical warming packs really work well with my trusty old work boots. Another comfy option are big “Mukluk” felt lined snow boots. Better to keep those tootsies warm then try to warm them up after they get cold. Especially if you're old with poor circulation like me. While we're at ground level, be alert for icing. You know how dangerous that is! You can't de-ice the whole pits and runway area, but you can buy some strap on cleats to keep you on your feet! Jeans don't cut it! In fact anything cotton doesn't cut it. Get out your Carharts, or anything warm and wind proof. Long johns can help, especially some of the new synthetic high tech stuff. You might want to establish whether you have adequate “access” for those necessary trips to the little blue room. Layers are handy for the torso. A windbreaking outer layer is vital. Down or synthetics insulate well. Wool is still great. Avoid cotton undershirts. A little bit of sweat and you'll be miserable the rest of the day. Stick with a good synthetic that wicks away moisture and warms back up when you need it. You need your hands to fly. I love my little transmitter bag. I think it cost me $12 from Hobbyking. I toss a couple of “Hot Hands” chemical warmers and life is good inside the bag. When they're not in the bag, my hands are in gloves. Chemical warmers in the palms help to keep the arthritic old claws flexible. I stock up on warmer bags at Farm and Fleet for pennies on the dollar each Spring when they're on clearance. They say if you keep your head warm, the rest of you will be OK too. Start with the ears. Good earmuffs, or furry flaps plus something around the neck is good. Again, staying warm is easier then warming up later! Don't forget the eyes. Cold air blowing on my eyes makes them water and shortens my flights. It's hard to land while crying, even if they're tears of joy. I use those “Solar Shields” that fit over my glasses and keep the wind off my eyes. Sometimes if the glare off the snow is bad, I'll use the Solar Sheilds over regular sunglasses (clip-ons in my case). With the proper clothes and preparation the whole world becomes a big white runway! Have fun out there. Stay warm and good luck starting your engines! PS those heat packs work well strapped to batteries too! Happy landings! Mike Trautman
  7. Mike Trautman

    Firewood Available at the Field

    Nick Schneider's crew has cut down the poplars south of the runway. Nick says this should be great wood for burning in the fireplace. The 3" to 4" pieces will be cut to 4' lengths and stacked by the access road. Some wood has already been cut but not stacked. Anyone is welcome to come take what they need. Thanks Nick!
  8. Mike Trautman

    Paint Matching

    Custom Paint Matching - As suggested by Bob Miller and others - Dust and Son, north Cunningham, Urbana. Matched colors I needed, mixed paint and put it in aerosol cans. $20 / large can. Great service! Sold me clear coat that should help with fuel proofing. Will test and report.
  9. Mike Trautman

    Paint Matching

    Thanks Bob. I'll see what they can do with three projects I'm working on. Imn looking at this month's Model Airplane News, page 29, at Mike Gatwood's Convair. It says he used Rust-Oleum Ultra Cover Satin Clear, over Behr Premium Plus paint. I'm wondering if the Ruts-Oleum Satin Clear would be a good overcoat for the custom paint mixed by Dust and Sons. Might give it a try if they think it will work.
  10. Mike Trautman

    Paint Matching

    I've heard people talking about a paint store in town that can match paint colors and put it in spray cans. Can anyone remind me where that is? Thanks, Mike Trautman
  11. Mike Trautman

    Electronic Ignitions

    Symptom: Erratic "twitching" of control surfaces, increasing with lower engine RPM. This problem persisted for half a season on my Hobbistar / Evolution 15cc gas plane. I had two severe crashes and multiple scary episodes. After replacing radios, servos, optical switches, moving components to various positions in the plane and generally changing out everything except the engine, I discovered that the three wire servo style connector between the ignition sensor on the engine and the CDI unit was just a little bit loose. I had shrink wrapped it, but I thought I detected just a little movement, possible even internal to the connector. I used metal fishing leader crimp tubes to connect the individual wires. Problem solved and the plane has been a reliable trainer ever since. Takeaway: A solid connection between the ignition sensor and the CDI module is critical. Symptom: Erratic "twitching" of control surfaces, increasing with higher engine RPM. My giant scale P 47 originally flew with a Fuji 42cc gas engine. It suffered major control surface twitching and full throw locking until I removed the optical kill switch and isolated all the electrical components I could. The spark plug lead on that engine is unshielded. Replacing the engine with a DEL 55cc engine (shielded plug lead) solved the problem. Takeaway: Unshielded plug leads can be problematic with nearby components, like optical switches. Questions: Are CDI / plug lead components critically matched to their respective engines? Could I have just swapped out another ignition system and solved the problem?
  12. Mike Trautman

    Electronic Ignitions

    I would like to start a discussion topic on electronic ignitions. I am relatively new to the subject, but have already experienced some issues and problems that I can share with the group. I hope others will chime in with their own, tips and hints too. 1. Symptom: Gradual loss of power and RPM over a five minute period with increased missing and finally quitting at any attempt to throttle above an idle. I've never given much thought to the ignition battery, basically assuming that it draws little current and that the voltage is not critical. But this was bench running a new engine with an old battery that hadn't been charged in a long time. After checking for fuel flow/blockage and throttle function, I decided the ignition battery might just be low. Sure enough, after connecting a fully charged battery, the engine "runs like new". The takeaway: Gradual loss of power may be a result of a low ignition battery. Ignition batteries deserve the same respect and care as flight batteries.
  13. Mike Trautman

    Preparing a LiPo battery for disposal

    Hi Tim, I use a safe and sophisticated option for battery discharge consisting of a heavy duty 50 ohm resistor and a voltage readout. It slowly discharges the battery and allows you to monitor progress and verify 0 volts. I would be willing to put it in the frequency shed for general usage. I hesitate because of the number of adapters needed to fit the variety of batteries out there and the possibility that they might get lost or disappear. If we could collect a number adapters and secure them somehow, this might be a good option. Mike Trautman
  14. Mike Trautman

    Fiberglass

    I'm duplicating a cowl for a Funtana 90 in fiberglass. I have documented the process with photos and descriptions in a "Word" document, and thought I would post it here. I haven't see a way to upload attachments/documents to the forum yet unless it's the "Insert Other Media" box. Is this possible? I probably missed something somewhere. Please educate me?
  15. Mike Trautman

    Pay Membership Dues Online

    Excellent addition to the site. I'll definitely use it next year!
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