Propwash April 2019 web.pub

to the life of your engine. We run in water, so it is always ready to rust up your bearing races and balls. Common practice is to flush the inside of the engine with WD-40 with the plug removed. Pump that out and then add your favorite after run oil. What is an after run oil? Clarence Lee an engine man of the ages told me many years ago to mix up AFT type F 50% with Marvel air tool oil at 50%. I have NEVER had an engine rust up. There are several variations of after run oil. Just make sure you use something at the end of the day. Also squirt WD-40 through you cooling system. I have seen cooling heads fused to the head buttons from corrosion. WD will remove the water and keep the cooling head working at its best. Fuel Health: How do I know if my fuel is still good? As I stated earlier if sealed and properly stored fuel will last for many years. I recently ran some Cox ½A fuel that worked perfectly. If castor has gone bad the fuel will smell rancid. If the fuel is cloudy it is full of water. If your plastic bottle sits in the sun and gets drops all over the upper neck you have a cloud of moisture in your jug. Fastest way to reduce the potency of your fuel, set in on the ground, leave the top off and it will suck water out of the air and ground faster them you can imagine. Keep it sealed and out of direct sunlight to make it as potent as it can be for as long as possible. Water does NOT compress so when induced into your combustion chamber you have changed your combustion ratio and mixture. Your favorite go fast isn’t going to be very happy. So, I didn’t tell you what oil to run, what nitro percentage to use or what oil percentage to use, but I did explain why we do what we do. Read your plug; it will tell you a lot about how you are running your engine. Lean is NOT fast - it only hurts the engine. When you suck the element out of a plug it can ruin the piston and sleeve in a heartbeat. If you are lucky, it will only get the head button, if you have my luck you will get all three. Nitro is selling for over $40 a gallon, Klotz is $53 a gallon, Methanol is $5 a gallon. My point is that fuel costs more today than ever before. Take care of your fuel so you get the most fun out of that gallon as possible. PROPWASH 16 April 2019 Advice on Building an Inertial Dyno By Lohring Miller NAMBA Safety Chairman I get lots of questions about the inertial dyno Mike Bontoft and I used to test gasoline race engines. Below is a compilation of mine and other’s advice for both nitro and gasoline engine dynos. Lots of people have built dynos for small engines. Below are pictures of a few. We tested 11 cc nitro engines on our gas engine dyno. They all burned holes in the pistons from too much load. Nitro engines run much closer to the edge than industrial style engines. The first inertial dyno for model engines was designed and built by Marty Davis and Brian Callahan. John Ackerman machined the dyno parts. I found an article on it at https://web.archive.org/web/20030205134346/http: / /rcboat.com: 80/dyno.htm and https://web.archive.org/web/20030209190150/http: / /www.rcboat.com: 80/dynotech.htm . It has calculations and mentions that they used a 3.75 inch diameter by .75 inch thick flywheel for .45 cubic inch engines. See the picture on the following page. From this article and our experiences, I don't see why you would need either a clutch or flexible coupling between a small nitro engine and flywheel. After all, the small nitro engines run with a direct coupled flywheel in boats and cars. You could just custom make a flywheel to fit the engine shaft. Be sure it's accurate and balanced. Record its rpm and you're set. I don't think a one way clutch is needed either. You're not talking about a lot of torque like in the gasoline engines. If you go with a separate flywheel, a coupling to take up mild misalignment might be good. Our Lovejoy coupling held up well with a hard internal element. The ball and pin style coupling was used a long time ago for model boat shafts. You might still be able to get them direct from Octura. Some are available on eBay. See https://gallery.intlwaters.com/displayimage.php?album=369&pid=3483#top_display_media if you want to make one. (Some people found that the Octura couplers didn’t hold up.) I would use standard vibration absorbing nitro engine mounts for the engine like those from Speedmaster. See http://www.rossisales.com/MOTOR-MOUNTS.html An article on our dyno construction and operation is available from Model Engine Builder magazine. It’s in issue 15 for $6.00. Performance Trends has more general information at http://performancetrends.com/tdkmotorsports/index.html . We tested engines from the Fugi 27 (pictured) at 2 hp to a CMB 35 with almost 12 hp. Normal tests ran from 12,000 rpm to between 18 and 19,000 rpm, but we sometimes ran to 25,000 rpm. We used a square key into Aeromarine collets for a 1/4" cable between our gasoline