Okay, so I’m selling YS …. But I just like them; kind of like riding a Harley, it’s the sound. Then there’s the fact that you are not governed by the eight-minute battery safe zone, you can fly longer each flight in prac- tice. Not that this will make you popular at the practice field during the Nats in Muncie! To be fair, electrics are easier on the airframe and electronics with much lower vibration. But to be equally fair, glow engines provide an extra power cushion for pilots that get in trouble. Power can solve many things! Every- body has to choose their powerplant; I’m just pointing out my reasons for flying YS. Getting started with a YS engine, you have to mount it in the airplane, and my pre- ferred mount is made by Merle Hyde. Chip’s Dad didn’t make the first soft mount, but he has manufactured the best for a long time. He also makes electric motor mounts. Merle told me that he made a few especially for Dave Lockhart. I prefer using his mount without a limiter, as this is quieter. The mount is designated as an AR85. This


is an 85 durometer rubber mount, with alu- minum beams that only hold with two screws at the back of the engine. It is more than enough bolt for the task, as long as you re- member to use the blue thread lock com- pound, not the red. The red is a bit too perma- nent, but the blue can be removed if necessary.


The Hyde mount is an ounce lighter than any other mount that I would even consider using. Another excellent mount is supplied by YS, as is my header of choice. The YS mount has a limiter that looks just like a small shock absorber, is made by Tamiya, and is a part that needs a fair amount of maintenance. I’ve flown a Hyde mount over 2000 flights without any maintenance what- soever. It never failed, although I did crash the plane on signal loss.


Stories are often told about planes that


have a thousand flights, but if you fly half the weekends in a year, eight flights per trip, both weekend days, that is only 416 flights. I keep flight logs and have docu- mented over 2000 flights on a Hyde mount. If you use the Hyde mount, be sure to make room for engine movement from side to side. The needle valve extension will need a healthy slot, or it will cut the cowl. Ditto for the header and valve cover, if they protrude any. Be generous.


Keeping the engine quiet is a big subject; most of the noise will come from three areas—the prop, the airframe and the car- buretor. Large diameter props are great with braking, and create a large area of dis- turbed air for control surfaces to operate in. But, big props turning at 8000 rpm will generate tip noise. Increase your pitch to drop the rpm and contain prop noise. 7100 rpm is a good target. A good stiff prop helps too, which is why most of us use the APC www.apcprop.com. I don’t know many still using wooden props; they flex too much. Of course, airframe noise is a big reason for using the soft mount. Don’t forget that airframe noise is a product of vibration, though. It must be addressed for best re- sults. Stiffer mounts and limiters contain the amount of engine movement, but at a price. You will need to observe and address vibration due to engine movement at idle, midrange and high speed.


It’s a shame to beat a dead horse, but back to props, the wrong prop can aggravate a vibration issue. When you are dealing


FLYING MODELS


with tight constraints, such as Pattern rules, when you fix one problem, you often cause another. Everything has to work to- gether in a successful Pattern airship. Finally, on the noise issue; there are two ways to deal with carburetor noise. First, you can use what is known as a velocity stack, which can be obtained through Cen- tral Hobbies www.centralhobbies.com. This is a small venturi intake which slips inside the air intake. It increases power as well as fuel economy. We won’t get all technical here, but it has to do with the velocity of the air moving through the unit. Alternatively, you can use an intake filter over the carbu- retor. Several are available, I’ve even seen panty hose material stretched over the in- take and wired in place. Needless to say, I’ve never done that myself; I’m just sayin’. Some people add foam inside the cowling to direct air flow over the engine, but I do not find it necessary. Just make sure you have more air outlet area than inlet area to the engine compartment. Call Richard Verano for the YS header, it is new and it is fantas- tic. This latest header screws directly into the engine without any flange bolts. Prior to this new unit, most people were using the Hatori header, which is a good unit as well. Also, when I’m calling Central Hobbies for the engine mount, I ask for a Hatori 821 pipe and a Nishioka tall mount.


The CDI needs an eight-ounce tank; glow needs sixteen ounces. (The CDI unit weighs four ounces in addition to having to use a slightly beefier battery so it’s a wash.) Any


tank will do, but I use the Tettra “Crank” tank. YS engines come with a special clunk to install in whatever tank you use. Glow plugs can be either OS “F” or YS plugs. Spark plugs come from YS. I go for simple and use the glow version, myself. The CDI version has a smoother idle, and uses less fuel with an almost nonexistent smoke trail. Still, the glow only version is a lot easier to operate, and is lighter at the end of the flight.


Choice of prop isn’t easy to tell; so much is determined by your particular plane, but a 19–11 or a 20.5–10 is a good place to start. If you need to change, you won’t know it un- less you fly one of the higher classes and by then you should know what to do. Hebert uses the APC as most of us do, but he adds tips to the ends in his shop. APC can pro- vide a 19.5–10.5 prop if asked, which is one that Bryan likes to modify. Another huge thing to remember is, use a flexible connection for the throttle. Hard pushrods will break; this engine moves about a bit. It’s not much fun flying for 25 minutes at a high idle until your fuel runs out to land, so take care with the pushrod to see it is able to move with the engine. For the future, YS has an engine being developed specifically for the high altitude in South Africa this year. Let’s see if it makes its way down to the rest of us! Either way, YS will continue to be relevant in Pat- tern for some time to come. If I can be of any assistance, please send an e-mail to wincons@aol.com.


39


This photo shows the latest YS exhaust header (above), which screws in with no bolts; the Hatori 821 pipe, the Nishioka tall pipe mount and the Hyde motor mount. The Hyde mount is an ounce lighter than a YS mount. Sixteen-ounce tank (below); notice the flexible throttle pushrod at the top. Read the text for its purpose.


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