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From the Tampa Bay Line Flyers Controline Model Airplane Club

Getting Started

by Ward Van Duzer

When we all (most of us) started back in the 1950s and 1960s, Control Line was simple. You flew controlline, or Control Line, or C/L. The venerable Fox .35 was the basic choice engine for Stunt. Then came the K&B Greenhead .35, followed by the O.S. Max S.35. What more could you want?

Then came RC. No, RC wasn’t bad, but the flying styles were significantly different. Slow flying, precision maneuvers were out. Boring holes in the sky were in. The engine manufacturers were sure to follow the needs/wants of their customers. And the 2/4 break was lost.

Engine technology today is so far advanced from those days it’s hard to imagine. Horsepower to cubic-inch ratio has nearly doubled. Unfortunately that comes at the price of rpm. We ran our Foxes at about 8,800 rpm on 10 x 6 propellers. Today’s engines are designed to be happy about 14,000 to 15,000 rpm. No longer can you get most engines to run at a 2/4 break and drive our airframes at a comfortable 55 mph.

These changes are based on metallurgy, and mostly, engine timing. The metallurgy is good news. No more iron pistons, and weak piston rings. But the timing, ah, that’s where our problem exists. Our modern engines want to run, by design, at 15,000 rpm. Set the needle to on the ground at 9,000 rpm, launch it, and … wahoo, 15,000 rpm. That is commonly called runaway; very frustrating for a Stunt pilot.

Frustration is something you should be leaving at work, not taking to the flying field. But it happens all the time. We’ve all seen it. Why does it happen?

There are folks out there using RC engines with carburetors wired open. Or, running engines that the manufacturers have claimed to be CL and believing that they really are. Sure, it has a Venturi in it, but the similarity ends there. Sad to say, but most manufacturers have no clue as to the size of the Venturi, or the timing that we require on our engines, to do our job. Now there are a couple of engines out there that either by accident, or intent, will work for us. But, even they can work better with some simple modifications.

Notwithstanding the fact that these engines were designed and timed to please RC enthusiasts whose sole purpose in life is to bore those holes in the sky. No folks, this just is not going to work for us.

Enter the engine guru. There are numbers of them out there. Their skills are in retuning these modern engines to work at our lower rpm, without giving up much of their horsepower. Now beware, almost anyone can detune an engine. The secret is to detune without giving away all that power. Secondly, your guru needs to be available when you need him if you’re having a problem with his product.

If you want to get the maximum pleasure, with minimum frustration from the CL stunt hobby, you’re going to have to run good, solid equipment that will be there tomorrow. Cheap equipment, built in countries that may not even exist tomorrow is not the key to success. Where will your parts and engineering help come from? We have already seen more engine manufacturers (and countries) disappear then we can count on both hands. You don’t need that to happen to you in the middle of your program.

So, what’s a body to do? Talk, ask questions, think! Check with fellow club members. Talk to the advanced and expert fliers in your group. See who they trust to do their rebuilding. There may be someone in your club who does engines. But, make sure all of his engines are winners. You don’t want one of his losers. If that source is not available to you, look to Stunt News advertisers. But, check them out too. Some only modify one brand, size, or kind of engine. Some have large epoxy bills. See just who builds what, and for whom. Remember, your money is just as green as that of a world champion. No, you probably don’t need the latest $300-$400 piped Blunder-Buss .72, but a couple of solid O.S. .40s, .46s or T.T. .36s will keep most of us happy for sometime thank you.

Think about your engine selection before you pick up the phone, but do discuss this with the rebuilder. Don’t even think about making a final selection until you know the weight of the engine. (There are plenty of really good anchors out there!) Is there a custom (light weight) muffler available for your choice? Are you basing your decision on a current fad engine, or will your choice be around for years? Are repair parts available? Will repair parts remain available? Don’t select some copycat clone because it’s $5 cheaper. Run the good stuff. You’ll use more than $5 worth of aspirin with the cheap stuff.

Now remember, these are custom-built engines. They are not just sitting on the shelf waiting for your phone call. And the better rebuilders do have a waiting list. Not to mention that some engines can go off the manufacturers shelves for month at a time. So do order as early as you can. Don’t wait till the end of the weekend before the contest, or you’ll be disappointed, or worse yet, you’ll be forced to use some rebuilder who is sitting around with nothing to do. While you’re at it—since there may be some wait time for your number to come up—why not order a second engine at the same time. If you are like me, or most other sport fliers, you do have (or will have) more than one airplane in your fleet. And there is much to be said for reliability, consistency, and understanding when running similar engines. And if you do have a problem on contest day, you now have the ability to swap out engines!

More good news with a custom-built stunt engine is that is can be built to run the way you want it to. Like the fast food folks say, “Have it your way.” Do you want a 2/4 break like a classic Fox .35? Tell your rebuilder. How about a high-speed stunt run—using low-pitched propellers—on a muffler? Want to try a tuned pipe? You’ll get what you want when you ask a talented engine guru. And, listen to what he tells you about running his engine.

You really do need some quality equipment designed for our purposes to enjoy your hobby to the max. One good solid O.S. or Thunder Tiger will cost you less than two afternoons chasing a little white ball around and, you’ll have that engine for years after you’ve lost that little white ball. For more information on engine rebuilds, proper fuels for your engine, and how to go about breaking in that new BelchFire .46, ask your clubbies. They are there to help you. Q

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