Baby Skyray modelStart Flying & Building
Control Line Model Airplane

1/2a Kits

1/2a size models are the easiest size to start with, because they are small, easy to build and the least expensive (generally about $50 to $60 for kit, engine and accessories). The 1/2a (half-a) class means that the engine's displacement is typically from .049 to .051 cubic inches.

Start with the right power plant.   The Cox "Black Widow" is the simplest engine to work with for the beginners because of its "ease of starting" , minimum break-in time and simple to mount because of its integrated tank design. The integrated tank radial mount design makes it very easy to install on most models. You don't have to deal with external tank and complicated plumbing involved with most engines.

Your first airplane, should be a "Trainer".  These are usually simple to build because the wing is usually a solid 1/8" plank of solid balsa wood as opposed to framing ribs and covering with silkspan and dope..  However, these models do not stunt as well as a ones with a built-up wing.

A good example of a 1/2A size trainer is the Carl Goldberg's Lil' Wizard which is probably the easiest to fly and build.   It also makes a good beginning mouse racer.

Cary Taylor hold Lil Hacker model


Stay with the solid wing, like the Sig 1/2a Skyray or Deweybird are good first saunter because of their larger planked wing-area. They are more crash resistant over grass and fly well enough to for you to learn basic stunts, like your first loop, inverted and lazy eights. Another good beginning stunt model is the Stuntman 23 by Carl Goldberg. I built several of these models as a kid. This model can do the AMA beginner pattern, if powered with the right engine. Also, Brodak's Basic Trainer is a bargain at less than $15.

Stuntman 23 model

 Our club has has a lot of success with the Li'l Hacker combat trainer from The Core House. The kit is made from foam core and light plywood and requires minimal time to put together and is cheap. You can get 2 model airplanes for less than $30. The flight performance is superb with a Norvel .049 or .061.

If you want something a little more advanced, the Brodak Baby Flight Streak or Baby Clown are  good built-up wing sport stunters that are very capable of doing the complete AMA pattern. . For serious 1/2A stunt, get the 1/2A Pathfinder from Brodak, or the Pinto or Stork from RSM


For over 4 decades, Cox 1/2A engines have been the choice for most beginners. These engines require very little break in time and are very easy to start and operate. I still think that the Cox Golden Bee and Black Widows are the 2 best engines for the very young beginner. The only problem is that the Golden Bee is no longer made and the current Black Widows are not very good for stunt flying because of the change in the tank vent design. Modification would have to be done to make then stunt worthy. Also the price of the engine is high and the quality of the current production engines has gone down.

So, this leads us to the question, "why buy Cox?" Our club has been very successful using the new Norvel 1/2A engines. Price and performance of these engine is superb, such as the Norvel's BigMig Startup .049 or .061. For around $30, the BigMig Startup series include, spring starter, muffler with pressure tap and integrated tank. Engine will easily turn a 5 X 3 propeller over 20K rpm. For even more power there is the AME series which can be used for control line racing or combat. However to achieve optimum performance, a bladder or pressure fuel system is required.

If you decide to use a Norvel BigMig Startup as a replacement for the Cox, I recommend that you shorten the nose of any stock kit by about 5/8". This is because the Startup version with its integrated tank comes out longer and heavier than the Cox Black Widow engine.

I also found that the stock pressure setup on the current Norvel BigMig Startup engines, does not work as well as a uniflow setup. Remove the pressure tubing off the muffler and replace the stock vent on the tank with a 1/8" copper uniflow vent. This will give your Norvel a much more even run from beginning to end and also extend the run. If you use an external tank setup, I recommend Brodak's BH-521 1oz. small wedge tank.


The choice for the proper propeller is one of the most important factors in control line flying because it determines the speed of your model. 1/2A size propellers for most applications range from from 4 to 6 inches in diameter and 2 to 4 in pitch. For Cox engine, a 6 X 3 propeller has been the defacto standard, although I think this size is the upper limit of what a Cox engine can turn. RPM (Rotations Per Minute) should be about 14,000 to 16,000 for most cox reed valve engines.

For Norvel engines, I like to use a 6 x 2 or 5.5 x 2.5 pitch propeller because of the higher RPM (18K to 22K) that this engine can produce. However, if need the speed for combat or racing events, higher pitch is the way to go. The maximum would be about 4 pitch for these type of events. Remember, when you increase the pitch you must decrease the diameter to maintain the same RPM.


Use fuel with at least 15% nitro-methane for 1/2A engines. For Cox engines, use fuel that contains castor oil, because this will help lubricate the balljoint on the Cox piston and rod. For most 1/2A engines, total oil content should be at least 18-20%. Don't go too over board on the total oil because it can degrades the performance of these little engines. I found that the Norvel engines are much more forgiving when it come the amount of lubricant in the fuel. From experience, it seems to run better with a higher synthetic oil content. I use 18% nitro and about 1:4 ratio of castor to synthetic in my Norvel. I have see some people run fine on 18% synthetic lubricant that is common in regular R/C fuel, but I prefer that you spike it with some castor.

Lines and Handle

Please use a proper 1/2A handle for 1/2A flying. I see too many beginners use a control handle for larger models to fly a 1/2A model. For one thing the line spacing too wide and the leadout wires is too heavy which hinders your control response.

I like to use the SIG 1/2A Control Handle ($3.00) with a line spacing no more than 2-1/4” — that would be the 2 hole from the top. . If you are a beginner, use dacron line from about 35 feet radius. Don't go too long with dacron lines, because of the drag factor. As you progress beyond the first flight stage, you may want something that will give you less drag and more control. Start with .012 steel cable at 35 to 40 feet.

For serious 1/2A aerobatics, use .008 cable. On my Norvel .049 setup, I use .008 X 42” to 48”. The .008 cable is very fragile and requires extra care to prevent them from kinking. I like to modify the handle to accept steel line by adding adjustable leadouts which can be made from .015 or .018 cable. AMA rules require a safety thong around the wrist of your flying hand. Use a piece of leather or shoe lace. This is also a good way to distinguish between your Up and Down position. I don't know how many times beginners and even experts flyers have picked up the handle backwards with disastrous results.

Tools for Building

  • Titebond or Elmer's Yellow Wood Glue
  • Medium CA Glue
  • Xacto Knife No. 1 or Hobby Knife
  • Zona or Xacto razor saw
  • Sand Paper - 150, 220 and 400
  • Ruler and Triangle
  • Pliers with wire cutter
  • Screw Driver Set
  • T-pins
  • Quick Clamps
  • Electric or Cordless Drill


You can use 3 or 4 alkaline D cells, wired in parallel (positive to positive) for a starter battery. Get 2 brass or copper strips of metal from your local hardware store and connect them to the batter with some electrical tape or duct tape. Now you have a low cost starter battery that will last you several months.

If you can afford it, the Dubro Kwik-Klip ($20) is one of the most popular nicad rechargeable glow starter system for both Control Line and R/C application. The rechargeable battery can be replaced easily. This can be use only on newer Norvel's and any large engine. If you what to use this for a Cox head, you need to buy an adapter.

The third alternative is the buy a 1.5 volt hobby battery. They will last much longer than a nicad battery, but you can not charge them once they run down.

Field Box

Additional accessories you may need may include, battery clip, engine head wrench and extra glow plugs. You also need an easy method of fueling your engine. I highly reccommend a fuel syringe over other methods for fueling. Electric or hand-crank fuel pumps are just too wasteful especially on small engines. The fuel bulb use to be the most popular, but they are hard to find and the rubber can easily degrades especially with the higher nitro that 1/2 A engine require. Rubber particle can contaminate the fuel and prematurely burn out your glow plugs.

A tool caddy at $3.00 from most hardware store, can easily make an affordable flight box. To save weight, I bring only a 1 quart can to the field.


If you need to get started quickly and don't have the funds to purchase all of the necessary accessories I recommend, the "Cox Starter Kit" can get you up a flying.

Secrets for a Successful First Flight

Now is time to go to the field. Before you start flying, you must "Break-In" your engine according to the engine manufacturer's direction. Also, please follow all of the AMA safety guideline for control line flying.

The first steps to insure a successful first flight is to neutralize the models control to your natural hand position. I know that a lot of instructors recommend and very very narrow line spacing for the first timers to limit the beginners control I don't always agree with this because limitting also slows down the flyers reaction to get out of trouble. Rather, try to control the handle from different fulcrum points, such as arm, elbow and wrist.

First time flyer should only use the arm or elbow to control the model, NOT THE WRIST. Another fault I see with most first time flyer is the tendency to YANK the model inward because they feel a lack of tension in the line. However, the opposite is true because this makes the model slide-slip causes the model to dip. The third fault is WHIPPING. This is an advance feature on control-line flying, but you should not try to do this on your first flight. Don't pull ahead of the model with your hand, just stay with the model and let the engine do all of the work. Actually try the opposite, let the model try to pull you, instead of you pulling the model.

On your first flight, trying to stay up about 20 feet. Don't go too high. If you are too high on one side of the circle, it always result in becoming too low on the other side. Remember, there is a tendency for the model for rise up into the wind, so try to low your arm before the model reaches this point. The secret to flying level is just to be relaxed not stiff. If you get dizzy, try not to look directly at the model, by using you peripheral vision.

And most important, have lots of fun!

The Next Step - "Bigger is Better"