Author: Jim Hiller
Edition: Model Aviation - 2009/12
Page Numbers: 124.125.126
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Radio Control Jets

Jim Hiller [[email protected]]

The right introductory jet for you

So you want to get into jets but don’t know which model is right for you? That’s a dilemma I get asked about a lot, and the answer varies with the person’s skills, experience, and prospective flying field. Not all jet designs are created equal.

For all of you who ask which is the right first scale jet: how would you answer someone who asked you which warbird is right for a first low-wing model? Scale jets are not designed to be or intended to be introductory models. Some people have been successful starting with scale jets, but their skills, experience, and runway had to be optimal.

A variety of jets are available for beginners, and each is better at some things than others. One of my favorites is the Bruce Tharpe Engineering (BTE) Reaction 54.

This large balsa model is usually powered by a 14- to 20-pound-thrust 54mm turbine. The Reaction does many things well, mostly because of its large wing, thick symmetrical airfoil, and generally good design.

The PST Reaction 54 is the prepainted composite ARF version of the jet. It is a bit heavier and best powered by a 20- to 30-pound-thrust turbine.

The original Reaction is excellent for flying from grass fields. Its light wing loading makes for slower takeoff and landing speeds and shorter distances on the ground, and the landing gear mounts are designed to be rugged. The PST Reaction does well on paved runways, with its heavier weight and higher landing speeds.

That big, old wing does something else well: set up on approach. This is a major issue for jet models, because they tend to have long, flat approaches, resulting from the lack of a propeller to act as a speed brake.

A propeller’s rpm and pitch tend to slow a model to a set airspeed, allowing the pilot to set the throttle position for the speed needed to fly; that is not so with a turbine-powered model. This is when good airframe drag helps the pilot, and that is what the Reaction 54 offers. Its low-aspect-ratio wing and thick airfoil allow the pilot to confidently slow the aircraft on approach, which sets up a nice angle of descent that can be controlled by throttle. The Reaction has a nice elevator-input linear feel; it slows and flares for landing in a predictable manner.

Next on my list of introductory jets is the Boomerang series. These models are available in various sizes, and each has its own set of advantages. The original Boomerang is an ARF made from balsa. It is nice for 54mm-size turbines. Many jet modelers have obtained their turbine waivers with a Boomerang. It’s a good little sport jet for flying at all fields, including grass.

Next is the Boomerang XL. It’s a giant-scale, sweet-flying version of the original. The Boomerang Elan is the more sophisticated version of the series. In size it falls between the original and the XL, and it’s best powered with an 18- to 30-pound-thrust turbine. I have enjoyed flying this jet, and I have found it to be good for new pilots. The Elan has a neat flap system; it provides extremely high drag, helping the model set up a good approach speed and associated rate of descent that can be controlled by throttle. With the flaps extended, those who like to dive to the end of the runway and then fight that runway-length flare can even get away with that sloppy technique. I prefer the Elan among the models in this series. It is a good introductory jet and is also a good sport jet.

I would be remiss not to mention the two fixed-gear jets: Kerry Sterner’s Facet and Laser Design Services’ JetMach 60. Both have proven to be effective, especially on grass fields; they have durable landing gear setups. These models are also constructed from balsa, are simple in setup, and are proven designs.

Your runway situation should greatly influence model selection. A grass runway will limit your options but not eliminate you from jet modeling. I have made more than 150 flights from grass runways, all with the appropriate jets, and have had no landing gear issues throughout all those years.

Be aware of the approach side of the runway; look for obstacles. Jets do not slow for landing and descend as steeply as most propeller airplanes. Trees on the approach end are a problem.

I preach to all new jet modelers how critical the approach is to making a good landing. A big part of what makes all of the preceding so good as first jets is that they have terrific low-speed handling characteristics, so you can concentrate on developing good approach speed control, or good angle-of-attack control.

Sailplane pilots probably know what I mean. They push their models at high cruise speeds to fly from thermal to thermal, and then they slow the aircraft by increasing the angle of attack with up-elevator trim to circle in the thermal.

If those pilots tried to fly between thermals at this greater angle of attack and slower speed, the sailplane would be descending at a steeper angle. By the time it reached the next thermal, it would have lost considerable altitude.

That’s what you try to do on landing approach: slow the model, increase the angle of attack to increase the drag, and maintain enough speed for good maneuvering, for turning and final flare.

So what about those sport jets you might hear so much about? I left many of them out, but two good designs are the Bob Violett Models BobCat and the Composite-ARF Flash. Many pilots use them as introductory aircraft; some are successful and some are not.

Don’t consider using these models as first jets unless you have a good runway. It should be smooth, long, and preferably paved.

Yes, I know that an experienced modeler can get a BobCat in and out of a 300-foot runway—I do it with mine all the time—but I’ve been flying that design for more than 200 flights. Those are maximum-performance takeoffs and landings.

That type of model offers much faster speeds, but associated with those are faster landing speeds and the need for better approach control. Allow a BobCat or a Flash to glide in at a slightly fast or low angle of attack, and you will be rewarded with an extremely long flare using a couple hundred feet of runway.

Try to rush that landing caused by the botched approach, and you will tear the gear out of the aircraft as it hops and skips off the runway. You must slow these models to land them.

Sport jets make wonderful everyday models; they are simple, durable, and a joy to fly. They keep our skills up for flying scale jets—especially on landing, since you must fly a proper approach to get consistent landings.

I hope that the preceding provides the aspiring jet pilot with some insight into where to begin when selecting the first model. Consider your experience, your flying style, and the runway you intend to use.

Then go out and talk with some jet fliers in your area. Their experience should go a long way in helping you make the best choice.

On the subject of new jets, I have to mention Dave Rigotti’s latest creation: his Over Reaction. Talk about a load of balsa; this thing is unreal! It is a 15% enlargement of the original Reaction 54.

Now Dave is the consignor of Reaction 54s. He had the original from the kit powered with an MW54 turbine, then he created an 85% version powered with an MW44, and now he has the Over Reaction that is powered with a JetCat P120SE turbine.

Bruce Tharpe, the Reaction 54 kit’s designer and manufacturer, has been supportive of Dave’s endeavors. The Over Reaction is cool, weighing in at 29 pounds—just right for the big wing on this aircraft.

Dave gave me the honor of flying this jet. Man, I love flying his airplanes; he sets them up right. We are old Pattern (RC Aerobatics) fliers, and we like the same things in our models’ setups.

The Over Reaction was instantly a pleasure to fly, upright or inverted. That large wing loops equally well either way.

My full aerobatic routine from takeoff left some modelers scared for Dave, but I guess he has gotten used to my flying his models. When I was finished, he simply asked how I liked it. It was fun! It flies straight and true, pulls and pushes honestly, and is plain sweet to fly.

Hey, Dave! When can I fly it again? The big Over Reaction flies just like the Reaction 54, only bigger and better.

Sources

Transcribed from original scans by AI. Minor OCR errors may remain.