Stevens Aeromodel Kits

Front top view of the Carte Postale

Front top view of the Carte Postale

Once upon a time in the world of radio control modeling, say prior to around 1990, virtually all RC model aircraft were constructed by their owner.  There existed a few custom builders who would custom make a plane to order.  But there were essentially no quality ready to fly aircraft available for the general model flying public.

In this past era kits reigned supreme.  As just about everyone had to construct their own model (and around 95% were powered by internal combustion engines) there was available an incredible range of high quality model aircraft kits for every type of flying and builder.

Rear view of the Hummingbird light sport aircraft

Rear view of the Hummingbird light sport aircraft

With the incredible recent advances in almost and ready to fly RC model planes, the number of kits being produced has dropped off drastically.  Sometimes is can be a challenge even finding a kit of an aircraft that you would like to construct.

With the advent of Computer Aided Design (CAD) and laser wood cutting technology the door is now opened for small companies to design, produce and offer quality radio control model aircraft kits.  The power of CAD and laser cutters allow even a single person operation of offer a variety of worthy airplane kits.

Detailed view of the nose section of the Stevens Aero 1919 White Monoplane

Detailed view of the nose section of the Stevens Aero 1919 White Monoplane

A superb example of this new aspect of the RC kit scene is Stevens Aeromodel.  Stevens Aero offers a wide range of sport and indoor micro flyers using a similar approach:  detailed full scale CAD plans and an innovative tab and lock construction process enabled by the precision of laser cutting (within 0.003 of an inch) using top quality balsa and plywood.  Capping this off is a photo illustrated construction guide (downloaded for free from the website) that describes each and every construction step with a text recap and color picture.

In short, the Stevens Aero design and build approach is such that if you carefully follow the instructions you are essentially guaranteed to produce a successful flying model.

Stevens Aero offers a range of park flyers and indoor RC aircraft.  My experience is with the indoor flyers, so I will focus on that.  One of the challenges of any micro model (those generally coming in at under three ounces flight weight) is getting the correct match in size and weight for the RC electronics and power package.

View of the ParkZone micro electronics. This lightweight unit includes a receiver, two servos and electronic speed control. Available on the Stevens Aero website.

View of the ParkZone micro electronics. This lightweight unit includes a receiver, two servos and electronic speed control. Available on the Stevens Aero website.

SA makes this easy by using the ParkZone ultra-micro electronics and electric motor combination.  The SA micro models are expressly designed for these control and power items.  Using this approach all the components fit properly in the fuselage and work well to produce a model with the correct center of gravity and proper control throws.  All of the electronic modules and motors can be purchased on the website.

As weight is such a concern with a micro flyer Stevens Aero recommends and offers a special light weight iron on covering as well as the mandatory CA glue.  This comprehensive approach aids in keeping the model at the lowest possible weight.  As an example, several of the designs use covering on just the top of the wing.

Strong "balsa box" used on Hummingbird wing to anchor the nose alignment dowel

Strong “balsa box” used on Hummingbird wing to anchor the nose alignment dowel

One of the key elements of a SA model is the interlocking construction process.  The photo construction guide clearly lays the process out.  The individual balsa pieces are all laser etched with an identification part number.  The parts are assembled for the fuselage and wing.  The formers, bulkheads, spars and ribs fit so well due to the precision laser cutting process that the structure is held in together by the friction fit of the tabs.  Once you are satisfied all the pieces are in place and aligned apply the CA glue.  This method is used throughout the model build.

Cowls are produced with this same approach using ¼ inch balsa stacked in place, glued and then sanded to shape.  The electric motor mount is installed during this process with the proper right and down thrust engineered into the fuselage nose section via alignment tabs.  The process really is amazing.

One change I have made with my builds of a SA kit is to glue the wing in place if a high wing mounting is used such as for the Pietenpol.  The directions show a somewhat complex arrangement with mating plywood cabane struts held together with rubber grommets and rare earth magnets.  I have no doubt that this process works. But it looks difficult to ensure the wing is properly set and kept in place after a few bouts of hanger rash.  I instead glue the wing on and take the airplane in one piece to my flying location.

Line up of the various radio control and free flight kits available from Stevens Aero

Line up of the various radio control and free flight kits available from Stevens Aero

The only real challenging process with building one of these smaller kits is installing the control rod linkages.  The directions do a great job of explaining this so take an extra moment to study and think through how it will be done.  If required cut away some of the fuselage bottom balsa to get a good look inside at the control rod runs so you can see what you are doing.

Hummingbird in flight

Hummingbird in flight

The thin music wire used for the control rods is easy to form.  You will make a normal “Z” bend to install one end of the control to the linear servo arm.  Note that the control rods cross inside the fuselage, so the right servo control wire goes across and comes out the left side of the fuselage for either the rudder or the elevator.  One of the fuselage formers will have two small holes that may need to be enlarged.  These openings will act as a control rod guide and prevent flexing.

Balsa build up for Hummingbird nose cowl

Balsa build up for Hummingbird nose cowl

The key insight to the control rod installation process, and I might add a wonderful approach to employ for your own design models, is the use of two pieces of music wire.

The first piece we just discussed and is connected to the servo.  The other piece of music wire uses a “Z” bend to connect to the rudder or elevator control horn.  Where the two wires overlap for an inch or so install some heat shrink tubing and CA to bind the two pieces of music wire together.  This is a super technique to ensure that the control surfaces and servo arms are both perfectly neutral and properly aligned.

BuzzBomb radio control micro flyer

BuzzBomb radio control micro flyer

Most of my SA kits finish up with the center of gravity fairly close to the mark.  Occasionally the models tend to err in being tail heavy.  Be sure to add a bit of nose weight if needed.  I epoxy some solder under the nose and this solves the CG problem.

Be sure to test fly the model indoors in a larger space or outside with zero wind.  The control surfaces look like they hardly move at all but there is sufficient throw to comfortably fly a normal landing pattern.

In summary it is nice to know that there are still folks making quality radio control model kits in this day and age of ARFs everywhere.  A Stevens Aeromodel kit is surprisingly affordable and assembles in just a couple of days.  The result is a very attractive model that is fun to build, flies well and offers something unique to your club flight line.  Do give one a try today!

Author:  Gordon McKay