As open space becomes more and more scare in populated areas all up and down the East Coast, the Great Lakes region, and similar sections of the country, free flight activities are increasingly difficult to contemplate. The same goes for model rocketry. All of the fields I used to fly from in the Mayo (Annapolis), Maryland, area when in my teens back in the early to mid 1970s were long ago turned into housing developments, commercial office or retail outlet stores. It used to be a simple matter of loading an airplane or rocket into my 1969 Camaro and driving a few miles to a school yard or an empty lot behind a strip mall, but not so much anymore. Even if you do manage to locate a suitable flying area, there are usually signs posted warning of prosecution for trespassing (often made necessary due to our overly litigious society). School athletic fields are typically cluttered with soccer nets and other permanent structures. Whenever I see photos in articles like this one for a free flight towed glider model, I am struck by the starkness of the landscape in the background. It seems today you need to me in a Midwest farm field, in the High Plains, or Southwest deserts to find ample open areas.
Southwest Champion's Winning Towliner "Honker"
Contest-proven Class A/2 Nordic towline glider designed for windy weather competition appeals to both expert and novice flyer
By M. R. Lipsey
Designer-author Lipsey adjusts his Honker in Southwestern Championship meet at Dallas.
After several years of attempting to fly European designed gliders in the wind and "brick-lifting" thermals of Texas and surrounding states, it became apparent that while Continental types were suitable for Europe, something more was to be desired if a glider was to fly consistently in our weather conditions.
"Honker's" .development was thus begun with three specific points in mind: i.e. (1) to incorporate the necessary stability to tow and fly with ease in our turbulent air; (2) to be quick and easy to build with ample strength to last through several contest seasons; (3) to be an ideal design with which to introduce the novice to towline gliders. Honker fills the bill!
Generous dihedral with a 50% C.G. location is combined with an abnormally large stabilizer to give the glider bounce and quick recovery when upset. The large stab also gives a more positive D.T. when you are trying to get the ship down out of that "brick-lifter" to complete your five flights. The aspect ratio of the wing is reduced below average for strength, warp resistance, and a belief that high aspect ratio wings often keep a ship out of a strong thermal. After observing many gliders, it appeared that when high aspect-ratio tow liners bumped into the side of a thermal, the wing-half touching the edge of the lift was kicked-up violently and the ship was actually thrown away from the thermal. The higher the aspect-ratio, the more leverage is available for the thermal to act upon. Additional side area is built into the fuselage to increase tow stability and to have something to "lean-on" when the glide tightens up with the speed increase generated in a thermal.
Honker won Lipsey Championship award. Glider has helped capture 5 hi-point prizes
The "follow-me" tow hook as shown in the sketch is a gadget which has worked well for the writer. However, this is not recommended for the novice as it requires towing experience to get the feel of this device and to be able to adjust it properly. The original idea behind the moveable hook was to increase tow stability and, properly adjusted, it performs this function. In addition, it was found that this arrangement would allow the ship to be towed in a hunting motion while at the top of the line. Upon feeling lift with the glider overhead, the glider is towed sideways, turning the ship toward its normal glide turn. The glider is accelerated as much as possible at this time. The line is released rather than attempting to release the ship. The acceleration with the ship turning into its normal glide path gets additional altitude upon release with a stall-less transition from tow to glide. Of course, the line must be released from the reel so that you release only the line and are not disqualified for throwing the reel.
The writer feels that lack of knowledge in adjusting a glider to tow properly has discouraged more beginning towline enthusiasts than any other problem. Ninety-nine percent of tow adjustment problems lay in the relationship of hook placement to C.G. There is one ideal hook placement for each glider. This placement is found when the glider tows straight to the top of the line from the point of release. (This also applies to the "follow-me" hook).
Rather than take the time to construct an adjustable hook, it is recommended that a permanent hook be installed with the forward-most part of the hook 1/4" in front of the 50% C.G. location. Then upon completion of the ship, the C.G. is shifted to effect the shifting of the hook, if necessary, and decalage is changed to adjust the glide. A wandering tow in which the glider always recovers and continues to follow you indicates that the hook is too far forward. In this case, the C.G. should be moved forward. (This gives the same result as moving the hook back). A tow in which the glider always turns away or has no tendency to follow indicates the hook is too far back. (Shift the C.G. back).
Construction. The stabilizer and wing should be completed before the fuselage is begun. This sequence will enable you to fit the wing and stab platforms accurately and facilitate balancing the model properly without the addition of unnecessary weight.
The ribs for the stab and wing can be mass produced by making two patterns of each rib and pinning the correct number of 1/16" sheet strips between the patterns. All the strips are then carved and sanded down to match the patterns. Cut the slots for the spars and leading edge carefully to obtain as perfect a fit as possible. Slots too small or too large help create warps. The trailing edges should be notched to receive the ribs. The front of the trailing edges should be raised from your building board with scraps of 1/32" to maintain the undercamber curvature.
The 1/16" x 1/2" shear webs which are glued between the "over-and-under" spars should have the grain running vertically. These sheer webs add tremendously to strength and warp resistance. Don't leave them out!
The 1/4" ribs utilized at the dihedral breaks should be aligned and glued firmly in place along with the other ribs. After completing assembly of an parts, these ribs are beveled at the correct angles to butt join the pieces of the wing and stab to form the correct dihedral angles. Remember the bevel angle for each rib is only 1/2 that of the total dihedral angle. This system of joining parts has been well received by novices.
The fuselage construction is straight forward and should be completed without difficulty. The fuselage should be completed entirely except for the addition of weight and the 1/8" cap sheet over the weight compartments. The model should then be assembled and placed on a scales. Add enough ballast to bring the total weight up to 14.5 ozs. The ballast should be shifted until the C.G. is at 50% of the wing cord. Glue in the ballast and finish.
Adjust your glider carefully, making short tows until you gain confidence with it. Try to maintain a constant pull on the line as you tow. This will require you to move faster as the glider reaches the top. Practice makes winning tows.
Honker Towliner Plans
Full size plans for Honker are part of Group Plan #963 available from Hobby Helpers (1543 Stillwell Ave., New York 61, N.Y.) - 85 cents. Glider has been duplicated throughout the Southwest.
The AMA Plans Service offers a full-size
version of many of the plans show here at a very reasonable cost. They will scale the plans any size for you. It is always
best to buy printed plans because my scanner versions often have distortions that can cause parts to fit poorly. Purchasing
plans also help to support the operation of the Academy of Model
Aeronautics - the #1 advocate for model aviation throughout the world. If the AMA no longer has this plan on file, I
will be glad to send you my higher resolution version.
Try my Scale Calculator for Model Airplane Plans.
Posted July 25, 2015