Free Flight: Old-Timers
Bill Baker
1902 Peter Pan Norman, OK 73072
I read all of the soaring columns, and modern sailplanes seem to be going to high-tech stuff like carbon fiber, vacuum-bagged wings, boron, and fiberglass. I like to work in wood, and I am not comfortable with some of the new construction techniques; maybe I'm just too old to change my ways. However, I certainly use modern adhesives, including cyanoacrylates in three viscosities, epoxy glues, glass cloth here and there, and even some carbon fiber reinforcement.
I still like to make basic structures out of balsa, spruce, and bass. It occurs to me that a generation of modelers raised on fiberglass and foam may feel as uncomfortable with stick-and-tissue structures as I feel with some of the new techniques. I am trying to keep their needs in mind when I do this column and not just write for other old codgers like me.
Recommended book
The book I recommend to anyone looking for basic instruction is Peanut Power by Bill Hannan. Yes, it is about peanut (under 13-in. span) rubber scale models, but the same building techniques can be used for larger Old-Timer models. The chapter on propellers is especially good; in fact, it alone is worth the price of the book. I suggest you buy Peanut Power directly from Hannan's Runway, Box 210, Magalia, CA 95954 because they will also send you a catalog of other publications that may well be of interest to you. Peanut Power costs $15.95, plus $3.25 postage; Californians need to add sales tax.
If you are looking for basic instruction on laying out and carving a propeller, I would definitely refer you to the propeller chapter of Peanut Power. Some time in the future I intend to write a column about making folding propellers for rubber models (in which I am prone to use some non-traditional things like cyanoacrylate glues). Some of the books sold by Hannan's Runway are just plain fun to read, as well as instructional. For the catalog only, send them a buck, which will be refundable with your first order.
Kits: Peck-Polymers Convertable and Ace Whitman Albatros
In keeping with trying to help those who are new to Old-Timer construction, I will now discuss in more detail the kits mentioned in my last column: the Peck-Polymers Convertable and the Ace Whitman Albatros kitted by Pharis Models. I framed up my review kits with an eye to "what would give trouble to the new-to-this builder."
#### Ace Whitman Albatros
The Albatros plan is on two full sheets; one with the traditional plan, the other with isometrics and detailed instructions. Really outstanding for this type of model. The propeller shown on the plan is a 7-in. "token," probably supplied as a machine-shaped blank in the original kit, produced in the 1930s by the Ace Whitman Company. The second plan sheet does show an 11-in. contest propeller with instruction on blank layout and carving. The landing gear is long enough for such a prop, which is an important point when choosing an Old-Timer design. In the current kit, a plastic propeller of about a 9-in. diameter is supplied and should be adequate for the sport flier.
Also included is a sheet of suggested changes that make the model more practical. These changes include a removable nose block, a dethermalizer, and provisions to attach the wing with rubber rather than glue. The nose block is the most important of all: for some reason, many of the old plans give no clue on this. Not only do you want to be able to remove the nose block to wind and change motors, but the ability to make thrust-line adjustments by shimming between the nose block and the fuselage is indispensable for flight trimming. I would put in about 1/16 in. of downthrust and about 1/8 in. of right thrust before attempting the first flight.
One change not shown, which I did and suggest to you, is to move the rear attachment point of the rubber motor forward and change to an aluminum tube-through-sheet balsa fill between the uprights in the sides. The rear attachment is moved forward from the position on the plans at the leading edge of the stab to a point nearly midway between the stab leading edge and the wing trailing edge (well, maybe a third of the way on this one); this will reduce the necessary nose weight and thereby reduce the total weight.
You can generalize these changes to most of the old scale and non-scale rubber-powered models. Rubber, being the heavy stuff it is, has a profound effect on the center of gravity. On the short-nosed scale and "realistic" (i.e., looks almost like an airplane) non-scale Old-Timers like the Albatros, moving the center of the rubber forward will considerably reduce necessary ballast weight and greatly improve performance.
I think for best performance the wooden propeller supplied with the kit should be used, but I do think that the model will fly with a 9-in. (P-30 size) plastic propeller, which can be supplied by Peck-Polymers.
#### Peck-Polymers Convertable
When I worked on the wings on these two projects, I discovered what could be a major problem for the less-experienced modeler. The instructions for the Convertable say, "Build the wing over the plan in five parts." It is a very basic structure; however, many people will build a multi-spar structure like this, with the spars in place on all five parts, and then try to join at the required angles by trimming the spars for length and angle. This is something like teaching ducks to march in step.
First, delay adding any lower spar that does not lie flat on the plan. On the Convertable the spar is off of the plan due to the undercamber. Therefore, you do not want to add it until the other framework is complete and off of the board. Now, here is the main point: most problems and warps can be avoided if you first build the tips, with the proper dihedral angle, and then bring up the center panels, and then add the spars to the panels on the tips; add the dihedral to the main panels, and finally build the center panel joining the two main panels. Sure is easier that way.
The problem I had on the ribs was that the printed wood patterns for the ribs show excessive thinning of the trailing edge of the ribs, so that the ribs are not as thick as the trailing edge at the point where they join. That is what I get for watching ball games while I cut ribs. The ribs seem very difficult to handle because of the undercamber and thin trailing edge. I therefore cut all new ones and went to a flat-bottomed airfoil and a somewhat stronger spar structure: I want this ship for fun flying for a long time, and I want a stronger wing.
The one spar on the bottom, while easy and common on many models of the era, is very warp-prone and weak. I put a 1/8-in. square on top and bottom at the one-third chord point; it was easy to add some webbing joining the spars to make a lightweight I-beam. Not authentic, but very practical.
One final note on the Convertable: the fuselage is shown as more than an inch wide at the extreme aft end instead of coming to a point. I think it likely the draftsman made it this way to provide a more stable platform for the stab. I should mention that the modifications for a dethermalizer as well as the removable nose block, wing, etc., are on the Peck-Polymers plans. It is still strange-looking, and, when I compare the Convertable to the original plans as presented in the Zaic Yearbook, it appears to me that the longerons were to be cracked at the leading edge of the stab and replaced with the aft ends joined to a point. Not really important, I guess; but for those who want the max in authentic "like it wuz," check it out.
Final thoughts
The Convertable and the Albatros are both very nice kits. Along with the Peck-Polymers Flying Aces Moth, they are a fine introduction to stick-and-tissue Old-Timers.
Transcribed from original scans by AI. Minor OCR errors may remain.
