Carl Goldberg 1/2A Skylane
OK, I've decided to build another 1/2A Skylane. This time it will be electric. As with the one described below that was powered with a Norvel .061 nitro fuel engine, this one will be built by creating a kit of parts derived from tracing around the original kit parts. Surprisingly, especially for the era, the balsa and plywood used in the original kit are very high quality and the density of the wood is excellent. Of course, the nice thing about cutting parts from scratch is that you get to hand-select all the wood.
A copy of the original plans was obtained off of eBay before I actually bought a kit off of eBay as well. The guy presented the plans as if they were the originals, but turned out to be a cheap copy. The size increased by about 1% or so during the copying, so the parts aren't quite a match to the plans. They do match original plans that I got with the kit, though.
My intention is to replicate the kit pretty much exactly per the original, but I will need to do some modifications to accommodate the brushless motor setup. It will be 3-channel, with throttle, elevator, and rudder. The original plans shows installation for both a servo (very large) and an escapement. If all goes well, I hope to actually use a nano servo to drive a torque rod to control the rudder, per the original. I'll provide photos once it has been done. Unlike the escapement control that provides center and full throw left or right, this will be proportional.
On the .061-powered version, the elevators we separate and controlled by a split pushrod. This time, they will be jointed and hinged along the same line so that a single pushrod can be used.
Here is a tip that makes cutting out the plywood parts much easier where inside curves are required. Use a Forstner bit of proper radius to cut the radii, and then proceed with cutting everything else either with a jigsaw or band saw, and sand to final size. Doing so virtually eliminates any tendency for the plywood layers to pull apart or chip off while cutting. I was actually able to control the Forstner bit positions tightly enough (using a drill press) to not need to sand the inside curves.
As a kid back in the 1960s, I built two Carl Goldberg 1/2A Skylane models. They were intended for a single-channel escapement system, but I never did accumulate enough money for the radio, so they ended up as free flight planes. Both were powered with Cox Baby Bee .049 engines. By today's standards, the kits were very difficult to build - lots of interlocking parts and poor die cutting compounded the problem. I remember tying a string to the propeller and dragging it behind my bicycle, carefully governing the speed to get it to the point where it would just begin to become airborne, then backing off.
A 2-piece elevator was necessary to keep the scale appearance, since the trailing edge of the horizontal stabilizer tapers forward on both sides; that was a real pain because it required a split pushrod arrangement and contributed to a tail-heavy end result. Admittedly, I could have done a better job with both the elevator and the rudder pushrods, so maybe the next time around a better system will prevail. Even with three Futaba micro servos and a 300 mAh battery pack, the model ended up very heavy - and flew like it. The Norvel .061 was also way too much power for it, but better more than enough power than not enough is my motto. The 1/2A Skylane was stable in the air, but landed very fast because of the relatively high wing loading and stall speed. I don't have the flying weight number handy, but it was around 6 ounces over the max recommended by Carl Goldberg, partly due to 2.5 ounces of lead necessary in the nose to balance it. I still have the kit of parts and the plan, so some day I'll build another and use a really lightweight radio system and be more choosy with balsa/plywood selection.
The AMA Plans Service offers a full-size version of plans at a very reasonable cost. They will scale the plans any size for you.
I am now working (very slowly) on an electric-powered Carl Goldberg 1/2A Skylane. MotoCalc software was used to determine which motor/battery combination would be necessary in order to achieve the desired performance. Here is a snapshot of the input parameter screen and of the output performance prediction screen. The data provided for my electric-powered of the Great Planes Spirit (e-Spirit) worked out extremely well, so I trust this prediction.
Here are some construction photos of the e-Skylane
This must be a rare pair - the Carl Goldberg Skylane 62 and the 1/2A Skylane kits
Here is my personal 1/2A Skylane kit. The plans are shown below, and at some point in the future, I'll post photos of all the parts.
Carl Goldberg 1/2A Skylane Plans
AirplanesAndRockets visitor Kim Stricker has been kind enough to send photos of his 1/2A Skylane that he built as a teenager. The paint scheme is modeled after a Missouri Highway Patrol aircraft - quite a nice job!
This is the Skylane 62 kit that I purchased off of eBay a while back. It has since been sold.
Note: The Academy of Model Aeronautics (AMA) sells the Skylane 62 plans:
Here are a couple recent eBay auction ending prices - $292, $305, and $265 for this exact same kit. It is rare to find one for sale.
Note from Bill Mohrbacher: (April 2012)
"Today I saw your CG 1/2A Skylane post. Back in 1964/65 I built one. I was covered with yellow silk and painted with Sig dope. I love transparent finishes. The framework fascinates me, I love to look through it when I am flying overhead, and I am also quite vain and proud of my work.
I always found CG kits to be well engineered. Parts were ACCURATELY drawn and produced (not like Sterling and Berkeley). Material selection was excellent. There was a lot of work in the assembly and you had better know how to contour and block sand, but the final results were spectacular. And the planes were always excellent fliers. Cark Goldberg's experience sure showed in all of them!
I don't know what mine weighed, but it was probably on the light side. Power was a 1964 Fox .049, Citizenship superhet relayless rcv, Mule MK II xmitter, Babcock MK II compound escapement (can't use esc abbreviation anymore for this vintage mechanical wonder), and 2 pencell battery PS. I didn't use the kick up, just rudder and no throttle. I could do loops, Immelmans, Cuban 8s, and barrel rolls; typical RO maneuvers.
Then I got fancy. I installed a MaX 10 RC engine, OS single channel throttle servo and SC rudder servo, Controlaire SH 100 Superhet relay rcv, and 2 more batteries, 4 total. All was well until the first loop and then the balsa wing spar failed. I have always wanted to build another; someday!"