We had a group fly at the field yesterday of a design from the seventies... a .40 size Alley Cat. It was a low wing intermediate pattern type plane and a good flyer and one of the favorite planes in my memory. A friend had one in his attic and offered it a while back and I thought it would be nostalgic to fly one again and got it flight worthy and flew it a couple of times and then yesterday the original builder and owner, another who had owned one and myself all got some stick time on it. It was windy but we had a good time.

What turned out to be interesting and hence my reason for this story, another modeler asked why the ailerons were so small on the design. I replied that one had to remember that was in an era before dual rates or exponential. So control movements were restricted to what one could comfortably land with.

The early on stuff was descended from the on/off setups called reed systems
control systems were such that error wa s high in much of the equipment
so- small surfaces made it all a lot more manageable

Also pattern ships were designed to compete at a somewhat constant speed and the design was to give a roll rate appropriate for competition at those speeds. Also wing and control surface design, as well as building technique, can make even smaller ailerons much more effective. Most newer sport planes are designed for more of an extreme flying style, and as said before expo and D/R are standard on most radios now.

Not sure if this is the correct thread but will give it a go. I am planning on scratch builing (from plans via RCM) an Akro Special (pattern ship) 66" w.s. Power 61 size.
I received the plans and noticed that the thickness of the wing at center root is 2 1/4". I plan on a foam wing (as per the plans) and a foam stab. I had plan on using bead foam from Lowes which measures 2" thick. So I plan on altering the tickness of the wing by 1/8" on each side while maintaining the same symmetrical shape . Any thoughts on my plan.Much appreciated.

You will have a hard time keeping weight down on THAT size model TheRCM plans are also ,usually quite "sturdy."
I would go for a 12% root and a 10% tip and use 6-8 lb balsa sheeting and Gorilla glue sparingly.
One piece wing?
If so - no spars needed

To: RHM- I was not quite sure if you understood my question re: Akro Special modification. I wanted to cut my foam wing from a 2" thick piece of beaded foam. That alters the overall thickness by 1/4" . These foam wings and stab will be sheated with 1/16" balsa. If I keep the same symmetrical shape of the wing, will cutting the overall thickness by 1/4" produce any bad effects? All I can imagine is with a thinner wing it may fly a bit faster and perhaps need a bit more power on landings. What is your thought on this?

as long as the wing is strong enough - don't be concerned
measure the total chord and total thickness
The thickness at highest point will be -likely 12-10%
using 6-8 lb A grain GOOD balsa and attaching with Gorilla - -a thin combed coat - the strength should be fine
using lighter wood -the balsa strength goes downhill- fast -
As for going faster - forget it -the % means little
But if you keep the plane light -it will be overall- a much much better aerobatic setup
Weight is THE enemy Many of the plans in that size are extremely heavy for the size .
It is physically impossible to build that design too light or with a wing too thin
And the landings will get easier with the lower weight
I have done the ARFS of this basic design for magazine article yers back and typically they suck- too heavy
But scratch built with low wing loading- a terrific model.