DON'T COOK YOUR CUB!

[Dillzio]

Hey gang,

Here's an important lesson for all you kids out there, this one's for anyone that lives in a hot climate.

We've been having a heat-wave in Adelaide lately, which means consecutive days over 35 Celsius, generally the sort of weather in which the elderly start dropping like flies if they don't keep well-hydrated and cool. The day before yesterday, it peaked at 37 degrees, normal body temp which I think is about 98 Fahrenheit. Guess who left his plane in the car from the day before?

The main casualty that I'm aware of (so far) is the tail. As far as I can tell the only thing that makes the tail stiff and rigid is the laminate that's glued to it. Once that gets heated up the glue lets go, and the tail warps and swells. The horizontal stabilizer wasn't horizontal any more, it was shaped more like a frowny face , and the elevator wouldn't fit in it's slot anymore, it wouldn't move it all.

My tail was also coated with clear packaging tape, with the edges reinforced and stuck down with superglue, I'm not sure if that mod made it more or less susceptible. At any rate, I've braved a trip into the city (I got up early to avoid the heat) to Model Flight, the only place in Adelaide that stocks spare parts for the Cub. I got myself a brand spanking new tail for $20 Aus, which AT THE MOMENT is about $19 US (good time for us Aussies to by crap from overseas on ebay .

Also got some landing gear, wing struts. I don't use the stock struts, but my pins that hold the struts to the wings have just about had it and they come with it. I asked about getting landing gear for the J3 Cub to put on my cub as landing gear struts, but they said that particular model has never been stocked in Australia, so if us Aussies want to buy them we have to buy from OS.

The other casualty of the heat was the O-rings of the prop saver, and the rubber bands that hold on the wing, the rubber bands had just about started to melt, become tacky and started to stick to each other, and lost all their elasticity. The O-rings on the prop saver had become so loose I could put them on and off with my bare hands.

So, the simply moral of the story is not to leave your Super Cub in the car on a hot day. Treat your cub like pet that you have to take care of, something that you can't just leave in a car on a hot day.

[duck9191]

happend to my cub along time ago, the tail was the only casualty. warped really bad so i just replaced it, rest of the cub was ok.

[patmatgal]

Huh... Makes me wonder now. I try to be real careful about jarring the Super Cub but have noticed that the rudder warps after a while. It's definitely not that I'm flying too close to the sun so maybe it's being left in the car, thanks for the tip!

[Dillzio]

No probs, I just wish I'd read about it before my cub became a casualty! I've already got a small crease in my new tail and I'm not at all happy about it, the perfection is tainted!

I'm considering options for a tougher alternative. I guess buying another tail and reinforcing it might be an option, but it would prob be a bit to thick. Perhaps just remaking it would be the best option, perhaps with 4mm balsa reinforced with resin.

Anyone seen that type of thing done before?

[patmatgal]

Hmm...
That sounds like it would work, if everything were at 90 degree angles it sounds very doable. But do you think it might end up too heavy? How about some CA glue along the outside edge of the elevator and leading edge & top of the rudder, back to the flap?

[Dillzio]

it would be heavier, but balsa wood is pretty light, and as long as you didn't put the epoxy on too thick that wouldn't add heaps of weight either.

Your idea about reinforcing with CA sounds alright. Perhaps laying down a bead of epoxy in sort of a framework for reinforcement would work well. The only problem is that it wouldn't overcome the issue of the glue that holds on the laminate, if that let go any reinforcement you had stuck to the laminate would be useless. What would be IDEAL is having two sheets of 1mm aluminum, putting one each side of the tail and riveting them together, but if you were going to do that you may as well just make a tail out of 3mm aluminum (which i happen to have laying around :-])

It's a tough project, making a robust tail that won't throw out the CG too much. Making something tough and light is never easy. Any weight as far back as the tail will need 3-4 times the same weight on the nose to balance it out. I've got my battery mounted vertically as far forward as I can manage (against the landing gear at the front of the battery box) and I still need weight on the nose to get my center of gravity balanced right.

[Dillzio]

Hey all,

I had bit of crash today, and bent up my new tail :-(

I took it off to straighten and reinforce it a bit. I ended up reinforcing it with bright white reflective cloth tape. I've found that if you run it longways along the top and bottom of the tail REALLY tight it makes the tail quite straight, stiff and rigid.

I'd highly recommend it as a easy and light tail reinforcement.