Hello,

I was wondering if anybody had any input or tips that I should be aware of before I test fly my rebuilt aircraft. I have a phoenix super decathlon and instead of putting a .4 size motor on it (destroyed in the crash) I put a .61 on. The cowling has been cut to fit and a new mount installed. Everything went according to plan. The orginal weight of the .46 os la I had weighed 12 oz and the new engine weighs 22 oz. I had about 2 ounces of weight in the front with the 46 so I figured I would have to add some weight to the tail to make it balance out. I know I need to get the cg right on, but is there anything else? Appreciate the input.

I'm not familiar with the phoenix kit, but I did a very similar thing on a 40 size Great Planes super decathlon. I flew it with an os 40 through one crash, then rebuilt the plane and put an os 61 on it. It was scale...sort-of with the 40, but with the rebuild, I added extra epoxy, new firewall, doublers...a much heavier plane...counting the heavier engine. After the rebuild, I doubt that the little 40 would have done much but taxi it. With that 61, which was a powerhouse, it had awesome performance....not scale, but lots of vertical.

In fact, It had such an excess of power, that I was able to shoe-horn another tank, smoke pump, and muffler on it...rebalancing it of course. It flew great. Even with the extra power, you could slow it down ok, though with the extra weight, it landed faster. I took the wheel pants off because of it...didn't want them snagging our rough field and flipping it at such a fast landing speed.

My brother John said "Hey, can I fly it?"

Well, it went through a stand of trees...and before I could shake my head, it flew back out unscathed...but my already panicked brother dumb-thumbed it BACK into the trees, hitting every tree all the way down a creek bottom, landing in 4 feet of water. Radio trashed..engine survived.

As for your question... balance it right and be ready for a hotter airplane...that's all I know....except I know not to say yes to my brother.

I still have a 16 year old GP decathlon......Now it needs repair....cartwheel on take off.

I can tell you a few things I did wrong.....

1. Had to much elevator input........no dual rates.
2. Wing wash out was the wrong way.
3. Not getting get a good long roll out before pulling back on the stick.

The plane yawed and stalled..........

If it is balanced both ways, throtle up let the tail lift and the plane should do the rest. I find the hardest part is keeping it strait down the run way......(needs wheel toe in) Because the (fus.) is so short take offs can get hairy....give it gentle up elevator.

Hope this helps.

Since this is the most recent post I could find about the Phoenix Decathlon, I'm going to revive it with a new question:

I just bought this plane and want to set it up with Flaperons. Does anyone know what size servo extensions are needed to do this? And do the ends of the servo wires make it to the fuse, or should I get two sets of extensions, one for the wing to the fuse, and one from the receiver out of the fuse.

Thanks, I'm so psyched to fly this plane!!!

Ga, why didn't you just ask when we spoke last, I had my camera out and everything for you when I took the photos of the dot.
Flaperons don't need any more servos or extensions. It's just the two servos you have for the ailerons then flaperons are A radio set up.
I have them set up in my Hots and have them slaved to my elevator. {Don't even think about it or it will hurt your head!!}
I almost never use extensions anymore, I lengthen my servo wires by cutting and soldering to make my leads the length I need.
On the RX I have two 6 inch leads that are always there for my ailerons to plug into so I don't have to plug in and out of the RX.
I have Futaba and off the top of my head I think the flaperons set to Ch. 1 and 6.
READ your instruction book that came with your radio!!!!!!!!

Thanks. I might not have been clear enough with my question. The instructions for the plane say to use a Y-harness for the aileron servos to control both ailerons with one channel, but it appears that it's also serves as a servo lead since the servo wires themselves wouldn't reach the receiver. So I want to plug two separate servo leads into the receiver for flaperons (and so I don't have to plug in and out of the receiver) and that will be long enough to reach the ends of the servo wires. I'm not the best at soldering, so I prefer to go for extensions where needed. So instead of buying a Y-harness, I should buy two servo leads/extensions, and need to figure out how long they have to be for this specific plane.

Or I could wait[:@]

Graybeard, thanks for those pics. I didn't think you went through the trouble to shoot them just for me at the time, but now realize you did.

THANKS!!!

GaRC,

Decathalons, like Cubs, T-crafts and other similar planes all share a couple of common tendencies. The one that causes the most trouble to inexperienced pilots is their tendancy to groundloop.

A groundloop occurs during ground handling (duh...). A short tail and close spaced landing gear on a taildragger are contributing factors. It can happen on take-off or landing, but is more common at take-off.

A typical scenario is the pilot taxi's to the hold position, then advances the throttle to take off. The combo of spiral wash and perhaps other prop effects cause the plane to yaw to the left. The pilot must apply right rudder to counter this quickly, or the plane may begin to roll to the outside of the turn rather rapidly (just topple over on the narrow gear). Depending on the speed at the time, this may result in an embarrassing donut, or an ugly cartwheel.

A few things can be done to reduce this tendancy. First, during the initial roll-out on take-off, hold full up elevator for a moment or 2. This keeps the tail wheel pinned to the ground and gives you rudder authority until you have airspeed for the air rudder to be effective with. Control yaw with rudder stick. Once the plane is moving, the elevator must be relaxed to allow the tail to fly and the plane to gather flying speed, or the plane will pop up, likely stall, and crash.

The other thing is a mechanical tweak to the plane's landing gear. The mains should be toed in a couple degrees. This effectively prevents ground looping. Toed in means that the wheels don't point straight forward, but are each steered towards the nose slightly. If you were to extend a line along each wheel's natural path, they'd cross 10 or 12 feet in front of the plane.

With toed in wheels, when the plane yaws on the ground, the wheel on the outside of the turn is effectively put at a more extreme "angle of attack" to the plane's direction. This tends to slow that wheel and haul the plane back towards on-line. It doesn't eliminate the need to be on the rudder, but it reduces it a bit.

Lastly, super dec's are known to want to land a bit faster than you'd think for a "trainer looking" plane. See what it's stall performance is like at altitude before landing the first time. If it has a tendancy to tip stall violently, (in a stall it suddenly snaps and rolls over instead of simply mushing forward), adding a couple degrees of washout to the wing will help. Washout is twisting the wing such that the tips point down compared to the rest of the wing by about 1-2 degrees. This can be done by holding the tip and root of the wing, flexing it in the desired direction, and then ironing or heat gunning the resulting wrinkles from the covering. Allow to cool and release. The covering will hold a bit of washout with no real trouble. A little bit goes a long way. This aerodynamic feature is what made the Spitfire such a formidable fighter in it's day. Without washout, that elliptical wing would have made the Spit a snappy bugger of a plane.

J