Anyone flying the Hacker Decathlon EPP Trainer?

I just ordered one so I give some flying members a taste of RC flying. I've been flying fully-airobatic planes for years but want something forgiving for my 11yo kid, dad-in-law, and others to learn with. I have a motor and lipos. Ordered a few more servos, Rx, ESC, and some bigger wheels from HK.

-l2t

I had one simular. I ran it on a 24g outrunner and kept it light, so it would fly slower for beginners. I've been thinking about getting another and running a 16 gram motor.

I think I'm going to use 50g 930kv that spins a 10x4.7 on 3S. It has a lot of pull but not much speed. I might also have a 1200kv bell style motor that spins a 9x6 which is another option.

Either will I'm sure have plenty of pull. Both were on my Quickstick 1meter sport plane which is the same size as the Decathlon. I should be able to run at trainer speed at 1/2 throttle and be able to land a bit over walking speed.

-l2t

I built a Hacker SuperZoom 40"er, real light. I used three 6g servos, a 24g outrunner, 1300kv, 8x6 prop on a 910 3 cell lipo. Without rudder or landing gear(grass lander), it ended up at 10.5ozs flying.
It hand launches vertical, lands slow enough to catch, flys in a small area, even indoors, turns, loops and rolls very tight and will fly in 20mph winds.
Keeping it light gave it lots of power to weight and a slower stall speed.

I built it over the last week or two and maidened it two flights today.

Here's a review--

It must be an older design. It's designed for a 6V brushed motor that sits behind the firewall. I modified it to take a 50g brushless by moving the firewall back about an inch. The nose is narrow so you wouldn't get one of the wider disk-shaped brushless motors in the nose and would have to put it in front. . It's also built to fly on a rack of five or six NiCads. I modified the battery compartment to take a 1100mAH 3S and added a velcro strap to hold the battery in.

I used a 10x4.7 on the same motor in an aerobatic plane. I decided to under prop it and put a 9x4.7 on it to get a longer flight, more scale-like flight, and more of a trainer behavior.

The wings have basswood spars only on the bottom. Since the slot was cut for a rectangular piece of wood, I used the stock spar. One other mod I made is, I slit the top of the wing about 1/8" and pushed in a 1mm carbon rod the entire length of both wings and CAed it in. That about doubled the stiffness of the wing.

I had some short pieces of 2mm carbon rod around so I used a few inch piece of that for the elevator joiner rather the the little piece of wood it came with.

The build is pretty easy but it is not an out-of-the-box ARF. The equipment compartment is tight but efficient. You can just get two 9G servos and an Rx in it. I used an Orange Rx. ARt6110 would fit a tad easier.

The landing gear would be worthless on grass. The tiny wheels would barely work on pavement. I made a new landing gear out of thicker wire and put 2.5" wheels on it. One mistake I made is I only increased the height and width of the landing gear by 1/4-1/2". Even with the 2.5" wheels, the prop barely clears. If I try to taxi around slowly, the prop hits the grass and paddles the plane around in a circle.


I know they make a 1.2meter cub now. It was a $150 (too much without gear) but now it's down to $100. Bigger is always better with a trainer so that might be a decent option for anyone that wants to spend more. The 1.2m cub is a newer design. I do not know but it may be designed for more modern gear (brushless & lipo). I'm sure the 1.2m plane would be better visibility wise as a trainer but the 1m I'm is adequate.

The instructions are all in metric (mm) and I love that. Way easier than inches and fractions.


On flying. It's as expected, docile. It climbs okay even under propped. It will inside loop. I couldn't get it to outside loop with the power I had. I could do a slow barrel roll losing some altitude. It did nice hammerhead stales. Lazy 8s on the deck are fun.

On the controls, it's been a real long time since I've flown a dihedral plane with a flat bottom airfoil. The ailerons and rudder channel end up both doing almost the same thing. I fly Mode 2 but messed around with roll/pitch on the left stick and elevator on the right stick for a while. It likes rubbing your belly and patting your head until you get used to it. It's not aerobatic but it is fun to noodle around. The control surfaces on the tail are small compared to an aerobatic plane that size so you can't get too aggressive.

-l2t