ARTF or not ARTF Lucky Star

[Chinesespaceman_]

Hi,

 I have just finisehd building a so called ARTF model "Lucky Star" purchased complete with Tiger .39 engine. I would like to post some observations that I discovered along the way which I hope will help anyone building a similar model:

1. The hinge tabs for the control surfaces are really flimsy, better to buy some proper hinges and pin them before you start to build.
2. If you follow diag 2 in the destructions you will just have bonded your wing together with the opposite dihedral. The plywood wing joiner is pictured upside down. Dry assemble first to check.
3. The aileron servo mounting is nothing short of criminal. Although suspicious I am new to RC flying and was stupid enough in my eagerness and tried this. The balsa blocks are epoxied onto the wing skin (1/16th balsa) so after 30 seconds of flight the plane did a barrel roll. Luckily my experienced test pilot (cheers Ken) managed to bring it down safely.
4. Before you start to assemble and bond the wing, mark out and cut the clearance for the servo and servo rails as this is much easier when working from the end of each wing rather than working into the blind slot when the wing halves are bonded.
5. I have modified by cutting away the wing skin and epoxy 1/4" hardwood posts vertically in, right down to the top wing skin.
6. These were then sanded level with the inner wing spars, or as close to as possible.
7. Then I prepared 2 x 3/8" hardwood bearers to replace the balsa itmes from the kit, drilled these and counterbored to get the screw head below the surface. These were then screwed into place, bedded in epoxy, the vertical posts having been pre drilled to prevent splitting.
8. Once both bearers are in place I sanded level and checked with a straight edge to make sure no twisting of the servo.
9. The servo was then mounted as normal.

[Chinesespaceman_]

I used 2 x bicycle spokes for to replace the control rods, as the kit ones don't have threaded ends making adjustment impossible. 

1. The undercarriage, vertical fin and stabilizer i left to the end to assemble, purely to prevent damage and make easier handling. When assembling these everything was smooth, however watch that the bottom of the rudder doesn't rub on the fuz.
2. The undercarriage straps are a bit mickey mouse and really could do with stiffer rods and a better clamping system, this will be a later enhancement.
3. The fuel tank caused me to sctrach my head. In the end I epoxied some bearers behind the firewall (13mm behind) carved out and spaced to snugly hold the neck of the bottle. I drilled and tapped out the sheet metal inner plate to M4 as it stripped the thread when tightening the bung.
4. The ali tube I bent the top most one to reach almost the top of the tank and used this as the exhaust pressure feed. The clinker was positioned to allow free movement all around the tank and reaching as close to the end of the tank as possible. When filling I use the 3rd tube and disconnect the pressure tube at the exhaust as the breather / overflow.
5. I used wing tape / rubber between the tank and the rear bulhead to give a close fit and surrounded the tank with foam behind that to prevent any movement.
6. Make sure that the ali tubes do not protrude through the firewall otherwise they will interfere with the nose wheel steering rod.
7. The engine mounting screws in the kit did not fit through the Tiger engine mount holes so I used some correct size (M3 i think) capheads.
8. Ah the good old servo adjusters. When fitted these should move freely on the servo arm and without any slop. I had to file the servo arms down to 1.7mm thick to achieve this. I also used lock nuts for security. The little grub screws are of dubiuos fit with the allen key. I replaced with better quality screws and a decent allen key.
9. The positions for the servos were more or less okay, although the rudder servo rod isn't routed in line with the servo arm, but is okay.
10. I fitted the battery in front of the receiver and fitted the receiver vertically
    The battery fitted flat underneath the throttle servo
11. I glued some bearers in place on either inside of the fuz and above the receiver, so that when the receiver is in place with foam on top, a balsa strap (old piece of trailing edge) holds it all in place.
12. Another thing, the spinner supplied in the kit has too large a hole for the crankshaft of the engine so cannot be use dwithout turning and fitting a sleeve.
    Also, the wheels have to be drilled out to fit onto the undercarriage rods.

13. If I think of anything else I will add, any questions please feel free to ask

All the best

Gavin

[Chinesespaceman_]

[Chinesespaceman_]

[Chinesespaceman_]

Had another flight yesterday with the revised aileron servo mounting. The plane trimmed out nicely and flew really well. What a delight compared to a 3 channel with rudder only.

Only problem experienced was a really audible flutter when in a slight dive, and I don't mean anything aerobatic, just a shallow dive. My instructor brought the plane in and we checked it over, all okay, nothing falling off, control surfaces all okay.

Took it up again, got some height and let it drop from a turn, really bad flutter again.

Looking at the torsion bar set-up that go through the wing and into the ailerons I can see the potential for problems, there is so much stiction and I guess potentail for slop. So what do i do?

Either way the rods have got to go, so it is either separate servos, control rods and horns, or maybe a bell crank? Will have to have a think about that one.

Also, the undercarriage is really not up to the job, distorts and vibrates really badly on landing, so I can see these bits getitng an upgrade too.

I do appreciate this is only a trainer, but it should still be airworthy and not an accident waiting to happen.

The other high wing trainer at our field, a "Arising Star" is a much better kit out of the box 

[Chinesespaceman_]

HI,

Added the separate aileron servos and conrol rods, soldering the rods to give me a steel clevis at each end. Flew perfectly although had to reduce the rates to 50% on my Futaba 6ex tranceiver. At full rates the plane flew really reactivley, you could see every minor aileron input.

The landing gear is like rubber, the nose wheel deforms so much on every landing that the propellor hits and stalls the engine, making a  touch and go very dodgy.

The Super Tiger 38 motor is brilliant picks up well on the carburation and allows touch and goes for a learner like me

[Chinesespaceman_]

Hi for the last time in this thread..............

The Lucky (or maybe not so lucky) Star is no longer. After 3 flights on Saturday the wings folded and the fuselage complete with 1/2 a wing plummeted to earth, burying itself in the ground. The fuselage, wing and motor were all written off. I was able to recover the radio gear and tank...................

So, 2 words of caution:

1. do as i was advised after the carnage and make sure to use a wing bandage when joining the wings. This means stripping back the covering, but worth the effort I think.
2. Don't try getting too over enthusiastic with the aerobatics with one of these flat bottom winged models.

So, I'm off to get hold of a Seagull Boomerang with semi symetrical wing and a few lessons under my belt

Gavin

[colin milne 2]

Hi Gavin,

I have built and learned to fly with the Lucky Star.

I found the instruction to be fairly easy to follow and could not understand that you would have considered bonding anything dircttly to the covering as the assembly manual indicates that you should strip this before bonding. Asregards to the wing joiner It may well be a poor illustration but it would be immpossible to asemble the wing the wrong way round as the root ribs are splayed and this would leave a gap it the joiner was introduced the wrong way.

I have flown this trainer for some 4 months an indeed passed my "A" cert with it. I have had  2 Arc Ready 2 's  and 2  Nova 40's but this was by far the most forgiving of all the trainers.

I do agree abouit the control surface hinges. Although this is a budget priced trainer the manufacturer could have made the model better value for mony with just a few upgrades that wouls have put a couple of quid on the cost but would have taken the model up o a better class.

This was bourn out when it shed an aieleron on a tight turn and hit terra fima. demolishing the front end and snapping the wing at the joint..

Although I have progressed beyond a trainer I am repairing the model as my daughter intends to learn to fly.

Colin

[Kelly]

Hi Gavin,

Your pics have been "moved or deleted".

The Boomerang is a great choice.

[Kelly]

Good build blog .

Boomerang build blog

Forgot to say the U/C is a bit of a weak spot. otherwise a great model.

Kelvin

[Chinesespaceman_]

Yeah,

sorry about the pics, i removed them from the host server.

Still maintain a very poor model when compared to the Seagull Arising Star or Boomerang

Happy flying

Gav