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Old Nov 12, 2012, 06:41 AM
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Leeds, UK
Joined Dec 2003
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Second flight last night, ended up putting a quite large left rudder adjustment on the push rod, flies straight now but doesn't seem a very elegant solution. Rechecked the wings and can't see any warp.
I also stuck a keychain camera on top of the canopy, angle turned out to be wrong, but essentially it worked. Also felt a little more stable with the extra weight, but that might also be me getting more used to it.

Is there anything else I could look for to work out this pull to the right?
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Old Nov 12, 2012, 04:24 PM
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Gosford, Australia
Joined Jan 2006
2,620 Posts
Heres mine with my beetle. Syd mine also has left rudder imput. I found that the original rudder size inadaquate so I made it full length. Even with the full length rudder it still has imput to the left . I might be wrong but the torque from the motor makes it pull right hence the input of left rudder.

Bx
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Old Nov 12, 2012, 04:47 PM
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Leeds, UK
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Thanks for the reply!
Good to see the fpv setup there, I was wondering about that.
That beetle quad looks awesome.
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Old Nov 14, 2012, 05:08 PM
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United States, FL
Joined Feb 2012
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Ok, so today I finally tried flying the HK Atom in the most perfect conditions. After almost losing it in thick thorn bushes hundreds of feet out, I miraculously got it to fly towards me and land. I have to say this is the absolute worst plane I have ever flown. In stock form there is almost no rudder authority and it easily gets caught in a turn that is almost impossible to recover from.
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Old Nov 14, 2012, 08:56 PM
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Gosford, Australia
Joined Jan 2006
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Kov your spot on with your assesment. I did the full length rudder mod and it did wonders from the original. Thats the only mod I have done. Give it a try.

Bx
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Old Nov 14, 2012, 10:47 PM
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Quote:
Originally Posted by Boxhead View Post
Kov your spot on with your assesment. I did the full length rudder mod and it did wonders from the original. Thats the only mod I have done. Give it a try.

Bx
I just did your mod, with the rudder 2 twice as big as the original. I really hope it will fly better now, but I'll have to wait until tomorrow to test it out.

This plane seems to be a case of the designer never actually flying the aircraft before production.
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Old Nov 15, 2012, 01:05 AM
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Leeds, UK
Joined Dec 2003
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I took mine out again yesterday, it was a bit breezy, the atom got blown around a little. I shifted everything around so I could stick a small camera to the canopy, and the extra weight did have an effect, couldn't get much height. Otherwise I've found the left rudder adjustment has helped a lot. It does seem fairly easy to turn too hard and cause it to drop, but even a couple of meters off the ground is plenty for it to recover. I've had a few close calls where it brushes the long grass :-P I wonder if the small rudder is to help reduce the chances of that happening.
Going to try making it larger though, the extra control would be welcome!
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Old Nov 15, 2012, 01:17 AM
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New Zealand, Auckland
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Quote:
Originally Posted by kov16 View Post
. I have to say this is the absolute worst plane I have ever flown. In stock form there is almost no rudder authority and it easily gets caught in a turn that is almost impossible to recover from.
Me & my friend have no problems flying ours, this is in wind (too windy for a loop)
HK Atom RC plane (0 min 57 sec)


The rudder is fine, just needs some airflow over it, give it a blip of the throttle.
Its a $40 plane.Bank & yank.
Its not perfect, but thats its charm. Its alot more fun to fly than a 'well designed' plane.
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Old Nov 15, 2012, 02:00 AM
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Bristol,UK
Joined Feb 2007
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In my opinion, they should have junked the rudder in preference to a single aileron servo driving the control surfaces via imbeded snakes as they have on the mini swift. Much better control and easier for a novice to raise a wing & line her up for landing.
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Old Nov 15, 2012, 02:11 PM
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Leeds, UK
Joined Dec 2003
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Just having a look at possible aileron mods, and I noticed the space on the underside of the wing has a shaped bit of foam, exactly the right size for a servo. Maybe it was considered early in the design?
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Old Nov 15, 2012, 02:59 PM
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Bristol,UK
Joined Feb 2007
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Maybe. This post shows where I installed the aileron servos. http://www.rcgroups.com/forums/showp...&postcount=257
Easy and worthwhile mod.
Andy
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Old Nov 15, 2012, 04:27 PM
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United States, FL
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Well, I tried flying the atom with the new rudder mod and it still flies just awful. I've made sure the cg is correct on the spar, but it refuses to fly normally. As soon as I give the slightest up elevator the plane becomes wildly unstable and falls out the sky. It couldn't be a lack of motor power because it's still flying at a high speed when this happens. I thought maybe it's to tail heavy, so I put some pennies in the front and the same thing happened. I give up on this plane, it isn't worth the time and effort to get it to fly.
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Old Nov 16, 2012, 02:29 AM
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Bristol,UK
Joined Feb 2007
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That's really odd. I had to give full rudder (unmodded) and no up elevator for the Atom to bank hard in a downward direction.
You say that with the "slightest up elevator the plane becomes wildly unstable and falls out the sky" Does it rear upwards, cannot maintain airspeed, stall & then drop to the left or right? Does it do it on the glide or just when under power?
Firstly, check that all your control's are moving smoothly with no binding then check the elevator servo for action. Is the tx input proportional to the servo movement. Try this at range as well with a helper. You might have a duff servo.
Next, check the plane for lateral balance by holding the tip of the nose and tip of the tail boom and see if she drop either side. Add a small amount of weight to the other wing tip and try again. Repeat until she stays level. Next, check that the boom is straight and the horizontal stab is level with the wing. If badly twisted then elevator input will act like a rudder and cause the model to go both up & to either left or right.
That's all I can think of but perhaps someone else can add something.
Andy
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Old Nov 16, 2012, 05:03 PM
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United States, FL
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Quote:
Originally Posted by headlessagain View Post
That's really odd. I had to give full rudder (unmodded) and no up elevator for the Atom to bank hard in a downward direction.
You say that with the "slightest up elevator the plane becomes wildly unstable and falls out the sky" Does it rear upwards, cannot maintain airspeed, stall & then drop to the left or right? Does it do it on the glide or just when under power?
Firstly, check that all your control's are moving smoothly with no binding then check the elevator servo for action. Is the tx input proportional to the servo movement. Try this at range as well with a helper. You might have a duff servo.
Next, check the plane for lateral balance by holding the tip of the nose and tip of the tail boom and see if she drop either side. Add a small amount of weight to the other wing tip and try again. Repeat until she stays level. Next, check that the boom is straight and the horizontal stab is level with the wing. If badly twisted then elevator input will act like a rudder and cause the model to go both up & to either left or right.
That's all I can think of but perhaps someone else can add something.
Andy
Good thing I didn't give up because I found the problem. The servo for the rudder was junk and it had a noticeable delay from input to it actually moving. That wasn't the only thing wrong, the rudder would not go back to center even with a high quality servo installed. In order to solve these problems, I put a 3 gram servo all the way to the tail for the rudder with a much stronger pushrod. Now the HK Atom flies really well! The only thing is that it doesn't climb fast but it's not supposed to be a powerful plane.

I will post a photo of my setup once I get around to it.
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Old Nov 16, 2012, 08:21 PM
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United States, FL
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Here's what my setup for the rudder looks like. I used hot glue for the hinge, works much better than tape.
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