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Old Dec 11, 2012, 12:33 PM
shahram72 is offline
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I put blue masking tape on the glued surfaces of servos glued into foam, so if I need to remove them to put in another frame, I can start with a clean servo.
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Old Dec 11, 2012, 07:55 PM
Beanz is offline
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I used Araldite 24 hour epoxy glue on my old AXN's spar covers (and also to glue the wings in) over 3 years ago and even after many scarily high speed manoeuvres, stall turns, spins and rolls plus a fair number of hard 'landings' (the ones where you grit your teeth- you know- crashes) and having spent over a week high up in a tree in all Australian weathers (don't ask) the wings and spar covers, in fact everything I glued, is still as firm as it always was.

Then again, I started in this hobby in the 70's before the more modern glues were readily available so I suppose I'm used to it. It adds a little weight but in my opinion it's well worth it due to it's strength.

I know some foams apparently don't like this type of glue and maybe I've been lucky but as I say, it's certainly done the trick for me- and on many of my planes.
Old Dec 12, 2012, 06:09 AM
AlastairL is offline
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I had an interesting one at the w/e.

Had flown the AXN a couple of times, with reasonable control, and no trim issues, after I adjusted for slight nose heavy. Still only a few(~5-6) flights since upgrading from the Champ.

After finding that the roll rate was slow, (yes I know that is typical) I was advised to max the aileron throws. Did this by moving pushrod to the closest position, and offsetting the servo horn on the splines, to overcome the "AXN too short pushrod" syndrome. Also increased travel on the DX6 to max out servo throw.

To the club this w/e, with the local instructor, and glider guru, I was advised also to dial in ~ 40% differential. Pre-flight showed all sufaces neutral, and operating correctly.

Launched with him watching, and things got wierd.......... Under power-off glide, a/c had a consistent roll to left, so we trimmed to neutral in glide. But on throttling up, suddenly developed a strong RIGHT roll issue. After barely saving it, we worked on both aileron and rudder trim to get some sort of cross trimmed neutral, but still getting significant opposite roll between p/o glide, and power on climb.

Gave up and got it down in one piece. Other than the visible trim on the surfaces, no evidence of a cause. Glider guru reckoned there was twist in the wings, and that was cause, but to my eyes it seemed v slight, if at all visible.

Anyway, recharged, and re-set up back to neutral trim visually. Still same throws and diff, and braved another flight. Launched, frantically thumbing in anticipation, and................... no more issue. some aileron and rudder trim required to get neutral h/o flight, but NO evidence of the reversing trim issue with change in throttle.

Got me baffled, (and the instructor too, despite him having seen the whole show.)

No explanations forthcoming yet. I'm just glad to have a flyable bird back, but would welcome any bright ideas from here as to possible causes.

regards

Alastair
Old Dec 12, 2012, 06:47 AM
mutha is online now
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RC Airplane (Recently Crashed)
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Quote:
Anyway, recharged, and re-set up back to neutral trim visually. Still same throws and diff, and braved another flight. Launched, frantically thumbing in anticipation, and................... no more issue. some aileron and rudder trim required to get neutral h/o flight, but NO evidence of the reversing trim issue with change in throttle.
How did you "reset up" back to neutral trim? Therein lies your answer I would think.
Old Dec 12, 2012, 07:17 PM
IamNabil is offline
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AXN roll authority slow


I experienced an interesting roll issue, and I wanted to post it, after reading that it is a known issue with floaters.
I am pretty aggressive with mine. It is so inexpensive that I do things I normally wouldn't with a plane. I was flying it in one of the hurricane remnants earlier this year, and it was really, really struggling with the wind. There was visible wing flutter, and flying into the wind, even at full throttle with a 6x4 prop, it was slow. Suddenly, I could only roll right. Left did nothing. I eventually fought it down onto the runway (I half landed it on the runway, and half bounced it into the cornfield adjacent), and found that I was missing everything between the server and the control horn on one wing. I was super impressed with myself for being able to land it.

So... now that I've told that story, what should I buy for a linkage? I suppose I am looking for a decent linkage stopper and some linkage wire, but I would prefer not to have to bend.
Old Dec 12, 2012, 07:22 PM
AlastairL is offline
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Originally Posted by mutha View Post
How did you "reset up" back to neutral trim? Therein lies your answer I would think.
Not really

All I did was centre the trims back on the TX, and confirm visually that the surfaces were neutral with a/c powered up and bound to TX. In other words back to where I had started at the beginning of the first flight.

Hence the confusion.

Alastair
Old Dec 13, 2012, 02:08 PM
RedLine19k is offline
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is it possible the polyhedral of this plane can cause a lot of trim issues? At launch and full power, there is a lot of rudder authority from the propwash, which is proportionally less at high airspeed when the larger ailerons become dominant. Most people don't consider the rudder for roll trim, so it's easy to get into a cross-controlled configuration that varies with airspeed.

just a theory.
Old Dec 13, 2012, 02:34 PM
hendrnk is offline
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An Aussie in Chicago
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Originally Posted by RedLine19k View Post
is it possible the polyhedral of this plane can cause a lot of trim issues? At launch and full power, there is a lot of rudder authority from the propwash, which is proportionally less at high airspeed when the larger ailerons become dominant. Most people don't consider the rudder for roll trim, so it's easy to get into a cross-controlled configuration that varies with airspeed.

just a theory.
Very true. I have come down after trimming session after a major rebuild and see everything crossed up. Looks like the plane is totally out of alignment. Then after a session of 2 its back to near zero trim.
Old Dec 13, 2012, 11:41 PM
BGR is offline
BGR
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BGR
Foam Junkie
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Originally Posted by RedLine19k View Post
is it possible the polyhedral of this plane can cause a lot of trim issues? At launch and full power, there is a lot of rudder authority from the propwash, which is proportionally less at high airspeed when the larger ailerons become dominant. Most people don't consider the rudder for roll trim, so it's easy to get into a cross-controlled configuration that varies with airspeed.

just a theory.
Well the AXN behaves very differently when transitioning from un-powered to powered flight because of motor torque and the swirling prop wash hitting the rudder on one side more than the other. This can be very confusing to someone that does not understand what is happening and may cause the pilot to constantly want to change the trim. With my setup described below my AXN is well behaved and can be flown like the 70+ mph screamer it is without fighting the tendency to roll.

1. Balance in both Pitch and Roll axis.
2. With power off trim for straight flight.
3. Program a mix to add a small amount of proportional left Rudder to the Throttle channel
4. Aileron throw maxed out, I want all the roll authority I can get.
Last edited by BGR; Dec 13, 2012 at 11:55 PM.
Old Dec 14, 2012, 12:26 PM
Jeandredubois is offline
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Why do you guys complain about the roll rate?
Just mix in ailerion differential - more up than down
So when turning right, the right ailerion will move up to max position &
the left ailerion only 60% down (depending on your choice) & vice versa

Mine is set up like that & i mixed in the rudder & my axn rolls easily twice per second
& straight
Old Dec 14, 2012, 12:37 PM
chucksolo69 is offline
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Yeah, I don't understand why so many are having issues. I have mine trimmed to fly straight and level at about 50% to no throttle. It does tend to dive at 100% throttle, but that isn't a problem up high; I have added a little "up" elevator mix to my throttle.. I have not experienced the roll issues you guys are talking about.
Old Dec 14, 2012, 03:22 PM
RedLine19k is offline
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not sure of others, but my point is sometimes the roll from the polyhedral wing is stronger than the ailerons. At a certain speed, full left rudder and full right aileron might be "straight and level" but hardly trimmed. A polyhedral wing won't crab*.

Next time you're up, kick full rudder or full aileron.. see which one is more violent. Of course, once you have throttle/rudder or even rudder/aileron mixes, you are basically retrimming thru the envelope. That doesn't guarantee there isn't still cross-controlling, only removing the wingtips will prove that.
Old Dec 14, 2012, 07:29 PM
skellator is offline
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9W2DLR
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Originally Posted by chucksolo69 View Post
Yeah, I don't understand why so many are having issues. I have mine trimmed to fly straight and level at about 50% to no throttle. It does tend to dive at 100% throttle, but that isn't a problem up high; I have added a little "up" elevator mix to my throttle.. I have not experienced the roll issues you guys are talking about.
maybe you didn't crash it enough hehe, mine out of the box she fly awesome but after few occasion darting to the face of a hill near my flying site it does not fly that well anymore but fixable!!
Old Dec 15, 2012, 12:37 PM
gooby is offline
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hjukhjuk
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If I buy the kit version without any motor, can I put a Turnigy D2826-6 on the stock mount? And does the plane come in two halves or one piece?
Old Dec 15, 2012, 01:12 PM
hendrnk is offline
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An Aussie in Chicago
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Originally Posted by kovs View Post
If I buy the kit version without any motor, can I put a Turnigy D2826-6 on the stock mount? And does the plane come in two halves or one piece?
It comes in 1 piece unfortunately. Its a pain to split but doable.