Did I screw up the wing on my avenger?

Did I screw up the wing on my avenger?
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Did I screw up the wing on my avenger? - 6/26/2007 4:31:42 PM

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From: Redmond, WA,
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I built one last year, love it. Finished the second one yesterday, and realized(after I was done) that I didn't narrow the chord towards the wingtip. What is this going to do for performance. The chord should be around 5" at the tip, and mine is 5 3/4" Curious to see if I notice a difference....

Mike

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RE: Did I screw up the wing on my avenger? - 6/26/2007 5:02:35 PM

The Internet Killer

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I didn't narrow mine either, as long as both wing tips have
the same cord, shouldn't be a big disadvantage, but I could be wrong.

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RE: Did I screw up the wing on my avenger? - 6/26/2007 5:23:16 PM

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I doubt you'll notice much. I take it you're supposed to trim off some of the trailing edge?

At worst, your TE is a bit thin, which could make the aileron mount a little fragile, or it could cause odd airflow around the aileron which might cause wing flexing and/or aileron flutter or a little extra drag. But that's all "worst case", I doubt you'll notice any change at all as long as both tips match (or are at least close).

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RE: Did I screw up the wing on my avenger? - 6/26/2007 5:43:01 PM

The Internet Killer

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Hey, Doc, noticed your in Redmond Wa, if your ever up to a drive they are holding combat
every other Friday evening at Bellair Flyers in Bellingham.

Mr Monty Sir, I have a question for you if I may. My newly repaired avenger rolls left at launch,
flys straight hands off, niether climbs or dives when power is cut, and rolls to the left are fairly axial,
but rolls to the right involve a large dive as it goes inverted. Any suggestions ???
( I should add, it has a single aireron servo)

< Message edited by The Internet Killer -- 6/26/2007 5:45:51 PM >

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RE: Did I screw up the wing on my avenger? - 6/26/2007 5:57:03 PM

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Hmm, that's a rough one.

If it was me, I'd probably ignore the going left on launch as long as the plane didn't also go left in a hard turn or loop.

When I trim fly, one of the most important thing I do is max rate turns left and right. Any oddity in the rudder trim (twisted vertical stab for example) or wing oddities will often show up there with the plane always stalling the same way.

The rolling thing is a little harder to figure, but it's probably one of a couple of things. It might just be your thumb moving off-center a little as you do the roll, and feeding in some elevator.

Assuming it's not that, you might try some vertical rolls, espeically at idle in a vertical dive. It's most likely that you have a something in the aileron travel that's causing the ailerons to deflect unevenly. That uneven deflection is leading to just about a perfect amount of differential for a left roll, but a totally wrong diferential for a right roll. It's not uncommon for me to have a plane that rolls one way better than the other, or is more axial in one way than the other and unless it's really bad I usually don't sweat it. (after all, combat wings often get "dynamically re-trimmed", so a lot of time spent getting it "perfect" can easily be wasted when someone hits the wing and moves stuff around on you).

Which also reminds me, make sure you're wing is on straight and level.

I've also traced that kind of thing to problems with the aileron hinges or a bent pushrod. If the aileron LE can move vertically against the wing TE, then depending on the airflow and the pushrod and aileorn horn arrangement, sometimes servo deflection will rotate the aileron as desired, and sometimes it might move the whole aileron up or down instead, which can do some odd things to the roll. This often shows up as the aileron trim seeming to change a bit in flight on it's own as well, but not always.

Hope that helps.

AJ often reads these forums, hopefully he will pop in and comment on both problems.

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RE: Did I screw up the wing on my avenger? - 6/26/2007 6:02:58 PM

The Internet Killer

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Thank you, Sir.

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RE: Did I screw up the wing on my avenger? - 6/26/2007 6:17:03 PM

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Oh, I forgot, while I do often ignore some left-turn on launch, you might want to look carefully to see if the plane is rolling left, or if it's yawing left then rolling due to the yaw. It happens fast, so you need to watch the nose and get a good, straight launch. If it's yawing left, check the vertical stab for twists and your thrust line. Since your engine is mounted horizontally, make sure the engine mount isn't bent and that there aren't any cracks in the fuse that allow the engine to move.

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RE: Did I screw up the wing on my avenger? - 6/26/2007 9:20:10 PM

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I had the same problem with one of my sscavenger wings, try balancing the plane tip to tail and see if its heavy to one wing tip, not likley to be the problem but possible. My problem was a bit of warp in the wing (Ailerons were not centered to counter the wing, had exaxtly the tendancy you described. Wrecked it once and re glued the center and it was fine, must have taken the stress off the warp... Lay the wing out as it was built and look for a warp or twist

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RE: Did I screw up the wing on my avenger? - 6/27/2007 6:19:52 AM

The Internet Killer

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Nope, Sir Monty nailed it. the fuse had a hook to it (bent to the left).
Some not so gentle pressure straightened it up, just have to remember
to check it before the first flight of the day. It may have contributed to
a kind of a corkscrew action in a right hand roll, but I need to play with
it a little because the aireron deflection is not quite even on both wings
either.

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RE: Did I screw up the wing on my avenger? - 6/29/2007 3:31:16 PM

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I flew the crap out of this plane last night, works great! My other avenger can snap with too much elevator, this one holds its line the whole time. I see that Seaholm has used delrin for the engine mount on the new one, I'd like to have a stiffer mount on mine, after a few flights, it bends to the left...

I think I hooked a buddy on combat last night :-) I built avenger #2 solely to drum up interest, (and have someone to play with)

I've done almost every aspect of R/C, turbines, big 3d planes, helis, gliders... combat is the most fun I've had so far! And for the cost of the turbine jet I built, I could buy 35 ready to fly avengers! Defnitely great bang for the buck.

Mike

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RE: Did I screw up the wing on my avenger? - 6/30/2007 11:57:10 AM

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quote:

ORIGINAL: DrScoles

combat is the most fun I've had so far! And for the cost of the turbine jet I built, I could buy 35 ready to fly avengers! Defnitely great bang for the buck.

Mike

I also have more fun with combat than any other aspect of RC. If it wasn't for combat I probably wouldn't be fly much at all. Just watch the burnout factor.
Once ya really get hooked and start traveling a bit to different events. Building 3 or more planes per event. Watching them all get smeared in one day then going home and doing it all over again can get a bit tiresome. I limit myself to just 5 or 6 events a year so I don't turn it into work.
Have a ball with it. It's great fun!

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RE: Did I screw up the wing on my avenger? - 6/30/2007 5:35:02 PM

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quote:

ORIGINAL: DrScoles

I built one last year, love it. Finished the second one yesterday, and realized(after I was done) that I didn't narrow the chord towards the wingtip. What is this going to do for performance. The chord should be around 5" at the tip, and mine is 5 3/4" Curious to see if I notice a difference....

Mike

The wing doesn't come already in the right shape? That's interesting. Such a small change will usually not make a large impact on flight characteristics, but I wonder why they left this trimming job up to the builder?

As long as it flies ok, no reason to change it now!

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RE: Did I screw up the wing on my avenger? - 7/1/2007 12:11:27 AM

vertical grimmace

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Yes Alex, that is correct. The Avengers did (do?) not come with the wings already the finished shape. I have built and designed many foam wing airplanes for C\L and R\C combat and blocking out the foam is the first steps in the process of cutting an accurate core. This was one of the very disapointing design aspects of the Avenger in my opinion. That is why i choose to fly the Battle axe. Much easier to build.

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RE: Did I screw up the wing on my avenger? - 7/7/2007 3:58:11 PM

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All that matters with the AVENGER, or any combat plane, is that the span, and root and tip chords, are the same. The instructions say to measure the chords and trimto "spec" but this is an unnecessary step. First, make sure the span is the same on both cores, and if not, trim the longest one at the tip to match the shorter one's span. Then, butt-match the root and tip chords (i.e. just hold them together and eyeball the chord match). If they're the same, you're good. If not, mark how much the wider one needs to be trimmed back at either the root, tip, or both, and use a straightedge (an aluminum yard or meter stick works great) and sharp #11 knife to trim the TE to the proper chord. It helps to have a shallow angle between the blade and the foam (i.e. don't have the knife standing straight up) to keep from snagging/gouging the foam. Trust me, you don't have to trim the core chords "to spec", just match them. On 90+% of our AVENGER cores there is no trimming necessary, the occasional one needs touching up a tiny bit. The end results are worth it- it's the best-flying combat plane out there in any class, IMHO.

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RE: Did I screw up the wing on my avenger? - 7/8/2007 8:15:12 PM

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And for my $.02

I trim the TE of the cores I cut to match the aileron stock that I'm using at the time and make sure that the tip and root chords are the same on each wing panel.

Also a single edge razor blade works great for cutting the TE of the cores.

And yes them Avengers are darn good flying planes.

Charles

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RE: Did I screw up the wing on my avenger? - 7/9/2007 1:53:06 AM

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Just get a Battle Axe and don't worry about trimming any cores!

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