4 things prevent flutter.
1) strong servos
2) strong hardware
3) strong airframe
4) speed
Thats it; no balancing; no calculations and no slide ruler.
Do you mean that all of the 35% and 40% planes Ive flown had balanced ailerons.
I don't think so.
So balance those ailerons, I'll be out flying
Who cares about full scale.

T. Bob,

Aerodynamics is aerodynamics is aerodynamics, is aerodynamics. There is NOT a different set of rules for full-scale and small-scale.

There are old pilots; there are bold pilots; there are no............

With condolences,

C. Earnest

:-)

pceagon I have to agree with Charles on this one. I have the latest model D.P. 330L and only have one servo on each aileron I have a moki 1.80 for power and never fly the plane over 1/2 throttle except on up lines so far never a hint of flutter even Dave Patrick says fly it slow to prevent flutter so in my opinion speed is the culprit

silly question,
but how do mass balance the ailerons? i m thinking about doing for H9 extra #2 with 1 servo setup.

D-Bird,

Do you remember the website or post that covered mass balancing? I don't at the moment.

Ronbo:
There is a multitude of info on aerodynamic flutter causes and effects available. Just do a web-ferret or google search on it and you'll find lots. It makes for very interesting reading, and a must for taking part in discussions on the subject.

Charles Earnest

i am running one 8411 on 6 volts on mine whats size is the 2 servo option says to use maybe 2 standard hum!!!!!

Balancing full scale ailerons is for the ease and the comfort of the pilot.
But on a RC plane with digital servos at 180 oz. + it's just a waste of weight and time.
At all of the IMAC events I've been to I have never herd a pilot say "Boy; I really need to balance my ailerons."

the things that make you say HUM

looking for the 'how to' to mass balance our ailerons, such as was posted for the cap 232 mentioned with the fishing wieght.. what im looking for, how to get it right etc.

i have seen aileron balanced at an imac meet with the extentions at the tips... but i didnt inquire how or why.... was on a 1/4 scale or just slightly bigger Edge.

Flutter is a function of speed and is soley dependent upon speed for the energy required to induce the violent oscillations know as flutter...

The two common sources of flutter for models are bending moments and torsional stiffness. Both are realized of various design parameters of our model airplanes, IMO. The results and remedies are identical but these are two unique events...

All aircraft have a known theoretical FLUTTER SPEED. Never exceeding the aileron flutter speed in of itself will prevent flutter from every occurring. I suppose the problem we as modelers have is understanding, realizing and flying below the flutter speed, unfortunately the designers don't offer this info and more than likely do not even know what speed flutter occurs at with their models.

In a nutshell inertia realized from the wing bending or twisting and unloading causes the ailerons to overshoot there intended positions. The twisting/bending/overshooting becomes a perpetual motion to destruction or not. This happens simply because the CG is behind the hinge centerline and the linkages are inherently slightly flexible within their travel arc...

Building stiffer stronger wings and ailerons will do nothing other than increase the models aileron flutter speed or vne.

Mass balancing ailerons eliminates the ability of the aileron to overshoot it's intended position. Thus inertia is not present with CG directly on the hinge centerline and it cannot induce the aileron to overshoot its intended positions held by the control linkages/servos and aileron flutter is no more... There are other types of flutter as well such as wing flutter and tail feather flutter. The latter is dealt with and realized for the same reasoning as above.

Most likely reasoning for this is the surfaces are substantially stronger than others... Yes having high power servos helps dampen the flutter event it does not eliminate it. It still exists its just a matter of speed.

Mass balancing removes the ability for flutter to perform its destructive dance...

MGlavin,

Thanks. I've been saying the same things, in different ways, for weeks. Positive feedback of lagging control surfaces or trailing edges through either flex or torsion. Best cure: stop the process from starting. Inherent structural strength or mass balancing. Someone should do a mpeg, or some-such, pictoral representation.

D-Bird; now there are three (or more)................

Charles Earnest

I never "herd" anyone say that either.

I balanced a H9 extras ailerons and flew it with just one servo/aileron. Twice I lost the gears in one of the servos and was able to land the airplane with no flutter. Without gears in the servo the aileron was completely free. It was not a waste of time for me.
I lost the gears due to other problems- not flutter.

There are several ways to balance the ailerons . One is shown in the latest RCM in the how to do it column. It combines the balancing system with the control horn.

BTW balancing the surfaces would surely ease and comfort the pilot. I bet he would surely be uncomfortable knowing they were not. I would not go near an airplane that didn't have it.

Where is that how to do it column?

Interesting discussion about flutter both those for and those against.

When I attended the TOC in 1998 I was particularly interested to note that most of the planes in attendance had some form of static balance/ counter blaance. Most achieved this on the tips with a weight forward of the hinge line running along the tip. Some had ball weights on arms extending past the hinge line. It taught me a lesson in that if its good enough for the elite of our sport/hobby then its good enough for those who aspire to be the same.

On reading the varous discussions in this thread I havent once seen anyone suffering from flutter when the ailerons are balanced and I've never heard of it around the traps when flying.

Its in RCM's readers input column. I thought it was called "How to do it". I don't have the mag here. But its the column where the readers send in their tips and its usually published with a little sketch.

I just looked it up. Its pg 96 in RCM. The "What its Worth" column

BTW the column calls it dynamic balance. That is incorrect. Its static balance.

T. Bob,

Will you please explain to me how mass-balancing control surfaces eases the pilot's job, except for a light aircraft maybe, where the pilot's pre-flight involves manually moving control surfaces to check for mechanical problems? In-flight surface pressure is aerodynamically induced and unless surfaces are hydraulically or "boost-tab" aided is just "me against the air". This, (and flutter) is what causes stripped servo gears. To my knowledge, mass-balancing is "static" in relation to control surface pressure, unless at 0 mph airspeed. If you move an elevator (on the ground)and it stays where you put it, it is balanced. Same for ailerons when they are disconnected from the control system. Unless there is a post to me personally to which I have to reply this will be my last in this string. It has been a great discussion and I have enjoyed it immensely :-)

Regards to all my friends, Charles Earnest

Thanks dirtybird. I misinterperated and thought you meant it was a section here on RCU. I don't subscribe to RCM anymore. I cut back to just one magazine and I dropped RCM.

Hey Guys,
All I got to say is I've been flying mine for 2years now and had NO Flutter ever!!!! This is the second run kit I have..Maybe its because I'm only using a os160.. The new design has provisions for dual servos and other things for the bigger gas jobs.. Maybe it has something to do with the vibes the bigger motors put out...
Well anyway I think DP's planes rock!!
Good Luck with your flutter fixin.
Frank

I agree, I have first gen DP extra, had a moki 1.8 on it for a long time, now I put a Brison 3.2, one servo per aileron, and no flutter problems. This is a FUN plane!

i feel u all
brison 3.2
8411 on the rudder and ailerons
no flutter here just one sweet flying extra

johnvh,
How was it with the Moki1.8 on it?
I got my Moki in my Cap 10 and it rips it around!!! I need to fix the Cap10 and was thinking about putting it in the Extra..
Did ya use the DP mount or the radial Moki mount?
Do I need to put the servos back in the tail? I have the pull-pull set up on it know..
Thanks
Frank

Here is a pic of it on the DP.


It flew around good, but vertical was pretty lacking, thats why I went with the big gasser on it. It had just enough to hover, but pull out was terrible. The Schimitar 19x8 was the best prop I had on it.

gas and more gas

Looks exactly like mine