To have counter balances or not!!!

[andywynn]

Hi Guys, Do you really need elevator counter balances to perform advanced 3D aerobatics? I notice that the majority of 3D planes do have them, does it make them more effective? I am currently building the Aerotech 42% Extra 300, it doesn't have counter balances but it says it will 3D very well, if it makes a difference i can build them in now as i am building it.
It would be great to hear the thoughts of the masses !!

Cheers

Andy

[SmoothFlying]

If the plans dont call for it dont put them in. You'll be fine. Build like the plans say and it will 3D well. Dont know but it could completely change the whole flying characteristics.

[3ddd]

i think they are mainly to help reduce servo load in full deflections,don't think it really helps with airflow over the control surfaces as twords more authority

[brownj]

Gents,
Doesn't the full scale E300 have counter-balanced elevators?
If so, I'm not sure why the AT model doesn't have them?
The E260 (and 230) didn't have counter-balanced elevators, but the successors did I believe.
FWIW, if you chose to use counter-balanced elevators, you can further reduce the elevator servo workload by 'balancing' the elevators. Simply add some weight to the lead edge of the counter-balance part of the elevator: a small hole drilled from the fuselage side of the counter balance does the trick. The weights I have heard vary from 1 to 1.75 ozs. I have 1.5 ozs in my MX2. They don't need to balance perfectly (elevator at neutral), but the weight should allow the elevator to move much easier by hand, and not drop to the absolute down (or up) position.

[bzrogers]

I recently went through this same debate with several people. Here is what I learned.

The full scale Extra 300 did not have counterbalances.
The reason a lot of models have counter balances is to assist the servo. However modern servos have enough power that this is no longer needed.
No counter balance is less likely to flutter than one with a counterbalance.

Personally I like the look of not haveing a counter balance and that is what I am doing with my 300.

Just be sure to get a good link aka mechanical advantage with your servo vs the elevator and you will be able to 3D or fly Precision just fine.

Cheers
BZR

[andywynn]

Thanks for the comments guys, i think i'll leave it with out the counter balances, just put 2 Hi-tech 5955's per elevator and make sure i get 55 deg's of travel each way. i was going to use 3mm rods to connect them up is this man enough for the job or should i go to 4mm.

[Gus155]

	Quote: Originally Posted by andywynn
	Thanks for the comments guys, i think i'll leave it with out the counter balances, just put 2 Hi-tech 5955's per elevator and make sure i get 55 deg's of travel each way. i was going to use 3mm rods to connect them up is this man enough for the job or should i go to 4mm.

hangar 9 titanium links are cool. if not i would use 4mm. 3mm is a bit light for a 42%er

[thewrap]

No you don't. I know that some of the Edges and 260's fly with out them.

[BuzzBoy]

Gee, I wonder why there called counterbalancers? Could this actually be a full scale term that is applied for static balance of a control surface? Counterbalancers serve no purpose on our applications except appearance. Build 2 planes idenicle, one with and one without and you'll never tell a difference, 3D or precision. With that said an Extra would look funny without a counterbalancer on the rudder. Carden 330's usta have um, 260's and 300's don't. A Yak just wouldn't look correct without them even though it would fly just fine without..

[FlyinTiger]

I had two sets of elevators for my Columbo Andersen E300. I flew precision with the NON-counterbalanced elevators, they were less sensitive at the same throws as the counterbalanced ones.

With counterbalances part of the elevator is like a full-flying stab, very effective.

My 3D stabs were amazingly more effective than the non-counterbalanced precision stabs. I can't explain it better than that, and experience doesn't lie.

Now, if you have large enough control surfaces, then you won't have any problem pitching that plane with authority.

Good luck!

[bob_nj]

A buddy at the field the other day tore the counterbalance off of his elevator while messin aroundon the deck. It was an open framwork structure, so no big deal. He just turned around and landed for the day.They're a hazard in this instance!

[KrisW]

If you want really good aerodynamic effect, you ditch aerobalancers and go to full-flying stabilators. Aerobalancers look . . "cool" . . but their actual aerodynamic effect, especialy in low-speed flight, is pretty small, unless they are so oversized as to look ridiculous.

They are almost zero help in IMAC and Pattern, since the focus is on smoothness, not sudden movement. You sure don't need them to 3D, either. QQ proved that at the TOC 7-8 years ago.

In answering the questions concerning the Extra series planes and aerobalancers .

230. . no
260. . no
300 midwing. . no
200. . no
300l. . no till 7-8 years ago. . Optional now.
300s. . no till 7-8 years ago. Optional now.
300LP can be bought with or without them.

You'd have to check with Extra Aircraft about refitting the plane with the bigger tail and modified horizontal pieces, but I'm sure just about any of the 300 series planes can be refitted with the pieces, since the entire tail is bolt on, and the plane could be re-rigged for the newer parts. Patty's 300s has the 10% larger fin, but standard horizontal pieces (no balancing) if anyone is interested.

As for COUNTER balancing. . the Extra's with aerobalanced elevators actually have a small weighted counter balance arm inside the fuselage. Both the Aerobalancers and weighted counterbalancing are done because the chord of the elevator is longer which increased the inertia and stiffened the flying characteristics of the panels, necessitating more weight to static balance the weight of the elevator, as well as a bit of aerodynamic boost from the aerobalancers.

Every plane is designed, in full scale applications, to minimize flutter tendencies and reduce control input pressures so that they are easier to fly. There's a reason certain planes have aerodynamic aerobalancers, spades, recessed hinge lines, and static balanced surfaces, and others do not. Our models, with strong servos, make these things less necessary.

[brownj]

Well said Kris, and thanks for the research.

[jerry ream]

Has anyone with a 40% Carden Extra 300 midwing had any flutter issues with elevators with unbalanced counter balancers. Or have you had servo failure that caused elevator flutter on this plane. Thanks!!! Jerry

[3D-Seth]

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