I know what Neutral point is... its the Point at which all Aerodynamic forces are equal And If you want me too, I can get out my Airframe Book from school and give you the Equation for it if you really want me too... I will be the bigger man here and admit I did misread your post and I Apoligize for that. With saying this My Statment is still correct... I was trying to help the guy with his problem, he stated that his CG is centered, If he says it is centered then why are talking about it ??? a Tail-Heavy CG would still not cause a plane to Favor one wing, if it does it would cause the left wing to dip not the right!, That is the whole point I am trying to get across, I do not wish to argue anymore, so I think I will take my ball and go home!

Welllll............... actually what da Rock was trying to say was that it's normal for tapered wing models like the OP was asking about to snap very easy naturally and especially if the elevator had too much throw. It's quite normal for this forum to have relatively new modelers to our hobby wind up here wondering what's "wrong" with an Edge, Cap, Yak, Sukhoi, etc they just finished. It's usually the first tapered wing, non-trainer type they've flown. They're usually very sure the behavior that surprised them shouldn't be happening. And I must admit to feeling that the opening post was a repeat of that situation.

Sorry that I didn't use lots more words to qualify my response within that first sentence. I planned to lay it all out in the sentences that followed, but must not have.

But I will stand by my guarantee.
I have always guaranteed that if you're not entirely satisfied, there will be no additional charge.

The right hand snap is fairly normal
Why?
The single biggest reason is that the mode 2 flyer ,typically adds right aileron as they add elevator
This becomes automatic -and if the UP is pulled hard -the condition is exacerbated.
Don't believe it ?
I don't care .

"Don't believe it ?
I don't care . "

I bow to superior logic.
With that 'ditty' you've established a new superlative.

Re-read the original post please.

The poor guy quite plainly said that it's also breaking to the right during stalls. He didn't spec what type of stall, but it does narrow the problem down all the same to something NOT "normal". That was his question, whether this was "normal".

And rather than finding an answer to the man's question, I've read several posters re-defining the question to fit their apparently favorite canned answer. To wit: "You are stupid, we are smart. You are a newb with bad thumbs, we are vastly more experienced (167 years!!) and have golden thumbs. You should quake before the very might of our published experience and be grateful for the wisdom of our brow-beating. If you didn't SUCK, then the airplane would be flying just fine"

U think I'm off base in that analysis? Perhaps I am. But if you carefully re-read what is actually written above, one post at a time, then perhaps you could forgive my mis-interpretation.

I guess for some ,this sounds harsh
But Imeant what I said - and to es'plain to those who misunderstood me -
I simply meant that it is a fact.
It is a fact that what we unconsciously do when flying , does NOT register as an error on our part
The tendenceny to pull right with up is as common as fleas on a dog.- We
"learn it"
Why?
one, it tends to overcome any prop forces which pull to the left AND cause some rotation at the sam time -and so we imprint that correction and do it automatically.
Two, unless one has a really good tray setup, a pure elevator input takes some careful hand training.
A thumbs only flyer has a better chance of moving the stick in a straight line
Anyone can learn to do it but the natural hand movement -using thumb and forefinger is to pull toward the palm.
accomplished musicaians on strings/woodwinds etc., ran into the same thing- learing to make unnatural finger movements .
Dave Brown -who was a past president of AMA- flew holding in a tiny bit of up elevator so that down lines and inverted sections of maneuvers required less "correction."
I tried it -but it did not work for me.
Neither does Mode 1
Actually, mode 4 (ail and throttle on the left)works for me -but not as well as mode 2.


Learned responses are both good and bad.

I've got a .40 size Giles 202 that will snap to the right when you pull full up elevator. Is this normal. I've been told that they are designed to do that.

You can ignore further helpful info of that type-

kq, any model that has a highly tapered wing with a high enough wingloading will be prone to that when least expected or at the worst times...all the first planes I ever designed were very good at snapping until I finally got a clue.
If the wingloading is right, the tendency is dampered, even eliminated. My goal for a good handling model is to be able to use the elevator at will to make the model go up and down, not to make it stall to one side or the other. A good model in my opinion needs both rudder and elevator commanded to generate a snap at flying speeds.
Some "built in" tendencies that full scale planes have don't scale down very well or lend themselves well to good handling models.
There are a lot of great examples of 3D models of the full scale aerobats that have bumped the wing area way up past "scale" and are more forgiving than your average trainer. These planes will fly circles around their more scale like counterparts and avoid involvement in those messy garbage bag rituals better, too.

Thanks Combat,
 The wingspan on this Giles is 49.5 and the wing loading is to the higher side. When test flying the model I almost lost it twice due to this snap at low altitude. I did not know that would occur. I have learned to not get into a situation that calls for full elevator.

pigg hit on the stuff dick Hanson has been preaching for a long time. Wing loading, wing loading, wing loading. The heavier the wing loading the nastier the snap tendency.

Ok, light is always better, the lightest model is the best.

However, what do you believe is a god compromise for regular mortals, like Santiagotor (OP) and kq4ra, who own a heavy model, and still want to have some fun with them instead of trying to sell them out or permanently hang them from a room ceiling?

Is the old CL trick of mixing elevator with flaps or flaperons a crazy idea that may help to palliate nasty snaps that are persistent in these RC models?[sm=idea.gif]

Probably with such a big motor on the plane, it is trimmed to the left to stay level, and when the power is pulled back or it looses airspeed, the trim balance is gone. Latency in the radio mixes can be a problem too

I'm ok with the plane as long as I know what to expect. It's the surprises that catch you off guard.

It works like gangbusters in C/L but there's a difference and a caveat.

Coupled flaps are going to work safer than using coupled ailerons as flaperons. The flaperons can be a help, but aren't as safe a choice. There's also a good bet they'll have just as nasty a snap when you push the plane too hard. Since there is a tried and true proceedure already, why not try that first. Learn to fly the plane the way it needs to be flown. And consider trimming the amount of elevator deflection if that seems necessary.

The biggest problem we have with this edge/sukhoi/etc "suddenly snapping for no reason" problem is education. Way too many modelers have noone around them who know to warn them that a tapered wing aerobatic plane needs to be flown with the consideration tapered wing aerobatic planes need.

Copied from:

http://www.quicktechhobby.com/articl...lle_part_2.htm

"The Wall
What it is: The Wall is a Parachute turned on end. The model starts in normal level flight and suddenly corners nose up 90º...as if it hit a wall.
Setup: A 3D setup is a must, i.e. 40° elevator, and be sure to use Expo. Flip the switch to turn on the spoilerons. This will help to keep the Extra from teetering back and forth. Setting the CG toward the aft location will help, but I have had great results even at the forward CG location.
How to do it: Start from about 100 feet straight and level, chop throttle, and as the model begins to slow down, quickly pull full up elevator. When the plane corners to vertical, add full power and release the up elevator. (Tip: Start a low speed and add power at the same time that you begin to pull full up elevator).
Recovery: Simply release the elevator, go to full throttle, and fly out upward.
Advanced Recovery: Juggle the throttle to sustain a hover and transition into a Torque Roll.
Worst way to mess up: If you don't get the throttle in quickly enough, the model falls backward. Not good."

Thanks, da Rock; you have made me think about the flaw of using flaperons.

That is an idea I have been contemplating for RC, since it works so good to tighten corners in CL.

This might sound like a Yogi Berra-ism, but coupled flaps work best on planes that don't need them. For a model that displayed the snap bad enough to make me not want to fly it, or to make me be sure to always bring a Hefty bag out to the field....a couple things could be done.
First, build a wing with less radical tapers and sneak in some extra wing area.
Second, get rid of all hardware and onboard equipment that is heavier than it needs to be. Anyone with a militant attitude and some money to spend on downsized gear can find ways to dump weight.
This is the side of the hobby that can be fun and interesting if you are up to it.

"First, build a wing with less radical tapers and sneak in some extra wing area."

Exactly my plan for an upcoming Sukhoi 29 ARC build. Already have the cores for a new wing, still tapered but with wider tips, which will considerably increase the wing area. It will be extra work and expense but in the long run will result in a better flying plane. I have some planform pictures of full scale Sukhois that show some pretty wide tipped, stubby looking wings. Unlike the wings on some (especially this one) models of Sukhois.

Terry in LP

You mention the, "pretty wide tipped, stubby looking wings".

Longer span slows the roll rate. Look at all the hershey bar wing models like the Tiger series. They've got all that span for a couple of reasons. The easiest way to get them a quicker roll rate and at least a chance of being able to snap is to cut the span a bay or two each side.

So the model you mention got the "pretty wide tips" to slow the snapping tendency and the "stubby" is there to keep the roll rate high.

One of my planes that I referred to earlier that was snappy was a Sukhoi. Again, I don't want to mention any brands because my purpose is not to bad mouth any manufacturer but rather to bring light to the fact there are some brands that are better than others when it comes to snappiness. (actually I should say "they don't" snap instead of they are "better") The Sukhoi was helped tremendously by rigging the ailerons with the trailing edge about 1/8" to 3/16" up when they were neutral. It was still snappy but not nearly as bad. The first 50cc plane I bought that had NO snappiness was a Comp-ARF Extra 330 that was used which I got at a swap-meet for a 100 bucks. It was more of an IMAC plane but it would do some 3D stuff fairly well. Shortly thereafter I had the opportunity to fly my nephew's AeroWorks Extra 260 50cc and was so impressed that I sold the Comp-ARF and got the AeroWorks. I've never regretted that move.

One last note - I also have an EFlite Extra that has NO snappiness and it's tiny compared to the AeroWorks Extras so size isn't it. It also has tapered wings so that ain't it either. The CG on it is so far back the plane climbs pretty bad when rolled inverted from level flight. I haven't done the math but the CG on it is probably behind the neutral point and that thing is a blast to fly.

When I said "full scale" I meant people totin' size.

Jezmo, likely that Eflite Extra enjoys a very light wing loading for that size wingspan. A light loading is a sure guarantee that you'll reduce any snap rolling problems.

So long as we have Bruce's attention.........
Would you please comment on "flight" (I use the word loosely) on any plane with the CG located behind (that doesn't mean .001") the neutral point !

My remarks on this are included in post #15.............and I'm still impressed !!!!!!!!

you can get back up all you want but I know other people on this forum that can Back up my comments, A plane can fly with a CG past the Neutral point I have done it, I know other people that have done it, with the right Airframe it actually does not fly bad at all,