Im starting to get the hang of some 3D manuevers, however, when I try to do a wall with my Extra, the airplane snaps violently to the right. Have any of you guys experienced this? Do you have this and just antisipate and counter with rudder? Is there something set up wrong? CG? Mixing?

Duc

What Extra and setup? To do a Wall, especially with a smaller plane, you need to have a ton of elevator throw and fairly light wing loading. The idea is to pop the airplane up fast enough so it goes through the tip stall range and right into 3D range.

I'll just add a bit more to what Flyflacons already suggested.

Look to make sure the elevators are moving exactly the same amount at exactly the same time and also that lateral balance is right on. Next to what Fly suggested, these are the two most common problems I have run into, especially when the plane is always dropping to the same side.

Knowing what plane and it's setup would definitely help though

Thanks guys, Im flying the TDL Extra 300 / Saito 100 16x3w. Im currently at work so i cant check the throw or how closely they are to moving in unison. They are, however, bothe connected to the same servo, but I understand what you mean about one being a little ahead of the other. I think what Flyfalcons mentioned is whats happening, its stalling before it transits thru to ultra high AOA.

Thanks for your suggestions.
Duc

which livery is your Canadair painted in?

I don't have a model CRJ, though I know there is a small EDF kit out there. That's one of the planes at work that I fly for Delta Connection (Comair).

Thats the one I meant, my dad retired (fired for turning 60) from there in '03 after 14yrs. I couldnt tell if it was ASA or ComAir. I just left XJT after 8 years, tell JC and the boyz Steve Day said hey.

Steve

Its also possible you are giving some right aileron,I have trouble with that,I started using a neck strap so I can hold the Xmitter steadier. What size and weight is the plane?

How much elevator throw do you have and where's the CG? Not enough throw with a forward CG will certainly cause a snap; especially at relatively high speed. Make sure you've got at least 35 degrees of throw. Can you give a real brief explanation as to how you are executing the manuever?

OMG Steve! Have you already forgotton basic side-slip aerodynamics?

Since we don't have turn-coordinators on our RCs it becomes a little more difficult, but basically what is happing is the same thing when you do an uncoordinated stall in a C152 - we drop a wing.

Your plane is just slightly yawing to the right. That does seem odd because of the torque of the engine pulling you left. Now that I think of it, do you have any right thrust built in?

The best way that I know how to check to see if the "ball" is centered is to fly straight up. Of course, your rudder is almost too farkin huge. One click to the left or right might take it out of trim. You might have to go into your sub-trims.


As far as "handle" changes, I might start using my flightinfo and expressjetpilots one: Capt. Caucasian. (inside joke yall)

Jungle Jet Joel,

You found me, BTW, the 75/76 TC is just like the 145. But yea the firewall has thrust built in, I moved the CG back like the ComAir guy (FlyFalcon) suggested and I increased the throw on the elevators (AHPwellson). Hoped to get to fly today but had tree trimming to do (Hurricane Prep). Ill be out there tomorrow hoping to get this thing dialed in. The girls have their B-day party so I have to wait till thats all finished. Where are the picsof the smacked up Bipe?

Later,
Steve

Steve,

For a wall, you have to "break through" the stall into the realm of "induced lift" aka high alpa. So, the maneuver has to be reletively quick. Also, power is key. Just as you are passing the point of the stall you have to add in power. Too little power and the stall will escalate and it may snap. Too much power and one of two things can happen: it will keep climbing, or it will snap in the direction of the torque, P-factor, accelerated slipstream, and gyroscopic procession (or is it pre-cession?). You know, to the left. Clear as mud? Basically you just do it, stop thinking.

I tried to post some pics but RCU says there is an error while saving. Take a look in my gallery, they are there.

All that sounds too complicated,I just slow down to a low throttle setting,leave about one click or two on for high idle,coast for a while to bleed off most of the speed,then,pull and hold full up until the nose is almost verticle,then let go of elevator to start a hover,or what ever. I dont let the plane fully stall,specially since I do walls just off the ground sometimes to start a very low hover.
I've even smacked the tail wheel into the ground while rotating,I use a lot of spoileron mix with the Do so it looks like a wall to me,though after reading these highly technical descriptions, I,m not so sure I'm doing a proper wall,but hey,it works for me!

I was just making all that earlier stuff up

Thought so,you lost me with the P-factor & accelerated slip-stream,gyroscopic mumbo jumbo,like you said,just do it. Get to safe height,flying level,cut throttle,coast to just about stall,pull & hold full up-see what happens & take it from there.

I usually hit the throttle with elevator and then back off power to keep it from climbing Its like an exaggerated blip.

All the above plus check your lateral balance........
If you have right thrust you will have to get into the rudder some to stay level.
Some planes do straight up, some don't, airspeed has a lot to do with it also.

Hi guys....................I had exactly the same problem in my Funtana 90, an Up Roar and OMP Katana 46. The problem here is lateral balance.
All planes with side engine the right side is heavier than the left....so when you pull hard the plane has this tendency to right snap.
When balancing your plane don't use the engine shaft to hang the plane.....this is not the geometrical axis as it normally has a right thrust angle. You need to find the exact long. axis and then use it to balance the plane.

Marcos

Thanks to all who have contributed, except of course ALPAPILOT, who can trust ALPA? theyre just a bunch of thugs (side joke between two former reps). I have moved the CG back...WAAAAYYY back, and added a little spoileron mix, and it has greatly reduced the snap. However, what Marcos suggested, might be the final puzzle piece. The Saito is mounted on its side, How do I go about balancing it the way you suggest?

Duc

Carefully measure the fuselage and find the middle point at landing gear or firewall. Place a pivot at this point and hold the plane at the fin so it will be level. See how much weight is needed to laterally balance your plane(try not to force the plane to either side while holding it at the fin). It is an easy job............probably will need some help to hold the plane in place during process.
Before balancing my Funtana this way it snap badly every time I pull hard on ele.
Hope this help......

Marcos

Elevator throw needs to be equal, and lateral balance needs to be perfect.

Well lateral balance needs to be close, mine isnt perfect and none of my planes have wanted to snap provided the following.
The elevators are setup with perfectly equal throws and they get there at the same time. If you have dual elevator servos and one has more deflection that than the other you will snap out of a wall OR
One elevator gets there faster than the other. Sometimes setups are such that the elevators end up in the same place but one gets there faster than the other. You control linkage geometry needs to be identical on both sides. I dont think that slight variations in servo speed matter enough to make as big of a differnce as setup does. OR
A weaker servo on one side than the other. Both servos have to hold equally under the stress of the maneuver. Regardless of what your servos do under a static load sitting on the table, if one of them gives in to the pushback during the force of a wall, your throws are not equal and the effect is the same as if your throws arent matched on the table. OR
The plane is too heavy, if the plane tends to snap at unwanted times during normal flight or when landing, its certainly going to want to snap in a wall. The plane needs to have a low wingload.

Thanks to all the suggestions, I've been working alot and havent had a chance to try Marcos lateral balance technique. As far as elevator servos, there is only one and the geometry, as far as I can tell is the same. This is a great resource, with global participation.


Duc