Official E-flite 650mm Convergence VTOL Thread

[Twowingtj]

Almost lost mine today as one of the ball links on the pivot arm connected to the motor broke off.....the quality of the connection used here has been less than impressive and very disappointing in fact. The actual shaft for the ball broke off and the push rod went spinning off...leaving no directional control to the motor pivot

Good thing I was only about two feet off the ground when it happened ....or it would have been fatally disastrous!!!

There have been several reports of simular things happening on the other forum. Some folks have replaced the ball links with a different set up with new ball links at both ends. They've had some issues with not having much meat left on the servo arm to support the new balls though. I think a double ended rod with the right size metal clevises would work just as well.

My links are a pretty sloppy fit on the balls. I'd never fly any of my helis with a fit that loose. I haven't been able to fly mine outside yet and may work on a better set up before any transition to forward flight.

[Alpha]

Twowingtj, would you please post a picture of the ball link you guys are discussing?

[xviper]

There have been several reports of simular things happening on the other forum. Some folks have replaced the ball links with a different set up with new ball links at both ends. They've had some issues with not having much meat left on the servo arm to support the new balls though. I think a double ended rod with the right size metal clevises would work just as well.

My links are a pretty sloppy fit on the balls. I'd never fly any of my helis with a fit that loose. I haven't been able to fly mine outside yet and may work on a better set up before any transition to forward flight.

This is true. Of the 3 Convergences at our field, one had very loose ball/ring fitment and slipped off the ball. Another had the ball so tight in the ring that it was very hard to rotate inside. Mine seemed to be in between and has been good. Another thing that has been commented upon is that some of the nacelle covers are screwed on too tight, making the nacelle very stiff and hard to rotate. Loosening the 2 front cover screws alleviated this tremendously. I took mine apart to check the ESC connections and when I screwed them back, I left the front ones just snug.

[Twowingtj]

Twowingtj, would you please post a picture of the ball link you guys are discussing?

Alpha, here is the pic you requested. It's the same on both sides for motor tilt rotation control.

[Brandon Moon]

Twowingtj, would you please post a picture of the ball link you guys are discussing?

Here you go Alpha. As requested. Note the little nut on the back side is where it snapped off and broke....now there is not enough thread to re-secure it. included picture of the opposite side as reference.

[Twowingtj]

One of the challenges with the stock set-up is that the motor control arm is not a standard servo type are. It is unique to this model and fits a square shaft. The servo arm is also non standard. It has 20 splines and is an odd size. Some people have located a fit at bangood.

[Brandon Moon]

Also note: the ball link connector fits very sloppy on the the ball itself....lots of free play

Opened a support ticket (#T417179) at MotionRC for replacement parts

[80gPilot]

I don't have any experience with this Rx. In fact, I can't even find it listed in Horizon Hobby. Do you mean AR9350?

http://www.horizonhobby.com/radios/aircraft-receivers/ar9350-9-channel-as3x-receiver-spmar9350

Have you programmed anything into the Rx yet? I can see a couple things that might prevent this from working.
1. You have put in some programming already and this is interfering with the flight controller. It may not be possible for this Rx to talk to the flight controller because it's already got its own AS3X type of programming. It's like 2 different AS3X systems where one is trying to control the other. (I've tried something like this with the Radian XL. Adding a flight controller to the stock AS3X Rx doesn't work well. One confuses the other. There is a work around but it's not easy.)
2. The Convergence seems to require a long time to initialize (5 to 10 seconds) before you hit the bind button and turn on the TX. Have you allowed enough time for the nacelles to complete their pre-bind cycle? Are they in the vertical position before attempting to bind? This is how you can tell that the FC is ready to try for a bind.
Also, are all the patch cables between the Rx and the FC correct. There should be 6 of them.
Try a simple 6-ch Spektrum Rx like an AR610 and see if this works. If it does, then it's the 9350. If it doesn't, then it could be the cable connections or not waiting long enough for full initialization.

I'm sorry i misled you, the 9503 is my transmitter and the plane is a BindnFly model with the Rx included. I did in fact wait for the nacelles to finish movement to the near upright position before binding transmitter like the manual said to many times?

I did do the programming like the manual said. (i think ). I have not had problems binding before with less complicated BindnFly models? I just wanted to try everything before i take it back to the LHS to see if they can bind it?

[xviper]

I'm sorry i misled you, the 9503 is my transmitter and the plane is a BindnFly model with the Rx included. I did in fact wait for the nacelles to finish movement to the near upright position before binding transmitter like the manual said to many times?

I did do the programming like the manual said. (i think ). I have not had problems binding before with less complicated BindnFly models? I just wanted to try everything before i take it back to the LHS to see if they can bind it?

My bad. I can't seem to find a Spektrum 9503 Tx either. The only reference I see for 9503 is a JR. I'm not sure if JR will work with this plane's Rx. Someone else will have to comment on this.

[80gPilot]

My bad. I can't seem to find a Spektrum 9503 Tx either. The only reference I see for 9503 is a JR. I'm not sure if JR will work with this plane's Rx. Someone else will have to comment on this.

It is a JR radio (not Spektrum) my bad again but it is DMS2?

[xviper]

In "theory", it should work, however, I've read that people have had trouble using the JR on the BNF Convergence. You must remove the stock Rx and get a JR Rx and the 6 cables needed to connect it to the FC.

[80gPilot]

In "theory", it should work, however, I've read that people have had trouble using the JR on the BNF Convergence. You must remove the stock Rx and get a JR Rx and the 6 cables needed to connect it to the FC.

Thx xviper2
kind of a bummer i bought the BindnFly and really got a PlugnPlay! Anybody need a brand new receiver i can't use! What does the rep say on this tread?

[80gPilot]

will see if my LHS will take it back

[xviper]

will see if my LHS will take it back

Yeah, it's too bad you didn't know this beforehand.

[xviper]

I have been continually "tweeking" and making observations of my Convergence in order to dial out some of the undesirable characteristics, listed below.

Definitions: MC = mulitcopter mode; AP = airplane mode; Stability mode = SAFE, limited angles in pitch and roll; Acro mode = limiters removed, no self leveling, AS3X still works to stabilize aircraft from outside influences like wind; FC = flight controller.

a. Lack of reverse capability (ie, "forward creep" hard to negate) in MC, Stability mode.
b. Oscillation when transitioning between MC and AP and back.
c. In AP mode, when going from Stability to acro, plane nose dives and loses altitude quickly, needs a lot of UP elevator to hold level.

I use a DX8-G2. All trims (except for throttle, which is all the way down) are centered.
Switch A is used for Stability and Acro modes.
Switch B is used for MC and AP modes (quickly flipping past the middle position - don't linger in the middle position or it could produce undesirable results).
Switch H is used for throttle cut.
So far, I've flown with 2200mah, 3s, Admiral Pro and the equivalent Turnigy Heavy Duty. The Pro fits the best. Battery is placed as far back as possible. I've run an extension under the battery compartment and out that hole in the front. I've cut a hole in the "firewall" under the windshield to stuff the excess battery cables into.

Servo travel for UP elevator is increased to 150. This addresses the lack or reverse mentioned in (a).
Servo travel for switch B, position 0 is increased to 120. This puts the nacelles to a more level position to make flying in AP mode more efficient.

***Servo rods on the elevons are adjusted to give approx. 2 to 3 degrees of UP elevator when in AP and acro mode. This addresses (c). When in AP mode, going from Stability to acro results in almost no change in the planes pitch attitude. This does NOT affect the way the plane flies in AP/Stability modes or in MC/Stability or acro modes.
***Picture attached. This is approx. Start here and adjust 1/2 turn at a time on the elevon rods till you get zero dip or climb when going to acro in AP mode.
Do this adjustment on the bench, battery connected, throttle cut ON (or props off), in AP mode, acro mode, flat, level surface. Make sure both sides equal.

Some have noted that the angles on the nacelles are different from each other and start messing with the servo rod lengths. They don't necessarily have to be at the same angle and those rods don't necessarily have to be equal length. If you must adjust them, do so for AP/acro mode of flying but doing so could end badly.

The oscillation as described in (b) happens the worst when transitioning between MC and AP modes IF the sticks are moved just prior and during transition. Before throwing the switch from transition in either direction, I find that if it's left in Stability mode for a few seconds and leaving the sticks alone just before and during transition, will reduce or eliminate the oscillation during transition. I think moving the sticks around during this time may be too much input for the FC to handle and might give it a "brain fart". Anyway, by putting it into Stability mode for at least a few seconds before the transition, the oscillation is pretty much gone.

People have noted that this plane flies too quickly and needs a good piece of realestate to fly. This is not true. It can fly very slowly and when banked to the max in AP/Stability mode and using hard rudder inputs, it can turn very tightly. It can almost glide (under low to moderate power) in Stability/AP mode and now that some reflex is mechanically set, it can also fly very slowly in acro/AP mode and the sudden lose of altitude when power is cut in AP mode is greatly reduced and quite manageable. Of note is just how much the CG changes when the engine nacelles go from vertical to horizontal. Look at how much mass is moved forward when those motors and blades rotate. Ideally, they could have made some ballast that could be shifted by a servo when the nacelles rotate or a special bracket made to mount the motors so they don't change CG when rotating. However, it is what it is.

Some folks are constantly trying to trim this plane in both MC and AP modes so they can fly it "hands off". I would suggest not to bother. Messing with the trims on the TX can create conditions that can and has surprised a few pilots. Trimming in Stability mode is quickly forgotten the next time the plane is connected to a battery. Trimming in acro mode is dangerous because going from acro to Stabilized and back to acro when changing flights mode (MC to AP and back) can suddenly upset the plane. Best to leave it alone. I've come to the realization that this craft will NOT fly well "hands off", at least not in MC mode. Let's face it, this is no different than flying a quad or helicopter with NO GPS position hold. It WILL drift to some extent. It WILL creep. You should fly it all the time.
BTW, I believe the forward creep was built into the plane so you at least know which way it's drifting. Most MC and helicopters drift but those can drift in any direction. I think Eflite "dumbed" this thing down and made it creep forward to make it more predictable to some pilots. I think it's a good thing. You don't want to dial that out since then it could drift all over the place.

Also note that reversing in MC/Stability mode is possible but there is a bit of a delay or lag, so plan ahead and expect this. Keep holding the stick back. It WILL come back. In MC/acro mode, backing up is not a problem. In fact, you can do a back flip if you want to.

I am continuing to experiment with this plane to get the most enjoyment out of it and iron out any new oddities that may show up.

[Twowingtj]

xviper2, some good info. I've got mine on a DX9. I've got my transition on switch A, stability to acro on switch B, and throttle cut on H. I had to reverse Aux1. I'm not sure what effect the center position on switch B will have yet. I haven't had a chance to get it outside. Hoping to this Sunday.

I did wind up switching the nacelle linkage to a Trex 500 ball link coupler and rod with a Dubro quick link on the servo arm. I was able to stay with the stock ball as it is 4.7mm, same as Trex. I did remove the original ball, inspected it and reinstalled it. The Trex coupler is much beefier. This set-up has removed all of the slop in the nacelle control system.

[xviper]

xviper2, some good info. I've got mine on a DX9. I've got my transition on switch A, stability to acro on switch B, and throttle cut on H. I had to reverse Aux1. I'm not sure what effect the center position on switch B will have yet. I haven't had a chance to get it outside. Hoping to this Sunday.

I did wind up switching the nacelle linkage to a Trex 500 ball link coupler and rod with a Dubro quick link on the servo arm. I was able to stay with the stock ball as it is 4.7mm, same as Trex. I did remove the original ball, inspected it and reinstalled it. The Trex coupler is much beefier. This set-up has removed all of the slop in the nacelle control system.

I have tried to linger in the middle position on switch B. During transition to AP, this stops the nacelles somewhere in the middle until the switch goes to the outer most position. I don't think this is a good idea as it might cause some conflict in the FC as it's trying to "time" certain events during this phase. I flip past it quickly. Another thing one could do is to program the middle position to have the same input voltage as one of the adjacent positions, thus, making the 3-position switch a 2-position switch.

[Twowingtj]

I have tried to linger in the middle position on switch B. During transition to AP, this stops the nacelles somewhere in the middle until the switch goes to the outer most position. I don't think this is a good idea as it might cause some conflict in the FC as it's trying to "time" certain events during this phase. I flip past it quickly. Another thing one could do is to program the middle position to have the same input voltage as one of the adjacent positions, thus, making the 3-position switch a 2-position switch.

You might have misunderstood. My MR to AP transition is on switch "A" so a two position switch. The reason I did that is because switch "A" is my normal landing gear switch. And since we land and take off in MR mode, it's just a natural switch for me to flip.

Switch "B" is my stability (pos 0) and acro (pos 3) switch. So what I'm not sure of is what happens at pos 2? I might be able to test it in AP mode to see how the control surfaces react to moving the airframe around and hope that the FC will respond the same in MR mode.

[xviper]

You might have misunderstood. My MR to AP transition is on switch "A" so a two position switch. The reason I did that is because switch "A" is my normal landing gear switch. And since we land and take off in MR mode, it's just a natural switch for me to flip.

Switch "B" is my stability (pos 0) and acro (pos 3) switch. So what I'm not sure of is what happens at pos 2? I might be able to test it in AP mode to see how the control surfaces react to moving the airframe around and hope that the FC will respond the same in MR mode.

I get it now. Makes sense to have "A" do that. If you're going to try the middle position for Stability/Acro, I'd do it waaaay up high just in case.

[xviper]

UPDATE: With all the tweaks as mentioned in post #54, I flew the Convergence 3 flights today. I did a right flip, left flip, front somersault, back flip and all worked beautifully. It was just too cold to get a video. Transition MC to AP and back was seamless, as was from Stability to Acro and back. In AP flight, flipping to Acro resulted in zero change in altitude. It stayed level and straight as an arrow. Shutting down the throttle in AP mode in either Stability or Acro resulted in a nice controlled, shallow descending glide, nothing surprising. Powering back up when it got close to the ground was quite predictable. It just went faster, leveled out and easily ascended. Took off from a table top and landed back on the table.