Originally Posted by RHough

I have a bit of a brain teaser for the tuners.

There is some coupling of controls in the tandem. I'm a bit fussy about making any mechanical trim adjustments I can so the TX trims are as close to center as possible.

Here is what the Heli does:
Right gives Right + Back
Left gives Left + Foreward

Right Piros = gain in altitude
Left Piros = loss of altitude

Very slight Left drift
...
..
Anyone thought this out? I think I've read every post in the tandem threads and I haven't seen a tuning/troubleshooting guide. Is there any interest?

R

LOL I just figured that's the way tandems fly and adjust when controling it. Left drift can be simply trimmed out. I've noticed as it collects wear and tear the flight trim changes a bit. My rear lower rotor gear (outside shaft) has a nice sticky spot or two.

Originally Posted by Grejen

LOL I just figured that's the way tandems fly and adjust when controling it. Left drift can be simply trimmed out. I've noticed as it collects wear and tear the flight trim changes a bit. My rear lower rotor gear (outside shaft) has a nice sticky spot or two.

I have to laugh too. The darn thing is so light that it reacts to the dog farting.

For what its worth:

Forward Rotor Swash Adjustments:
Turns out (longer control rod) = Left Roll
Turns in (shorter control rod) = Right Roll

Aft Rotor Swash Adjustments:
Turns out (longer control rod) = Right Roll
Turns in (shorter control rod) = Left Roll

R

You dont have adjust the servo rods on the front or aft...just pop the one on the 5n1 and turn it either way.

Originally Posted by Jake8131

You dont have adjust the servo rods on the front or aft...just pop the one on the 5n1 and turn it either way.

That works to correct a left/right drift (roll). To correct for a roll induced yaw, you have to adjust the front/rear links.

If you have to put left or right (roll) trim in and no rudder (yaw) trim, adjusting the center link works.

If you have just rudder trim or both rudder and roll trim on the tx, you can trim it out using the front and back links.

The two rotors interact and finding the settings that require the least tx trim makes the heli fly much better. I'm getting very close to no drift and no yaw with equal speed piros both directions with no altitude change.

I haven't figured out how to get the gyro to get happy without a short flight, land, reset and fly routine. Once it is warmed up and happy it is very stable. There is some change in yaw trim required as the voltage changes during a flight this seems to be "normal".

I've gone from having to add both rudder (yaw) and aileron (roll) trim to near center hands off hover. Once that's dialed a click or two of forward or aft trim will make it perfect.

R

Share you settings, please.

Jake - Those settings/adjustments are probably unique to the particular airframe. Something you have to 'play' with. If the body could be removed without pulling rotors and lighting wires I'd probably do a lot more fiddling with it.

R - My CX seems to have a similar yaw gyro issue. Towards the end of the flight (I don't overwork my batteries) it seems to need tons or CW yaw trim then next time I fly it I have to take it all back out.

I've got mine pretty good now...just a little forward drift, but right yaw doesn't kick itself in till about 4mins into the flight which I am about done with it.

Just wondering, how does one change the inner shaft that holds the stabilizer bar? Does the plastic body have to come off? Is it a hard job?

thanks!

Small fingers. Remove the lower gear and the inner shaft will pull right out.

Originally Posted by Jake8131

Small fingers. Remove the lower gear and the inner shaft will pull right out.

I see it now, there is NO way my big meat-hooks are getting that out. Going to put some cut's in the back of the fuselage cover so I can just fold it down..

update: that did the trick & lesson learned - keep college aged boys away from my toys, I have two of them and within a day both my Night Vapor and Heli were grounded!

Try swapping out the 5n1!!!! Real fun!

Originally Posted by Grejen

LOL I just figured that's the way tandems fly and adjust when controling it. Left drift can be simply trimmed out. I've noticed as it collects wear and tear the flight trim changes a bit. My rear lower rotor gear (outside shaft) has a nice sticky spot or two.

Well ... after spending some time waiting for a new swash plate to replace the one I broke making adjustments ...

Yep ... some of it is just the way it flies.

I took the body off and made sure the frame was straight and the rotor shafts are parallel.

Then I made sure that with the Tx trims centered that both swash plates were level (90 deg to the rotor shafts).

There is just a bit of fore - aft movement when left/right cyclic is applied but no continuous fore - aft after sideways flight is established ... so much for all my "tuning" ...

I'm left with a tiny drift that should be adjustable at the servo link (as Jake suggested) and a slightly faster left piro than right.

Next up is a mount for a 500 mAh battery ... the 120SR uses a single cell 500 mAh battery and comes with a harness that plugs into the board ...

12 min+ flight time!

The 500 mAh battery weighs only 50% more than the 250 mAh that is stock ... so double the capacity for a small weight gain.

I wish there was enough demand for this heli for Blade to use some of the upgraded programming and bits from the mCX2 ... the throttle and gyro on the mCX2 are so much better ... if the mCX2 upper swash was a separate part you could have the "high rate" option on the tandem ...

Does anyone know a cure for the gyro? Fly for 30 - 40 seconds, while fighting the yaw. Land, reset the gyro, and it is just fine for the rest of the flight. I'm concluding that it is just the nature of the beast.

R

I bought one of these and love it aside from all the obvious previous listed issues. My dad got one and noticed the rear motor controlling the lower blades was bad. It would not turn. If you gave it a spin it would work but did not have enough power to fly. When you cut throttle it would not spin again.

I took a used motor from a Blade mCX and extended the wires and tried that. The motor worked visibly as you think it should but the heli would spin hard left and crash backwards. I am thinking there may be some importance in the uniformity of front and rear motor capacity/performance, correct? If the rear motor is used and not creating as much lift as the front...crash!!! He called HH who is sending a new motor but has yet to install it. What do you think, bad motor causing issues or possibly something bigger?

I recently bought a new RTF Tandem Rescue and thought I'd pass on the great price to our UK members - http://www.danielstores.co.uk/p/7666...cro-helicopter - the store was great to deal with and I'd happily buy from them again.

When I bought the Tandem I also bought a DX6i (also a good price) and they threw in a spare battery for the Tandem for free...

Just wanted to say thinks for this great thread. I bought one of these as my first RC Helicopter a few weeks ago on an impulse buy as the sale price was great at my LHS. I've been flying RC planes for a number of years and have stayed away from helicopters.

After a pretty frustrating initial flights (little control, turned left, impossible to hover, etc) I read through this entire thread and tried the twist solution (didn't work), then I found the recommendation to re-center the trims and rebind to the helicopter. It is now a pretty decent flier, hover still requires significant right stick back input, and right turns are not bad, left turns are fast. I've noticed that abrupt control inputs causes extremely quick lose of attitude.

So like planes, smooth combined controlled inputs are key.