TDR Technical Stuff (Tips) & Build Videos

[aussiemick]

You may have levelled the swash while not in setup mode in the VBar software???

If you turn the heli on and don't move the heli it will look for all intents and purpose like it was in setup mode. I managed to do it that way the first time I went and put the pitch gauge on the heli, wondered why it kept changing, and this is my fourth VBar heli!

Mick

[nyc863]

I don't think so, since I was adjusting the swash using the 4 way buttons on the screen. That is what I mean by levelling - not mechanically, was doing it in v-bar.
And you can't do that without being in setup mode!

which is the confusing thing.. I have a very distinct memory of using the white plastic gadget to carefully level the middle, bottom and top in software ,and seeing the servo arms at a mis-matched position at the end. Mechanically it was fine and I didn't need to adjust the link lengths as the trim in the v-bar required was very small.

I flew again today, and with the proper flat swash and everything feels right now, except the bounce in the tail, which I am thinking is probably a bad tail servo choice on my part

Have normal set to silly low head speed and a "gentle" bank, and idle-1 set to 1750, and idle-2 set to 1850 and the most aggressive bank. wow it sure does make a lot of mechanical/metal type meshing noises vs the logos!

[aussiemick]

Originally Posted by nyc863

Wow it sure does make a lot of mechanical/metal type meshing noises vs the logos!

Really??
Mine is quieter than the Logo 600 on 10S that gets flown at our club, apart from blade noise it is quieter than my TRex500.
The only time gear noise can be heard at all is when the disk gets unloaded during fast descents, and then only for half a second or so.

Mick

[nyc863]

Hm, well, after I've gone over the heli I might try to make a recording of a hover.

Definitely more noisy than my logo. But the logo has only one gear mesh - pinion to main gear, and that is herringbone - everything else is rubber.
The TDR has the open tail gear, and then three more of those in the body. All need backlash. And my torque tube makes a noise in the boom as well, I think those bearing placement discs have some gap, and they can move, which is why they were so easy to slide in.

[Heli G]

At yesterday’s maiden I had a soft tail and upped the rate. Once the gain was upped to 40 (Futaba) the tail was rock solid with incredibly fast piro speed. Even with full punch outs the tail held perfectly. Measured HS was 1650 which equated to 55% throttle if I remember correctly. I will up this to 1700 and 1850 for Idl1 and Idl2. I'm using the Futaba 251 with mini-vbar.
The tdr is very quiet, a lot more so than my 500 - you mostly just hear the blades. I wonder if something is loose in your tail? Did you check the head couplings on the drive shaft? During the build I started wondering how they will hold up…

[Heli G]

Originally Posted by nyc863

And my torque tube makes a noise in the boom as well, I think those bearing placement discs have some gap, and they can move, which is why they were so easy to slide in.

Is this a "rubbing" sound and do you hear it in a hover or when rotating the blades by hand? I hear a slight rubbing in the TT in the area of the rear bearing, but only when rotating the blades by hand. Mick asked Jan about it and apparently this is normal.

[helicraze]

When it runs it presses against the tube and no noise.

If you front clamp is done up to tight then you will get a noisey bearing. When spinning on the tail the gearing is noisy but in flight it should be smooth and quite

[aussiemick]

Originally Posted by Heli G

Is this a "rubbing" sound and do you hear it in a hover or when rotating the blades by hand? I hear a slight rubbing in the TT in the area of the rear bearing, but only when rotating the blades by hand. Mick asked Jan about it and apparently this is normal.

Here is an exert from Jan's email to me about the rubbing noise in the tail boom

Don´t worry about the noise from the driving shaft bearing supports in the boom. This occure only if there is no load at the tail rotor. During flight when the tail
rotor is under pressure the torque of the tube will try to bend it so that the support bearings gets pressed onto the boom wall so that they will stop
turning arround.

Best regards

Jan

Mick

[nyc863]

well, after deciding the 7940TH hitec is really not a tail servo, and putting on a 251 I had on another heli, tonight, powered by its own UBEC, I will see how the noise is again, it may be quieter when the tail is nailed.

[ZuvieleTeile]

@NYC863
did you ever check your transmitter's centering??
With my JR 9303 I could always see 1 or 2% off center, depending on temperature outside.
I set the transmitter deadzone in the main rotor expert menu up to 40 to get rid of it.

KR
ZT

[nyc863]

so far my 11x has been stable at 36 clicks of subtrim for each channel..

[ZuvieleTeile]

I don't mean the subtrim.
I am talking about the correct centering of the potentiometers.
When you look at the PC software of the V-Bar and go in the setup mode to the TX calibration.
Try to move all of your sticks and see, if they center.
Sometimes you might see an incorrect centering at the number. (It does not go back to zero) sometimes you see only a slight difference in the bar.
You can see it even much better at the control panel in the life mode, because there they give you 1600 points instead of only 100.
If this is the case, then you have to go in expert menu of the rotor and increase the RC deadband.
The incorrect centering of the potentiometers after a input might have contributed to your above problem.

KR
ZT

[nyc863]

No, they are always centered. I did mean that. I keep my beady eyes on those sliders every time I'm in that screen, after all, you must look there to get mid-stick on the collective.

They show 0% and rarely the elevator will show one fine line indicating less than 1% out - if I flick it, it goes back to perfect

And the sub-trims on the radio is how I set them at 0%, they've been ~36 clicks on my dx7se for several models for a year (and that gives me 0% centers), and they are 36 or 37 on the 11X (and that gives me 0% center as well). I'd be really unhappy to have to use a big dead band to avoid temperature related centering slop!

Anyway I'll take the little spacer block in the field case and the control panel then go into 'test mode' before flying to ensure nothing has moved, before fully trusting it.

However the two entirely different swash levelling experiences were at the same temp in the same room with the same PC etc etc.

[aussiemick]

Originally Posted by nyc863

NI keep my beady eyes on those sliders every time I'm in that screen, after all, you must look there to get mid-stick on the collective.

I find it much easier when setting up the head to have a pitch curve along the lines of 0, 50, 50, 50, 100, that way you don't have to keep flicking through different screens to make sure you are at mid stick. Somewhere near middle will always be 0' collective.

This is very helpful to me as I fly mode 1 and when checking cyclic (aileron) it is real easy to move the collective when applying full cyclic (aileron) and give a false reading on the pitch.

Don't forget to reset the pitch curve after setting the heli up!

Mick

[ZuvieleTeile]

Oh another one with mode one.
I flew mode 1 a looong time ago in Europe and stopped flying also for a looong time.
I had to relearn everything in the States and also change to mode 2.
As you can imagine not without some costly mishaps.

It it is hard to delete those old files in your head. . .

But your approach then for setting up the head when you fly mode one is a very good idea.

KR
ZT

[nyc863]

I recorded the sound without blades, with tail blades.

Spool up to v low governor setting - this probably about 1200 RPM. It is really loud in a room next to it. Turn up the volume to max to approach how it sounds IRL, and this isn't 1850.

More metallic & louder than a logo doing the same thing. The rattle/grind noise at the end when the motor switches off is stretched out much longer with blades on, obviously, but with no motor pressure I don't expect that part to be smooth.

[ame]http://vimeo.com/13289229[/ame]

No vibe though. I balanced the whole tail hub and all yesterday, the nudge on the frame was me putting my hand on the boom to feel for vibe.

so is this how a TDR sounds without main blades?

[Edvard R]

Originally Posted by nyc863

so is this how a TDR sounds without main blades?

The 2 of mine don't. I think you have some mesh issues, most likely on the motor and/or the tail bevel gear. The tail gear is critical and will be noisy if just a bit off.
I had a Logo 600 before, and without a doubt the TDRs are heaps quieter.

[nyc863]

ok .. I went through it.

tail gear:
both gears meet exactly along length. There is about ~4mm of lash at the blade tip. There is only the faintest of axial play in the tail shaft. It I was to diminish that lash, then the gears would no longer meet exactly along their length.

start of torque tube:
The boom gear is maybe 0.5mm out from meeting exactly along length which in the manual is fine. There is small backlash available (if I was to push it in further the lash would be nil).

engine pinion:
meets the drive gear perfectly even when engine is "pushing", very slight lash all the way around. There is no axial play in the main drive shaft, or engine pinion.

second pinion:
meets the head gear perfectly along length, there is slight lash - sticking my finger in and holding this pinion, the blade head can be moved about 1mm at the end of the bade grip, no matter what the positon. There is the very slightest axial play in the head if I pull/push at the head block between the blade grips. Almost invisible to the eye.

So .. is there anything else to check? I'm honestly stumped, and without hearing another TDR spooled up on video, or in the air, can't tell if the noise is right or wrong.

And .. I really REALLY don't understand how a three dee rigid gear train SHOULD be quieter than a Logo, when in the logo you have a single herringbone mesh, and in the TDR you have not one but FOUR cross cut gear meshes partying hard, and a lot more metal and carbon.

[helicraze]

I would reserve judgement on the noise until you spool with main and tail blades, turning by hand or with no load (no main blades) it will sound bad.

You spool down sounds normal, the spoolup possibly a little noisy but when its running it sounds normal. Did you lube the gears? White servo lithium grease is good stuff.

I am thinking perhaps your motor mesh and front TT mesh is too tight, there should be a clack clack sound when moving the motor/main gear as you need to allow for expansion due to heat.
The front TT pinion from memory on both my helis underneath i used the 1 shim as recommended (above it i shimmed it more) and the TT gear meshes 100% in line with it. Did you put extra shims underneath the front TT drive gear?
You would be suprised it can run with a lot of backlash due to the tooth profile and now being CNC cut (compared to the older molded gears) i have more back lash on my 2010 TDR than the older henseleits.

I remember my logo was not very noisy, the TDR when running (in a hover) was also almost silent, both are quiet in there own ways.

Check the lash as I recommend above make sure there is no vibes and fly it for a bit, everything should settle after a few flights.

[helicraze]

I drew a pic (sorry not the artistic type) to show the front TT gear, and the lower gear it meshes on (if you were looking from the rear of the battery tray.

You can see from the profile of the TT gear that where the red line is, where it changes shape from angled to flat that part does not need to be sitting inside the bottom TT drive gear.

PS i found on my MPXLE too tight TT gear mesh at the front causes some noise and vibration seen in the tail.