nitro for weekends

[xircom]

strange, just I checked the rx battery (JR NiCAD 4N1900) with voltmeter, and shows 5.15V - then charged it, charger stops after 632mAh only with 5.8V, means that battery wasn't probably empty, uhmm -hopefully it's not the servo or gyro...

[xircom]

which is actually strange (above), because although I flew about 6 tanks and worked around with mostly rx on during 2-2.5 hours, I am wondering if it only took 632mAh - I think would be more, and I have to check charger and battery (e.g. some cycles) ?

[Jafa]

Well, my flights (aero and some 3D) normally use 350mah per flight
Hovering would use less

Maybe a connection came loose?

Is the JR NiCAD pack for planes? I assume it came with the radio.
I don't use those on a heli - the heli can draw peek currents
that average packs can't deliver
I like Sanyo KR1700 or any cell with 5mohm per cell internal impedance
(consumer rechargeable batterys have 25mohm)

[xircom]

Well, in this case I spent more than 632mAh for sure, because I worked around on it about 2hrs and also had 5 flights. I will try to cycle the battery a bit - I checked all connections, seem ok.

I don't know if it's for planes or heli, it's the JR 4N1900, don't know internal resistance either, but seems good quality pack (i.e. not consumer), the experienced shop owner recommended this one, knowing what heli I have.

I still have a DualSky BEC around (3 Ampere) http://www.helidirect.com/product_info.php?cPath=93&products_id=1449 is 3A enough ?

[Jafa]

3A is enough for BEC
But why do you need bec?
You should run this pack direct into your electrics - no bec

[xircom]

ah I know, sorry - wrote confusing, I was thinking if above pack isn't good enough, I could get for example some Lipo and use that UBEC ...

[Jafa]

Well, I have used Sanyo KR1700 so your 1900 pack should be good enough

Make sure revo mixing is off in your heli?
It would be good to find the reason why the heli did the piro

[xircom]

yes revo mix is off - using HH gyro.

Actually in the 5th flight and after about 2 hrs (which is probably draining an RX battery), I realized that the heli using same gain started to shake a bit tail in fast forward flight, then I increased gain a bit. At the end it did some 2-3 quick 90deg turns while hover within 45 sec or so, then I thought it's better to land, and and before I landed also a 360, which I quickly took it down, one main blade cut some grass, but then it was ok.

I could not detect any loose linkage or so, also servos moving correctly today. The VoltSpy at that time was over middle with no load. If you use 350mAh per flight, I might use 300 or so, all servos also digital, for 5 flights and also I worked on the linkage with RX on. 5 x 300 gives already 1500, and maybe some drain during standby maybe makes the battery even more empty..?

what do you think ?

BTW, I flew the mixing arm in "auto stabilization", but now I changed, is this a big difference ?

Thanks !

[Jafa]

I only ever do four flights before charging - so I assume you were low

There is not a big difference in the mixing arm setting
Much bigger difference in reaction time by removing all weight from the paddle
But I don't reccomend cos the heli will pitch in forward flight
Better to get V Paddles when you start do 3D

[xircom]

Just flipping through some OS glow threats, and one of them says too lean engine could cause tail twitching, just because motor not running stadily... besides the low battery voltage, that I assume could also be a reason. Looking through more, most of the people recommend around 1,5 turns - downto 1 turn makes me a bit worried now, is that for OS50SX-H ?

[Jafa]

The SXH and the Hyper versions tune very similar (almost same)
The American posts saying 1.5 turn on the needle will be for 30% nitro
Have to be really careful with needle setting advice

When too lean, the heli will have numerous vibrations and even look nervous
But it will not go into a mad piro...

[xircom]

Oh I see for the 30% it's around 1.5, but for 23% it's somewhere 1.25 to 1 ... understood, thanks !

[xircom]

Jafa, which one you think is the best governor (well, not necessarily most expensive) for this set-up ? Once I mastered the throttle curve and pitch, I am thinking that would be a good investment ... so when I flip the pages, I can think of Futaba Gv1, CSM Rev Lock or Throttle Jockey Pro are the most common, whereas GV1 of course is easiest to get for me in Jp. Thanks !!

[xircom]

Jafa, I am sorry - probably need you help, today it piro again !!! But this time quite high altitude, could not catch it anymore ... so if you have time ... see http://www.helifreak.com/viewtopic.php?p=236634#236634 (put it under electrics, as this is not just an EVO problem maybe). Thanks so much :WOW

[Jafa]

:WOW :arggg: :bomb:

[xircom]

bought a Futaba GY502 (401 sold out that time) and sent 490t/810G combo to JR for review, let's see what they come up with ...

after next couple of flights I hopefully will have a good idea about the throttle curve and engine tuning, so that I will be able to use a gov. Different people suggested RevMax, so ordered one. In the maunal it says throttle ATV as close a possible to 100%, but now I have plus value 135%, shall I change then the servo wheel and linkage ... or does that one remember the calibration normally ?

Thanks a lot,

[Jafa]

You need to change the setup and get your throttle ATV close to 100
Move the ball on the throttle servo out

Calibrate the RevMax
When installing and removing RevMax
you have to check the throttle throw (ATV) as they change with RevMax/TJPro

RevMax is very good

[xircom]

Understood - very nice, thanks a lot ! :D

[Jafa]

Sorry - my answer was too fast - one thing I want to explain
If you ever remove the RevMax, re-check your throttle ATV's
You could be binding and burn out the servo
This is cos the ATV values change with M/A Gov

Just a little thing to watch out for

[xircom]

I see. Thanks very much for the hint, I was wondering already why it needs both calibration and also adaptation of the ATVs and linkages, would be nice to have this box adapting to current 0-135% servo throw. Anyway this is just as it is, and of course I still have some flights ahead to tune it without the gov.

One another thing I realized now with the GY502 (401 was not on stock), that the values the gyro shows for the sensitivity does not match with the percentages the transmitter shows, so it's not 1 to 1, but probably linear. I cannot even reach 100% in HH with 100% on gain, so I have to adjust ATV for this as well ?

Thanks a lot,

[Jafa]

100 on the gain should equal 100 on the Gyro
(100 - 50) * 2 = 100

Does your Gyro setting in the TX have a fancy mode?
The Futaba has Std and GY modes for setting the Gyro

The 502 should be run at 36 to 38 AVCS
Which on a normal ATV would be 69 I think
(69 - 50) * 2 = 38

[xircom]

hmmm

when I use JR TX RUDD D/R Gyro function (Menu GYRO SENS), then on the Gy502 has a display

80% on TX, then gyro shows 44% AVCS (HH) mode - and
20% on TX is 52% Rate Mode.

90% is 60% HH
10% is 68% Normal Rate Mode

100% (max !) is 76% HH
0% (min !) is 84% Normal

502 is in CMT mode

I don't know why this is the case, I checked all the mixes, nothing, ATV is 100/100.

[Jafa]

Hmm, does D/R mean dual rate?
You don't want dual rate on the Gyro Gain Channel - need full ATV rate/coverage
The figures do look like the gyro sens/gain channel is on a dual rate
RUDD & GYRO SENS are two different things - normally

Sorry I am not very helpful, I don't know the JR9x much at all

[xircom]

yes, that's what it means, never thought about the name, indeed confusing ! Manual says

Gyro Gain
The Function Menu List is accessed from the Information Display Screen by pressing the LIST key. From the Function Menu List, rotate the Scroll Bar to highlight the "GYRO SENS" menu choice and click the Scroll Bar. The Gyro Gain may be controlled by the Rudder Dual Rate switch or by the Flight Modes (AUTO) and to use this facility, the Gyro Gain lead must be plugged into the AUX2 receiver channel.

To select an activation switch, highlight "INH" (or previous selection) at the top left of the screen by rotating the Scroll Bar and click on it to bring up a browse box of the available choices. Rotate the Scroll Bar to highlight the required activation method and click to exit the sub menu. To inhibit the Gyro Sense feature, select INH.

If the Rudder Dual Rate switch is used to activate the Gyro Gain, two gain choices are available (Pos.0 and Pos.1)

That's what I did. Of course later I will use the flight modes, but if it goes wrong already with this RUDD D/R switch ... hmmm

[Jafa]

Hmm, confusing! Gyro Gain is indeed what you want to set
I assume the gyro wire with one lead is plugged into the RX aux2
Other than that - not sure - cannot see the problem
You need a JR expert :arggg: