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Aug 17, 2019, 08:05 AM
Boaters are nice people.
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Small update; I took the FP mini heli apart and connected the ESC and 4500Kv motor to the swashplate servo position on the board.

For testing, I use a seperate battery for the heli and the extra motor, so I don't have to fiddle with crocodile clamps on the circuitboard, which in the past has created more mishaps than I like to remember.

As both ESC's have BEC, the led on the circuitboard already lights up before the heli battery is connected, I'll pull the red wire if this option is a viable one to avoid BEC mayhem (or just not connect the red wire when soldering a parallel lead onto the board).

As the servo signal/stick is in the center position, the brushless motor doesn't start, unless I move the left hand stick (main rotors) forward, it now starts to run at half throttle, as the brushed motor test showed.
As with the brushed test, right hand stick full forward makes the motor stop, full reverse makes it run full throttle, within the restriction that the servo signal isn't 100%, so the outrunner only runs at half throttle, I estimate.
RPM wise not too bad, but running permanent partial throttle tends to heat up both ESC and motor, I'll have to see how bad this gets in the open frame with all the air passing through.

What is odd though; once I stop the outrunner by pushing the stick all the way forward, it doesn't restart when I throttle up again with the main rotors stopped, only when I engage the main rotors, the outrunner will run too.

No idea why this happens, but it may be a good thing; the pusher prop not running while the main rotors are not running too.

With the servo reverse, the outrunner ESC will work the right way, but will always run at partial throttle upon lift off, so if I want to be able to hover, I'll have to pull the stick back.
Curious as to how this will work in practice...

Regards, Jan.
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Aug 17, 2019, 10:42 AM
Boaters are nice people.
Thread OP
As I'll have to wait for:
1) the wind to die down in order to testfly the heli in stock form,
2) the servo reverse to arrive,

I started to see how to mount a second servo in the frame; as the left and right metal parts are different, this requires some adaptation, or me ordering a set of metal parts, of which I'll just use the left side to mirror the right side regarding the cut-out for the servo.
I'll hold off ordering that until I know which movement the servo arm needs to make to work with the left/right turning of the heli.

As a temporary solution I can mount the servo on the outside, turning it to accomodate the correct arm movement.

So far so good... the short linkage that normally connects the swashplate onto the frame is a very short one, with no room for a longer rod (without demolishing the thread inside with no garantee it'll hold when vibrating in flight).

Unfortunately the 'local' shops that sell parts for the T-40C don't stock the long connection between servo and swashplate, so I ordered one from Aliexpress.
3) long connection for second servo to swashplate:

I'll put the heli back together again and wait for the wind to pipe down.

Regards, Jan.
Aug 17, 2019, 11:54 AM
Boaters are nice people.
Thread OP

Old age must be catching up with me...

Playing around with the heli some more, outside, holding it in my hand, I found out I made a mistake in post #21; the second servo would not be parallel on the turning left right on the right hand stick, as this function is on the left stick: up/down is throttle, left/right makes one motor speed up or slow down to turn left or right.

This also explains why I couldn't get the heli to turn back to me the other night when it was carried downwind; I just moved the wrong stick.

So, when I manage to get the second servo to work, it works on the right hand stick moving left and right, making the heli roll left and right, as far as the flybar will allow such action, that is.

To sum it up:

Left stick up-down: throttle main rotor.
Left stick left-right: turning left/right.
Right stick up-down: forward/reverse (in future with pusherprop assistance)
Right hand left-right: roll left/right if the second servo is operational.

Mode 2, as I'm used to with my boats, except I only use two sticks; throttle on the left, rudder on the right, hence my confusion when the wind took the heli, I instinctively acted as if the rudder was on the right stick, and ofcourse nothing happened...

Regards, Jan.
Last edited by pompebled; Aug 18, 2019 at 04:48 AM. Reason: typo
Aug 18, 2019, 03:22 AM
mono's Avatar
Old age must be catching up with me...
ditto amigo
and sometimes that's not the half of it
I don't know how long I spent doing a detailed response to your last 4 posts with links to various things, then the browser crashed and I lost it all.
No way I can duplicate it, but will give it a go shortly... after I've had a good cry.
Aug 18, 2019, 03:55 AM
Boaters are nice people.
Thread OP
Hi Patrick,

When that tends to happen, I write my text in Word, or some other word processing program on my computer. When ready, I copy the text onto the forum.

I know from experience how frustrating it can be when you just typed an extensive reply and the electronics mess it up before you can hit 'send'...

Regards, Jan.
Aug 18, 2019, 07:23 AM
Boaters are nice people.
Thread OP
Hi Patrick,

When you're done crying, could you take a look at the picture and give your opinion?

As you can see, I've taken off the tailboom and positioned the outrunner with the 5x5 prop just outside the downwash of the main rotors.

The tailboom assembly with the two supports weighs 46 gr, so I don't have a lot of margin to work with as the outrunner weighs about 36 gr (hard to weigh, as the ESC is soldered onto it).and I have to whip up a mount for it, preferable adjustable in angle, as the two carbon rods were just stuck in the M3 holes at the rotor side of the motor.
Just two rods is too flexible anyway, but adding one or two more is no problem.
I also need to make some kind of support, so the prop can't hit the ground when landing, maybe extend the skids for testing purposes.

- Should the pusher be further back from the downwash, or does scaling down reduce the effect the downwash has on the pusher?
- Will the 5 x 5 prop work (well enough), or do I better look for a multiblade (drone) prop that is smaller in size?

On another note; playing around with the controls and the heli in hand yesterday, I had some disturbing noise when turning left or right (left hand stick)in the transmission.
As this is a simple reduction, it was either the motor coming loose, leaving too much play on the gears, or the gears themselves.
I found the setscrews in the lower gear, holding the top rotorshaft worked themselves loose, despite the use of nailpolish to secure them.
The grease from the lower bushing had turned the shaft and screws black(ish).

Clean and not use grease on the lower bushing, just a drop of oil after the nailpolish has set? I don't like to (have to) use threadlock on these small bolts, as loosening the threadlock requires heat, which is a bad idea with the plastic main gear
I'm not sure if this would have happened in flight, as holding it in hand made the vibrations more severe, it seems...

Did some more work on mounting the pusher propmotor, see picture.

Regards, Jan.
Last edited by pompebled; Aug 19, 2019 at 03:57 AM. Reason: Addition.
Aug 19, 2019, 08:47 AM
mono's Avatar
buenos dias amigo
after reading your last few posts, it seems that quite a bit of the content of my lost post would have been superfluous anyway, so probably just as well it vanished.
With no club nearby, I'm on my own learning how to fly it and the fact windless days rarely occur here ...
A flight sim is the ideal solution for that.
What sort of radio came with the 6ch heli? Perhaps it has a trainer / sim port.
until I know which movement the servo arm needs to make to work with the left/right turning of the heli.
I came across a close up pic of a T40 swashplate. Does yours look exactly like that?
If so, one of the link arms has stunted growth, which would liven things up a bit.
They should normally be the same length.
Do you have a suggestion on which motor to get?
For a brushed motor, something in the 130 - 180 range would likely do the job.
In brushless, the 18xx - 22xx range in a low kV.
But you need to look at the thrust and amps draw data with different prop sizes, for any motor choices.
Should the pusher be further back from the downwash?
It would benefit to be well clear of the rotor disk perimeter, but how much it affects the bottom rotor thrust (and vice versa) is speculative.
Except that, the further away, the better.
Will the 5 x 5 prop work (well enough)
I don't see why not. There are plenty of planes that just use one of those, so a heli only needing a bit of a nudge is nothing really.

ta ta for now
Aug 19, 2019, 01:12 PM
Boaters are nice people.
Thread OP
Hi Patrick,

Thank you for responding!

Ten years ago I used the FSM sim that came with the 6 ch heli, using the port on the TX. Today that sim isn't compatible anymore with my current computer layout, I'd have to look for something else and use my FS-CT6B, which also has a port to connect it to the PC (for programming purposes, but if it sees all sticks, it should also be able to control a sim, don't you think?)

The picture you linked to is indeed the same swashplate, it's upside down in the picture, as it's mounted the other side up on my heli.
The long arm is currently connected to the forward/reverse servo, the short arm is attached to the frame.
If I connect that one to the second servo, I'll make sure to use a similar short arm to avoid having an out of control roll movement, fortunately that servo also has a limited throw and moves slower than the stick movement, so I have good hope...

I've been working on the mount for the small brushless outrunner in the pictures, due to the limited throw of the forward reverse servo, the outrunner won't run at full power, effectively making it work in the Kv range you mentioned, another bonus point.

I haven't fixed the rods to the frame yet, so I have about two inches to play with, closer or further from the lower rotor.

With no rain, but a lot of wind, I've been bolting up and down the canal nearby with my 30" Arowana speedboat, 'scary stuff' running close to 50 mph in a straight line between brick walls and into the strong headwind, making it want to take off.

Thanks again and when there's more to show I'll let you know.

Regards, Jan.
Sep 02, 2019, 02:22 PM
Boaters are nice people.
Thread OP
Tiny update; the servo reverse showed up and I've got about 50% of the pusherprop support in place.
Unfortunately we had a few days heatwave, so working in the hobby shed was no fun, and guess what, those hot days there was no wind, basically good days to test outside, if I would have had anything tó test.

The next two days is work, more hobbytime after that.

Regards, Jan.

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