Depron Heinkel HE162

Deleted, wrong topic !

Nothing very spectacular but I put it together and took it outside for the first time.

Still waiting for the Rx, at least this time the Royal Mail have acknowledged it is in the UK and cleared customs, so I really must get those wing tips built.

This is one maiden I am really looking forward to, with bated breath !

crash
So am I!
The bit that annoys is that the UK has had a long period of almost no wind which is an almost mandatory prerequisite for the maiden however the weather has already started to change and looks like it is going to be seriously stormy and wet for many days/weeks as the jet steam is pointing directly at us dragging along a never ending stream of low pressure cyclones.

The Lemon Stab rx (and the freebie rx) have arrived. It took just 7 days from Hong Hong. I have sent Lemon a 'thank you' email.
Now just waiting for the UBEC!

Now have both the Lemon stab and the UBEC so some modest progress.
The battery box fitted so the 450 mAh 4s can go right up into the nose.

The UBEC is fitted onto the rear wall of the battery box.

The Lemon stab Rx will go on the fuselage floor just behind the battery box.
It needs a substantial hole cutting in the skin to gain sufficient access.

Eventually most of the cut away skin will be replaced just leaving a hatch just big enough so the Rx can be slid out to adjust the gyro pots.
Well that's the plan.

looking good Simon, does the depron insulate much? can't wait for the finished model, Have you decided on a final colour scheme?

paul
Depron has both an excellent thermal and electrical insulation properties, however fortunately neither the Little Bee ESC or the UBEC produce very much heat. At 11A max I expect the battery and the wiring to get no more than faintly warm.
The maiden will be just a single 3? minute flight. I doubt my nerves or damage repair will allow another flight on the same day.

Nothing positive on a colour scheme.
For the maiden I will likely just give the fuselage light coat of white acrylic as it fills and reinforces the skin a bit. When fully hard it does allows some gentle sanding.
If it flies as hoped then I will start on a scale, but simple, scheme.

I am now at an impasse!
With it all electrically assembled I am sure the servo 'stutter' problem will not be acceptable especially to the gyro stability function.
This video shows the problem. It exists identically on all 4 servos either using the radio or a servo tester.

Note the Sand Rover in the background.
.The servos are all identical and are Y connected in pairs.
The total length of the servo to rx wire is long and similar for all at about 1300 mm.
I have put a ferrite ring on the elevator wire (3 close turns) and it makes no discernible difference.
The elevator servo wire is 'twisted' except for the short length (60 mm) from the Y to each servo in the tail plane.
The EDF motor works normally.

The servos do move to the correct commanded position, be it a big or small deflection, but it looks like there is a significant delay in doing so with the result the servo 'jumps' at speed to the new position.
It is hard to imagine the 'stab' function will work well with this condition.

So either all the servos object to the long wires or the long wires are effecting the Rx & servo tester in some way or it is something else.
Any ideas?

This will have to be 'sorted', at least to a satisfactory level, before any flight will be attempted.

That's a worry! couple of thoughts/ideas...would shielding the wires help? could you use a second rx to keep the wire runs shorter? lastly no offence but are they cheapo servos? Got a well known one ( futaba or savox) you could Try?

I spent much of the afternoon testing stand alone servos (3.7g analogue, 3.7 digital, 5g, 9g & a Futaba 18g) on a long (1500mm) thin (32g) flat wire to give the worst case scenario. All the servo work perfectly normally both on a servo tester and with the Lemon stab rx extracted from the HE162. To be expected the bigger servos do give a better definition to very fine movement but none of the servos demonstrated any 'hesitation'.
To confirm the problem is actually within the He162 somewhere I actually glued a new 3.7g servo under the tail plane in such a way that the link rod could be disconnected and used on the new servo. It had its own1500 mm, 32 g wire lead and was driven by a servo tester.
For comparison the servo tester was then connected to the installed elevator wire to run the servo installed on the other elevator.
The video shows both tests.

From this result I can be fairly certain there is something wrong with the elevator wiring. May be an intermittent short on the Y joint which would explain why it effects the aileron servos as well.
No looking forward to getting the elevator servo wires out. I fear it will require quite some holes to be cut in the skin.

Just for completeness a video of the elevators on the AN124. Two 5 g servos with a Y connection and a 1450 mm wire length being driven by a servo tester.

No hesitation thus baffled by the problem in the HE 162!

Klippy
You might well be right. The next job will be to extract both the elevator servos from the tail plane and gain access to the Y joint so the servos can be replaced with the new pair that worked properly on test using a Y and on the end of the 1500mm wire!

I did test each of the original servos before installation but it is possible that any 'hesitation' would not have been that obvious when powered individually and on a short wire.

Unusually for me I did arrange that the Rx can be extracted so the plugs can be accessed (just!) so if the worst comes to the worst the servo wires could be completely replaced.

We live and learn.

Klippy you were quite right.
One of the elevator servos was definitely faulty.
When extracted and run on the tester 'continuous' mode and left just hanging on its wires you could see the servo periodically twist as the power cut out. The suddenness with which it stopped suggested it was a short rather than just a power cut out which would explain the effect on the other servos on the Y. The effect would be made worse by the resistance of a long servo lead.

Some more soldering & testing required of the replacement servos before the holes in the skin can be made good.