Motor / Gearbox problems when height limiter shuts off

[Graham Lorimer]

I am using a small Hacker motor gearbox combination in a 2 meter RES glider.

The pinion keeps coming loose on the motor shaft, probably because when the Altis Nano height / timer limiter shuts off the motor, the shut off is instant, and putting strain on the pinion. 

Any thoughts on how I can make this shutdown a little slower please?

Graham,

[mikef]

Silly question, but I assume you have the esc set for slow start and a gentle shut down - i have the brake off in an attempt to let the prop find a 'best' folding position.  I have a cut-switch.  Just before launch, I advance the throttle to full with the cut-switch active.  I turn the cut-switch to off to start the motor and let the AMRT stop it at the set height or run time.  Hacker A10-7L, Hacker ESC, 3S 350mAh Hacker eco-x top fuel battery.   My Hacker X-20- Pro settings….

[Gary B]

There are usually programmable start/shutdown options in the ESC (longer time to ramp up or down).

Your brake might have an adjustable setting (soft, medium, hard braking etc).

To save wear on my motor gearboxes I throttle back to idle at launch height then switch off.

Similarly I launch at half throttle then increase if needed.

The Altis is sending a signal to the ESC but it's that device that determines the parameters of the drive.

   Cheers

     Gary

[Graham Lorimer]

Thanks for the replies to date.

I am using a very small BL HELI 32 ESC and have set for slow ramp up, but I have not been able to find a setting that gives a slow shutdown. The brake is turned off but still the prop stops instantly when the height limiter comes in, and is still giving strain on the pinion I would think.

Does anybody have a setting on the BL 32 that gives a gentle slow down after the height limiter shuts it down.?

Graham

[Jef Ott]

Graham,

Your "slow ramp up" is set to go flat out within 4 milliseconds. That's quite excessive. Maybe go for 1% per millisecond instead. 

[Graham Lorimer]

Thanks

Have now got the start and stop quite soft, so that should solve the pinion problem, but the issue I have now is when activating the throttle switch (ready to apply throttle and launch) the motor turns a little and stops, could present a slight danger to fingers.

Any thoughts?

Graham

[DaveH]

57 minutes ago, Graham Lorimer said:

Thanks

Have now got the start and stop quite soft, so that should solve the pinion problem, but the issue I have now is when activating the throttle switch (ready to apply throttle and launch) the motor turns a little and stops, could present a slight danger to fingers.

Any thoughts?

Graham

 

 

That could also start your Altis timer...   This new problem sounds to be from the OpenTx system.   

Mine also had a similar problem where the throttle could get a 1/2 second burst as I switched to the mode in which the throttle was enabled.   I could see it happen on the channel monitor. It would start at 0% (middle stick position) and quickly decay to -100%.      So far I have had to work round it.  I fixed it by disabling all "soft" starts within the config (OpenTx, not the ESC).      My guess is that when switching modes (or possibly the throttle kill too) it assumes a channel value of zero and instantly reduces to where it should be.  Only a problem if that change is slowed by a soft start option.    

I have not progressed this any further yet, the preferred option is to do via the ESC config.    

[Graham Lorimer]

Thanks DaveH

When originally trying to set up OpenTX so that I had a Soft start and Soft shut off, I set those in the transmitter, but to no avail.

I have now achieved what I wanted on the ESC Heli 32, but had not taken the earlier settings from OpenTX. Following your advice, set OpenTX on zero delayed start and slowdown, now all is good.

Bottom line .......... all this must be done in the ESC, not the transmitter.

Many thanks

Graham

[DaveH]

That's great...a fix!        I think that the problem we have both seen is a bug (sometimes called a "feature") of the OpenTx system. I had thought of replicating the problem with a minimal setup, then reporting it to the developers... but...  as I run 2.2.4, their first response is likely to be  "have you tried the latest firmware?"  (I'm happy with it as it is, unless I know that this has been fixed).    

 

 

[Jef Ott]

3 hours ago, Graham Lorimer said:

Thanks

Have now got the start and stop quite soft, so that should solve the pinion problem, but the issue I have now is when activating the throttle switch (ready to apply throttle and launch) the motor turns a little and stops, could present a slight danger to fingers.

Any thoughts?

Graham

Often another set of eyes is all it takes.

Glad I was able to help you with reading the info that the ESC was giving you.

Well done for posting the graphic, I am way behind on this technology so had never seen this type of screen before, much better than listening to, and decoding, beeps!

Jef

[AnthonyB]

This has been a common problem (for me) for the last 20+ years....... The pinion for a gearbox.

It started when I wanted to change the 3.7:1 ratio – the only gearbox Aveox had. I wanted 6.7:1 for F5B use. I got all the bits to add the new ratio, including the pinion. I really did not fancy just glueing the pinion on. So I went to see a friend from school that had an engineering supply shop. I had been told Loctite xxx..... Whatever the number was. He said “will it get very hot” and I said “probably.” In the end he gave me a bottle of liquid - “This is what you need.”

Subsequently, needing to dismantle, you use a soldering iron or a blow torch to warm up the joint. Some adhesives give lose straight away, upon heating. This really holds on – too much.

I have done (see photo – going down) Kontronik pinions for F5B, Cosmotec boxes for E-400 and various Maxon for various things and Aveox / Neu. No pinions have ever come off. And when you want them off, it is a struggle. Even the Astro boxes.

I never really bother with soft start or soft brake – none have ever come off, so I never bothered.

The parts that you have to be very very careful about are being spotlessly clean (no old residue included) and when you slide a pinion (even “press”) onto a shaft – there is adhesive on the shaft and there is a really close bearing on the motor. This is a runny liquid and NONE must get near the bearings.

 

 

[AnthonyB]

The bottle has changed over 20 years........ https://www.airevelobearings.com/product/delta-55-high-strength-permanent-50ml/