Does anyone have any experiences in Airtech Germany's eGear sets? especially for the size of Carf ViperJet? I cannot find too much comments from web.. If you already have or consider buying Airtech Germany's eGears I strongly recommend to read this lengthy posting.
I ordered one full set and received it lately as I trusted in the company's reputation from the "air cylinder era". Erwin's service was excellent in the beginning and mechanical quality is good but ...
Aircraft Germany (Erwin) stated by email that brakes can be used with 6-14v supply. I tested it with 2S LiPo but found the brakes very very weak. Resistance of magnetics is ~90Ohm (measured) so with full 2S LiPo braking current is only ~90mAmps. Erwin claimed it will work well with 3S or 4S LiPo even currents are small. I didn't test this yet as I don't have suitable LiPo on hand at the moment. I'm kind of hesitating 4S LiPo as it goes beyond 14v limit that Erwin stated earlier and also not supported by the controller he provided. Have anyone found if 3S LiPo for brakes is enough for Carf ViperJet size brakes with Airtech Germany system? Have anyone used successfully 4S LiPo?
THEN the really NASTY problem... I really cannot recommend AirTech Germany electric gears to anyone. I actually recommend everyone to keep your models grounded until you have done some measurements to verify if your eGear's integrated controller is same version as I received! It has potentially FATAL problem if you use your gear with 2S LiPo or with requlated ~7V! Have anyone burned your plane yet?
During first trials (maybe 30s or so) of AirTech Germany's gear actuator I used full 2S LiPo as instructed. Suddenly the gear started to move intermittently and then stopped with smoke coming out from the retract unit. Servo wire was melting and I lost also some Y-cords. Luckily Y-cord saved my receiver and the gear was not yet installed to airframe so I was able to cut supply very quickly. Please see the picture about the result here:
Apparently there was some serious internal short circuit. I emailed to Erwin about the problem and the immediate response was
Whattttt???? Airtech Germany gear was smoking and it's my mistake?? I asked what he means and the response was:
"I know what you did
You won't the motor faster
Then you use 3S Lipps
The motorelectric burns
Yoj open case .......
No worrenty "
and then he keeps repeating the following as a response to all emails. He also ignores all the facts:
I know what you did
His first key point is that I used 3S LiPos... No I didn't. But apparently Erwin has some paranormal capabilities to "know" what I did!
His second and last point is that I opened the case: yes. I rolled the cover open with fingers to take pictures for him: no tools required, no seals etc.
Key point is that there is clear design or/and manufacturing problem in the device but instead of taking care of clear product liability problem Erwin starts being offensive towards me with comments like:
"Or the better option for you Air Zylinder" and
" Funny Guy".
Because Erwin denied warranty I replaced the burned servo wire just to verify the root cause was not only short circuit in poorly soldered wirings. Didn't help: it's working only partially. Then I investigated both fully working and the broken controller units more and found a very concerning fatal problem. I tried to inform Airtech Germany friendly way about it but Erwin just keeps insulting me as a result. I know one company that I won't do any business anymore.
I measured VCC voltage of Microchip controller on the eGear PCB and with full 2S LiPo it's whopping 6.25V!!! Operational Voltage specification for Microchip 12F1822 is only up to 5.5V. Microchip is not guaranteeing controller being functional with such high VCC! The system has very very BAD design mistake (or wrong component used during the manufacturing). Everyone can verify this by measuring voltage between pins 1 and 8 of the uController while it's powered with 2S LiPo.
Therefore my educated guess is the following (I cannot be sure but this is probable scenario as I didn't use 3S LiPo):
1) Microchip 12F1822 got confused/corrupted/stopped running valid code due to too high VCC
2) FETs received invalid control signal
3) wrong FETs activated simultaneously causing direct shortcut.
Date code on Microchip PIC is 1417 (wk17 2014); this is probable to be same for the whole batch so if there was uncontrolled production variation between batches it's probable to exist at least on the boards with this PIC version.
If you are using the gears for sake of your own model's safety please check your controllers before continuing to use them (ie measure your uController's VCC). If you have this faulty version it's pure Russian Roulette when it explodes! Please remember that once it breaks Erwin will just claim that "He knows that You used 3S LiPo" which is not permitted and refuses all responsibility. Luckily I saw this before the gear was installed in the plane.