When I ordered the Heng Long V2 torsion bar Abrams, it is stnadard procedure that I also ordered a ball bearing gearbox, high end 390 motor, metal sprocket and idler wheel. The Tamiya track for Abrams is more difficult to find when Tamiya shop did not restock it. I got a used Tamiya track for Abrams 2 months later. Before that I ran a spare Tamiya track for Leo.
The Abrams came with a cracked torrent which caught all my early attention. I installed the Heng-Xin gearbox while waiting for the replacement parts for the broken torrent. I used a TK-7.0 MFU and everything seems to work fine. Problem creep up when I moved the TK-7.1 MFU to the Abrams. The TK71 has been working fine in the Leopard2A6 for many months. In the Abrams, the TK71 keeps shutting itself off after a minute or so running. The only suspect is the red 390 motors.
I replaced the red 390 with Mxfans 390. The TK71 is now working at max speed for long stretch of time.
https://www.amazon.com/dp/B075RZLVSG?ref_=ppx_hzsearch_conn_dt_b_fed_asin_ti tle_1
I learnt a few years ago to use only genuine Mabuchi 300 series motor. The Mabuchi use ball bearings in their motor while the Heng Long motors have sleeve bearings. I made a series of motor case temperature rise measurements. The Heng Long 380 motor temperature rises significantly more than the Mabuchi's. I also compared the Red390 to the ball bearing Mxfans390. I attributed the similar temperature rises of the 2 390 motors to the fact that both have internal cooling fan. However, the recent experience of the 2 390's with TK71 MFU has convinced me to use only ball bearing motors. The sleeve bearing motor draws too much power from the tiny ESC in the HL radio MFU. It never hurt to be more careful.
The next step is the setup of the servo barrel recoil.
The Abrams came with a cracked torrent which caught all my early attention. I installed the Heng-Xin gearbox while waiting for the replacement parts for the broken torrent. I used a TK-7.0 MFU and everything seems to work fine. Problem creep up when I moved the TK-7.1 MFU to the Abrams. The TK71 has been working fine in the Leopard2A6 for many months. In the Abrams, the TK71 keeps shutting itself off after a minute or so running. The only suspect is the red 390 motors.
I replaced the red 390 with Mxfans 390. The TK71 is now working at max speed for long stretch of time.
https://www.amazon.com/dp/B075RZLVSG?ref_=ppx_hzsearch_conn_dt_b_fed_asin_ti tle_1
I learnt a few years ago to use only genuine Mabuchi 300 series motor. The Mabuchi use ball bearings in their motor while the Heng Long motors have sleeve bearings. I made a series of motor case temperature rise measurements. The Heng Long 380 motor temperature rises significantly more than the Mabuchi's. I also compared the Red390 to the ball bearing Mxfans390. I attributed the similar temperature rises of the 2 390 motors to the fact that both have internal cooling fan. However, the recent experience of the 2 390's with TK71 MFU has convinced me to use only ball bearing motors. The sleeve bearing motor draws too much power from the tiny ESC in the HL radio MFU. It never hurt to be more careful.
The next step is the setup of the servo barrel recoil.
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