sjm 400 v3 pinion help

[heliboy88]

Hi guys,

Does anyone know whether i can use the 0.5 MOD pinion with the sjm v3?
It's 0.4 MOD(listed) and i really can't find the pinion anywhere. Or is there any known substitute for it? Cus the pinion that came stock seemed to burn my motor (it's too HOT even after 5 mins hover) and puffed my 2 new packs. I've checked everything and there's no binding everywhere. I really think it's the T of the pinion. BTW, it's 15T that came with the kit. And i asked the online shop they said they'll order a 12T or 13T for me but recently they just told me that the pinion that arrived was a 14T :bomb: Pls help me guys, i'm really worried to fly the heli now, it's been on the shelf for a month after just a few hovers.

Thanks a lot for any help i can get.

Best regards,
Rich

[PTFlyer]

I believe the motor that comes with the sjm400 has a 2.3mm shaft.....

Knowing that, you should be able to get a pinion from any number of places.

Helidirect has them......

http://www.helidirect.com/index.php?cPath=78

[Danyboy]

Rich,

Don't get me wrong...

But what is a SJM-400 V3?

As far as I know, there is only the 400, then the -pro which has the newer head, and then the V2, which has the new chassis along with the new head and golden alu-parts instead of the previous ones with grey.
Typo? Invention from a dealer?

Why I ask...

With the kit, there should have been three pinions, 10T, 12T and 14T.
With the 12T, the headspeed is at 2400RPM on 0° collective and 75% throttle, which will bog a little under full collective (2280RPM@11°+100%throttle). The motor does just get a bit more than hand-warm after a 9min flight, with outside air temperatures of about 20°C.
With the 15T you mention, headspeed must be insane, but I imagine there would be a lot of bogging going on... But you say you were just hovering? I couldn't imagine that would load the engine that much, even with 15T...

What I did find out though, that during startup, the ESC uses a different motor-timing. It must be something quite aggressive, because when I did quick spool-ups once to check and adjust blade tracking, I had a smoking motor after 7 spool-ups in succession. Couldn't still touch the motor after 10mins...
Don't ask why, they can't explain, but this really seems to be an issue. Do it three times, and you can feel more heat than after a 9min flight...
Maybe that could be the reason for your heating?

If we're talking about a dealer's V3 invention (like with the T-Rexes), that would be something like a V2 with the upgraded tail, and you have the same main-gear as I have (180T), I would recommend the 12T pinion for the motor. That would give you a lower headspeed, but less bogging.

Cheers,

Daniel