8 tooth pinion

[aramsdell]

I've had (3 ) 8 t pinions. These are option parts on HeliWorld site. All 3 have split and lost a tooth. None resulted in a crash but could have . One broke on a 550+ motor. 2 broke on a 600+ motor. These were on my AP Swift , no 3D or really hard acceleration etc. These pinions are just too thin for a 5mm motor shaft.
If you are using one beware. I'm going back to a 9 T.

[RAV50]

Yep - that is probably why Century, for almost 2 years, did NOT want to release an 8T pinion. But so many wanting lower head speeds kept asking for them, so they probably finally succumbed to the demand.....kinda hard to go against demand.

Personally, I could not see one wanting to go less then 9T - As there are better ways to get lower head speed then just going to an 8T pinion.

For AP work, if you want stability and longer motor runs from lower head speed, you have many power options.

Using lower relative head speeds on longer blades (e.g. 550mm) using lower collective pitch settings, will generate more efficient "lift" then will shorter blades at higher head speeds and higher pitch settings.

With the 1110 KV rating of the 600+, going with a 5 cell pack and a 9T pinion and good 550mm blades, will give you a head speed of 1635 or so and generate a lot of lift, at a relatively low current draw. You could even go to a large capacity 4 cell pack and a 11T pinion for a similar rotor speed (1600 or so). But your flight times would not be quite as high for the same "mah" rated battery packs.

If you want even lower head speed, you can use the 4 cell pack on 10T or 9T pinions.

Here is also where heavier, more stable flybar paddles will also be of use. Going with a set of Hawk paddles, for example, will also make it much more stable - specially in gusty winds.

[aramsdell]

Rav50, I have flown mine on 4S packs and 10 and 11T.
Flight times quite short with 4000 Max amps and 4S FP3700. I went to 9 T with 5S pack and 5S Rotortechs. I swapped in an 8T when I got a 6S pack. The 5S flies great on the 8T also with the 550's.
I even had this setup running on a 550+ motor with the 5S pack and the 8T(that's why I got the first 8T). The 550+ IS a 4 cell rated motor but I figured lower the pinion and go easy on the throttle. This setup worked great for about 100 flights. It finally had a problem while hovering in the driveway. Set down and the windings had come loose.
I had asked long ago whether the 550 could handle 5S and now I know. No.
Back to 8T stuff. My 7+ lb helicam has good headspeed with the 600+ and the 8T and 5S pack and 550's. It has really good headspeed with the 6S pack. Now that I am going back to 9T that 6S speed will be even greater and wasting some energy unless I dial back the top end a little.
That is itself a little counterproductive.
My other Swift is a blast on 9T and 6S,RT's.