Swift 16 pinion size

[RabelRouse]

:confused: I am currently running a century 550+ motor and a 4s1p with a nine tooth pinion. If I use the original century 600 motor not the + what pinion will I need to still run the 4s1p to get a decent headspeed for simple sport flying and what npinion will i nedd if I want to up to a 5s pack?
Thanks ,
Jeff

[Spidious]

Punch your numbers in here >> http://dhrc.rchomepage.com/calc.htm

[Greybird]

For about the same headspeed you have now, the 600 with an 11 tooth on 4S, or the 600 with a 10 tooth on 5S.

[Cyclick]

The older, black outer cased 600 (before the +) had a KV rating of only 800 compared to the silver outer cased 600+ that has an 1110 KV. And the 550+ has a KV of 1470.

That means that with your 550+ and a 9T pinion you are getting about a 1800 head speed at a 100% ESC setting.

1470 x 14.8 = 21756
The 9T pinion gets you a 10.67 gear ratio (96 main/9 pinion)

So at 100% efficiency you would get 21756/10.67 = 2039

At a more reasonable 90% efficiency that would be about 1835 (2039 x 0.9)

Doing the math for your older 600.

800 x 14.8 = 11840
11840/1835 = 6.45
96/6.45 = 14.88

The largest I know of is the 14T, which would give you a ratio of (96/14) 6.85, so using that you would still get a flyable rotor speed at 90% of (11840/6.85 x 0.9) 1555.

Your cyclic and collective would be noticably softer, but yor flight times would be noticeably longer.

[Greybird]

Cyclick. I think on those calcs, ESC setting is not a factor. They want motor efficiency. (I might be wrong though) The Z's are 83% efficient. If you pop your motor apart, the KV might be written in magic marker on the inside. 3 out of the 5 I have are.

[Cyclick]

Greybird,

The reason I mentioned the ESC setting at 100% is because after giving pinion advice to someone. He cam back to tell me that he was not getting anywhere near the rotor speeds I was saying he should get. When I met him at the field and went over his set-up, I discovered his ESC setting was at 70%!!! SO now I try to always make it clear that the expected rotor speed can only be there is the ESC is st at 100% - as though it was a straight wire.

[RabelRouse]

Thanks Guys,
So if I go to the 600a with a kv of 1110 an 12 tooth pinion on 4s would give me a head speed 1848 at 90% and a 10 tooth with 5s would do 1925 at 90%. Am I right?

[rotoraddict]

Using 90% as your efficiency figure - with the silver cased 1110KV motor, that would be about right.