what headspeed will i have

[3sgte]

ok, i thought i had my headspeed all figured out using the readyheli hs calculator but just want to make sure..
i will be running the revco 68t/61t and a 21t pinion a z30a 1100kv motor all on 6s. what will my hs be? i calculated it at around
2349rpm with 100% efficency and 2232% at 95% effc.
does that sound right? thanks

[ukgroucho]

Seems reasonable. Try aiming for 2100 - 2200 to start with and check out the amps and overall flight times.
My experience with a z30 800Kv is that it is very efficient.

[bstock]

I checked against my spreadsheet... and your HS figures are spot on.

I agree with UK - I would reduce the HS a little... saves you battery life so you have more flight time, and unless you want to do hard 3D (maybe you do) - you don't need to spin those blades that fast.

A 20t pinion gets you down to 2237 at 100%, and 2013 at 90% efficentcy.

19t is 2125 at 100 - and 1913 at 90

If you are after basic sport flying - I would consider the 19t - just so I could fly around longer, and still have decent performance.

I saw your thread this weekend... and I would have posted back sooner - but my spreadsheet was at work. ;-)

[ping]

Whats the formula for calculating the HS with the hurricane gear train? I'm also running revco gears so my 1st gear is different from stock.

[ukgroucho]

Work out your gear ratio first
(pinion tooth count ÷ primary tooth count)x(one way tooth count ÷ main tooth count)

So with (e.g.) RevCo 22t pinion, 68t primary (front) gear, stock (19t) one way pinion and 61t main gear (on main shaft)

1/(22 ÷ 68) x (19 ÷ 61) = 9.92 (to 1)

Calculate motor RPM... if you're conservative use 3.3v per cell (minimum fully loaded voltage so HS could be higher but this will be sustainable HS).

For 6S pack and 1100Kv motor assuming 90% efficiency...
6 x 3.3v x 1100kv x 0.9 = 19602 RPM

Headspeed = 19602 ÷ 9.92 = 1976 (sustainable)

[ping]

Exactly what I needed thanks!

[Zoobie]

Hi guys, I am a little confused.

If I use the above formula I get a HS of 1889, but if I use the readyheli calc. I get 1540 (95% eff.) I have a 13T pinion then 42T and 61T and the gaui 1100kv. I want to slow things down a little to extend my flight times.

Thanks.

[bstock]

With 6s... I am coming up with 2354 HS at 0% drag - and 2119 at 10% drag. Use the 10% drag figure.