E7 with 12s

[devilfish]

Hello from Sweden

I have just sold a F3C heli ( rave ), and got alot of nice 6s 5000mAh lipos over, as well as a jive 120hv.
I would like to use those lipos and the jive 120hv on the E7.

Is 5000mAh 12s going to be to heavy for the E7?

My flying style is more sport, big manoeuvre 3D etc.

I also wounder what motor/pinion you should recomend for a 12s 5000mAh E7.
My plan is to keep the rpm around 2000rpm for my flying.

Thanks!

[seldred]

I have two 6 s 5000 mah packs for my e7 an I fly 3d. It performs well, but would like a lighter weight. For your type of flying you should be fine with what you have. I have a pyro 700 45L for a motor and a 13t pinion. I'm not sure if Matt has that pinion available yet. If not I would think it will be soon.

Regards,
-Steve

[devilfish]

Thanks

With the pinions that come with the kit, 14/15, what motor would work with those?

Cheers

[churchyj]

Sure a 14 would work but with a 14 tooth pinion at 90% peak power the HS might be a little high. Lets have a look at the old HS Calc, these specs are based on different C battery ratings but all 14 tooth pinons and 12S Configs:

Result for calculation: 35C 12S
Estimated lowest voltage during flight: 40,92
Lowest RPM (due to voltage and efficiency) : 2000

For + performance, keep req. RPM below: 2070
For target performance, keep req. RPM below: 2153
For - performance, keep req. RPM below: 2215

hmmmm looks pretty good actually, lets have a look at 45C

Result for calculation: 45C 12S
Estimated lowest voltage during flight: 41,76
Lowest RPM (due to voltage and efficiency) : 2041

For + performance, keep req. RPM below: 2112
For target performance, keep req. RPM below: 2196
For - performance, keep req. RPM below: 2260

Yep that looks o.k indeed, 14T is a goer with that motor. Lets have a look at a 65C setup just encase.

Result for calculation:
Estimated lowest voltage during flight: 42,48
Lowest RPM (due to voltage and efficiency) : 2076

For + performance, keep req. RPM below: 2149
For target performance, keep req. RPM below: 2235
For - performance, keep req. RPM below: 2299

Bang on I recon.  Now all these stats are based on a governed motor i.e. using a v-bar or ESC gov, the HS will be much higher in each senario if the motor is not governed which I personally would not recommend.

Regards,

Justin

[seldred]

Justin beat me to it. @Devilfish, I was going to use the same method to answer your question. The head speed calculator is a great tool to have! If you have not found it yet, you can find this at readyheli.com in the bottom left of the page. Here is a link for it: http://www.readyheli.com/headspeed-calculator.html

Simply plug in the specs of your model, and hit calculate!

Best Regards,
-Steve

[devilfish]

Thanks for the help

Now I must just find a EU retailer that stock the E7

[devilfish]

Also I noticed that the JIVE gov works best with alot of headroom. So 60-65% in gov mode4 has worked perfekt before..

cheers

another thing, do I need the Kontronik Brushless Motor PYRO 700-45 long shaft or the "normal" one?

[seldred]

I'm using the pyro 700 45L. (long shaft)