Converting a Vario Skyfox to brushless, what can I expect (e.g. amp draw)

[Silence]

Hello everyone,

this is my first post here, have been on RC Groups for over 6 years. My first helicopter was an Ikarus Eco Piccolo (bought in 2002) and since then I've been growing towards where I wanted to go: BIG helicopters

So now I've bought a Vario Silence. It's actually a Vario Skyfox with a motormount for an electric motor and side supports for those big ol' NiCd or NiMH's. I've already done A LOT of researching so far but I keep struggling with the following:

I already have a Kontronik Jazz and I've hosen for a Scorpion 4035-560. This setup has been done before in a Sky Fox. However, I just can't seem to find out how many amps this will pull. From other sources I've seen 18-20 minutes flight time using a 10S2P 4800 mA konion battery (current Silence) and 12 minutes with a 4000 mA lipo batt (converted Sky Fox with Tango motor). Both therefore draw about 12-16 amps on average. Can I expect such currents with a Scorpion 4035-560 motor ?? Io seems one amp higher than the more efficient Tango.
This is really important to me regarding choice of battery.

Also is the following theory right?
When other comparable helicopters draw 12-16 amps, my helicopter with a slightly different motor would approximately draws the same? If so, I only need a battery that is able to discharge 55A continious (due to Jazz 55 ESC)?

I've also read many threads over the internet of helicopters that use a Scorpion 4035-560 and draw about 80 (!) amps They usually say they fly with a headspeed of 2000-2100 RPM. I intend to fly within Vario's recommended headspeeds. That's 1600 max. I wish to fly at about 1300 RPM. I guess a lower amp draw can be expected because of the much lower headspeed.

Thanks in advance for cracking this nut!

Dave

[bmichels]

Originally Posted by Silence

From other sources I've seen 18-20 minutes flight time using a 10S2P 4800 mA konion battery (current Silence)

Dave

I am like you very intereted in finding infos on the SILENCE from vario. There are not much out there. Many people are looking at other manufacturer for Large Electric (Logo 24...). I still believe the SILENCE is a very interesting route to follow for my "small" Airwolf project.

Could you tell me where you read that 18-20 minutes flight time can be achieved with only 4800 mA ? Do you remember what motor was used ? What was the weight of the Heli ?
--> Do you have the link to the thread or to tests/reviews of the SILENCE?


thanks in advance

[Silence]

You might want to check my blog http://www.rcgroups.com/forums/member.php?u=24877
Also, the other site is: www.graf-eckstein.de

My project is slowly progressing. Just bought a new charger and 2x 5S1P 5.000mA Zippy Flightpower batteries. Only thing that's left is to order the brushless motor.

Too bad noone could help me

[bmichels]

Very very interesting infos on www.graf-eckstein.de
THANKS a lot

but... are you sure that the Scorpio motor will offer you better duration than the original VARIO Offer: TANGO 45-04 ??

The guy on Graf-eckstein says that he has 17-20 minutes flight with the Tango and some "small" lipos 10s-4800 mA !

If it is true, then the scorpio is not a better solution if you are looking (like me) at max flight duration ?

[Silence]

Yes, you are right. The Tango is of better quality. There's a large "but" about this though, the price of the motor hasn't decreased ever since it was released. Sure, it's worth the money but usually prices decrease.
I bought a second hand Kontronik Jazz 55A speed controller for about 120€. The Scorpion motor costs about 140€. The recommended set that Vario lists at their webshop is 500€ +. This means that the set that I have is about half the price..
Also, if you had looked on my weblog you'd see that my Vario Silence is based on the Skyfox series. Because I have a wider frame I can fit a wider motor. The Scorpion motor fits in my heli, but not in the current Vario Silence.
If you go for the current Silence and not for a Skyfox conversion, there's not much left for you to choose than the Kontronik set.

[bmichels]

What is the address of your web blog ? I can't see it !

[Silence]

It's in post #3

[Silence]

Hi all,

Long while since posting. Really because I have flown it a handful of times since posting!

Set up is a Scorpion 4035-560 with a gear ratio of 7.86:1 (first stage 55/28=1.96. Second stage 40/10=4). I have a Kontronik Jive 60a HV controller, and two 5S 3700mA lipos. A GY-520 controls the tail, all servos are DS821.

Set up is as per Vario recommendation. Throttle curve is 20% flat (governor) in stunt 1 and 45 in stunt 2.

Today I flew on 5S, since I was impatient and I had forgotten my harness to connect the batteries in series!
Flew at 45% governor and weight of two batteries. It actually went up, flew a circuit. After some minutes I landed, connected the fresh battery and removed the used one (saves 425 grams). Center of gravity was ok.

Second flight on 5s, governor up to 85 percent. Flew wonderfully, floaty, too. I didn't dare to give full pitch since I was clueless about amps. The system (batt, motor and ESC felt warm. Though still lukewarm).
As with the first flight, smooth circuits only. Some hovering in ground effect, 15kts wind, about 14 degrees Celsius.

Now the "data":
First flight 1070mA charged. 19.7V left.

Second flight 1468mA charged, 19.4V left. 7,5 minutes flown. Average 195 mA/ minute.


What do you guys think? I'm happy but I'm also thinking about getting a Logo 600. All undecided still!