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Aerial Photography and Video > 20 pound electric, with 15 minute flights?
 
 
papatango
Senior Heliman
Location: Toronto, Ontario, Canada

Pawned this from the "E-conversion" threads:


NEU 2215/3Y with 8mm Shaft
480 RPM/Volt
5000 watts
5000 / 746 watts per Horsepower = 6.7 Horsepower

Castle Creations 110 amp ESC

2 parallel R/C Model Works UberBEC’s up to 55 volt supply 5 volt output at 4.5 Amps = 9 Amps at 5 volts

12s1P LiPoly – 44.4 volts 4900 mAH
2 EVO 4900 Trex packs in series

Lower Ratio (Belt)
14 tooth pulley (.200 XL)
40 tooth pulley (stock Vario)
= 2.857:1
Upper Gear ratio 5:1
2.857 X 5 = 14.285:1

44.4 volts Nominal X 480 rpm / volt = 21,312 motor RPM
21,312 / 14.285 = 1,491 RPM head speed (usually run 1450)

44.4 volts X 4.9 AH = 217.56 watt hours
217.56 watt hours X 60 = 13,054 watt minutes

The helicopter hovers on about 50 watts per pound
harder flying averages about 65 watts per pound

19.8 LBS X 50 = 990 watts
19.8 LBS X 65 = 1287 watts (10 minutes = 12,870 watt minutes)
I usually fly 9 Min some mellow and some hard
uses about 80% of the pack

The system is wired for a parallel bank of batteries (totaling 4 EVO 4900’s arranged 12s2p 9.8AH @44.4 volts). This will push the flight times to ~15 minutes.



After hearing about some of the short flight times in the AP forum, are 15-20 minute flight times easily achievable??

The last thing I heard my ex say: " It's either me or that damn Helicopter"......
09-29-2008 01:32 AM
HOMEPAGE  
 
 
gjestico
Senior Heliman
Location: Vancouver, B.C.

Quote 
The system is wired for a parallel bank of batteries (totaling 4 EVO 4900’s arranged 12s2p 9.8AH @44.4 volts). This will push the flight times to ~15 minutes.


That is about 6.5 Lbs of batteries. $1200 worth for one flight. Looks like this is a Joker ? not a lot of room for payload before you hit the 20 lb mark. Whats a maxi joker weigh sans batts ?
09-29-2008 04:17 AM
HOMEPAGE  
 
 
Heli 770
Elite Veteran
Location: Lemon Grove, Ca. USA.

There was as Airwolf with a Vario in it built almost the same as papatango described on his setup.
09-29-2008 04:30 AM
 
 
trackhead
Key Veteran
Location: utah

Why do you want 15 minute flight times?

I find 8 minutes is usually more than enough for any filming scenario.
09-29-2008 05:04 AM
 
 
fionn
Heliman
Location: Ireland

Duration

I've achieved 20mins + on a maxi running 800's and 12S 6000Mah packs with gentle flying and not carrying much weight. 15mins carrying a camera and mount (+2kg or so) is no problem.
This is without much / any reserve though.
09-29-2008 10:31 AM
 
 
papatango
Senior Heliman
Location: Toronto, Ontario, Canada

770,
This is not my setup. Read the first line of my post, it's the Airwolf Vario set up.

Track,
I've been asked to do some filming that will require extended flight times, with a 6-7lb payload of gps instruments & thermographic cameras.

The requirement is for an electric heli, I'd prefer not to set up a gasser for this.

I require a 15 minute flight envelope, with two minute reserve, auto capability; with a six pound payload.

Sounds like some tough demands, but the bar has been set pretty high by a client, and I'd like to deliver.

Thoughts? Set up suggestions?

The last thing I heard my ex say: " It's either me or that damn Helicopter"......
09-29-2008 01:02 PM
HOMEPAGE  
 
 
Heli 770
Elite Veteran
Location: Lemon Grove, Ca. USA.

papatango
Thanks for the clarification. I don't know if this will help you but now you can use up to 90volts and 200amps with the SHV-ESCs.
09-29-2008 01:18 PM
 
 
AirFoilAviation
Veteran
Location: IL.

This may or may not help and is not a sale pitch but a hope for more posting. We havebeen and are flying a JR GSR like on our site but we talked JR into packaging it dedicated to electric because there are times when you need electric but it also makes life easier on some flights.

With that said we compared numbers to other new 800mm ships on the market.

Check these number.
The heli RTF with 10s 6000mah pro lite packs. A set we sell for $389.00 for two pack to run in series, with a AUW of 12lbs with flight batteries.

This is the same strength and specs. as the GSR just converted to electric.

We run a 259kv motor then machine an aluminum pinion for a ratio of 5.5.

What blew us away is with the Pro1/KS2 gyro/HC1 HD camcorder we were at 9lbs. payload which the heli lifts like nothing. Our timer is set on 15 minutes and runs on 70% throttle.

If you own a GSR the conversion with motor/pinion/esc/ mounting bracket with series connectors would be $549.00.

If you don't the GSRE with blades and the kit above would be $1649.00 plus $389.00 for a battery set so you have a total of $2038.00 in a heli that can lift 10lbs. for 15 minutes with the strenght of a gasser heli.

This was our goal it's simple and flying.

We also have the T-Rex 700 flying for 15 minutes plus carrying 7lbs. of payload with the same batteries listed above. You will see more on the web site as I'm trying to setup an R&D page to show what's in the works from the 4 stroke gas to the GSRE.

Food for thought.

John

Team AirFoil
09-29-2008 02:31 PM
 
 
trackhead
Key Veteran
Location: utah

Quote 
We also have the T-Rex 700 flying for 15 minutes plus carrying 7lbs. of payload with the same batteries listed above.

How are you doing that?
09-29-2008 04:53 PM
 
 
fcbmunfan
New Heliman
Location: USA

This is not a sale pitch ????
09-29-2008 05:07 PM
 
 
AirFoilAviation
Veteran
Location: IL.

Trackhead as probably 20 people or so on here know we had at one time sold the Voyager 50 and then stretched it to accept 680-710mm blades. Several purchased the heli before JR changed to the Airskipper.

We tested lots of gear ratios in this weight which is important along with motors also important. We found a motor/esc/ratio combo that would let us lift 7lbs. payload at 20 amps. running the motor at 75-80% power. We are able to run on 10 cells to keep the weight down and found with the low amp's needed you could fly 6000mah pack to 3.1 volts and stay in the air safe for 15 minutes with reserve.

John

Team AirFoil
09-29-2008 05:26 PM
 
 
papatango
Senior Heliman
Location: Toronto, Ontario, Canada

John, I'd like to hear more about the 700.

.... and I know it's hard not to have your post sound like a sales pitch, so I appreciate your input. If it were an unsolicited post, you'd hear about it; but, since I've asked, and you've offered some great input, feel free to elaborate.

Thanks,

Patrick

The last thing I heard my ex say: " It's either me or that damn Helicopter"......
09-29-2008 05:26 PM
HOMEPAGE  
 
 
rerazor
Elite Veteran
Location: Mich.

Wouldn't running close to 100% be more efficent?

What motor and esc are you using?
Motor temps?
09-29-2008 06:03 PM
 
 
tabbytabb
Elite Veteran
Location: seattle

15 minute flight should be doable with a 12s6000-7500mah lipo on a 800 size ship running 1300 or lower on the head.


I can fly 8 to 10 minutes on 12s5000mah packs at 20lbs AUW (12lb heli, 8lb payload) with plenty of reserve in the pack.

I dont like to drag my packs down more then 50 to 60% though so they last a long time.

Tabb
09-29-2008 06:10 PM
HOMEPAGE  
 
 
ministock22
Senior Heliman
Location: Newcastle, OK

Is it bad on your batteries to do a short flight, then charge them fully again? I have heard some say something about a memory your batteries will get, is this true? Kind of goes along with what Tabby just said, but now I'm confused.

Thanks
Denny
09-29-2008 08:23 PM
 
 
fionn
Heliman
Location: Ireland

Memory

Memory effect only applies to NiCad batteries and AFAIK the evidence for it's effects was questionable in the first place. Somehow it made it's way into popular culture and now a lot of people believe in it for all batteries. To the best of my knowledge the number of life cycles you will get from your LiPos is inversely proportional to the depth of discharge, that is, top them up when you can
09-29-2008 08:35 PM
 
 
ministock22
Senior Heliman
Location: Newcastle, OK

Awesome thanks fionn, I have heard this before and it has always been hard for me to believe this, but I have seen crazier things.

Thanks
Denny
09-29-2008 08:52 PM
 
 
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Aerial Photography and Video > 20 pound electric, with 15 minute flights?
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