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View Full Version : Using 3 cell 340mah Lipos with Axi 2208/34?


hillbilly808
10-18-2005, 01:43 PM
Hi, I was wondering if anyone has tried the Axi 2208/34 with 3 cells 340mah lipos on a shock flyer?
If so, what size prop did you use?

Thanks
Jon

fdix
10-18-2005, 03:48 PM
With an APC slowfly 9x3,8 you have 9,1A and 550g static thrust on 3s lipo. I would use 700mAh cells.. the 340's are a bit small, or go with a smaller lighter motor.

Matt Kirsch
10-19-2005, 01:13 PM
You could always go with a smaller prop, say, an 8x3.8. That'd bring the current down into the working realm of Kokam 340s. There's a little power lost, but that's more than offset by the amount of weight saved.

Check out www.modelmotors.cz (http://www.modelmotors.cz) for the manufacturer's test data on this motor. They've got a pretty comprehensive chart on what this motor will do with various batteries and props. I can't remember if they have specific LiPoly numbers or not, but if they don't, use 7 NiMH as the equivalent of a 2S LiPoly, and 10 NiMH as the equivalent of a 3S LiPoly.

hoppy
10-20-2005, 12:47 AM
Try this site for motor data-
http://www.flyingmodels.org/motortest/Link_e.htm

7x4 APC SF?

hillbilly808
10-20-2005, 01:15 AM
Thanks for your help, much appreciated. That web site is great lots of info.
Cheers

Dr Kiwi
10-20-2005, 05:02 AM
To get the current down well below 7A, 'cos that's probably more than those 340's can deliver at decent voltage, you may need to drop down to 7x3.5 (an 8x4 GWS HD pulls over 7A and a 7x4 APC SF won't pull much less). I'd forget those wimpy Kokams and get at least TP Prolite 480's or 700's (do they make those?) - then you CAN use a decent sized prop and draw the 8A max the motor is rated for.

fdix
10-20-2005, 12:46 PM
With a pack of epower EP450HP you can go to 9A. With the EP700HP's 12A.

Mike Wizynajtys
10-20-2005, 01:24 PM
I'd forget those wimpy Kokams and get at least TP Prolite 480's or 700's (do they make those?) - then you CAN use a decent sized prop and draw the 8A max the motor is rated for.

They (Thunder Power) make 860s, and I really like 'em. I also like my Appoge 830s. They are both great. I have some Kokam 340 and they are week. I have a pair of TP 480 which are better, but I think that are a little too week for my liking as well.....and the duration is too short if you do much hovering.

I guess everything is a trade off. I'll take the little extra weight of the 800ish size cells along with their extra duration and current handling abilities over the tiny 400ish size cells any day.

Wiz

Matt Kirsch
10-20-2005, 01:33 PM
Hmm, I've got my Shocky Yak/PJS300SF combo propped to draw 8.1 Amps at full steam, running a 3S pack of Kokam 340s, but of course, I limit full throttle pulls to 1-2 seconds, and most of the time is spent with the stick in the lower half of the quadrant. They've got plenty of punch, and barely get warm to the touch. Granted, I don't have 15-minute flights, but since going to larger packs would increase my Shocky's weight by 15-20%, I can live with 5-7 minutes and the flying qualities I've got now.

Greg Covey
10-22-2005, 03:45 PM
Light ‘n Heavy 3D Setups:

Just when you think your 3D setup is totally hopped up with the lightest components and building techniques, along comes another product that makes you want to start all over again. It is a feeling that we have all had at one time or another. The constant bombardment of new R/C products has us nearly crazed! We’ll take a look at some of these newer products and try to simplify the choices into a few categories that we found very helpful during our indoor flying season last winter.

There have been many new smaller brushless outrunner motors introduced to R/Cers in the last year. We tested several of them during our indoor flying season last winter and arrived at two categories; light and heavy. While the lighter power systems fly better indoors, the overwhelming power of the heavier category has advantages when flying outdoors. Many of us built both lighter and less rugged 3D planes for indoor flying as well as heavier and sturdier versions for outdoor flying with a little wind.



Several motors fell into our “light” category. Motors like the LensRC 17t, AXI 2204/54, Esskay 300XT, and Python 30 could provide about 10oz of thrust with an 8x4 prop and 2-cell Lithium pack. Any plane in the 5-7oz range equipped with one of these setups had plenty of power for 3D maneuvers.



The heavier motors like the AXI 2208/34, Nippy Black 0808, Esskay 400XT, and Python 60 had tremendous power levels at the cost of increased current and additional weight. These power systems typically added about 3oz to the setup due to the heavier motor and battery, which could easily be felt during maneuvers when flying indoors without any wind.
Our initial Shock Flyers weighed from 7oz to 9oz. These planes flew amazingly well both indoors and outdoors in a light breeze. We then discovered that newer and smaller motors like the AXI 2204, Python 30, Esskay 300XT, and LensRC 17t may have provided less power, but, the lighter weight still allowed for a 2:1 thrust to weight ratio. In other words, since our re-built Shock Flyers now weighed only around 5.5oz, the 10oz of thrust provided by these tiny motors was more than enough for good 3D maneuvers.

Here are a few of the setups we tested:
Shock Flyer Setups


Lighter Setup (5.5oz)
LensRC 17t
Jeti 4-amp ESC
2-cell Kokam 340mah pack
GWS R4-P or FMA M5 receiver
GWS Pico BB or FMA PS20 servos
APC 8x3.8 SF prop
Heavier Setup (8.5oz)
AXI 2208/34
Jeti 8-amp ESC
2s2p Kokam 340mah pack
or 2-cell 860mAh ThunderPower pack
FMA M5 receiver
Hitec HS-55 servos
APC 9x6 SF prop Tensor 4D Setups


Lighter Setup (7.0oz)
AXI 2204/54
Jeti 4-amp ESC
2-cell Kokam 340mah pack
FMA M5 receiver
FMA PS20 servos
APC 8x3.8 SF prop
Heavier Setup (10.0oz)
Esskay 400XT
Jeti 8-amp ESC
2-cell or 3-cell Kokam 640mah pack
or 900mAh ThunderPower pack
FMA M5 receiver
HS-55 servos
APC 9x6 SF prop The introduction of many new brushless outrunner motors can be simplified by sorting them into a few weight and power output categories. The result leaves us with a personal preference choice on price, color, and, ease of mounting. Sometimes, the price can be directly related to the product quality, but, this is usually only seen on the extremes of each range. For the most part, the price drop from competition of so many products and manufacturers makes the electric flight enthusiast the real winner!

Mike Wizynajtys
10-22-2005, 04:11 PM
Hmm, I've got my Shocky Yak/PJS300SF combo propped to draw 8.1 Amps at full steam, running a 3S pack of Kokam 340s, but of course, I limit full throttle pulls to 1-2 seconds, and most of the time is spent with the stick in the lower half of the quadrant. They've got plenty of punch, and barely get warm to the touch. Granted, I don't have 15-minute flights, but since going to larger packs would increase my Shocky's weight by 15-20%, I can live with 5-7 minutes and the flying qualities I've got now.

I'm sure that combo flys well, Matt. I've flown similar and been fairly happy with it. Still, I like my 2 cell 800ish systems better. Really we are just disscussing personal preference. I'll probably put together another really light weight airframe for indoor pattern type flying sometime in the next couple of weeks. With that plane I'll want to use the smaller cells. For just 3Ding around I like the bigger ones and a little more robust airframe. It just lasts longer. ;)

Matt Kirsch
10-22-2005, 05:26 PM
Personal preference has a LOT to do with it, that's for sure.

Right now I'm chomping at the bit to test fly my latest Shocky, "Budget Bird." It's a ShockFlyer Nemesis ($20 from Hobby Lobby), powered by a 3S Kokam 340 out of my personal stash ($30 at Tower), Potensky 50W with the stock 8x4 folding prop ($30 in HL's Thanksgiving in July Sale), Great Planes SS8 ($30 at the LHS) and leftover GWS Pico gear. Total AUW is 6.0 ounces even. I used all the stock carbon, and even added surface area to the ailerons and rudder to make the plane more 3D :)

Greg Covey
10-22-2005, 09:36 PM
Matt,

Keep an eye on the new indoor dates. The first one may be pushed out a week but the RIT event is set.

http://www.gregcovey.com/events.htm