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Old Aug 06, 2003, 02:02 AM
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Which would you take: AXI 2820/10 or Mega 22/30/3

Hi all

I see quite a nos of folks using the outrunner for 10 cell sport or even warm/hotliner climb.

WHat about the Mega 22/30/3, is it able to deliver the same performance of the AXI?

Say 4lbs bird, 10 Sub C cell, 2m span.
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Old Aug 12, 2003, 10:34 AM
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Magna,

I'll let you know after tonight's flying session.. As a seasoned AXI 28/20/10 flyer, I'm about to try a mega 22/30/3.....

Regards,

Steve
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Old Aug 12, 2003, 01:08 PM
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I've never used the 2820/10 but I am flying a Bridi Warlord 20 (60oz, 444 sq inches) on a 22/30/3 on 10xsubC cells (10x2400, 10x2600) spinning a 10x5 APC E-prop - draws about 38A static. It flies quite nicely with this setup.

I had looked at getting a 2820/10 at one point while waiting for the Mega to be repaired (I crashed Warlord #1) but the main problem I had was that in order to get similar thrust (at least according to Motocalc) I had to go to a larger prop. And, I would have to sacrifice some pitch speed to get this thrust. This was supported to some extent by lots of posts where this motor is used with an 11" or 12"prop and 10 cells. I didn't want to make new landing gear for the plane (the 10" barely clears as it is) and I was a bit concerned about the lower pitch speed. So, I just waited for the Mega to be returned.

I look forward to Steve's report, though to see what his real world experience shows.


Mitch
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Old Aug 12, 2003, 03:22 PM
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Depends on the plane. It is not as simple as which is better.

The mega would be great for speed with a smaller prop. The AXI likes larger props and thrust.
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Old Sep 23, 2003, 07:54 PM
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Steve

Any report?
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Old Sep 23, 2003, 09:02 PM
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france
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i think it makes a big differance on the plane your using ,if its a glider then things change a lot ,if its a sport plane well,you get the idea,,im very interested in both theses motors becuase im putting together a 2.8 metre glider
i have heard that the axi is better suited for gliders becuase they run larger props and deliver more power [torque] which is better suited for gliders,however the wires exit the side of the motor which may cramp the fuze if the room is tight


viti
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Old Sep 23, 2003, 09:18 PM
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What is your AUW? I have a 2.8M glider Elipsoid which I have flew on Mega 30/3 with 8 RC2400 on 11x6. It climb well and fast but at a more shallow angle say 40degree? My AUW like 4.5lbs.

Then I geared the motor to 2:1 and using same batt pack on 14x9.5, it can climb at a more steeper angle but slower(figure!).

Then with 16x10, who-a, the climb is good and it just fly out of my hand.

With AXI, I don't think you can gear them, can you? If any one want a more thrust and lower amp, then 30/4 would prolly be a better choice.
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Old Sep 23, 2003, 09:53 PM
Florida Flyer
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I fly Axi's on my motorglider (Dynaflite Butterfly 99 in. WS) On direct drive 12X8 on 10 SC cells it rips up to 4-5 hundred feet in less than 30 sec. Go higher, shut down and glide. Flights last as long as I want. After 20-30 minutes it loose interest. Have a 2820/10 on my Magic Sport. Flight times are short, although loops rolls and vertical are fun. Have installed a gearbox 2:1 Inner demon with the AXI and will be using 14X10 prop. Motocalc promises 5-15 min flights depending on throttle useage. Will see when the 12x3300 batteries arrive.
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Old Sep 23, 2003, 10:04 PM
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I have this AXi on 10 cells and an 11-6 folder. It flies a 4 + lb pattern type pretty good. It will swing a much bigger prop but at a lower rpm.

I also have a Jeti 30-3 I flew the same plane with. It also swings a bigger prop and slower than the Mega. I think a 10-6 and ten cells was goot.

I bought a mega too. My understanding is that they will hold up under extended high revs (like over 15,000) better than the Jeti, which mine (the Jeti) did throw a magnet on 16 cells and a belt reduction, but was repaired and kevlar wrapped and still works most satisfactorily.

I think the AXI is the most efficient but would top out at 350 watts or so. You can get much more from the Jeti and Mega more still. probably approaching a full horsepower at 16 cells, and the Mega has an open can for better cooling.

There was an excellent article here on the Zone with tables that compared the Mega22-30-3 and the Jeti, with cell counts and prop sizes, which would suggest the Jeti was a little more efficient.

Geez, I think you could gear the AXI too. like with a MPJET planetary and a really big prop, but would be sailplane stuff.

I flew a 40 sized Aeronca Champ with the Jeti and the Modelairetech belt drive. It flew very well, a proverbial big air flyer, and lasted over 5 minutes on 16 3000 nimh
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Old Sep 24, 2003, 07:25 AM
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france
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Quote:
Originally posted by Magna
What is your AUW? I have a 2.8M glider Elipsoid which I have flew on Mega 30/3 with 8 RC2400 on 11x6. It climb well and fast but at a more shallow angle say 40degree? My AUW like 4.5lbs.

Then I geared the motor to 2:1 and using same batt pack on 14x9.5, it can climb at a more steeper angle but slower(figure!).

Then with 16x10, who-a, the climb is good and it just fly out of my hand.

With AXI, I don't think you can gear them, can you? If any one want a more thrust and lower amp, then 30/4 would prolly be a better choice.
im interested in your results,my auw is about 4.5 also in a www.soboxplanes.com harpia 2.8
i was looking at the 22/30/2 mega becuase they say its better suited for 7/8 cells ,the chart i read suggested 10-12 cells for yours [i dont know]
i was planning on running a 10/6 or 11/7 folder on several differant packs

7xrc2400 sub-c
8xcp1700
7xcp 1300

i know what you mean about climbing steeper but slower with the gears ,i built two hobby lobby skimmers ,one geared ,one not and thats the main differance,i prefer to cover more ground while climbing with the faster airspeed

however im left wondering if i should go with the 22/30/3 is there an advantage with that over the 22/30/2? i do not wish to run more than 8 cells however becuase im converting a glider to electrics and my space is limited

also you said it flew nice with the 16/10 but didnt mention what cells or how many please advise you will notice your glider is a very close comparison to mine so that would explain my interest TIA viti
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Old Sep 24, 2003, 08:03 AM
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Seems to me you want altitude, not speed with your glider unless you have a highliner. A 2.8m glider does not sound like a highliner.
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Old Sep 24, 2003, 08:19 AM
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At last!

Sorry for the delay chaps,

Having flown my Mustprang, and 45" Tucano (AUW 3lb) extensively with both AXI 2820/10 and Mega 22/30/3, I'll never buy another AXI!

The mega is more responsive, quieter,both in terms noise and EMI (NO Glitches!!) and is rated to 70A where the AXI can realistically take 40A. Also there are some issues with the AXI by way of loose magnets, poor balance causing firewall delamination....If you can live with a prop change from 11*7 to 10*7 and increased RPM, then the Mega surely is the way to go...

Regards,

Steve
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Old Sep 24, 2003, 11:53 AM
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france
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Quote:
Originally posted by dimberio
Seems to me you want altitude, not speed with your glider unless you have a highliner. A 2.8m glider does not sound like a highliner.
sorry ,i should have explained better,a geared setup will climb steeper with less airspeed,more thrust but a non geared [mega] seems to not climb as steep but create more lift from the wing with more airspeed,both seem to arrive at the same height or there abouts in about the same time frame,i just like to get up-wind more with the non geared set-up but yes you are right,its height i want for thermal duration

the hobby lobby skimmer is a classic example,it climbs great with a bit of speed rather than relying on the geared prop to lumber it up

just an observation cheers viti
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Old Sep 26, 2003, 04:24 AM
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Hi Viti

Sorry my for delay. All my setup above using 8 RC2400 packs. Both direct/geared and from 11x6 to 14x9.5 and 16x10.

With 10 cell pack RC1700 geared and 14x9.5, it climb really fast, going vertically actually although limited.

With geared, you will get lower prop speed but with the thrust generated it will out climb a direct smaller prop(generally) for a steeper angle. Also glider(not hot/warmliner) have a slower top speed so the excessive speed generated by the small prop with direct are wasted because for glider climb and glide, you want thrust at a reasonable speed. Tonnes of thrust at speed below your plane stall speed do no good either.

Say with geared, I can climb with 65 degree but the direct the most at 40, so the geared take a shorter route at steeper angle but slower airspeed vs the direct at longer route with shallow angle to the same height.

So on your 2.8M, if you prefer no more than 8 cell, and great climb, you won't go wrong with mega 22/30/3 2:1 and 16x10 folder. For even more power, Mega 22/30/2 will really hauls it up fast albeit at higher amp.

Though the direct setup can climb fast at less angle and prolly reach the same height as geared, but it is lesser efficient because the geared setup in the above uses less Amp for similar climb, so I get longer run time, and cooler motor/batt! And lonngggg flight time.

Of course there are better system out there but for bang/buck ratio, the mega is unbeatable.

BTW, for fun, I have belt driven this mega 22/30/3 on 16 rc2400 with 14x6 to fly a 7.5lbs cub. It fly for 12 mins!
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Old Sep 26, 2003, 04:26 AM
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Steve

Thanks for the info. But it still seem a lot of folks out there using the AXI, though it depends on your flight style but the mega is more versatile with higher amp and robustness!
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