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Old Jan 25, 2009, 04:00 PM
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By Gad, ditchit, that Spear is moving. Gotta get myself one of those data loggers! So true how a picture (er, ok, graph in this case) explains thousand words!
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Old Jan 25, 2009, 04:03 PM
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Quote:
Originally Posted by Jacques.Eloff
Useful thread this is Ė exactly the info Iím looking for!

My experience for anyone interested: I was not content with 700W on my Lander F-9 Panther with HET Typhoon 2W-20 on 4S (6904 fan). In my quest for a good 6S setup, I decided to try the 3W-25. According to the HET motors spec sheet, it has the same power rating and max amps as the 2W-25 (1100W, 50A) but it has a much lower KV (1700 vs 2660). This is strange because 6S is recommended for both motors Anyway, the dealer did not have a 2W-25 in stock, so I went with the 3W-25 (impulse buy).

Well...let me say that this is NOT the option for 6S - I only managed to get a paltry 720W, and that was using 2 x Zippy Rhino 3700mAh 3S packs, which hold their voltage very well. Sure, current draw was pleasingly low at 31A, but Iím really after 1KW+.

Now, let me say at this point that the 3W-25 was not necessarily a bad purchase and I am not slamming HET motors in any way: I recently read on this forum that the 3W-25 (and 4W-25) actually need more than the recommended 6S, which stands to reason considering their much lower KV ratings. So, I decided to try 8S (using 2 x Flightpower 4S 2150mAh 20C packs). This gave me 1010W at 40A. Still, I expected more, so did another test using 2 x Polyquest 4S 3200mAh 30C packs, which gave me 1060W at 42A. I would not actually be able to fly with this heavy setup; just wanted to make sure the battery capacity was not the bottleneck.

So at this point, Iím thinking that I will settle for 2 x Flightpower 4S 2150mAh 20C packs, giving me 1010W at 40A. The resultant loaded voltage of 25.3V is evidence of voltage sagging, but Iím still under 20C at WOT, so I reckon it will be OK with some throttle management.

In the meantime, I had ordered a pair of ďOverlanderĒ 4S 2200mAh 35C packs for another EDF model. Iíd never actually heard of this brand, but they seem to have some favourable reviews (hmmÖimpulse buy again). WHOOHAAA suddenly Iím getting 1480W at 53A! Scarey! Again, this reinforces the importance of good packs that can sustain voltage under high load. Iím now thinking the 3W-25 is actually best for 7S, but Iím still dumbfounded as to how these 2200mAh 35C packs can outperform Polyquest 3200mAh 30C packs. Anyway, Iíll be ordering a pair of 3S 2200mAh Overlander packs tomorrow, so that I can test 7S.

Will this be the sweetspot for the 3W-25? Or perhaps I should try a 2W-25 or Mega 16/25/2 on 6S as suggested earlier in this thread. Any opinion/advice welcome...

Really enjoying learning first hand about this EDF stuff...


3W-25 KV is 1700
2W-25 KV is 2660
on 6S lipo, there is a big difference between the two systems

I am not an expert, just a hobbyist who
wants his hard earned money well spent.

I had that light 6S power set up on my HL F-5E.
The max speed is about 100mph but
the straight up vertical is very nice, as long as I
can hold my breath. I am not that stupid to expect
that draggy F-5E jet to go like a bullet though.



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Old Jan 25, 2009, 04:26 PM
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Quote:
Originally Posted by krashfree
3W-25 KV is 1700
2W-25 KV is 2660
on 6S lipo, there is a big difference between the two systems

I am not an expert, just a hobbyist who
wants his hard earned money well spent.

I had that light 6S power set up on my HL F-5E.
The max speed is about 100mph but
the straight up vertical is very nice, as long as I
can hold my breath. I am not that stupid to expect
that draggy F-5E jet to go like a bullet though.



Absolutely, krashfree, my very point! Strange that the manufacturer could specify 6S for both motors, considering the vastly different KV ratings. And that's not to mention the 4W-25 which is even lower, at 1280KV. Perhaps the 3W and 4W motors are actually meant for prop, rather than EDF.

Ditchit - I see the manufaturers warn against extended WOT on 5S, 2W-23 combo. You are running 6S - have you not had any problems?
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Old Jan 26, 2009, 01:36 AM
DominicM
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Fleet, Hampshire, UK.
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No problems with the motor over about 15 flights in that setup Jacques BUT the Spear is not your typical EDF model. It's all about short sharp max throttle use on downwind high speed passes. You can see on the graph that on the alternating upwind passes I run maybe 50% throttle. And when I land I typically do one descending circuit and one circuit to slow down, flick up the elevons for finals. If I was WOT most of the time I doubt it would last long.

Ultimatley I'm using the 2W23 and the 6 cell packs because that's what I have. Like you I don't want to invest in a setup that MIGHT get me the 1.4KW+ performance I want, so I've waited and considered my options and only just ordered the Hoffman Magnetics Wild Beast from Foamyjets here in the UK. There's no firm option in motors for 1.4KW+ on a 28mm motor on 6 cells. That's apparent from the responses to this thread. I just happened to have the 2W23 lying around from another project.
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Old Jan 26, 2009, 03:11 PM
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Ouch! Just realised that my latest impulse buy was a c*ck up! I went with Maho's suggestion for Mega 16/25/2, but after placing my order, I was reading around on this forum and all I heard about was people using 4S with this motor. Then I read about the "FAI" version of the 16/25/2, which takes up to 6S . My fault! Perhaps I should do further research before ordering

Anyway, I'm sure I will have use for mine 4S version on my Lander F-9 or Starmax F-5 (on 4S) .

Still keen to try the 2W-25!
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Old Jan 26, 2009, 03:21 PM
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Quote:
Originally Posted by Jacques.Eloff
Ouch! Just realised that my latest impulse buy was a c*ck up! I went with Maho's suggestion for Mega 16/25/2, but after placing my order, I was reading around on this forum and all I heard about was people using 4S with this motor. Then I read about the "FAI" version of the 16/25/2, which takes up to 6S . My fault, perhaps I should do further research before ordering

Anyway, I'm sure I will have use for mine 4S version on my Lander F-9 or Starmax F-5 (on 4S) .
I would think that motor would be fine on 6s in the minifan. It definately woudl be pushing it. I've read of great success with it on 5s.
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Old Jan 26, 2009, 03:52 PM
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Quote:
Originally Posted by Jacques.Eloff
Ouch! Just realised that my latest impulse buy was a c*ck up! I went with Maho's suggestion for Mega 16/25/2, but after placing my order, I was reading around on this forum and all I heard about was people using 4S with this motor. Then I read about the "FAI" version of the 16/25/2, which takes up to 6S . My fault! Perhaps I should do further research before ordering

Anyway, I'm sure I will have use for mine 4S version on my Lander F-9 or Starmax F-5 (on 4S) .

Still keen to try the 2W-25!

2W-25 is about the same as 16/25/2, more or less.
2W-25 is cheaper, a little bit less efficient than 16/25/2 but
that is what you pay for. When use 6s on minifan with either
motor, do use good heasink and throttle control, not WOT for safety's sake.
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Old Jan 26, 2009, 04:59 PM
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Thanks for the comments and advice Gents! Since the 2W-25 and Mega 16/25/2 have similar KV ratings, then presumably there's not much difference, as krashfree points out. I guess I'm just conscious of the fact that the specs I've read for the Mega 16/25/2 suggest 4S/5S, whereas HET recomend 6S for the 2W-25. Perhaps this simply reflects more caution taken by HET when rating their products.

I'm now thinking ordering a 2S 2200mAh 35C pack to allow me to try 5S for the Mega. Clearly, I'm having fun playing around with various combos. Also, my Lander F-9 Panther is a bit of a porker on 8S 2200mAh (and 3W-25), she would love to shed a few grams! Maybe I'll even find the "sweet spot" for My H-L/Starmax F-5 with this.

I'm still wondering if there might be a difference between the Mega "FAI" 16/25/2 and the one I've ordered. The link below notes 6S for the "FAI" and the colour is also different to mine:

http://www.alex-rc-corner.de/epages/...s/Motoren/Mega

This is what I have ordered:
http://www.puffinmodels.com/category.php?dept=178

Jacques
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Old Jan 26, 2009, 06:01 PM
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Just an FYI, I have smoked two 2w-25s in HET fans on 6s. This is with 150-200 flights. The HET fan does draw a little more than the mini fan though.
It shows that the motor is running at its limits.
dc
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Old Jan 26, 2009, 06:52 PM
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The MEGA fai has stronger magnets and windings. MEGA rates it at 50 amps where the 16/25/2 is rated at 40 amps.
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Old Jan 26, 2009, 08:14 PM
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Quote:
Originally Posted by dvdcort
Just an FYI, I have smoked two 2w-25s in HET fans on 6s. This is with 150-200 flights. The HET fan does draw a little more than the mini fan though.
It shows that the motor is running at its limits.
dc

Beside the fact that 2W-25 releases more heat (less efficient)
and the 2W-25 draws more current (5-6 amps)on the HET fan vs. Mini fan,
if you used it on Mini fan pro with low timing and
with throttle control it might last quite longer.
And do get a good heatsink for the motor...
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Old Apr 04, 2009, 04:40 AM
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Gents Ė decided to get the Mega FAI/F5D (the poor Euro/Pound conversion hurt me a bit ). Iíve done some tests using Wemo 70mm fan, mounted in Lander F-9 Panther.

5S gives 850W (47A)
6S gives 1500W (71A)

Very encouraging indeed! I reckon 5S will be great for everyday flying and 6S when I need some extra grunt . Heat sink fitted.

I have not yet tested the Mega 16/25/2 in this setup. Expect it will be similar, but maybe in more danger of failing (apparently the Mega FAI has a Kevlar bandage, whatever that does )
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Old Apr 04, 2009, 06:52 AM
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All mega's and HET, ARC have the segmented rotors kevlar wrapped. Keeps the magnets intact at high rpm.

Fuzz
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Old Jun 23, 2009, 03:36 PM
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Quote:
Originally Posted by MaHŲ
Mega 18FAI (spezial version 16/25/2 for F5d).
6S and around 60A in a HetFan.
regards Martin
Thanks again Maho for your advice, I'm really impressed with the Mega FAI/F5D on 6S in Wemo fan (1100W at 55A). Using it in my Lander F-9 Panther. No retracts/flaps, just KiSS. Weight is around 1400g and I am seeing around 1450g thrust. Flight times are a little short on the 2 x 3S 2600mAh 35C packs (I bring her down after around 4 mins), so need to look into some 3200mAh packs. Around 10 flights now.

Jacques
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Old Jun 23, 2009, 04:55 PM
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has anybody tried this motor on 6S + minifan? similar KV as Mega 16/25/2-2650
ARC-28-47-1.5
1.5 Turn @ 12V:
No Load Current: 1.6A
KV: 2800
Weight: 113g
Shaft: 3.2 mm
Approx Weight: 110g
Poles: 4


It looks promissing though
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