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Jun 13, 2006, 06:55 PM
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Thread OP
Discussion

Cost effective power system for Omega 1.8E


I've been tooling around with an Ascent (polyhedral, brushed glider)
and liking it, so I want to get into a 2meter with ailer/flaperons.

The Omega 1.8E (nesail.com) looks like a fun bird, but I have two
concerns:

1: V-tail - is there a drawback to these? My radio can handle it
with PGMX1/2 mixing, but I'm concerned about drag and stability.

2: Power system - I'm on a budget and discovered I have to use
a planetary gearbox (PGB) with a spare motor I have (no room in nose
for an offset gearbox). Unfortunately, there isn't a PGB on the
planet that fits my spare motor (mamba 3600KV 20mm can). I'd
like to be able to climb out at 45 to 80 degrees if possible and nesail
recommends a hacker B20-18L with 4.4:1 maxon PGB (over $140!).
Is there a more cost effective motor for use with my TP2100 3s1p's and a phoenix25?

thanks,
edfardos
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Jun 14, 2006, 09:10 AM
the kitty litter of rcgroups
rdwoebke's Avatar
Quote:
Originally Posted by edfardos
Is there a more cost effective motor for use with my TP2100 3s1p's and a phoenix25?

thanks,
edfardos
Would an outrunner fit? Perhaps a Hacker A20? I know the New Mexico boys are using the A20 series in planes of that size. You might even be able to make your own (from either a kit or CDROM parts). Outrunners are really comming down in price and have a lot of torque.

I am new to brushless, but recently built my first brushless from a discarded CDROM. It is on a very small glider, but gives me hope for larger projects.

Ryan
Latest blog entry: Supergee wing mount pylons
Jun 14, 2006, 09:31 AM
Registered User
Thread OP
Yah, i was considering an outrunner, but I've not been real happy
with the hacker a20-20l (noisy, if you can find a working, non-
melted one). Plus a bad landing could destroy an expensive
motor (vs a cheap(er) gearbox).

I'll try to save up for a B20-18/Maxon combo i guess (140 bucks or
so?) unless there's a better option.

--edfardos
Jun 14, 2006, 09:33 AM
Registered User
I have a Himaxx 2812-850 outrunner in my Omega 1.8 with a 10x8" Graupner folding prop and a 3s1p 1500mAh Polyquest Lipo battery. This is a very light, silent (no gear), and probably one of the cheapest brushless setups for this plane. Static current is about 14 Amps. This outrunner fits easily in the nose, just make sure that nothing (like cables) touches the rotating can. Climb angle is 60deg or more, it takes about 10-15sec to get to soaring altitude. Even without thermals I could easily fly for 45min or longer with this setup.

The rudder reaction of the Omega is relatively weak, not sure if that is due to the v-tail. Other than that the v-tail is just fine. A flying buddy and I replaced the wing joiner with a slighty bent steel rod to increase dihedral a little. That makes the plane a little more stable when circling in thermals.

Hope that helps,

Mibbl
Jun 14, 2006, 09:46 AM
the kitty litter of rcgroups
rdwoebke's Avatar
Quote:
Originally Posted by edfardos
Yah, i was considering an outrunner, but I've not been real happy
with the hacker a20-20l (noisy, if you can find a working, non-
melted one). Plus a bad landing could destroy an expensive
motor (vs a cheap(er) gearbox).
Outrunners are noisier than a gearbox? I would not have expected that....

Aren't gearboxes like $50-$60? And an outrunner is like $50-$60? So would it not be a wash in a crash?

And that said, it seems like you can do repair work on outrunners....

Ryan
Latest blog entry: Supergee wing mount pylons
Jun 14, 2006, 10:12 AM
I am a Leaf on the Wind
Soaring Tiger's Avatar
I have the new Omega II 1.8E. I am still building it but I put a Hyperion Z3013-16 outrunner in mine because I did not want the added cost of a gearbox. I do not plan on landing nose first so I hope I will not have to worry about destroying the motor. BTW, this motor barely fits. I've heard of others using the Hyperion motors and they report that they get great performance; I hope I do too We'll see.

Esprit Model was having a clearance sale on them for $68 but they are sold out. They do have the 14 turn however. Also Bishop Power Products & AlleRC have them for $79.95. Not cheap but less than the hacker with a gearbox.

I plan on using my TP 2100 3 cell packs and an 11x6 prop. I ran the numbers in MotoCalc and it says the max amps I'll draw is 26.5.

Dave
Jun 14, 2006, 11:16 AM
Registered User
edfardos-

I'm using Hobby Lobby's Esskay 400XT outrunner ($19.90 on their backorder sale) outrunner on a 1.5m Mini Silent Dream with great results. Using Cool Running 10a esc ($29.95), 9x5 Graupner folding CAM prop on Dymond 3.0mm hub/spinner assembly, and 1100 mah 3s lipo. The weight reduction (AUW is now 18 oz.) and stronger power plant over planetary geared S400 turned a dog into an eagle. Not vertical performance, but strong enough to climb to near speck out height in around 20 seconds.

Jim
Last edited by JimO; Jun 14, 2006 at 11:33 AM.
Jun 14, 2006, 08:25 PM
Registered User
flyfalcons's Avatar
The Hacker A20 is a great little motor. I've smacked mine HARD twice after two elevator servo failures in my Super Cap (straight in from 40 feet). All I did was replace the shaft and the motor still runs great. If I had a lighter glider that needed a motor I wouldn't hesitate to put one in it. $100 for a motor/esc combo isn't a bad deal.
Jun 15, 2006, 12:55 PM
Pontificating Member
tone's Avatar
I have a mega 400/15/5 in mine (64$ at mega right now) with an APC 9x4.5 on 3S 1320 lipos. I also have the same setup in my Ascent. Both climb out at around 65-80 degrees and get to around 250-300 feet in around 10 seconds. Pulls 12.5 amps out of the 3S pack. I could prop for more, but i like my packs to last.

The Ascent is around 17.5-18oz. the Omega is around 18-18.5oz.
Both are really nice. I think the Ascent is the best value in sailplanes.
Cheap, light, easy to get to fly well and thermals fantastically. Many times i have had to drag it out of lift because it was getting to small for the old eyes to easily see.
Love that glowing red/orange covering with the sun on it...

Mega doesn't get any credit for how good their outrunners are.

if you go with a himax, i would go for one over 1000kv like a 2812-1080 and use a bit smaller prop. (9x5 or 8x4).. I feel like the Omega wing generates more lift at a little higher speed.
Jun 15, 2006, 02:05 PM
Registered User
Thread OP
Wow - thanks for the info!

I think I may order the OmegaII and try my Hacker A20-20L which is in another
plane (4th one on warranty, but it works great). This motor pulls 22 amps
static with a 10x4.7APC prop -- can I expect the same with a Cam folding prop
with the same specs? While the hacker A20 is suggested here, has anyone
tried it? I like the Himaxx ideas too - which himax is closer to the a20-20
(the 2812 850 or the 1080?).

Re the Ascent - I have one and fly it almost every day (direct speed400 seriously
sucks, and there's no ailerons). Somebody mentioned dihedral too - are you
constantly correcting for roll in the OmegaII? That'd be impossible when the
plane gets hard to see wouldn't it?


thanks again for all this great info... I'm between the himaxx 2812(1080 or 810?)
or the hacker a20-20L (the latter of which has given me problems in other
planes - really loud, yes louder than a gearbox, or melted at 20A)

r,
edfardos
Jun 15, 2006, 02:24 PM
the kitty litter of rcgroups
rdwoebke's Avatar
Quote:
Originally Posted by edfardos
While the hacker A20 is suggested here, has anyone
tried it?
Ed,

If you do some searches, you will find a number of the New Mexico boys are using Hacker A20s in "speed 400 class" ships and having great results. Not sure if they run the A20-20 or a20-22. They have actually designed a competition class around this size motor.....



Quote:
Originally Posted by edfardos
planes - really loud, yes louder than a gearbox, or melted at 20A)

My read on the Hacker website is that it is not designed for 20 amps.... Perhaps that is why they burn out for you?

http://www.hackerbrushless.com/motors_a20.shtml

Good luck with whatever you go with...

Ryan
Latest blog entry: Supergee wing mount pylons
Jun 15, 2006, 02:47 PM
Pontificating Member
tone's Avatar
Ryan -
That is cool about the 'Hacker Class'.. I like it!

Edfardos -
Yes the Omega requires a lot more focus on the aircraft at all times in flight.
Kinda like thermalling a 3Der. i have made some trims and adjustments and the Omega is a lot less twitchy feeling than it was, but nothing like the poly Ascent for Easy on the nerves.

If you want a better glider, i say just slip your Hacker in the Ascent.
Prop down to use a lighter lipoly and you will be amazed.
You will be at least an ounce lighter than the speed 400, and the plane will signal lift better and climb on bug burps.
Jun 15, 2006, 03:12 PM
the kitty litter of rcgroups
rdwoebke's Avatar
Quote:
Originally Posted by tone
Ryan -
That is cool about the 'Hacker Class'.. I like it!
Actually, it is an "Outrunner Class". Not just for Hackers...

http://www.soarabq.org/f5j_wc_2006/f5j_main.shtml

http://www.soarabq.org/pdfs/f5j_rules.pdf

It is just that the A20 is very popular amongst the guys pioneering this class.

Ryan
Latest blog entry: Supergee wing mount pylons
Jun 15, 2006, 04:08 PM
3 Sons - Legos and Lift
2motheus's Avatar
Quote:
Originally Posted by rdwoebke

I am new to brushless, but recently built my first brushless from a discarded CDROM. It is on a very small glider, but gives me hope for larger projects.

Ryan
Did you rewind the motor? Put in magnets? Run stock? What speed controller?

I'm interested in motorizing a small glider and have access to old CDROM motors.
Jun 15, 2006, 04:25 PM
the kitty litter of rcgroups
rdwoebke's Avatar
Quote:
Originally Posted by 2motheus
Did you rewind the motor? Put in magnets? Run stock? What speed controller?

I'm interested in motorizing a small glider and have access to old CDROM motors.
Yes, I rewound it. It was very easy. Way easier than I thought it would be. I optimized my motor due to 2 things. First, a company was having a sale on a 3S 300 mA lipo for $8.50. I bought 2. But, this battery had a peak draw of 4 amps, so I wanted my motor to draw less than that. I ran it through a calculator (at gobrushless.com) and my setup I figured should draw about 3.7 amps at full throttle. Wattmeter confirms that is about right. Second, I happened to have a 6x3 folder and I wanted to use that.

This motor I pulled out of a CDROM a friend gave me. I rewound the motor with 20 turns of 26 guage wire. I happened to have some of this from Radio Shack. I also replaced the stock "ring" magnet with 12 N45 magnets (from aircraft world, the place I got the battery). These were just a few bucks. I replaced the stock shaft with one that had a 2.3 mm output for my little folder (also from aircraft world). Finally, I added little gold "bullet" connectors. I figure I have about $8.00 in this motor. Would be about half that if I had not opted for the gold "bullet" connectors (nice, but kind of overkill in this application).

I am using the Horizon 20 amp ESC, but in reality, a cheaper one would be fine for my setup. It is just that this catalog was handy around Christmas time and my wife likes me to circle things as a wish list and then she picks some things to get me. This happened to be under the tree this year.

For a small glider, this worked very well. It would work well on a larger glider too, I think. It is just that I wanted to be around 7.5 ounces for my model so that limited the battery I could use and that of course limited current it could put out. I think it delivers about 6.5 ounces of thrust at full throttle.

Ryan
Latest blog entry: Supergee wing mount pylons


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