RE: Official Aerobird Swift Thread

RE: Official Aerobird Swift Thread
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RE: Official Aerobird Swift Thread - 4/10/2008 1:22:59 AM

tam popo

Posts: 3033
Joined: 2/6/2007
From: glasgow, , UNITED KINGDOM
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Mongrel (JohnM) - its the same here with my original 480, its had dogs abuse, 3S, WoT in fact the lot thrown at it, and guess what, It flys one of my Strykers brilliantly - there's life in this underated old dog yet!!!

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Post #: 851

RE: Official Aerobird Swift Thread - 4/10/2008 1:29:56 AM

Zeta30

Posts: 228
Joined: 8/17/2007
From: Portland, OR, USA
Status: offline

quote:

Did you get that inrunner you were considering from United Hobbies?
What size 3S1P Lipo will you use? Have you bench tested it with APC 6x4?
How many amps/watts does the motor draw at full throttle with the Whatt-Meter?

I'm going to try a motor I had in a Heli I just replaced. I figured I wasn't doing anything with it so I may as well give it a try. Someone on a Heli board said that he uses the same motor in his Stryker and it was more power than he ever needed. The motor I'm trying is this one:

http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXLBS1&P=FR

I did order the motor from United Hobbies and it was DOA. I sent it back and am still waiting. According to their web site they shipped it so I should get another one in about a week. So if my Heli motor doesn't work out I'll put the other one in.

I don't have a watt meter so I can't measure it. That's on my tool wish list.

The updated forecast is clear sunny weather for the weekend, but at this point I'm not getting my hopes up.

(in reply to Swift427)

Post #: 852

RE: Official Aerobird Swift Thread - 4/10/2008 2:08:40 AM

The_Mongrel

Posts: 2529
Joined: 9/19/2007
From: Murrumbateman, AUSTRALIA
Status: offline

quote:

ORIGINAL: Zeta30

quote:

Did you get that inrunner you were considering from United Hobbies?
What size 3S1P Lipo will you use? Have you bench tested it with APC 6x4?
How many amps/watts does the motor draw at full throttle with the Whatt-Meter?

I'm going to try a motor I had in a Heli I just replaced. I figured I wasn't doing anything with it so I may as well give it a try. Someone on a Heli board said that he uses the same motor in his Stryker and it was more power than he ever needed. The motor I'm trying is this one:

http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXLBS1&P=FR

I did order the motor from United Hobbies and it was DOA. I sent it back and am still waiting. According to their web site they shipped it so I should get another one in about a week. So if my Heli motor doesn't work out I'll put the other one in.

I don't have a watt meter so I can't measure it. That's on my tool wish list.

The updated forecast is clear sunny weather for the weekend, but at this point I'm not getting my hopes up.

I reckon that motor will go very well!! I have similar motor in my Easy Star turning a 6x5 prop (cut down 7x5) and it takes the Easy Star to constant vert!! So think you will be fine!

Cheers
-J

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Crashing is such sweet sorrow!

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Post #: 853

RE: Official Aerobird Swift Thread - 4/10/2008 3:27:52 AM

Zeta30

Posts: 228
Joined: 8/17/2007
From: Portland, OR, USA
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I forgot to add I'll be flying a 2100mAh 3S LiPo with a 20C rating. I've got a couple of 2200mAh LiPos but I think that is getting a little heavy. I save them for my Heli and every now and then I'll slip them in my Super Cub.

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Post #: 854

RE: Official Aerobird Swift Thread - 4/11/2008 6:56:52 PM

Swift427

Posts: 482
Joined: 3/15/2007
From: Minneapolis, MN, USA
Status: offline

quote:

ORIGINAL: tam popo

Mongrel (JohnM) - its the same here with my original 480, its had dogs abuse, 3S, WoT in fact the lot thrown at it, and guess what, It flys one of my Strykers brilliantly - there's life in this underated old dog yet!!!

Not all long can 480 brushed motors are created equal (NO KIDDING!

)
Some that didn't even undergo a break-in bath before flying are still kicking

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Never Give Up, Never Slow Down, Never Grow Old, and Never Ever Die Young

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Post #: 855

RE: Official Aerobird Swift Thread - 4/13/2008 8:19:15 PM

Zeta30

Posts: 228
Joined: 8/17/2007
From: Portland, OR, USA
Status: offline

Brushless update!

The motor I went with was very strong. The only problem is that it really sucks the juice out of the batteries. I usually get about 10 min 30 sec fly time with my Trojan and Brushless Super Cub with plenty of juice to spare. I was only able to get about 7:30 of fly time with this motor. The first pack went down to the voltage cut off for my ESC which is 9.8V. I was using a Thunderpower 2100mAh 20C battery. I reset the timer on my TX to 8 minutes and I started to come in for a landing at about 7:00, when I was lining up for the landing the Battery cut off went off again.

Taking off was easy, I gave it full throttle and threw it at about a 45 degree angle and it just kept climbing. I flew at about 3/4 throttle most of the time and that seemed to be plenty of power. I didn't even throw it very hard, more like a soft lob and it took off like crazy!

I am going to try a different prop. The one I used today is an APC 6 x 5.5 pusher prop. If I go down to a 6 x 4 will that help extend the flight time?

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Post #: 856

RE: Official Aerobird Swift Thread - 4/17/2008 10:40:36 PM

Swift427

Posts: 482
Joined: 3/15/2007
From: Minneapolis, MN, USA
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CONGRATULATIONS on getting enough muscle in your Swift to make it an enjoyable flying experience.

quote:

Taking off was easy, I gave it full throttle and threw it at about a 45 degree angle and it just kept climbing. I flew at about 3/4 throttle most of the time and that seemed to be plenty of power. I didn't even throw it very hard, more like a soft lob and it took off like crazy!

Being that you fly aggressively "(WOT)" why can't you set your cut-off close to 9.0 volts as the lipo voltage should rebound to at least 9.5v. If you were flying very conservatively than I can see a higher cut off around 9.5v as the lipo may only rebound to 9.7v. The tradeoff of a beefier motor with aggressive flying is less flying time, but you have several LiPo batteries for backup-

quote:

I have 5 3S 2100 mAh and 2 2200 mAh LiPo batteries so I have plenty of packs to take out to the field.

I would hope 200 watts (12volts x 17amps) is enough for getting the 22oz Swift airborne with a brushless inrunner. Once airborne I would think 125 watts (e.g. 10.5volts x 12amps) is more than enough burst for doing your basic aerobatic maneuvers. You may have more motor muscle than you need. If you get that other inrunner from United Hobbies you should do an amperage draw comparison at 12v and 10.5v both at half throttle and full throttle. If you had an Astroflight Whatt Meter you could bench test compare each motor with the 6x4 prop.

Another variable is condition cycle vs. not condition cycling to see if there is a noticeable difference in peak performance. http://www.rcuniverse.com/forum/m_7351702/tm.htm

Let us know if tip stalling is now a thing of the past. Do you still find the low throw rate helpful or just fly with high rate setting?

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Post #: 857

RE: Official Aerobird Swift Thread - 4/18/2008 1:31:49 AM

Zeta30

Posts: 228
Joined: 8/17/2007
From: Portland, OR, USA
Status: offline

thanks for the info Swift

I don't have the stock RX and TX so I don't have High/Low rates. I can program my TX for different rates but just kept the servos at 100% throw and no expo.

With the two packs I put through it last weekend I had no tip stall.

I swear I checked United Hobby web site two weeks ago and my mtoor status said shipped. Now it is back to reserved. I'm going to have to send an e-mail because they received the defective one almost a month ago and the new one should have been shipped by now.

(in reply to Swift427)

Post #: 858

RE: Official Aerobird Swift Thread - 4/18/2008 1:50:12 AM

The_Mongrel

Posts: 2529
Joined: 9/19/2007
From: Murrumbateman, AUSTRALIA
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quote:

I would hope 200 watts (12volts x 17amps) is enough for getting the 22oz Swift airborne with a brushless inrunner.

Be careful with these calculations as the battery will not maintain 12v being drawn at 17A. Depending on the batteries output specs, it may drop as low as 10v which will affect your calculations. You will need to take into consideration the 'C' rating of the battery. I would suggest a Watt meter to get an accurate reading, and not rely on the basic calculations.

Cheers
-J

< Message edited by The_Mongrel -- 4/18/2008 1:57:47 AM >

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Post #: 859

RE: Official Aerobird Swift Thread - 4/18/2008 2:49:09 AM

Swift427

Posts: 482
Joined: 3/15/2007
From: Minneapolis, MN, USA
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quote:

I am going to try a different prop. The one I used today is an APC 6 x 5.5 pusher prop. If I go down to a 6 x 4 will that help extend the flight time?

Yes (If the throttle management is identical for both). Ideally, there is a sweet spot (prop size) that results in a motors best efficiency (Prop Load).

What would be interesting is to try a 6x3 prop being that you already have enough power and see how much it increases flying time. You can use a conventional right-hand APC 6x3 tractor prop by reversing the motor from CW to CCW rotation and reverse mounting the tractor prop. The Catch22 is that you will have to increase to full throttle if you want to get the same speed as you were getting with the 6x5.5 prop at 3/4 throttle. 2850Kv is certainly going to draw the amps with a 6x5.5 prop as the motor is not spinning as efficiently as with a 6x3 prop. The 6x3 will also allow the motor to spin the 6x3 prop at a higher rpm than it was spinning the 6x5.5 at higher throttle settings.

The PropLoadFactor would be reduced from 33 to 18, and if you don't need to fly/race all that fast than the 6x3 might offer the best compromise. The other thing is that the motor will run at least 10% more efficient with a 6x3 prop than the 6x5.5 prop. A 6x3 prop powered by a fully charged (12.5v) 3-cell LiPo should be more than enough for successful hand launching without tip stalling.

6x3=18 PLF
6x4=24 PLF
6x5.5=33 PLF

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Post #: 860

RE: Official Aerobird Swift Thread - 4/18/2008 2:59:37 AM

Swift427

Posts: 482
Joined: 3/15/2007
From: Minneapolis, MN, USA
Status: offline

quote:

I would hope 200 watts (12volts x 17amps) is enough for getting the 22oz Swift airborne with a brushless inrunner.

The idea is that the LiPo is at its fullest charge during the initial full throttle launch. During these several seconds the LiPo may go somewhere from 12.5 volts to 11.5 volts or 12 volts average. With a 6x3 prop this should be more than enough power to get airborne.

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Never Give Up, Never Slow Down, Never Grow Old, and Never Ever Die Young

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Post #: 861

RE: Official Aerobird Swift Thread - 4/18/2008 3:57:53 AM

Zeta30

Posts: 228
Joined: 8/17/2007
From: Portland, OR, USA
Status: offline

I just checked United Hobbies again it says the motor has been shipped. I'll check again in a few days to see if it changes back to reserved.

I may be able to get to a hobby store this weekend I'll check out props if I do. I'll pick up a 6X4 and 6X3 and see how they do.

All these variables are just too confusing for my simple mind to grasp.

(in reply to Swift427)

Post #: 862

RE: Official Aerobird Swift Thread - 4/18/2008 4:40:20 AM