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Old Oct 17, 2012, 02:40 PM
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brushless55's Avatar
United States, CO, Longmont
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Originally Posted by Webmaister View Post
Don't forget the Carbon Rods.
Like several!
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Old Oct 17, 2012, 04:23 PM
olllian
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United States, AZ, Chandler
Joined Nov 2011
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Originally Posted by Webmaister View Post
Here's the latest speed experiment with Marie. Swapped out the prop configuration on 8S. Want to know what a 740kv motor sounds like on 8S?
The GPS at the end of the video logged 132 mph.

Sorry about some of the camera shots. This was my maiden on my homemade head camera solution. Still need to adjust the angle a bit but not bad for zero investment since I got the camera free.


http://youtu.be/jNCZNTFy9Yg
What motor are u using?
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Old Oct 18, 2012, 04:34 AM
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Madrid, Spain
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Originally Posted by jgalexander View Post
Yeah, that's what the specs say. What has me wondering is that 2000W limit. Seems like it ought to be able to handle the additional heat as long as I stay away from the watt limit, no?
No

The limit could be the rpm, not the watage. It usually is not a problem, but it may be if the bearings cannot handle the increased rpm

Why not using a bigger/more pitched prop? Easier, cheaper and problem free for peace of mind
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Old Oct 18, 2012, 08:51 AM
I like Fast Warbirds
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United States, GA, Atlanta
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Originally Posted by jgalexander View Post
Yeah, that's what the specs say. What has me wondering is that 2000W limit. Seems like it ought to be able to handle the additional heat as long as I stay away from the watt limit, no?
Heat as in amps? I 've run lesser quality motors 500 watts over the spec without issue so I would bet that a Scorpion would do 500 over without issue as well.
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Old Oct 18, 2012, 08:52 AM
I like Fast Warbirds
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United States, GA, Atlanta
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Originally Posted by olllian View Post
What motor are u using?
Scorpion HK 4025-740
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Old Oct 18, 2012, 01:00 PM
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USA, GA, Atlanta
Joined Nov 2008
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Well I am sure I will continue to lurk around here every now and then... but I did sell my SD50 over the weekend at HHAEFI

Tough to part with, but I think there may be a Formula 1 size in my future
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Old Oct 18, 2012, 02:09 PM
Flying Full Size & Fun Size :)
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United States, CA, Calabasas
Joined Apr 2010
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Quote:
Originally Posted by AndrésMtnez View Post
No

The limit could be the rpm, not the watage. It usually is not a problem, but it may be if the bearings cannot handle the increased rpm

Why not using a bigger/more pitched prop? Easier, cheaper and problem free for peace of mind
Well, I may go with a 10x12 or 11x12 prop, and see what that gets me until I clarify what my voltage options are with the motor.


Quote:
Originally Posted by Webmaister View Post
Heat as in amps? I 've run lesser quality motors 500 watts over the spec without issue so I would bet that a Scorpion would do 500 over without issue as well.
Heat as in the ~10-15% of energy input that gets lost due to inefficiency.

I was thinking of the 3watts/gram rule (more like 5 for scorpion motors I think), and figuring as long as I kept things reasonable watt-wise, I'd be good.
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Old Oct 21, 2012, 04:38 PM
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Sundowner 50

Well , today I finally had the opportunity to check the speed of my Sundowner 50 using a GPS system. On freshly charged 8 cells 40c battery pack and a 12x12 APC prop, the plane recorded a top speed of 147.3 mph at level flight. Didn't quite make 150 mph, which was the goal, but think it is possible with at different type of prop. Will try again next weekend.
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Old Oct 21, 2012, 10:31 PM
DFC~ We Do Flyin' Right
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Congrats Vantage! That really is impressive with this airframe.

There has not been examples of this airframe going past [I think] about 160mph without breaking apart; have you done anything to give the airframe more structural integrity?

I cant wait to see your vids!!!
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Old Oct 22, 2012, 08:06 AM
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No mods were made to the airframe. At this point, I don't think I'll be able to get much more than 150mph with the motor/esc/prop combo being used.
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Old Nov 06, 2012, 07:58 PM
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lll
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Old Dec 12, 2012, 01:34 PM
Fill'er Up!
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Oxnard, Ca
Joined Oct 2008
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Hello all, been away for a while, my sundowner was sitting for a while with motor issues.

For sake of another data point, I got the new Turnigy Helidrive SK3 4962 480kv. On a 12x12 10S 45-90 4000mah, after 30sec pull it does 3150W, 92A at ~34v. Motor is only warm to the touch. I plan to play with props, but this is another good high power and cheap option for the Sundowner.

http://www.hobbyking.com/hobbyking/s...ize_heli_.html
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Old Dec 14, 2012, 12:46 AM
olllian
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United States, AZ, Chandler
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Originally Posted by mattyhawk View Post
Hello all, been away for a while, my sundowner was sitting for a while with motor issues.

For sake of another data point, I got the new Turnigy Helidrive SK3 4962 480kv. On a 12x12 10S 45-90 4000mah, after 30sec pull it does 3150W, 92A at ~34v. Motor is only warm to the touch. I plan to play with props, but this is another good high power and cheap option for the Sundowner.

http://www.hobbyking.com/hobbyking/s...ize_heli_.html
I got the 560kv one. I am going to swap out my 400kv scorpion and try it out!
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Old Dec 14, 2012, 12:47 AM
olllian
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United States, AZ, Chandler
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Quote:
Originally Posted by Vantagepoint View Post
Well , today I finally had the opportunity to check the speed of my Sundowner 50 using a GPS system. On freshly charged 8 cells 40c battery pack and a 12x12 APC prop, the plane recorded a top speed of 147.3 mph at level flight. Didn't quite make 150 mph, which was the goal, but think it is possible with at different type of prop. Will try again next weekend.
What kv are you running?
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Old Dec 14, 2012, 09:07 AM
Fill'er Up!
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Oxnard, Ca
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Originally Posted by olllian View Post
I got the 560kv one. I am going to swap out my 400kv scorpion and try it out!
I don't think you will be disappointed. The T600 880kv I mod'd to 475kv was consuming 3400W on 10S, this T700 480kv is consuming almost 3200W on the same batts and prop. Big difference is the T700 is heavier (because it is longer) and it gets midly warm at 92A where the T600 was moderately warm to almost hot at 92A and therefore was at its limit. The T700 is not at its limit and could handle a bit more pitch for more speed.

The interesting thing about the T600 880kv mod'd was running was doing the same as the 4035 Scorpion others were using on 10S with the same speed. I expect the T700 to perform as well or better than the Scorpion 4035, but with a weight penalty. The thing on the T700, the price is oh so nice!

I never suggested my T600 motor setup because it was not turn key and most people would be turned off to moding a new motor. The T700 on the other hand is out of the box ready for some power at a low price.

EDIT:

I found that the T700 is the Align 750MX Brushless Motor. They come in 450KV and 530kv flavors. they say they can handle 100A continuous / 165A peak or up to 4500W on 12s. I wonder if the HK versions can do it.
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Last edited by mattyhawk; Dec 14, 2012 at 10:29 AM.
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