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Old Aug 23, 2011, 08:39 PM
TexasAggie is offline
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Gig 'Em!
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30A will be plenty for the ESCs for a TS; mine are 18A.

As you're picking parts, you should be figuring out how much thrust you want and how fast you want it to go, numerically. You can use these numbers in a calculator to tell you what prop to use. I'll run a few samples for you to demonstrate:

Start with 1050kv. With an APC-E 8x8 you can get to 65 mph with 44 oz total thrust and 15.5 A per motor.
With the same motor, you could also put on a 9x6 and get 60 oz. of thrust with a top speed of 48 mph and the same 15.5 A drawn (that's probably total overkill).

With an 1100 kv motor, you could have a top speed of 51 mph, nearly 50 oz. of thrust, and 13A drawn with an 8x6.

Roughly speaking, a motor with kv between about 900 and 1300 should work fine. I use 900.

This is the calculator I'm using to come up with these values: http://flbeagle.rchomepage.com/softw..._imperial.html
A great tutorial is here: https://www.rcgroups.com/forums/show....php?t=1136470
If you want to play around with it yourself, the TS's numbers are:

weight: 44 oz. A pretty good estimate for an average TS
wingspan: 56 in
wing area: 676.8 sq. in.
number of props: 2
max prop size: 10

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Old Aug 24, 2011, 06:30 AM
steve1814 is offline
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One cell short of a Pack
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Looking for a couple of the Motor Mounts


Looking for two of the Twinstar Motor mounts. if you have one or two, PM me please!

Cheers,
Steve
Old Aug 24, 2011, 06:17 PM
Hughie Shiel is offline
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Hi guys, bit 'off piste' but always found you guys helpful : )
Just rebuilt my TwinStar Brushless after having to buy a new wing. Would like to have said it was due to some spectacular aerial adventure but no, a drunken stumble!!!
Anyways was moving my Spektrum AR500 receiver and the tape pulled off the last silver braided bit of the Ariel away from the rest of the grey ariel.... It's about an 1" long, (2.5 cm), and does 'poke back in' but obviously won't stay there. Should I try and strip back the grey insulation and solder this peice back on or will the loss of this bit not affect the range much? Cheers, Hughie
Old Aug 30, 2011, 10:24 AM
bigandy is offline
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Pesky Landings!
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Hi Folks,

I'm considering putting together a Twinstar to use as an Aerial Photography platform. The unobstructed view from the nose will be perfect for videos. I was just wondering if anyone could tell me what the vertical distance is between the underside of the fuselage and the centreline of the motor mount? I'm looking at the sort of size props I can squeeze in there without there beinga ground clearance issue?

Thanks!
Andy
Old Aug 30, 2011, 10:34 AM
NeveSSL is offline
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So many UMs, so little money.
I think 9" is the largest you can use without issue. I've noticed a lot of people, myself including, using 8x6 props with great efficiency, depending on your motor of course. I have also used 9x6, but my motors came down hot. I wouldn't feel comfortable running 10" props without landing gear.

Brandon
Old Aug 30, 2011, 11:42 AM
RobC(UK) is offline
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**** 37130 ****
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For Slide Off Ground take off, 8" are the largest diameter props you can safely use. With wheels fitted you could use up to 12" props.
Old Aug 30, 2011, 11:45 AM
bigandy is offline
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Pesky Landings!
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Cheers folks. I've not decided on motors yet, but I'll look to size them to suit a 7 or 8 inch diameter prop I want to be able to climb quickly with a decent payload onboard, so perhaps the 8 inch props are the ones to go for.

Andy
Old Aug 30, 2011, 09:12 PM
flyingflipper is offline
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Brushless Power Curve


My Twinstar II is ready for it's maiden flight. When I ran up the motor on my test stand, the motors peaked at about 1/2 throttle. The battery is fully charged and the trim on the radio is trimmed right. If I pushed the stick past 1/2 throttle, there isn't any increase. I'm not looking for a speed demon - it was enough to hold it back during the run up!

The watt meter showed 360 watts and 34.5 amps.

So is what I am experiencing normal for my setup?

TP ProLite v2 3S/3300 mAh
Spektrum DX6i radio and receiver
Multiplex Power Pack:
* (2) Himax 2812-1080 Brushless Motors
* (2) 9 x 6 APC Props, (2) Hub and Driver sets
* (2) MULTIcont BL-17 ESC's

Thanks
Old Aug 30, 2011, 09:58 PM
antonlubo is offline
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Quote:
Originally Posted by flyingflipper View Post
My Twinstar II is ready for it's maiden flight. When I ran up the motor on my test stand, the motors peaked at about 1/2 throttle. The battery is fully charged and the trim on the radio is trimmed right. If I pushed the stick past 1/2 throttle, there isn't any increase. I'm not looking for a speed demon - it was enough to hold it back during the run up!

The watt meter showed 360 watts and 34.5 amps.

So is what I am experiencing normal for my setup?

TP ProLite v2 3S/3300 mAh
Spektrum DX6i radio and receiver
Multiplex Power Pack:
* (2) Himax 2812-1080 Brushless Motors
* (2) 9 x 6 APC Props, (2) Hub and Driver sets
* (2) MULTIcont BL-17 ESC's

Thanks
According to the Himax site, those motors should output the followsing:
HC2812-1080 Kv = 1080, Rm = .111, Io = 0.75, Efficient Operating Current = 5-13A, 15A Max 15 seconds

If you're getting 34.5 amps with two motors (radio should be negligible), something is fuzzy somewhere. Did you calibrate the esc's to work with those motors? Maybe one of those more knowledgeable about such things would chime in. Good luck...Tony
Old Aug 31, 2011, 12:17 AM
NeveSSL is offline
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So many UMs, so little money.
I know some ESCs require that you calibrate your throttle input. Mine did. Check the documentation of your ESCs. Mine were running completely different speeds until I calibrated them to my throttle.

Also, 34.5 amps doesn't sound good if they're only supposed to pull 26 continuous or 30 for 15 seconds. That seems to point even more at your ESCs not being calibrated to your throttle.

Brandon
Old Aug 31, 2011, 03:09 AM
flyingflipper is offline
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Thanks for the advice. I'll check into this right away before I maiden it
Old Sep 01, 2011, 06:35 PM
NeveSSL is offline
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So many UMs, so little money.
Has anyone mounted a GoPro to their TwinStar yet?

I'm getting one tomorrow and I'm thinking I'm probably just going to stick it on the wing as close to the fuselage as I can and angle it down and to the side. I'm wanting to do more of an aerial video/photo thing than FPV (for now ). Do you guys think that would be alright? I may have to put some counter weight on the other wing, but I'm not expecting to have to put much if any.

Brandon
Old Sep 01, 2011, 06:45 PM
TexasAggie is offline
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Plenty of people. Youtube has lots of examples. ReadymadeRC sells a GoPro mount for the TS. Most people remove the canopy and use that space for mounting cameras. That's what I did before I lost my two... It might be a bit more complicated to get it mounted securely to the wing, but I doubt it would give the plane any problems.
Old Sep 01, 2011, 06:56 PM
NeveSSL is offline
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So many UMs, so little money.
Thanks bro.

I did a search the other day and was surprised to see how many TwinStars are being used for FPV. Makes sense, though! Its where I would start if I was getting into FPV. Plenty of PayLoad.

Brandon
Old Sep 02, 2011, 06:36 PM
lord chris is offline
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RAFMAA
Hello.
just thought id drop in and say
i have a twinstar on the way! with the build focus on an FPV platform!
i thought id snoop around in here and look for a nice power set up to give me some long ish flight times!
also looking for a nice easy paint scheme. thinking Canadian search and rescue.
Chris


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