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Old Jul 18, 2005, 10:06 AM
agapornis
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Jurgen ....Thank you for your Help !
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Old Jul 19, 2005, 01:54 AM
Does it come in Flouro??
Numb Thumbs's Avatar
Melbourne, Australia
Joined Sep 2004
706 Posts
Muckin' about with outrunners

I have been playing around with a pair of Himark C2808-1360 outrunners on the TwinStar.

I am using a pair of Castle Creations 10 amp ESC's mounted at the motors and a PolyQuest 2600 mAh 3S LiPo. All up flying weight is 1080 grams.

Using a 6x4 APC prop (I can't get a Graupner in Oz around that size! ) I get:

750 grams Thrust / 11,200 RPM / 12.3 Amps (Total)

Using a 7x4 APC (no Graupner available ) I get:

970 grams Thrust / 10,000 RPM / 16.2 amps

Using the brushed 8.4 volt Speed400 motors I get:

Stock Props

660 grams / 13,000 RPM / 19.1 amps

Graupner 5.3x4.5

710 grams / 12,600 RPM / 19.5 amps

So on 7x4 prop I am getting 260 grams more thrust at 3 less amps than the Graupner prop on Speed400's. Or on a 6x4 prop, roughly the same thrust as the Graupner props on the brushed motors and 6 less amps.

Hmmm... Wish I could get more sizes in a Graupner here...

Cheers

Numb Thumbs
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Old Jul 19, 2005, 02:51 PM
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Jurgen Heilig's Avatar
53859 Niederkassel, Germany
Joined Sep 2000
18,758 Posts
Quote:
Originally Posted by Numb Thumbs
...
I am using a pair of Castle Creations 10 amp ESC's mounted at the motors and a PolyQuest 2600 mAh 3S LiPo. All up flying weight is 1080 grams.
...

Using the brushed 8.4 volt Speed400 motors I get:

Stock Props

660 grams / 13,000 RPM / 19.1 amps

...

Cheers

Numb Thumbs
Standard Permax 400, 6V for comparison:

8,8V - 25,6A - 220W - 14520 rpm

Jürgen
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Old Jul 19, 2005, 04:36 PM
Does it come in Flouro??
Numb Thumbs's Avatar
Melbourne, Australia
Joined Sep 2004
706 Posts
Oops

The numbers weren't quite correct for the outrunners...

The outrunner was rubbing slightly on the motor mount!

Actual figures, after abit of dremel work (I feel like a dentist!):

7x4 APC : 1080 grams thrust / 10,000 RPM / 15 amps

It is a 1 to 1 trust to weight ratio now. And I am saving a heap of amps!

It would be interesting to know how the "Watts" calculations convert to real energy available! If I am pulling 15 amps at 11 volts that is a theoretical 165 Watts, but I'd bet it has a heck of a lot more grunt than the 220 Watts of the stock setup! So is that where the "efficiency" of brushless comes in???

Cheers

Numb Thumbs
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Old Jul 19, 2005, 06:53 PM
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Hemet, California, United States
Joined Aug 2001
2,590 Posts
Hi Numbs,

Can you tell me who carries the "Highmark" outrunners?

Thanks! Mickydee
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Old Jul 19, 2005, 08:40 PM
Does it come in Flouro??
Numb Thumbs's Avatar
Melbourne, Australia
Joined Sep 2004
706 Posts
Mickydee

G'Day

I got them locally here DownUnder so I guess you want a US source???

They are a tiny little motors about half the size of a Speed400. They rub slightly on the plastic motor mounts - they were designed to hold a Speed400 firmly so I am not really surprised. Only took 2 minutes with a Dremel to grind off the bits that touched. A sharp blade would do the job.

I'm at work at present - don't tell the boss! - but as soon as I get home I think I can put my hands on a magazine with ads for companies selling the brand in the USA.

I'll also post a flight test as soon as I can find the time to toss it in the air!

I'll also put a video on my web site as soon as I can:

http://www.numbthumbsandloopy.net

Cheers

Numb Thumbs

Ps My 12 year old son is Loopy and I am sure he will THOUROUGHLY test the TwinStar II with these motors!
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Old Jul 19, 2005, 09:56 PM
We got planes to build
dmiller's Avatar
Dallas, TX
Joined Sep 2001
521 Posts
Quote:
Originally Posted by Numb Thumbs
...........It would be interesting to know how the "Watts" calculations convert to real energy available! If I am pulling 15 amps at 11 volts that is a theoretical 165 Watts, but I'd bet it has a heck of a lot more grunt than the 220 Watts of the stock setup! So is that where the "efficiency" of brushless comes in???

Cheers

Numb Thumbs
Part of the equation is efficiency, but you said you are now spinning a 7x4 prop at 10,000 rpm. The stock motors and props were spinning at ~13,000 and are a 4.5inch pitch. So what you are trading is pitch speed for more thrust. You can spin a large prop real slow and get plenty of thrust, but pitch speed will be real slow, or on the same wattage you can spin a small diameter prop real fast with low (relatively) thrust but high pitch speed. The trick is matching speed and thrust to your plane.

Dave
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Old Jul 19, 2005, 11:52 PM
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Jurgen Heilig's Avatar
53859 Niederkassel, Germany
Joined Sep 2000
18,758 Posts
Quote:
Originally Posted by Numb Thumbs
The numbers weren't quite correct for the outrunners...

The outrunner was rubbing slightly on the motor mount!

Actual figures, after abit of dremel work (I feel like a dentist!):

7x4 APC : 1080 grams thrust / 10,000 RPM / 15 amps

It is a 1 to 1 trust to weight ratio now. And I am saving a heap of amps!

It would be interesting to know how the "Watts" calculations convert to real energy available! If I am pulling 15 amps at 11 volts that is a theoretical 165 Watts, but I'd bet it has a heck of a lot more grunt than the 220 Watts of the stock setup! So is that where the "efficiency" of brushless comes in???

Cheers

Numb Thumbs
Strange - same rpm more thrust? Your rpm figure should be higher now.

The 220W is "Power in". At 12.8A the motors are running at less than 50% efficiency, i.e. motor shaft power per motor is less than 50W.

Your brushless motors at 7.5A probably run at approx. 75%, i.e. you have almost 62W motor shaft power per motor.

Bigger props are usually also more efficient than smaller props, but also the pitch speed needs to suit the model for good performance.

During launch at full throttle the standard Permax 400 are pretty inefficient with the Günther props. Cruising along at 30mph at half throttle things look a lot better. Current per motor is now down to a mere 5A and the motors run at approx. 70% efficiency - even the brushless motor is not that much better here (but stills turns the more efficient bigger prop).

Jürgen
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Old Jul 20, 2005, 12:26 AM
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53859 Niederkassel, Germany
Joined Sep 2000
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Quote:
Originally Posted by Numb Thumbs
...
I am using a pair of Castle Creations 10 amp ESC's mounted at the motors and a PolyQuest 2600 mAh 3S LiPo. All up flying weight is 1080 grams.
...
Cheers

Numb Thumbs
Warning: I wouldn't consider the BEC of a 10A ESC capable to support 4 powerful servos in such a model. With 2 Lipos Ok, but with 3?

Jürgen
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Old Jul 20, 2005, 04:19 AM
Does it come in Flouro??
Numb Thumbs's Avatar
Melbourne, Australia
Joined Sep 2004
706 Posts
Himark outrunners

Mickydee

I got mine from Roj's Hobbies:

http://www.rojshobbies.com/Electric%20planes.html

If necessary I'm sure he could send you some! Bottom of this page, right hand side called Himark C2808 - 26.

There is a pile of figures on them here:

http://www.daddyhobby.com/forum/showthread.php?t=3021

I have not seen them on any USA sites yet, but I can't say I have been looking all that hard! They may well be called something else in the USA.

Aircraft World might be worth a try, but their web site seems to be down at present so I can't look for you.

http://www.aircraft-world.com

There are bound to be other outrunners with similar figures to the Himark ones.

Good luck!

Cheers

Numb Thumbs
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Old Jul 20, 2005, 06:11 AM
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Joined Feb 2005
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Hello !!
Here is my twinstar 2 : http://img301.imageshack.us/my.php?i...tar20030qe.jpg
It it weighs approximately 1350g with my 8/kan2000 pack.
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Old Jul 20, 2005, 06:19 AM
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it's an old photography, since, I completely sandpapered it
sorry for my english ...
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Old Jul 20, 2005, 06:40 AM
sensitive artsy type
Treetop's Avatar
Tucker, Georgia, United States
Joined Feb 2004
3,166 Posts
maverick6, nice pic, your English is fine, where are you from?

Does the TSII fly well with the Kan2000 8cell? I am estimating about 350 grams for that pack, do you get much flight time? tt
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Old Jul 20, 2005, 06:55 AM
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My ts2 didn't fly for the moment.
I bought 2 8/kan2000 pack, that will give me a sufficient autonomy ( I think ). ( a good time of flight ??? ).
Quote:
I study Russian in first language and I am study in the college (in France).
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Old Jul 20, 2005, 07:24 AM
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Tucker, Georgia, United States
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Thank you, keep us informed when you have the maiden voyage! tt

(speaks only English )
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