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Old Apr 11, 2011, 09:07 PM
Total newbie
United States, TX, Burleson
Joined Mar 2011
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What would YOU put in this? (and other questions)

I'm not trying to have you guys do my homework for me. What I hope I'm doing is having you, the teachers, put the equations on the board so I can learn it easier. I've done a whole lot of reading over the last 3 weeks and I have some ideas, simply, don't trust myself. I'd hate to burn up a plane over something I thought I was doing right and wasn't.

What power components would YOU put in this? And why? I really need a couple of you guys to show me why you chose what you chose and the math behind it.

ESM ME-109 "EMIL" (Doesn't have to be this plane specifically, but I have my eye on it. Along with the optional retracts)
Wing Span: Approx 73"
Weight: 12 lbs
Radio: 6 chnl. 8 Servos
Engine: .91 to 1.50 4-cycle - Or equivalent 2-cycle Gas Engine: 26cc

Motors mindboggle me. There's just to many to choose from.

ESC's and external BES's I've narrowed down to Castle Creations, Dimension Engineering and Medusa. If there are others out there as good (so I hear) as the three I listed, could ya send me a link?

Other questions:
I have noticed that many of you use 11v batteries. Why? Why not 14 or 18 volt batteries?

Honestly, I feel like a real dolt. There's just so much to think about and remember. Any help is greatly appreciated
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Old Apr 11, 2011, 10:27 PM
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rick.benjamin's Avatar
USA, OR, Damascus
Joined Apr 2004
4,043 Posts
You want to electrify.
This is the plane?
http://www.esmmodel.com/inc/Enproduc...?productid=198
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Old Apr 11, 2011, 11:03 PM
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rick.benjamin's Avatar
USA, OR, Damascus
Joined Apr 2004
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I gather information and write it down.
I went to
http://homepage.mac.com/kmyersefo/sitetoc.html
to get to "Electric Power Basics"
http://homepage.mac.com/kmyersefo/e-basics/e-basics.pdf
Page 15 has a chart labeled "watts per pound"
"Sport flying: 75-100 watts per pound" x 12 lbs
12 x 75 = 900 watts
12 x 100=1200 watts

I used TurboCAD to size a 3-view for 73 inch wingspan
the wing area is 404 x 2 = 808 sq inches
scale prop is 21.5 inches.
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Old Apr 11, 2011, 11:41 PM
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rick.benjamin's Avatar
USA, OR, Damascus
Joined Apr 2004
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I go to a motor vendor to view the specifications.
Power 90 "for sport and scale airplanes weighing 8 to 13 pound"
http://www.e-fliterc.com/Products/De...odID=EFLM4090A
Power 110 "for sport and scale airplanes weighing 9 to 15 pounds"
http://www.e-fliterc.com/Products/De...odID=EFLM4110A
Power 160 "for sport and scale airplanes weighing 12 to 20 pounds"
http://www.e-fliterc.com/Products/De...odID=EFLM4160A

The 110 looks about right. Weighs 490g (17.5 oz)
Needs
85A HV brushless ESC
8S–9S Li-Po or 24- to 32-cell Ni-MH/Ni-Cd
17x8 to 19x10 prop (I would start with an 18 inch prop)
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Old Apr 11, 2011, 11:45 PM
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Fourdan's Avatar
Antony (France)
Joined Sep 2003
2,791 Posts
Hi

I suggest you read this thread
http://www.rcgroups.com/forums/showt...136470&page=25
particularly post #368
Scorpion Calc wizard suggest a "generic solution"
Voltage, Kv, prop
Then you are free to select a Scorpion motor, close to the suggestion, or any other brand

Louis
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Old Apr 11, 2011, 11:45 PM
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USA, NV, Caliente
Joined Mar 2009
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Quote:
Originally Posted by Barbosa2 View Post
I have noticed that many of you use 11v batteries. Why? Why not 14 or 18 volt batteries?

Honestly, I feel like a real dolt. There's just so much to think about and remember. Any help is greatly appreciated
I wouldn't use 3s (11V) in that, or anything at the moment. I would be looking into 12s (45V) systems and about 2kw of power handling. This means you are looking at the HV controllers of around 50A, and something like this http://www.scorpionsystem.com/catalo.../S-5525-170KV/
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Old Apr 11, 2011, 11:54 PM
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Canada, MB, Niverville
Joined Apr 2008
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My TT seafury is in the same weight class as this and i am running an eflite power 110, CC 120hv esc, CC bec pro and running on 9s. 8s works very well also. Have been using a 15.75x13x3 apc prop.
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Old Apr 12, 2011, 12:07 AM
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rick.benjamin's Avatar
USA, OR, Damascus
Joined Apr 2004
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You will need a wattmeter and a tach.
The 110 wants to see 32 to 36 volts (8s-9s)
Depending on the prop load, it will draw up to 65 amps
This ESC will handle the large battery
http://www.rctoys.com/pdf/Phoenix-HV-110-User-Guide.pdf
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Old Apr 12, 2011, 06:44 AM
Total newbie
United States, TX, Burleson
Joined Mar 2011
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Quote:
Originally Posted by rick.benjamin
I gather information and write it down.
So do I. I have nearly 10 pages of a Word document so far. Thanks for the two websites. I'll be reading them tonight.

So, there's three(?) recommendations for Scorpian motors and one for E-flite. Got some more reading there.

I have a Fluke, but no tach. Any recommendation for a tach?

Quote:
Originally Posted by gewiens
i am running an eflite power 110, CC 120hv esc, CC bec pro and running on 9s. 8s works very well also.
What battery manufacturer do you use?

crypto666 - I wasn't suggesting to use an 11v 3s in that plane. That was under the "other questions" department...*grinnin*. I was merely curious as to why so many people use 11v batteries. Is it the type of plane or the weight of the plane most people have that would use them? Or have larger volt batteries not caught on yet?

Quote:
Originally Posted by fourdan
Then you are free to select a Scorpion motor, close to the suggestion, or any other brand
Why Scorpian? See, this is like me building a prototype muscle car. What engine should I use? A Hemi? A corvette ZR1 engine? A Maserati MC12? Etc. Well, too many to choose from. Three people like Scorpians...but why over all the other brands?

And I'd like to use a 3-blade prop. That'll throw off the electronic choices as well, I think.

Man, it just ain't like the old days when one could walk into the neighbour hood hobby shop and ask a few questions. Makes me glad there are discussion boards like this.
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Old Apr 12, 2011, 07:25 AM
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Canada, MB, Niverville
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I'm running 4000mah 45c nanotechs from HK. I can get 10mins flight time no problem and that's running the 3blade. Plane is closer to the 14lb mark and on 8s i have yet to need full power and it hauls.
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Old Apr 12, 2011, 07:28 AM
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Fourdan's Avatar
Antony (France)
Joined Sep 2003
2,791 Posts
Hi Barbosa
The Eflite 110 is announced to : weight = 490g ; Kv = 295 rpm/V
The closest Scorpion is the S4035-250 weight 467g ; kv 250 rpm/V
But you have also good Dualsky (2dogRC website : http://www.2dogrc.com/)
XM6350CA-12 weight 470g Kv 310 rpm/V
XM6350EA-12 weight 470 g Kv 280 rpm/V (new improved series)
Regards
Louis
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Old Apr 12, 2011, 08:19 AM
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Ken Myers's Avatar
Commerce Township, MI
Joined Aug 2001
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Calculated with 16x12 prop.

Motor weight range 500g to 760 grams for use at http://www.rc-book.com/en/
for selection Outrunner motor

Kv dependent on number of cells used.
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Old Apr 12, 2011, 08:53 AM
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Canada, MB, Niverville
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I looked back in my posts and this was my results on static test. APC 15.75x13 3 blade on 8s. 77.85amps and 2380 watts. Also, i am using the CC bec pro on it to use with the HV esc.
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Last edited by gewiens; Apr 12, 2011 at 11:58 AM.
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Old Apr 12, 2011, 11:46 AM
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Joined Mar 2009
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Quote:
Originally Posted by Barbosa2 View Post
I have a Fluke, but no tach. Any recommendation for a tach?

crypto666 - I wasn't suggesting to use an 11v 3s in that plane. That was under the "other questions" department...*grinnin*. I was merely curious as to why so many people use 11v batteries. Is it the type of plane or the weight of the plane most people have that would use them? Or have larger volt batteries not caught on yet?

Why Scorpian?

If you get a castle ESC, get the ice series and use the data logger for RPM, it is close enough. Although tachs are pretty cheap these days.

The reason so many people use 11.1V Lipo is because of the market.

Why scorpion? Because they make great motors and the price is decent.

I would strongly suggest working to keep your current lower than 100A, but check out the price of controllers and see for yourself. The cost of a 50A HV is less than half of a 110-120 HV. Also, running lower currents you will have better efficiency, cheaper batteries, and in general less problems IMHO. The only draw back is more cells to charge, but this is a minor issue. It also allows more flexibility when you get into higher cell counts, you can up your power by simply inserting an extra cell without having to change everything else.

BTW, castle controllers can be run beyond their label. For example, the factory cutoff on a ICE75 is 105A. I have run a 75 up to 120A for a few seconds without issue, it would probably go longer.
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Old Apr 13, 2011, 06:54 PM
Total newbie
United States, TX, Burleson
Joined Mar 2011
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Thanks for the help, guys. It was....ummmm.....helpful...*chucklin*. I still have a lot to think about.
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