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Help!!!! New to electric RC

Old 02-04-2007, 02:11 AM
  #1  
Ed Emmons
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Default Help!!!! New to electric RC

After a 30 year hiatis I have returned to RC. I have been overhelmed by the changes that have occurred during my absence.

I am scratch building a Fiesler Storch, which I plan to power with an electric motor. Wingspan is 60 inches. Flying weight is estimat in the 5-6# range.

Any suggestions regarding motor size, ESC, batteries (no LIpo}, etc., willl be appreciated.

What is the difference between an inrunner and an outrunner motor?

Ed Emmons
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Old 02-04-2007, 05:05 AM
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I went through a similar experience six months ago. An "inrunner" is a brushless motor that spins internally to drive the shaft; an "outrunner" has an exterior case that spins (yes, that's right, the case spins). I'm guessing that a Storch would do fine on 50 or 75 watts per pound so I'll let someone else recommend a motor, esc and battery.

I prefer inrunners to outrunners to avoid dealing with the spinning case.
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Old 02-04-2007, 06:34 AM
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TeslaWinger
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Generally, the inrunners require a gear reduction to run a large enough prop to generate a large volume of thrust at the lower speeds as would be apropriate for a plane with the amazing slowflight capabilities of the Storch.

The outrunners by virtue of their larger diameter and spinning mass have more torque and don't require gear drives if you pick one that will run a prop of the size you require. Expect at least a 10% loss of efficiency due to a geardrive.

The spinning case is not a problem in anything I've ever used one in and the simplicity, light weight and lack of maintenance required is very welcome for the long life and high efficiency they offer.

What size prop do you require? 6 pounds is substantial for a 5 ft slowflying wing!

Love the LE slats and the long travel shocks on this classic!
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Old 02-04-2007, 06:53 AM
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Gee, I've never had an inrunner fail. I use several different windings in a multiplex mini mag and use a direct drive with HUGE props. I have outrunner planes, too, with motor mounts that are designed for them. I believe there are many fine, low KV (high torque) inrunners but concede that outrunners work very well. I don't think "maintenance" is a genuine issue: maintenance of what?
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Old 02-04-2007, 04:34 PM
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Milton
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Originally Posted by Ed Emmons View Post
After a 30 year hiatis I have returned to RC. I have been overhelmed by the changes that have occurred during my absence.

I am scratch building a Fiesler Storch, which I plan to power with an electric motor. Wingspan is 60 inches. Flying weight is estimat in the 5-6# range.

Any suggestions regarding motor size, ESC, batteries (no LIpo}, etc., willl be appreciated.

What is the difference between an inrunner and an outrunner motor?

Ed Emmons

You say from 5-6 lb so lets use the higher number. I don't know the plane but for sports flying 75-100 watts will work, I was flying a 8' wing span plane that weighed 19 1/2 pounds on 2,000 watts and it had very good vertical.
We get watts from volts times amps = watts, Watts = power

So I think we are looking at about 600 watts for your plane, To find out what motor, ESC and batteries we need.

I would use at least a 5 S battery that is 5 cells in series which will be listed on pack as 18.5 volts but fully charged will be 21 volts.
I use 3.7 volts x amps to figure my estmated watts for set up. That is what you can get from good cells under a load.

So we know that we will be using 18,5 volts now to get the amps needed to get our watts. 600 watts devided by 19.5 volts = about 32.5 amps

So now we know we need a 5S pack and a motor that will handle 32.5 amps, go a little high and figure 40 amps.

That tells us we need a ESC that will handle 5S and 40 amps.

With inrunner's most need to be run with gear reduction because most are high KV motors (RPM per volt) Most outrunners are lower KV and can run direct prop placement.

If I was setting it up I would use something in the range of

Outrunner that will handle 40 amps and 5S pack
ESC that will handle 40 amps and 5S
Battery in range of 5S and 3500 to 4000 mAh

You will also need a BEC because most ESC in 5S will not be able to run your receiver.

Hope this helps

Milton
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Old 02-04-2007, 07:26 PM
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Dr Kiwi
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Assuming you want a big prop, turning slowly, for your slow-flying Storch, something like this might be okay.

http://2dogrc.com/ecommerce/os/catal...oducts_id=2101
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Old 02-05-2007, 03:49 AM
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I can vouch for Dualsky outrunners: they are well-made and relatively inexpensive.
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Old 02-05-2007, 02:19 PM
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10% loss of efficiency is excessive. If that is indeed true the gear drive is junk and should be replaced.
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Old 02-09-2007, 04:01 PM
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Welcome back Ed. I jumped back in October since giving it up the early nineties. There are several good forums like this one with lots of info and people willing to help noobs with questions. I am learning quite a bit but stilll overwhelmed. Just keep digging and reading. One area to get very informed about is the care and feeding of Lipo batteries. If not properly used they can pose a danger.

Fortunately I still had all of my RC equipment and radios and only had to buy new batteries. I enjoy building and tinkering as much as flying. I started off with a few slowflyer balsa kits then got side tracked building fan fold Blucor foamies. Haven't done any flying yet other than Realflight G3.5, but having a blast building and tinkering.

Rick
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Old 02-10-2007, 09:49 PM
  #10  
Ed Emmons
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To all of the RC flyers who responnded to my request about electric power for my Fiesler Storch, THANKS.

I had estimated that the finished Storch would weigh 5-6 pounds. That was an uneducatd weight guess. A more conserative estimated would be in the 4 to 5 pound range.

I'm presently wintering in Huachuca City, AZ., and will be retrning to Connecticut at the end of March. I have the elevator, stab, flaps and ailerons are finished but not covered. Both fuselage sides are finished. I'll have to make a jig to hold the sides and fuse formers in place during assembly. The fuselage construction is very compliated.

Ed Emmons
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Old 02-11-2007, 01:17 PM
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flypaper 2
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Ed:
Both E Flight and Himax show the equivalent glow motors in their motor specs. to help pick the right motor. Works for me.:p Im using a Himax HC 50 on a Twist 3 D and works very well. Weighs around 4.5 lbs. using Makita power tools li-ion batts.
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Old 02-11-2007, 04:44 PM
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Originally Posted by Milton View Post

You will also need a BEC because most ESC in 5S will not be able to run your receiver.

Hope this helps

Milton
Let me clarify this. The ESC's built in BEC ususally can't be used with this many cells so you will either have to use a separate radio battery or an external BEC made to regulate such high voltage down to 4.8 or 6 volts for the radio reciever. Some high voltage ESCs don't even have a built in BEC. There are several makers that make switching regulated BECs that can safely and efficiently regulate as much as 45 volts down to 4.8 volts at 5 amps output, enough for the high torque servos of giant scale aircraft. In fact, some IMAC gassers are using these so that they can power the radio with lipos for a weight saving.

A lot of people prefer a two battery system, especially on hot liners where the motor batterys stand a good chance of being blown during a race. You at least still have control of the plane.
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Old 03-14-2007, 09:27 PM
  #13  
ORD2FRA
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Using PeakEff-Pick A Motor

It came up with this:

All Up Weight: 4.50 lbs (14 combinations found)
Battery Config: 4S LiPo (14.0V) >=2400 mAH capacity
ESC Rating: >=28 amps

Motor: Uberall Nippy Black 1812/100 (62g KV=1020)
Prop: APC E 9.0x4.5
Motor Pin: 358.9W Eff: 83.0% Cruise: 48 MPH Static Thrust: 1540g/3.4 lbs

Motor: Hacker A30 28S (71g KV=1140)
Prop: APC E 8.0x4.0
Motor Pin: 343.8W Eff: 84.0% Cruise: 48 MPH Static Thrust: 1293g/2.8 lbs

Motor: Hyperion HP-Z3007-30 (77g KV=1050)
Prop: APC E 9.0x4.5
Motor Pin: 376.7W Eff: 83.1% Cruise: 49 MPH Static Thrust: 1569g/3.5 lbs

Motor: HiMax HC2816-0890 (79g KV=890)
Prop: APC E 10.0x7.0
Motor Pin: 401.5W Eff: 73.8% Cruise: 56 MPH Static Thrust: 1455g/3.2 lbs

Motor: PJS 3D 800-E (85g KV=1006)
Prop: APC E 8.0x6.0
Motor Pin: 394.3W Eff: 80.5% Cruise: 63 MPH Static Thrust: 1226g/2.7 lbs

Motor: BP Hobbies 2908-10 (91g KV=991)
Prop: APC E 9.0x6.0
Motor Pin: 403.3W Eff: 77.5% Cruise: 59 MPH Static Thrust: 1522g/3.4 lbs

Motor: Medusa Research 028-040-1000 (99g KV=1000)
Prop: APC E 9.0x6.0
Motor Pin: 374.4W Eff: 79.0% Cruise: 58 MPH Static Thrust: 1464g/3.2 lbs

Motor: Plettenberg HP 220/15/B16 P14 Frstyle L (99g KV=1193)
Prop: APC E 9.0x4.5
Motor Pin: 398.0W Eff: 71.2% Cruise: 47 MPH Static Thrust: 1463g/3.2 lbs

Motor: BP Hobbies 2915-5 (123g KV=813)
Prop: APC E 11.0x7.0
Motor Pin: 358.2W Eff: 67.9% Cruise: 48 MPH Static Thrust: 1439g/3.2 lbs

Motor: Feigao 380S 34T (3808434S) (136g KV=1161)
Prop: APC E 9.0x4.5
Motor Pin: 324.9W Eff: 70.8% Cruise: 45 MPH Static Thrust: 1316g/2.9 lbs

Motor: Feigao 380S 33T (3808433S) (136g KV=1196)
Prop: APC E 9.0x4.5
Motor Pin: 353.3W Eff: 70.5% Cruise: 46 MPH Static Thrust: 1371g/3.0 lbs

Motor: Feigao 380S 32T (3808432S) (136g KV=1234)
Prop: APC E 9.0x4.5
Motor Pin: 385.7W Eff: 69.8% Cruise: 47 MPH Static Thrust: 1429g/3.1 lbs

Motor: Feigao 380L 34T (3808434L) (176g KV=850)
Prop: APC E 11.0x7.0
Motor Pin: 332.1W Eff: 65.1% Cruise: 46 MPH Static Thrust: 1308g/2.9 lbs

Motor: Feigao 380L 33T (3808433L) (176g KV=876)
Prop: APC E 11.0x7.0
Motor Pin: 356.3W Eff: 64.3% Cruise: 47 MPH Static Thrust: 1375g/3.0 lbs
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Old 03-15-2007, 02:51 PM
  #14  
ron_van_sommeren
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Originally Posted by TeslaWinger View Post
... The outrunners by virtue of their larger diameter and spinning mass have more torque ...
Only diameter gives more torque, spinning mass has no effect.

Vriendelijke groeten Ron
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