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Old Jul 18, 2010, 03:15 PM
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Fredriksson's Avatar
United States, KY, Hopkinsville
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Quote:
Originally Posted by nioa View Post
The 35 series Turnigy motors have a 19 mm center-to-center mount and a 25mm center-to-center mount (see the attached image). 4 mm diameter shaft. The shaft on both motors is about 17.5 mm long.
Great information nioa, thanks. Sounds like the Turnigy should be a perfect fit.

Freddy
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Old Jul 20, 2010, 03:54 PM
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nioa's Avatar
Phoenix, AZ
Joined Jan 2008
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Turnigy Motor Measurements

Here are the results of some electrical motor measurements for the:

Turnigy 35-36B 1300kv
Turnigy AerodriveXp SK Series 35-30 1400Kv
Turnigy AerodriveXp SK Series 35-30 1100Kv

I would have loved to have had a Great Planes Rimfire .10 35-30-1250 to test, so if anyone has measured power specs, I would like them.

I will refer to each motor by its Kv number.

Observations: As usual, Turnigy never gives complete specs on their motors so variations are to be expected, especially in terms of kV. I have an older motor (1100) and the kV is not as stated. I think Turnigy has recently gotten better about this.

The motors selected are the closest Turnigy motors I could find to the Rimfire (1250) motor in terms of weight, power, and kV. Great Planes recommends their 1250 motor and a 10x7E prop. One goal is to come as close to the GP power setup as possible. GP states their plane weighs between 2.5 and 3 pounds. If we take the continuous wattage rating of the motor (333 W) and divide it by 3 pounds, we get a watts per pound of 111 W/lb.

I'm not suggesting all the listed Turnigy motors or prop combo's are suitable. The best motor for this application is probably the 1300. But I wouldn't recommend using it with a 10x7E prop. From my measurements, I get 439 watts at 38.9 amps and 147 W/lb with a 9x6E prop (I think this arrangement will be OK). With a 9x4.5E prop, I measured 351.8 watts at 30.44 amps and 117 W/lb. 8x6E looks good too.

I had the 1100, and it powers a Tyro 150, so I am familiar with it and include it only because it pulls a 2.68 lb plane on a 10x7E prop well. It's not a power house, but some may consider this for their SR-22 with a 10x7E or a slightly larger prop (see spec sheet below).

Watts per pound:

If you look at the image of the results, you will see that I have a Watts/Lbs column for both the 2.5 minimum weight, and the 3 pound maximum weight. At this point since I don't have the plane, this seems a good way to get familiar with the range of numbers. Also note that the plane can accommodate a large range of battery weights, so I have to assume that GP states a 3 pound AUW with their recommended 3S 2200 mAh lipo.

Using any one of the available thoughts on power per pound, this one from E-flite is typical:

5070 watts per pound: Minimum level of power for decent performance, good for lightly loaded slow flyer and park flyer models
7090 watts per pound: Trainer and slow flying scale models
90110 watts per pound: Sport aerobatic and fast flying scale models
110130 watts per pound: Advanced aerobatic and high speed models
130150 watts per pound; Lightly loaded 3D models and ducted fans
150200+ watts per pound: Unlimited performance aerobatic and 3D models

So the SR-22, with GP power plant, falls correctly into the sport aerobatic category. Assuming of course, that the motor can indeed handle 333 watts, at a reasonable temperature (say under 160F).

You will also notice that I have a "1/2 Throttle Peak" set of readings for voltage, current, and wattage. Since I don't fly around at WOT all the time, I find that having a 1/2 throttle reading is valuable because it gives a good sense of the power that might be consumed for "average" flying, or cruising. If your lucky enough to have a flight recorder taking power readings, you would be surprised how little power sustained level flight requires.

As a side note -- I find that if you take 15 to 20 percent off of the peak wattage readings, you can get a rough estimate of the average power as a "real world" kind of static reading. For example, on the 1300 motor with a 9x6E prop the 1/2 throttle wattage is 189.8 watts; multiply this by 0.8 (20%) to get about 152 watts. If you look at the meter, while running the motor at this throttle level, you will see the rapidly changing numbers will average around this 152 watt level. "Close enough" as they say.

Another side note -- Temperature; To use the 1300 test as an illustration:

Resulting temperature in room with an ambient temperature of 81 F, and a relative humidity of 45%. (Temperature measurements were made with a infrared temp probe; motor at the mount as close to the bearing as possible; ESC, the hottest spot.) Motor and ESC running for 1 minute at 200 watts:

Turnigy 40A Plush: 125F ESC and motor temp of 123F

Turnigy 60A Plush: 103F ESC, and a motor temp of 119F

A 44 degree difference of the 40A ESC to ambient air doesn't sound that bad, and it isn't, if your flying around in 50 to 60 degree weather, but these figures are with direct open air-flow. The fuselage and cowl air-flow restrictions would most likely result in higher temps. I mention this consideration only because in Phoenix, I sometimes fly in temps as high as 105F. Add 44 degrees minimum to that, and you'll see that cooling is a very important consideration. In this case, since I already have the 60A controller, I would go with that, in spite of the slightly higher weight. If you can keep your electronics under 150F (65C), they will definitely last longer!

Obviously, all power readings are static and limited. They will off course, change dynamically in the actual aircraft.

Hope this is helpful!

UPDATE: RimFire data added see post #44.

The attachments have been removed from this post and updated. The updates can be found in post 44.
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Last edited by nioa; Jul 30, 2010 at 09:31 PM. Reason: New Rimfire data added.
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Old Jul 20, 2010, 09:50 PM
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Very excited about this plane. Ordered it today. Should be coming in on friday. I went with the Electrifly .15 (35-36-1200),Electrifly 45 esc, the recommended servos for the wings and HS-65HB's for the rudder and elevator.
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Old Jul 22, 2010, 08:34 AM
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Outstanding information nioa. Thanks for taking the time to get, correlate and post the data. Have you decided which set-up you will try first? My thoughts would be to go with some good pitch speed. This plane, with its wing loading of 19-23 oz/sq. ft., will have a stall speed of 22-24 mph and will need a pitch speed of around 55-60 mph.

Freddy
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Old Jul 22, 2010, 11:57 AM
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nioa's Avatar
Phoenix, AZ
Joined Jan 2008
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Freddy, thanks!

One thing that concerns me about the numbers is that the power requirements for the 1300 and 1400 are very close.

I think the stated kV's are wrong (not really that surprising). Oh, and I had to tighten up the hex screw on the motor shaft on the 1400, as the bell started to separate. If anyone buys a Turnigy motor, ALWAYS tighten up the hexes, use lock-nut, and give the bearings a shot of 3-in-1 oil. This stuff is supposed to be done at the factory, but I think these things are all made on a Friday!

With the information I have, I think I would start with the 8x6E and the 1300.

Freddy, I would be interested to see what MotoCalc has to say about the whole thing.

Some people reading this may be wondering why not just use the RimFire .10? I've have two other RimFires and I like them, they are good motors, and they have a warranty! But, I always like to try other things, so If you don't like messing around, go with the RimFire. Superem, going with the .15, that's the Spirit!

Nick
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Old Jul 23, 2010, 09:41 AM
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Here is some info from MotoCalc based on my input. I am not sure how close the kv, Idle Current and Motor Resistance constants are for the motors. I always try to find reliable data from the manufacturer or other sources but sometimes I have to guess a little. Here are some comparisons I put together a few weeks ago for myself comparing the Rimfire motor to the Turnigy 35-36B 1300kv. One of the props on the comparison is a 3-blade prop but none are the 8x6 prop. The real SR22 has a 3 blade prop. Also, there is the same comparison with the Turnigy with a 8x6 prop. Consider this to be a fourth column on the other comparison sheet. Finally, I have a file showing the opinion of this plane with the 8x6 prop.

Freddy
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Old Jul 23, 2010, 01:43 PM
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nioa's Avatar
Phoenix, AZ
Joined Jan 2008
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Freddy, the Motocalc info is interesting. In Summary:

Turnigy 35-36-1300
My actual test with an APC 8x6E: 11.63V 31.04A 363.4W
MotoCalc prediction APC 8x6E: 10.3V 21A 215.6W

That is quite a difference in wattage!

One factor may be that the kV on the 1300 is much higher than stated (hence, having to prop down so much). The original power system (RimFire .10 1250kV) is designed for a 10x7E prop. If anyone has a Rimfire .10 motor, I would like some power readings on it -- Initial voltage, voltage, current, and peak wattage.

I think with this motor and the 8x6E, the power system for this plane will be OK, but others buying this motor should do their own power testing to make sure that they are drawing about the same amount of power as the Rimfire system. It would be nice if I had more of these Turnigy motors to test, to see if they are the same, or if I got one that was mislabeled/mis-wired.

Thanks again Freddy, and in advance to anyone with RimFire power measurements!

Nick
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Old Jul 23, 2010, 07:43 PM
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Just found the review online at YouTube:

Electrifly Cirrus SR22 Turbo Review - Part 1 (6 min 47 sec)


Looks great!!!
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Old Jul 24, 2010, 08:47 AM
Eggs @ Tea
Dover DE USA
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man, at the end of that video, not a good venue to land that plane, wrongo in my book
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Old Jul 24, 2010, 03:33 PM
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nioa

I agree, that is a big difference. I did check and the Internal Resistance and No-Load Current constants both came directly from HK. The No-Load Current was at 7 volts.

Freddy
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Old Jul 25, 2010, 06:56 AM
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Well I'm done. Took her out this morning for the maiden. Lets just say it didnt go as planned. Got disoriented and now she's stuck in a tree. For a 50" plane, she is very small. If you blink it gets lost in the sky.
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Old Jul 25, 2010, 08:39 PM
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Sorry to hear about the maiden mishap. I hope you are able to get the plane back. Someone earlier in this thread mentioned that this white plane was hard to see in the air.

Freddy
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Old Jul 28, 2010, 05:37 AM
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Quote:
Originally Posted by N227CT View Post
We flew ours both yesterday and today. It flies great but really seems to fly like it has a heavy wingloading. It's not a lead sled, but just seems a little heavy. With that said, there were no weird tendencies during landing configuration and is pretty easy to fly. Very fast with the rimfire .10 motor with straight up verticals til out of sight if we let it. My son built it in about 2.5hrs and it has Hitec 65's, Rhino 2250/40C 3S and a TB 54 ESC. He said the only thing he didn't like were the decals which were ridiculous to put on. It really looks scale when flying. The white all around also is relatively hard to see compared to most of our planes so keep it in close. Very pleased with the kit!

John
For the couple minutes I flew it, I did notice the same as mentioned above. It likes speed to stay up.
The stickers were annoying but the most frustating was installing the servos and extensions. I almost smashed the wing in half I was at it for close to an hour for one wing I ended having to make an incision in the wing to pull the extension out.
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Old Jul 30, 2010, 09:26 PM
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nioa's Avatar
Phoenix, AZ
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Turnigy and RimFire Motor Specs

I was given a .10 Rimfire motor for testing:

Here are the results of some electrical motor measurements for the:

Turnigy 35-36B 1300kv
Turnigy AerodriveXp SK Series 35-30 1400Kv
Turnigy AerodriveXp SK Series 35-30 1100Kv

and the Great Planes Rimfire .10 35-30-1250

Please see post 32 for observations and conditions of testing the Turnigy Motors. Data collected is shown below in the image and down-loadable as a PDF. The information here is the same as in post 32, but with the RimFire data added.

The 10x7E prop and the RimFire .10 are a great match for each other (see the data). If you go with a Turnigy motor (or other motor for that matter), the RimFire specs with a 10x7E prop are what you want to get as close to possible to.

Again, the data presented for the Turnigy motors is just for analysis. I am not suggesting that all the prop and motor combination's are suitable. If you look at the data, it appears that the Turnigy 1300 with a 9x6E (limit WOT) or 8x6E prop may be the most suitable combo. But remember, that is for the motor that I have. Your Turnigy motor may have a different kV (or other characteristics) that may change the propping. You have to test the prop and motor with a wattmeter to be sure.

Hope this is helpful!
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Old Aug 01, 2010, 03:15 PM
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I hope GP comes out with a larger version, 1/4 scale would be nice.

Tim
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