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Old 05-03-2012, 08:16 AM   #1
cjsogle
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Default 700E v2 Scale What Motor??

I'm embarking on a new scale project using a 700e v2 barebones kit as a starter. I was wanting some advice on what motor to use. Obviously the stock 700mx would be easiest in terms of fitting or perhaps the new 750mx? My concern is whether these will provide the needed grunt with the extra weight?

Any advice would be welcome.

Thanks in anticipation
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Old 05-03-2012, 04:07 PM   #2
Hank79
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It would have plenty of power, problem is it will rev too high. You will need a lower kv engine for a better scale look and sound. If you go multiblade you will definently need a lower kv engine due to multiblade heads not being designed for high rpm.
There are many good low kv engines out there, Scorpion, Hacker, Xera etc. For a 700 size bird I would suggest as 300/400 range kv engine with the 12 or 11 tooth pinion. This will give 1200-1300rpm with good efficiency on the CC ESC in governor mode. With these particular engines you may also need a custom or adjustable motor mount, KDE have a fully adjustable mount that will fit nearly any 700 size engine on your 700E.
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Old 05-03-2012, 05:06 PM   #3
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Quote:
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It would have plenty of power, problem is it will rev too high. You will need a lower kv engine for a better scale look and sound. If you go multiblade you will definently need a lower kv engine due to multiblade heads not being designed for high rpm.
There are many good low kv engines out there, Scorpion, Hacker, Xera etc. For a 700 size bird I would suggest as 300/400 range kv engine with the 12 or 11 tooth pinion. This will give 1200-1300rpm with good efficiency on the CC ESC in governor mode. With these particular engines you may also need a custom or adjustable motor mount, KDE have a fully adjustable mount that will fit nearly any 700 size engine on your 700E.
Hank, those 11 or 12T pinions are too thing for a 6mm shaft. I lost my EC145 600 size 12S to a 12t Pinion that snapped in half mid flight. I wouldn't trust another 11 or 12T Pinion again. Are those motors 6mm or 8mm shaft. Don't know about the 11 or 12T in 8mm shaft but it could be the same. Two days after mine went down because of a 12T Pinion, another fellow from RC Group lost his to the same Pinion, coinsidence? May be not... Just saying.....
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Old 05-04-2012, 03:55 AM   #4
Andy01
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Make that 3 people, although my 12T 6mm pinion shattered when my 4 blade 600 crashed when the tail drive failed.

You don't need lots of power for scale, so even a 4025 would have enough power. Just find one that gives the right headspeed.

Depending on what scale model and how many blades, somewhere around 1200 to 1400rpm would be a good place to aim for. My Vario Long Ranger weighs 19lbs, runs two 710mm blades, 1350rpm headspeed, and I use a Xera 4030/3Y-470kV motor. It flies scale circuits on around 900W, and hovers with 1100W, so 20-30A is normal - nowhere close to the peak power of a 4030 or 4035 motor. Plenty of power. Xera makes slower motors as well.

Scorpion has a good range but has the downside of requiring regular oiling, which is difficult on a scale heli.

Example;

400kV x 44.4V x 0.9 (Efficiency) x 12T / 112T = 1712rpm at 100% throttle, so 1300rpm would require governing to 76%, which is getting a bit low, but OK.

A 11T pinion would be better, and possibly still OK on Mod 1. Another option may be to fit a 164T Mod 0.7 main gear on your 700, and then your options would open up a bit.

470kV x 44.4V x 0.9 (Efficiency) x 13T / 164T = 1488rpm at 100% throttle, so 1300rpm would require governing to 87%, which is getting a lot better .

Colin
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Old 05-04-2012, 10:41 AM   #5
Cap231ex
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I'm running a Z-Power A50-800 (780Kv) on my stretched 600 to a 700 spinning 700mm blades at 1050 - 1100 with helical 188t main and an 11t helical pinion using a 6000mah 6s pack.

I have to do the Raptor 8t tail pulley mod to be able to run that low of head speed though.
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Old 05-04-2012, 10:54 AM   #6
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Originally Posted by Cap231ex View Post
I'm running a Z-Power A50-800 (780Kv) on my stretched 600 to a 700 spinning 700mm blades at 1050 - 1100 with helical 188t main and an 11t helical pinion using a 6000mah 6s pack.

I have to do the Raptor 8t tail pulley mod to be able to run that low of head speed though.
Is that with a motor shaft of 5mm? .188t mod .7 ?
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Old 05-04-2012, 01:18 PM   #7
Cap231ex
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Yes and yes.
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Old 05-04-2012, 02:05 PM   #8
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Yes and yes.
That's the setup I was looking for before, but I had a HS4035-560kv and it was 6mm shaft, could not find a 6mm pinion helical on mod.7 13T

So I ended up getting a HS4035-500kv 6mm shaft with 15T probably have to go 14T will see.

Will have to remember these setups for future reference. 6mm shaft's are nice but you can't find all the pinion selections....
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Old 05-04-2012, 05:17 PM   #9
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Thanks for the heads up guys.I have been using the stock 12 tooth pinion on the Scorpion 330kv without any issues at moment. The 4035 series engines has a 6mm shafts. I actually have crashed my 700E a few times in pod and boom and never done any visible damage to the pinion, just the main gear. With the 12 tooth iv ran head speeds between 1950-1200rpm reliably. Are you guys sure that this is the pinion that has given you grief because I'm running six blades with reliability at this point. I've had 20 flights so far.
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Old 05-04-2012, 05:46 PM   #10
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Quote:
Originally Posted by Hank79 View Post
Thanks for the heads up guys.I have been using the stock 12 tooth pinion on the Scorpion 330kv without any issues at moment. The 4035 series engines has a 6mm shafts. I actually have crashed my 700E a few times in pod and boom and never done any visible damage to the pinion, just the main gear. With the 12 tooth iv ran head speeds between 1950-1200rpm reliably. Are you guys sure that this is the pinion that has given you grief because I'm running six blades with reliability at this point. I've had 20 flights so far.
I was using the RevCo Hardone 12T Pinion 6mm shaft and it snapped in half.
http://www.helifreak.com/attachment....5&d=1335059410
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Old 05-04-2012, 11:48 PM   #11
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Hi guys, I've got 2 heli's with both the 700 and 600 setup. The 700 is a chaos based
(trex clone) Century Md500e. In order to be as scale as possible, it's running a 5 blade century head in reverse direction (counter clockwise) with the tail flipped to the left. With the tail to head gearing stock, I was aiming for a headspeed in the 1400-1500 range. I'm using 600mm blades to keep the headspeed a little higher and maintain decent tail authority with stock tail blades. I went with a scorpion 4035 330kv motor with a 13 tooth pinion. The stock main gear on the 700 is a 115 tooth mod 1 gear. The 12 tooth or 13 tooth gears are perfectly strong and reliable in mod 1. I run a headspeed of around 1450 in the 85 to 90% throttle range with very good tail authority. My 600 based seahawk is chaos 600 based with a 4 blade head and thin cord scale rotortech blades (love these blades). Also aimed for 1400 to 1450 headspeed. The 600 mechanics have a 164 tooth kde mod .7 main gear. I originally had a hyperion 4035 560kv 6mm shaft motor with a revco 12 tooth pinion. This gave me 1450 rpm with the throttle in the mid 80% range. Fortunately I read Jose's account of shattering his 12 tooth, so I switched the motor to an Align mx700 470 kv
6mm shaft motor. It has a different mount pattern than the scorpions and hyperions and is slightly larger in diameter, but still fit between the widened chaos frames. I did have to modify the mount holes, but it fits pretty well. I'm running a 14 tooth mod. 7 pinion and am getting 1450 rpm at 87.5% on the throttle. Both the setups are running 12s. Hope this helps, and by the way....Hank....your "little bird" is incredible!!! Been
following in on multiple sights....if you need any hints on reversing the tail, let me know. I was able to keep a solid tail pushrod with cut down guides and still fit it in the fuselage. Exits at the top, but not to visible.
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Old 05-05-2012, 02:36 AM   #12
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Quote:
Originally Posted by Hank79 View Post
Thanks for the heads up guys.I have been using the stock 12 tooth pinion on the Scorpion 330kv without any issues at moment. The 4035 series engines has a 6mm shafts. I actually have crashed my 700E a few times in pod and boom and never done any visible damage to the pinion, just the main gear. With the 12 tooth iv ran head speeds between 1950-1200rpm reliably. Are you guys sure that this is the pinion that has given you grief because I'm running six blades with reliability at this point. I've had 20 flights so far.
Hank

Does your 700 run a Mod 0.7 or Mod 1 gear. I would suspect that smaller pinions may be OK on Mod 1 because the gear is bigger (because of bigger teeth);

12T Mod 0.7 = 8.4mm nominal (PCD) diameter, less a 6mm shaft hole = 2.4mm from edge of hole to middle of the tooth, which means there is very little metal between the hole and the root of the teeth.

12T Mod 1 = 12mm nominal (PCD) diameter, less a 6mm shaft hole = 6mm from edge of hole to middle of the tooth - quite acceptable.

I run a 9T Mod 1 pinion on my Atom 500 with a 5mm motor shaft (I think it is 5mm ?), and never had a problem, but even it would have 4mm from hole to mid tooth.

Colin
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Old 05-05-2012, 02:42 AM   #13
Hank79
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Mod 1 Colin, few... you guys were getting me worried lol.
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