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Old Feb 16, 2013, 04:23 PM
Not as Good as The Kid
Aeroplayin's Avatar
South Pasadena, FL
Joined Sep 2009
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Quote:
Originally Posted by bryansifsof44 View Post
The 4330 is 560g or 19.75oz all up weight of the motor. I wouldn't push the motor past 3150W peak. BTW, Chris only recommends 2600-3000 watts for the 78" Extra so I think 3150W should be plenty of power for the 78". Nothing like Tom's setup, but on the lower end of Chris's recommended all up weight. In comparison to gas my 4hp on the 4330 is more then the 3.85hp of the O.S. GT33 or the 3.7hp of the DLE30 and the 3.6HP that EME 35 says in their specs. I am interested to see the performance of the DA35, but most I am almost sure I wouldn't go gas until 50CC and that probably still will be electric.
Maintaining the mathematical relativity, the 78 with the 4330 on 2x 6S 3300 will come in at about 12.18 pounds. At 250 Watts per pound, that's 3044W, which I think is a safe power level for the motor. On 12S, that's 68 Amps on the relative 3.72v per cell, and 5.4 minutes on 2x 3300mAh batteries, in relative comparison to the 6.2 minutes at 13.5 pounds at 3375W. That's 48 seconds less flight time (13%).

Considering that this is a conservative estimate, over 6 minutes is a high probability. It is still relatively less than the 10S 5000 setup but 1.33 pounds lighter.

If we go a bit further, and look at relative wing cube loading and aircraft performance rankings, we find that the 12.18 pounds brings the WCL under 8, and this WCL influences the performance rankings in a positive way.

So the question is, will Ken recommend a 20x8 prop on 12S with the 216Kv wind, and can we go to something like a 202Kv with a 21x8 on this motor?
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Old Feb 16, 2013, 04:26 PM
Yin & Yang
Liberty10's Avatar
United States, VA, Sterling
Joined Jul 2011
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I had heard that the gas version will not be out for awhile. Possibly not until after the DA35 is tested. Not sure if that is true. I was not looking at electric with real seriousness until this discussion. Now if I really could double up even a 4000 6S since I have a few of those anyway it makes the idea of the 78(87) much more appealing. I do like electrics allot and there was the whole storing a gas engine in the house thing I was going to have to deal with. Still will some day since 50CC or larger are where I'd like to get to in the future. Still 7 minutes is't as long as I'd like it isn't that bad either. I'd really like to hear more about the motor(s) that could handle 12S.
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Old Feb 16, 2013, 04:58 PM
Team Twisted!
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United States, CA, Hercules
Joined Dec 2011
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Regarding a gas plane smelling....I keep mine in my living room and it doesn't stink up the place like I thought it would. I can only smell it if I'm putting my face within 3 feet of plane.
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Old Feb 16, 2013, 06:11 PM
On loan to Texas
Ohio AV8TOR's Avatar
United States, TX, Benbrook
Joined Oct 2005
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Quote:
Originally Posted by hone1er View Post
Regarding a gas plane smelling....I keep mine in my living room and it doesn't stink up the place like I thought it would. I can only smell it if I'm putting my face within 3 feet of plane.
Same with mine that spends most of it's time in the dinning room that we don't use. If I take the cowl off I can smell it but even my wife (with the sensitive nose) does not smell it.
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Old Feb 16, 2013, 07:04 PM
Yin & Yang
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United States, VA, Sterling
Joined Jul 2011
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Thanks guy,
Real good to know that it doesn't smell up the place. I drew up plans for a large conditioned workshop out back but haven't had time to walk them through zoning and permitting yet. We need it bad though because we have too much stuff. George Carlin was right. I fill up all the room I had with stuff so now I need more room so I can get more stuff
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Old Feb 17, 2013, 04:33 PM
Not as Good as The Kid
Aeroplayin's Avatar
South Pasadena, FL
Joined Sep 2009
7,248 Posts
We also never had a problem with the gas smell once we drained the on-board tank. On the other hand, the filler tank is another story. Leaving it in the car/van/truck/SUV or bringing it in the house will be a mistake because of guilt by association.


Regarding cell count and weight, you can set up any plane with a 6S 30C 6600mAh battery, 2x 4S 30C 5000mAh pack, a 2x 5S 25C 4000mAh pack, or a 2x 6S 30C 3300mAh pack, all for about the same weight, give or take about one ounce.

You can also set up any plane with a 2x 5S 30C 5000mAh pack, or a 2x 6S 40C 4400mAh pack, all for about the same weight, give or take bout a half ounce.

The capacities I listed in the two comparisons will deliver about the same flight time, and the same Watts, on virtually the same prop diameter, as well. In each instance, the setup with the 12S (2x 6S) will require less current (Amps), which means less heat, and more efficiency.

The key is, of course, getting the motor Kv correct with each setup. You can't use the same motor with the same prop and just change the battery packs. I think that this is one of the main reasons why we tend to talk about Ken and subsonicplanes.com because matching motors to needs is so easy to do with a guy like Ken around.
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Old Feb 17, 2013, 04:37 PM
bryansifsof44's Avatar
United States, AK, Anchorage
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Not to mention the good CS and cool running bad a** motors.
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Old Feb 17, 2013, 05:06 PM
Not as Good as The Kid
Aeroplayin's Avatar
South Pasadena, FL
Joined Sep 2009
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It never ceases to amaze me how cool the Motrolfly motors come down after beating the pizz out of them in the Florida heat.

Something else to remember is the trade-off between prop size and RPM. This is critical in making the decision between gas and electric. The best way to think about this is. do I want a gas setup where I can swing a 20x8 prop to 7200 to 7400 RPMs to achieve a ten minute flight time on a 12.2 pound plane with a 1225 wing area, or would I rather have a 22x10 prop turning 6800 RPMs for 6 or 7 minutes with the same wing area at 13.4 pounds?

A 19x8 prop spinning 7500 RPMs will produce about 20 pounds of static thrust, 2112 Watts (2.8 HP), and the pitch speed is about 57 mph. The WCL is 7.85, and the power to weight is 173 Watts per pound.

A 22x10 spinning 6838 RPMs will produce about 26 pounds of static thrust, 3550 Watts (4.7 HP), and the pitch speed is about 65 mph. The WCL is 8.63, but the power to weight is 265 Watts per pound.

I didn't provide this information to draw a conclusion, but to illustrate the comparisons. You have to fly both types of setups the way you fly to appreciate the difference. There is a big weight difference here, but there is also a big power difference. If you like to fly low and slow 3D, and occasionally find yourself out of position, the pull-out power the bigger prop provides at much lower RPMs is something you learn to appreciate, or even rely on. Id hate to be in full stall, four feet off the ground, at the wrong angle of attack, and have to rely on a 19 inch prop to quickly force enough air over my control surfaces to change my attitude while at the same time pull me from the scene of the imminent crash.

I think I'm going to wait until I know I can swing at least a 21x8 prop on a gas engine in the 78 before I go that way... 22x8 would be better,
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Old Feb 17, 2013, 05:20 PM
VOLTS > AMPS
stgdz's Avatar
United States, MN, Buffalo
Joined Jul 2011
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This one popped up when I was browsing HK
http://hobbyking.com/hobbyking/store...ess_Motor.html

Looks like a decent all around motor for smaller planes and maybe a quad. Granted it is hobbyking
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Old Feb 17, 2013, 08:16 PM
Not as Good as The Kid
Aeroplayin's Avatar
South Pasadena, FL
Joined Sep 2009
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I can only imagine what bearings they have in there for $15.

400W motor... the Omega 103g was a good one. Had it in an old 3DHS SHP on 3S with a 13x6.5 APC to 480W and about 46 to 48 ounces, all up. I still have one of those motors brand new.... I bought three and had two in SHPs that I sold last year.

I think it was $39 and change when I bought them. They survived me and Tom, and they are still going, the last I heard. They use Japanese bearings and from my experience, I'd have no problem buying one again, but not at the price they're asking now. I'd rather have a Motrolfly.
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Old Feb 17, 2013, 11:13 PM
lost in the addiction of flyin
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Canada, BC, Kelowna
Joined Dec 2009
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e-flight power 60 should take 8s right? 400kv
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Old Feb 17, 2013, 11:24 PM
Smokin out the pits!!!
HELLFIRE989's Avatar
Kelowna, BC, Canada
Joined Dec 2008
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Quote:
Originally Posted by furballll View Post
e-flight power 60 should take 8s right? 400kv
Product Specifications
Type: Brushless outrunner
Size: Replacement for 60-size glow engines
Bearings or Bushings: One 6 x 15 x 5mm Bearing, and Two 6 x 12 x 4mm Bearing
Wire Gauge: 14
Recommended Prop Range: 14x8 to 16x10
Voltage: 18.5 to 28.8
RPM/Volt (Kv): 400
Resistance (Ri): .06 ohms
Idle Current (Io): 2.70A @ 10V
Shaft Diameter: 6mm (.24 in)
Overall Length: 62mm (2.40 in)
Weight: 380 g (13.0 oz)
Overall Diameter: 50mm (2.00 in)
Diameter: 50mm (2 in)
Length: 62mm (2.4 in)
Continuous Current: 55A
Maximum Burst Current: 65A (15 sec)
Cells: 1624 Ni-MH/Ni-Cd or 57S Li-Po
Speed Control: 60A brushless
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Old Feb 17, 2013, 11:30 PM
Smokin out the pits!!!
HELLFIRE989's Avatar
Kelowna, BC, Canada
Joined Dec 2008
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Quote:
Originally Posted by furballll View Post
e-flight power 60 should take 8s right? 400kv
Not sure Todd. You may want to email eflite to be sure. I would think it could handle it but the specs rate it for a max of 28.8v a full charged 8s setup is 33.6v even 7s is 29.4 volts
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Old Feb 18, 2013, 12:34 AM
bryansifsof44's Avatar
United States, AK, Anchorage
Joined Oct 2011
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Quote:
Originally Posted by furballll View Post
e-flight power 60 should take 8s right? 400kv
First of all the motor is 380g eflite motor is 100g (3.5oz) heavier then the 280g Motrolfly 4315-480 that I am using and 88g heavier then the recommended MKII. I've had my batteries as far back as I could go on the Edge and not the Extra for neutral. IMO, with out lead in the tail balance would be impossible
Usually when a spec is given for the prop it is for the lower number is for the higher voltage the motor is rated for, so in this case on 8S you would use a 14x8 or a 15x6 the higher end of a 16x10 would be used on the lower end voltage rating in this case 5s. It has a collet style adapter unlike the bolt on style of the Torque or Motrolfly.
IMO, unless you already have this motor spend $20 more on a motrolfly 4315 and have it wound to what battery you want or save $5 and go with the new Torque MKII and run a 15x8 or 16x7 on 6S. If you already have it you will be fighting CG problems without lead if you intend to fly 3D, its a bummer to have to add dead weight to a plane, especially a 3D plane. Hope this helps.
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Old Feb 18, 2013, 01:46 AM
lost in the addiction of flyin
furballll's Avatar
Canada, BC, Kelowna
Joined Dec 2009
802 Posts
ya i already have the motor and i am running a 18x8 3 blade on it with 6s right now. its on my modified night flying plane that i rebuilt last year. not intended for 3d at all as its a protege, i still can get it to hover at full trottle but would like a bit more power to make it more fun on floats. as for weight the plane was an arf prot that was damaged pretty bad and i rebuilt the front very light and need all the weight i can get to not be tail heavy(wish i had put it on a bigger diet before i covered it) so the heavy motor is not an issue.

changing the motor is one of my other options but i have a chance of picking up a hobbywing high voltage 120amp at a pretty good price and i can use it in the future too after this plane.
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