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Old Oct 17, 2012, 08:52 AM
Chop it, cut it, bash it
quitcherbitchen's Avatar
United States, CA, La Caņada Flintridge
Joined Jul 2011
4,854 Posts
Quote:
Originally Posted by ww2birder View Post
Build it.... Fly it....Crash it....Fix it....Repeat....Love this hobby.
I try to stay away from the....Repeat. Papa's advice is sound. The watt meter is a must. And If you own more that a dozen(flyable) planes then I guess I am a Crack Pot.
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Old Oct 17, 2012, 09:15 AM
Bay Area Prop Buster
Bluhammer's Avatar
Bay Area CA
Joined Jan 2011
3,796 Posts
When doing mods and upgrades to any plane, you're just rolling the dice without using a watt meter to test the final setup. Why go through all that time and money without really knowing what's truly going on?
Blu
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Old Oct 17, 2012, 09:27 AM
flying is everything
jdm2ner's Avatar
United States, FL, Hollywood
Joined Oct 2010
244 Posts
Quote:
Originally Posted by hillbille View Post
I am using the 11" at factory (non altered) pitch.




Hillbille
what size esc are you using
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Old Oct 17, 2012, 09:49 AM
AMA 884978
hillbille's Avatar
United States, CA, Barstow
Joined May 2007
2,086 Posts
Turnigy Plush 60. I also use a UBEC.

Hillbille
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Old Oct 17, 2012, 10:54 AM
Registered Crasher
United States, TX, Coppell
Joined Feb 2011
2,175 Posts
Quote:
Originally Posted by skypan12 View Post
with the Hacker A30-10XL V2 I am going to use the max watts for that motor is 850watts Max, I will have an CC Ice Lite 75 esc and the HL 4-blade, I will have watt meter checking static watts and if they approach the 850 range I will back the pitch off on the prop till I get to my target of 800 watts or little less.

The 75 ice lite should be enough as I will probably peak in the 60 amp range, but for not very long, going over the specs of this motor with Aero Model Hacker Brushless I was told to pay attention to the watts I am drawing with the 4s batt packs.

On paper this works out staying in the 800 watt range for the prop, and AUW of the ship to make a great combination.

we will see
Looking at eCalc, this is a very inefficient setup (assuming you'll be using 4S), at only 63%. The watts come out to 840, but your flight time is less than 3 minutes (mixed!), on a 2200 battery. Thrust to weight is pretty good though. It'll climb like nobody's business.

eCalc also lists the limit of this motor as being 650W, not 850W, which is interesting.

With this setup, you'll be pulling 71A with a pitch speed of just 85mph. While fast, you can get the same with a lot better flight times.

Playing with the numbers some, you really need to bring the prop diameter down while leaving the pitch pretty high. Lowering the pitch ends up reducing your pitch speed too much, meaning a slower flying plane.

I use an APC 11x9x4 that I cut down to 10". Using that prop with your setup nets you another 45s of flight time, gets the watts down to ~700, amps to 57, and only results in a 1mph slower pitch speed. 70.3% efficiency.

Now, to see even more dramatic results, plug in the numbers for the smaller HL 4 blade prop at 9.5x10x4. You get about 4mins mixed flight time, 54A draw, 670W (which is closer to what eCalc says the limit for that motor is), and a 95mph pitch speed. 72% efficiency.

So, assuming you really want ~85mph pitch speed, lets pitch that prop back a bit and see what the numbers look like. Pitching it back to just 9", you get just 50A (640W) of draw on the motor, 4.21 min mixed flight time, and 87 mph pitch speed. 73% efficiency. The only worry I would have with this setup is that you'd be spinning that plastic hubbed prop at over 10k rpm, which I'm not sure is wise. Maybe it would be better to cut down the APC 11x9x4 to 9.5" dia...
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Old Oct 17, 2012, 12:29 PM
AMA 884978
hillbille's Avatar
United States, CA, Barstow
Joined May 2007
2,086 Posts
Quote:
Originally Posted by jdm2ner View Post
well took her out today after an all nighter trying to get th d-day invasion strips done and let me tell you she looked great. i had one flight and it flew great . second flight she would not make it home. i fried the power25 870 and my eflight 60amp esc using the hobby-lobby 11x10x4 prop on a 3000mah 40c 4s battery. i dont know if using the 4s instead of a 3s had anything to do with it but im back to the drawing board for a motor for this plane. what have you guys been running with this prop? please help!
Invasion stripes can be done in about an hour - if you do them like this.

http://www.bakehead.com/images/Invas...n_stripes.html

The wet towel or typing paper does NOT stick to the wet paint, old paint or the foam so you can keep painting until it is all done. Much faster and quite easily done too.

Hillbille
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Old Oct 17, 2012, 12:44 PM
flying is everything
jdm2ner's Avatar
United States, FL, Hollywood
Joined Oct 2010
244 Posts
thanks hillbile
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Old Oct 17, 2012, 01:13 PM
flying is everything
jdm2ner's Avatar
United States, FL, Hollywood
Joined Oct 2010
244 Posts
well im talking to hobby lobby and asking them what motor and esc to put on this plane. I will let all of you guys know what they say
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Old Oct 17, 2012, 01:21 PM
Shut up and fly
papabatman's Avatar
United States, CO, Firestone
Joined Jun 2008
9,879 Posts
i could tell you if you want it is easy to figure out do you want to run the 4 blade prop? do you want to use a 4s? you need a 600-700 kv motor to work
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Old Oct 17, 2012, 01:27 PM
Is Stateside.......
dav3uk's Avatar
Uk South Wales
Joined Aug 2009
2,187 Posts
4s and stock pitch is going to kill motors, ESCs, lipos and may even melt soldered joints. Its something like a 10 inch pitch.....

on 3s with a G25 870kv, 2700 mah 25c lipos and a 50A ESC she will go vertical out of site and nothing is getting too hot, you will need to bring the pitch back a bit to get it within the motors limits though.

As others have said the prop is not designed for the sort of load a hot 4s setup will put on it, they are sold as electric only props for a reason...........get a blade in the face and it will ruin your day........put a blade in someone elses face and the attorneys will be rubbing their hands together forever..............

If you want to go hot 4s use a 1 piece APC prop

I assume that as you had a BEC fitted the lipo gave up?

Dave
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Old Oct 17, 2012, 01:34 PM
Is Stateside.......
dav3uk's Avatar
Uk South Wales
Joined Aug 2009
2,187 Posts
Quote:
Originally Posted by jtaylor996 View Post
I think either a watt meter, or eCalc would have saved that plane-- forget the BEC.

First, assume at least half the answers to your question on the Internet (even here) are coming from crackpots. YOU always MUST double check as best as you can any advice you get.

All of those components are fine on this plane, just not in that combination. But nobody gives that complete of an answer, so if one pieces it together and assumes it will all work together... without either checking the numbers or actually testing the setup, then you get what you got.

ECalc and the turnigy 7-in-1 meter are both awesome. Please buy.

So success is:
1. Chat here
2. run eCalc
3. Buy stuff
4. Bench test it (to double check eCalc)
5. Enjoy

On the rebuild, no sharpie in the panel lines, please. I've been holding that comment back for days now, but it's 2am...
Why say forget the BEC?

When modding to this degree some backup is always helpful.

Dave
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Old Oct 17, 2012, 02:30 PM
Registered Crasher
United States, TX, Coppell
Joined Feb 2011
2,175 Posts
I just don't think it was the cause of the accident here.
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Old Oct 17, 2012, 02:35 PM
Registered User
Northern IL
Joined Sep 2006
779 Posts
Quote:
Originally Posted by jtaylor996 View Post
Looking at eCalc, this is a very inefficient setup (assuming you'll be using 4S), at only 63%. The watts come out to 840, but your flight time is less than 3 minutes (mixed!), on a 2200 battery. Thrust to weight is pretty good though. It'll climb like nobody's business.

eCalc also lists the limit of this motor as being 650W, not 850W, which is interesting.

With this setup, you'll be pulling 71A with a pitch speed of just 85mph. While fast, you can get the same with a lot better flight times.

Playing with the numbers some, you really need to bring the prop diameter down while leaving the pitch pretty high. Lowering the pitch ends up reducing your pitch speed too much, meaning a slower flying plane.

I use an APC 11x9x4 that I cut down to 10". Using that prop with your setup nets you another 45s of flight time, gets the watts down to ~700, amps to 57, and only results in a 1mph slower pitch speed. 70.3% efficiency.

Now, to see even more dramatic results, plug in the numbers for the smaller HL 4 blade prop at 9.5x10x4. You get about 4mins mixed flight time, 54A draw, 670W (which is closer to what eCalc says the limit for that motor is), and a 95mph pitch speed. 72% efficiency.

So, assuming you really want ~85mph pitch speed, lets pitch that prop back a bit and see what the numbers look like. Pitching it back to just 9", you get just 50A (640W) of draw on the motor, 4.21 min mixed flight time, and 87 mph pitch speed. 73% efficiency. The only worry I would have with this setup is that you'd be spinning that plastic hubbed prop at over 10k rpm, which I'm not sure is wise. Maybe it would be better to cut down the APC 11x9x4 to 9.5" dia...
If I change the motor to the Hacker A30-12XL V2
http://www.aero-model.com/Hacker-Bru...-A30-12XL.aspx which is 700 KV rather than the 900kv A30 10XL V2 do you think that would work better for this set up?

Switching to the APC 4-blade would be a plus as far as safety is concern with a hot set up as you say it is one piece and a little more robust, and it being 11X9X4 and cutting it down to the 10X9X4 would that set up be little better?

I do not have ecalc and run Mac so I dont know if I can get ecalc to work, any input would be helpful on this.
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Old Oct 17, 2012, 02:39 PM
Shut up and fly
papabatman's Avatar
United States, CO, Firestone
Joined Jun 2008
9,879 Posts
nope
Operating Current: 25A
Peak Current:37A
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Old Oct 17, 2012, 02:43 PM
Shut up and fly
papabatman's Avatar
United States, CO, Firestone
Joined Jun 2008
9,879 Posts
look for something this size

http://www.hobbyking.com/hobbyking/s...ner_610kv.html
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