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02-20-2006, 11:57 PM | #1 |
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Help in the setup - plane is not rolling
Hi
So i still try to figure out what is the main problem. My plane a kind of Piper like, has wingspan of : 59 and rope of 10.5. The weight is 5.5 lbs. I'm using a apc 11x9 propeller, with a ESC: Phoenix CC 80. And with an AXI 4130/20. So i have 2 lipo pack now , 2x 3s4p rate at 6000mha 12c max. That i plug in parallel. So the motor turn and it's was way underpower to flew. At full speed it can't roll on the floor. .. So : Is my setting in the esc are wrong ? , Do i need to put the pack in series ?, or i mostly need 1 lipo pack: TP 6000 3s3p ? or even 2...? Many thanks : |
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02-21-2006, 12:11 AM | #2 |
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I am: Mike Gyger
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http://www.rcmodels.ca/product_info....products_id=56
I'm new to electrics, but if I'm reading the specs at the above link right, your way under voltage. at 3s your turning your prop at around 3500 RPM. If you run your packs in series (someone else, please jump in here) you'll turn at around 7000 RPM. I'm not sure how to prop with the electrics, but I'm sure someone will jump in. Hope this helps a little Mike |
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02-21-2006, 12:33 AM | #3 |
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power needed
I have just re check the manual.. 2 sheet of paper.. of my Castel Creation 80. And i can't go over 4s, so i will be stick at 11.1 volt. parallel the pack
Maybe it's the pack.. Also, i can't go more than 11 inch for the prop. more i will not be able to take off or land. |
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02-21-2006, 01:07 AM | #4 |
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Alright. My knowledge is limited but I'm not over my head yet.
You will need to change something in order for this to work. Either you need a higher kv rated motor (to turn the prop faster on the lower voltage), or get an ESC that will handle the voltage required (and run the motor at less than efficent loads) I'm learning on the go here, but I'm starting to understand how the AXI's work. Something like the 2820-10 would be more along what your after I think. On a 3S battery, your prop speed will be around 10,000 RPM with the prop you want. This is 3 times faster than your current speed (if my math is correct) Your ESC is way oversized for this, as the set-up should draw less than 30 amps. Don't rush out in dispair though, as I may be out to lunch. While we wait for other, more informed people to wake up, have a look at this chart http://www.flyingmodels.org/motortest/index_e.htm It's a good set of data on different motors. Good Luck Mike |
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02-21-2006, 07:14 AM | #5 |
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MotoCalc
Hi,
If you are flying electrics, you need to use MotoCalc to find out how your plane will perform, or for suggestions on how to make it fly better. This is a Canadian software “what if” product for electrics and will help you a lot. First, go to the Motocalc web site and get the 30 day free download at: http://www.motocalc.com Now that you have Motocalc, I'll try and give you some help to get started. I had problems at first, and perhaps this will get you started a little quicker. For first use, bypass the start-up Wizard when it first starts, and enter in all your information in manually. You can enter the information from the manufacturer's specs or from the menus. The Wizard will be useful after you get familiar with to the program, or you don’t have the motor information - try it after the next time you start up the program, and let it pick the best motor battery combination for you. If you can't find a battery pack exactly like the one you have, then select a similar battery pack and enter in the specific information for your pack. Example, I'm using Kokam 1500's LiPo's, and they were not in the list originally so I would select another LiPo manufacturer, and then enter in the differences and save this under any battery name I chose. Once you have all the information entered - push COMPUTE REPORT and it will display a list of the flying characteristics / specifications from the lowest diameter prop/pitch to the highest. This list can be very confusing – as a starter, Watts-In and Amps are used by experienced electric flyers. However, thrust can also be very useful and will be a good starting point for beginners without doing any calculations - just look at it in the analysis for the most, thrust then check the battery amps and see if your battery can give you those amps. As a suggestion, enter in your information, select a range of props (such as DIAMETER 8 to 12, PITCH 4 to 8 ) and then click on COMPUTE REPORT. You will then get a list of the flying / motor specifications for each propeller. Double click on the line that looks the most promising to you - at first, just pick any one to start off with and double click on it. This will give another screen showing the Watts, Amp draw, Thrust etc. for that specific prop. At the bottom of this screen is another button called OPINION, click on this and read through the analysis - to me, the most important is the last section of the AERODYNAMIC NOTES. This will describe what performance and aerobatics you can expect from a plane, motor and prop you selected - it may be described as having trainer characteristics to doing any aerobatics. You can also check flying time, a useful exercise is to move the slider to 3/4 throttle and check the flying time - usually it increases flying time dramatically. Here are a few basics: Direct drive (no gear box) take smaller props and need to run at higher RPM Larger props with large gear ratios can give more thrust with smaller motors and will run prop at lower RPM Higher amp draw (can be controlled by propeller size) means more power but less flying time Increasing batteries (number or capacity) add weight and require more power to fly Note the discharge rate of your batteries, this rating is called "C" - example if you battery discharge rate is 8C and your battery is rated at 1000mah(or 1 amp), it can discharge at 8000mah(or 8amp) and have this current available for motor use Remember, the above should just get you started and may be confusing at first. Play with this for a while, then come back and ask specific questions. I'm sure we can help. Hope this helps. Fly4Fun, Wayne Miller |
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02-21-2006, 11:12 AM | #6 |
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I am: Grant S
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The CC 80 will handle from 5-20 cells or in your case a 6s pack if you disable the bec on the esc.To disable you cut the center wire on the esc where it plugs into ch #3 in your receiver and you have to run a separate battery to run the receiver
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02-21-2006, 07:56 PM | #7 |
RCC Supreme Contributor
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Dude.
Your motor is designed to spin a 16 -18 diam prop with 6-8 lipo cells. At 11.1 volts your motor should be spinning at 3386 rpm. at this rpm with an 11x9 prop you should be getting a whopping 0.5 lbs of static thrust onan aircraft that weighs 5.5 lbs. Negative thrust to weight dont work.This motor should be on a 90 size plane like a funtana for 3d or a very large high wing type aircraft at 22 to 29 volts. 6 cell 22 volts = 6771 rpm with a 18x12 equals 15lbs of thrust follow canhos's advice with a 2820/10
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02-22-2006, 12:38 AM | #8 |
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Ok class is done
Ok,
i have check Motocalc. That's very powerfull. So directly i figure out that it will be the best to use : an Axi2826 - 10 with Tanic 2150 at 11.1 V config but with 2 in parallel. If not i got all the time : Power trouble, over heating. I think pack like the Thunder power 3s2p 4000mh can be use without any problem.. And last, with again a 11x6 prop. Also, i can use my Phoenix80. ( i have it and it can be use without any problem) Of course, i try different type of the Axi line, the 2826 and the 2820. The 2826/10 seem better than the 2820/10. but 2820/12 seem the best and a big gap between the stall speed and the flight speed. haalala ... too much. But i know that was a lot of question about that.. another hint ? And many many thanks for your answer. that's awesome. |
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02-22-2006, 12:46 PM | #9 |
RCC Supreme Contributor
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Before you settle on a battery do some wing loading calculations. Electric comes with a ton of variables. Still like any plane it comes down to wingloading. the lighter the better no matter how you fly or what you fly. Half a pound will make a large difference. Electric is also a vicious cycle. the bigger the motor the bigger the batt and the more weight = worse performance. You also need to decide how you intend to fly and what kind of flight times you want between charges. A bigger battery does not neccisarly mean more flight time and can reduce performance. Electric motors also run bigger/ higher pitch props to take advantage of the motors torque. The best is to forget what you know about glow, this can lead to a less than stellar airplane.
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02-22-2006, 12:52 PM | #10 |
RCC Supreme Contributor
I am: Wayne MIller
Join Date: Aug 2004
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Glad you found MotoCalc useful
Hi,
I'm glad MotoCalc was able to help out. I must admit I found it difficult to use at first, but that is why I listed what to do in my previous post, to get you started. It takes a lot of guess work and LAR (Looks About Right) out of electrics and their power systems. Glad I could help. Fly4Fun, Wayne Miller |
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