Glow to Electric Conversions Discuss glow/gas conversion to electric here.

Can I get some informed suggestions please?

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Old 04-21-2004, 10:40 PM
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Longarm
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Default Can I get some informed suggestions please?

I dont have the MotorCalc Program and have no experience at all with the large electric conversions so I need some helpful, informed recommendations.

Those of you that have the MotorCalc Program, If you want to plug in the below listed information, I would be very greatful.

I am converting a Hangar 9 P-51 (60 sized) with an AXI 4130-16 motor, I will be using 24 GP3300 Mamp cells (Cant afford LiPos), I have the Hacker Master 77 Opto ESC, and an Ultimate BEC. My estimated all up weight will be very close to 10lbs, +/-.

My request for information is what prop will give this setup the most power. The AXI information table says that a 14/10 prop will draw 41.5 amps and put 975 or so watts to the prop. This is with 24 1700 Mamp cells that I think are NiCAD. I dont know if the higher Mamp batteries will increase the amps, or the watts to the prop because like I said earlier, I have no experience with the large setups, I am just getting started into it.

When you view this, please give me your two cents worth, I would even take only a pennies worth if that is all you have. .........(127 views/ 2 replys)----> that kills me.

Thanks ahead of time for your replies.

Longarm
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Old 04-22-2004, 08:00 AM
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Matt Kirsch
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Default RE: Can I get some informed suggestions please?

Unfortunately, Motocalc does not work well with the outrunner motors. BTDT. Luckily, the figures at modelmotors.cz are actual test numbers, and are very close to reality.

According to the AXi website, the 4130/16 will draw 49.1 Amps with 24 cells and a 14x10 prop.

Don't take the view-to-reply ratio personally. First, people don't know whether they can answer or not until they read it. Second, when you ask a highly technical question, not many people can answer. Third, it's better to say nothing than all than to give bad advice. Fourth, after somebody's answered, people come back to view the replies. All that pushes up the view-to-reply ratio. Would you rather people replied with, "Howard Stern Rules!" or a personal insult?
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Old 04-22-2004, 10:06 AM
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Greg Covey
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Default RE: Can I get some informed suggestions please?

There are additional factors to consider here so there may not be an obvious answer until you test things out yourself.

First, you should buy yourself an Astro Flight Super Whattmeter if you don't already have one. You really need to verify current draw unless you have previously seen your particular setup.

Second, each plane design has an optimal prop size and pitch. My recomendation would be to use the largest size you can get away with and still have proper ground clearance. For example, perhaps a 16x8 on 20 cells would be a better choice. You will get more thrust from the larger prop and drop 1/2 pound in weight from your 24 cell setup. Remember that my 15x8 3-blade prop is equivalent to a 16x8 2-blade prop.

Finally, other factors like throttle management, desired performance, flying skills, and component longevity all play a part in your choices. The bottom line is that your current setup will fly the P-51 well and you may just need to fly it a few times before you start to fine tune setup variables.

Good luck!
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Old 04-25-2004, 09:49 PM
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Longarm
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Default RE: Can I get some informed suggestions please?

Matt, I see you point, no on the Howard Stern Rules or the personal insult.

My plane is almost ready to go. I had a setback with one of my 12 cell packs. I was letting my friend use them separately in his 81 inch Antic yesterday. The first charge on a pack went well. It flew his Antic for a good 9 minutes with over half of the flight aggressive throttle. The other pack, when plugged in, shorted, and began to smoke. Luckily he had not closed his swinging front hatch/door and begun to set the screws. Yanked the pack out and no damage to his plane. Returning the pack tomorrow for a new one. I did a static thrust test Friday night. Man that setup has the juice. It will fly with authority, I am sure. I just would like more of it. Starting out with the 14/10 prop.

More details to follow. Flight could be as early as one weekday afternoon, but will probably be next weekend.

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Old 04-27-2004, 06:43 AM
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Darrell B.
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Default RE: Can I get some informed suggestions please?

Longarm,
Going with the numbers on the Model Motors sight, your 14/10 prop on 24 cells should give you in the range of 88mph. Not to shabby, if you don't mind the slower speed the 16/8 will deffinately give you a better climb out.

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