Air-Wolf-4U

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Hi All!
I am interested in powering a plane that I am building by electric. I am new to the "electric arena" and need some advise as there seems to be a lot of options!
First I am building a plane that is a lot like a Giles 60. It will weigh about 12 pounds complete (I fibreglassed it so it is a bit heavy) and I was going to put in a Saito 100 4-Stroke. I am going to put it on Floats so I will need a bit extra of power and I am at a loss what to do.
Second; can anyone reccomend what motor, speed controller, gearbox and prop that I need?
I was told that Axies makes some good motors and direct drive at that...would this be a good idea?
Should I even be looking at electric for this size plane and motor? Is it worth it?
Any help and advice would be great as it would be nice to eventually be 100 percent electric. I am thinking no fuel to buy, no fuel to clean off, no starter, power panel and accessories to bring to the field...Wow!

Thanks again in advance for any help and suggestions that you have!

Dwayne

Matt Kirsch

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If you wanted an objective opinion as to what you should do, this isn't the place to ask for it Biased? This forum? Naw!

Any plane can be converted these days. It's just a matter of money. What you need to provide is the specifics on the airplane, such as a firm weight estimate, and some dimensions to give us an idea of the overall size of the airplane. Also, what kind of flying you plan on doing, and how long you'd like to do it (i.e. flight duration) will be helpful.

FWIW, this plane sounds like a real porker. High wing loadings require high power loadings and expensive lithium polymer packs to keep the weight from getting totally out of hand. It won't be cheap, that's for sure, but neither is a Saito 100.

E-Challenged

I am jumping into .40 glow size Dynaflite fun scale P51 and P40 conversions for the challenge of it, not because it is cost-effective. You can pick up a great used glow engine for $100-200 depending on size and 2 vs 4 stroke. If you go to electric you will need at least $300 worth of motor and speed control plus $300 for three 14-18 cell Nimh packs or one Li Poly pack to get the equivalent performance of the glow engine. You will need a charger and probably a power supply for another $250. I bought a NIB geared AF Cobalt 25 from a guy on ebay for $100 and a 16cell Sanyo 1950FAUP NiMh pack to try .40 size electric conversions, already had an AF 110D charger and a 12 volt supply that I use on parkflyers. It really isn't true that you make a one time large investment when getting into electrics, cells and motors can go bad, you still can crash, you may want to upgrade after initial choices. Another factor is that there aren't as many experienced large electric flyers to get worthwhile guidance and used equipment from at the typical R/C flying field or clubs. Lucky we have RC Universe and E-Zone to get help from .
If you can afford to spend a 800 to a 1000 dollars and can get the proper information to select the right quipment and building and operating techniques, and you don't mind the spooky lack of motor noise, go for it! At least there is no post-flight cleanup required and repairs aren't made more difficult by fuel soaked remains.

Air-Wolf-4U

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Hi Matt!
Thanks for your input!
Well you wanted some more details...I weighed everything and it looks like it will be 8 pounds with the motor and servo's (Just not the batteries). The wing area is 140cm long by 24cm wide. The plane body is about 36 inches long. The plane looks a lot like the Funtana 40 but just a bit larger.
I was looking at the CP3300 mah batteries and the hobby shop suggested 16 of them with the Axis 4130/16 Motor.
Does this sound like a good package if I am doing aerobatics? I am not doing 3d but like power to do most other things? Any Idea of how long those 16 batteries might last per flight?
Any suggestions would be greatly appreciated!

Thanks for your help!

Dwayne

Air-Wolf-4U

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Hi Matt!
Thanks for your input!
Well you wanted some more details...I weighed everything and it looks like it will be 8 pounds with the motor and servo's (Just not the batteries). The wing area is 140cm long by 24cm wide. The plane body is about 36 inches long. The plane looks a lot like the Funtana 40 but just a bit larger.
I was looking at the CP3300 mah batteries and the hobby shop suggested 16 of them with the Axis 4130/16 Motor.
Does this sound like a good package if I am doing aerobatics? I am not doing 3d but like power to do most other things? Any Idea of how long those 16 batteries might last per flight?
Any suggestions would be greatly appreciated!

Thanks for your help!

Dwayne

Longarm

My Feedback: (1)

With batteries, add another 2lbs, 4 ounces. that will be close to a 10&1/2 lb plane with not much wing to hold up that much weight. What is the total wing surface area in sq inches? My guess is that you will have a wing loading of around 37 ounces or more to the sq foot and that is ALOT, especially for a 3D type plane.

My P-51 weighed in at 10lbs 11 ounces ...wing surface of 745 sq inches. Wing loading of 33 ounces per square foot. I was using the AXI 4130-16 with 24 GP3300 cells.

My two cents.

Longarm

Air-Wolf-4U

My Feedback: (2)

Thanks for the advice!!!
So true so true! Yes I am finding out that Electric has so many variables that it can get really confusing...yuk! I am still unsure as to what to do but I will keep hacking away! The largest thing that is turning me away right now is the fact that I need about 24 cells and that will weigh a lot. If I go Li-Poly...really expensive! I do not even know if the 24 cells will be enough. The moter says that at 24 cells it will drive a 16*8 Prop at 7000 rpm at 28 Amps...Sound like enough to fly a 60 size plane at 10 pounds and 500 square inch wingspan?

I will keep asking questions though...Thanks!

Dwayne

Air-Wolf-4U

My Feedback: (2)

Hi Longarm!
Wow...so many choices eh? You have the exact motor and battery configuration that I have been looking at...sounds good! The only thing holdimg me back is that fact that the Axi 4130 data that I have says that using 24 cells would draw 49.1 amps (14*10Prop)...may I ask how long your batteries last? If I am figure this out right that should almost be 4 minutes exactly at full power...is this right? Also; that is about 3 pounds of batteries...right?
May I ask how you would say the power of your Axi compares to a glow engine? At your configuration would it be near a 70 Four Stroke?

Thanks for your help!

Dwayne

Longarm

My Feedback: (1)

Hey,

Sorry about not replying until now, I have been out of the loop for a few days. My flight duration with the way I fly is between 9 and 10 minutes with the 24 GP3300 cells. According to advice that I recieved when I was asking these same questions, you take your amp draw and divide it into you total amp hours of your battery. Example, at half throttle, which is where I keep it most of the time and have plenty of power, I expect that I am drawing around 20 to 22 amps.
3.3 divided by 22 = .15, then multiply that number by 60 minutes... .15x60= 9 minutes

The setup compared to a Saito 100 is equal to the power, or more. You will be surprised at this motor. With the right propeller, it will pull some serious thrust. The problem is the battery weight, which is not a problem if you have a big plane that is a scale flyer, like what I have. If you want to get into the serious 3D, I think you will need to get some light Lipos. The cost is up there, but if you really enjoy this hobby and want to go electric, I would go with the new lighter batteries. The new higher discharge batteries, 15C to 20C will let you use less batteries. Instead of a 6S4P, now you can use a 6S1P or a 6S2P.

I am waiting on a shipment of batteries that will be 6S2P with 2550 milliamp batteries. The 2P will make it a 5100 milliamp setup. The weight of the new battery will be 22 ounces. 1lb, 6 ounces. That will reduce my battery weight by 2lbs, 2ounces........Now that is what I am talking about.......!!!!!!!!! That will drop my wing loading to around 25 ounces per sq foot.

The weight of 24 GP3300 cells with connectors comes to 3lbs and 8 ounces.........that is alot of battery weight.

Your wing loading will be 48 ounces per square foot if you come in at 10.5 lbs with 500 square inches of wing. That is way too much.

If you went with lighter batteries, your wing loading with a 8lb plane would be 36 ounces per square foot. That is still up there for 3D applications.. What is the plane supposed to weigh with the glow setup?

http://www.lcrcc.net/thrust_calc.htm

You can get an idea of your thrust with the above link....16/8 APC prop at 7000 rpms = 154 ounces of thrust.....

I hope this information will help you and if I can add anything else, please drop me a line.

Longarm,

[email protected]