Hi,

I am planning to build a twin EDF RC plane.

We have chosen these two EDF but not sure which one to order?

http://www.hobbyking.com/hobbycity/store/uh_viewItem.asp?idProduct=5484&Product_Name=EDF_Fan_Unit_74mm_/_2570kv_/_860g_thrust_w/_Motor

http://www.hobbyking.com/hobbycity/store/uh_viewItem.asp?idProduct=7888


I have found that people have been using 60A ESC for this EDF. Do i need 2 ESC's for these 2 EDF's. Or Can I use one 120A ESC for both of them ?
I want to keep the  weight as low as possible ?

which batteries should I choose to power these EDF's ?

If I order my items through hobbyking, will it be customs hassle free ?
And what precaution do i need to take while ordering ?

Thank You

Quote from: chasni on January 03, 2010, 10:43:06 PM
We have chosen these two EDF but not sure which one to order?

Motor selection is primarily driven by the all-up-weight (AUW) of the model.  You have to have a good idea about the weight of the model before you can reliably do motor selection.

Quote from: chasni on January 03, 2010, 10:43:06 PM
I have found that people have been using 60A ESC for this EDF. Do i need 2 ESC's for these 2 EDF's. Or Can I use one 120A ESC for both of them ?
I want to keep the  weight as low as possible ?

which batteries should I choose to power these EDF's ?

With brushless ESCs, you do NOT want to put two motors on one ESC. Since they are feedback driven, two motors will confuse the ESC, and you will have to spin one of the motors with your hand to get them both in sync and running. So the short answer to your question is that you have to use separate ESCs.  And having 25% higher capacity on the ESC from what is specified in the motor ratings is somewhat of a standard practice.

BTW, there are certain brands/models of ESCs that support this, in case you insist.  But they are generally expensive.

If you go for a 4s lipo, you will get the maximum power from the two motors listed above, but make sure you have a charger than can reliably charge a 4s lipo.

Quote from: chasni on January 03, 2010, 10:43:06 PM
If I order my items through hobbyking, will it be customs hassle free ?
And what precaution do i need to take while ordering ?

Ordering EDFs and batteries should not be much of a problem. You may be asked to pay customs (or not, depending on your luck!). Remember that normal shipping plus customs checks etc would mean 2 to 5 weeks for the item to be delivered, as reported by others.

Thanx anwar...

I have budget constraints so I wanna power my plane with these two EDF's . So, i want to keep its weight within limit so that the thrust provide is enough.
I have read reviews that following EDF provide 800+ grams of thrust at 40A and 15V.

http://www.hobbyking.com/hobbycity/store/uh_viewItem.asp?idProduct=5484&Product_Name=EDF_Fan_Unit_74mm_/_2570kv_/_860g_thrust_w/_Motor

As per your advice i will provide two ESC for these EDF's...

Will one 5000mAh 4S1P 20C Lipo be enough for powering both EDF's ?? I dont need a long flight time around 5 minutes will be enough

A 5000mAH 4s battery is pretty heavy, but it may be OK depending on what kind of plane you are building.

Can you provide some more details what design, size specifications and material you are planning to use in the build ?

At first, I am planning a to build a simple twin EDF plane something like A10 Thunderbird. But later I want to model VTOL with the same EDF's.

One rule of thumb is that you need about about 400watts per KG on the safe side.  Now in your case, there are two motors, so the thrust is spread across both.  Remember that EDFs deliver full capability in a "duct", so figure that into your design.

With this information, and a rough estimate of the AUW of the plane, you can make a motor/battery purchase decision.