View Single Post
Old Apr 06, 2004, 06:06 PM
AMTJIM is offline
Find More Posts by AMTJIM
"Bible Thumper"
AMTJIM's Avatar
United States, AZ, Tucson
Joined Mar 2001
1,924 Posts
This is not an experiment for me, I have done this very sucessfully several times. This Firebat will fly like no other. After we acomplish this build, I am going to build a version with the powerplant in the nose.
.
Here's what I am going to use:
GWS EPS 350 with the "C" ratio(5.33:1)
This set-up provides a wide variety of battery choices according to prop selection. At the low end, 14 oz of thrust can be achieved with this gearbox from 7.2 V which means a 2S lipo can be used. On the other end of the spectrum, for SHORT full throttle bursts a 9.6 V pack or 3S lipo can be used for almost 19 OZ of thrust. Other battery choices are the 2/3AA KAN 650 or a 2/3 A pack like the 600AE or KAN1050, choose you number of cells. This gearbox also provides good speed and response.
Here is a link to a chart for the 350 C performance:
http://www.gws.com.tw/english/produc...system/024.htm
.
This project can be easily accomplished with a 6~8 cell KAN 650 or 6~8 2/3 A cells. The K650 will be OK as a flat pack, but for ease when using a 2/3 A cell, I suggest only a 7 cell pack in pyramid config of 3 on 4, this was very successful before. Lipos are all different sizes, I am going with an Etec 1200 in either a 2s2p or 3s fashion, make sure it can handle the amps your running. What ever battery you choose, try to keep small for placement and under 6 oz, below 3 oz may need a touch of nose ballast. In regards to battery choice, they will all be placed in the same basic area.
.
For ESC, this is your choice according to your current and battery voltage. Again keep it light, a non-brake GWS 100 did fine on 7 cells with the 350 motor, I may go with the C-20 for the higher cell count for use with a 3s lipo. Moutning the ESC outside the plane really helps for cooling.
.
I am going with servos in the size range of the HS-55, this project has had success with GWS pico servos upto HS-81. For what we are trying to accomplish, I suggest HS-55 or smaller.
.
For RX i am only going to use a GWS 4 channel of 300M(1000ft) range.
.
Additional items I will be using are the Robart 1/2A pin hinges for the ailerons, Dubro Micro horns for the ailerons and dubro mirco pushrods in place of the stock push rods. I like to slice the ailerons off, they work much better hinged, you could even upgrade to some FFF ailerons, but the stock works fine. This is just my preference, feel free to use the tape on the ailerons and other stock items.
.
We may run into some additional items that are needed, I will let you know if that happens.
.
When I receive my Firebats, I will start the process with pics and display a little each evening.
AMTJIM is offline Find More Posts by AMTJIM
Last edited by AMTJIM; Apr 06, 2004 at 06:11 PM.
Reply With Quote