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View Full Version : Prop for Gentle Lady with E-Flight 480


Franny
01-09-2007, 07:59 PM
Hi All,

I'm trying to decide on a motor to electrify my Gentle Lady (2M) and I'm looking at the E-Flight 480. It might be a little bit much, but I bet with the right prop it should do well here in the Colorado air. Any Ideas on a prop? I will be powering with a 3S Lipo 1300mAh-2200mAh depending on weight. Also, they make two flavors of the 480 - 1020kV and 910kV. The 910kV version can handle a continuous 20A and I bet with the CC 25A ESC would do well. All I need is a start on the prop. I want to use the Graupner CAM folder, but I should probably get the size locked down first. I use a 10/6 on my E-Flight 400 motors and that works well, so I was thinking 10/8 or 11/8 maybe?

Any thoughts?

Thanks,

Franny

flyranger
01-14-2007, 02:21 PM
I'm using the eflite park 480 on my Cleveland Air Racer which weighs in at about 2lbs. It draws 25amps using a 10x7 apc prop. Had to use a CC35 esc to keep from overloading the controller. For batteries, I use either a chinese 3000ma 8c or a 2200ma 15c. Get 15min flight times (sport flying - not full out all the time).

Franny
01-14-2007, 05:22 PM
Thanks Flyranger. I was wondering about the battery size too... Your Air Racer really is nice! I remember it from your posts. I bet it is super fun! I am currently working on a Goldberg Shoestring conversion (.40 size) and can't wait!! Love those old style racers. Such style!

Thanks,

Franny

flyranger
01-15-2007, 05:25 PM
You are welcome. I completed my 2m electric sailplane, which I will name "Miracle". Pics attached. Have done the maiden and trimming flight, but high winds and rain have kept me out of the air!!

Franny
01-15-2007, 06:39 PM
What kind of power system are you running? I only see two motor wires... I hope my GL comes out ander 1.5 Lbs too...

Franny

flyranger
01-16-2007, 03:13 AM
In order to balance with the 2.1oz eflite Park 400 outrunner in the nose, I had to place the Castle Creations CC25 ESC as far foward as possible. What you see in the pic is the battery connection wires. Here's a couple of pics of the "trial balance". Since this is my own design, I have to be careful that I don't end up with a plane that will not balance by just moving the batt forward or back. I'm using Eflite S-75 micro servos and a FMA Direct 5 channel receiver.

Franny
01-16-2007, 04:40 AM
I'm curious... how close did you come with that method? I never seem to get close until I'm just about done and even then the covering can throw things out a bit. I usually cram everything forward and lighten the tail as much as possible...

flyranger
01-16-2007, 12:07 PM
This technique for balancing is borrowed from the free flight builders of the 1920's and 1930s. Since I'm usually building something from my own drawings, I'm always in uncharted territory. Before I do much more than lay out and cut the fuse sides from balsa (for thermalling sailplanes I just use 1/16in hard balsa), I need to know if the "nose moment" (distance from the spinner to the center of gravity) is long enough to get a balance with the "tail moment" (distance from the center of gravity to the end of the tail feathers). I also include the tail feathers, which are usually the "built up" variety to keep the weight down. This model is a V tail which allows less mass in the tail than a conventional cruciform stab and rudder. I used 3/32in balsa that I cut into 1/4in x 3/32in sticks to frame it up. I joined the V like a wing, using a carbon fiber rod and an aluminum joiner bent for the required 145 degree angle, CA'd to the sticks and tied using dental floss. You can see that it leaves a little "bump" in the picture, but I didn't want to weaken the structure more by completely hiding it in the balsa stick. How I come up with the required area and angle of the two "ruddervators" is subject for another post. This is my second attempt at this 2m design. The maiden flight on the 1st attempt was not pretty and resulting in balsa splinters!! The wing survived, but the fuse tail feathers were too small and the angle wasn't acute enough to allow the kind of control I want in a three channel plane. I use 1/4in grid graph paper to draw the design to build up over. I scan the design using a letter-size scanner into a graphics editor (Paint Shop Pro) which I use as a cheap CAD program. The two ruddervator pics have to be printed out and joined with tape, but you will see what I mean. I use the CA easy hinges cut into 1/4in strips for the control surfaces. Hope I'm not boring you with all this detail, I am so frustrated about not being able to fly right now due to the weather!!! As the build continues, I keep checking the balance. For pushrods, I use the DuBro Micro pushrod system with the 047in wires (keeping things light) and usually mount the servos just aft of the center of gravity. I use the Dubro Micro2 control horns.:D