|Jan 26, 2010, 06:35 PM|
Easy "Killer" Whale with Ball Camera Turret in Nose
I'm building a new plane based on the classic EasyStar with a couple twists.
I wanted to drop the Tail Boom and bring the pusher motor center of thrust more in line with the center of lift.
I really like the EasyStar for the efficient wing, great foam and simple launch and recovery. I don't like the way it shoves it's nose down when you add power and the left turn tendency from the torque and P factor. I think the pod being so much higher than the center-line of the wing exacerbates this problem.
I was a little inspired by MyFlyDreams EasyWhale (Skywalker) and used a little imagination on the Easystar.
I made the following cut on the fuselage to drop the pod and tailboom but keep most of the EasyStar intact.
I then Glued a 1" thick piece of Elapor (EPP) foam to fill the cut.
I now have an EasyStar Fuselage that is 1" taller in the radio compartment and the motor pod is much more in line with the wing center-line.
That also gives me a little more room to work in a Ball turret Camera Mount in the nose.
Here is the beginning of the Ball Turret Camera Mount. Using a KX-191 board camera and a HS-65MG tilt servo.
More to follow, comments are appreciated.
|Jan 26, 2010, 07:49 PM|
I never liked the way the Easy Star dives under power at launch.
So, more room, less dive and a ball turrent. Cool.
I can't wait to see it with the turrent on it!
|Jan 26, 2010, 08:05 PM|
If you had a block of it around, it was probably just EPP.
One thing you may encounter though, is that now that your main wing is well
above the horizontal stab, it may cause turbulence over the stab which
can lead to loss of elevator authority or even a departure of the tail (causes
a flick or flat spin). May want to try adding an equivalent spacer to the
bottom of the vertical stab to get the horizontal up closer to even with
the wing again.
|Jan 27, 2010, 02:24 PM|
Thanks for the comments,
Ian, the foam I used was http://www.hobbypeople.net/gallery/115360.asp It was labeled EPP (Expanded Poly Propylene) foam.
I think Elapor is just Mutiplex's trade name for the foam they use. Elapor may have a slight bit of Expanded Polystyrene (EPS) foam thrown to give it a little more rigidity but I think the bulk of it is Expanded Polypropylene. CA adhesive will eat through EPS and Pure EPS Models are not near as durable as EPP.
Regardless the block foam from Hobby People is very similar to it's characteristics to Elapor. I bonds very well with CA to Elapor and it seems to work great as a filler piece.
I appreciate your concern about the Horizontal Stabilizer being lower.
I too am concerned about that as I was also planning on installing flaps which would make any aerodynamic issues more significant.
What I'm betting on is that by lowering the stab I will actually be moving it further from any turbulence created by the wing. Especially at higher angles of attack when it counts the most. I look at a Cessna 172 with a wing that is even higher from the stab than what I'm building.
In the back of my mind I keep thinking there are issues with "T" tail designs at high angles of attack where the wing turbulence blanks out the effectiveness of the stabilizer. In addition having all that prop blast on the tail feathers will pull me out of a hole if I have issues. I'm hoping lowering the stab won't cause any problems.
Rest assured the maiden voyage will be a tense one. I guess that's true with any modified airframe.
|Jan 27, 2010, 02:45 PM|
Ok, so here's how the ball turret is shaping up.
I've got a 3/8" brass tube as the shaft attaching the ball. It is hollow and allows me to run the wires for the camera and tilt servo right up the middle with no tangling.
I made two plastic gears out of 1/8" ABS sheet and cut notches on their perimeter to fit the drive belt. The drive belt is a piece of tail rotor drive belt for a T-Rex450.
The 3/8" Brass tube rotates inside of a brass sleeve that is soldered to the hollow brass support arm.
I cut out two large rectangular "portholes" on the left and right sides of the fuselage below the wing. This is where I will put a 2200mah 3s battery on each side.
In order to reinforce the fuselage around the battery compartments and wing I cut a 1/64" thick plywood stringer and CA glued it in between the fuselage halves.
You can see the nose job on the fuselage and the mounting blocks for the EZ-Ball
I mounted the Hyperion out-runner motor onto a brass plate soldered to a brass tube. I then put a wooden dowel into the tube and bonded it into the stringer and fuselage.
|Jan 27, 2010, 03:02 PM|
That is some ingenious device !!! Serious surgery on the easy star
I would perhaps consider the use of easy glider wings to carry the extra mass and elongate the tail boom for yaw stability.
You can get easy glider wings as a spare from multiplex
|Jan 27, 2010, 04:36 PM|
Netherlands, NH, Edam
Joined Jul 2004
Poor EasyStar, she started out as a nice and slim girl with curves in all the right places, and now she looks like a fat, chubby chick that frequents KFC on a daily basis ...
|Jan 27, 2010, 04:36 PM|
That's a good idea about the EZGlider wings.
I'm putting the 2nd lipo right on the CG. I figgure I'll try it with the EZStar wings first with just one lipo. Then I'll try the 2nd lipo and see how it flies with the extra weight. I've enlarged the stock EZStar Rudder as usual but I can definately see the merits of extending the taill boom. Especially if I go to the larger wing.
LOL Sander -- Well said !! At least the camera will be in her nose pointed away from her voluptuous body.
|Feb 02, 2010, 08:25 PM|
Thanks Martin, I will do my best.
I guess we all know too well from personal experience how quickly the ground can "re-arrange" a lot of hard work
|Feb 03, 2010, 06:39 PM|
There was too much friction on the EZ Eyeball using the brass tube design for the main shaft. This was especially true once I put tension on the drive belt. It would move OK but the pan servo would buzz and hum.
I kept the 3/8 brass tube for the shaft but I used a ball bearing from an old helicopter swash plate in place of the brass sleeve. That was a huge improvement on the smoothness and servo load.
I'm also thinking about moving the Video Tx out on to the wing.
I'm getting a little noise in the video from the ESC and my RC range tests are a little disappointing. I did like the idea of having it all centralized into the fuselage so as not to create asymmetrical drag and weight. It also made the installation a lot cleaner not having to route all the wires through the wing.
I've had good luck on prior planes with the Tx in the wing so I will probably go back to that.
|Feb 03, 2010, 10:53 PM|
Joined Nov 2009
I like your design mods. It's lookin good.
I've been working on a ball turret myself with the same idea of placing it in the nose of my ez*.
I hope you don't mind.. for kicks I painted a design on your plane. I was curious to see what it would look like.
|Feb 03, 2010, 11:21 PM|
Wow Eves !! That looks Awesome
Very dark and Sinister yet in a Free Willy, Eco-Friendly, Save the Planet kind of way.
I'm seriously thinking of incorporating that -- "EZ Killer Whale"
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