CA 24% extra - ARC
 

Well, here goes my effort at a build thread.....

I ordered a CA extra (24%) from Planes Plus for a "Cant refuse" deal (returned/damaged).

After ordering the plane (almost ready to cover), I started doing some research in the forums. I found that the 24% version was coming out way tailheavy when built by the numbers. The wing area was not as large as expected as well (approx. 880 sq.?). Reports were that it tracked very well (long fuse) but was no 3D machine. My plan then was to keep the plane as light as possible and at all costs, make sure I wouldn't have to add nose wieght.

Here is how it came in the box on June 22nd.

RE: CA 24% extra - ARC
 

Here is what it looked like 10 minutes later....very encouraging....I weighed the airframe just as is in the picture - 5lbs. 1oz.

RE: CA 24% extra - ARC
 

By reading the forums, I realized that I had to extract any amount of grams that I could from that loooooonnnnng tail moment. "Mr. Rudder, I want to introduce you to my little friend, Mr. Hole Saw."

After swiss cheesing the rudder as much as I dared (doing the twist test after every few holes), I went after the elevators as well. With the elevators I was much more conservative and I did not break through the top balsa skin. After the hole saw treatment, the total weight difference was right at 2.0 oz. Not bad really, since the that 2oz. was soooooo far from the cg....about 4X's as far as the firewall to the cg....which would equal about 8oz. of nose wieght.

RE: CA 24% extra - ARC
 

As many know by now, CA instructions are great for mixing epoxy....

The instructions show a cross bar underneath the center of the canopy, in which you are to install a blind nut, then just screw down the canopy/cockpit deck. If so, you will need a screwdriver hole in the top of your canopy???!!! I opted to install a tab on each side, near the back of the deck and use nylon screws from the outside.

RE: CA 24% extra - ARC
 

I have to restate how good the people are at Planes Plus. They gave me such a good deal on just a slightly damaged plane. The damage was contained to a few broken stringers (1/4" sq. balsa) on the bottom of the fuse, and a damaged fiberglass cowl. The cowl had a tear across the bottom which required a bit of 1/2 oz. cloth, but no biggie. I also found a few places where the shipping monsters had their way with the plane. A bit of filler here and there and we are ready to start covering.

RE: CA 24% extra - ARC
 

The motor box comes simply taped together. It's up to you how you go about centering the motor to the cowling, and how to get the distance out to the front of the cowl right. My buddy brought over his new laser level (wide beam for mounting shelves, etc.) and we established a position on the firewall. These new household lasers are fantastic for model building. Anyway, after cutting the motor box back about 1.75", I had the distance close for my YS140sport. Here is a very poor picture of the mounted YS motor....and in the cowl...

RE: CA 24% extra - ARC
 

You will notice, the fuse is not covered yet....(about Aug. 1st). I was undecided about how I was going to run control linkage to the elevators. The rudder would of course be pull/pull. After some debate, the lightest setup for the elevator would be pull/pull as well to a good, high torque, coreless servo in the fuse, near the cg. This servo is mounted on its side up high in the fuse...to be in line with the stab. The rudder servo position was moved forward, closer to the wing tube. The throttle servo found a home near the firewall.

RE: CA 24% extra - ARC
 

After mounting the servos, I had to then run the pull/pull exit locations. This where the laser level again saved the day. We taped/marked the position of the laser from the servo arm, to the location of the control horn looking down on top of the fuse. Then marked with tape with a laser line from the side. Where the two pieces of taped crossed, was where the exit of the pull/pull line would be. Very accurate and simple. Note, the pins in the picture are to keep my ca hinges centered. I also use carbon fiber rod for my control horns (thank you Nat Penton). I drilled an 1/8" hole (carefully) straight through a hardwood dowel hardpoint and ca or epoxy it in place. The nylon eyelets can be ca'd onto the rod later when the linkage and throw is set to my liking. Also note the MK tailwheel....very light. I also drilled some lightening holes in the tailwheel plate as it was very large and thick (1/4", 7 ply).

RE: CA 24% extra - ARC
 

With servo stuff out of the way, the fuse could finally be covered. Added some stripes (copy of Bert Sutton's Cap). The boys seem to approve of the color scheme so far....waiting to paint cowl and pants, then add some stars....

RE: CA 24% extra - ARC
 

Good work Flytexan.
I see that you have read my old thread!

You can save some weight by replacing the heavy aluminum wing tube by a CF. Keep the tube socket included in the kit, the CF tube will fit perfectly.

CA alumium tube: 110g
CF tube: 44g
Weight saving:66g=2.3oz
Go with the Kavan wheels. They are the lightest on the market!

I would not recommand to buy a CF landing gear like i did. It's expensive and there is no real weight saving if you drill some hole in the aluminium gear like you did on the tail.
Mine fly very nice at 12lbs and unlimited vertical with MVVS1.6, Menz S 18x6 7900RPM. Not a 3D monster but a very good IMAC plane
Daniel

RE: CA 24% extra - ARC
 

Thanks Scoubidou....thanks for posting the original thread to give me some pointers.

Well, the trim was added and the cowl and wheel pants were painted to match.....the blue is a shade off...oh well.

Now, for the weigh in.......I am using a digital fish scale (up to 15lbs.) which has been accurate in the past....

Everything except fuel - 9lbs. 10oz. I will double check with another scale when I get the chance to take the plane to work. Right now, though, it feels very light.....lighter than my 11 lb. pattern plane.

This includes: YS140, tetra 16oz. tank, 1650mah Nimh, all servos, tru-turn spinner (lightened backplate), 16x10 apc, dave brown wheels, aluminum axles, mk tailwheel, spyder wire (fishing line) for pull/pull cables to elev. and rudder.

Ran the motor last night. Tint and glue on canopy and we're ready to go.....I hope.

RE: CA 24% extra - ARC
 

Wow, 9lbs is very good! Where is your CG? Did you use a bellcrank for the elevator?

RE: CA 24% extra - ARC
 

Right now, the CG is just in front of the wing tube, but the batt. is also at the firewall. I plane to balance on the tube by moving the batt. further back. Do you fly yours with the CG right on the tube?

The elevators are setup with pull/pull cables to a single high torque coreless in the fuse.

RE: CA 24% extra - ARC
 

MY CG is right on the wing tube and it flies nice. I do not not plan to move it back. It snaps well at that position;)
I had some problems on the first flight because the plane was not balance laterraly. I added 1 oz at right wing tip. Now the nose drop at the stall speed instead of the wing tip stall.


The wing loading is heavy at 12lbs and it's around 31oz/sqft. So, i need some speed to land:D

I am flying that plane to practice IMAC sequences.

RE: CA 24% extra - ARC
 

Nice looking extra. Do you any mix in k.e.?....I was expecting to go to the belly a bit....

I would like to be able to fly this as my backup pattern plane...we'll see how straight it can be trimmed out. Then, there is always sportsman imac as well.

RE: CA 24% extra - ARC
 

Well, the weather here was very nice (houston) and there were no excuses. It flew very well. Lots of power and lots of control authority. I was able to tone down the throws and fly a sequence on the second flight. The downlines want to go toward the canopy a little bit. K.E. is funny....seems speed related. At high speed it seems to couple alot (windy conditions this morning too??) but when slowed a bit to do a nice intermediate sequence, the k.e. is very good and predictable. It might need 3-5% up elev. mix....I'll wait for a calm day to dial that in. Landing was nice and slow with no stall tendency at all.....matter of fact I touched tail wheel first on the the second flight with it crabbed into a slight crosswind....very pattern plane like. I landed prematurely on the second flight as I found that the elevator was suddenly out of trim (needed up). After landing, I saw that one of my spyder wire cables going to the top horn on one elev. was broke/cut by the sharp edged hole on the 4-40 end (ones with the hole) that goes into the clevis. I will either deburr all of these 4-40 ends or try coated steel cable. Does anyone know if the coated cable will cause any rf interference with my antannae running down the inside of the fuse?

Hope to fix cables tonight and fly again tomorrow....maybe get some video tomorrow.

RE: CA 24% extra - ARC
 

Here is a pic of the broken cable....looks like the sharp edge on the 4-40 threaded rod cut the spyder wire. The cable doesn't actually look like it is broken in the pic....but it is....at the end of the loop....frayed and cut.

RE: CA 24% extra - ARC
 

I like my MK bellcrank on the elevator:D

I mixed -5%, +5% rudder-elevator

RE: CA 24% extra - ARC
 

I flew Mark's Extra this morning for a couple of minutes, lucky me....:D

It's really a great flyer. Tracks like a pattern ship. It has an unbeleivable power to weight ratio, and it flies very light on the sticks. With a little mixing, some tweaking of throws, expo, etc...it is gonna be a real winner.

Richard.

RE: CA 24% extra - ARC
 

Richard kindly took video of the extra this morning. This is some clips from the 4th flight...takeoff is just under half throttle...

Go to www.houstonsportflyers.com then to downloads....

http://www.houstonsportflyers.com/ge...id=CAExtra.WMV

Thanks Scoubidou for your input and postings.