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Scale RCM 1/3 Scale Champ Build

TonyHallo

150cc
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3 coats of color, three coats of primer. I think this system provides more shine than Polytone, this photo is from the instruction manual.
 
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TonyHallo

150cc
Finished installing the ailerons today, made four brass 1/8" hinge pins that are retained with cotter keys from DuBro 1/4 scale hinges. The outboard pins slip into a hole on the aileron and are pushed out into the hinge once the aileron is in position. The hinge pocket is larger on the inboard side because the control mechanism is located there on the full scale so the inboard pins just can be installed at any time.

The uncovered wings weighted 2 1/2 pounds each, the painted wings are 4 pounds each. Could have used a little less Ekoprime but not much less paint. In my mind I was thinking 5 pound per wing and 30 pound for the fuselage, so I have an additional 2 pounds to work with.

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Snoopy1

640cc Uber Pimp
Interesting numbers but if I may ask from the numbers you gained 1 1/2 lbs per wing, so what does that work out to be oz/ sq-ft. With this number we can make accurate calculations between your new processes and other products. Thanks.
 

TonyHallo

150cc
The each wing is approximately 18 square foot total, so 1.33 ounces per square foot of covering. Not sure how this compares with other systems, this includes the fabric, Ekobond, screws and washers (3 ounces per wing), finish tape, Ekoprime and paint. Seems like a lot when I compare it to Monokote, but it is scale.

Summary of my experience with Steward Systems;
I started on left wing using information gathered from the Steward System videos. Never gave a thought to looking at their web site for an instruction manual, found it thanks to AKNick. So on the left wing I painted all the wood surfaces with Ekobond before attaching the fabric. This lead to several areas where multiple coats of Ekobond were applied on top which lead to Ekobond oozing through the fabric as heat was applied. I suspect this would not be the case on full scale since the fabric is heavier. The soft white color erasers I purchased at Staples would clean the excess Ekobond. Steward offers an eraser for this purpose, it cost $2.00 by far the cheapest thing there! I plan to but one on my next order.

On the right wing I used a more traditional modeler approach and only a painted the perimeter with Ekobond. I covered the wings with one piece of fabric that was attached to the trailing edge and rapped around the leading edge. The fabric in the open bay areas is filled with Ekobond thinned with water at 3 to 1. I used this to attach the the untreated areas such as the leading edge sheeting as well.

The fabric is filled with the thinned Ekobond and it goes on well, the videos and manual state to cross brush the fabric with a foam brush to work the Ekobond in. This goes well while wet however those places where obstructions are located just below the surface cause problems if over brushed when the Ekobond dries. If a drip happens to land on a spar as example the fabric sticks to spar when pressed down. I found these areas after the first coat of primer. The manual recommends applying Ekofill to these areas to prevent this from happening. If I had read the entire manual this could have been prevented. This problem is not discussed in any video I watched.

The finish tapes are applied with Ekobond, I stated using a chip brush as suggested in one of videos. As always the chip brushes I buy end up leaving bristles everywhere. After the first few tapes I decided to look for better brushes. I bought a pack of artist brushes at Lowes and thought I would just clean the brush after use with water. I thought this worked well, problem is the dried Ekobond embedded in the bristles works it’s way out. Really didn’t notice much until the first coat of primer, where did all these raspberries come from? Next time I will try foam brushes for the tapes or possibly an acid brush, you wipe the tape to remove all excess Ekobond anyway.

Filling the fabric has some confusion. The web site has a pdf Which-Primer-To-Use that suggests Ekoprime is better than Ekofill. The next job will get the first coat of Ekofill then Ekoprime rather than the thinned Ekobond treatment.

The paint is a two part catalyzed poly urethane paint. They recommend a vapor respirator when spraying. The paint is mixed 3 parts paint, 1 part catalysis, and one part water. The first coats are dusted on and a final wet coat. It dries slowly so it takes some time to complete the work, the manual states it is better to wait too long rather than long enough.

All in all I’m happy and will use the product again, water based is much more friendly than MEK.
 

TonyHallo

150cc
This discussion about got me thinking. I have an unfinished BUSA Super Cub, covered with Stits, fake stitches, tapes, sprayed with Poly Brush and a light coat of Poly Spray. I weighted one wing, 3 3/4 pounds less paint. I have no idea what the wing weighted before covering but both wings are nearly the same size, Super Cub 18.7 sq ft and the Champ 17.8 sq ft. So 4 pounds seems about right for the Champ.
I am planning to paint the wing with Ranthane paint. I actually did paint the wings back in 2009 and they fish eyed, ended up removing the covering and start over. Got to the point where I needed to up grade my air system which never happen until last year. I'm sure the wings are completely gassed off after 11 years. The paint is still liquid in the can so I assume it is still ok, don't want to open it just to check.
 

TonyHallo

150cc
Spent last week in Key West so it is time to get back to work. I added 1/8 x 1/4 spruce stringers to the rear cowl area. These were not shown on the plans. I'm planning to make the rear cowl out of .010" aluminum sheet much like the full scale. The only aluminum I could find that was .010" thick was soft temper so thought the extra stringers would help support the aluminum sheet.

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TonyHallo

150cc
I used SeeTemp to make the pattern for the aluminum sheet. The rear cowl is one piece with the split on the bottom of the fuselage. I used to stock up SeeTemp and #11 Exacto blades at the Toledo show every year. I will miss that show for sure. This red colored stuff is several years old, the stuff bought more recently is translucent white colored. The pattern was used to cut out the aluminum sheet. Might just get a photo later tonight of the completed rear cowl, then on to the windshield.

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