stuk_at_work

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Folks,

I was lucky enough to be selected to be one of the Beta testers for this new plane from Airfoilz. The preliminary manual, which unfortunately is not available yet for the general public to see has an incredible number of color photos and drawings to aid in the contstruction, so I will only be posting photos here that will give you an idea of what building this plane is all about.

A link to the product webpage for this plane can be found [link=http://www.airfoilz.com/bearcat/index.html]here[/link]. For those of you who don't want to take the walk, the specs. on the plane are as follows:
[ul][*] Wingspan 32" (Area 210 sq")[*] Length 26"[*] Ready to Fly Weight: 11-13 oz[*] Recommended Power Hacker A20-26M (outrunner 125-150 watts)
[/ul]

Just to give you an idea of what will get posted when, I'll be building in the evenings and uploading photos and comments around noon EST. Questions (that I have answers to) will be responded to as I get a chance to sneak onto RCU during the workday.

Here is a pic. of what the finished plane should look like.

stuk_at_work

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This plane is primarily constructed of Depron, with a fair amount of plywood and balsa. As can be seen in the picture in the previous post, it is somewhat unique in the "foamy world" in that both the fuselage and the wings are "built up". The wing has a true airfoil, and the fuselage is built as depron over a plywood crutch that allows all the electronics to be neatly hidden away. This kit is billed as a "builders kit". Unlike many foamies out there today, assembly is more than just slapping some foam together (gads! There is sanding envolved!). While an elusive bottle of foam safe Kicker last night prevented me from making a whole lot of progress so far, the quality of the laser cut foam and wood pieces should make construction a snap for anyone with a kit or two experience under their belt.

stuk_at_work

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While tempting to just "snap out" pieces from the depron and wood sheets, use a sharp knife to cut all pieces away. Sand any "nubs" off before glueing, as they may interfere with a butt joint later on in the build process.

stuk_at_work

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Here are the two fuselage halves with doublers glued in place. Note that the plywood nose doubler in the 2nd photo is not glued in, but was temporarily located to help orient the placement of the top doubler. You will also notice an approx. 3mm space from the edge of the doublers to the edge of the fuselage sides. This will be important later to form a good joint when the top and botton fuselage foam is added.

Furyflyer2

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Looking good! How do you like the build so far?

stuk_at_work

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So far, it looks like a fairly straightforward build. I haven't really seen any real "difficulty" yet, based on what I finished and the reading ahead in the manual that I've done. While the manual that I'm using is still a "beta" version, the large number of color photos and drawings has made construction so far pretty easy.

stuk_at_work

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Got some more done last night. In these pictures you can see the finished crutch assembly with the fin attached. You will notice a small trapezoid shaped former on the front of the fin. This is glued on first, and helps insure that the fin is upright when it is glued in. The bottom of the fin is glued into the fin by using one side of the fuselage as a guide to position it properly.

stuk_at_work

My Feedback: (111)

The next step in assembly is to join the rear fuselage sides together and to the fin. Masking tape and some rubber banded clamps I picked up at Hobby Lobby make this step a snap. The second photo show the assembled fuselage sides with the canopy/top deck staged for assembly. Note that the canopy and front deck are "pre-curved" to fit in the fuselage without tension. Some of these parts are very similar in shape with only subtle differences between them, so laying them out and trial fitting all the pieces prior to gluing should save some grief.

stuk_at_work

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More parts arrived. Photo is of hinges, servo mounts and control horns that will be included with the kit. The hinges are "commercial" units, the other parts are laser cut plastic. Note that (3) control horns are required for this kit. I suspect that somewhere between the mailbox and the basement one got lost. Oh well. This will be an easy part to substitute if the 3rd one doesn't turn up.

stuk_at_work

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The top deck install was fairly straight forward. No special pictures taken here, I'm sure there will be some later in this thread. I opted to hold off the bottom decking to the end of the build. I figured that this would give me more flexibility if I had to move components around to balance the plane out later since the servo for the elevator and the receiver mount through the bottom of the plane.

stuk_at_work

My Feedback: (111)

The wing construction comes next. The wing is comprised of two halves, each a single piece of depron folded at one end and glued at the other. Fortunately, the folding and gluing is already done for you! A balsa wing spar is used to maintain the dihedral angle and airfoil shape.

Prior to installing the wing spar, the dihedral angle must be sanded to the root of each wing half so that when they are joined there is no "gap". To do this, temporarily insert the provided 6mm depron spacer at the spar location, prop up the wing tip at the designated height, and sand. To make this job easier, I lined up the bottom of the wing at the root with the edge of a table. Once the wing tip is propped up, the top of the wing root will overhang the table. Using the edge of the table as guide, a sanding block make short work of completing this task. As the manual points out, be sure to make a left and right side! Note that I marked both the spar location and which surface is the top on both halves so there would be no confusion once I started the sanding.

One thing that was not spelled out clearly in the manual was how to run the spar through each wing half. After a quick email to AirFoilz, I confirmed that the spar should be perpendicular to the wing root. Installation of the spar requires you to push the spar through the wing, so I used a carpenters square to mark roughly where the end of the spar should end up, and used that as a "target" while pushing the spar through. Using a light to illuminate the wing assembly from the rear makes the spar easier to see as you are pushing it through.

stuk_at_work

My Feedback: (111)

The instructions call for installing the wing by mixing up a batch of 30 minute epoxy mixed with micro-balloons to glue the wing in place and to create a fillet around the wing root/fuselage joint. Knowing how neat I am (not!) with epoxy, I decided on a slightly different route. Since I put off gluing the bottom deck of the fuselage, I had the inside (bottom at least) wing/fuselage joint exposed. Using my special measuring tool (two "E/Z" connectors on a long 2-56 control rod) I aligned the wing and epoxied the wing in place through the inside of the fuselage.

After the epoxy cured, I epoxied the top of the wing in place by gently pushing the fuselage in at the wing root, applying the epoxy at the joint and then releasing the fuselage to "relax" back into place. A quick wipe with alcohol cleared up any residue epoxy before it cured.

Once all the glue cured, I used white, silicon based bathroom sealer to create the fillets. Again, since I'm not the neatest guy, I ran a strip of blue masking tape along the wing and fuselage, leaving a gap where the fillet would be. I ran a bead of silicon down this joint, smoothing it to shape with my fingertip. The masking tape was then removed, leaving a fairly nice fillet.