Old School Model Works: Raven ducted fan jet

[Michael]

Not in sequence.

Previously, I didn't glue on my wings to the dihedral braces nor the center-wing section/box. Good thing!

Dave and I, and others, were perplexed by the airfoil-shaped 3/32" deep openings in the wing center section. Apparently, although not in the instructions, the wing is supposed to be inset into these spaces. I cut the area at the rear of the opening to accept the trailing edge (I could have cut the trailing edge too), and carefully recut the opening and/or sanded the root wing area to fit.

I'll make sure there's adequate spacing so that the wings will fit when covered later. I will glue this section together after the parts are covered. It's just easier to cover this way.

[davidk]

Not in sequence.

Previously, I didn't glue on my wings to the dihedral braces nor the center-wing section/box. Good thing!

Dave and I, and others, were perplexed by the airfoil-shaped 3/32" deep openings in the wing center section. Apparently, although not in the instructions, the wing is supposed to be inset into these spaces. I cut the area at the rear of the opening to accept the trailing edge (I could have cut the trailing edge too), and carefully recut the opening and/or sanded the root wing area to fit.

I'll make sure there's adequate spacing so that the wings will fit when covered later. I will glue this section together after the parts are covered. It's just easier to cover this way.

I don't have the talent to cut a trailing edge shape into a panel, so I opted for cutting 3/32 off the trailing edge.  I would have preferred to glue it a rib width over, but there you go.

Thanks for talking about the covering again.  One of my wings fits perfectly... tight... but that's no good.  I need room for covering... so I'll do that now.

[Michael]

Not in Sequence.

Going back to step 51, for the wing center box. There is a gap between the bottom plywood sheet and the box sides. I simply filled it in with scrap balsa.

[Michael]

Step 73 is incorrect in the instructions.

The tabs on the former must be cut off (they're in the wrong position), and the former must be glued in position but flush with the top of the side sheeting.

See the photos here.

[Michael]

Step 76 asks for the nose landing gear mount/block to be mounted to the F1-F1A and F1B plywood former.

This is not a difficult task, especially for builders who have done this many times before. Remember, this kit is intended for experienced builders.

I've shown how this step is done for anyone who hasn't done it before. The photos are self-explanitory. Note the the drilled holes must be wide enough to fit the T-nuts; I used a 5/32" drill but. The T-nuts are pushed in from the back of where the mount is to go (the t-nuts technically go on the forward face of the former). Once pushed into the plywood, I applied thin CA to the wood to hold the t-nuts in place. It is imperative that no glue gets onto the threads of the t-nut.

I test-fitted the former (with the mount installed) in place, and noticed that there was not quite enough clearance for the landing gear to come through the lower plywood platform (part TR1), so I enlarged the whole a bit.

[davidk]

I made some adjustments that helped me with my build.  Contact me if you'd like them.

[Michael]

Placement of F4 and F5 formers. Official photo is wrong, mixing up balsa and plywood F4 and F5. The placement as shown in my post 33 above is correct.

Plans are correct, also showing diagonal stick angles down lower than horizontal 'spine'.

Also instructions do not indicate that 1/4" strip be glued to upper forward inside wing-saddle. It should be done (by) now.

[Michael]

Step 81 has 2 plywood strips P1 glued to each other to form one unit ( a double for each side) and glued in place.

I had to cut a notch in one plywood strip so it would fit nicely. The gap in front is for the fan-front to fit. See photos here.

Step 82 incorrectly asks for part P2 to be glued down. This is wrong. It must be part P3.

[Michael]

After step 82, I cut out the temporary cross beams because I felt it would be easier to install the fan inlet sheeting and fan exhaust sheeting without them. I test-fitted the fan unit.

[Michael]

Step 83 explains how to install the fan-inlet sheeting. Seeing as I used up most of my 1/16" sheeting incorrectly when sheeting the wing, I used one of the shorter sheets to do the inlet sheeting. (I still have one 24" sheet to do the fan-exhaust-sheeting later.)

I used a slightly different method for this step.

I carefully cut and fitted a piece of light cardboard into the area to be sheeted, and made a slightly oversize template. I made 2 pieces.

I soaked them with Windex, and when pliable, carefully bent them around some epoxy tubes and taped them until they dried.Then I glued one in (with CA) to half of the diagonal 5/16" square pieces and to half of F4. Then I added, as needed, more Windex, and carefully and slowly bent, fitted, cut, and glued the front and outer side. Then I did the same on the other side.

When dry, I trimmed and sanded the sheeting, and test fit the fan unit again.

I'm satisfied with what I did, but I'm sure the method in the instructions will work too.

[Michael]

The instructions in Step 85 indicate the option that the exhaust sheeting can be done in 2 sections; the first from former F5 to F6, the second from F6 to F10.

I chose this option because the sheeting in this area sits below the plywood rails on the sides, so it's slightly different from the rest of the exhaust sheeting. I did it with one piece of balsa (probably easier with 2 halves), soaked with Windex. I carefully measured, cut, over and over, until I had a nice fit, and then glued from the bottom. The sheeting here covers the top edge of F5, but only half of the edge of F6, so that the later rear sheeting will have something to sit on. The sheet was cut a little long facing forward over F5, and I trimmed it after the glue had dried.

[Michael]

I sheeted the rest of the fan exhaust area my own way, deviated slightly from steps 85, 86 and 87.

I used a single 4"-wide sheet and soaked it with Windex. Then carefully curved it to fit, and started to cut, shape and measure. It almost completely covers everything, lacking a sliver on each side just behind F6. I cut and shaped the front edge to match the rear of the sheeting I already did, sitting half-way on F6. I glued everything from the bottom and the top sides. I added small slivers of scrap balsa to the sides near F6, and then I trimmed everything, except the overhang at the back; That'll be trimmed later.

Note, the exhaust area/curve sheeting becomes slightly shallower and narrower towards the back of the fuselage (at F10).

[Michael]

I glued the 3/32" thick strips (laser cut sheets approx. 1/2" wide) to the top sides of the fuselage behind F6. This was simple. The instructions state that the strips may be too wide and would be trimmed after. My strips were not wide enough, especially towards the rear of the fuselage, but there was ample material to fill in as needed. I then sanded the strips to match the inner curve and the outer fuselage sides.

It's not in the instructions at this time, but I trimmed and sanded the back (rear of F10).

[Michael]

Stabilizers/elevators sanded (surfaces and edges), and test-fitted following instructions as per step 89.

Cutting, sanding, trimming etc., for a nice smooth fit and a bit of a gap on the top for covering material; a larger gap on the bottom will not affect the structure.

There is no need to trim the hardwood spars to much, as the formers F8 and F9 will only allow the stabilizers into the fuselage a small amount.

I marked each piece as L (left) and R (right).

I did not glue at this time, as previously mentioned, to make covering easier. Because the stabilizers need to be glued from the bottom, I will find a way to keep the bottom open (not fully sheeted later in step 95) until after the covered parts are glued together.

[davidk]

I am both shocked (my lack of talent) and very pleased that my fuselage halves fit together with very, very little adjustment.  One former corner needed sanding to fit around a 1/4" balsa piece, and the tabs of the F5 and F7 formers were too tight, so they got a little bit of sanding.

For the Stabilizers, it "looks" like they are way off... but they are not.  Just a bit of sanding, as instructed, allows the Stabilizers to slide into the fuselage... very easy process.