Old School Model Works: Raven ducted fan jet

[Michael]

A few TEMAC members are building a balsa  construction jet featuring a 64mm ducted fan, low wing and V-tail design, and fixed (non-retracting) landing gear. Wingspan is 47¼ inches.

https://oldschoolmodels.com/raven.htm

I received mine today, and am getting ready to start building.

The kit includes some hardware, packages of sheets of laser-cut balsa and plywood, plain (uncut) balsa sheets, balsa sticks, rolled plans, instructions, and some decals.

A few corrections have been made to the instructions since they were printed, so I printed out a sheet with those corrections. The corrections are listed below:

On step 82, P3 should be the piece glued into the fuselage - where the EDF cover will evenutally mount to.
 
When building the EDF cover (step 106), P2 should be used, as it has the notches to hold the semi-circles.

Former F4
One more mistake that was pointed out to me this morning - regarding F4. F4 is a balsa former that goes in place just in front of the EDF.
The outer tabs on F4 are not in the right place - if attached to the fuselage as-is, it will make F4 too high and block the lower portion of the fan - robbing power.
So, trim off the tabs on F4 before attaching it - it glues into the same place as shown on the plans, and at the same height. That way won't block the fan.

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The instructions feature many construction photos, so I won't post similar shots, but I will post images of my progress and add comments.

[Michael]

Half-elevator construction took about 15 minutes, of slow and careful, but easy work.

Just follow the instructions. I used medium CA glue.

[Michael]

I've been flying electric ducted fan jets for over 20 years, but this will be my first ever self-built balsa EDF model.

[Michael]

Second elevator panel took about half the time.

[Michael]

Funny. I was working on a small jet as a test to build a larger version later.

Very similar!

[Michael]

Wing construction started. Instead of gluing down the bottom spar, I pinned it in position. I removed the ribs from the sheets and trimmed/sanded them. I'm using the triangle-jig (included in the kit) to make sure the ribs are glued on perpendicular to the building surface.

So far, I find the laser-cutting and parts fit to be excellent.

The small black-and-white images in the instructions are a little challenging to use as references, but the larger colour images on the OSMW website really help a lot!

https://oldschoolmodels.com/mpics/raven/

I'm keeping my ipad close to my workbench, but not too close, to prevent accidental contact with glue.

[Michael]

Taking my time. Ribs 3 through 9 glued on the hardwood spar. The larger inner ribs are glued on later.

[davidk]

I'm following steps behind Michael, double checking everything I do.  Since this is my first build I'm trying to follow instructions exactly and slowly.  The 2 tail sections are done, straight, and flat... so that's good.  The instructions are very good.  I used medium CA for the supporting structure, but I used wood glue for the sheeting.  I couldn't see how to get the glue down and then getting the sheeting on exactly without the CA setting off too quickly.  The wood glue gave me a bit of time to adjust.  I'm not going to post everything I do... it'll just be duplicates.  I just wanted to show a start, since this is my first.  It's fun with such an exactly cut kit.

[Andy Hoffer]

Looking forward to David's observations on 3D printer builds vs balsa and ply builds.

Don't forget to savour the rich aroma of balsa and plywood!

Andy 

[davidk]

Starboard wing ready for sheeting.

[Michael]

Wings ready for sheeting. Maybe tomorrow, or the weekend.

A Master Airscrew small razor plane made easy work (done carefully) of shaping the trailing edge doublers (step 22).

Builders must be sure to follow each step in the instructions. I overlooked one step (step 23), and neglected to cut out the center of rib 2 before gluing on the upper hardwood spar. Luckily, I was able to carefully cut it out later, through the slot for the dihedral brace.

[bfeist]

I like this, two build threads in one!

[Michael]

Sheeting the upper wing; I'm deviating slightly from the instructions.

The instructions ask for the top sheeting to be softened with Windex and curved to shape, before being glued to the wing.

I've taped the sheeting sections together with masking tape, and used wood glue in the seems. I wiped off excess. When dry, I'll add some CA glue to the inside seams as a stronger bond.

Some of the balsa sheets are lighter and more bendable than others, and I'm using them for the front of the wings, where the curve is more prominent. I'll glue the full assembled sheet to the leading edge, and then carefully bend it back the ribs and to the trailing edge. If needed, I'll soften the forward part of the sheeting as I progress.

[davidk]

Were the edges of the balsa sheets straight enough to glue together without sanding them first?

Looks like you put together 3 pieces... the 3rd piece is that little triangle corner?

[Michael]

Yes, yes.