Monday, May 23, 2011

A few days of progress

This post contains several work sessions.  I tend to forget to post.

Forward fuselage with shortened nose section taped on.
The picture on the right shows the forward fuselage with the nose section re-attached with tape.  You can see how the 3/8" cross section that was removed under the cockpit causes the the nose to shift back.  The next step is to remove the cockpit roof and a portion of the superstructure behind it. You'll note that I do this with the fuselage taped together as I hack away.  Note the clear plastic cockpit roof and windscreen
section in the foreground of the picture. The roof of
the fuselage will be removed to allow this clear piece to be inserted.






Fuselage with cockpit roof removed.

Below is the fuselage with the cockpit roof removed. At this point, the model is pretty-well hacked up. The old tail is gone, the nose section is separated. A 3/8" cross-section of the fuselage has been removed from beneath the cockpit and the cockpit roof is removed. Everything is held together with tape.

The clear, vacuum-formed, cockpit is set in place.
The next task is to remove the fairings surrounding each cheek gun position.  Also, the fairing surrounding the astrodome on the roof of the nose section must be removed. I used a combination of Dremel tool, x-acto knife and file for this.






The astrodome fairing is removed.





The Koster conversion provides fillersfor the
astrodome hole and chin turret hole (more on that later).



The Koster kit comes with plugs to fill the astrodome hole and the hole form removing the chin turret. I was surprised that they fit so well. They predicted the shape of the hole left over after the astrodomectomy pretty well.






The Koster-provided astrodome hole filler in place.


Koster provides clear, vacuum-formed parts to fill
the cheek-gun hole.

















Cheek gun hole filler in place. Fits well.
The Koster kit provides clear, vacuum-formed filler parts to cover the gaping holes left from removing the faring surrounding the port and starboard cheek guns. I was surprised at how well they filled the hole. If you look closely, you'll see the smaller-sized window molded into the center of the part. This will need to be filled in with putty and panted.

The starboard cheek gun hole filled nicely as well with the supplied part.  Again, I was surprised at how well Koster anticipated the shape of the hole that would be left after removing the fairing.

The starboard cheek gun hole with filler in place.

The chin turret faring was ground off. Note
the Koster-supplied filler piece to the right.
Koster-supplied chin turret hole filler, shaped for install.






























Chin turret hole filler. Note the snug fit, right from the sheet.
Tail section removed from the vacuum sheet
for shaping and test-fitting























Vacuum-formed, tail section removed from sheet.






Model with new Koster tail section, cockpit roof,
and nose section taped into place.

Sunday, May 22, 2011

Oops.

Well, this isn't good. While cutting off the nose section, my measurements were slightly off and I ended up with a double cut. It's not the end of the world, but it will add extra filling work on a project that already has enough. At this point, the tail section and nose section are removed. I've also removed a 3/8" cross section under the cockpit to shorten the overall length of the aircraft. The next step is to test-fit the new tail sections and the fit of the shortened nose section.

First Cut

The picture on the right shows the first cut. Note the razor saw near the top of the photo. The masking tape was used to secure the fuselage halves and to mark cutting locations. The key here is to spend time measuring and cutting your masking tape.  You'll need to ensure a straight line all around the fuselage. A nice, new razor saw is your best friend.

Getting Started

Last chance to change my mind and just build
a B-17G like everybody else does.
On the left is a photo of the Monogram B-17G fuselage halves taped together and ready for chopping. The Koster conversion kit provides directions on where to cut with some measurements to go by. You need to mark a spot just aft of the trailing edge of the wing root to remove the tail. The Koster kit tells you to measure 1/2" from the last etched panel line past the radio room window.  I found that this would cut across the wing root fairing and, after checking measurements from scale drawings, chose to shift further aft about 1/4".

The Goal


The picture on the right gives you an idea of the goal of this project. I want to end up with a B-17D that looks similar to the B-17C taking off in the photo.  Since there were only minor differences in the two models, this photo is a good example.

If you compare the B-17C pictured here with the earlier post showing the Monogram/Revell B-17G kit, you'll see some key differences in the aircraft. The B-17 was changed radically once the war began. Pre-war notions of how bombers would operate were proved to be incorrect.  For example, aircraft needed to operate at a higher altitude.  The thin air required a larger tail surface, so Boeing had to radically redesign the tail section. A tail-gunner's position under the vertical stabilizer was included in the new design to help protect the ship from rear attacks.  You can see the revised tail that was used in E, F and G models in the B-17G photo in the previous post. This is what gave the B-17 the nickname "Big-Assed Bird".  Also, the simple gun positions planned for earlier B-17's were not adequate (one might argue that the gun positions on the later models never met the need either.). You'll note that the B-17 C pictured here has a "bathtub" gun position on its belly.  A gunner would lie down in here and defend the aircraft from attacks from below.  This was replaced in later aircraft with turrets (a Bendix remote controlled version in early E models, followed by the ball turret.).