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Max Holste Broussard 1/72 Scratch Built Masters & Models


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The new block was cut along the horizontal separation line and the lower piece glued to the main cabin section. The firewall brass template was then screwed to the front and this lower part sanded. This includes a slight taper inwards towards the firewall. The upper part of this block was rough cut for the windscreen angle.

 

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The windscreen section was then glued to the main cabin window section ready for shaping. In order to get the fuselage shape right ahead of the glazing, the cabin piece was attached up against the firewall for sanding. A spacer at the back kept it against the firewall and it was screwed through the brass templates from both ends.

 

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Once the windscreen was sanded, a small piece was cut for the section between the firewall and the start of the screen. This was cyanoed to the brass template to hold it still and it was then sanded to match the firewall.

 

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The horizontal break line between the upper and lower cabin area was then covered in Sellotape as a glue barrier, the spacer and main cabin fitted together and a little thin cyano run into the joint to glue them together. This now just needs a little filling and sanding for the fairing that blends the fuselage into the screen.

 

broussard037.jpg

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Can you tell what it is yet? I'm pretty pleased with the progress so far. It's not been particularly difficult so far, just tricky working with quite small parts and sub-millimetre tolerances. The cabin roof will need sanding for the centre wing section. I'll probably make the centre section as a seeparate part, rather than it being part of the cabin casting. So that and the tail cone next and that will be the basic fuselage structure done!

 

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  • 2 weeks later...

No progress over the past week. I've been busy finishing some other projects for an "RAF 100" event at the local aircraft museum. I also spent a day removing and rebuilding my Jeep starter motor - a job more fiddly than scratch building in 1/700th scale!! I hope to get back to 'Bruce' shortly.

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  • 4 weeks later...

I had a very busy Easter holiday period, and none of it to do with modelling! However, my daughter was back at school today after two and a bit weeks off, so I finally had time to get back to the Broussard.

 

The cockpit roof forms part of the centre wing section. While I'll probably be moulding the centre wing separately to the clear cockpit part, I still need to shape the top of the cabin to fit the wing - and that required - the wing!

 

I found a block of resin which happened to be a little bigger than the wing chord and span and easily thick enough for both wings. After wet sanding what would be the leading edge on a flat bench, I ran it through the bandsaw, just slightly over size for the wing chord. This rough cut side was then also wet sanded, carefully measuring as I went, until the trailing edge was free from blade cuts and was the correct chord.  

 

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The bottom of the block was then wet sanded flat on the bench again, and the block run through the bandsaw once more, this time set to a bit over the depth of wing. The cut side of this this blank was then wet sanded giving a nice neat slab to work on. Next, the cut side of the remainder of the block was wet sanded so that too could be cut to depth on the saw, and its second side sanded smooth.

 

I now had two thin blanks for the main wing panels. This process was repeated once more on the remainder of the original block, and that gave me a piece to use for the centre wing panel with a bit left over for the tailplane.

 

broussard041.jpg

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The left over piece for the tailplane was then reduced in thickness on the bandsaw again and the leading edge and rudder cutouts made. Neither the wing or tailplane have their aerofoil sections sanded yet. Even like this, it's looking quite Broussard like - which is a positive sign!!

 

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The components so far.

 

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A slightly out of focus picture of the tailplane, now sanded to section. That was the first job today, working up towards sanding the main wing aerofoil.

 

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I wasn't sure how thin to go on the trailing edge. I didn't want the master or the cast part to be too fragile, so I stopped sanding at 0.7mm thick. What do you guys think? Drop it down to 0.5mm?

 

broussard047.jpg

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The wings were next. I marked the main spar and a rear panel/rivet line as references for the sanding. I then added a line on the leading edge, at 1/3 of the chord height. This would be the leading edge centre line.

 

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The underside of the wing was first. The section is pretty much flat aft of the main spar, so I began with the curve up towards the leading edge. A chamfer was sanded first, using graphite from a pencil to see what was sanded and what wasn't. Once the chamfer was sanded on all three wing sections, I turned them over to start on the top. The leading edges weren't rounded at this stage.

 

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Forwards of the main spar was sanded down towards the leading edge centre line. The rear 1/3 of the chord, from the pencil line backwards, was sanded in a chamfer towards the trailing edge. Once that angle was sanded, further pencil lines were added where the red dotted lines are shown, and this area was then sanded.

 

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This created a multifaceted aerofoil which was then fairly easy to round off into a smooth curved aerofoil. That was done on some wet and dry paper on a flat worktop.

 

broussard051.jpg

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Here's the wing section heading towards completion of the curved upper surface.

 

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When I was happy with the wing section, I started shaping the wing tips. These have a slight undercamber in the rear 1/3 of the chord. It's subtle at this scale, but still noticable.

 

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I also did some work on the fuselage. The two parts of the cabin were glued together, and then they were bolted to the rear and lower fuselage with a plastic bag trapped between the upper and lower parts. This allowed a little thin cyano to be wicked into the rear and lower fuselage joint. The upper and lower parts then had their joints sanded and then separated.

 

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Three small blocks were then glued together to form the rear fuselage under the tailplane area. The joints between these blocks formed centre lines which were aligned with those on the main fuselage. They were carefully clamped and thin cyano run into the joint to attach the tail piece.

 

broussard055.jpg

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Once the tail block was secure, I began cutting it down, first with the bandsaw to get the excess off, then with 80 grit sand paper. At present, the block has been cut to the correct length, but it hasn't been fully sanded to blend in with the rest of the fuselage. Once that is done, the next stage will be cutting the wing and tail seats.

 

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After the tail was sanded to shape, I began to sand out the tailplane seat. It would be impossible to sand by eye and get a good fit, but I had a plan. Instead a trying for a good fit, I sanded the seat a bit deeper than needed.

 

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I also needed to create a little fuselage just ahead of the tail. The fairing on top of the tail will be added later.

 

broussard059.jpg

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Out came the P38 car body filler next, and a small amount was mixed up and pasted onto the tailplane seat. The tailplane was then pressed down onto the fuselage, squeezing out the excess filler, being careful to make sure it was aligned side to side. The jig took care of the other alignments.

 

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A short coffee break gave the filler enough time to cure to the 'green' stage and I was then able to lift the fuselage from the jig. I left the tailplane attached for a while longer for the filler to fully harden. The excess filler would be trimmed off later. The fuselage tailcone also needed a bit of filler to blend it with the rest of the fuselage.

 

broussard063.jpg

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While the tail filler was curing, I began to sand out the main wing seat, starting with a thin slice through the bandsaw, followed by hand sanding.

 

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The tailplane was finally popped off, leaving a nice smooth, perfectly aligned seat on the fuselage master.

 

broussard065.jpg

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The fuselage was returned to the jig, along with the tailplane, this time with the cockpit fitted. More P38 filler was mixed and applied to the main wing seat. The main wing panel was pressed into place on the filler. It was checked from above that it was square to the centre line, and checked from the front that is was parallel to a steel rule resting on the top of the tailplane.

 

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A little while later, the wing was popped off the cabin. The main wing had been used to make the seat as it's longer span was more accurate to align squarely. When the centre wing panel was fitted to the cabin top, it was a perfect fit on the filler. I guess my wing section sanding was pretty accurate!

 

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The excess filler at the top of the screen and around the sides was wet sanded a little while later, and the aircraft components placed together for a photo. Now it's really starting to looking like a Broussard.

 

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The last job of the day was the fin/rudder assembly. I decided I only needed to make one pattern which would be used for both sides. Two pieces of thin modelboard were glued together into a thin sheet. The glue joint gave the piece a centre line to work to.

 

This was wet sanded on both sides until the desired thickness was reached. The outline on the drawing was extended and the modelboard placed over the drawing to mark out its size. The taper was marked and cut first, then the height cut before sanding the radii on the top and bottom of the fin. 

 

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Once the basic shape was sanded, the rudder taper was sanded along with the leading edge curve. The top and bottom of the fin and rudder were the last to be rounded off as seen from the front.

 

broussard073.jpg

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A high pressure over Europe has brought Mediterranean weather to the UK for a few days. With a Summer like day in mid April, I decided I'd go out and catch some Sun this morning - not sun bathing, but photon catching in Hydrogen Alpha wavelengths of light!!! While the Sun is deep into the low period of its 11 year activity cycle, there was still some interesting prominence activity, with the lower right one being about three times taller than the Earth's diameter!

 

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By the time I finished and packed up, it was time for a quick lunch, before heading to the building bench. I decided to tackle the odd shaped cowl next. It starts our round at the front, and transitions to a rectangular section with rounded corners like the front of the fuselage. I began by turning a rough blank out of model board.

 

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The centre was drilled out and the outside, turned down with a combination of the lathe tool and freehand work with a scalpel and sanding block. A styrene template was periodically offered up to the resin cowl to check on the profile. It took a while, reducing the shape by fractions of a millimetre at a time.

 

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The front section of cowl was cut away, and sanded to the desired depth. The rear part of the resin, that was in the lathe jaws, was also trimmed, and the brass template from the front fuselage attached with cyano to the back face.

 

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The front piece was then carefully lined up and glued back on.

 

broussard077.jpg

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The rear part of the cowl was then sanded to the brass template and then some P38 filler carefully applied to allow the front and rear to be blended. This will probably take two or three applications to sand and fill any low spots. It's going to require some careful sanding.

 

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I couldn't proceed until the filler cured, and as it was close to school chucking out time, I packed up and went to collect my daughter, but not before another feel good picture. I was very happy with the way it was looking.

 

broussard079.jpg

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Friday afternoon was spent filling and sanding the cowl.

 

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The postman also brought the Broussard decals that JamesP ( from Britmodeller ) kindly sent me. While these decals won't be used on the first two models of the Breighton based Broussard, they are a useful reference source for the size of some of the smaller markings and stencils. This should help with the graphics for my own decals.

 

broussard081.jpg

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