For non owners here’s Rotorways sketch of the heatshield components. It’s a fabricated aluminium box that fits around and over the exhaust pipes and collector to minimise heat convection to the upper engine bay area. We are supplied with a large off-cut of 25 thou aluminium from the Tail Boom Skin. The material is skinned on both sides with white plastic film, some of which I removed from some of the parts in the pictures.

I really didn’t think there was going to be much to report here. A few bent pieces of Aluminium with big holes in - how difficult could that be? In truth, it’s fairly straightforward to make and install something that simply ‘Does the job’. ‘Fraid I ain’t made that way so I set about devising a method of fabricating a neat, square, accurate assembly. In some ways the job is fairly similar to assembling the body panels - everything is in mid-air and there is no real datum to start from.

I’m fortunate to have a full compliment of sheet metal fabricating machines at my disposal including a 50 inch Guillotine and 48 inch Box & Pan Folder.

But this is our smaller, 30 inch Universal sheet metal machine which will, shear, fold and roll light gauge materials - Ideal for most jobs on the Exec. Made in China (of course) and costing less that £300 it’s a great value piece of kit and in my mind, well worth the investment

We also have a pair of very high quality ‘Gilbow’ hand snips, left and right hand cut. These aren’t the cheaper, serrated blade, Aviation snips commonly available (which are fine for most jobs), but heavy, sharp, strong and relatively expensive, professional tools. Invaluable.

The construction method outlined in the video and manual seemed a good place to start so I began by making some cardboard templates of the two top panels. I soon discovered that there were too many unknowns to make an accurate template at this stage so I gave it up after an hour or so.

I decided to approach the job logically, in stages. I first made the transverse panel that joins together the two rear radiator shroud sides. This is not actually part of the box but it helps get the GRP shroud sides square. The template folds lines were an eighth of an inch short on each side so I made the panel slightly longer, sized to pull the shroud sides vertical when Cleko’d in .

I then made and fitted the central upper transverse panel, again using Clekos to correct the natural splaying of the radiator shroud sides. There’s not much available in the way of a Datum to check the sides so I clamped it together, sat on the floor behind the ship, eyed it up and moved it around until it looked right. If it looks wrong - it probably is wrong.

The third panel I made was the front transverse panel, exactly from the template.

Here’s all three transverse panels, all parallel to each other and square to the GRP shroud.

I then made some side panels from fairly heavy Chocolate Box cardboard. But instead of cutting the top fold at 3/4 inch long as per the template, I extended the fold to 3 inches long and made rough cut-outs around the pipes. I taped the cardboard sides to the GRP shroud and to the forward aluminium panel. I supported the forward end of the sides from the tail boom bracing tubes with tape. And here you can find a datum.

I dropped a tape measure down behind the intake manifold casting tubes to the forward top corner of the shroud box and set an equal height from the square frame tubes on each side thus ensuring that the front side of the box was parallel with the central upper panel. The dimension on my ship was 27 1/8 inches.

I made some smaller cardboard templates accurately shaped with 1/8 inch clearance around the exhaust pipes and taped them to the cardboard sides.

And here it is. The aluminium forward panel and the two cardboard sides, profiled around the pipes. The next step was to duplicate the cardboard sides in aluminium.

This is the process I used for making the pipe cut-outs. First I located and drilled the hole centre with a step drill

I then used a 52 mm (2 inch) Q Max cutter to cut a neat clearance hole. Snip the sides. File the sharp corners.

And here’s a new side panel.

I made the two top panels without the pipe cut-outs and drilled and Cleko’d the lot together. Wow - a box!!

Here’s one of the two forward mounts made from 1/8 in Aluminium and fixed to the frame with P clips.

The (nearly) finished item, viewed from underneath. It’s still just Clekoed together and the white plastic covering is still on most of the aluminium (except the left hand panel). I’ve highlighted the outer edges of the top panels and the fixing holes. I could see no point in keeping the full width of the top panels so they’re cut to overlap the extended side panels by around an inch and a half. I doubt very much if I’ve really finished the trimming of the exhaust holes in these panels. When the belts are tightened and the engine moves forward I’ll probably have to elongate them and maybe make another, sliding panel to close any gaps on top.

FUEL TANK HEAT SHIELDS

I’d learned from other owners web sites that the recommended fixing method for the fuel tank heatshields is not really up to the job and that movement and vibration can break the fixings in a short time. One solution is to use a strip of 4130 as a stringer to reinforce and stabilise the aluminium shield.

One end is secured under a manifold bolt whilst the other  is fixed to a ‘P’ clip around the frame. Not an ideal fixing point because the engine can move relative to the frame, but the best available. I rolled the aluminium oval shield to shape and Clekoed it to the stringer

To further enhance the stability and strengthen the shield I used my bead-forming tool (normally used to form beads on the ends of tubing) to roll a bead around the edge of the shield.

It will eventually be riveted to the stringer.

UPDATE: I’ve begun to trim and final fit the rear lower body panels and I’ve found that there’s quite a lot to be trimmed from both the heatshield and fan shroud bottom edges. The idea seems to be that the trimmed edge of these panels sits inside and just clear of the lower body panels.

Determining how much to trim off is not easy so I nibbled at them with my air panel saw a few millimeteres at a time until the lower panels fitted in the correct place and I had a three or four mil gap between them and the shields.

Hindsight is a wonderful thing but I really should have made the heatshield at the same time as fitting the rear body panels. It’s two jobs that really should be done together. There’s a lot of material come off - I completely cut off the four lower nut plates at the corners and had to install four replacements higher up the sides.

Anyhow, it turned out OK in the end.

This is the dimension I ended up with here. Other ships will probably be a little different.

The Rear Transverse Panel. Don’t forget it’s acting as a mirror here. There are only two Clokos. The black strip is the clearance between the rear shiels panel and the bottom of the lower rear body panels

This pic shows an elongated hole cut in the top heatshield panels for access to the engine mounting bolts when belt adjustment is required.