HM14/360 canopy

Picture-reports of constructions/parts.

A view of how my canopy originally was. A bended 3mm lexan for the front. A alu structure with covering of plexi of 1 mm. The turtleback has a single alu tube in the front and the rest is plywood plate with a plexi. It was a good canopy, but ... rather small for me.

I made the terrible error to remove my front lexan. I couldn't get it back like it was originally installed. So ... I decided to make a new one in my favorite material. Wood. I started to make a template. The two side plates hold the three internal plates on its place. plates are 12 mm. I had to check what room I had for this higher canopy. Luckily I did it. You will see the reason later. A word of advise ... don't do this control as rough as I did.

The front plate had some holes to make I didn't had to remove the two instruments which I already installed. You see the simple L-angles which hold the plates together. The black line refers to the top of the canopy on that place. I always cut my plates a bit longer. Made errors in the past. Cutting is easier than making longer.

After I made a rough curved plate between the back plate and the middle plate, I installed the plate between the middle plate and the front one. The next task is to draw the curved line which you will cut out. As you can see ... a task that not always is done in one go. Be sure that you have a nice curved line. No tight bends!

Moment of truth. I made a quick lamination of four layers of plywood of 2,5 mm, 10 mm wide. The next day I could remove the middle plate and lay that part on top of the other plates. I crawled (hindered by the front plate) into the cockpit. Word of advise ... make the front plate have the same lower line as that nearly vertical plate in the cockpit. Easier to get in. Check the place you have above your head. Remind ...a headphone still has to be on top of your head.

Ok, you have the top line. Now the side lines. I advise to first make the sides on ONE side. Place a paper and draw the curve and redraw it on the other side of the plate. If you don't do it ... it is VERY hard to get the sides symmetrical.

You see here a next mistake I made. I was placing the plates full with holes to place the clamps. Just count the holes. Euh ... I have 20 clamps. Understand the problem? So ... I decided to make the lamination two layers each time and staple the layers into the plates. You can also see that I made a line at the side. It is just a stick of 5 x 10 mm. I made small holes in the plates to glue it on its place. Give it some bending. The layers are easily clamped with paper-clamps on several places.

The result when I made the layers loose. SPRINGBACK! 2 cm (nearly a inch). I had to change my idea about the amount of layers. I now planned to see if the springback would disappear or decrease if I placed the third layer (the third layer was now intended as the final layer and was 20 mm wide, except on the sides. There it was 15 mm). The next day I saw the result. Still springback.

Problems need to be solved. I placed a fourth layer ON THE INSIDE. I removed the layers from the template and clamped them so the sides were 2 cm closer to each other than on the template.

The next day I could test the fitting. GOOD! Here you can already see that I made a structure in the right side. There I will place the hinge. The vertical line of the canopy runs further in the side. The left side will get a removable door. No hinges. The exhaust pipe passes too close.

The hinge is a simple stainless hinge I bought in the D.I.Y. (= Do It Yourself). I reinforced the places to avoid splitting of the wood. You can also see the gussets I used.

The removing left door will slide in guides. Here you can see that a two simple sticks of 10 x 10 mm become guides.

Here we were busy installing them at the front of the door. Note: I didn't place guides on the bottom. I feared they would be kicked a lot. During a meeting that same year I was proved to be right. Many people hit that spot with their feet. It would lead to broken guides for sure.

The door was made with sticks of 10 x 10 mm. At the center we use two sticks to create the same width like the vertical line in the canopy. All was glued on the place where it should be. I use paper to prevent the door being glued to the guides. I missed 1 cm with paper. It nearly became a problem. The person you see is a volunteer of my school named Stefan Cramers.

The resulting door. It still need to receive the full guides. But the system already works with these gussets glued.

A problem we (Stefan and I) didn't think about. The guides at the front make a step. But ... it is a negative step. If we fill this area with straight angles, the door will be stuck. Solution: we need to glue a part with a angle that is the same as the angle the door is moved along the rear guides. To fill the hole completely I need to place a small fixed triangle.

We test the lines. It looks like there is no problem. But ... there is. Do you see it? Solution totally below marked with a *.

This would probably be the situation if Henri Mignet would sit in the fuselage. Stefan can still wear a punk haircut (cock's comb).

I am glad I can finally sit upright and still be able to wear a headphone. Note: don't make the top line too sharp at the front. You need to be able to move your head forwards too, I guess. This seems to be a good top line. View around was good. Even with that side line now blocking my view to the camera.

The front part. I no longer intend to use a simple curved lexan plate. I wanted to make a wooden structure like the rotating canopy. I used the front plate of the first template as a template to make this plate and I fixed it with clamps to the cockpit.

I made a second plate which presented the bottom line. I bolted the part together using those two central plates (left overs). I drew the places where the lines ended of the rotating canopy and I first tested roughly the ideal place for the beginning of the lines. Once sure I made the holes and inserted the 5 x 10 mm sticks. They are not glued yet! Note the angled edges. Use eye sight as guide to make them. Look over the top plate and see if the angle on the lower plate fits that eye line.

Our first idea was to construct the first part on the fuselage. But we didn't keep that idea. Anyway, we needed to disassemble the template to place it on the fuselage. It was needed to control the lines. All seemed OK.

As you can see in the picture above. There are some struts and engine-mount tubes running through the place where the lexan should be. I wanted to solve that problem with making two extra lines to later place a tailor-cut plywood over it that will fit perfectly around those tubes. I will use rubber to make the final seals. Here Stefan uses a cardboard to test the ideal shape. A 0,75 mm plexi is placed as lexan-replacer.

Once the shape of the part is know, I cut out the wooden template part and fix it. Same things is done for the next extra line.

Here you see (in a later phase) why those lines are needed. Onto those lines I will glue a part that will wrap around the engine-mount tubes. But ... I did forget a third line! One was still needed just above the tube of the strut that holds the front wing. Ah, I will place that one later.

Don't forget to use paper between template and layers! Here you can see it is tough work to place those layers on those angled sides. Keep in mind, you need to avoid that layer part need to cross over each other to hold each other on its place. On the most angled parts I uses a large border to be sure I didn't place too short. Later I will use the Power-file to make the shape right. The first two layers are a pain in the a**. They move all the time while you try to fix them. Once those are there, the next layers are easy.

OEPS. I didn't do what I tell to others. I did forget the paper on some places. I was able to get it loose. I was lucky. A bit more and I had to destroy the part o save the template to make a new one.

A proud builder. Stefan, many thanks for your help

And it fits! I truely like the way the lines run.

Before I was able to see it it did fit, I had to place the bottom flat. Remember I used a large border. Well, here you see me using a Power-file to get the bottom flat.

Also I needed to make reinforcements to place the bolts. I simply places five layers of plywood and shaped them later.

I told you in the beginning to check carefully the shape of your design. I was lucky. There still is 1,5 cm space between wing and canopy when I pull the stick towards me. I thank my guardian angel again.

Here I am preparing me for the next step. Making the turtleback. I first intended to use the same system as the original. But ... I didn't succeed into copying it. I plan to make a structure again and cover it with fabric. Here I check the top line. When I later place the BRS behind my seat, the chute will be able to tear itself through the fabric.

I skipped this part. I am still tinkering on that idea. I intend to use 0,75 mm plexi on the sides. Due to the fact that I have curves in three dimensions, it is hard to make the sides in a single plate. Each side has two plates. I wanted to cover the edge with a extra layer of plywood and staple it all to the structure. But ... I cannot use metal staples (rust) and I fear that plastic staples will not stand the elements (hot and cold weather). I now plan to screw the plexis or ... use superglue like some Flying Flea builder did before.

Solution *: the vertical lines are not symmetrical. I was not correct in the placing of the middle template-plate. The left line is 1 cm further backwards than the right one. I am sure nobody will see it, if they don't know it.