Saturday 3
Well now that the project is back down in the workshop, things aren’t quite as roomy as in my 3 car garage, but it sure is warmer. The more I look at this thing, the more I can see that it requires filling. Some gel coat had peeled back around the filler hole area so I had a try at building this up with some filler to get it even looking. I generally touched up a few other spots while I had some sticky goop all mixed up, but I can see that I still have quite a bit of work ahead of me.
Sunday 4
Now that the fuselage is out of its cradle I will need a good way of supporting it. I have some dummy spars I have made out of cedar but they are not the correct thickness, or very strong so I decided to make some new ones. I was going to make them out of plywood but I couldn’t find any material thick enough so I went with laminating some oak. All in all they turned out to be very sturdy, but quite expensive.
The sun was still shining outside, and me being weak I called it quits for the day and went flying for a while.
Monday 5
I wanted to fit up the tail wheel spring and the only thing that needed to be done was to Redux it into the stern post. With all of my try/ retry cycles I wasn’t really happy with the gap so I decided to machine up a spacer to make it a tighter fit before I bonded it in place.
Tuesday 6
Before I actually bonded the spring in for good I wanted to make sure I had the alignment spot on. I drew a line the length of the workshop and then put the centerline of the fuselage over it. (Easier said than done). This gave me an alignment mark to make sure the tail wheel spring was in line with the fuselage center line. The last step was the easy part, mix up some Redux and bond it into place.
Wednesday 7
I am using Graham Singleton’s tail wheel mod, so my tail wheel assembly doesn’t need the horns. I hack-sawed these off and gave all of the bits of hardware a coat of paint.
Thursday 8
I did a trial fit of the tail wheel and it seems to work quite nicely. With 30 degrees of rudder deflection the wheel turns 80 degrees, so it seems that the aircraft should have a nice tight turning circle.
Saturday 10
I sanded back last weeks filling and added more in the low spots and pin holes. I think that this sanding and filling is really going to torment me, always being one coat away from perfection.
Sunday 11 ~ Friday 30
I was getting a little discouraged by the slow progress on my project so I decided to take two weeks off work and work on the project. My friend Graham Singleton agreed to come over and stay for a couple of weeks and work with me. I had a couple of goals, which were to make the firewall, fit the doors and try to fill at least one flying surface.
The Firewall.
Well the book starts off by telling you to make some templates out of cardboard which is really good advice. I had some pretty stiff card that I was able to make up and bend to fit. Sure enough, quite a bit of fitting and fiddling around was required. The approach I took was to make a part and then make up the next card board template to suit. The only change I made was to make my own clips instead of the P clips. The reason being that the rubber on the clips prevented a nice flush fit up to the the frame. I found cutting the stainless steel quite tricky. I tried my tin snips and even after sharpening them, the material tended to fold in the jaws instead of cutting. I purchased some new cutters and even those required the jaw pivot to be quite tight before they would reliably cut.
I made a couple of small departures from the plans. I used home made clips to fix the firewall to the engine mounting frame rather than the “P” clips provided. The “P” clips tended to hold the fire wall away from the frame quite a bit and I couldn’t get it to sit down snuggly. I also made a couple of tucks in the metal at the top to close it off around the corners. I found the clearance between the rudder cables and the holes to be pretty tight so I intend to fit flexible nylon grommet material around the holes to protect from chaffing. The hole on the starboard side ended up being quite a bit larger than the plans in order to get reliable clearance.
By the time I had made the template, and cut, bent and fitted the 3 pieces, I had invested the best part of 25 hours. My only concern is that it is not really a true firewall in the strict sense of the word because there are a number of small holes.
Fitting the Doors
Well there is nothing special to say here, just take your time. They actually don’t fit all that great so I wouldn’t suggest you try too hard. Graham’s recommendation was to get it as close as possible and then fill the gaps. Although I haven’t tried it yet, the suggestion was to put on about 3 layers of DUCT tape onto the door frame and put in filler around the door sill. The idea is to then close the door and the DUCT tape will act as both a spacer and a release agent.
There has been a bit of discussion on the net about using a heavier type of hinge, I wasn’t able to come up with something I liked, but I must admit the hinge supplied didn’t look very sturdy.
Another suggestion on the net was to reverse the mounting of the gas struts. Apparently some folks believe that it reduces the problem of the door-frame being raised proud of the fuselage over time. I don’t know if I am missing something here but I could understand how this might help. I intend to leave it closed up under tension with a little local heat (to simulate a hot day) and then fill the fuselage match.
I made a simple change to the way the locking pins are attached to the rod ends. Europa call for a long slot to be cut into the 10 mm rod. I started doing this and it was quite apparent that this didn’t leave much material to support the pin, especially when a hole is drilled in it. I decided to make some fork ends out of some aluminum plate. I simply cut some flats on the push rods and riveted on some cheek plates. The edges have to be chamfered to ensure that it will pass through the bush on the doorframe. Apart from being stronger I think it was quicker to manufacture.
The Third Pin
A couple of people have made a center locking pin for the door, and there has been quite a bit of discussion on the Europa forum about this. The door has a couple of problems that an additional locking pin will address. The first thing I noticed was that once the doors were fitted, it bowed at the middle. Apparently the problem becomes worse when the air vent is opened and the cabin is slightly pressurized, and in some cases the door bows out enough to suck your shirtsleeve out. The second issue is that it is possible to engage the front pin and not the rear pin and the door appears closed, that is, until you reach 100 knots and then it blows off.
The third pin that I made was designed by Cliff Shaw and fitted to Bob Jacobson's Europa. Cliff also made one for Tony Krzyzewski, but unfortunately Cliff could not get his PC to give up the drawings. He did have a photo so I decided to work from that. As you can see from the photographs there are 10 parts needing to be manufactured:
1.
A pair of triangular cheeks
2. Locking pin
3. Square bush for the locking pin
4. Pin receptacle for the fuselage
5. Locking pin bush for the doorframe (not shown)
6. Spacer for the cheek plates
7. Pivot tube, fits over the AN525 R16 bolt and through the spacer.
8. Push rod to attach to the shoot bolt rods.
9. Bush / spacer for the push rod.
10 Backing plate
I made two changes to the design. Cliff Shaw's pin seemed to be 12.7 mm, which didn't leave much material in the doorframe so I reduced my locking pin to 10 mm. I also made a square bush for the pin to fit into. This gave a much smoother sliding action within the cheek plates.
The geometry of the cheek plate pivot point give a 12 mm movement of the pin from open to close. I machined a matching bush to go into the doorframe, but I made it a “blind” bush. This is to prevent the chance of rain getting under the doorframe and running inside. I will need to make up something to stop water from entering via the other door locking pins.
The finished job worked really well, the locking action is quite firm and it is pretty well impossible to close the door with the front pin only locked in place.
The down side is that this represents about 40 hours of effort and some of the parts are difficult to manufacture without a lathe. I don’t own a milling machine, but it would have been very useful for fabricating the push rod (item 8)
The drawings below are outlines of the push rod and the cheek plates.
(Items 1 & 8) The two dimensions are in millimeters and if you want
to copy it, all you need to do is to scale it and print it out as a pattern. They
are made out of 16-gauge mild steel, and the slots are 9/64th.
The pin and square bush are fabricated as two parts (Item 2 & 3).
I originally tried making it out of square material, with one end
machined down to 3/8th but I found that it was nearly impossible to
assemble this in the door frame, so I ended up making the pin separate and
boring out the square bush to suit. To locate it in place I drilled and tapped
it and used a socket head screw. This
proved to be very handy when trimming up the length of the pin and adjusting
the amount of chamfer it needed to lead into the bush correctly.
The backing plate (Item 10) is made out of 16 gauge material and the pivot is a AN525 R12 bolt. The head of the bolt was filed almost flat and it was then silver soldered in place. You will note from the photo that holes are drilled to allow the Redux to bond better. I’d suggest that a similar layout is followed, otherwise the Redux squeezes through and the cheek plates will not pivot. The dimensions of the backing plate are 35mm by 70mm and the pivot hole is 22mm from the top and 21mm from the side
Bonding in the windows
This is a pretty “worry-some” operation. Allow your self a good 3 hours and don’t attempt it on your own. It was interesting because one of the acrylic windows fitted in the frame with almost no sanding and the other required quite a bit of filing and fitting. You will need about 90 grams of Redux for this operation. I used 4 nylon straps, but I’d advise using 6. You will also need to make up some foam wedges ahead of time. Once I got it all tensioned down I then used the foam wedges to apply more tension in areas where I needed it. I had a couple of spots that just would not sit in place and I had to put in some sheet metal screws to pull it down.
The port window was quite a contrast. It just seemed to sit in place and the four straps pulled it down just fine. The only tip I can offer it to remove the masking tape on the inside of the windows as soon as the Redux is semi cured. I left it too long and it was really difficult to clean up, I spent a whole afternoon on just one window.
Filling a flying surface.
I must admit I have been putting this off for a long time. There are many opinions on the Europa news group but I tried using the “fishing line method” . For filling material I am using the Expand Cell that came with the kit mixed with Carb O Sil in a four to one ratio. For epoxy I am using the West System Resin. Mixing this stuff up in a repeatable consistency is a bit tricky, but the idea is to end up with a fairly dry mix. The West System comes with pumps, so for my mix I use one pump of resin, and I put in two scoops of Expand Cell / Carb O Sill mix. The scoops I use are stolen from the kitchen and are 1/3 cup measures.
The general idea is to mix this stuff up and then spread it out thinly on the surface and work it a bit to remove as many of the bubbles as possible. To spread it evenly, I lay over some 40 thou nylon cord with weights on each end and put it on with a 150 mm trowel used for dry walling.
To do one surface you can plan on spending 3 to 4 hours from when you start the preparation of the surface until you're finished. To prepare the surface I scuff sanded it with Scotch Brite pads, and just prior to applying the filler I put on a very thin smear of epoxy resin to help the filler bond to the surface.
