16 January – 20 March 2016: Firewall forward 28-30

16 Jan

Hours today: 1.3 Hours FF: 45.8 Hours total: 782.4
Rivets today: 0 Rivets FF: 114 Rivets total: 15 540

Made up some more oil pipes.

17 Jan

Hours today: 2.6 Hours FF: 48.4 Hours total: 785.0
Rivets today: 0 Rivets FF: 114 Rivets total: 15 540

Fitted various pipes and installed the throttle cable. That worked until I discovered that it wasn’t long enough to reach the throttle control when the control was in its correct position. That’s mean solved in the meanwhile (in May 2017).

20 March

Hours today: 2.5 Hours FF: 50.9 Hours total: 787.5
Rivets today: 0 Rivets FF: 114 Rivets total: 15 540

Attached SP10, RDAC and rivnuts for the ECU onto panel behind instrument panel. Unfortunately, I later realised I had installed them on the wrong side of the panel! They go on the instrument side, not the side that faces the engine. I also installed the autopilot servo for the ailerons.

And then nothing happened for a long time over the winter...

10 January 2016: Firewall forward 27

Hours today: 1.2 Hours FF: 44.5 Hours total: 781.1
Rivets today: 0 Rivets FF: 114 Rivets total: 15 540

 

fuel pump (2)

Fuel pumps attached to firewall with jubilee clips, and power cables connected.

Today I worked mostly on the fuel pump. It sits on its own mounting plate, but needs to be re-attached, done here with Jubilee clips. I also added the power cables. The fuel pump installation is supplied complete and ready to go, another factor in favour of the 912is.

The Airplane Factory specify not to use the original Rotax stainless steel case, but to fit a “tunnel” over the pumps.The tunnel flanges mate with the rivnuts just visible in the photo above.

I first added thermal insulation to the tunnel:

fuel pump (1)

Insulation on fuel pump.

then fixed the cover in place over the fuel pumps:

fuel pump

Fuel pump cover in place.

The final product looks pretty good, and should prevent engine heat from getting to teh fuel in the pumps.

9 January 2016: Firewall forward 26

Hours today: 0.6 Hours FF: 43.3 Hours total: 779.9
Rivets today: 0 Rivets FF: 114 Rivets total: 15 540

So I need to find a way to make up the oil pipes. I found a few cool tools online:

The  Knuckle Saver  Video: here. This is a small hand tool and looks like it works well:

knuckle saver

Moving up the scale is the EZ_ON. It is driven by a pneumatic drill, and looks very cool:

Products_EZON

If you want to push on really big pipes, then a CC-FP10 is what you want:

CC_FP10_Fitting_Pusher_BU

Parker, the people who do the hoses, also do an assembly tool.

Screen Shot 2016-01-19 at 8.52.47 PM

The only problem with all these cool tools is availability. And saving some money won’t hurt either. So what did I learn?

  1. I need to hold the fitting,
  2. I need to hold the hose, and
  3. I need to bring the two together using some form of mechanical advantage.

I gave the issue way too much thought, and a couple of things came to me:

The CC-FP10 uses straps to hold the hose:

Holding a hose with straps

Holding a hose with straps

If it works for a hose that size, it should be no problem to use small straps on a small hose.

Next, I remembered that I have a small vice for a miniature milling machine that can probably hold a fitting securely. It can.

Finally, I figured out that a drilling vice could provide the mechanical advantage. Aardendorff had one for just R315, or about $20 and they’re just 20 minutes away. It has 150mm/6″ of travel. It’s rough and ready, but that is all I need for this job.

150mm / 6" drill press vice

150mm / 6″ drill press vice

So here’s the method:

The problem - it's difficult to push the hose onto the fitting.

The problem – it’s difficult to push the hose onto the fitting.

Hold fitting in vice.

So: hold fitting in miniature vice.

Put miniature vice into drill press vice

Put miniature vice into drill press vice

Strap hose to drill press vice

Strap hose to drill press vice.

This step is the most tricky. I found twice around to be more than enough, and wrapped over the top, as shown, the strap pulls the hose down rather than making it pop up. Don’t wrap too close to the fitting, because the strap compresses the hose and stops it from pushing on to the fitting.

One strapped, turn the vice handle to push the fitting into the hose and viola! If you’re lucky. If not, adjust straps and try again. I found two attempts were needed to get the full push, and pulling the straps nice and tight saves wasting vice screwing on tightening them.

Job done

Job done

I know not everyone will have a convenient miniature vice, but I hope this idea helps you think of a solution that works for you. Leave a comment if you have a better idea.

It took about 5 minutes to do each hose, but there are only 9 fittings, so it was quicker to mess around with this ad-hoc technique than spend the time making a better clamp for the hose. DON’T FORGET to put the hose clamps on before you make up the second end!

After a lot of research, a shopping trip, and some messing around, I then spent 35 minutes actually making a hose or two.

 

8 January 2016: Firewall forward 25

Hours today: 1.4 Hours FF: 42.7 Hours total: 779.3
Rivets today: 0 Rivets FF: 114 Rivets total: 15 540

Back the oil system. I cut the thermostat mount screws to a decent length, and mounted them with loctite into the propeller gearbox.

Closeup of thermostat mounts screwed into gearbox.

Closeup of thermostat mounts screwed into gearbox.

Then I fitted NPT to AN-8 adapters to three of the ports on the oil thermostat, and an NPT to barb fitting on the remaining port.

Pipe fittings to oil thermostat.

Pipe fittings to oil thermostat.

Finally, I thought I’d make up some hoses. This turned into a mission for Hercules. The tube is just under 12mm, the narrowest part of the “push on” fitting is slightly more, so there is a problem to start with, but then there are those enormous barbs, visible in the photo. I found it difficult to push the tube over the first barb, and didn’t get anywhere near the second barb. So I phoned the factory, thinking that I might have the wrong tube.

The factory said, just push it on. They did say it took a lot of strength, and that the strongest person at the factory had been employed specifically to push pipes on. They recommended oil or grease, and lots of muscle power.

By the end of the day, the job had defeated me, so I started looking for a suitable tool.

7 January 2016: Firewall forward 24

Hours today: 1.9 Hours FF: 41.3 Hours total: 777.9
Rivets today: 0 Rivets FF: 114 Rivets total: 15 540

I mentioned yesterday that the engine mounting bolts are the wrong way around. I also fitted them without locknuts. Time to fix all that, at least on three of the bolts (the fourth was damaged, so I need to replace it).

NOT A GOOD IDEA! It would have been much easier to a) install the bolts correctly to start with, or b) turn them round before installing the exhaust. I’m too keen sometimes. Anyway, I removed the muffler, installed and torqued the engine bolts, then refitted the muffler.

With the muffler in place, I could install the heater pipe:

Then I fitted the exhaust. It needed a bit of jiggling for everything to line up correctly, then copper-slip on the joints, link it all together and put the springs on. I still need to secure the springs, so photos to follow.

6 January 2016: Firewall forward 23

Hours today: 6.3 Hours FF: 49.4 Hours total: 776.0
Rivets today: 50 Rivets FF: 114 Rivets total: 15 540

I test fitted bits and pieces of the oil circuit. It isn’t apparent where the oil thermostat should go, but there is a bracket supplied, and two rubber mountings that fit nearly into two threaded holes on the back of the propeller gearbox on the engine.

Oil thermostat bracket with rubber mount outlined.

Oil thermostat bracket with rubber mount outlined.

One rubber mounting is visible in the red marked area. The other is behind it, but still has its inspection sticker on, so it appears white. The thread coming out of the mount is too long for the threaded hole, so I’ll have to trim it. With the thermostat in this position, it seems to allow for reasonable oil pipe runs.

The I got involved in something far more physical. The cabin heat comes from a jacket around the muffler:

Exhaust with shroud fitted.

Exhaust with shroud fitted.

Firstly, the shroud skin didn’t fit around the muffler. After a close look, the flanges on the exhaust were not square, but at an angle slightly larger than 90 degrees. So I too a hammer to them, and did some light panel beating to get them to 90 degrees, then the shroud just fitted. I’m so used to working with aluminium that stainless steel comes as a surprise: it is hard and tough, and takes some effort.

Next problem: no holes in the stainless steel flanges on the muffler. So I drilled two holes, then fitted clecos to secure both ends of the shroud, then drilled two more holes, until I had gone all the way round, clecoing as I went to make sure that the skin would fit. It is a bit tricky: the skin can move diagonally very easily. Also, there isn’t much spare on those flanges, so everything has to be drilled just right, or you end up with holes that don’t go through the flanges. But all ended well.

Final (?) problem: the bracket that goes onto the pipe, bottom right in the photo above. That was a bit of a mission to drill and rivet accurately, but it worked in the end.

Now it is time to mount the muffler. It is supported by a triangular bracket, that goes onto the engine mounting frame. The bracket is supported on the frame by a thick blue pipe and a pair of jubilee clips (at least that’s what I call them). I’ve just remembered that I think they are called hose clamps?

Note that in the above photo, the engine bolt is pointing the wrong way. That’ll be fixed tomorrow.

It is important to get the pipe onto the frame and triangular bracket mounted in the correct orientation BEFORE putting the exhaust on. The pipe needs to be cut along its length to fit on the frame.

Then secure the muffler to the triangular bracket using two large hose clamps. There was a lot of messing around with the exhaust pipes to get everything at roughly  the right angle, then the clamps were screwed tight.

As an aside, you can buy a very neat tool for the clamps: it has a socket on the end of a wire rope, with a handle on the other end. Being a socket, it doesn’t slip like a screwdriver, and the wire rope means the handle doesn’t have to be directly in line with the screw. I saw one on the wall at International Clamps. I didn’t buy it, but I have subsequently found it is easier to use a socket than a screwdriver for hose clamps.

Exhaust in place.

Exhaust in place.

I was not sure what to do with the other hole in the shroud. The kit comes with a bracket and another short piece of pipe, but where would the pipe run to? A look at some photos showed other Slings with left just like the above photo: the hole should allow enough air into the shroud to feed the cabin heat.

4 January 2016: Firewall forward 21

Hours today: 0.6 Hours FF: 42.1 Hours total: 768.7
Rivets today: 0 Rivets FF: 54 Rivets total: 15 480

It was a busy day today, but not much building got done. I had to take the engine crane back to the hire place, open again after Christmas. Luckily they had allowed me to keep the crane safe for them, rather than charging me for ten days’ use. Then I went to the factory with a camera, and found a 912 iS open, about to get its MPI. I took about 80 photos, all too detailed to be of general interest, but they’ve been very helpful since then.

Also, the mechanics seemed to think I was a bit ignorant because of all the things I didn’t know. Then one of them asked me if I had the maintenance manual (available here). I did not. When I looked at it, a lot of my problems went away. This shouldn’t be a problem for newer kit builders, but I received even my firewall forward kit quite a long time ago before this manual had reached maturity. If you’re building a Sling and don’t have the 2.2 version at least, go and get the latest from the website.

With the maintenance manual, the Rotax installation manual and the Rotax detailed part list, I had enough to go on for a while.

One of the things I learned at the factory is that they are now recommending fuel lines be 8mm in both directions. I will need to replace the 6mm fittings on the fuel tank selector with 8mm. I am also short of a number of fittings, like fuel line barbs, one oil fitting, and the bolts I have broken so I have left the factory with a long list.

I’ve also asked for a quote on instruments, electrics and the finishing kit. It feels good to have the end in sight.

I also took the chance to clean up the seat which have been getting dusting for a good number of months, and start spraying them white:

Seat being sprayed.

Seat being sprayed.

3 January 2016: Firewall forward 20

Hours today: 2.0 Hours FF: 41.5 Hours total: 768.1
Rivets today: 0 Rivets FF: 54 Rivets total: 15 480

It is the New Year! I had spent a relaxed couple of hours preparing the fuel selector:

Fuel selector

Fuel selector

All the ports on the fuel selector are supplied not screwed in, in case they need to be removed for fitting. In the case of the Sling, they don’t, so step #1 was to fit each one with four small screws, all loctited, then punch a witness mark on each screw. The each port required an NPT right angle adapter (brass in the photo) and a bayonet fitting (blue in the photo).

My manual directs an 8mm pipe for fuel to the engine, with a 6mm return (both inside diameters). The Rotax manual recommends 8mm both ways.

At this point I was getting pretty fed up with the factory documentation, because all I had was the firewall forward drawings, 12 pages with a great deal missing. I needed some expert advice, and preferably a lot of pictures of a working 912 iS Sling installation. Luckily, the factory opens tomorrow.

30 December 2015: Firewall forward 19

Hours today: 6.2 Hours FF: 39.5 Hours total: 766.1
Rivets today: 0 Rivets FF: 54 Rivets total: 15 480

I spent the day on the brake system. First I move the brake bleed nipple down the to the bottom the brake caliper:

It was a tricky job as there isn’t a lot of room for the spanner. I also put a fitting into the top of the caliper and connected the brake tube.

The brake pipe runs up the back of the undercarriage, then into the fuselage through a grommet in the hole left for it.

Brake pipe into fuselage

Brake pipe into fuselage

From there, both brake pipes go to a t-piece from where a single line goes up to the park brake valve. I got this bit wrong, kinked that pipe and failed to get everything to fit. So I’ll need to wait until I can get a new piece of pipe and try again.

The Sling has a valve that holds the pressure to the brakes, used for parking. The manual does stress that it shouldn’t be relied on for long-term parking!

Handbrake valve

Park brake valve

It looks easy to fit, but there’s a trick. NOTE: It isn’t symmetrical. In the picture above, one side is clearly longer than the other. Getting the valve together in the little angle brackets is finicky, but not impossible. But get the direction wrong and it won’t all fit nicely.

Master cylinder to handbrake.

Master cylinder to handbrake.

In the photo, the correct direction can be seen. The park brake valve is also shown connected to the brake master cylinder. From the other end of the master cylinder, a pipe goes to the reservoir on the firewall.

Brake reservoir

Brake reservoir

The day went well, but ended badly when I couldn’t bleed the brakes because of the kinked pipe and unfitted T-piece. Onto the snag list with it.