Week 147 - Fuel System cont. 5

Hours to date: 1307.5

A quick update.

I had a much better second attempt with the fuel probe, after buying a proper pipe bending tool (which is pretty cheap at under £10). It made the job so much easier.

A slight complication as the metal plate on the back now fouls with the O-ring sealing ridge on the tank. Will have to consult Pete to see how he solved this problem.

I cleaned out all my fuel hoses too. Some with the safety wire and cloth dipped in Acetone technique. The others, with the quick release fittings do not allow this technique so I just poured fuel through them (from one Jerry can to another).

Of course if you are smarter than me you would have done all this before putting the hose fittings on :)

I finally got the hose guides fitted and am happy to report that they work really well.

The fine filter is now mounted and I've only got a few more composite screws to do and things will be pretty much done on the fuse regarding the fuel system.

I've swapped over the wings and will now bring the Port wing up to speed with the same jobs - so I most likely won't do a post for 2 weeks or so while that happens.

Cloth (dipped in Acetone) on safety wire technique for cleaning hoses.

Pipe bending tool - just trying it out here on the wrecked fuel probe.

2nd attempt at fuel probe - much better result!

Fuel probe end - inner copper wire must be separated from ali tube. Done with plastic 'squares' supplied.

Hose guide mounts in place - ready for their P-clips and flared tubes.

With P-clips and flared tubes in place - works well.

Port side

Fuel system overview

Fuel flow senders getting sorted with mounts.

Swapped the wings over.

Week 146 - Fuel System cont. 4

Hours to date: 1294.75

Good news is that one wing is pretty much done regarding the fuel system.

Bad news is that I totally screwed up the fuel sender probe job - so it looks like I'll have to order a new one of those. The tube did not bend very easily at all and I ended up cracking the pipe open :(

I bonded in the fuel vent line - a fairly easy job - although you are working blind as it's inside the tank. I put a machine screw in the tube end (after wrapping it in duct tape and covering it with release wax) to stop any flock going in there. The manual warns against this so I was a bit paranoid about that happening.

The thread sealant and metal braided hose arrived so I was able to complete the fuel flow transducer installation for both lines.

I also put thread sealant on the fuel pressure sender - which is screwed into the end of the banjo bolt on the fine fuel filter. 

I've also figured out that I can put a wing on by myself. This is a great help as I was able to do the return line bulkhead fitting into the tank and also make up the hose for the feed line.

Finally the composite screws have arrived too so I've installed the fine filter mount at long last. 

I made up some composite screws to the correct length for the flared tube mounts too. I just bought some machine screws and cut them to the right length then screwed them into these special composite screw mounts that have a threaded flange at the base. I used Loctite retaining fluid to secure them in place. Bonding those on the spar tunnel will be the next job I think.

It may be a boring couple of weeks after that as I will most likely do all the jobs that I've done on the starboard wing to the port wing.

Flop tube easily clears vent line.

Coat hanger wire mock up of fuel probe bends

Vent line end with screw in end to stop flock going in

New toy! Right angle attachment for the mighty Dremel

Thread sealant - this stuff is the business

Bit of a mess of hoses here until I get them sorted with composite screw mounts

Both fuel flow senders in place with hoses

New route for the oil cooler hoses - to the left

This is as far as I could get the wing on by myself

Getting me wing on!

Fuel feed line complete now with braided hose to tank

Return line bulkhead fitting now bonded in

Composite screws made up for the spar tunnel (hose guide flared tube mounts)

Bonding in the fine filter mount composite screws

Ditto

Week 145 - Fuel System cont. 3

Hours to date: 1285.25

Well this fuel system seems to be taking longer than I thought. I don't mind spending lots of time on it though as it has to be right.

I bought some fuel flow transducers (£170 each!) as I really do want to know the fuel flow rate. Two are required as the UL power is fuel injected so has a feed line and a return line. The system pumps through a lot more fuel than is actually used by the engine (up to 100 litres an hour) so the Dynon uses the data from both transducers to determine actual fuel usage.

I've already fitted the return line one as you'll see below.

The feed one is not fitted yet as I'm still waiting on my steel braided hose to arrive.

Before I fit the adapters to the transducers finally I will apply some thread sealant. I've just ordered this so will get that done next weekend.

Below you will see my solution for guiding the hoses close to their exit point in the fuselage to wing root.

The flared tube is made of anodised aluminium and weights nothing - also it is the perfect surface for the nylon hose to smoothly run through with no wear (not that the hose will move much in there once the wings are on).

The flared tube is then held in place by a P-clip (which is attached to the spar tunnel via a composite screw - again this part is still to arrive).

The flared tube part in case you're wondering is actually called - wait for it - a Flesh Tunnel. What some people think is a good idea is putting these things in their ear lobes! Don't think I'll be doing that any time soon.

Little did the jewellery people selling me these tubes know that they would end up in an aircraft...

As you'll see below I tried to do both tubes/hoses with one composite screw - but this was too much of a compromise for both hoses need to be in just the right place - so I'll use two composite screws here.

I've applied some 'Cool-it' tape to the cell and fuse where the oil cooler will sit. I don't want the heat from that coming into the cockpit too much.

The new 'Cool-it' tubes arrived too so I was able to fit those to the oil cooler hoses and figure out where everything is going to go. After a bit of research it looks like I will be okay to get the fittings for these through the firewall after all, but I won't do any of this until the engine and other components on the firewall are in place.

Onto a real fiddle of a job. Bonding in the fuel overflow/vent line. Access is quite limited through the fuel tank access hole plus the flop tube is now in there and gets in the way a bit. Anyway I got the area roughed up and bonded it in with flock and one layer of glass. I built a special block of wood to hold the hose in place while it sets and wrapped the flop tube in a plastic bag so it didn't get any flock on it.

I'm going to bond in the other end - up by the fuel filler hole - next.

Finally, I'm now reading up on how to install the fuel probes that will go in each tank. I previously bought some pipe bending tools so that will come in handy - you only get one go at bending this tube so lots of thought has to be done beforehand.

More on that next week...

'Red cubes' fuel flow transducers

With adapters and fittings on.

Position of feed line transducer

'Flesh Tunnel' flared tube for guiding the hoses.

Return line transducer in place.

Front view - composite screws to mount the transducers still to come.

Hose guides - first attempt. Not successful using only one composite screw

Hose guide on other side. Getting position sorted.

'Cool-it' tape applied to oil cooler area

Oil Cooler with 'Cool-it' tube on the hoses.

Roughing up the area for the vent line bonding

Wood block I made for holding down the vent line while it bonds

Wood block doing it's job. 12" Spanner is for weighting it down while it sets

Fuel probe and bending tool.

Week 144 - Fuel System cont. 2

Hours to date: 1272.5

A bank holiday weekend for us in the UK so I got a bit done.

The parts arrived for the Fine Filter - so I went ahead and trial fitted that.

I'm waiting on some more composite screws from R&G in Germany before I can mount that to the cell.

I've added a big block of micro to the leading edge section of the wing (between the tank and wing edge). When I go to put the front pin bearing in I will drill out an appropriate sized hole in the micro then add flock to the bearing and put the wings on. I got this technique from Pete - sounds like a much less messy and stronger solution than the factory suggestion.



The oil cooler now has it's hoses fitted. I've had to order some more 'Cool sleeve' as the first one I ordered was a bit big for the job. Space is a little restricted at the firewall so I've got to do some more thinking here about what to do regarding fittings through the firewall.

I spent about 1 hour carving out flock from the fuel overflow drain hole - a bit stupid of me to not think about the fitting when I was bonding this in. Oh well lesson learned!

I made a start with the 2 remaining composite screws I had to hold the hoses in place. As you can see after bonding in the right place 2 P-clips do the job nicely.

The fuel pumps tray is now attached and so I was able to fit the final feed line to them also (from the fuel selector).

I've built some fiberglass brackets for the inside of the fuel tank - these are to stop the flop tube fittings from moving up and down and thereby coming loose. Vans use a small metal bracket for this job and lockwire the fittings as there was a case of one coming loose. I've used Retaining Loctite on 2 of the fittings then left the one that screws onto the bulkhead pass through so I can take the fitting off should I ever need to.

The brackets will be bonded in with flock - I was going to do this job yesterday but didn't as I found out I didn't have a spanner that would fit inside the fuel tank (and also fit the locknut for the feed line bulkhead). I'll buy an appropriate spanner this week and get that job done before the weekend. So I can do both these jobs at the same time.

As you can see I also have to think about the fuel overflow vent line - it will have to be bonded to the top of the tank - so that it does not obstruct the flop tube. I'll do this when I do the other end - which needs to be bonded inside to the aft side of the fuel filler hole.

Fine Filter position

Front view

Fuel overflow drain - fitting fits now!

Prepping the wing for the block of micro (for the front wing pin bearing)

Oil cooler with it's hoses fitted - more cool sleeve to come

Block of micro

P-clips on composite screw for holding hoses in place

Making progress here. Final feed line fitted to fuel pumps

Brackets for the fuel tanks - to hold the flop tube fittings in place and prevent movement.

Fuel overflow/vent line - clears flop tube okay - will need bonding to tank here.

Flop tube bracket - with slot cut in for fitting.

Trial fitting inside the tank before bonding in.