Wednesday, 27 April 2016


Week 246 - Fuse base bonding

Hours to date: 2510.5

Enough faffing - time to bond on the fuse base!

A few more complications on this job for me because of my mods.

The oil cooler being the main one - everything has to line up mm perfect - the holes I made previously helped greatly to hold the panel in the correct position while it set. Not to mention the 12 clamps, 2 tie down straps and numerous bits of tape and other weights to hold it down.

Doing this job all by myself felt a little like a 'race against time' as you have to mix up lots of flock and micro and it is starting to go off by the time it is ready for the base to go on. From memory I used 400 grams of resin worth of micro and 150 grams of resin worth of flock for the job.

Enough jibber-jabber from me - I'll let the photos do the talking.

Throttle mount and cover painted and reinstalled.

Muffler back on after end mod.

Muffler now follows the profile of the fuse and cowling, giving good clearance.

I set the flaps to 30 degrees down to allow space for the fiberglass reinforcing tape on the edges.

Oil cooler scoop fitting very nicely to inlet duct. Will put a load of RTV on the joining faces when I go to install this for the final time - that should provide an air tight seal.

All flocked/microed/RTVed up and ready for the base to go on. The cardboard boxes are just to hold the base clear until I put the fresh air vent drain tube through it's hole from the inside. The boxes also allowed me to lower the fuse base down progressively as I was working by myself.

As you can see I piled the micro high so it was sure to contact the base for a good bond. This turned out to be just about the right amount - it oozed out the sides (inside) when I checked afterwards. Also note copious amounts of RTV on the rear outlet duct joining face for a good air tight seal to the base.

I borrowed a few clamps from my mate but still could have done with some more - get hold of as many as you can for this job.

Memory foam pillows under the Jerry cans help to distribute the weight evenly. A few shot bags would do the same job. I used old Acetone cans (on the left) filled with water to weigh down the side where I didn't have enough clamps.

Front fits pretty good - still some gaps in the leading edge though.

Other side at the front.

Back Port side - big gaps

Back Starboard side - not so bad.

Time to connect up the cowl flap with it's cockpit control knob. My hand only just fits through the access panel and I had to work blind to do the connection.

Cowl flap control all connected up.

Inside of the leading edges - I decided to use 2 layers of carbon to strengthen this area and allow for flock to be used on the outside to fill the holes between the fuse and base panel. This has worked out well and is now very strong.

Hoisted up so I can make a flange for the top access panel - last one to do!

Access panel in place to get the flange to bond in the correct position.

Thursday, 21 April 2016

Week 245 - Fuse base prep

Hours to date: 2482.25

Preparations continue for the fuselage base. Everything must be tickity-boo before it is bonded on.

Taking the advice of the local UL Power agent, Mark from Galaxy Microlights, I have fitted Dowty type washers to the fuel pumps. My inspector Rex also agreed this was a good idea. They seal better than the copper type washers and can be reused.

I've also been profiling the root rib on the fuse at the bottom to line up with the wing profile. Actually it should be about 2mm lower to allow for the fuse base thickness and glass reinforcing to come. We don't want to be changing the profile of the wing to fit the fuse base, the wing shape is critical, the fuse base not so much.

I spent 5 hours getting the spinner gap plates profiled to fit the prop, yes I was working very slowly here, a little at a time. We now have a perfect gap to the prop.

The next big job was getting the wing auto connect electrics sorted out. 

Honestly if I knew then what I know now I would not bother with this set up. It is a lot of hassle and work to install and only really of benefit if you are taking your wings on and off regularly. If I could go back in time I would just opt for a simple Molex connector. These connectors were very expensive too so I decided to stick with plan A and go ahead and use them.

See the pics below for how to fit them.

I spent a good deal of time sorting out the wing fitting while I was doing this job as I had not previously fitted the wings with the pins in and the flaps on. As you know I made my flap pins too long on purpose and then trimmed them back to fit. I also noticed that the flap itself was contacting the flap drive on the fuse in the middle so that needed a bit of trimming too. All good now, both wings fit on nicely with the pins in.

I've had to have the muffler modified too. It was just too close to the cowling and there should be a good 1 inch of space. So I got CKT Engineering ( in Devon to cut the ends off and weld up the gap. They have made a brilliant job of it. See the pics below. Highly recommended company to deal with.

Hopefully by the next blog post we should have the fuselage base bonded on.

Dowty type washers and a copper one on top to show the difference.

Early look at the fuse base fitting. As per the manual they say to employ tie downs to pull the base down snug.

Profiling the fuse root rib to the wing - as you can see it is a little bit lower to allow for the base.

Spinner gap plates finally done. Profiled to the lower edge of the prop.

Fuel pumps with Dowty washers.

Wing electrics auto connectors. One on the fuse root (at right) is a 'floating' type to allow for slight movement.

Fuse base is fitting better here - still some more tweaks to go.

How to fit the electric connectors. Mount wing to fuse and scribe the position through the hole made for the root rib connector part.

Cut out hole to allow for the wing connector part to fit with it's carbon plate then tape in place and mount wings again to make sure position is right before scribing the carbon plate area.

Only cut through the outside layer of carbon and then dig out the honeycomb inside.

Now you are ready to bond in the carbon plate with flock. Mount the wings to ensure position is correct while the flock bonds.

You will end up with something like this.

Wiring on the inside of the fuse root rib part of the connector. 3 small wires for the fuel level sender and one larger wire for the earth from the fuel tank.

On fitting the wings I discovered that the flap drive was contacting the flap outer near the pin so more Dremel work was needed here.

Every fitting on the underside of the fuse has been checked for tightness and then marked with Torque Seal. This helps with inspecting in the future as any movement of a fitting will break the Torque seal.

Painting the throttle cover and touching up some other parts.

Painting the throttle area. It would be a real pain to fit the throttle after the fuse base is on, so it's best to do it now.

Mod to muffler. Supreme welding from CKT engineering.

Muffler now fits the shape of the cowl better and will have at least 1 inch clearance.

Friday, 8 April 2016

Week 243 - Horz Stabs, Spinner, Alternator Fan and Visit from Inspector

Hours to date: 2437.0

Both horizontal stabilizers are nearly done. Just sorting out the transitions to the root rib on the bottom of them now with micro.

You'll notice on my second stab I put a little more flock on and let it ooze out - this is because I had a couple of very small gaps in the previous one. Better to have too much flock than too little here - you can always sand off the excess.

A top tip to get the stabs on and off easily is to use a little WD40 on the pins, tube and bearings (be careful not to get it on anything else as it won't bond otherwise). I spray some on a paper towel then apply that with the towel onto the pins etc. Works a treat!

Both fail safe carbon brackets are done and drilled now - they seem like a really good solution (if you are not rigging and de-rigging all the time). Solid as hell and easy to put the M5 screw in rather than faffing with the pin (even tough I will still use the pin). I decided not to cut a thread and instead will just use a nylock on the inside to secure the screw in place.

I spent some time making some spinner gap plates up too - not profiled to the prop yet but the basic shape is done. I used a piece of stiff cardboard covered in packing tape and then screwed into place using the spinner screws as a mold. As the fabric pushes up over the edge I used a runny flock mixture in the edge to fill that gap and then sanded down the carbon on top afterwards to give a flush edge with the rest of the spinner.

As I had flipped the fuse over I decided it was a good time to replace the alternator cooling fan plate on the engine. Yes UL Power have changed the design yet again! Hopefully this will be the final change. A fairly easy job to do with the fuse upside down and the muffler off. Bolts should be torqued to 10NM.

As you can see below the design of the old one was a bit crap as the 'meat' either side of the holes was much too small. As a rule it should be at least the diameter of the hole either side. Sure enough UL have found the old design to be cracking.

Today I had a visit from Rex my inspector and he was very pleased with my progress and was full of praise for my workmanship.

We ended the day by visiting the Shuttleworth collection together and watching the Hurricane do an impromptu display. Happy days!

Preparation now begins for installing the fuselage base.

Horizontal Stab after filling the edge gap with flock.

Horizontal stab fail safe securing mod after sanding down flush with the edge (pre drilling though).

Adding micro to the transition area - this is later sanded to give a perfectly smooth transition between the horizontal stab and the fuse.

Oil inspection door after filling and painting with white primer.

Horizontal stab transition after sanding.

M5 screw in place for fail safe horz stab connection.

Horizontal Stab gap in the end is very small - less than 1 mm

Added more flock this time for the second gap fill.

Making up the spinner gap plates - 4 layers of carbon used.

Yet another 4 layer stack of carbon on the front of the cowl to allow it to be chamfered from the outside to clear the spinner.

Spinner gap plate before profiling to the prop on the top - otherwise fits pretty good.

Rex inspecting my work.

Replacing the alternator fan plate. Using the prop flange gizmo to rotate the engine here.

Access is okay if you remove the muffler and work with the fuse upside down.

New design plate on the left, old one on the right.

Old design is a bit crap as you can see there is not enough 'meat' around these securing holes. No wonder they cracked.