Thursday, 20 November 2014

Week 171 - Headrest and Firewall

Hours to date: 1527.75

Things are moving forward with the headrest.

As you'll see below I've made up a bracket for the Dzus quick release fastener and bonded it to the back of the cockpit area.

For those of you wondering why I didn't do this before painting the cockpit - it's called impatience :)

I’ve also got around to fixing the engine mount hole that was out (by about 6mm). I just filled in the old hole with flock then thought it would be an easy case of drilling a new hole. But as usual, nothing is easy! The drill was tending to migrate towards the flock as that is a softer material than the carbon. This would have elongated the hole in the flock area - no good. So I ending up using the Dremel and about 1.5 hours later had a hole that was perfect.

With that done it was time to start on protecting the firewall. For me the best material for this is Fibrefrax. It is very easy to work with - just cut with scissors and glue with a very high temp glue. No-one would import the glue made by Fibrefrax from the USA because it is deemed too dangerous. I found a glue used to repair fireplaces and exhausts - which is good for 1200 degrees C. The Fibrefrax is good for 1300 degrees C. Easily exceeding the FAA requirements of 1100 degrees C. A sheet of stainless steel would do the same job but would be very difficult to shape around the edges. Also the outside of the fuselage that will sit below the cowling needs protecting too. I will do this with the thinner 1/16th Fibrefrax and cover that with Ali 'Cool-it' tape.

After all this is done then I will cover the lot with a heat blanket (shown below) which is fibreglass on one side and ali on the other. This is purely for cosmetic and practical reasons as the fibrefrax would easily get dirty and soak up oil or other fluids.

I've got the 1/16th Fibrefrax on order so I'll probably get on with the battery and finish up the headrest next.

Bracket for headrest with Dzus fastener and spring back shown for position.

Spring riveted to back of bracket


Figuring out where to put the bracket

Engine mount with top right hole not done.

1.5 hours later with hole all done.

Blue tape shows how far back cowling will go.

Heat blanket that will go over the Fibrefrax - backside shown on the left


Very high temp glue - good for 1200 degrees C.

Gluing on the Fibrefrax.

Headrest bracket bonded in with flock and 2 layers of carbon.

Thursday, 13 November 2014

Week 170 - Trim, Control Column and Headrest

Hours to date: 1519.25

After fitting everything remaining on the Rudder pedals I was a bit nervous and pessimistic (you have to be this way on a Twister) that things would work.

As it turns out they worked perfectly - no adjustment needed and the operation is surprisingly light. I'm really pleased with the way this turned out.

Onto the Elevator actuating (control column) and Trim.

This all went in fairly easily so there's not much to report really - except the trim does not seem to be in the neutral range when set in it's middle setting. Not sure why this is so I'm going to have to figure that one out.

My Trim indicator solution is just to mark the middle of the exposed bit of wire and then make corresponding marks on the fuselage side.

I've also started on a headrest - yes dear readers another mod!

I've got to attach it to the seat with a hinge then build a small bracket at the top of the fuse to allow for a Quick release fastener to be installed. (A screw head Dzus type).

Next job will most likely be either the battery or firewall and engine mount.

Rudder pedals all done - working perfectly

Carbon mount added to Micro block now

Cable ends

Fitted the elevator pushrod bearings

Control column installed

Trim indicator solution - wire and fuse are yet to be marked

Trim installed.


Some confliction here as the range is not right at the moment.

Elevator actuating pushrod

Rubbing on the left side - need to Dremel that gap out a tad


Leather covered foam block to be added later.

Wednesday, 5 November 2014

Week 169 - Rudder pedals

Hours to date: 1511.75

Not a great deal of progress in the last 2 weeks as I've had a friend staying from New Zealand - so more beer got drunk than plane got built.

Back into it now.

The second coat of cockpit paint went on well and I'm pleased with the results.

As you'll see below I've started to install things back into the cockpit area.

The first major assembly is the Rudder pedals which I've almost finished.

No major 'gotchas' so far on this job. I did struggle to figure out which way the spring went - this is the spring that keeps the pedal adjustment lever in place.

I'll try to post a better picture of that next time. (Basically it's facing downwards with the closed end at the top acting on the rear of the lever.)

I managed to Nicopress the front hooks for the rudder cables with the tool in the vice (and the cockpit positioned close to the bench). Of course I was unable to do the same for the rear ones as they don't have much slack left in them by the time the front ones are on. Don't forget to put some heat shrink on the cable before Nicopressing your sleeves - then slide it over the sleeve and wire end and apply heat with a gun - this makes for a neater job and helps avoid cut fingers on the wire end later.

In fact I was paranoid that I wouldn't have enough cable to do the job as my mod extending the safety cell forward would use up another 250mm. As it turns out I just had enough to do the job - with only 90mm or so of cable left over on each side after finishing the Nicopress hooks at the rear.

I found the best way to cut the cable is using the Dremel with a cutting disc. Use a little masking tape on the area where you're cutting to make it a clean cut. Use almost no pressure - let the disc do the work (at a high speed).

I've not put the carbon block on the front of the pedals yet - this gets screwed into the micro block at the front of the cell. After I've done that the job will be pretty much finished.

I'll probably have a go at the Trim and Control column next.

Adjustment cable in place - no spring though at this stage.

Looking forward after second coat of paint

Looking rearward

Getting there with Rudder pedals

Carbon block not in place yet but everything else is done.

Hooks and Nicopress sleeve at the rear - use heat shrink to make a neat job of it.

Cable left over - only just enough to do the job