Wednesday, 31 July 2013

Fuel System Diagram

While we're doing diagrams I thought I'd share this one too.

Drawing this diagram helps me to organise and better plan prior to installation.

I hope someone finds it useful.

You will see that I have not included a Gascolator. (unlike Pete).

All the advice both from UL Power (and Vans) says that unless you can fit a Gascolator at the lowest point in your fuel system then it is pointless.

The lowest point in a Twister is the rear of the fuel tanks (as it is a taildragger) which is where the factory say to fit the drain valves.

This is where you drain off any water that may have collected in the system (the low point).

So fitting a Gascolator to a Twister on the firewall is pointless - even the fuel screen which normally acts as a final filter before injection is pointless as it is coarser than the fine filter supplied by UL Power and fitted further upstream.

Once again - click on the image for a much larger view.

Electrical Diagram

Here is my first attempt at an overall power diagram.

It will most likely change a bit before I am through.

Click on the image below for a much bigger view.

Sunday, 28 July 2013

Week 102 - Lower tailwheel support

Hours to date: 1043.25

After many hours of body filling and sanding I am now happy with the tail shroud. It has a nice and smooth transition to the fuse.

The carbon plates were finally installed in the lower tailwheel area.

I am pretty happy with the way this job went considering the limited access to the inside of the tail.

I've still got the bottom inside edge to flock and glass but this was upside down when I was doing the rest so I've left it till later.

I used a shed-load of flock down the sides of the carbon plates to make a very strong bond between them and the fuse sides.

As you can see I used lots of parcel tape everywhere to stop any flock going on the tailwheel fork or bearings - that would not be good.

Next job will be bonding in a rib which will act as a mud guard for the front section.

The rear mudguard will be another rib bonded into the rudder.

As you will see below I tried drilling out some holes in the rear baggage compartment cover - to make sure I have good through-draft in the cockpit area.

Kevlar has a lot of wonderful properties but 'easy to work with' is not one of them!

As you can see drilling makes a bit of a mess - there is no way to tidy up the holes. So I've cut that section out and replaced it with normal glass (2 layers) which should give a much nicer finish when I drill out the vent holes.

Drilling Kevlar... what a mess

Packing tape everywhere prior to bonding in carbon plates

2 layers of glass to fill the hole - using cardboard wrapped with duct tape as a flat surface

Bonding in the carbon plates

Glass 'window' in Kevlar baggage compartment end cover

Bonded in carbon plates

Still got the lower section to flock and glass - plus a bit of tidying up to do

Tuesday, 23 July 2013

Week 101 - Tail shroud and Rudder clearance

Hours to date: 1034.0

Slight change of plan from last week!

After looking at things more carefully it seems that I had to bond on the tail shroud before the carbon plates. This is because the carbon plates are partly bonded onto the inside of the shroud.

So I went ahead and bonded on the shroud.

With clamps for Africa.

As you can see below they just cleared the garage door - by a small finger width.

I just used a heap of flock and squeezed it down on that. After that was set I got stuck in with the body filler and began smoothing out the interface.

Still got a little more to do here but it's coming along nicely.

Will add some layers of glass on the inside to connect the shroud to fin but to be honest it already feels very secure and rigid.

I've also been working towards fixing the rudder to fin gap.

Adding carbon strips down the outside of the fin at the back to allow for taking material off the inside - which will increase the gap.

First go yielded good results - some more to do though before it is perfect.

May get onto the carbon plates job next - we'll see.

Port side - adding carbon strips to the fin

Gap is good now in the middle position - not perfect when deflected though

The troublesome starboard side - will need a bit more work

Bonding on the shroud - clamps for Africa!

Shroud with body filler partly done

Shroud with body filler - side view

Tuesday, 16 July 2013

Week 100 - Elevators and Tail lower shroud

Hours to date: 1027.0

After getting the hexes set (with 5 min resin) I went ahead and bonded them in with flock surrounding them and then finished off with the carbon ribs I had made up to replace the factory ones.

After all of this when I put them back on - I found that one of them had moved slightly.


So it looks like I will have to redo the starboard side. I may be able to save the fiberglass part of the hex and reuse that - we'll see. Otherwise I feel confident enough to remake one from scratch.

This is a pretty good example of why you need a decent size workshop. I had to change the procedure and used 5 min resin rather than flocking them in as per the manual.

I'm guessing the 5 min resin was not set completely hard before removing (even though I allowed more than an hour for it to set).

You have been warned...

I've started fitting the lower fin shroud too.

I'll flock this on - using clamps to hold it in place. Then put several layers of glass on the inside to join it to the fuse.

I did notice that it doesn't really take the shape of the rudder like Matthias's one does.

I will have to mod it to do so, as at the moment it sticks out quite a way.

Though before I bond the shroud in I will have to install the carbon plates that set the tailwheel in place. So that's the next job.

Factory carbon ribs for elevator - don't fit too good.

So I made my own

All bonded in

Prepping the tail for the lower shroud - you can see how far out the starboard elevator is here...


Bit of a big gap at the front of the tailwheel - may fix that I think

From the right-hand side

Looking from the back you can see the shroud sticks out too far.

Monday, 1 July 2013

Week 98 - Elevator Hexes, Headset jack & Firewall

Hours to date: 1004.75

In a moment of sheer stupidity I bonded in 8 bolts for the battery cover. Then when they were set realised that the cover would never come off as the angles of the bolts were different (due to the curves of the cell).

Not a huge problem though - I just removed the 4 bolts from the top and bottom edges and the cover came off. 4 bolts is more than enough anyway (8 bolts was overkill).

Onto the headset jack socket. A nifty little unit that when mounted makes the jack plugs flush with the edge of the cell and so protected from bumps. After much deliberation I decided where it should go. Just next to my right elbow. I wouldn't want to have it on the lefthand side of the cell as that is the throttle side and your elbow would be constantly hitting it.

Regarding the Starboard Horz Stab to Fuselage gap - after speaking with Pete it was a relatively straightforward fix - micro. Then sand to shape.

I used a piece of clear plastic taped on the root to make it flush with the edge.

Seemed to come out okay. I will use micro to fix the Port side too.

Onto the elevator hexes.

I followed Pete's advice and put plasticine on the rivet end of the ali hexes.

Once again packaging tape was used everywhere as a release. Including on the inside of the horz stab rear rib.

Following the manual on this one (Pete does it differently) I used 5 min resin to set the Port elevator at it's upward limit of 80mm. (this is done with the counterweight lowered to rest on the rib inside the fin).

After that was set I put the other tailplane on and set them both to neutral - with more 5 min resin (not flock as stated in the manual). Clamping them in place.

I do not have the ability to have both tailplanes on inside the garage so setting with flock was not an option for me (it takes 24 hours to cure).

The 5 min resin holds the hexes very securely and I will pour runny flock into the spaces around them as my next job.

After that all that needs doing is bonding in the carbon ribs (which don't fit very well!) into the elevators. Once that is done the only job left on the horz stabs is to bond in the front pin bearing.

While the tail was outside setting I took the opportunity to reinforce the firewall. In the absence of instructions to do so in the manual I used one layer of heavyweight (240g) carbon. (Pete uses glass I think).

Hopefully later on this week I can get the elevators finished off and then get onto the front pin bearings next weekend.

8 bolts in battery cover is 4 too many!

Headset jack socket

Headset jack socket - location in cockpit

Micro on the horz stab fuse root end to fix gap.

Plasticine (orange) and packaging tape as release for hexes

clear plastic on root edge makes for flush edge and easy way to check you have enough micro in place

Port horz stab leading edge - much better fit than starboard

Underneath is not so good - I will use micro on the horz stab to fix this.

Bonding in the hexes with 5 min resin

Garage is a bit small to build a Twister...

Firewall reinforcement

Starboard horz stab fix - sanded down micro

Hexes bonded with 5 min resin. Now to flock them in properly.

1,000 hours

Finally passed 1,000 hours yesterday.

Had a couple of cold ones to celebrate.