Week 103 - Tailwheel mudguards and engine mount

Hours to date: 1058.25

As you will see below the Twister finally got to sit on it's tailwheel for the first time.

I've been clamping the shroud from the sides every now and then and leaving it overnight - it seems to be a much better shape now - fits the rudder much closer. I think I will put some carbon down the inside and clamp the lot together to make it take on the absolute correct shape.

I made up some mudguards - a curved one for the front. Made out of a glass sandwich (Nomex). Fits nicely and I glassed that in.

Inside the rudder I used a rib sent by the factory - but it was straight - so it did not make it all the way to the end of the rudder. I've made a curved section and glassed that in too. 

While I had the tail outside and had the space at the firewall I decided to trial fit the engine mount.

Well as you can see three of the holes fit okay but the fourth one is a little out. By about 6mm. I haven't asked Pete how to fix this yet but I am guessing it will be along the lines of - Flock in the hole then drill out a new one. I'll share his advice when I get it.

I managed to get the starboard elevator hex out without destroying it.

It will need a little bit of carbon on it but is otherwise intact. Fixing this back in the right place will have to wait until I can get access to a work area that allows me to leave both tailplanes on for 24 hours (so the flock can set).

I've also taken the decision to re-do both securing pins and front bearings for both tailplanes. I made a screw up with alignment and I am just not happy with them. The Port one is only out by the tiniest amount but I will still redo both sides as they must be perfect.

My mistake was to get too fixated on the pin itself - that job required a bit of thought. In doing so I failed to realise that the alignment was not perfect at the time and blindly went ahead and bonded in the front bearings. Not good.

I think the right way to do it is to align the elevator in the neutral position at the outboard end with a clamp. Then move the tailplane up or down until the root end of the elevator trailing edge lines up with the root end of the fuselage trailing edge.

So just when I thought I was getting done with the tail - there's more work to do! My fault entirely and I have learned a lesson because of it.

I've still got to add some tailwheel 'stops' that will limit the rudder travel to the factory specs. 190mm + or - 15mm either side. Measured at 400mm from pivot point. These will just be carbon blocks bonded on the front mudguard.

Sitting on it's tailwheel for the first time.

Shroud starting to fit better to the rudder

Engine mount trial fit

One hole is out...

Tailwheel front mudguard

Getting the hex out of the starboard elevator

Rudder mudguard - straight section then curved section added.

Front mudguard glassed in

Ditto

Hex removed

French Twister takes to the air

The first Twister built in France has taken it's maiden flight.

Same spec as mine - Integrated tailwheel, fixed gear with UL260iSA power.

I will be interested to hear what performance figures they get - once everything has settled down and the engine is run in.

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.

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

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

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.

Bummer!

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...

Shroud

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.

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

Ditto 

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.

Week 97 - Horz Stab pins

Hours to date: 985.75

Onto bonding the horz stab pins themselves now.

Quite a focusing job this one.

As you will see below I put parcel tape everywhere in case any flock would run out.

After establishing where the hole would be for the pin in the Horz Stab root rib I drilled that out and made it a touch bigger - about 12mm (to allow for any movement of the horz stab to set it on the right angle).

I made a little funnel out of a mixing cup. Then mixed up some fairly runny flock (unlike the usual consistency you are aiming for - 'peanut butter'). So it would flow into the cavity in the horz stab.

After that it was just a case of pushing the horz stab home fully and rotating the fuse to as vertical as possible (so the flock wouldn't run out).

I left it like this for 5 hours until the flock had started to go off before rotating it back to the horizontal (I only did this so I could close the garage door).

Bit nervous the next day but it was all fine and the horz stab released out fine (after taking the pin wire out).

The wire goes in very easily now and feels very solid and secure - so I'm glad I went with Pete's bush mod here.

As you can see from the last photo the horz stab on the starboard side does not match very well with the fuselage root. A bit upsetting - not exactly sure how to fix this so will contact Pete about it.

On the Port side it does match up perfectly at the leading edge but then there is another problem - a big gap underneath (will post a photo next week). This will require a lot of body filler to put right - adding to the weight, not good. Also the front pin is way out with the hole drilled by the factory so will require a bit of work to put that right. Frustrating stuff.

Next job may be the elevator hexes - which will be bonded into the elevators and determine the control surface travel - so a bit critical to get right.

Packing tape everywhere

Funnel for pouring runny flock into the cavity.

Going vertical for it to set.

Figuring out where to route the trim cable (and drilling holes for the indicator wire)

First pin done. Not too much overspill of flock.

Onto the second pin

Starboard horz stab leading edge to fuselage root gap.