Tuesday, 26 November 2013

Week 119 - Wheels and brakes

Hours to date: 1211.5

Onto the wheels and brakes now.

There seems to be some discrepancies in the manual - which has confused me a bit.

Also because I am going for the fixed gear then the section 3 - fuselage - part of the manual talks about doing one thing and then section 8 - Fixed gear - talks about another.

Neither of them seem to make perfect sense.

I've followed what Pete does with the brakes - M6, 20mm screws with Nylocks on the outside. Section 3 of the manual talks about M6 10mm screws - but these would not go through the axle flange and brake (which combined are about 11mm) let alone give enough thread for a nut and washer on the outside.

Note that I've needed to very slightly grind away a 'wedge' on the gear leg to allow the brake to sit fully against the gear leg - we are only talking about 1-2mm here - see photo below.

I've also used an M8 bolt to secure the axle and brake to the gear leg. Section 8 talks about using an M6 bolt - but then says to put an M8 nut on the end of it! So that's clearly an error. Also the stated M6 bolt (55mm) was not included in my kit.

Here's where it gets complicated...

So after fitting the brake and wheel (which is partially held on by the brake disc rotor - which must be bolted to the wheel after putting inside the brake pads) I thought I would go ahead and see how the wheel spat is fitted.

After quite a bit of head scratching it seemed to be that the ali bracket which attaches to the gear leg has 1. An M6 hole where my M8 bolt is and 2. An M8 hole where the centre of the axle is. This would indicate that I need to put an M8 bolt through into the axle - but as you will see below the axle does not have  thread on the inside.

I see on the French Twister they ended up flipping the bracket up the other way and then drilling another hole through the M6 hole in the bracket - right through the gear leg and securing it that way. Then after that they still went back and made a thread in the axle and fitted another large washer and M8 bolt through that to secure the axle.

I am hoping to be able to not have to do that.

I would like to use the existing bracket - but if it means making up a new one - then so be it.

I've also included a photo of what Pete does at the bottom - this is not in the manual - so is another of his mods. Seems to make sense though - the one M8 bolt does not seem enough to hold the axle onto the gear leg.

To be continued...

Brake from the outside

Brake from the inside - angled 120 degrees from black line.

Small wedge that needs cutting into gear leg for brake to sit flush

Wheel in place

Brake disc rotor must be put on brake first then bolted to wheel.

Wheel spat bracket

No thread inside axle...

Position of spat bracket from manual

Confusing part of the manual M6 with a M8 nut

Fuselage part of the manual
What Pete does...

Monday, 18 November 2013

Week 118 - Various

Hours to date: 1200.5

Well Pete has still not made up the canopy parts I need so I've moved onto other jobs.

Kind of a blessing in disguise actually as I am now doing all the little jobs that I've not got around to previously.

The baggage tray is finished - I'm pleased with the way it turned out.

I discussed the throttle/brake assembly with Pete and he agreed it needed more than just flock to hold it in place so I'll put a couple of bolts through there. More worryingly the throttle cable in it's current position would have to go through the spar tunnel (indeed Pete says that what people end up doing - drilling a hole through the spar tunnel). Obviously I am not keen on this idea.

I see the French Twister had the assembly round the other way - so that the throttle is on the outside - this puts the cable in a better position so I will most likely follow suit here.

For such a critical component it seems to have not been thought out properly in the design stage. I'll be spending a bit of time on this as for me the throttle action (and security) must be perfect.

Another thing that Johan pointed out to me is that the throttle friction cannot be adjusted in flight - in fact the access to the friction is only through the bottom of the aircraft via an inspection panel.

For these reasons you can understand why Pete has switched to a vernier type throttle.

Another couple of jobs I did are: Reinforcing the rest of the main gear posts - I'd only done one side before as that was what the manual indicated but I noticed that the French Twister had the whole post reinforced. This doesn't add any weight really so I've done the same. The manual can also be interpreted this way to do this. The other job is making an access panel for the connection of my cowl flap - where access is very limited so it's a bit of a necessity.

I've also installed the radio and transponder antenna cables - these follow the route of the rudder cable guides. This job is great way to take all the skin off your knuckles!

I determined the position of the flap drive 'box' and have used the composite fasteners I got from Germany to put in some mounting posts for this. They are stuck on with flock and I put a single layer of glass over the top as Pete does (although the fastener manufacturer says that flock alone is enough).

Next up is the ammeter shunt - see photo below for location. I'm making a cover for this as well - the ammeter shunt carries the same charge as the terminals of the battery so it must never come into contact with anything else. Given this - it's a wonder that they don't supply a cover with them.

Finally I've installed 3 warning lights (red LEDs) into the panel. These are for 1. Starter operating (a UK CAA requirement), 2. ECU fault and 3. Low volts warning (both of which are required for the UL Power engine setup.)

Next up I will work on the main gear and wheels and brakes I think. I'm having a new spacer made up for the hub that is missing one (!) by my friend in New Zealand - Peter Boettcher - Thanks Peter!

Baggage tray all done

Carbon tabs on the side fixes it nicely in place

Throttle cable position - red line indicates current position

Front of throttle assembly - not much room before spar tunnel

Access panel for cowl flap connection

Carbon reinforcement around main gear post

Flap 'box' mounting posts

Radio and Transponder antenna cables

Ammeter shunt location

3 Red LED warning lights added to panel

Monday, 4 November 2013

Week 116 - Baggage tray continued

Hours to date: 1182.5

Not a great deal of progress this week, but the baggage tray is almost done.

I put a layer of carbon over the edges where the micro was (top and bottom) - this will make it much less likely to get damaged in service, the micro is a little brittle on it's own.

Then I added 4 carbon brackets for fixing to the cell.

After these are set I will round off the corners and drill through them and the cell - before putting some fixings on the outside - the same spike-type nutplates that I used on the cell end cover.

The manual calls for a Velcro fixing of the baggage tray only. Firstly I don't know how you would do that as the tray sits horizontally on an angled cell edge - so how would that work? Secondly I don't think velcro would be enough - I prefer to have it properly secure. The thought of it coming loose during aeros and then fouling the controls below bothers me. So that's why I'm going for the carbon fixing brackets. I've also flocked a couple of small plywood blocks under the port side to support it, should the brackets ever break. On the starboard side the battery cover already acts as a 'stop'.

The seat required a little more work as you will see below the right hand side does not actually make contact with the cell floor - so I've added a heap of micro under there. I've also added some more micro to the front edges as they got damaged when I was taking the seat out the first time.

I was a little too impatient taking the seat out - with releasing a layup it is always best to use slow steady pressure. Lesson learned.

Once both the baggage tray and seat are finalised I will move onto the canopy - unfortunately Pete is taking a very long time to organise the canopy parts that I need. I'll chase him again this week.

A good fitting baggage tray - with carbon now covering the micro extended edges

Seat not touching cell on right hand side - I've put micro under there to fill the gap.

4 carbon brackets to secure the tray to the cell.