Friday 2 October 2015

Week 216 - Throttle and Wheel Spats

Hours to date: 2010.75

A much more positive 2 weeks this time.

I found and fixed the ECU fuse blowing fault. It was my error in connecting one of the sensor wires to earth.

I received a new fuel pump, fitted and tested that. All is now working well and with no leaks. You really have to do up the copper washers quite tight for them to seal effectively.

I've made a start on the throttle - it's going to end up looking exactly like Pete's set up - so I take back what I said about Pete's setup looking too complicated!

At the engine end is a rose jointed rod end - with a threaded inside which will be connected to the throttle. A spacer is required to put this joint away from conflicting with the throttle arm as it moves. I made the spacer out of some Ali tube I had lying about.

On the inside of the cockpit I have begun to think about where the throttle will go. From an ergonomic point of view - redoing the throttle - has been a bit of a blessing in disguise as previously my elbow was hitting the back of the cockpit when I pulled the lever to idle - in fact I had to bend my wrist slightly to get the throttle to full idle which was not comfortable. With this new set up I should have free movement and in a better range for my arm as it will be further forward.

There have been a couple of other fixes for this problem. The French Twister used a (to me) very complicated and unproven modification which increased the effective travel of the throttle at the engine end. I am against this type of thing on principle - especially for such a critical component as the throttle. In the USA Deb Van Treuren has been able to fix her throttle by just cutting out the slot in the cockpit to increase the travel of the lever - which is a good solution if the ergonomics permit it - unfortunately for me they don't so that's why I'm going for the Vernier set up.

Onto the wheel spats.

Fairly straightforward job this - but as always on the Twister - an added complication!

I'm guessing the brake set up has changed since the molds were made for the wheel spats as the small cover does not fix on because of confliction from brake parts protruding - see photos below. 

Also I found that the Ali bracket that fixes the wheel spat on seems to be out of position - too much bracket at the front and too little at the back. Again I see that the French Twister had this same issue. I have gone for a similar fix to the problem by creating an add on bracket at the back to extend the bracket so it lies underneath the wheel spat.

The M6 dome head screws will be fixed on by the use of nut plates riveted to the back of this bracket set up. Instead of the normal 2 I will have 3. And despite the instructions saying to use self tapping screws in the rest of the cover I will go for M4 dome head screws into nut plates - a more long term solution than self tappers which tend to wear holes and pull out of fiberglass over time.

The throttle itself has arrived in the post so I will get going on installing that over the next week or two. Hopefully then we will be ready to attempt another engine run.

New throttle - engine end

Ditto

Carbon bracket to attach throttle in cockpit - just rough positioning with plasticine here.

Initial positioning. Tailplane should be horizontal to measure distance from back of wheel spat to the ground - 220mm - not shown correctly here as I was just starting the job.

Hole made to clear brake protrusions filled with plasticine shaped for later glassing.

Back is protected with cardboard - to stop plasticine from pushing through.

Spat in place with bracket mod.

Ditto with spat removed.

You can see the brake protrusions here.

Ditto - they don't stick out by much but they do stick out - hence the mod needed.

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