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Thunder Tiger 35% Extra 260 Build Blog


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Posted by Gary Manuel on 09/02/2017 11:32:36:
Posted by Rich2 on 09/02/2017 11:31:18:

Does that include the rudder and spinner?

You've got me thinking now. I'll measure it later today.

Edit - 97 inches rudder to spinner. Specs say 88 inches, which must exclude the rudder.

Edited By Gary Manuel on 09/02/2017 11:40:54

You will have to let me know when you want it picking up Gary, if it wont fit in.......wink there is always a plan B....

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Had a bit of time, so I've finished the exhaust mounting and cowl cutting.

Cardboard templates taped to fuselage side to mark the exhaust pipe positions.

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.... and the choke operating rod.

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..... and the hole for accessing the needles.

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Exhaust pipes twisted so that the ends are not in the way, allowing cowl to be put back on and marked through the templates.

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I'm having second thoughts about the hole for the needles......

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...... it's not in an ideal place.

I think I'll remove the cowl if I need to adjust the needles at any time. I'm not a "needle twiddler".

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Cowl ready for cutting.

dscn5270.jpg

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This diaphragm pressure nipple needs to be ....

dscn5271.jpg

.... routed to somewhere that isn't exposed to variable air pressure as found inside the cowl.

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This will do nicely.

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Exhaust manifold secured using NordLoc washers.

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Exhaust pipes connected to the headers.

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Fuel overflow secured and routed out of the bottom of the plane.

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Choke rod.

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Finished cowl.

25mm grommets used for exhaust pipe and 20mm grommet used for choke rod.

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Yes Rich - 2 piece cowl.

I'm still thinking what type of screws / bolts to use for fixing the 2 halves together. The supplied canopy screws are not really up to the job.

I'm going to give a grommet the "soldering iron test" and maybe even the "blowtorch" test before I try starting the engine.

May need to find some silicone grommets?

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I've had a read-up about grommet material.

Most of them (including mine) are made from PVC, which starts to decompose at 140C and melt at 160C. Some are natural rubber which is only good for up to about 100C. Not much use if it comes into contact with a hot exhaust pipe then.

The rubber strip used at the bottom of Page 1 of Adrian Smith's thread HERE, got me thinking about using using something similar, but I think that will have the same temperature issues.

I've found THIS stuff, which is made from Platinum cured Silicone. It should be good for up to 230C - 250C. It will also allow me to cut the holes to any shape / size I want. The 25mm grommets I've used at the moment only have about 3mm clearance all round. I'd like double or treble that to allow for vibration and expansion.

 

Edit - here's a LINK to Silex Website

Edited By Gary Manuel on 19/02/2017 15:35:06

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