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#1605866
Kati's 20 year old 'flexible' tubing from pitot head to instrument panel has hardened and needs replacement.

1 Any recommendations for replacement material that will be acceptable to the LAA, and supplier?

2 Any hints/tips for getting the section through the wing? There are 3 or 4 4"(guess) dia access panels along the wing, and I'm assuming that the original tube is tied/fixed in place so it won't be possible to pull the old one out using it to pull the new tube or a piece of sting through. My domestic drain rods are a bit large to be of any assistance!
#1605937
Semi-rigid nylon or PVC tubing is most commonly used. Maybe try LAS https://www.lasaero.com/products/article/I00I217XF
I like the 1/4" push-on fittings. They seal very well and make hooking up a lot easier.

Can you maybe put a few extra inspection rings on the under-wing fabric to gain access, assuming you're talking about a rag-wing.
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#1606135
Charles Hunt wrote:Kati's 20 year old 'flexible' tubing from pitot head to instrument panel has hardened and needs replacement.

2 Any hints/tips for getting the section through the wing? There are 3 or 4 4"(guess) dia access panels along the wing, and I'm assuming that the original tube is tied/fixed in place so it won't be possible to pull the old one out using it to pull the new tube or a piece of sting through. My domestic drain rods are a bit large to be of any assistance!



will these 10m Mighty Rod Cable Rod Set help?
#1606273
I've no idea what sort of aeroplane your 'Katie' is.
However if you can abandon the old tubing and still find a feasible new route for a new flex pipe,through the wing etc. etc. On the Rans I had help from some of that old fashioned coiled curtain wire to reach places I could just about see if not touch.

mike hallam.
#1606399
I that case it's a doddle Charles.

I've done both the Rans S4 and more recently my S6-116. You should have at least wing two zip fasteners and it was quite possible to tow in the new clear plastic fish tank/beer makers hose. Use a diameter that's convenient (not too thin walled) as there's no actual airflow, simply pressure to convey.
The worst bit to think of initially was how to fix it to the Ali pitot. That's where the curtain wire was wizard. Push pitot back inside for re-use then the curtain wire back through its spar hole from outside. Looking up inside the wing through the zip gap you can see & get hold of it.
With the plastic tube generally ready in approx. position have the outer end poking outside through zip gap and there it's so easy to wire lock your new hose onto the rear of the pitot tube, then push the pitot onto curtain wire. Sometimes a thin lick of masking tape witll help. keep it there for the next op.
Slowly wiggle curtain wire in reverse pulling from outside and jiggle the Ali tube through the spar to the outside world.
I now keep the Ali tube from sliding back inside with an external wired on little piece of gash hose. In fact in the hangar to avoid damage or a bent tube from careless fol I slide it back nealy all the way gently pushing the wired on gash hose along.
Works well. If you P.M. me I'll send the releant RansMail with pic's. Find my address under Jackrell's Farm in AFE or Pooleys .

mike hallam.
#1606435
Except that the S7 has conventional doped fabric rather than zipped 'skins'. As mentioned above there are a few access panels on the front of the wing, but it will be a bit experimental trying to get past the fuel tank.

Oh, but first I need the tubing, Parcelforce claim to have tried delivery Saturday lunch time and left a card, but there is no card to be found. electronic query sent, stand by........................
#1607675
Tried on thursday with bits of string, wire, and curtain wire. All were too flexible, drooped and snagged on ribs. Did manage to feed some string along the leading edge using some 300mm x 10mm timber I had to hand, but as KATI has a wing fold, the tube has to make it to the rear corner, missing the fuel tank on the way.

I dropped into a Homebase in the evening thinking dowel or perhaps garden cane. The latter was £1 for 10 x 8 foot lengths; and worked brilliantly today.

In the beginning I fed some string through, and tried to pull the hose back; but it still kept snagging. In the end I whittled the end of the cane slightly so the tube could be fitted on, withdrew the cane, and the tube came along without any problems.

Bad news - although I bought 40 foot of tube, the static line needed doing as well, so I ended up 15 foot short. Oh and the ASI was a few mph out going up the scale, but read 8 mph high at 40 mph, so a new one will be on order shortly. Coming from Warriors, I think in knots and flight plan in Nautical miles, any reason not to change to knots? Adjusting arc speeds and placards accordingly.
#1607686
Well done that man !

Just remember if, pro temp, static is open to cabin suction pressure the ASI would over read 'X'.
I have mounted a fuselage side static as has another S6 owner I cribbed the idea off to reduce reading error to 2 o3 3 mph at 100, instead of6or m0re exaggeration.
Again explained in a back number of RansMail. (free blog available).

mike hallam
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