Fuel treatment?

[Dafydd Llewellyn]

Great. Now tell us how we buy it.

 

 

[Guest Andys@coffs]

Guys.....those using 98 and suffering bad smells......Dafydd suggested that its the aromatics passing through the fuel lines....In previous threads we have also discussed the fact that full tank sloshing isn't as good at handling aromatics as we might wish. Once the sloshing is removed then the tank is likely no longer fuel impregnable and no matter what fuel you put in it you will likely have the same issue unless it is resloshed assuming your manufacturer supports such an approach.

 

My L2 had his J230 with passenger seat header tank exhibit exactly this behaviour when he switched temporarily to 98 and he determined that the only approach to solve this problem once the sloshing was damaged, that was acceptable to him was to replace the header tank......not exactly a minor undertaking IMHO so I'll stick to the Avgas for the moment. Also the things added to 98 to make it move from 95 to 98 read like the who's who in cancer inducing chemicals......best I not be breathing these if I can avoid it...... Toluene is not good stuff! http://en.wikipedia.org/wiki/Toluene_toxicity

 

Andy

 

 

[dazza 38]

Great. Now tell us how we buy it.

I'm not sure where people can buy it, it is black and has a fabric sheath like a braided hose. I have always used Caltex vortex 95 and 98 in my bike and have never had a issue. Great stuff.

 

 

[Dafydd Llewellyn]

So you go to the bike shop & say, can you sell me some of that black, braid sheathed fuel hose, eh? I'm sure CASA would be very relaxed about that, if a design signatory approved it . . .

 

 

[AVOCET]

I'm not sure where people can buy it, it is black and has a fabric sheath like a braided hose. I have always used Caltex vortex 95 and 98 in my bike and have never had a issue. Great stuff.

I tried sourcing hi press hose for the SDS, i spoke to lames at parrafield and they suggested pirtec hose , CBC stock a similar orange hose , the specs are on pirtecs web site . Seems to be the stuff they use in motor racing , .i think ill go for the teflon hose when time to replace .

Pirtec wouldn't recommend avgas but said ethanol was ok in their product .

 

It seems to go hard if you let it dry out ,

 

Mike

 

 

[Dafydd Llewellyn]

Guys.....those using 98 and suffering bad smells......Dafydd suggested that its the aromatics passing through the fuel lines....In previous threads we have also discussed the fact that full tank sloshing isn't as good at handling aromatics as we might wish. Once the sloshing is removed then the tank is likely no longer fuel impregnable and no matter what fuel you put in it you will likely have the same issue unless it is resloshed assuming your manufacturer supports such an approach.My L2 had his J230 with passenger seat header tank exhibit exactly this behaviour when he switched temporarily to 98 and he determined that the only approach to solve this problem once the sloshing was damaged, that was acceptable to him was to replace the header tank......not exactly a minor undertaking IMHO so I'll stick to the Avgas for the moment. Also the things added to 98 to make it move from 95 to 98 read like the who's who in cancer inducing chemicals......best I not be breathing these if I can avoid it...... Toluene is not good stuff! http://en.wikipedia.org/wiki/Toluene_toxicity

 

Andy

Aluminium line does not care whether it's 98 or E10 or AVGAS. So that reduces the problem to the fuel pump diaphragm and the carbie float and any fuel filters - and I don't use paper-type fuel filters.

 

 

[AVOCET]

Tri

 

So you go to the bike shop & say, can you sell me some of that black, braid sheathed fuel hose, eh? I'm sure CASA would be very relaxed about that, if a design signatory approved it . . .

tried that , they only stock cheap black stuff made in indoneas?

 

 

[Dafydd Llewellyn]

I tried sourcing hi press hose for the SDS, i spoke to lames at parrafield and they suggested pirtec hose , CBC stock a similar orange hose , the specs are on pirtecs web site . Seems to be the stuff they use in motor racing , .i think ill go for the teflon hose when time to replace .Pirtec wouldn't recommend avgas but said ethanol was ok in their product .

It seems to go hard if you let it dry out ,

 

Mike

Well, AVGAS is mainly straight iso-octane, i.e. NOT an aromatic - so it's much less likely to damage the hoses.

 

 

[dazza 38]

So you go to the bike shop & say, can you sell me some of that black, braid sheathed fuel hose, eh? I'm sure CASA would be very relaxed about that, if a design signatory approved it . . .

Use it on a experimental

 

 

[Dafydd Llewellyn]

Well, one can - but I don't think I will, thanks all the same.

 

 

[AVOCET]

D

 

Well, one can - but I don't think I will, thanks all the same.

Dayfdd , could you explain briefly why its not advisable to use the aluminium fuel fittings in the engine bay ?I can understand that ally fuel line isn't a good idea due to vibration in the engine bay .

Mike

 

 

[Dafydd Llewellyn]

DDayfdd , could you explain briefly why its not advisable to use the aluminium fuel fittings in the engine bay ?I can understand that ally fuel line isn't a good idea due to vibration in the engine bay .

 

Mike

Simple: It's not fire-resistant. Admittedly engine fires are rare, nowadays, but that is largely the result of good practice in regard to fuel systems as a result of WW2 experience. Fuel system fire resistance is built in to aircraft certification design standards:

§ 23.1183 Lines, fittings, and components.

 

(a) Except as provided in paragraph (b) of this section, each component, line, and fitting carrying flammable fluids, gas, or air in any area subject to engine fire conditions must be at least fire resistant, except that flammable fluid tanks and supports which are part of and attached to the engine must be fireproof or be enclosed by a fireproof shield unless damage by fire to any non-fireproof part will not cause leakage or spillage of flammable fluid. Components must be shielded or located so as to safeguard against the ignition of leaking flammable fluid. Flexible hose assemblies (hose and end fittings) must be shown to be suitable for the particular application. An integral oil sump of less than 25–quart capacity on a reciprocating engine need not be fireproof nor be enclosed by a fireproof shield.

 

 

 

(b) Paragraph (a) of this section does not apply to—

 

 

 

(1) Lines, fittings, and components which are already approved as part of a type certificated engine; and

 

 

 

(2) Vent and drain lines, and their fittings, whose failure will not result in, or add to, a fire hazard.

 

Normal practice is to use a steel bulkhead fitting through the firewall, and run fire-resistant lines from there to the engine.

 

("Fire resistant" is defined in FAR Part 1 - from memory, it requires the item to be capable of resting 1100 degrees F for 15 minutes)

 

Good practice is to minimise the fuel system components forward of the firewall, (e.g. fuel filters, electric fuel pumps, etc), and to use hose that is essentially high-pressure hydraulic line - which takes a while to burn through - with fire-sleeve over it; and make sure the hose end fittings are steel, not aluminium. I know this may seem futile, when the engine-driven fuel pump and the carburettor are both aluminium, but in point of fact they are much more massive than the fuel line itself, and also they are protected to a degree by the latent heat involved in boiling the fuel out of them. The fire sleeve also serves a secondary purpose, in that it converts a pressurised fuel spray from a split in the hose, to a dribble of fuel from the end of the sleeve. The older grades of hydraulic tube go hard after about six years, so they are a nuisance-value maintenance item. They have largely been superseded by PTFE (Teflon) lined tubes with braided jackets, but although this will resist higher operating temperatures before it goes brittle or melts, it does not survive as long as the older type in a fire, so good fire sleeving is still essential.

 

This is what you find in GA aircraft, though it has taken manufacturers a while to wake up to the fact that the electric pump, gascolator etc should be either under or aft of the wing (where the fuel tanks are) in order to minimise the risk of vapour lock.

 

This standard is difficult to achieve in recreational aircraft, because the carburettor etc are much less massive than in GA aircraft, and they use a simple hose barb for the fuel line connection; but you can still approach the standard by appropriate choice of the fuel line and correct use of fire sleeving.

 

Transport category aircraft no longer use aluminium tube, because it does succunb to vibration unless it is adequately supported; they use stainless steel.

 

 

[jetjr]

The hose supplied from Jabiru was transclecent blue, (now red i think) and for basic flex hose reports well.

 

There is an issue with o rings in fuel taps perishing and allowing tiny amounts of fuel and smell into cockpit

 

Similar to o rings on fuel tanks they should be replace regulalrly I think.

 

Did hear report of these o rings catching in housing and small pieces of rubber being intrduced downstream of filters unless they are used regularly.

 

 

[Dafydd Llewellyn]

The current standard for hoses carrying flammable fluids in an engine compartment, for FAR 23 certificated aircraft, is FAA Technical Standards Order (TSO) C 53 type D

 

C53a.pdf

 

C53a.pdf

 

C53a.pdf

[jetboy]

It does surprise me that plastic hose is used in the fuselage

 

I thought BSA and Triumph invented the stuff to increase their bike sales

 

The Jap bikes and scooters seem to have rubber with outer braid but the usual automotive suppliers seem to have fairly ordinary rubber hose in the past I used Gates SAE30 spec (in my vehicles and 701) but it went hard and lots of cracking so replaced with "Dayco" SAE J30R7 hose - also made in USA which seems more flexible and so far so good. The Gates hoses cracked regardless of Avgas, 95 mogas or Jet-A but never smelled or leaked - I got them out before the cracking had gone past the outer rubber layer. I researched the market and found the "fuel injection" spec hoses are the same rubber and vastly more expensive. For elimination of aromatics seepage there is a version with a different inner layer common in USA but not seen locally

 

 

[Dafydd Llewellyn]

Most motor vehicles of my experience use Bundyweld tube http://en.wikipedia.org/wiki/Bundy_tube from the fuel tank to the engine compartment, and then go to a flexible line. I've used Hypalon-lined hoses in motor vehicles for the flexible lines, and it's been generally satisfactory - before unleaded fuel. Nowadays, I'd use a teflon-lined hose, such as Aeroquip 666 or equivalent.

 

I do not see any good reason to use other than a metallic line up to the firewall; however if you do, it needs to be installed IAW FAA AC 43.13-1. In general, the fuel tube should be some distance below any electrical looms rather than above them.