Silicone Oil Hoses?

Hi Sean

An experimental can use garden hose if he so wishes.  This however does not suggest that is a good idea.  Best practice is to follow the requirements for certified aircraft that have standards.  The FAA sets the standards for certified aircraft and for aircraft in the Special Light Sport class the standards are under the ASTM F37 industry standards for this class of aircraft.  

I know that you argue a lot about not following such standards and for your aircraft and as an experimental thats just fine.  Everyone should look at what his airworthiness requirements are based on where he flys and the regulations, if any, he must comply with.  I know that many inspectors, even when signing off an experimental in the USA, will not say the aircraft is airworthy unless it meets at least some basic safety rules.  If you can sign off your own aircraft then you are golden and can do what you want.  I know Roger and am pretty sure he would not sign off on an engine if there was any perceived risks.  

So back to the original question, the answer is no, do not use silicone hoses for fuel or oil as they are not compatible at a molecular level.  They will likely fail.  While very good with coolants I would never recommend them as an oil line. 

Check it out online, there are lots of hose suppliers and the answer the same. 

Cheers

I fully agree with RW. I don't use aftermarket parts and it doesn't leave my shop with below average work. Plus silicone and Teflon hoses are quite expensive. I know a few who did install Teflon hoses for their` oil and fuel and it was around $2400.

Like RW stated. I would HIGHLY recommend everyone put fuel and oil hoses in fire sleeve. I'm a retired 30 year firefighter and can tell you exactly what happens in the engine area with a fire and especially when it ignites the fuel and oil.

Hi RW,

This all said I just did a search and there are a couple of companies that sell silicone hose for fuel and oil. I was a little surprised and some were okay with the FAA.

Aircraft Specialty uses Teflon. 

Liability and injury,  neither are worth the risk.

Hey Roger

Teflon inner liners are fine, the issue is silicone hoses are not good with any type of solvents.  Most oil lines would need to have an inner sleeve to protect them if used with oil.  Silicone outer on a fuel line may work but it would need a liner for sure. 

There are some special hoses with "fluorocarbon and fluorosilicone liners, this may be where the confusion comes from.

Cheers

https://www.siliconehose.com/blog/oil-fuel-and-silicone-hoses-/?srsltid=AfmBOoqR8TXM8Of7uBc7IW4_Uc98fgrNKtxG8Dd_IU8HGcGIXuA9oQAR

Great! - just lost my entire response to RW - another 15 minute's wasted.

Happy New Year RW,

“An experimental can use garden hose if he so wishes.”

You should be a politician – this is a slight by inference. I have never suggested using any parts that are below Rotax standards. Further, I prefaced/follow, all suggestions, for non Rotax parts, with something to the effect of “…experimental / home-built aircraft…..”

“Best practice is to follow the requirements for certified aircraft that have standards.”

Thousands of Rotax engines, flying safely/reliably, in most parts of the World, using press/slide on fuel / oil / coolant hose fittings – Is this tried & true hose attachment system, as per “… certified aircraft…. standard”?

As far as I know all Rotax use automotive style, metric screws/nuts/bolts – not certified (Mil-Spec?).

Facet Fuel Pumps are almost ubiquitous in Rotax and other small aircraft applications (both experimental & factory builds). Facet go to the trouble of stating on their web page Not for Aircraft Application.

I am sure there are many other examples of rational substitutions, that have stood the test of time.

The standards are already being challenged, not just by experimental home builders, also by factory builders.

Boggy man statements, will work on those unwilling or unable to research alternative parts supply, fortunately there are others who are able to make up their own minds

“I know that you argue a lot about not following such standards and for your aircraft and as an experimental thats just fine.” 

Point of order: I have never suggested “not following such standards” In fact I repeatedly use the phrase “must meet Rotax standard or better”

“Everyone should look at what his airworthiness requirements are based on where he flys and the regulations, if any, he must comply with.”

Agreed 100%

My position on aftermarket (non Rotax supplied) parts is, as always – must meet Rotax standards or better.

To this end I have found Gates oil, coolant & fuel hose, that do just this, at a fraction of the OM cost.

In the past, I purchased a Ducati radiator cap, from a motorcycle shop, with the same part number & specifications, as supplied by Rotax, at about 1/3 of the price.

I have used small, road legal (good to 120 kph) tyres & tubes.

I purchase my coolant concentrate, constant tension & fuel injection hose clamps, from auto supply shops.

Fuel (98RON) comes from my local auto fuel station.

My Rotax/Ducati VR, failed at about 150 hrs, despite a dedicated cold air tube. Replaced by CARMO, CARR 5115, MOSFIT – so far (193 hrs) so good.

Certified Guardian Avionics panel power ($249 + US) failed @ 175 hrs. Replaced with TREKLO 12 Volt in, 5 Volt out, Dual USB-C 100W (20 amp) & USB-A 36W (7.2 amp) about $16 US. Delivers as expected.

My maintenance regime is as per the book; except I choose to do 50 hr oil changes.

I use Rotax specified & where appropriate, supplied, AeroShell Sport Plus 4, Rotax oil filter, all replacement parts for engine e.g. 5-year rubber replacement carburettor part.

As for Fire Sleeve – good idea for helping to keep fuel cool, hoses from being heat effected by exhaust pipe proximity, bit of abrasion protection. When it comes to fire resistance, unless sleeve is terminated as per specification (most are not) then it’s just a feel-good exercise. Then you have to consider all those Rotax installations, that have little or no fire sleeve – not too many making fiery descents.

😈

Rotax Wizard wrote:

Hey Roger

Teflon inner liners are fine, the issue is silicone hoses are not good with any type of solvents.  Most oil lines would need to have an inner sleeve to protect them if used with oil.  Silicone outer on a fuel line may work but it would need a liner for sure. 

There are some special hoses with "fluorocarbon and fluorosilicone liners, this may be where the confusion comes from.

Cheers

https://www.siliconehose.com/blog/oil-fuel-and-silicone-hoses-/?srsltid=AfmBOoqR8TXM8Of7uBc7IW4_Uc98fgrNKtxG8Dd_IU8HGcGIXuA9oQAR

Hi RW,

 I fully agree with you. Just posted some of the things I found. I didn't mean to sound controversial. 

Teflon would be the way to go if you wanted away from rubber hose. It's just so dang expensive. It's so much cheaper and isn't any big deal to change.