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-   -   5 year hose replacment (https://vansairforce.net/community/showthread.php?t=126907)

edward7048 06-22-2015 06:29 AM

5 year hose replacment
 
Does the 5 year hose replacement start at the year of manufacture
or the year the engine was put into service? What hose are to be
replaced?

Kent Ashton 06-22-2015 06:48 AM

Quote:

Originally Posted by edward7048 (Post 992751)
Does the 5 year hose replacement start at the year of manufacture
or the year the engine was put into service?

I just replaced a rubber (Aeroquip 303) hose to the oil cooler that was 14 years old. The rubber had gotten harder than new hose but it was in good condition and probably would have lasted a lot longer. There is no particular limit on an Experimental. 5 years seems a little conservative to me.

Mel 06-22-2015 07:06 AM

There is a 5 year hose replacement requirement for SLSA.
For ELSA it is a recommendation.
Rotax recommends 5 year replacement on their engines.

cactusman 06-22-2015 08:50 AM

Later engines with teflon hoses had the 5 year fuel hose replacement cx.

see: http://legacy.rotaxowner.com/si_tb_i...si-912-022.pdf

Of course then there are other rubber hoses. I would think a good condition inspection would assess these each year (i.e. coolant hoses, etc)

In AZ we replace batteries and tires every 2-3 years like clockwork.

3 summers and done usually.

RFSchaller 06-22-2015 09:08 PM

John,

I agree, but it's tough to assess a hose under fire wrap. I bought the Teflon fuel hose package from Aircraft Specialtyand will install it at next annual in March. I am dreading the oil and coolant hose replacement in 2017. I think I'll look for a premium automotive heater hose for the coolant lines. I think the lines are 5/8" except for the radiator hoses. The spring in the radiator hose to prevent collapse seems overkill. I would like to hear some operating experience on that. I have seen some coolant hoses in automotive applications that are extremely flexible and do not kink.

Rich

Sink 06-22-2015 09:59 PM

I'm a big believer in the 5 year hose change because you can't pull over to the curb, you don't have X-Ray vision to look under fire sleeve every annual, you can't see the interior of the hose where the clamp is to see the liner of the hose cut, you can't tell if the clamp was applied to tight, you can't tell if a hose is good or bad by squeezing as some think. If the hose is hard you're way past replacement time. You can't see Ozone that damages hose and hours on a hose isn't the only thing that causes damage. I have seen countless hoses that were damaged that the owner or a mechanic thought and swore were good, not to mention the off field landings caused by a bad hose.
Gates did a hose report years ago and found at 3 years you had a few failures, but starting at 4 years the hose incident rate shot up and the more years that it went on the worse it got.


Rotax changed the replacement on the red Teflon hose that feeds the carbs to on condition.





Here is a kicker. The FAA legal ruled a few years back that Rotax or an aircraft company can not put any rules in place more restrictive or on the other hand give away the farm over what the FAA already has in place.
I'm a big believer in the hose change, but legally Rotax can not make it legally binding. This particular rule has been discussed on several forums.

Sink 06-22-2015 10:18 PM

The RV12 is a fairly easy plane to do the hose change on. One person should be able to do the entire Rotax hose change with all its components in a day on an RV12. The fire sleeve can be re-used.

Generally speaking;
Many people seem to use the Gates Barricade hose because of its top rating for ethanol and low vapor seepage. You don't need the high pressure fuel injection hose, but can use the carburetor rated hose. It has a tad more stretch and goes over fittings easier with less chance of shearing off the inner liner and causing debris. The top coolant hose and the two bottom side hoses on each side are 17MM and there is no US equivalent and it is made by only one company for Rotax. The other large coolant hose is 25mm or 1" and many seem to use either Dayco or Gates Green Stripe hose. There is also a Rotax coolant hose that has a 90 degree bend.
The biggest issues is to get people to use proper hose clamps and not to apply too much clamp pressure. Don't use garden hose style clamps on fuel line. The next thing is not causing hose debris which comes from the wrong type hose cutter, forcing hose over a fitting, wrong type clamps, too much clamp pressure and failing to blow the hose out before you put it on the fitting. Pushing hose through fire sleeve can get debris in the hose so it needs to be blown out. Don't forget the rubber carb sockets, the carb diaphragms, the 66mm carb balance tube rubber hose. Some people do use springs in some hoses to keep the radius fully open on tight bends. This would depend on the aircraft MFG and engine installation. When a hose gets a reduced radius it slows the flow of oil or coolant and causes high temps.

p.s.
Hose debris isn't caused by the hose unless it was a bad batch from the MFG. which is rare it is caused by poor installation procedures.

TS Flightlines 06-23-2015 05:20 AM

The reason we use Teflon hose is because the liner is impervious to most all chemicals in fuels, oils, hydraulic fluids, etc. I personally dont know all the chemical makeup of the fuels that you guys use. We do know (from another aircraft manufacturer) that 'some' hoses they were using would begin to fail after a period of time with mo gas. Time frame started about 3 years. I dont know the flight hours. BUT---dark deposits of the liner were getting into the carbs, creating a 'mess'. Inspecting the hoses found the there were crack, and small pieces of the liner missing. (Think of a mud puddle after it drys and begins to crack and shrink.)

Teflon eliminates this issue. Rotax is using Stratoflex 101 hose for the carb hoses OE on the 912 engines. The other fuel hoses were supplied by the airframe manufacturers. Aircraft Specialty and TS Flightlines spent alot of time working on a replacement package that was reliable, and did not have to undergo the 5 year replacement recommendation. Yes its is more expensive and more involved then your gas hose from auto parts store with hose clamps, but after seeing some of the hose failures that we saw, teflon was our choice.
Tom

powerm 10-20-2019 06:25 PM

RV-12 Prebuy Question
 
I?m looking at purchasing a 2014 SLSA. It just completed annual. I asked about the 5 year rubber hose replacement ?requirement?. I was told the hoses were in excellent shape, aircraft quality, and it would be ?pointless? to replace them.

I?m new to RVs, and would appreciate any feedback. Thanks

Mel 10-20-2019 06:42 PM

Quote:

Originally Posted by powerm (Post 1380987)
I?m looking at purchasing a 2014 SLSA. It just completed annual. I asked about the 5 year rubber hose replacement ?requirement?. I was told the hoses were in excellent shape, aircraft quality, and it would be ?pointless? to replace them.
I?m new to RVs, and would appreciate any feedback. Thanks

Rotax may not "require" a 5 year replacement. However the SLSA manufacturer "can" "require" the 5 year replacement based on Rotax's recommendation.


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