Silicone hoses - are they OK to use?

[skippydiesel]

30 minutes ago, facthunter said:

In my view with aircraft which can't rectify things in the air it's better to be cautious. Why risk it? If you are always getting some residual high pressure you must be getting some escape of high pressure gas, (porosity or gasket seepage) or the engine is above a temp where the coolant boils at Zero pressure differential.. Nev

There is certainly no additional risk in my aircraft application - I can not speak for the long coolant hose runs found on some gyro's but I suspect they will be the same and the need for heavy ribbed/stiff/internal coils  radiator bottom hose, is redundant.. 

 

As for "If you are always getting some residual high pressure you must be getting some escape of high pressure gas, (porosity or gasket seepage) or the engine is above a temp where the coolant boils"  - Come on Nev! I didn't come down in the last shower - if you have a vehicle/engine with a recovery/overflow reservoir,  I respectfully suggest you go out and open the radiator cap (only at ambient temp) - if there is a small spurt of coolant - that's a little positive pressure in my book. All my vehicles /machinery does this and they are all in excellent working order.

[facthunter]

One day we may agree but it's unlikely.  I doubt you are up to it. Why not take the safer option. What harm is done?. You argument "I've been doing it for X years" and no problems" is not enough.. Nev

[skippydiesel]

Thanks Nev your condescending tone/language is positively inspiring - I just know that must be pretty much on the right track. Logic experience and  evidence is on my side - come on board you may find it enlightening.

[Blueadventures]

On 26/11/2020 at 9:44 PM, ozzietriker said:

Hi All,

 

I'd love to hear anyones experience and any feedback good or bad regarding silicone hoses used on Rotax 912ULS engine and whether if this is appropriate? I recently completed a Rotax 5 year rubber replacement on my engine and replaced the one inch stiff ribbed style hose with a silicone one inch heater hose. This silicone hose flex (refer to pictures) easily meets/exceeds the temperature and pressure requirements of this system and there are no kinks when hot or cold. 

 

I would love to hear anyones opinions/feedback on whether if this was a good idea or not.

 

Thanks in advance!

Andrew

Is the oil canister mounted as per Rotax installation manuals as it looks low in the image. Just asking for my curiosity if they are normally mounted low in you aircraft type.  Also I have been using silicone hose for about 2 years now all good, I use adjustable hose clamps, the type that pull up over themselves as the type that don’t slide over themselves will tear the out layer causing damage. Also use the 4 ply type not the two ply type. You see the number of ply’s through the end on view.

[skippydiesel]

 

"Is the oil canister mounted as per Rotax installation manuals as it looks low in the image"

 

Blue - with my very recent experience I was too afraid to mention this --- but I had the same thought. I am sure there is a Rotax 9 specification for the position of the oil  reservoir/canister relative to the engine - I am sure some knowlegiable person out there will confirm this and what the spec is.

 

I am a big supporter of Gates parts (hoses, belts/etc). I find that in most cases they have comprehensive data on their products eg working pressure limits, permiability, compatibility, etc. This allows the user to make rational selections without having to be ultra conservative eg over-specifying, which usually means additional weight & cost, to no practical advantage other than emotional piece of mind.

[Blueadventures]

Just now, skippydiesel said:

 

"Is the oil canister mounted as per Rotax installation manuals as it looks low in the image"

 

Blue - with my very recent experience I was too afraid to mention this --- but I had the same thought. I am sure there is a Rotax 9 specification for the position of the oil  reservoir/canister relative to the engine - I am sure some knowlegiable person out there will confirm this and what the spec is.

 

I am a big supporter of Gates parts (hoses, belts/etc). I find that in most cases they have comprehensive data on their products eg working pressure limits, permiability, compatibility, etc. This allows the user to make rational selections without having to be ultra conservative eg over-specifying, which usually means additional weight & cost, to no practical advantage other than emotional piece of mind.

Usual specification is reference point being mid section on dip stick, mid way between the low and high fill, l flat maker and a 'y' axis through the prop flange centre and position not more than 400mm below the 'y'.  Will be in the install manual.