Fuel fittings

[Lyndon]

Rotax have a complicated two pump set up with non return valves and an extra line with a restrictor. My question is. Do I just go to racetech and buy all the A an N fittings, elbows etc. The whole set up has flared fittings. Airframe mounted so little or no vibration. Or have off the shelf car fittings failed by experience and I need aircraft quality and price.

Thanks Lyndon 

[Thruster88]

I guess this is for the 916iS. Automotive AN from a reputable supplier should be fine. The most important part is that the hose and end connectors are compatible and rated for the pressure. Seek advice if you have not if you have not used that type of hose and connector before. 

 

Do as the rotax install manual says.  

[Lyndon]

Sounds good.

[440032]

Reminder about the difference between aircraft AN fittings and similar looking automotive or industrial fittings.

Aviation are 37 degree angle while generic industrial are 45 degree angle. They are not compatible if you get it wrong.

You can't eyeball which is which and they are difficult to angle measure accurately without some good gear.

Do your research, consult rotax manuals etc. Buy the correct parts, not what you think or hope are the correct parts.

[skippydiesel]

 

Sorry 440032, I am about to "throw a spanner" in your advice.

 

When I was doing my Sonex fuel reticulation (30L wing tanks & central 40L header) all connected by aluminium pipe & AN fittings, I found that to get what I wanted to do the job I had to purchase from both Aircraft AND Automotive AN suppliers, There was never a problem with compatibility , because I made sure I got the correct bits.

 

My suppliers were:

 

https://www.asapspares.com.au/

https://www.aaestore.com.au/

https://aeroflowperformance.com/catalogue-2024

 

Between the three suppliers listed I almost always got the part(s) I wanted, when wanted.

 

Aeroflow have an an amazing range, usually but not always, cheaper than the aircraft parts supply people. Take the time to familiarise yourself with how the catalogue woks, some "stuff" is in categories that you may not at first recognise.

 

If you don't already have the pipe cutting, bending & flaring tools, be sure to shop around - the cheap ones will, with a bit of practise & care, do the job, leave the expensive stuff to the dedicated multi kit builder and professionals.

 

Making consistent well formed flairs, bends without flattening/kinks,  is a skill, take time to practise until you get it right - I found using  a little spray lithium grease helped in most situations and be sure to deburr before flaring.😈

[skippydiesel]

7 hours ago, Lyndon said:

Rotax have a complicated two pump set up with non return valves and an extra line with a restrictor. My question is. Do I just go to racetech and buy all the A an N fittings, elbows etc. The whole set up has flared fittings. Airframe mounted so little or no vibration. Or have off the shelf car fittings failed by experience and I need aircraft quality and price.

Thanks Lyndon 

My system is for a Rotax 912ULS;

 

If you would like, I can send photos of my interpretation of the Rotax boost pump, with non return by-pass circuit  - all a mixture of automotive & aircraft fittings.😈

[Lyndon]

I've got the layout. Just need to buy the fittings. 

Lyndon 

[Thruster88]

On the rotax 912iS and 915iS engines i have seen at work the above twin pumps are inside a rotax stainless enclosure, i thought this was supplied with the engine and you were asking about hose between the pumps and engine?.

[Lyndon]

That's the old style pumps. These new ones don't use rubber hoses and pipe work. Those are not available any more. 

Lyndon 

[facthunter]

Having that many screwed fittings is just ridiculous.. It's like a prototype of something.   Nev

[Lyndon]

In fact you now have 3 layout options to place them in series.To suit your aircraft I presume 

Lyndon 

[Lyndon]

It's that or hose clamps and rubber hose. Eg the older cassette type.

Like I said a complicated system.

Lyndon