What's new
Van's Air Force

Don't miss anything! Register now for full access to the definitive RV support community.

Andair Equipment questions

J

jwilbur

Well Known Member
I'm about to order some fuel system parts and need some help. I'v been through the VAF archives and the questions have been discussed before, but specifics are a few years old. I'm hoping to get some updated opinions.

Specifically,
1... I saw that there may have been a fuel flow issue associated with the Andair fuel filter. Is this actually true or was it just a perception based on physical dimensions (if true, is it still true)? e.g., post #5 here: http://www.vansairforce.com/community/showthread.php?t=108379&highlight=andair

2... And this post indicates some potential issues with O-rings. But it's a few years old. Any further issues since then? http://www.vansairforce.com/community/showthread.php?t=71529

3... What are the pros and cons between the stock system and the Andair fuel pump/filter combo? Seems that the Andair pump/filter combo might be easier to get installed, take up less space, and maybe lighter given so much less tubing. Anything else? Any comments on reliability between the stock setup and Andair?

4... The part numbers I'm seeing for the 10 are PX375-TC and FX375-MK. Is this correct?

Thanks all,
 
Last edited:
The Andair fuel valve and firewall gascolator are essential in my opinion. There is no better choice.

Vans sells the bits you need. Dowloand the price list and do a search for Andair. Order all the bits applicable and note the notes about the T fitting.

The fuel filter is not a flow problem. The O-Ring on the bowl is small and delicate so lubricte it and be careful.

Simple as that.
 
Fuel System

I think it really depends on what fuel system your are planning on using... I started with my injectors and worked backwards all the way to the tanks to build a "system" including the right fuel selector valve (a dual) the right pumps, right filters, right routing of lines etc...
There's a lot of options these days in fuel systems and what it takes to feed them varies on your set up.
 
I was not happy with the dimensions of the filter media on the Andair RV-10 package I received so I replaced the filter with an AFP filter. Nothing scientific but it just looked too small IMHO. If you are going with an IO-540 there is no need for a gascolator.
 
9GT said:
I was not happy with the dimensions of the filter media on the Andair RV-10 package I received so I replaced the filter with an AFP filter. Nothing scientific but it just looked too small IMHO. If you are going with an IO-540 there is no need for a gascolator.
Click to expand...

Yes. I'm going with an IO-540 so no gascolator.

I can appreciate and respect your concern about the dimensions. ... But I'm wondering if anyone has had an actual issue with flow through this filter?
 
jwilbur said:
Yes. I'm going with an IO-540 so no gascolator.

I can appreciate and respect your concern about the dimensions. ... But I'm wondering if anyone has had an actual issue with flow through this filter?
Click to expand...

At 60 hours I noticed a loss of fuel pressure. I removed the AFP filter to service it and was very surprised at the amount of debris and obstruction on the screen. Granted that this was the first filter servicing since I started flying My RV-10 but I am happy I decided to use the larger AFP filter. By visual comparison I "guess-ti-mate" that AFP screen has 3 X the media surface area of the Andair screen that came with my package. I purchased my RV-10 Andair package about 6 years ago so maybe they use a different filter know? Anyway, here are a couple photo's of my RV-10 Andair filter media. I feel much better flying behind the AFP.
DSC00835.jpg

DSC00832.jpg
 
My 20c worth.

I think every engine deserves a gascolator. And if you use the Andair pump system it requires and has gascolators before the fine filter and pump.

If you use the stock Vans pump system from AFP you do not. Look at the different systems and understand why things are the way they are.

If you use the AFP pump and screen, the Andair gascolator is perfect down stream of the screen/pump and before the FCU.

I would not recommend using the Andair pump and filter as a drop in replacement for the AFP pump/screen, without installing a gascolator or two as shown in their schematics.


The devil is in the detail.
 
RV10inOz said:
My 20c worth.

I think every engine deserves a gascolator. And if you use the Andair pump system it requires and has gascolators before the fine filter and pump.
...
I would not recommend using the Andair pump and filter as a drop in replacement for the AFP pump/screen, without installing a gascolator or two as shown in their schematics.
Click to expand...

My understanding is that with an injected engine a gascolator is not needed, that in fact the filter will filter everything the gascolator would filter anyway. If I read things right, in the UK (where Andair is located) there is a regulation requiring a gascolator, which may be why it's in all their schematics (seculation). We don't have that regulation in the US.

Maybe you can explain what the gascolator does that a filter doesn't in an injected engine. I am looking to be educated.

Thanks,
 
Water and any floating debris. Yes I know that should have come out the tank drains, but even if the drains are perfect, can you be sure?

Also I think the Andair pump requires them to catch the bigger bits so the finer filter just has to do its job. The pump in the Andair might also be a higher performing and less tolerant pump.

Maybe someone else has a better answer. I am not a fuel filtration and pumping expert. Between Andair and AFP surely you can get some sound advice.
 
Yes but you need to change 2 filters at the same time.

Is somebody can tell me the lifetime of a fuel filter ? 50 hours or more ?

Sylvain
 
Last edited:
Great choice!

AFP's systems work flawlessly in thousands of installations including some hard core performers like Michael Goulian and many others.
 
RV10inOz said:
Firewall bottom RHS, put a drain extension of 2-3" so you can drain it.
Click to expand...

Correct me, but I thought the best place for gascolator will be located where it will trap water and debris BEFORE it gets to the in-line filter in the tunnel. Draining the gascolator prior to flight will for the most part prevent water and dirt getting to (and clogging) the in-line filter. If I picture your installation correctly, then you have it PAST the filter in the tunnel?
Thanks.
Johan
 
Best Place??

The best place for a gascolator in an injected installation is NOWHERE

Unless your "Guv'ment" requires it.
I think every engine deserves a gascolator.
Click to expand...

Even David should bury that OWT about deserving a gascolator.
It's been debated but keeps creeping up.
Do yourself a favor and forget about the gascolator.
If your are not sure about it call Don Rivera at AFP .
 
Quote

Just found Don's letter to a customer.


Don at Airflow Don at Airflow is offline

Join Date: Jun 2006
Posts: 265
Default Gascolator
This is a letter we wrote to a customer about gascolator use in fuel injected engines.

To fully understand the situation you must first understand why a gascolator was used in the first place. Back when carburetors were the only source of fuel metering on aircraft, water was a detriment to the operation of the engine. Of course water won?t burn but the main reason was that water being heaver than fuel would sink to the bottom of the float bowl. Water also has a higher surface tension than fuel. Since the main jets are located in the bottom of the float bowl and the metering head (the suction created by the venturi to suck the fuel out of the bowl) is low on a carburetor, the water can actually block the flow of fuel through the main jets due to surface tension, thus starving the engine of fuel.

Enter the fuel injection system. There?s no float bowl, the fuel is under pressure (20-30 PSI). So in this case even if there?s some water in the system the fuel control will flow the liquid what ever it is. Granted the engine cannot burn water but there will be no interruption of the delivery of fuel to the engine.

One thing that is in the carburetors favor is that with the float bowl, if any foamy fuel or fuel vapor is in the system, the float bowl will vent off the vapor and the main jets are only exposed to liquid fuel. Correct fuel metering in this case is mostly not effected. Unless the engine driven fuel pump or boost pump is vapor locked the engine will get fuel. In this respect, carburetors are less affected by hot operation. More on that subject later.

Now look at the aircraft fuel system. In an RV aircraft the fuel tanks are the lowest point in the fuel system. Water will be in the sumps of the tanks. If water is found during a sumping operation then further investigation should be made concerning the entire aircraft fuel system condition.

1. Installing a gascolator in any other place other than the wing roots would result in the gascolator being higher than the lowest point in the fuel system. Not the place to catch water.
2. Since the RV aircraft can do some aerobatic maneuvers, rolling the aircraft upside down would dump any water into the fuel system if any were held in the gascolator.
3. Since the fuel injection system does not have a float bowl, fuel vapor is a problem and can cause poor fuel metering. Avgas boils at around 130 degrees F at sea level. The boiling point gets lower as altitude increases and also with a decrease in fuel pressure on the suction side of the fuel pump (flow losses in the fuel system). Since the gascolator is typically installed on the firewall, it is subject to a high heat environment. The volume of fuel in the gascolator does not change very fast at low power therefore the fuel in the gascolator picks up heat, which can lead to fuel vapor issues and possible vapor lock of the engine driven fuel pump.
4. Installation of the gascolator on the fire wall though not recommended on this installation can be accomplished by the following:
a. Make sure the gascolator can withstand 30 PSI, as it will be pressurized when the boost pump is on.
b. Install a blast shield over the gascolator and provide blast air to keep the gascolator cool.
c. Understand that having a volume of fuel on the firewall (gascolator) may result in rough engine operation and poor idle, under hot conditions.
d. With fuel injected installations we want to minimize the volume of fuel in the engine compartment as much as possible. This applies to hose routing and components that increase the volume of fuel that can be heated.


Hope this helps

Don
Click to expand...
 
You must log in or register to reply here.
Back
Top