Monthly Archives: July 2016

Engine Fuel Filters-Part One

Van’s instructions call for one fuel filter mounted on the port gear tower. Like other builders, I elected to mount two fuel filters, one at each wing root. I like the idea of having them outside the cockpit and expect that it will make inspection easier and cleaner. Only time and experience will tell!

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Update: I had to relocate the fuel filters when I mounted the wing. Click here for more info.

Engine Control Cables

Another unintended consequence of making a non-standard intake manifold and fuel injector choice was that Van’s throttle and mixture bracket won’t work. You are then on your own.

I had a few guiding objectives for fabricating the throttle and mixture bracket:

1. The control cables needed to be routed as far away from the hot exhaust pipe as possible. This meant that they had to be routed above the intake tubes. Van’s control cables are really intended for boats and not intended for the hot and harsh aircraft engine environment, so staying away from the heat was important. Heat shields and reflective heat tape were used liberally to address this:

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2. I did not want to create any sort of “bulge” in the lower cowl to accommodate the fuel injector control levers, so that meant they had to be operated as vertically as possible. Different techniques were used to accomplish this. The throttle was the easiest as an aluminum angle arm was used to reverse the throw and orient the action up high and outboard, so as to miss any potential for chafing and interference with the intake induction tubes:

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The mixture utilizes 1/8″ thick 6061T6 aluminum angle to create a 90 degree control connection.

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Both controls operate smoothly with no binding, no chafing and operate to the full extent of their throw. All elements are safetied appropriately.

Engine Air Induction

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A warning to those that contemplate going “off the reservation” when making non-standard engine and fuel injection choices: without knowing it, you are probably adding 1-2 months of building to your schedule as you fabricate custom cable brackets, finesse clearance issues, and generally re-invent the wheel to make those choices work.

My engine order included a 7 degree up-tilted ECI intake manifold and an Airflow Performance FM200A injector. These choices meant (although I didn’t know it at the time) that the standard Van’s throttle and mixture brackets would not work, that the standard Van’s induction would not work and that I would have to fit a ram air scoop to the lower cowl.

The Airflow Performance FM200A injector is a wonderful piece of machinery, but it is very long in comparison to the Bendix/Precision Silverhawk injector which is normally furnished. I chose this injector because I believe(d) that it will add performance. After spending two months and a lot of money to figure out a way to make it fit in the cowl, I’m not sure it was worth it.

In the end, I fitted a Spectre 9833 Inline Air Box to the injector using three AN525 washer head screws (#8) with lock nuts mounted to the outside for easy inspection. The inline air box is constructed of .063 aluminum with a cone filter mounting inside. The halves of the air box are held together with a wide stainless steel clamp. The air box installation is very secure with nothing in the air path that could come loose and enter the engine. The filter (HPR9833) is rated at 450 CFM, so that ought to be more than adequate for this engine, even expecting less than optimum air flow. I mated the air box to one of Rod Bowers’ scoops, so it’s a straight shot directly into the injector.

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This air box setup did not allow for alternate air, but I had decided not to install that anyway. The decision of whether or not to include alternate air on experimental aircraft is, like many others, almost religious. Some swear you need it in case of the plastic bag blowing across the runway on take off and others are firmly of the belief it’s more trouble than it’s worth. I tend to belong to the latter camp and after flying for more than 35 years, I’ve yet to have a case where it was needed. It is not required, and therefore I elected to not install it.

Engine Photos

While I will make comments about individual features of my engine and FWF installation, I am including a gallery of views of the engine here. It’s a Titan IOX-370 dynoed at about 190 HP.