Alternate Air Supply For Fuel Injection

[Backpacker]

Is there a thread for how people have made a alternate air intake source for fuel injection as its a required item for final inspection in Canada.

[Dave S]

Ken,

A good idea to identify the type of engine you are talking about because the answers will likely be different.

FYI - if you have the Rotax fuel injected engine, I believe Rotax MAY have an induction airbox designed for their FI engine which provides a bowden cable controlled alternate air option under the cowl. Worth a check with a rotax dealer.

[Backpacker]

Ken,

A good idea to identify the type of engine you are talking about because the answers will likely be different.

FYI - if you have the Rotax fuel injected engine, I believe Rotax MAY have an induction airbox designed for their FI engine which provides a bowden cable controlled alternate air option under the cowl. Worth a check with a rotax dealer.

I have the Rotax Edge EP912 STI with fuel injection and turbo. A friend sent me a pic of a air filter that looks like K&N with the end that is normally closed and flat having a butterfly valve that can be opened for emergency alternate air intake. I can add the pic later but its from Revmaster Aviation in Hesperia California. Its something that would work, just might have to attach to turbo inlet with a 90 because of cowling room. Is this needed in USA to pass inspection...it is a requirement in Canada to pass inspection.

[Dave S]

Ken,

There is no blanket requirement for alternate air in the US for experimentals. That is left up to the manufacturer, meaning the builder.

Agreed, your biggest challenge might be room under the cowl and the need to design a one off alt air for the Edge modifications.

[Backpacker]

Pics from Revmaster aviation

[dothedr3w]

Let's revive another old thread. Has anyone else rigged an alternate air in their Kitfox? I'll be using the same engine as backpacker, and I'm also located in Canada, so this is another thing I've got to look into.

[patrick.hvac]

Anyone doing a fuel injected build has to deal with this, in Canada. No it is not a requirement in the US.
Where is your air intake and filter for the turbo coming from?
You can always get away with an emergency trap door filter bypass. The Alt Air doesn't need to be on/off functional.

[Backpacker]

Anyone doing a fuel injected build has to deal with this, in Canada. No it is not a requirement in the US.
Where is your air intake and filter for the turbo coming from?
You can always get away with an emergency trap door filter bypass. The Alt Air doesn't need to be on/off functional.

Yes on my Just Aircraft SuperStol I installed bypass slide door that I purchased from Vans, which I installed on the rubber end of the K & N filter. My K&N filter is installed directly to the turbo. I had a 2 piece aluminum housing built that goes over the K&N filter, this housing has a round nipple that I attach scat hose to, then the opposite end of that scat is connected to the inside nose of my bottom cowl. I attached an aluminum flange for the scat to attach to on the inside of cowling. When I park a tennis ball fits perfectly into the air inlet on outside of cowl. I have orange parachute cord attached to the tennis ball and loop it over my control stick in cockpit so I don?t ever forget to remove the tennis ball.