![]() |
Alt Air?
Guys --
What's the purpose of the Alt Air control I see on some of the panels .. it's not alt static but something to do with the carb .. trying to figure out why some have it and others don't and is this something that would be needed on the IO-390. Thanks! -- Bill |
These are two separate things. The alternate air is a backup for the air intake into the engine, in the case that the filter gets plugged and engine cant get enough air for some reason.
There is also the alternate static in the case that the static ports get blocked. Both should be incorporated into the build. Hope this helps. |
Ahh, okay, that, and a bit of searching, it makes way more sense now. I've never seen an "Alt Air" port in any of the stuff I've been flying.
(thanks) So much to learn and loving every minute! |
You most likely have been flying airplanes with 'carb heat'. Carb heat not only supplies warm air to the carb, it also bypasses the air filter in case it's clogged.
Most fuel injected engines do not have a heated air option, just a filter bypass called alternate air. If you choose to install a carbureted engine you'll want carb heat instead of ALT air. |
Bob, that brings it home, perfect, thank you.
|
It depends on how you fly. In my VFR plane I have neither Alt Air or Alt Static Air.
If I were to add IFR capability to my plane, you can bet I would add both. |
Quote:
|
Quote:
Chris |
Quote:
|
Is it opinion to have the alt air intake in addition to carb heat or recommendation? My understanding was it was a choice and not really needed if carb heat is installed. It isn't a difficult thing to add, not nearly as tricky as the carb heat.
I did not plan to have the alt air. Should I? |
Quote:
I'm just thankful you didn't not mention having a bird go in the intake. If you are worried about that, then you should cover the canopy with a fence of some type because there is a better chance of taking a bird through the windscreen than in the air intake. |
Quote:
|
Quote:
As an EAB airplane you are of course free to do what you please. But given how relatively easy and inexpensive Vans' alternate air design is, it seems penny wise but pound foolish not to install it. |
Quote:
|
The question.
If I were to be building with the installation of an IO-XXX "take your choice", I would as I have done, install Alt. air for the engine. We have it on our bird for all the good reasons that a Part 23 spam can dose. Just my two cents on the question. Yours, R.E.A. III #80888
|
Quote:
|
Quote:
|
Quote:
I did replace the almost useless juice can heat muff for this from Wicks and actually see a noticeable RPM drop now. It really comes down to your risk tolerance. Ask yourself this, "What are the odds of an intake blockage?" If you don't like your answer, install it |
This is the exhaust system I have and the heat muff. I do not think it is the best option for exhaust or how the FAB fits to the exhaust. I would not do it this way again.
https://www.vansaircraft.com/pdf/rev...ther/OP-54.pdf I believe the carb heat I installed is acceptable risk for me and will not be installing the alt air. |
Video
Here is a video of my alt air door in action. This is looking up at the bottom of the filtered air box, controlled from cable in cockpit. https://youtu.be/YhsEx4_Z9v0
|
| All times are GMT -6. The time now is 01:53 AM. |