Subaru 7A Down

Yukon · #1 06-30-2007, 10:14 PM

Anybody have information on an Egg 7A down in Arizona?

RV7Guy · #2 07-01-2007, 12:42 AM

Hi John,

What did you hear? When, where?

rv8ch · #3 07-01-2007, 03:53 AM

Just picked this off of the Eggenfellner Yahoo group:

Quote:

Originally Posted by Jan Eggenfellner

Off airport landing with a supercharged 4 cylinder. Somehow the MP went to at least 40" and boost warning lights came on. (We will try to find out why) He throttled back and landed but damaged the airplane and engine.

Builder is in good shape but obviously sad.

Jan Eggenfellner

Yukon · #4 07-01-2007, 07:34 AM

Quote:

Originally Posted by RV7Guy

Hi John,

What did you hear? When, where?

Roger Everson, yesterday. He's OK, plane flipped. Supercharged 4 cyl.

RV7Guy · #5 07-01-2007, 08:48 AM

John,

Check your PMs.

rv6ejguy · #6 07-01-2007, 09:13 AM

The Egg STIs have several iterations of the so called wastegate (compressor bleed valve). Some have fitted a cable controlled valve. If you forget to open the valve before closing the throttle, the boost will spike way up because the supercharger is a positive displacement type. Unknown how the stock ECU will deal with this. Typically if it goes way over factory spec, it triggers a momentary fuel cut but shutting off the injectors. There have been several wiring mods to this system and the ECU may not be functioning in the full factory designed mode.

Other engines are using an automatic bleed valve which does not require pilot intervention. This is probably a better idea if it is reliable.

In serious cases, the belt could be thrown if the supercharger sees enough load due to total restriction of the boost air.

gbrasch · #7 07-01-2007, 09:44 AM

Quote:

Originally Posted by rv6ejguy

If you forget to open the valve before closing the throttle, the boost will spike way up because the supercharger is a positive displacement type.

This was not the case in this incident, Roger was taking off under full power, FYI.

videobobk · #8 07-01-2007, 02:09 PM

Met Roger last year at OSH, nice guy. Sure glad he's all right, at least physically at the moment. I believe he had the same carbon fiber canopy I have, so I am very interested in how it stood this ultimate test. Anyone know about that? I know he hasn't been flying the 9A long and has to be devastated.

Bob Kelly

MrNomad · #9 07-01-2007, 03:29 PM

Quote:

Originally Posted by videobobk

Met Roger last year at OSH, nice guy. Sure glad he's all right, at least physically at the moment. I believe he had the same carbon fiber canopy I have, so I am very interested in how it stood this ultimate test. Anyone know about that? I know he hasn't been flying the 7A long and has to be devastated.

Bob Kelly

I spoke to Roger's wife just now and he's ok, plane is wrecked. We visited him several times before we started our 9A project. According to his wife, every morning he was out there flying before work and enjoying the fruits of his labor. Obviously, he is completely bummed out after putting in years of work. His wife said the canopy may have saved his life cause he crawled out from under it suffering only scratches (and a major case of depression I'm sure).

Roger did quality work from what I could see.

rv6ejguy · #10 07-01-2007, 04:19 PM

Quote:

Originally Posted by gbrasch

This was not the case in this incident, Roger was taking off under full power, FYI.

I wasn't commenting on the accident as I didn't know the facts. Merely an observation.

The only way boost can increase on a positive displacement blower system like this at WOT and constant rpm is due to either the throttle closing or the bleed failing to stay in the control position.
Since these engines use a fly by wire throttle controlled by the ECU, several inputs could have the effect of closing the throttle without pilot command.

Very glad that Roger is ok and hope he decides to repair the RV with his wife's blessing.