PDA

View Full Version : Could an exhaust augmenter be used to supplement cooling?



Speedo
03-30-2018, 09:30 AM
This is a question for our resident exhaust system experts:

Is there enough mass flow from an O-320 to O-390 size engine to use an augmenter to increase airflow through an oil cooler, or to increase airflow through the cowling?

I realize an augmenter means added weight (Bill Rusk will shudder), but possibly itís an acceptable trade off.

Iím interested in hearing what the engineers and exhaust system experts have to say.

qsmx440
03-30-2018, 12:38 PM
Look at a Piper Apache. They used to claim it increases cooling and provides additional thrust? Really? I think it was the jet age thing sales gimmick. It definitely makes the O320 sound bigger than it is :-) The weight probably is not worth whatever gain it "may" provide. I do like the cub wing with two engines!

skywagon8a
03-31-2018, 06:20 AM
This is a question for our resident exhaust system experts:

Is there enough mass flow from an O-320 to O-390 size engine to use an augmenter to increase airflow through an oil cooler, or to increase airflow through the cowling?

I realize an augmenter means added weight (Bill Rusk will shudder), but possibly it’s an acceptable trade off.

I’m interested in hearing what the engineers and exhaust system experts have to say.
I'm no expert in this matter though I have been involved in the certification of an airplane which used exhaust augmenters exclusively for cooling. The design does involve some specific dimensions in diameter and length of the tube along with the relationship of the exhaust outlet to the intake of the augmenter. The amount of push from the exhaust determines the amount of cooling air which is drawn through the system. This would be proportional to the amount of power produced by the engine which also determines the amount of heat generated.

Many airplanes have used augmenter systems for cooling with engines as small as the 0-320 on up. Apache, Twin Bonanza, Aero Commander, Helio Courier etc. The augmenter tubes will be 2-3 feet long.


Look at a Piper Apache. They used to claim it increases cooling and provides additional thrust? Really? I think it was the jet age thing sales gimmick.
The Apache preceded the jet age.