Use for Spare Air Blast Tube?

by David HEAL in 912 / 914 Technical Questions 10 years ago

I just relocated the regulator/rectifier on my RV-12 from the hot firewall area to a cooler area inside the cabin. The former firewall installation included a now unused one-inch air blast tube with shroud that served to cool the regulator/rectifier. Rather than removing the now unused tube, could I usefully repurpose it to provide some cool blast air on another heat-sensitive part of my 912ULS? Perhaps the rear of the alternator/generator unit? The ignition modules on the top of the engine? Usually I would blast the fuel strainer area to decrease vapor forming tendencies, but the strainer is too far away.

Any thoughts? Thanks -- David

ps - It is rather startling as how hot the regulator/rectifier gets during normal operation. I can not touch it for more than 5-10 seconds!

Re: Use for Spare Air Blast Tube?

by Roger Lee » 10 years ago

Roger Lee

131 5.38k 5.44k

Hi David,

Your right that a reg/rec should not be so hot that you can't place a hand on it. The hand should be okay for temps around 145F. I do recommend before you try doing lots of things because of high temps that you check to see what those temps really are. My reg/rec is mounted on the firewall down low and I have temp indicating strips on it and the ignition modules. I have never seen an reg/rec temp over 140F and never over 150F on the ignition modules on top the engine.

Engine temp is not the only thing that makes heat in the reg/rec. It could be a sign of an electrical issue that hasn't fully reared its ugly head.

Purchase some temps strips and put them on any parts you want to check the temp on. They usually come in a 10 pack.

You have to be careful with changing air flow in what we think are positive flows. You would be absolutely shocked to see what minor changes under the cowl does to air flow and many times it isn't what we think and it disrupts the air flow with negative affects.

Roger Lee
LSRM-A & Rotax Instructor & Rotax IRC
Tucson, AZ Ryan Airfield (KRYN)
520-349-7056 Cell

Report

You do not have permissions to reply to this topic.

Title	Category	Replies
Ram air to Bing carbs	912 / 914 Technical Questions	7
ROTAX Service Instruction: Introduction of Sodium-Filled Exhaust Valves and New Cylinder Heads for ROTAX® Aircraft Engine Types 912 and 912 i (Series)	General Tech Discussion	9
XPS oil at Aircraft Spruce	General Tech Discussion	1
Airbox to Carb Duct	General Tech Discussion	5
Mandatory Service Bulletin: Inspection and/or replacement of expansion tank assy. for ROTAX® 912, 914, 912 i, 915 i and 916 i (Series) Aircraft Engines	General Tech Discussion	30