Another generator question

[hpalmatier]

Is a blast tube for the alternator required?

[n2582d]

Is a blast tube for the alternator required?

First, welcome to the C-170 website and association! Thanks for joining.

I think the answer to your question is a definite maybe. Same answer as our esteemed Blue Leader gives when asked if he wears boxers or briefs: "Depends". You would have to see how your installation was approved. I think most 170's use a Ford alternator with a field approval based on Service Kit SK172-22M. This service kit does call for a blast tube. Other STC's for alternators include STC SA2538NM for a 60 Amp alternator, STC SA00202NY specifically for the "C-145-2 and O-300A", Jasco's STC SA971WE (uses a blast tube), and Plane Power's STC SA10921SC (no blast tube required). You'd have to see what the instructions for each of them call for regarding a blast tube.

[blueldr]

If I was replacing a generator with an alternator, I'd just leave the blast tube there. If tbere was no blast tube, I'd determine if one was necessary for the type of accessory being installed. There was a Cessna alternator and a blast tube on my airplane when I bought it and I never had any reason to question it.
Since the alternator was equipped with a built in cooling fan,I did not install a blast tube when I converted to the TCM IO-360 engine. My own decision. It seemed to work just fine.