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Alternator blast tube

D

Dorfie

Well Known Member
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I need advice on how to mount the cold air blast tube to the back of the PP alternator. I installed the 1" pickup for the blast tube in the right side cowl inlet during the build. Cannot figure out a way to attach it well to the back of the alternator.
Thanks.
Johan
 
alternator blast tube

Not needed on the new alternators. I sent email to Plane Power and their reply was, Not Needed. I did put blast tubes on Magnetos.
 
If you have a look at the back of the pp alternator there are two square holes, and behind these holes you will find a heat sink. Apparently this is what you want to be aiming your air at. I've seen examples of elaborate air boxes riveted over these holes with mounts for 3/4 or 1" hoses. As a more simple solution I thought you could also do the safety wire trick like you do on magnetoes, centering the wire between these two square holes and feeding it back up your 1" tube. Alternatively I have found that some of my 5/8 OD ribbed nylon tubing fits nicely in each of these holes (squashed out of round of course) so I am running two short lengths of this into a y connector then up to my baffle, with a small droop and drain hole to deal with any moisture that may enter. Around these round tubes in a square hole I'm sealing with some polyurethane sealant. I'd post some pictures, but my y connector hasn't arrived yet, so I haven't got it completed yet.
Tom.
 
Good to know Steve. It's still called out in my instructions from 3 years ago, however it does seem odd that they would dictate the use of blast tubes on something that they provide no provision for attachment.

Tom.
 
Simple Solution

I used a piece of the ribbed nylon tubing I had leftover. Yes, you want to direct the air to the heat sink, any place else is not effective. Sorry for the rotated picture, TinyPic feels this is the best way to display it. Bank your head to the left 90 degrees and it will look correct.

2uqglxg.jpg
 
Jasonm said:
I used a piece of the ribbed nylon tubing I had leftover. Yes, you want to direct the air to the heat sink, any place else is not effective. Sorry for the rotated picture, TinyPic feels this is the best way to display it. Bank your head to the left 90 degrees and it will look correct.
Click to expand...

I did something similar, but glued a piece of the tubing on at a 90? angle about 2" from the end, then capped the end with a piece of rubber with a small drain hole. This provides an "inertial separator" when flying in rain; the air can make the sharp turn but the liquid water cannot; it gets stuck at the bottom and drains out the supplied hole.
 
tgmillso said:
Good to know Steve. It's still called out in my instructions from 3 years ago, however it does seem odd that they would dictate the use of blast tubes on something that they provide no provision for attachment.

Tom.
Click to expand...

I just received my new Plane Power alternator which was dropped shipped from Plane Power and it came with a bracket with a 90 degree fitting to attach the blast tube. Since I'll be replacing the same model alternator I'll re-attached the existing blast tube.

-Marc
 
Jasonm said:
I used a piece of the ribbed nylon tubing I had leftover. Yes, you want to direct the air to the heat sink, any place else is not effective. Sorry for the rotated picture, TinyPic feels this is the best way to display it. Bank your head to the left 90 degrees and it will look correct.

2uqglxg.jpg
Click to expand...

Jason,
Did you drill a hole in the side of the metal cover at the back of alternator to fit the blast tube?
Thanks.
Johan
 
Dorfie said:
Jason,
Did you drill a hole in the side of the metal cover at the back of alternator to fit the blast tube?
Thanks.
Johan
Click to expand...

I took the metal shroud off and removed (with a dremel) a small piece of metal separating the two square openings effectively creating one larger, rectangular opening. From there just compress the nylon tube a bit and it will fit in there nicely.
 
Plummit said:
I just received my new Plane Power alternator which was dropped shipped from Plane Power and it came with a bracket with a 90 degree fitting to attach the blast tube. Since I'll be replacing the same model alternator I'll re-attached the existing blast tube.

-Marc
Click to expand...

Marc,
I looked at Plane Power website and no mention of the bracket you are referring to. It is somewhat strange that they will send a blast tube attachment if they say none is needed!! You know what size blast tube the bracket will take? Did you by any chance request the blast tube bracket?
Thanks.
Johan
 
Dorfie said:
I looked at Plane Power website and no mention of the bracket you are referring to. It is somewhat strange that they will send a blast tube attachment if they say none is needed!!
Click to expand...

Sure wish someone would attach a thermistor to the regulator heat sink and measure running temperature with and without a blast tube.
 
alternator cooling

I just rechecked PlanePower website. The 70 amp alternator does show a bracket for cooling but the 60 amp alternator does not. Mine is the 60 amp and that's consistent with PlanePower telling me no cooling is needed. Looks like if you need cooling they provide a bracket and that appears to be on the 70 amp unit. You can see drawings for them here:

http://www.planepower.aero/installation instructions.php

have fun
 
I don?t know of any electronics (practically speaking) that don?t live longer if they are kept cooler. Given the proximity to radiated heat from the exhaust, I ran a blast tube. I have a 60 amp, and pointed a blast tube at the heat sink on the back of the alternator.

No real data to support the need however. Perhaps I?ll get some.
 
Dorfie said:
Marc,
I looked at Plane Power website and no mention of the bracket you are referring to. It is somewhat strange that they will send a blast tube attachment if they say none is needed!! You know what size blast tube the bracket will take? Did you by any chance request the blast tube bracket?
Thanks.
Johan
Click to expand...

Looks like about 1" tube, and no, I didn't request it. That's just the way the 70 amp comes.

~Marc
 
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