bret

bret

Well Known Member
Just had a thought outside of the box. I have seen a lot of Alt failure threads here. Just throwing it out here for peps to slam me here I go... My 2001 Dodge ram has the 140 Amp Alt. 250,000 miles and no failure. Thought one, Idle RPM 850 and full charge, max RPM is 3200. The 5.9 Cummins is a lot like the Lycoming engine, low RPM and lots of vibration. Sometimes we have to get out of the aircraft mind and look at the millions of dollars that go into the auto industry's R&D Pond of thought......(How much does a recall cost us for 2,000,000 vehicles to come back for a stupid alternator? )
Side note, I am running the 450 watt, 28 V. landing lights in the Buckstop Winch bumper using a 3rd Batt and relays. (35 AMPs) Trailer batt and EOH brakes, big music amps and stupid stuff. This Alt has been abused, taxed and lives, what thoughts have you my firends......
 
I wonder how much it weighs (amps = more copper) and how big the cutout in the cowl would have to be to make it fit :eek:
 
If you really need 140 amps, then fine. However, airplanes are all about "just" meeting requirements - anything above the requirement simply adds weight.
 
Toobuilder said:
If you really need 140 amps, then fine. However, airplanes are all about "just" meeting requirements - anything above the requirement simply adds weight.
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Not to mention the engine power required to produce 140 amps..........if you really needed it.
 
Hmm

This sounds like the more= better argument. Which has SOME validity. I mean how much longer will diodes and regulators last if they are doing a fraction of the work they are rated for?

But like others have said, such an alternator would weight a lot and there is no reason you can't make a bulletproof 60A alternator in any case.

The other point is that alternators are spun REALLY fast on Lycs due to the size of the big pulley..like almost 10" diameter.

So even though the engine itself is turning slowly, the alternator is not, so lots of charge can be gotten at pretty low engine RPMs.

Frank
 
Weight? really, this thing is 5" deep and 5 1/2" dia. Pulleys and mounting are a no brainer, I was just thinking of the reliability, and the load on the pulley would be proportional to amp draw.
 
sorry for the big pic, but here it is, 10 years old and 250K miles.


DSC02682.jpg
 
Besides the weight and unique vibration there is also a lot of heat. Could bake those built-in electronics much faster then by liquid cooled diesel.
 
Ratings can be misleading though. I once had a car, believe it was an early Saturn, in doing the research I found that to obtain the "rated" output amps, you would have to be travelling 130 mph in -30 degree weather, I never tested it.
 
Your photo does not match what AllData tells me

bret said:
sorry for the big pic, but here it is, 10 years old and 250K miles.


DSC02682.jpg
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Brett,
How about some more details about your truck. I had to guess, since there are many variants of that truck, and two variants of your engine. AllData [professional auto mechanic computer based info] tells me that your truck should have a 136 amp BOSCH alternator [big and heavy] However, the photo you provide above shows a "big" Nippon Denso [60 to 140 amps] alternator.
FYI, the 'big" ND alternators are EXTREMELY reliable. They weigh about 2 pounds to 3.5 pounds [depending on amp rating] more than the "small" [30 to 60 amp] ND alternators.
FYI, the alternator pulley on your truck is about 2.5 to 2.75" in diameter. For aircraft use, install an aluminum 4" pulley for a Vee belt [15mm shaft size] These are available at most automotive "hot rod" shops.
A 60 to 80 amp version of your alternator should provide more than enough power [with reserve] to take care of ANY RV electrical system.
Charlie
 
OK OK, I did not expect this to get all technical and stuff, back out to the truck and pull the build sheet, you are right, it is ONLY a 117 amp alt. sorry for all the confusion. But, I think I will be trying this combo when I get there. Tested reliability is what I am going with. $100.79 compared to.......
 
bret said:
Tested reliability is what I am going with. $100.79 compared to.......
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I don't really think the fact that it works well in your truck automatically qualifies it for aircraft use.

If that was the case, then we would all be running Honda engines in our aircraft :D
 
Now Walt, you are just saying that because it is true!

Walt said:
I don't really think the fact that it works well in your truck automatically qualifies it for aircraft use.

If that was the case, then we would all be running Honda engines in our aircraft :D
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A Honda ENGINE? how about a Subaru? this is not a auto VS aviation engine war, just a spinning piece of copper. If we take this alt example, it has been going strong for over 5,000 Hr. OK, now go to bed, Santa is coming.
 
I had an aviation alternator go bad on my Cherokee 140 years ago, looked like the one on a junked Plymouth Valiant I had out back. Pulled it off and put it on the Cherokee and many years later, it was STILL going strong!

bret said:
A Honda ENGINE? how about a Subaru? this is not a auto VS aviation engine war, just a spinning piece of copper. If we take this alt example, it has been going strong for over 5,000 Hr. OK, now go to bed, Santa is coming.
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...And I have a "junkyard" ND alternator on my airplane that I used as a fabrication mock up... It's still going strong after 5 years...

This begs the question: Are alternators so unreliable that we need to seek out new sources? I certainly don't think so. There are hundreds of different alternators that would work just fine - not sure there's any value in picking one that's way oversize simply because it has gone 200,000+ on a truck.

It's an alternator... Pick one that meets your requirements and go fly.
 
I think the intent of the thread was that we don't have to have some company redesign, and manufacture an alternator with low production figures, stamp "aviation" on it and jack up the price to unaffordability, when we have a great choice of automotive alternators with millions in service with proven long life, quite affordable and readily available, not necessarily to use an old Dodge truck alternator.
 
These are RV's... I think ony a few of them are equipped with "aviation" alternators to begin with.

...Doesn't Van supply the "car" alternators in his FWF kits?
 
My own casual observation (no data to support this) but it seems like at flyins, experiences with friends, and talking to owners who've had issues (like the ones here) the "aviation" alternators are less reliable. There have only been a few instances in my experience of Autozone alternators going bad. That said on the way to Oshkosh one year a friend of mine had to stop on the west side of Chicago with a dead alternator. Long story short a trip a few blocks away to Autozone saved the day. There is a huge amount of value in being able to locally source something like an alternator if/when they do quit. Had it been a PP or a B&C the airplane would have been there a week or more.
 
So, how would you evaluate and judge the quality of an automotive alternator? Particular technology or mount style that make it compatible and reliable?
 
I use numbers, there were 2.5 million Honda Fits sold as of 18 months ago, no reported alternator failures issues.
 
rocketbob said:
My own casual observation (no data to support this) but it seems like at flyins, experiences with friends, and talking to owners who've had issues (like the ones here) the "aviation" alternators are less reliable. There have only been a few instances in my experience of Autozone alternators going bad. That said on the way to Oshkosh one year a friend of mine had to stop on the west side of Chicago with a dead alternator. Long story short a trip a few blocks away to Autozone saved the day. There is a huge amount of value in being able to locally source something like an alternator if/when they do quit. Had it been a PP or a B&C the airplane would have been there a week or more.
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I concur. Any alternator can fail, but anecdotal evidence I've seen/heard from bouncing around the RV community for nearly 15 years indicates the "Autozone" alternators (and regulators when needed) are a very reasonable option for our applications for the reasons stated above. Proponents of PP and B&C have been vocal about the superiority of those units but a multitude of RVs have flown for years with automotive alternators. The Geo Metro/Suzuki 60A alternator seems to be an excellent option for those who need more grunt than the 35A Honda alternator can provide. And the lifetime, anywhere warranty certainly is nice.
 
For critical items I use a simple formula:

1) How many are flying
2) How many years have they been flying
3) How many hours accumulated, flying
4) How many reported failures
5) Does it have good support.

Only when I am satisfied with all of the above will I install it on my aircraft (or someone elses).
Perhaps I am a bit more conservative than many of the folks here but I don't like surprises when I'm flying.
 
Temperature

Seems this is the one key potential difference between the automotive install and a tightly cowled Lycoming.

Has anyone measured the ambient temperaure inside the cowl at the alternator location and compared that with the average car with a tiny engine bay?

Frank
 
Another data point. I have had a variety of B&C products in various aircraft over the years and have never had a failure of any kind. YMMV
 
flickroll said:
Another data point. I have had a variety of B&C products in various aircraft over the years and have never had a failure of any kind. YMMV
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I have a B&C starter on the shelf I replaced after two dead starts. Upon opening it up I found the brushes badly worn (I got it used, total time unknown). I called B&C to order a set of new brushes and they wanted $130. I went across town and visited a friend of mine who rebuilds starters. He charged me a total of $7.00 as I recall for an identical new brush assembly. In the mean time I put an NL on and shelved the repaired B&C.

If it makes one feel better about a part that its got some sort of gold stamp that says "aviation" on it and you're more comfortable paying 4-5X more for that knock youself out. I've found it more wise to go the other way.
 
On several C172's and 177 Cardinals during the 70's and 80's the TSO'd alternator for Lyc. 320's and 360's was virtually identical to that found on Ford 1/2 ton trucks. The aviation version had the diodes epoxied in place for vibration tolerance and the center shaft was not longer than the pulley face. They even used the same external voltage regulator. My first ship used the Cessna alternator for a few years. Then I borrowed the alternator from my retired truck about 9 years ago. It bolted in with no issues and is still working fine with about 1000 hours of reliable service. I have the Cessna alt. rebuilt & waiting if and when needed. I was just lucky that I had compatible components.

Second ship has a B&C with it's own matched regulator. It has been good to me so far.

If I was building new I would carefully consider some of the proven automotive alternators mentioned earlier in this thread.
 
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