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Standby / backup alternator for the TB20 (and other types)

I guess you also wouldn't drive an electric car?

If that battery catches fire you can stop and jump out

I think electric cars are a crap idea. With much of Europe dumping nuclear power, all you are doing is shifting the emissions to a power station whose exhaust gets dumped in somebody else's neighbourhood.

The good thing about the backup alternator is that you can continue a flight all the way to the destination. With another battery, you have extended your 30-60 minute time by a similar amount, which is of a marginal benefit. I have done loads of flights where one spends several hours at say FL170, VMC on top, and any descent would mean severe icing and turbulence.

I am not giving up on this just yet...

Administrator
Shoreham EGKA, United Kingdom

It clearly looks like a simple anticlockwise rotation of the existing elbow

That male thread on the 'T' elbow, or its associated female socket could well be a 'tapered thread'.

A 'tapered thread' produces a tight seal over a wide range of positions. A 360° turn will often still be 'tight'. Sealant, may be. But if it is a tapered thread it makes life easy. Care has to be taken with tapered threads as they never tighten to a 'stop'. Over-tighten can 'split' the female socket. One should always be aware when dealing with 'tapered threads'.

Regret no current medical
Was Sandtoft EGCF, North England, United Kingdom

You can purchase very good Lithium manganese packs designed for pedelecs. Two 16Ah packs would get me back home from pretty much everywhere. Pedelec packs are good because they are designed for high current draw (250W motor). In addition they would give me the ability to safely operate my avionics on the ground without the engine running.

Achim, how do you get the power into your panel from your batteries? Using the cigarette socket?

YPJT, United Arab Emirates

That will depend on the electric system of the airplane. The cigarette lighter could be one way or a connection to the avionics rail. In my case I would most likely install a 2nd avionics master switch that would connect the avionics bus and the battery. On the ground, I could use that to operate the avionics without draining the main battery and in flight it would be turned on to charge the 2nd battery.

A standby alternator costs quite a bit of money plus significant cost for labor and certification, adds considerable weight and makes access to the engine accessories harder. Also in a single bus aircraft, it would not help in cases where the problem is with the electric system (e.g. solenoid). For much less I could get high quality batteries and a system that gets me home safely plus has a great added value of being able to operate the avionics on the ground.

With a dual bus aircraft (e.g. Cessna 400), I think a 2nd alternator is a great thing to have.

PS: This is another great option, doesn't even require a working engine

PS: This is another great option, doesn't even require a working engine

Also known as a RAT....If it's good enough for an airliner....why not?

YPJT, United Arab Emirates

I had a look at the B&C alternator for my aircraft, just out of curiosity. Even though I have a very similar engine to Peter's, including the stupid dual magneto, I don't have a free drive pad due to the turbo scavenger pump. Always wondered why I couldn't spot that free drive pad I was expecting

Update:

I have the Lycoming hydraulic pump converter in my hand. It's not a new part but mechanically it is absolutely perfect, with almost zero wear. It will be released to service via an overhaul (NDT, etc).

The next job is to take off that drive point cover and see what is behind it. Either there is a drive gear in there (in which case the drive adapter can be temporarily attached and correct rotation checked) or there isn't (in which case the engine will have to come out, and really it will be a job at overhaul time).

B&C have STCs for a PA32 (IO-540 too) which use this same drive adapter, which should smooth the way for a 337 field approval.

Administrator
Shoreham EGKA, United Kingdom

In the Cirrus (2 alternators, no vaccuum in the SR22) : Batt 1 is 24 V / 10 aH... Batt 2 is made of two 12 volt / 7 ah sealed acid batteries batteries connected in series to provied 24 V

PS: This is another great option, doesn't even require a working engine

The Basic Aircraft wind driven generator is sold and used on a lot of aircraft for primary electrical power too. I've not heard of any problems with it except that its a little large in diameter (i.e. for aerodynamic drag), which is often what happens when you design a generator to be light in weight.

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