Generators and alternators

[VictorGolf]

Does anybody on the forum know if it's possible/allowable to modify a Lycoming 0-235-C2A to take an alternator/solid state regulator to replace the generator and old style voltage regulator? The latter pieces of kit don't seem to be the most reliable and service life seems variable in the extreme. Please be gentle, I'm a civil not electrical engineer.

[hatzflyer]

Simple answer..yes its possible, yes its allowable.
Qualified answer...it depends what the engine is in. If its LAA not too much of a problem.
If its C of A you will need a mod. The cost of the paperwork alone will more than pay for you to replace the generator/ regulator 10 times over!

[Windy Militant]

VictorGolf is it installed in a C of A or LAA permit Aircraft? either way it's a case of you can but may not, well until you've submitted a modification application to whichever authority looks after your aircraft.
A quick look at the LAA Standard mod list doesn't show anything like this but an enquiry to engineering may uncover a mod that's not yet been posted on the web site.
If it's CAA then I'll let those more knowledgeable pass on their wisdom.
either way best of luck.;)

[VictorGolf]

Thanks for the info so far. The engine is in an Airtourer which is currently in Annex 2 on a UK CAA Cof A. The Type Certificate is held by the Airtourer Co-Op in Oz and I've asked them if anybody has done it down there. I guess it's a conversation wth the Belgrano if they have. Hatz I wasn't too sure about your reply. Did you suggest that it would be worthwhile?

[AC-DC]

I know nothing about your aircraftbut is did the convertion under their national CAA before it all became EASA then you can do it without the CAA blessing but you will have to prove that it was done.

[Pilot DAR]

I have done considerable work in this area. Yes, it can be done, though there may be various regulatory requirements to be met.

Be alert to the fact that alternators with internal regulators (common to most cars etc.), are less well suited to aircraft. The reason is that there is much less circuit opportunity to include an over voltage system, to remove that alternator from the circuit, if a system failure takes it over voltage. This has happened to me, and will burn out a lot of expensive radios and bulbs, if they are on when it happens. It is a certainty that the pilot will not get these turned off after becoming aware of the overvoltage, before damage is done.

The are additional circuits, sometimes referred to as "crowbar" circuits, which can provide this protection. The saving in a compact simple alternator installation, can be lost if you melt some expensive radios. This is one reason that internaaly regulated alternators are not common in certified installations. I do agree though that the reliability of alternators and regulators is going up, and such failures are less common. Combined with the fact that modern avionics will often tolerate voltages up to 30 volts, the risk is reduced. Understand what the implications are before you take the simple route though...

Pilot DAR