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RV-14 Thunderbolt Engine Accessory Pump

gregfuess

Well Known Member
Hi All, I got a call from Lycoming today about the options on my Thunderbolt engine. OTher than colors and ignition, the only option is whether to have the 2-1/2 lb accessory pump installed or not. traditionally used for a vacuum pump, Chris Gaymon suggested that the most common application today is to turn a backup alternator. The Van's RV-14s do NOT have this accessory.

Did you get the accessory pump drive? Are you glad you did or didn't? If you did, what do you use it for? Is there a question I am not considering?

Thanks for the help.
 
Standby alternator

The pad mount was standard on the stock Thunderbolt IO390 (Not EXP) and since I have an energy dependent engine I added a standby alternator. Reading the primary alternator failure rate I would be glad I have this option even if I did not have a energy dependent system. Although I would not fly far (More than 2 hours VFR) if I did not have a energy dependent system I would be ok flying more than that with a standard system. The load on the airframe easily is covered by a standby alternator. I would add the extra weight, exercise more and include a standby alternator. It's a personal choice of course and what allows us to be experimental builders.
 
I opted FOR the accessory drive on my Thunderbolt. Although I haven’t bought it yet, I plan to install a Monkworkz Generator to the accessory drive.
 
In my RV-14A I have the earlier Thunderbolt IO390 Exp which included the accessory case. I mounted a B&C stand-by alternator on the vacuum pump pad because, in my opinion, having electricity is important in an all electric airplane. I periodically shut down the primary alternator and operate the airplane on the stand-by. Output is dependent on rpm, but at cruise there is no problem operating everything. Peace of mind. :rolleyes:
 
In my RV-14A I have the earlier Thunderbolt IO390 Exp which included the accessory case. I mounted a B&C stand-by alternator on the vacuum pump pad because, in my opinion, having electricity is important in an all electric airplane. I periodically shut down the primary alternator and operate the airplane on the stand-by. Output is dependent on rpm, but at cruise there is no problem operating everything. Peace of mind. :rolleyes:

Same here. If one of them is getting weak, I want to know about it sooner rather than later. I do the same thing with my dual fuel pumps, and for the same reason.
 
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