True HAC carbs

[C5Engineer 1170]

Years back BING used to sell a carb that was different from the standard Bing 54. They are supposedly a true High Altitude Compensating carb. They sold for close to $800 back in the day for a set. I have a chance to grab to some brand new ones for around $500. If they will do the same thing as the Hac mixture control I'd prefer to go this route so I don't have to mess with the mixture control. It would only take once to forget to enrichen it coming down from 10K to burn up your engine. Curious if anyone is familiar with these. I only know one guy that has a set and he said his EGT's stay at 1150 no matter what altitude he goes to. Is there a reason they stopped selling them?? Thoughts??

Some good reading here on the CPS site

http://www.800-airwolf.com/pdffiles/ARTICLES/part35.pdf

[napierm 2]

Tom Olenik worked with Rotax and had the HAC dialed in only to have Rotax quit selling them.

The Hacman works pretty well. I never forgot to look at those EGT's in flight and the adjustment range is small enough that you would really have to be asleep to damage the engine. However if you worry about it get an EGT with an alarm. Such a thing can be made with comparitors if you want to do an electronics project.

It is very nice to be able to climb up and catch a tailwind. Also nice to be able to enrich the midrange if needed during a descent. Can't do that with the HAC.

BTW, there wasn't much different about the carbs. In fact all the new 54's sold now have the same modification. It's a port in the venturi that give you "ported vacuum" to run the HAC. I added the port on one of my older carbs but you can pick up one that already has it on ebay. You only need one.

FWIW,

Mark

Edited 15 Jul 2010 by napierm