ilmailija,

Go to the "radio/servo" Forum and read about Hitec servos. I use all hitec digitals in the 56 and 59 series radios on three planes and have not had a problem. However, there have been complaint from some people about their quality. Hitec, themselves says on there somewhere that the 54 series digitals are for sport flying only, not aerobatic planes. The rationale beats the heck out of me. because they even knock their own 56 series a little. Their web site doesn't say this. but their response to peoples complaints about the 56/54 series is that this are not high performance servos. go figure.