Or use a CR circular type & never be bothered by the 'wind up' or 'wind down' carry on... <img src="smile.gif" border="0">
Yeah, yeah. I admit I'm biased. But in fairness I did Oz PPL & CPL all on a slide type (calculators only allowed in the CPL Performance & Operation subject), then Oz IR, Oz/USA/UK ATPLs on a Jeppessen CR5. In 10 years instructing I taught with both types & my vote is definitely to the CR.
NB. I still have & will keep the Kane slide type. Accurate & durable - if you want to put up with the bulk of a slide & the weight of all its thick aluminium!