rv7charlie
Well-Known Member
Hi thjakits, welcome to the conversation!
Just to address the latter parts of your post, the rotary just doesn't have a lot of torque (power basically comes from rpm in the rotary's case). There's no practical way to get low rpm torque out of a rotary, largely because of the very short 'stroke', for lack of a better term. High torque piston engines tend to have relatively long stroke cranks; something that's almost impossible to do with a Wankel style rotary. Mazda does have a prototype engine (the 16X) that has a bigger eccentric (stroke), as well as all aluminum construction, that rotary flyers have been salivating over for a long time, but there's no real evidence we'll ever see it in production.
I owned a great 'automatic pitch adjustment' prop about 25 years ago (on a Lyc); Bernie Warnke was famous for his 'almost constant speed' wood props back in the 1980s-1990s. But that wouldn't buy you much with a rotary; there's no real power until you get up in the 5k rpm range and above.
I don't recall any emphasis on ceramic side housings, unless you're talking about aluminum with a high tech wear surface. You can buy those now, but they're very pricey, and I don't know anyone who's used them in an a/c designed to be actually used. (There's the time-to-climb record holder, but I doubt that engine ever ran longer than 20 minutes at a time, and probably has fewer than 100 hrs total on the engine (with a couple of rebuilds in the mix for various reasons).
Using automotive engine control (if you mean 'from the car') is a very dicey proposition, because modern car controllers have literally hundreds of thousands of lines of code running their cpu's, most of which ties the engine to the rest of the car in ways that are hard to 'hack' around, and since the code isn't open source, there's no way to know whether we've hacked around every transmission shift point code, limp home mode, etc. People have been killed trying. There are several controller sources still available that have been extensively debugged on 'hot rod' ground vehicles that are much better (safer) options. The big hangup at the moment is the gear drive, now that Tracy is retired.
Belt drives: It's been done; there was a toothed belt version flying successfully on an amphib in the USA northwest for a number of years. But they tend to be bulky, require cooling air, and aren't really any lighter than a properly designed gearbox. Most people just won't trust a V-belt array on a high HP engine in a fast a/c, whether it's justified or not.
Charlie
Just to address the latter parts of your post, the rotary just doesn't have a lot of torque (power basically comes from rpm in the rotary's case). There's no practical way to get low rpm torque out of a rotary, largely because of the very short 'stroke', for lack of a better term. High torque piston engines tend to have relatively long stroke cranks; something that's almost impossible to do with a Wankel style rotary. Mazda does have a prototype engine (the 16X) that has a bigger eccentric (stroke), as well as all aluminum construction, that rotary flyers have been salivating over for a long time, but there's no real evidence we'll ever see it in production.
I owned a great 'automatic pitch adjustment' prop about 25 years ago (on a Lyc); Bernie Warnke was famous for his 'almost constant speed' wood props back in the 1980s-1990s. But that wouldn't buy you much with a rotary; there's no real power until you get up in the 5k rpm range and above.
I don't recall any emphasis on ceramic side housings, unless you're talking about aluminum with a high tech wear surface. You can buy those now, but they're very pricey, and I don't know anyone who's used them in an a/c designed to be actually used. (There's the time-to-climb record holder, but I doubt that engine ever ran longer than 20 minutes at a time, and probably has fewer than 100 hrs total on the engine (with a couple of rebuilds in the mix for various reasons).
Using automotive engine control (if you mean 'from the car') is a very dicey proposition, because modern car controllers have literally hundreds of thousands of lines of code running their cpu's, most of which ties the engine to the rest of the car in ways that are hard to 'hack' around, and since the code isn't open source, there's no way to know whether we've hacked around every transmission shift point code, limp home mode, etc. People have been killed trying. There are several controller sources still available that have been extensively debugged on 'hot rod' ground vehicles that are much better (safer) options. The big hangup at the moment is the gear drive, now that Tracy is retired.
Belt drives: It's been done; there was a toothed belt version flying successfully on an amphib in the USA northwest for a number of years. But they tend to be bulky, require cooling air, and aren't really any lighter than a properly designed gearbox. Most people just won't trust a V-belt array on a high HP engine in a fast a/c, whether it's justified or not.
Charlie