I Have a Question: Would you know what the minimum Hp power is needed to power an KR1 or KR-2'
What the absolutely, minimum configuration you have seen fly? On Mon, Oct 18, 2021 at 7:46 AM Mark Langford <m...@n56ml.com> wrote: > I've been down the road on Corvairs, and I still have to say that they > are wonderful engines. Six smooth cylinders, and if one quits, you can > still take off and fly the plane home (just ask Steve Makish). Try that > with ANY four cylinder aircraft engine. Now that we've fixed the broken > crank issues with fifth bearings from vendors like Sport Performance > Aviation (just as Revmaster and GPASC solved the VW crank breakage with > a front bearing), not a single Corvair crank has broken. Parts are > relatively inexpensive, and certainly more plentiful than O-200's. > Corvairs are dirt simple to rebuild...even easier than the four cylinder > VW engine! > > As for O-200 performance vs Corvair on a KR2S, they are almost exactly > the same. I've "raced" Larry Flesner in his KR2S with N56ML, and I was > a bit faster in speed and climb, but you could credit that to the "new > airfoil", and probably some penalty to Larry's plane for being a little > larger all the way around, plus just the pilot weight, maybe prop > diameter....so call it even. Fuel consumption in the O-200 is > considerably higher though, at least partially due to lower compression > and a "stone-age" carburetor on it. > > Mininum 150 mph in a KR2 or KR2S is a given, with any kind of reasonable > engine. N891JF with a 2180 will do 165 mph wide open, and with the > right prop, 170 mph. But I don't like wasting fuel like that, so I > usually do 150 mph true airspeed. At 150 I usually burn about 3.3 gph! > > Even in Corvair powered N56ML, I would fly throttleed back at something > like 165 mph most of the time, burning around 4 gph. What's not to like > about that? And that's on auto-fuel....a considerable operational cost > dropper, not to mention environmental issues like more lead in the air. > > In short, they all work, but the 4 cylinder VW is more maintenance with > more frequent valve jobs. Corvairs just don't have valve issues. I > think Joe Horton' splane has over 1100 hours on the same set of heads > and valves that he started with. I doubt that happens on VWs, at least > not if you've every seen one suck a valve after the head breaks off > (been there, done that too). > > As for KR2 length, I can tell you it makes a real difference, especially > in landing a tail dragger. I've owned and flown both, and it's not > trivial. But with a wide runway, there's nothing wrong with a KR2 in > landing. It's possible to make it longer....Jim Hill did it and so did > Stefan in the Netherlands, and it's pretty easy to lengthen the > horizontal stabilizer and rudder a few inches to help stability. Some > folks say there's no problem with the KR2 stability, but they've > probably never flown a KR2S either..... > > Mark Langford > m...@n56ml.com > http://www.n56ml.com > Huntsville, AL > > On 10/18/2021 12:40 AM, G R Pickett wrote: > > I know this has been hashed out before, but when it comes to a KR2 > original length, what are some opinions ? > > > > I want to complete a plane that's definitely faster than 150 mph. > Really, closer to 175 kts would be even better. I know that some of my old > acquaintances in the '90s were getting those speeds (safely) with O-200's, > but that was before the Corvair engines became popular. And yes, I > understand that the KR2S came about to calm down the twitchiness of the > short KR's, but I have a short one, so I'm going to build retro. Anyway, I > have two of them. > > > > Corvair Pro's: Cheaper to build and get replacement parts for. More > modern design. 6 cylinders run smoother. Designed for unleaded fuel. > Easier and cheaper to upgrade HP. Capable of more HP at altitude than a > VW. Narrower deck than a Continental, potentially less drag. Seems about > as easy to work on as a VW. > > Continental Pro's: proven aviation engine. Lots of parts, mechanical > knowledge, and mechanics out there. Most likely easier to fix at more > airports, when necessary. Dual ignition system. Probably in more KRs, so > most known problems have more solutions. > > Corvair Cons: Limited number of sources for aviation-grade > parts/knowledge. Fewer sources for high grade parts. More expensive than > a VW engine. Heavier than a Continental. Not an aircraft engine, so > longer flight testing required. > > Continental Con's: It's an aircraft engine, so parts are always higher > priced. Intended for leaded fuel, so when that goes away, it's still more > expensive to operate, even if the fuel burn is lower (sort of a weak > argument, since so many are run on MoGas anyhow). > ________________________________ > -Please see LIST RULES and KRnet info at http://www.krnet.org/info.html > -Change list delivery options at > https://list.krnet.org/list/krnet.list.krnet.org/ Affinity List Info Board > -Search recent KRnet Archives at > https://list.krnet.org/empathy/list/krnet.list.krnet.org/ > -Search <https://list.krnet.org/empathy/list/krnet.list.krnet.org/-Search> > John Bouyea's decades of archive at > https://www.mail-archive.com/krnet@list.krnet.org/ > ________________________________ -Please see LIST RULES and KRnet info at http://www.krnet.org/info.html -Change list delivery options at https://list.krnet.org/list/krnet.list.krnet.org/ Affinity List Info Board -Search recent KRnet Archives at https://list.krnet.org/empathy/list/krnet.list.krnet.org/ -Search John Bouyea's decades of archive at https://www.mail-archive.com/krnet@list.krnet.org/
