Plugs Up?

cjensen · #1 09-09-2005, 12:53 PM

i know of one or two plugs up rotary installations, one of them is in a Lancair something or other. other than additional room under the top cowl, can anyone shed some light on the advatages of this method of install? i know the engine probably doesn't care how it sits, but what about the oil pan and oil?

Rotary10-RV · #2 09-09-2005, 01:40 PM

Quote:

Originally Posted by cjensen

i know of one or two plugs up rotary installations, one of them is in a Lancair something or other. other than additional room under the top cowl, can anyone shed some light on the advatages of this method of install? i know the engine probably doesn't care how it sits, but what about the oil pan and oil?

Chad,
Unless you have serious cowl problems it is advisable to avoid the plugs up configuration. The engine runs fine, but you have to re-engineer the pan, oil drain, engine mounts, etc... the list goes on. The engine fits in an RV cowl without problems. Bernie Kerr just finished his RV-9, there are photo links on Tracy Crooks web site. The rotary can be made to run fine this way, (plugs up) but it isn't for the feint-hearted to do the conversion. If you have a cowl line problem it is a better idea to run a PSRU with some offset. PowerSport's drive gets you about 3 inches. Marcotte makes a similar drive as well. Powersport's is well designed and very clean, if a bit heavy. You can fit a planetary in all but the tightest cowls if you're careful. Check out Mistral's site for a good example of tight fitting intake runners for good cowl clearance. www.mistralengines.com
Bill Jepson

rv6ejguy · #3 09-09-2005, 03:12 PM

Plugs up is sometimes the only solution with a tight cowling, high thrust line and planetary redrive with no offset but involves many mods. See the Lancair here: http://www.sdsefi.com/air22.html

The Marcotte internal helical gear gives you just under 2 inches of very useful offset, depending on ratio. The Powersport one, if available, would be similar I think but don't have one to measure. The RV10 does have a relatively low cowling line so careful measurements should be made before you decide on the redrive and intake manifold setup. If you'd like station measurements from thrust line to cowling top, I have my finish kit and can take my tape measure out.

Hmmmmmmm!

cjensen · #4 09-09-2005, 03:44 PM

thanks for the info guys. i'm not planning on this installation at all, i'm just a curious guy. i've heard of this a couple of times, but not in an RV. i know the lancairs are tight for a rotary, and i figured that's why he did it that way. at this point, i am planning to use a powersport fwf kit for my -7, but that's ways off (hopefully they'll still be available!). i've been talking with ray at powersport since osh, and have talked with francois at mistral as well.

sorry about the misunderstanding in the original post. i just wanna know stuff in general.