X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from fed1rmmtao103.cox.net ([68.230.241.43] verified) by logan.com (CommuniGate Pro SMTP 5.2.12) with ESMTP id 3526244 for flyrotary@lancaironline.net; Tue, 03 Mar 2009 22:55:54 -0500 Received-SPF: none receiver=logan.com; client-ip=68.230.241.43; envelope-from=rv-4mike@cox.net Received: from fed1rmimpo03.cox.net ([70.169.32.75]) by fed1rmmtao103.cox.net (InterMail vM.7.08.02.01 201-2186-121-102-20070209) with ESMTP id <20090304035508.GBDC4363.fed1rmmtao103.cox.net@fed1rmimpo03.cox.net> for ; Tue, 3 Mar 2009 22:55:08 -0500 Received: from wills ([68.105.85.56]) by fed1rmimpo03.cox.net with bizsmtp id Nrv61b0031CvZmk04rv8oU; Tue, 03 Mar 2009 22:55:08 -0500 X-Authority-Analysis: v=1.0 c=1 a=RgAroyKy78wA:10 a=U1ZaYnf293oA:10 a=alPYGxDObUvuHxXF99MA:9 a=EfitChniEWY1fMiM2XAA:7 a=JRXpqSBJQ87px-WzWB33daavD3EA:4 a=tqucuuI3bnEA:10 a=xU-GPgNymTfnkLrd:21 a=ucHvMWFqoVNUAqNf:21 a=kviXuzpPAAAA:8 a=Ia-xEzejAAAA:8 a=-ukEId98t_EynAzBcCoA:9 a=kO3sPl_7dGLBChD-aOQA:7 a=S_Z3Quubr8F2qm7P9B38NTw8igQA:4 a=AfD3MYMu9mQA:10 a=4vB-4DCPJfMA:10 a=EzXvWhQp4_cA:10 a=2zHLvueWmWWaMKlG:21 a=dtp_0l6ayY5CEBng:21 X-CM-Score: 0.00 Message-ID: <006101c99c7d$016aeec0$38556944@wills> From: "Mike Wills" To: "Rotary motors in aircraft" References: Subject: Re: [FlyRotary] Re: Questions on buying a rotary plane Date: Tue, 3 Mar 2009 19:55:05 -0800 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_005E_01C99C39.F2EF7CA0" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2900.3138 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.3350 This is a multi-part message in MIME format. ------=_NextPart_000_005E_01C99C39.F2EF7CA0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Glad I woke you guys up! :-) While it may appear from my post that I was trying to discourage this = guy and am not happy with my rotary powered airplane that is not the = case. I'm very happy with it. Will be even happier once I get all of the = little glitches fixed so I can just fly it. I simply wanted to make sure William understands what he's getting = into. What appears to be a fairly straight forward mod is a lot more = complicated than it appears and there are potential pitfalls that are = not necessarily obvious. My bad on the misread regarding fuel efficiency - he was talking about = homebuilt aircraft versus factory built planes, not rotaries versus = certified engines. I think he's still way off base here which was why I = replied to his post. Al, I dont know anyone who actually KNOWS what BSFC they acheive with = their Lyc/Cont. I know that low .40s is a published number that is stuck = in my head. I know what kind of fuel consumption I got with my Lyc = powered RV-6A at cruise and I know there are certainly enough flying Lyc = powered RVs to pretty firmly establish a cruise performance baseline. = Since there are more flying rotary powered RVs than other types, seems = like we should be able to get at least an idea of how they compare. Lets = challenge the rotary RV fliers here to post real cruise performance = (altitude, TAS, fuel consumption) and answer the question. Or give me a = year and 100 hours and I'll let you know how my RV-4 stacks up against = the -6A for a data point. As for your performance against conventional powered Velocities, thats = great news. I think thats one of the significant short comings of our = little group here. Common perception is that rotaries are gas hogs and = we dont do anything to accurately document and advertise our = performance. Mark, I agree that burning Mogas definitely makes a big difference = economy-wise. But that's a red herring. You could legally burn Mogas in = a Lyc/Cont also - just that most guys who are too conservative to choose = an auto conversion are also too conservative to burn Mogas. Burning = Mogas isnt the exclusive territory of the rotary. I personally know a = guy with a 200HP Lyc in an RV-8 who has burned Mogas exclusively for = years. Really what it comes down to is convenience and comfort. Lets be = fair, compare apples to apples, and while we're at it throw in the = additional cost and hassle of having to pour in 2 stroke oil for your = rotary (assuming you do that as most seem to do). I do totally agree with you on the price of parts. And that was one of = my huge motivations for going this route. But really the biggest = motivation was to do something a little different. When my RV-4 finally = makes it's appearance at a fly-in (hopefully this year) it's not going = to be lost in the sea of belly button RVs that show up. Mike Wills RV-4 N144MW ----- Original Message -----=20 From: Al Gietzen=20 To: Rotary motors in aircraft=20 Sent: Monday, March 02, 2009 9:51 PM Subject: [FlyRotary] Re: Questions on buying a rotary plane I dont know where you got the idea that rotaries are more fuel = efficient. Lycosaurs/Continentals typically have BSFCs in the low .40s. = The commonly accepted number for a rotary is about .50. Some here seem = to do better, others worse.=20 Mike; I'm not disagreeing with the points in your message; but I am = wondering if you know anybody actually flying a Lyc/Cont and achieving = BSFC in the low 40's. I see numbers like .43 or .45 bandied about, but = I guess no one leans enough when flying to get that for fear of burning = out a valve - or worse. I've yet to hear from anyone flying a Velocity = like mine with a Lyc who can surpass the speed/fuel burn that I get with = the 20B. I don't know why - it surprised me; but there it is. I think in the real world operation the BSFCs are comparable. I may = have a bit lower drag because of smaller cowl; or other factors. Al =20 ------=_NextPart_000_005E_01C99C39.F2EF7CA0 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
Glad I woke you guys up! = :-)
 
While it may appear from my post that I = was trying=20 to discourage this guy and am not happy with my rotary powered airplane = that is=20 not the case. I'm very happy with it. Will be even happier once I get = all of the=20 little glitches fixed so I can just fly it.
 
 I simply wanted to make sure = William=20 understands what he's getting into. What appears to be a fairly straight = forward=20 mod is a lot more complicated than it appears and there are potential = pitfalls=20 that are not necessarily obvious.
 
 My bad on the misread regarding = fuel=20 efficiency - he was talking about homebuilt aircraft versus = factory=20 built planes, not rotaries versus certified engines. I think he's = still way=20 off base here which was why I replied to his post.
 
 Al, I dont know anyone who = actually=20 KNOWS what BSFC they acheive with their Lyc/Cont. I know that low .40s = is a=20 published number that is stuck in my head. I know what kind of fuel = consumption I got with my Lyc powered RV-6A at cruise and I know = there are=20 certainly enough flying Lyc powered RVs to pretty firmly establish = a cruise=20 performance baseline. Since there are more flying rotary powered RVs = than other=20 types, seems like we should be able to get at least an idea of how they=20 compare. Lets challenge the rotary RV fliers here to post real = cruise=20 performance (altitude, TAS, fuel consumption) and answer the question. = Or give=20 me a year and 100 hours and I'll let you know how my RV-4 stacks up = against the=20 -6A for a data point.
 
 As for your performance against = conventional=20 powered Velocities, thats great news. I think thats one of the = significant short=20 comings of our little group here. Common perception is that rotaries are = gas=20 hogs and we dont do anything to accurately document and advertise our=20 performance.
 
 Mark, I agree that burning Mogas = definitely=20 makes a big difference economy-wise. But that's a red herring. You could = legally=20 burn Mogas in a Lyc/Cont also - just that most guys who are too = conservative to=20 choose an auto conversion are also too conservative to burn Mogas. = Burning Mogas=20 isnt the exclusive territory of the rotary. I personally know a guy = with a=20 200HP Lyc in an RV-8 who has burned Mogas exclusively for years. Really = what it=20 comes down to is convenience and comfort. Lets be = fair, compare apples=20 to apples, and while we're at it throw in the additional cost and hassle = of=20 having to pour in 2 stroke oil for your rotary (assuming you do that as = most=20 seem to do).
 
 I do totally agree with you on = the price of=20 parts. And that was one of my huge motivations for going this route. But = really=20 the biggest motivation was to do something a little different. When my = RV-4=20 finally makes it's appearance at a fly-in (hopefully this year) it's not = going=20 to be lost in the sea of belly button RVs that show up.
 
Mike Wills
RV-4 N144MW
 
 
----- Original Message -----
From:=20 Al = Gietzen=20
Sent: Monday, March 02, 2009 = 9:51=20 PM
Subject: [FlyRotary] Re: = Questions on=20 buying a rotary plane

 I dont know = where you got=20 the idea that rotaries are more fuel efficient. = Lycosaurs/Continentals=20 typically have BSFCs in the low .40s. The commonly accepted number = for a=20 rotary is about .50. Some here seem to do better, others worse.=20

 

Mike;

 

I=92m = not=20 disagreeing with the points in your message; but I am wondering if = you know=20 anybody actually flying a Lyc/Cont and achieving BSFC in the low = 40=92s. =20 I see numbers like .43 or .45 bandied about, but I guess no one = leans enough=20 when flying to get that for fear of burning out a valve =96 or = worse. =20 I=92ve yet to hear from anyone flying a Velocity like = mine with a=20 Lyc who can surpass the speed/fuel burn that I get with the 20B. I = don=92t=20 know why =96 it surprised me; but there it is.

 

I think = in the=20 real world operation the BSFCs are comparable.  I may have a = bit lower=20 drag because of smaller cowl; or other factors.

 

Al=20 =  

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