X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from fed1rmmtao106.cox.net ([68.230.241.40] verified) by logan.com (CommuniGate Pro SMTP 5.2.12) with ESMTP id 3527915 for flyrotary@lancaironline.net; Wed, 04 Mar 2009 22:14:58 -0500 Received-SPF: none receiver=logan.com; client-ip=68.230.241.40; envelope-from=rv-4mike@cox.net Received: from fed1rmimpo01.cox.net ([70.169.32.71]) by fed1rmmtao106.cox.net (InterMail vM.7.08.02.01 201-2186-121-102-20070209) with ESMTP id <20090305031421.LNYG22254.fed1rmmtao106.cox.net@fed1rmimpo01.cox.net> for ; Wed, 4 Mar 2009 22:14:21 -0500 Received: from wills ([68.105.85.56]) by fed1rmimpo01.cox.net with bizsmtp id PFEK1b00S1CvZmk03FEM03; Wed, 04 Mar 2009 22:14:21 -0500 X-Authority-Analysis: v=1.0 c=1 a=RgAroyKy78wA:10 a=U1ZaYnf293oA:10 a=IDHyWt4XAAAA:8 a=N8B9JuSIAAAA:8 a=kviXuzpPAAAA:8 a=ObOvawjT8RqBhJ7ykesA:9 a=_Q1pPTU_uxeu7DvmBkAA:7 a=fAfwJopFJCqBxtTaC-y1bP_xvQwA:4 a=oltf0pfCdT4A:10 a=4vB-4DCPJfMA:10 a=CQCehMHTrCnCsk1a:21 a=g86_PYCJ884Aujp1:21 a=pGLkceISAAAA:8 a=Ia-xEzejAAAA:8 a=pCdupeT1pHj2XG4cXeUA:9 a=qeNPzzjyo8GdoiCVADoA:7 a=oRM09XKiJs25Nf9ytpbOQSXk0C4A:4 a=AfD3MYMu9mQA:10 a=MSl-tDqOz04A:10 a=EzXvWhQp4_cA:10 X-CM-Score: 0.00 Message-ID: <003d01c99d40$797db8c0$38556944@wills> From: "Mike Wills" To: "Rotary motors in aircraft" References: Subject: Re: [FlyRotary] Re: Questions on buying a rotary plane Date: Wed, 4 Mar 2009 19:14:19 -0800 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_003A_01C99CFD.6B0E2D80" 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_003A_01C99CFD.6B0E2D80 Content-Type: text/plain; charset="Windows-1252" Content-Transfer-Encoding: quoted-printable Dave, I remember looking at this when you posted about it previously. Not = sure a race is quite what I had in mind, but better than nothing. I = think documented performance numbers at typical cruise configurations = would be more useful. Cant argue with your bang for the buck numbers - = one of the primary reasons I went rotary as well. I still dont think = it's fair to claim an economy victory based on the price/use of Mogas = because you CHOOSE to burn it and your Lyc powered RV buddies CHOOSE not = to. I dont know about you guys but the typical questions/comments are: 1) It will weigh more than a Lyc powered RV (in my case true). 2) It will be slower and climb slower than a Lyc powered RV (the jury is = out in my case). 3) Those rotaries burn more gas than an aircraft engine. 4) You're crazy to fly behind a car engine. My responses to 1 and 2 are maybe, to 3 is it varies depending on how = its operated. My response to 4 depends on my mood and how the comment is = made. Anyway, it would sure be nice if a number of guys flying did as good a = job of documenting and advertising their performance as they do = documenting their build process. There are enough flying now to have = some statistical relevance. I'd like to be able to point to a website = when someone quizzes me on performance. Mike ----- Original Message -----=20 From: David Leonard=20 To: Rotary motors in aircraft=20 Sent: Tuesday, March 03, 2009 9:12 PM Subject: [FlyRotary] Re: Questions on buying a rotary plane Hey Mike, I have done such a real world direct comparison. =20 We did a race where where were filled tanks before and after to = compare fuel burn as well as speed. Scroll down here to see the = results: http://www.rvproject.com/race.html Bear in mind: 1) the fastest 2 planes were tandem, and had an advantage. 2) the slowest 2 planes were trying to win the efficiency contest = rather than the speed contest. Of the 5 remaining planes, mine was right in the middle in terms of = speed and fuel burn. All other planes were 180 or 200 hp lycs with c/s = props. I had the only f.p. prop and my installation cost at least $15k = less than any of the others. Because I was the only one able to use = MOGAS, my fuel cost were the cheapest (of the non-economy flight profile = group). Bottom line: the rotary proved to be very comparable in terms of power = and fuel burn. (as others have noted). --------- I now have 370 hours and almost never remove the cowl anymore. I fly = it hard and put it away wet. I have not had an engine or engine systems = issue in nearly 200 hrs. =20 Compare that the the first 100 hrs where I was putting in almost 10 = hrs of maintenance for each our of flying and she has really come a long = way.=20 Way worth it! --=20 David Leonard Turbo Rotary RV-6 N4VY http://N4VY.RotaryRoster.net http://RotaryRoster.net On Tue, Mar 3, 2009 at 7:55 PM, Mike Wills wrote: 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=92m 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=92s. 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 =96 or worse. I=92ve 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=92t know why =96 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_003A_01C99CFD.6B0E2D80 Content-Type: text/html; charset="Windows-1252" Content-Transfer-Encoding: quoted-printable
Dave,
 
 I remember looking at this when = you posted=20 about it previously. Not sure a race is quite what I had in mind, but = better=20 than nothing. I think documented performance numbers at typical cruise=20 configurations would be more useful. Cant argue with your bang for = the buck=20 numbers - one of the primary reasons I went rotary as well. I still dont = think=20 it's fair to claim an economy victory based on the price/use of Mogas = because=20 you CHOOSE to burn it and your Lyc powered RV buddies CHOOSE not=20 to.
 
 I dont know about you guys but = the typical=20 questions/comments are:
 
1) It will weigh more than a Lyc = powered RV (in my=20 case true).
2) It will be slower and climb slower = than a Lyc=20 powered RV (the jury is out in my case).
3) Those rotaries burn more gas than an = aircraft=20 engine.
4) You're crazy to fly behind a car=20 engine.
 
My responses to 1 and 2 are maybe, to 3 = is it=20 varies depending on how its operated. My response to 4 depends on my = mood and=20 how the comment is made.
 
Anyway, it would sure be nice if a = number of guys=20 flying did as good a job of documenting and advertising their = performance as=20 they do documenting their build process. There are enough flying now to = have=20 some statistical relevance. I'd like to be able to point to a website = when=20 someone quizzes me on performance.
 
Mike
----- Original Message -----
From:=20 David=20 Leonard
Sent: Tuesday, March 03, 2009 = 9:12=20 PM
Subject: [FlyRotary] Re: = Questions on=20 buying a rotary plane

Hey Mike,

I have done such a real world direct=20 comparison. 

We did a race where where were filled tanks = before=20 and after to compare fuel burn as well as speed.  Scroll down = here to see=20 the results:
http://www.rvproject.com/race= .html

Bear=20 in mind:
1) the fastest 2 planes were tandem, and had an = advantage.
2)=20 the slowest 2 planes were trying to win the efficiency contest rather = than the=20 speed contest.

Of the 5 remaining planes, mine was right in the = middle=20 in terms of speed and fuel burn.  All other planes were 180 or = 200 hp=20 lycs with c/s props.  I had the only f.p. prop and my = installation cost=20 at least $15k less than any of the others.  Because I was the = only one=20 able to use MOGAS, my fuel cost were the cheapest (of the non-economy = flight=20 profile group).

Bottom line: the rotary proved to be very = comparable in=20 terms of power and fuel burn. (as others have = noted).
---------
I now=20 have 370 hours and almost never remove the cowl anymore.  I fly = it hard=20 and put it away wet.  I have not had an engine or engine systems = issue in=20 nearly 200 hrs. 

Compare that the the first 100 hrs where = I was=20 putting in almost 10 hrs of maintenance for each our of flying and she = has=20 really come a long way.

Way worth it!

--
David=20 Leonard

Turbo Rotary RV-6 N4VY
http://N4VY.RotaryRoster.nethttp://RotaryRoster.net


On Tue, Mar 3, 2009 at 7:55 PM, Mike Wills = <rv-4mike@cox.net>=20 wrote:
Glad I woke you guys up! = :-)
 
While it may appear from my post = that I was=20 trying to discourage this guy and am not happy with my rotary = powered=20 airplane that is not the case. I'm very happy with it. Will be even = happier=20 once I get all of the little glitches fixed so I can just fly=20 it.
 
 I simply wanted to make sure = William=20 understands what he's getting into. What appears to be a fairly = straight=20 forward mod is a lot more complicated than it appears and there are=20 potential pitfalls that are not necessarily obvious.
 
 My bad on the misread = regarding fuel=20 efficiency - he was talking about homebuilt aircraft = versus=20 factory built planes, not rotaries versus certified engines. = I think=20 he's still way off base here which was why I replied to his=20 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=20 consumption I got with my Lyc powered RV-6A at cruise and I = know there=20 are certainly enough flying Lyc powered RVs to pretty firmly = establish=20 a cruise performance baseline. Since there are more flying = rotary=20 powered RVs than other types, seems like we should be able to get at = least=20 an idea of how they compare. Lets challenge the rotary RV = fliers here=20 to post real cruise performance (altitude, TAS, fuel consumption) = and answer=20 the question. Or give me a year and 100 hours and I'll let you know = how my=20 RV-4 stacks up against the -6A for a data point.
 
 As for your performance = against=20 conventional powered Velocities, thats great news. I think thats one = of the=20 significant short comings of our little group here. Common = perception is=20 that rotaries are gas hogs and we dont do anything to accurately = document=20 and advertise our performance.
 
 Mark, I agree that burning = Mogas=20 definitely makes a big difference economy-wise. But that's a red = herring.=20 You could legally burn Mogas in a Lyc/Cont also - just that most = guys who=20 are too conservative to choose an auto conversion are also too = conservative=20 to burn Mogas. Burning Mogas isnt the exclusive territory of the=20 rotary. I personally know a guy with a 200HP Lyc in an RV-8 who = has=20 burned Mogas exclusively for years. Really what it comes down to is=20 convenience and comfort. Lets be fair, compare apples to = apples,=20 and while we're at it throw in the additional cost and hassle of = having to=20 pour in 2 stroke oil for your rotary (assuming you do that as most = seem to=20 do).
 
 I do totally agree with you = on the price=20 of parts. And that was one of my huge motivations for going this = route. But=20 really the biggest motivation was to do something a little = different. When=20 my RV-4 finally makes it's appearance at a fly-in (hopefully this = year) it's=20 not going to be lost in the sea of belly button RVs that show=20 up.
 
Mike Wills
RV-4 N144MW
 
 
-----=20 Original Message -----
From:=20 Al Gietzen
To:=20 Rotary = motors in=20 aircraft
Sent:=20 Monday, March 02, 2009 9:51 PM
Subject:=20 [FlyRotary] Re: Questions on buying a rotary plane

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

 

Mike;

 

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

 

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

 

Al=20 =  



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