X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from rv-out-0506.google.com ([209.85.198.233] verified) by logan.com (CommuniGate Pro SMTP 5.2.12) with ESMTP id 3526309 for flyrotary@lancaironline.net; Wed, 04 Mar 2009 00:13:00 -0500 Received-SPF: pass receiver=logan.com; client-ip=209.85.198.233; envelope-from=wdleonard@gmail.com Received: by rv-out-0506.google.com with SMTP id b25so3234457rvf.7 for ; Tue, 03 Mar 2009 21:12:25 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:mime-version:received:in-reply-to:references :date:message-id:subject:from:to:content-type; bh=9Ms+ekSM0jwAMz2bc5wlShfoVbFmrdTBm3OQ2ngZOKc=; b=VVFhJxZ7IKpxD8+0zL6emKSp4s298jiqGwDZr1iKWuGR+CCKQFV6Wr8oHzc+SP2h7r sNZUZFipyy5ZNxGLEfJ0G1d6eb/VLNaABNZMo5uVqXiF5w4Vk98v0QKnZkm1oWO+/y3X Z1VKAeXrLIjxQPnq+sTU07ZQDzx+wIqYgOro0= DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :content-type; b=QnxxGNZJXBEgTujj64HN30xSDbA2yWJig5uwJbHBkGdDnnFWQ7anTTKs2YH3Tl0shk HmB5PpLIFU+tqKKeNYcG+TdPNhCzGhw+j4qEr8rrZckbP5QxpukSmL3mK4eaILMuPzQt 02PctocOT4PyAkAqRE6kHDl9OdJ4uP7SvMVWw= MIME-Version: 1.0 Received: by 10.140.171.18 with SMTP id t18mr3959486rve.95.1236143543336; Tue, 03 Mar 2009 21:12:23 -0800 (PST) In-Reply-To: References: Date: Tue, 3 Mar 2009 21:12:23 -0800 Message-ID: <1c23473f0903032112g7a8ff8eet83f8b1db5f564960@mail.gmail.com> Subject: Re: [FlyRotary] Re: Questions on buying a rotary plane From: David Leonard To: Rotary motors in aircraft Content-Type: multipart/alternative; boundary=000e0cd29d8ccac0d7046444184d --000e0cd29d8ccac0d7046444184d Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: quoted-printable Hey Mike, I have done such a real world direct comparison. We did a race where where were filled tanks before and after to compare fue= l 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. 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. 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 complicate= d > 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 rota= ry > 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 lit= tle > group here. Common perception is that rotaries are gas hogs and we dont d= o > 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 is= nt > the exclusive territory of the rotary. I personally know a guy with a 200= HP > 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 m= ost > seem to do). > > I do totally agree with you on the price of parts. And that was one of m= y > 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 ----- > *From:* Al Gietzen > *To:* Rotary motors in aircraft > *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. T= he > commonly accepted number for a rotary is about .50. Some here seem to do > better, others worse. > > > > 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 wor= se. > 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 w= hy =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 > > --000e0cd29d8ccac0d7046444184d Content-Type: text/html; charset=windows-1252 Content-Transfer-Encoding: quoted-printable Hey Mike,

I have done such a real world direct comparison.=A0
We did a race where where were filled tanks before and after to compare f= uel burn as well as speed.=A0 Scroll down here to see the results:
http://www.rvproject.com/race.htm= l

Bear in mind:
1) the fastest 2 planes were tandem, and had an advant= age.
2) the slowest 2 planes were trying to win the efficiency contest r= ather than the speed contest.

Of the 5 remaining planes, mine was ri= ght in the middle in terms of speed and fuel burn.=A0 All other planes were= 180 or 200 hp lycs with c/s props.=A0 I had the only f.p. prop and my inst= allation cost at least $15k less than any of the others.=A0 Because I was t= he only one able to use MOGAS, my fuel cost were the cheapest (of the non-e= conomy 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.=A0 I fly it hard and put it away= wet.=A0 I have not had an engine or engine systems issue in nearly 200 hrs= .=A0

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. =

Way worth it!

--
David 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= > wrote:
Glad I woke you guys up! :-)
=A0
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 tha= t is=20 not the case. I'm very happy with it. Will be even happier once I get a= ll of the=20 little glitches fixed so=A0I can just fly it.
=A0
=A0I simply wanted to make sure Willia= m=20 understands what he's getting into. What appears to be a fairly straigh= t forward=20 mod is a lot more complicated than it appears and there are potential pitfa= lls=20 that are not necessarily obvious.
=A0
=A0My bad on the misread regarding fue= l=20 efficiency - he=A0was talking about=A0homebuilt aircraft versus factory=20 built planes, not rotaries versus certified engines. I=A0think he's sti= ll way=20 off base here which was why I=A0replied to his post.
=A0
=A0Al, I dont=A0know anyone who actual= ly=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.=A0I know what kind of fuel=20 consumption I got with my Lyc powered RV-6A at cruise=A0and I know there ar= e=20 certainly enough flying Lyc powered RVs to pretty firmly establish a=A0crui= se=20 performance baseline. Since there are more flying rotary powered RVs than o= ther=20 types, seems like we should be able to get at least an idea of how they=20 compare.=A0Lets challenge the rotary RV fliers here to post real cruise=20 performance (altitude, TAS, fuel consumption) and answer the question. Or g= ive=20 me a year and 100 hours and I'll let you know how my RV-4 stacks up aga= inst the=20 -6A for a data point.
=A0
=A0As for your performance against con= ventional=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 ga= s=20 hogs and we dont do anything to accurately document and advertise our=20 performance.
=A0
=A0Mark, I agree that burning Mogas de= finitely=20 makes a big difference economy-wise. But that's a red herring. You coul= d legally=20 burn Mogas in a Lyc/Cont also - just that most guys who are too conservativ= e to=20 choose an auto conversion are also too conservative to burn Mogas. Burning = Mogas=20 isnt the exclusive territory of the rotary.=A0I personally know a guy with = a=20 200HP Lyc in an RV-8 who has burned Mogas exclusively for years. Really wha= t it=20 comes down to is convenience and comfort.=A0Lets be fair,=A0compare apples= =20 to apples, and while we're at it throw in the additional cost and hassl= e of=20 having to pour in 2 stroke oil for your rotary (assuming you do that as mos= t=20 seem to do).
=A0
=A0I do totally agree with you on the = price of=20 parts. And that was one of my huge motivations for going this route. But re= ally=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.
=A0
Mike Wills
RV-4 N144MW
=A0
=A0
----- Original Message -----
From:=20 Al Gietzen=20
Sent: Mond= ay, March 02, 2009 9:51=20 PM
Subject: [FlyRotary] Re: Questions= on=20 buying a rotary plane

=A0I 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

=A0

Mi= ke;

=A0

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= .=A0=20 I see numbers like .43 or .45 bandied about, but I guess no one leans e= nough=20 when flying to get that for fear of burning out a valve =96 or worse.= =A0=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.

=A0

I think in the=20 real world operation the BSFCs are comparable.=A0 I may have a bit lowe= r=20 drag because of smaller cowl; or other factors.

=A0

Al=20 =A0




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