X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from mail-fx0-f168.google.com ([209.85.220.168] verified) by logan.com (CommuniGate Pro SMTP 5.2.12) with ESMTP id 3527249 for flyrotary@lancaironline.net; Wed, 04 Mar 2009 14:34:08 -0500 Received-SPF: pass receiver=logan.com; client-ip=209.85.220.168; envelope-from=fluffysheap@gmail.com Received: by fxm12 with SMTP id 12so4111310fxm.19 for ; Wed, 04 Mar 2009 11:33:32 -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=03jLFjz9R21GF1CBeb7dd41Z4SLk6+G+grjZQ/DLkH0=; b=PSF+OVhcFdmh62vJ7mK48tSfzN1kP8NjL7vIpA+D5vYKvSW4j+f8F5t/8Tc3yLlhqw wyeTf4L/QR40nALQ1RKaVjyDDH4FTqYqBjV5lNnXpndUhv0KktZ4u+tJVp3gpazR0NLe SudY+Ixwv7I9EAOPBw3adWkN85W/M1AncnXiw= 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=axGehUdSyZ3unga5sowxFnM1qKGZG+ydk4rFV14q5QbQeccrn7qXZo2CSsOT+8tD84 HyZEDO5/xyGadBgHw4SZMg+zLikGTpj+ri3m9ZITOkfwUixDvb5qDSIhhT3xRFgohs+b HZP6mI060k0HkJZ1ZVQUZlB5k9179jnpZxWfQ= MIME-Version: 1.0 Received: by 10.103.172.9 with SMTP id z9mr114032muo.39.1236195211985; Wed, 04 Mar 2009 11:33:31 -0800 (PST) In-Reply-To: References: Date: Wed, 4 Mar 2009 11:33:31 -0800 Message-ID: Subject: Re: [FlyRotary] Re: Questions on buying a rotary plane From: William Wilson To: Rotary motors in aircraft Content-Type: multipart/alternative; boundary=00163641688f7bc31904645020e7 --00163641688f7bc31904645020e7 Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: quoted-printable More car gas is polluted with alcohol nowadays because the distributors don't always want to maintain separate facilities for everything, even wher= e alcohol is not required in fuel, it can be easier for them to just sell it anyway. Of course if you have an airport selling mogas it won't have alcohol but if you self fuel from the local gas station you may find there is alcohol even if your state doesn't mandate it. Would be good to double check. Since the rotary runs perfectly fine in cars with alcohol, so long as your fuel tanks and plumbing can handle it without falling apart, you shouldn't have a problem. Alcohol may have a bit less power but not enough to be unsafe. Important thing for combustion properties is the octane of the fue= l which alcohol does not reduce. Rumors of alcohol causing frozen fuel are just FUD. No one has ever seen i= t happen and the chemistry does not make it particularly likely. Ethanol freezes at -114C! On Wed, Mar 4, 2009 at 5:21 AM, Mark Steitle wrote: > Mike, > > I agree with you that some of the Lycomings can burn mogas, but few > actually do it. I belong to the Lancair list and they are constantly > debating how to (or not to) run their engines so as to not damage them. > Most are just plain scared to run their engines lean of peak where they a= re > able to get close to the "advertised" bsfc. They're willing to burn more > fuel in order to sleep better at night. But the rotary is designed to ru= n > on mogas. So, why not do it? Alcohol and possible vapor lock are the on= ly > issues I know of, and with a properly designed EFI fuel system, vapor loc= k > isn't an issue. As long as they don't start blending alcohol in the fuel= in > my neck of the woods, I'll keep burning mogas and pocketing the differenc= e. > > > You stated, "But really the biggest motivation was to do something a litt= le > different." As for that statement... I couldn't agree more, but how do y= ou > quantify something like that? And I believe that it isn't just different= , > but in a lot of ways the rotary is definitely better. > Mark S. > On Tue, Mar 3, 2009 at 9:55 PM, Mike Wills wrote: > >> Glad I woke you guys up! :-) >> >> While it may appear from my post that I was trying to discourage this gu= y >> 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 complicat= ed >> than it appears and there are potential pitfalls that are not necessaril= y >> obvious. >> >> My bad on the misread regarding fuel efficiency - he was talking >> about homebuilt aircraft versus factory built planes, not rotaries versu= s >> 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 ar= e >> 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 rot= ary >> RV fliers here to post real cruise performance (altitude, TAS, fuel >> consumption) and answer the question. Or give me a year and 100 hours an= d >> 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 li= ttle >> 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 a= n >> auto conversion are also too conservative to burn Mogas. Burning Mogas i= snt >> the exclusive territory of the rotary. I personally know a guy with a 20= 0HP >> Lyc in an RV-8 who has burned Mogas exclusively for years. Really what i= t >> comes down to is convenience and comfort. Lets be fair, compare apples t= o >> 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 i= n >> 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. = The >> 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 wonderin= g if >> you know anybody actually flying a Lyc/Cont and achieving BSFC in the lo= w >> 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 wo= rse. >> I=92ve yet to hear from anyone flying a Velocity like mine with a Lyc wh= o >> 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 hav= e >> a bit lower drag because of smaller cowl; or other factors. >> >> >> >> Al >> >> > --00163641688f7bc31904645020e7 Content-Type: text/html; charset=windows-1252 Content-Transfer-Encoding: quoted-printable More car gas is polluted with alcohol nowadays because the distributors don= 't always want to maintain separate facilities for everything, even whe= re alcohol is not required in fuel, it can be easier for them to just sell = it anyway.=A0 Of course if you have an airport selling mogas it won't h= ave alcohol but if you self fuel from the local gas station you may find th= ere is alcohol even if your state doesn't mandate it.=A0 Would be good = to double check.

Since the rotary runs perfectly fine in cars with alcohol, so long as y= our fuel tanks and plumbing can handle it without falling apart, you should= n't have a problem.=A0 Alcohol may have a bit less power but not enough= to be unsafe.=A0 Important thing for combustion properties is the octane o= f the fuel which alcohol does not reduce.

Rumors of alcohol causing frozen fuel are just FUD.=A0 No one has ever = seen it happen and the chemistry does not make it particularly likely.=A0 E= thanol freezes at -114C!

On Wed, Mar 4, 2= 009 at 5:21 AM, Mark Steitle <msteitle@gmail.com> wrote:
Mike,
=A0
I agree with you that=A0some of the=A0Lycomings can=A0burn mogas,=A0bu= t=A0few actually do it.=A0 I belong to the Lancair list and they are consta= ntly debating how to (or not to) run their engines so as to not damage them= .=A0 Most are just plain scared to run their engines lean of peak where the= y are able to get close to the "advertised"=A0bsfc.=A0 They'r= e willing to burn more fuel in order to sleep better at night.=A0 But the r= otary is designed to run on mogas.=A0 So, why not do it?=A0 Alcohol=A0and p= ossible vapor lock=A0are the only issues I know of, and=A0with a properly d= esigned EFI fuel system, vapor lock isn't an issue.=A0=A0As long as the= y don't start blending alcohol in the fuel=A0in my neck of the woods, I= 'll keep=A0burning mogas and pocketing the difference.=A0
=A0
You stated, "But really the biggest motivation was to do somethin= g a little different."=A0 As for that statement... I couldn't agre= e more, but how do you quantify something like that?=A0 And I believe that = it isn't just different, but in a lot of ways=A0the rotary is definitel= y=A0better.=A0 =A0
Mark S.
On Tue, Mar 3, 2009 at 9:55 PM, Mike Wills <rv-4= mike@cox.net> wrote:
Glad I woke you guys up! :-)
=A0
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 ha= ppier once I get all of the little glitches fixed so=A0I can just fly it.
=A0
=A0I simply wanted to make sure Willia= m understands what he's getting into. What appears to be a fairly strai= ght forward mod is a lot more complicated than it appears and there are pot= ential pitfalls that are not necessarily obvious.
=A0
=A0My bad on the misread regarding fue= l efficiency - he=A0was talking about=A0homebuilt aircraft versus factory b= uilt planes, not rotaries versus certified engines. I=A0think he's stil= l way off base here which was why I=A0replied to his post.
=A0
=A0Al, I dont=A0know anyone who actual= ly KNOWS what BSFC they acheive with their Lyc/Cont. I know that low .40s i= s a published number that is stuck in my head.=A0I know what kind of fuel c= onsumption I got with my Lyc powered RV-6A at cruise=A0and I know there are= certainly enough flying Lyc powered RVs to pretty firmly establish a=A0cru= ise performance baseline. Since there are more flying rotary powered RVs th= an other types, seems like we should be able to get at least an idea of how= they compare.=A0Lets challenge the rotary RV fliers here to post real crui= se performance (altitude, TAS, fuel consumption) and answer the question. O= r 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.
=A0
=A0As for your performance against con= ventional powered Velocities, thats great news. I think thats one of the si= gnificant short comings of our little group here. Common perception is that= rotaries are gas hogs and we dont do anything to accurately document and a= dvertise our performance.
=A0
=A0Mark, I agree that burning Mogas de= finitely 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.= =A0I 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 com= fort.=A0Lets be fair,=A0compare 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).
=A0
=A0I do totally agree with you on the = price of parts. And that was one of my huge motivations for going this rout= e. 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 thi= s year) it's not going to be lost in the sea of belly button RVs that s= how up.
=A0
Mike Wills
RV-4 N144MW
=A0
=A0
----- Original Message -----
From: Al Gietzen
Sent: Monday, March 02, 2009 9:51 PM=
Subject: [FlyRotary] Re: Questions o= n buying a rotary plane

=A0I dont know where you got the= idea that rotaries are more fuel efficient. Lycosaurs/Continentals typical= ly have BSFCs in the low .40s. The commonly accepted number for a rotary is= about .50. Some here seem to do better, others worse.

=A0

Mike;

=A0

I=92m not disagreeing with the= points in your message; but I am wondering if you know anybody actually fl= ying a Lyc/Cont and achieving BSFC in the low 40=92s.=A0 I see numbers like= .43 or .45 bandied about, but I guess no one leans enough when flying to g= et that for fear of burning out a valve =96 or worse.=A0 I=92ve yet to hear= from anyone flying a Velocity<= span style=3D"font-size: 11pt; color: blue; font-family: Verdana;"> like mi= ne 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.

=A0

I think in the real world oper= ation the BSFCs are comparable.=A0 I may have a bit lower drag because of s= maller cowl; or other factors.

=A0

Al =A0

=


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