X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from ms-smtp-04.southeast.rr.com ([24.25.9.103] verified) by logan.com (CommuniGate Pro SMTP 5.0.9) with ESMTP id 1123337 for flyrotary@lancaironline.net; Mon, 22 May 2006 11:19:39 -0400 Received-SPF: pass receiver=logan.com; client-ip=24.25.9.103; envelope-from=eanderson@carolina.rr.com Received: from edward2 (cpe-024-074-111-186.carolina.res.rr.com [24.74.111.186]) by ms-smtp-04.southeast.rr.com (8.13.6/8.13.6) with SMTP id k4MFIp5U027805 for ; Mon, 22 May 2006 11:18:53 -0400 (EDT) Message-ID: <000b01c67db3$205076c0$2402a8c0@edward2> From: "Ed Anderson" To: "Rotary motors in aircraft" References: Subject: Re: [FlyRotary] Re: Questions from a potential rotaryphile Date: Mon, 22 May 2006 11:19:31 -0400 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0008_01C67D91.98DD2EC0" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2900.2869 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.2869 X-Virus-Scanned: Symantec AntiVirus Scan Engine This is a multi-part message in MIME format. ------=_NextPart_000_0008_01C67D91.98DD2EC0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Hi Al,=20 Well, as I said I was a bit surprised to have the that attributed to = you. Relating the comments to sole use of Av Fuel, it provides a more = comprehensive context. I find the use of Marvel Mystery oil in the = context of unfouling plugs certainly interesting. I happen to have = purchased a couple of pints to mix with my 2 stroke oil for a different = reason, but will be great if it extended my spark plug replacement = interval. No question use of 100LL in the rotary does lead to plug fouling after = 20-30 hours - at least that is my experience over 300+ hours of rotary = flying. I tried a different plug but could tell no significant = difference. =20 The drop in rpm due to fouling appears have a tendency to occur in any = high power situation - such as during take off - but even during cruise = if running at a high power level. My theory is with WOT the combustion = chamber pressure is higher (due to the denser air/mixture ingested) and = higher pressure makes it tougher for the spark to jump the gap. So if = lead fouling has started to occur, its easier for the electrical energy = to follow the lead deposit than jump the gap. Back off on throttle = thereby reducing manifold pressure resulting in less combustion chamber = pressure makes the job of jumping the gap a bit easier and the spark = plug starts to function normally resulting in power recovery. Normally you do not have both rotors (at least my experience) encounter = this situation simultaneously - unless you have ignored the problem for = a considerable amount of time. Normally its one or the other. However, = I did have both rotors go into SAG mode (once before I fully understood = what was happening) taking off fully loaded. Performance WAS adversely = affected and the pucker factor was there until I realized that even = with both rotors SAGGING, I still had over 500 fpm rate of climb - what = I could only have hoped for flying a Cessna 150. So I just climbed up = to altitude over the airport I had taken off from, pulled back on the = throttle and in approx 3 minutes the SAG situation had cleared up. When SAG occurs I first notice a change in the drone of the engine, = then I find EGT of the afflicted rotor drops about 300F. Rpm will tend = to drop a bit as well - although not as much as in cruise as during take = off. I presume the lower temps are because the unburnt fuel is = causing a cooler exhaust condition in that exhaust port's header. So, anyhow, thanks for setting the matter straight, Al. =20 Ed ----- Original Message -----=20 From: al p wick=20 To: Rotary motors in aircraft=20 Sent: Monday, May 22, 2006 10:43 AM Subject: [FlyRotary] Re: Questions from a potential rotaryphile I'm here Ed. Appreciate your consideration given you were = inadvertently set up. The original post is below. You will note the = paragraph above the section you read talks about negative effect of = EXCLUSIVE use of av fuel. Also described with "this happens every 20 = hours". Original post fwiw: < writes: I'm a bit surprised hearing it came from Al Wick as he was on = this list for a while. I thought he had a better understanding of what = was going on with the rotary. But, you're right a little knowledge = means incomplete knowledge which can be dangerous. Ed ------=_NextPart_000_0008_01C67D91.98DD2EC0 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
Hi Al, 
 
Well, as I said I was a bit = surprised to=20 have the that attributed to you.  Relating the comments to sole =  use=20 of Av Fuel, it provides a more comprehensive context.  I find the = use of=20 Marvel Mystery oil in the context of unfouling plugs certainly=20 interesting.  I happen to have purchased a couple of pints to mix = with my 2=20 stroke oil for a different reason, but will be great if it extended my = spark=20 plug replacement interval.
 
No question use of 100LL in the = rotary does=20 lead to plug fouling after 20-30 hours - at least that is my experience = over=20 300+ hours of rotary flying.  I tried a different plug but could = tell no=20 significant difference.  
 
The drop in rpm due to fouling = appears have=20 a tendency to occur in any high power situation - such as during take = off - but=20 even during cruise if running at a high power level.  My theory is = with WOT=20 the combustion chamber pressure is higher (due to the denser air/mixture = ingested) and higher pressure makes it tougher for the spark to jump the = gap.  So if lead fouling has started to occur, its easier for the=20 electrical energy to follow the lead deposit than jump the gap.  = Back off=20 on throttle thereby reducing manifold pressure resulting in less = combustion=20 chamber pressure makes the job of jumping the gap a bit easier and the = spark=20 plug starts to function normally resulting in power = recovery.
 
Normally you do not have both = rotors (at=20 least my experience) encounter this situation simultaneously - = unless  you=20 have ignored the problem for a considerable amount of time.  = Normally its=20 one or the other.  However, I did have both rotors go into SAG mode = (once=20 before I fully understood what was happening)  taking off = fully=20 loaded.  Performance WAS adversely affected  and the pucker = factor was=20 there until I realized that even with both rotors SAGGING, I still had = over 500=20 fpm rate of climb -  what I could only  have hoped for = flying a=20 Cessna 150.  So I just climbed up to altitude over the airport I = had taken=20 off from, pulled back on the throttle and in approx 3 minutes the SAG = situation=20 had cleared up.
 
When SAG occurs I first notice = a =20 change in the drone of the engine, then I find EGT of the afflicted = rotor drops=20 about 300F. Rpm will tend to drop a bit as well - although not as = much as=20 in cruise as during take off.   I presume the lower temps are=20  because the unburnt fuel is causing a cooler exhaust condition in = that=20 exhaust port's header.
 
So, anyhow,  thanks for = setting the=20 matter straight, Al. 
 
Ed
 
----- Original Message -----
From:=20 al p = wick
Sent: Monday, May 22, 2006 = 10:43 AM
Subject: [FlyRotary] Re: = Questions from a=20 potential rotaryphile

I'm here Ed. Appreciate your consideration given you were = inadvertently=20 set up. The original post is below. You will note the paragraph above = the=20 section you read talks about negative effect of EXCLUSIVE use of av = fuel. Also=20 described with "this happens every 20 hours".
 
Original post fwiw:
 
<<Al- just let me in on the system for the auto engine = logistics-=20 do all the FBO's serve up auto fuel?
 
Auto fuel relatively difficult to find at airports. You can do = web search=20 for all the ones within flying distance. I planned my flight from west = coast=20 to Osh last year. Two different routes. With the cruise range of the = Cozy it=20 was no big deal to buy auto all the way. I recall one location I'd = have to=20 buy a few gallons of aviation fuel.
 
In the past, auto engines would notice slight rpm drop = during cruise=20 if they exclusively burned aviation fuel. Week after week it would = increase.=20 If they ran one tank of auto fuel, it would fix itself until around 10 = avgas=20 tanks later. They now use Marvel Mystery oil of all things, and it = reportedly=20 eliminates all negative effects. Marvel better than 2 other lead=20 scavengers.
 
<<Do the rotory fliers carry chain saw oil mix with them = when going=20 cross country to pour in their tanks after a fill up?
 
Rotary is different issue. Their unusual combustion = chamber=20 requires them to mix 2 cycle oil with each tank. If they don't their=20 compression seals die prematurely. Just like your boat motor mix, I = don't see=20 it as a big deal. In addition, if they use aviation fuel, = they develop=20 power drop on departure and have to replace all their plugs before = next=20 flight. This happens every 20 hours. They don't have solution for = this.
 
<<somebody said they were using jerry cans of auto gas = and=20 bringing them to their hanger to fill up their tanks- is this = right?
 
I find almost all my flying is from home base, returning later = that day.=20 So I fill (3) 5 gallon cans at gas station 1 mile away from airport. = While I'm=20 doing preflight, these drain into my mobile 30 gallon tank. I then = wheel it=20 over to the plane and it takes 20 seconds to fill tank. (compressed = air=20 transfers it very rapidly). Neat trick I learned from motorcycle = buddy. No=20 more inconvenient than taxiing over to HBO to get fuel, way less=20 expensive.
 
If I don't value auto fuel savings, just add some Marvel = each av=20 tank, off I go.
 
-al wick
 
 
On Mon, 22 May 2006 08:06:13 -0400 "Ed Anderson" <eanderson@carolina.rr.com&g= t;=20 writes:

I'm a bit surprised = hearing it came=20 from Al Wick as he was on this list for a while.  I thought = he had=20 a better understanding of what was going on with the = rotary.  But,=20 you're right a little knowledge means incomplete knowledge which = can be=20 dangerous.
 
Ed
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