X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from poplet2.per.eftel.com ([203.24.100.45] verified) by logan.com (CommuniGate Pro SMTP 5.2.16) with ESMTP id 3877433 for flyrotary@lancaironline.net; Wed, 07 Oct 2009 03:31:46 -0400 Received-SPF: none receiver=logan.com; client-ip=203.24.100.45; envelope-from=lendich@aanet.com.au Received: from sv1-1.aanet.com.au (sv1-1.per.aanet.com.au [203.24.100.68]) by poplet2.per.eftel.com (Postfix) with ESMTP id 71117173929 for ; Wed, 7 Oct 2009 15:31:06 +0800 (WST) Received: from ownerf1fc517b8 (203.171.92.134.static.rev.aanet.com.au [203.171.92.134]) by sv1-1.aanet.com.au (Postfix) with SMTP id 85C74BEC020 for ; Wed, 7 Oct 2009 15:31:04 +0800 (WST) Message-ID: From: "George Lendich" To: "Rotary motors in aircraft" References: Subject: Re: [FlyRotary] Balls and springs Date: Wed, 7 Oct 2009 17:31:06 +1000 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0015_01CA4773.F3374FE0" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2900.5843 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.5579 X-Antivirus: avast! (VPS 091006-0, 10/06/2009), Outbound message X-Antivirus-Status: Clean This is a multi-part message in MIME format. ------=_NextPart_000_0015_01CA4773.F3374FE0 Content-Type: text/plain; charset="Windows-1252" Content-Transfer-Encoding: quoted-printable Lynn, That's a good write-up, as usual - I would like to make the comment that = the 16X has narrow rotors because of that problem of losing heat in such = a large rotor area, resulting in incomplete burn. This supports your = comments I believe. George (down under) OK here you go...... The rotary has problems with unburned hydrocarbons = at all RPMs. The reason is the area of cooled combustion chamber = available to the fuel air charge. The mixture tends to condense back = into droplets and that reduces the area of the total number of gasoline = molecules available to latch on to an oxygen molecule so more than we = would like never combine with oxygen and do not get burned in the = chamber, but get excited by the heat of combustion and mate up further = town stream about where your EGT probe is installed. Many other problems = can be traced right to this same problem. No starts due to low cranking = speed is one. No heat of compression equals no excitement and no = combining and no start.=20 You can see Mazda working to reduce this problem by getting the engine = to warm quickly, and thus reduce the fleet HC output and be allowed to = sell them in California. First you see that god awful stock thermostat, = with its two plungers and plugs. When cold the lower hole is open and = the upper hole is closed. So as the engine starts up cold, water can = circulate inside the engine only. So, the engine warms uniformly and = when at full operating temperature the upper hole opens to the cooling = system and the lower hole is closed off.=20 That is the water trick. The oil trick is the balls and springs in the = crank. If the engine is started and left to idle, the balls remain = seated and no oil sprays into the rotors to cool them off. From a cold = start they want the rotors to heat up ASAP to reduce the HC. So if you = drive away, you are heating the rotors with the combustion process, and = the balls unseating from RPM changes makes little difference. If left to = idle for long periods, only bearing spill will enter the rotors to cool = them, but that is plenty. There have been and are other schemes involved as well but the ideas = are the same. Rapid heating of the chamber on startup.=20 So limiting cooling during warmup is to reduce HC and improved mileage = due to the lower viscosity and less drag of warmed oil. Simple.=20 To meter the amount of oil there is a specific sized hole in a bolt = head that holds the springs and balls in the gallery in the crank. The = down side of removing the balls and springs is that the rather small oil = pump cannot maintain enough oil pressure to keep the idiot light out at = hot idle. The missing balls produce 2 big oil leaks in the crank. Not a = thing to worry about, because the bearings are huge for the loads = involved, but it worries people to see the light on, or the gage below = 20 pounds on a hot day.=20 Racers increase the oil pressure in order to move heated oil off of = the bearings quickly to prevent melting the soft grey stuff on the = bearings. Ay higher revs the stock pump has enough output to do this. = The higher oil pressure (say 100 pounds instead of the stock 71 pounds) = then causes the two cooling jets in the crank to put out a bit too much = oil to the rotors. This results in plenty of cooling of course, but it = also adds to the foaming of the oil that then drops back into the sump = through that hole in the center iron. Foamed oil has trapped air mixed = up in it, and air is an insulator, so the effect is that oil coolers = start to act smaller than they are. So if you have jacked up the oil = pressure on an early engine, then you probably need to add the Weber air = correction jet to replace the ball and spring. The amount of oil = supplied is reduced with RPM when you scream the engine because of the = centrifugal load of the oil column being pushed into the crank. So the = FD or twin turbo engines used 115 pounds of oil pressure. So at modest = speeds you are putting a bunch of oil through the rotors. I suspect, but do not know if the later engines have smaller jets to = account for the higher oil pressure. Typical jets are.220MM for turbo = engines or .200 MM for NA engines. (Racing Beat). I use .180MM and 100 = pounds of pressure but I have very good oil cooling. Oil temps above 160 = degrees cost HP according to Daryl Drummond who built our first race = engines. Also all of the star Mazda and Formula Mazda series engines.=20 At airplane RPM there is just no problem with rotor cooling that can = be attributed to the balls and springs or lack thereof. Oil cooling is a = function of cooler size and airflow. Some improvement might be seen if a = straight weight oil is used over a multi grade to avoid some of the = foaming. Or if a racing oil is used that has anti foaming agents and = additional anti scuffing agents. Mistral found that to be the case as = they used airplane oil at first, and kept overheating the oil. It was an = airplane after all.=20 Although it reduces power, the hotter rotor would produce better = mileage due to better fuel burn. So if you lean it way out anyway, it is = off of full power, so it might be worth some investigation, since there = is much whining about fuel consumption in rotaries.=20 Lynn E. Hanover =20 -------------------------------------------------------------------------= ----- -- Homepage: http://www.flyrotary.com/ Archive and UnSub: = http://mail.lancaironline.net:81/lists/flyrotary/List.html ------=_NextPart_000_0015_01CA4773.F3374FE0 Content-Type: text/html; charset="Windows-1252" Content-Transfer-Encoding: quoted-printable
 
Lynn,
That's a good write-up, as usual - I would like to make the comment = that=20 the 16X has narrow rotors because of that problem of losing heat in such = a large=20 rotor area, resulting in incomplete burn. This supports your comments I=20 believe.
George (down under)
 
 
OK here you go...... The rotary has problems with unburned = hydrocarbons at=20 all RPMs. The reason is the area of cooled combustion chamber available = to the=20 fuel air charge. The mixture tends to condense back into droplets and = that=20 reduces the area of the total number of gasoline molecules available to = latch on=20 to an oxygen molecule so more than we would like never combine with = oxygen and=20 do not get burned in the chamber, but get excited by the heat of = combustion and=20 mate up further town stream about where your EGT probe is installed. = Many other=20 problems can be traced right to this same problem. No starts due to low = cranking=20 speed is one. No heat of compression equals no excitement and no = combining and=20 no start.
 
You can see Mazda working to reduce this problem by getting the = engine to=20 warm quickly, and thus reduce the fleet HC output and be allowed to = sell them=20 in California. First you see that god awful stock thermostat, with its = two=20 plungers and plugs. When cold the lower  hole is open and the = upper hole=20 is closed. So as the engine starts up cold, water can circulate inside = the=20 engine only. So, the engine warms uniformly and when at full operating = temperature the upper hole opens to the cooling system and the lower = hole is=20 closed off.
 
That is the water trick. The oil trick is the balls and springs = in the=20 crank. If the engine is started and left to idle, the balls remain = seated and=20 no oil sprays into the rotors to cool them off. From a cold start they = want=20 the rotors to heat up ASAP to reduce the HC. So if you drive away, you = are=20 heating the rotors with the combustion process, and the balls = unseating from=20 RPM changes makes little difference. If left to idle for long periods, = only=20 bearing spill will enter the rotors to cool them, but that is = plenty.
 
There have been and are other schemes involved as well but the = ideas are=20 the same. Rapid heating of the chamber on startup.
 
So limiting cooling during warmup is to reduce HC and improved = mileage=20 due to the lower viscosity and less drag of warmed oil. Simple.
 
To meter the amount of oil there is a specific sized hole in a = bolt head=20 that holds the springs and balls in the gallery in the crank. The down = side of=20 removing the balls and springs is that the rather small oil pump = cannot=20 maintain enough oil pressure to keep the idiot light out at hot idle. = The=20 missing balls produce 2 big oil leaks in the crank. Not a thing to = worry=20 about, because the bearings are huge for the loads involved, but it = worries=20 people to see the light on, or the gage below 20 pounds on a hot day. =
 
Racers increase the oil pressure in order to move heated oil off = of the=20 bearings quickly to prevent melting the soft grey stuff on the = bearings. Ay=20 higher revs the stock pump has enough output to do this. The higher = oil=20 pressure (say 100 pounds instead of the stock 71 pounds) then causes = the two=20 cooling jets in the crank to put out a bit too much oil to the rotors. = This=20 results in plenty of cooling of course, but it also adds to the = foaming of the=20 oil that then drops back into the sump through that hole in the center = iron.=20 Foamed oil has trapped air mixed up in it, and air is an insulator, so = the=20 effect is that oil coolers start to act smaller than they are. So if = you have=20 jacked up the oil pressure on an early engine, then you probably need = to add=20 the Weber air correction jet to replace the ball and spring. The = amount of oil=20 supplied is reduced with RPM when you scream the engine because of the = centrifugal load of the oil column being pushed into the crank. So the = FD or=20 twin turbo engines used 115 pounds of oil pressure. So at modest = speeds you=20 are putting a bunch of oil through the rotors.
 
 I suspect, but do not know if the later engines have = smaller jets=20 to account for the higher oil pressure. Typical jets are.220MM for = turbo=20 engines or .200 MM for NA engines. (Racing Beat). I use .180MM and 100 = pounds=20 of pressure but I have very good oil cooling. Oil temps above 160 = degrees=20 cost HP according to Daryl Drummond who built our first race engines. = Also all=20 of the star Mazda and Formula Mazda series engines.
 
At airplane RPM there is just no problem with rotor cooling that = can be=20 attributed to the balls and springs or lack thereof. Oil cooling is a = function=20 of cooler size and airflow. Some improvement might be seen if a = straight=20 weight oil is used over a multi grade to avoid some of the foaming. Or = if a=20 racing oil is used that has anti foaming agents and additional anti = scuffing=20 agents. Mistral found that to be the case as they used airplane oil at = first,=20 and kept overheating the oil. It was an airplane after all.
 
Although it reduces power, the hotter rotor would produce better = mileage=20 due to better fuel burn. So if you lean it way out anyway, it is off = of full=20 power, so it might be worth some investigation, since there is much = whining=20 about fuel consumption in rotaries. 
 
Lynn E. Hanover   

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