X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from mail-tul01m020-f180.google.com ([209.85.214.180] verified) by logan.com (CommuniGate Pro SMTP 5.4.4) with ESMTPS id 5420491 for flyrotary@lancaironline.net; Tue, 28 Feb 2012 20:15:07 -0500 Received-SPF: pass receiver=logan.com; client-ip=209.85.214.180; envelope-from=keltro@gmail.com Received: by obbwd18 with SMTP id wd18so3258157obb.25 for ; Tue, 28 Feb 2012 17:14:33 -0800 (PST) Return-Path: Received-SPF: pass (google.com: domain of keltro@gmail.com designates 10.60.1.3 as permitted sender) client-ip=10.60.1.3; Authentication-Results: mr.google.com; spf=pass (google.com: domain of keltro@gmail.com designates 10.60.1.3 as permitted sender) smtp.mail=keltro@gmail.com; dkim=pass header.i=keltro@gmail.com Received: from mr.google.com ([10.60.1.3]) by 10.60.1.3 with SMTP id 3mr8357576oei.73.1330478073546 (num_hops = 1); Tue, 28 Feb 2012 17:14:33 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :content-type; bh=udY/zboz4rPPk0YnZriWGzTtx4TSPZ6UrD3wiVvQUOM=; b=AiHKISmLgQyPlSvYeYnM1pL+6XL3IIaIbOdCPUntL/TQGO4Y6Tmmtljuj5Bw/P1myM RjO41c0mIBzdLTw79bYJfZD6xsCGG8zQ85/KGwkualeYB+7K4v8ifZIyi7Nqq8ny/1OT d1D4ddtJoonm79gxR4ADmoMO0I3Vaub6H4ur8= MIME-Version: 1.0 Received: by 10.60.1.3 with SMTP id 3mr7225590oei.73.1330478073498; Tue, 28 Feb 2012 17:14:33 -0800 (PST) Received: by 10.60.40.41 with HTTP; Tue, 28 Feb 2012 17:14:33 -0800 (PST) In-Reply-To: References: Date: Tue, 28 Feb 2012 19:14:33 -0600 Message-ID: Subject: Re: [FlyRotary] Re: Throttle Back Bobble From: Kelly Troyer To: Rotary motors in aircraft Content-Type: multipart/alternative; boundary=e89a8fb1fa56f3cdc404ba101075 --e89a8fb1fa56f3cdc404ba101075 Content-Type: text/plain; charset=ISO-8859-1 Tracy, Does this problem warrant the addition of a thrust bearing in place of the nylon snubber (if this is even economically or physically possible) ??... Kelly Troyer On Thu, Feb 23, 2012 at 7:03 AM, Tracy wrote: > What Lynn said. Most newer cars cut the fuel in that condition and it > DOES eliminate the miss because the engine isn't even running. We don't > want to go there because of the lack of lubrication. > > But most of us pilots were taught to make all throttle changes smoothly > and gradually anyway. Slamming the throttle closed is considered bad form > in an airplane. We do need to deal with the situation where we are going > downhill at the end of a flight and the engine can be windmilling for > significant periods of time. We are in a special situation for two > reasons. First is the lack of apex seal lubrication Lynn mentioned but > also the limitation of the gear drive. The nylon snubber in the drive is > not designed to absorb long term reverse thrust when the engine windmills. > I'm always conscious of maximizing the energy of altitude and descend > with a small amount of power rather than the drag of a windmilling prop. > This maximizes fuel economy, keeps the apex seals happy and keeps the > torque going in the right direction in the gear drive. The number will be > different for different airplanes but for RVs a descent rate of around 300 > fpm at 130 - 140 mph IAS works out well. Plan ahead and watch the Vnav > numbers on your GPS for when it's time to start down. If you have an > autopilot, program it for the appropriate numbers. We don't fly 747s so > throttle control is still up to you. > > Tracy > > Sent from my iPad > > On Feb 22, 2012, at 6:42 PM, Lehanover@aol.com wrote: > > Closed throttle at high revs makes a good fuel burn (idle mixture) > unlikely. The effective compression ratio drops to near zero due to poor > cylinder filling. > > Fuel molecules are very far apart. The stock Renesis maps up to 44 degree > of advance in this situation. The mixture burns very slowly requiring the > added advance (more time to burn). Popping and clicking is still burning > mixture lighting charges in the headers (turbo?) from chambers that didn't > light at all. (Misses). > > In racing engines we didn't use the OMP and only premixed synthetic 2 > cycle oil. So I jetted the idle mix real rich to keep the lube going in > high rev closed throttle moments. > > The sheets of fire out the tail pipe was a crowd pleaser as well as the > explosions on gear changes. It didn't count against our 105 Db sound > limit. > > Lynn E. Hanover > > In a message dated 2/22/2012 4:37:57 P.M. Eastern Standard Time, > cbarber@texasattorney.net writes: > > I had the same issue. I cut the fuel and added a bunch of advance for > high-rev/low-MP operations. Cleaned it right up. > > -- Kelly Troyer Dyke Delta_"Eventually" 13B_RD1C_EC2_EM2 --e89a8fb1fa56f3cdc404ba101075 Content-Type: text/html; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable
=A0=A0 Tracy,
=A0=A0=A0=A0 Does this problem warrant the addition of a thrust bearin= g in place of the nylon snubber (if this is even economically or
physically=A0possible) ??...
=A0
=A0=A0 Kelly Troyer

On Thu, Feb 23, 2012 at 7:03 AM, Tracy <rwstracy@gmail.com&g= t; wrote:
What Lynn said. =A0 Most newer cars cut the fuel in that condition and= it DOES eliminate the miss because the engine isn't even running. =A0 = We don't want to go there because of the lack of lubrication. =A0=A0

But most of us pilots were taught to make all throttle changes smoothl= y and gradually anyway. =A0 Slamming the throttle closed is considered bad = form in an airplane. =A0 We do need to deal with the situation where we are= going downhill at the end of a flight and the engine can be windmilling fo= r significant periods of time. =A0 We are in a special situation for two re= asons. =A0 First is the lack of apex seal lubrication Lynn mentioned but al= so the limitation of the gear drive. =A0The nylon snubber in the drive is n= ot designed to absorb long term reverse thrust when the engine windmills. = =A0 I'm always conscious of maximizing the energy of altitude and desce= nd with a small amount of power rather than the drag of a windmilling prop.= =A0This maximizes fuel economy, keeps the apex seals happy and keeps the t= orque going in the right direction in the gear drive. =A0The number will be= different for different airplanes but for RVs a descent rate of around 300= fpm at 130 - 140 mph IAS works out well. =A0Plan ahead and watch the Vnav = numbers on your GPS for when it's time to start down. =A0 If you have a= n autopilot, program it for the appropriate numbers. =A0 We don't fly 7= 47s so throttle control is still up to you.

Tracy

Sent from my iPad

On Feb 22, 2012, at 6:42 PM, Lehanover@aol.com wrote:

Closed throttle at high revs makes a good fuel burn (idle mixture) unl= ikely. The effective compression ratio drops to near zero due to poor cylin= der filling.
=A0
=A0Fuel molecules are very far apart. The stock Renesis maps up to 44 = degree of advance in this situation. The mixture burns very slowly requirin= g the added advance (more time to burn). Popping and clicking is still burn= ing mixture lighting charges in the headers (turbo?) from chambers that did= n't light at all. (Misses).
=A0
In racing engines we didn't use the OMP and only premixed syntheti= c 2 cycle oil. So I jetted the idle mix real rich to keep the lube going in= high rev closed throttle moments.
=A0
The sheets of fire out the tail pipe was a crowd pleaser as well as th= e explosions on gear changes. It didn't count against our 105 Db=A0 sou= nd limit.
=A0
Lynn E. Hanover
=A0
In a message dated 2/22/2012 4:37:57 P.M. Eastern Standard Time, cbarber@texasatto= rney.net writes:
I had the same issue.=A0 I cut the fuel and added a b= unch of advance for high-rev/low-MP operations.=A0 Cleaned it right up.



--
Kelly Troyer
Dyke Delta_&= quot;Eventually"
13B_RD1C_EC2_EM2
--e89a8fb1fa56f3cdc404ba101075--