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[166.248.77.63]) by mx.google.com with ESMTPS id bk18sm19568200vdb.18.2012.03.04.05.45.01 (version=TLSv1/SSLv3 cipher=OTHER); Sun, 04 Mar 2012 05:45:03 -0800 (PST) Subject: Re: [FlyRotary] Re: Throttle Back Bobble References: From: Tracy Content-Type: multipart/alternative; boundary=Apple-Mail-26-374185983 X-Mailer: iPad Mail (8F191) In-Reply-To: Message-Id: Date: Sun, 4 Mar 2012 08:45:01 -0500 To: Rotary motors in aircraft Content-Transfer-Encoding: 7bit Mime-Version: 1.0 (iPad Mail 8F191) --Apple-Mail-26-374185983 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset=us-ascii Got it OK Brian. Should get it done by tomorrow. Tracy Sent from my iPad On Mar 2, 2012, at 10:10 AM, bktrub@aol.com wrote: > Tracy, did you receive my ec2 yet? I just want to make sure the post offic= e is not using it as a paperweight. > Thanks, > Brian trubee >=20 > Sent from my Verizon Wireless Phone >=20 > ----- Reply message ----- > From: "Tracy" > To: "Rotary motors in aircraft" > Subject: [FlyRotary] Re: Throttle Back Bobble > Date: Thu, Mar 1, 2012 5:42 am >=20 >=20 > I don't think so but that's just my opinion. No one has had any trouble w= ith the snubber so far. It normally is not under load except during start u= p because the input gear is hydraulically loaded against the thrust bearing b= y engine oil pressure. I do not know how much reverse thrust it would take= to overcome that pressure. Just cautioning against going to idle and point= ing the plane steeply down hill for the reasons already stated. >=20 > Tracy >=20 > Sent from my iPad >=20 > On Feb 28, 2012, at 8:14 PM, Kelly Troyer wrote: >=20 >> Tracy, >> Does this problem warrant the addition of a thrust bearing in place o= f the nylon snubber (if this is even economically or >> physically possible) ??... >> =20 >> Kelly Troyer >>=20 >> 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 D= OES eliminate the miss because the engine isn't even running. We don't wan= t to go there because of the lack of lubrication. =20 >>=20 >> But most of us pilots were taught to make all throttle changes smoothly a= nd gradually anyway. Slamming the throttle closed is considered bad form i= n an airplane. We do need to deal with the situation where we are going do= wnhill at the end of a flight and the engine can be windmilling for signific= ant periods of time. We are in a special situation for two reasons. Firs= t is the lack of apex seal lubrication Lynn mentioned but also the limitatio= n of the gear drive. The nylon snubber in the drive is not designed to abso= rb long term reverse thrust when the engine windmills. I'm always consciou= s of maximizing the energy of altitude and descend with a small amount of po= wer 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 directi= on in the gear drive. The number will be different for different airplanes b= ut for RVs a descent rate of around 300 fpm at 130 - 140 mph IAS works out w= ell. Plan ahead and watch the Vnav numbers on your GPS for when it's time t= o start down. If you have an autopilot, program it for the appropriate num= bers. We don't fly 747s so throttle control is still up to you. >>=20 >> Tracy >>=20 >> Sent from my iPad >>=20 >> On Feb 22, 2012, at 6:42 PM, Lehanover@aol.com wrote: >>=20 >>> Closed throttle at high revs makes a good fuel burn (idle mixture) unlik= ely. The effective compression ratio drops to near zero due to poor cylinder= filling. >>> =20 >>> Fuel molecules are very far apart. The stock Renesis maps up to 44 degr= ee of advance in this situation. The mixture burns very slowly requiring the= added advance (more time to burn). Popping and clicking is still burning mi= xture lighting charges in the headers (turbo?) from chambers that didn't lig= ht at all. (Misses). >>> =20 >>> In racing engines we didn't use the OMP and only premixed synthetic 2 cy= cle oil. So I jetted the idle mix real rich to keep the lube going in high r= ev closed throttle moments. >>> =20 >>> The sheets of fire out the tail pipe was a crowd pleaser as well as the e= xplosions on gear changes. It didn't count against our 105 Db sound limit. >>> =20 >>> Lynn E. Hanover >>> =20 >>> 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 h= igh-rev/low-MP operations. Cleaned it right up. >>=20 >>=20 >>=20 >> --=20 >> Kelly Troyer >> Dyke Delta_"Eventually" >> 13B_RD1C_EC2_EM2 --Apple-Mail-26-374185983 Content-Transfer-Encoding: quoted-printable Content-Type: text/html; charset=utf-8
Got it OK Brian.   Should get it d= one by tomorrow.

Tracy

Sent from my iPad

On Mar 2, 2012, at 10:10 AM, bk= trub@aol.com <bktrub@aol.com>= ; wrote:

Tracy, did y= ou receive my ec2 yet? I just want to make sure the post office is not using= it as a paperweight.
Thanks,
Brian trubee

Sent from my Verizon= Wireless Phone

----- Reply message= -----
From: "Tracy" <rwstracy@g= mail.com>
To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
Subject: [= FlyRotary] Re: Throttle Back Bobble
Date: Thu, Mar 1, 2012 5:42 am

I don't think so but that's just my opinion.   No one h= as had any trouble with the snubber so far.  It normally is not under l= oad except during start up because the input gear is hydraulically loaded ag= ainst the thrust bearing by engine oil pressure.   I do not know how mu= ch reverse thrust it would take to overcome that pressure.  Just cautio= ning against going to idle and pointing the plane steeply down hill for the r= easons already stated.

Tracy

Sent from my iP= ad

On Feb 28, 2012, at 8:14 PM, Kelly Troyer <keltro@gmail.com<= /a>> wrote:

   Tracy,
     Does this problem warrant the addition of a th= rust bearing in place of the nylon snubber (if this is even economically or<= /div>
physically possible) ??...
 
   Kelly Troyer

On Thu, Feb 23, 2012 at 7:03 AM, Tracy <rwstracy@gmail.com> wrote:
What Lynn said.   Most newer cars cut the fuel in that condition a= nd it DOES eliminate the miss because the engine isn't even running.   W= e 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 a= re going downhill at the end of a flight and the engine can be windmilling f= or significant periods of time.   We are in a special situation for two= reasons.   First is the lack of apex seal lubrication Lynn mentioned b= ut also the limitation of the gear drive.  The nylon snubber in the dri= ve is not designed to absorb long term reverse thrust when the engine windmi= lls.   I'm always conscious of maximizing the energy of altitude and de= scend with a small amount of power rather than the drag of a windmilling pro= p.  This maximizes fuel economy, keeps the apex seals happy and keeps t= he torque going in the right direction in the gear drive.  The number w= ill be different for different airplanes but for RVs a descent rate of aroun= d 300 fpm at 130 - 140 mph IAS works out well.  Plan ahead and watch th= e Vnav numbers on your GPS for when it's time to start down.   If you h= ave an autopilot, program it for the appropriate numbers.   We don't fl= y 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) unli= kely. The effective compression ratio drops to near zero due to poor cylinde= r filling.
 
 Fuel molecules are very far apart. The stock Renesis maps up to 4= 4 degree of advance in this situation. The mixture burns very slowly requiri= ng the added advance (more time to burn). Popping and clicking is still burn= ing 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 c= ycle oil. So I jetted the idle mix real rich to keep the lube going in high r= ev 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 l= imit.
 
Lynn E. Hanover
 
In a message dated 2/22/2012 4:37:57 P.M. Eastern Standard Time, c= barber@texasattorney.net writes:
I had the same issue.  I cut the fuel and added a bu= nch of advance for high-rev/low-MP operations.  Cleaned it right up.



--
Kelly Troyer
Dyke Delta_"Ev= entually"
13B_RD1C_EC2_EM2
= --Apple-Mail-26-374185983--