X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from ms-smtp-05.southeast.rr.com ([24.25.9.104] verified) by logan.com (CommuniGate Pro SMTP 5.1.11) with ESMTP id 2226534 for flyrotary@lancaironline.net; Thu, 02 Aug 2007 05:52:57 -0400 Received-SPF: pass receiver=logan.com; client-ip=24.25.9.104; envelope-from=eanderson@carolina.rr.com Received: from edward2 (cpe-024-074-103-061.carolina.res.rr.com [24.74.103.61]) by ms-smtp-05.southeast.rr.com (8.13.6/8.13.6) with SMTP id l729q5Li021379 for ; Thu, 2 Aug 2007 05:52:05 -0400 (EDT) Message-ID: <000c01c7d4ea$e3512450$2402a8c0@edward2> From: "Ed Anderson" To: "Rotary motors in aircraft" References: Subject: Re: [FlyRotary] Redundant systems Date: Thu, 2 Aug 2007 05:52:49 -0400 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0009_01C7D4C9.5BD43F60" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2900.3138 X-MIMEOLE: Produced By Microsoft MimeOLE V6.00.2900.3138 X-Virus-Scanned: Symantec AntiVirus Scan Engine This is a multi-part message in MIME format. ------=_NextPart_000_0009_01C7D4C9.5BD43F60 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Good recovery from what could been a bad situation, Gaylen. Having made = a 12 mile glide myself, I can emphasize with what must have been going = through your head at the time. Actually, I did not have a circuit breaker failure - but a pin in my = Molex electrical connector carrying power to my coils had become = corroded and pitted to the point it no longer made adequate contact. = This condition possibly from not sizing the pin adequately to carry the = current load. But, whether pin or fuse holder or circuit breaker - all = can fail. However, those details aside, I am in full agreement with you. With = two coils either of which will support flight, I think it wise to have = each coil powered by its own circuit, be it circuit breaker or fuse. = Same applies to our dual fuel pumps also. =20 Again, congratulations on good airmanship. I found that for my Rv-6A = that 87 MPH gave me the minimum sink rate. Had to do a 360 and two hard = "S" turns after my 12 mile glide to make the airport - started out at = 9500 MSL. Ed ----- Original Message -----=20 From: Gaylen Lerohl=20 To: Rotary motors in aircraft=20 Sent: Wednesday, August 01, 2007 11:27 PM Subject: [FlyRotary] Redundant systems A few weeks ago Ed Anderson reported a failed circuit breaker feeding = both coils. He urged that we make our systems redundant where possible, = with separate circuits and circuit protection to each. I second his = plea and share my recent experience as reinforcement. =20 I have about 60 flight hours and about 15 ground hours on my RV8. It = is powered by a 13B with the stock Mazda coils. Tracy recently updated = my EC2 and I installed it Saturday. After a half hour ground run = adjusting the MAP table I shut down and installed the cowl. Taking = Tracy's advice I took off, stayed near the airport and did the Mode 9 = programming at altitudes of 7,000' to 10,000' AGL. I did several = simulated approaches and landings at altitude enjoying the smoother = running engine compared with the previous iteration of the program. = Also spent time among the puffy clouds and cooler air above the haze = layer! After 1.5 hours I began simulating another approach but when I = pulled the power to idle the engine quit. Emergency procedures were = fruitless. Even shutting down the entire system and attempting a = power-up didn't result in an engine start. I was several miles from the = field at about 7,000 AGL. I set up an 85 KT glide, and decided to land = on a runway with a six KT tailwind to avoid flying over a residential = area or over a lake on the approach to an alternate runway. I arrived = over the approach end of the runway on a crosswind leg with 1500' to = lose so I began a tight pattern flying a descending left turn to lose = altitude and position myself for the landing. I lost 500 feet in the = first 180 degrees and about the same in the second 180 degrees. I = rolled out on final high and hot, shut off all the electrics, landed = long but without incident. It all went pretty well other than the fact = I forgot to roll in flaps when I could have used the drag to get me down = sooner. =20 I use fuses for circuit protection so the first troubleshooting step = was to check the fuses - all were OK! I suspected the coils were = involved because the tachometer was reading zero even though the engine = was windmilling. The tach is driven by a signal from the trailing coil. = Using the new diagnostic features, the injectors were clicking OK but = there was no spark. Tracy reminded me of Ed Anderson's post about the = failed breaker feeding both coils. Upon close examination the fuse had = not blown but apparently it has been warm because it had warped. It was = in the fuse holder but somehow was not making contact. Replacing the = fuse cured the problem. =20 I am now a firm advocate of redundancy! I have added a circuit to = power the coils separately and plan to replace the essential bus fuse = panel with circuit breakers. I share this experience to urge those of = you who use a single circuit to power your coils, your fuel pumps, your = EC2 or any other critical systems to modify your wiring so a single = circuit failure doesn't place you in a dangerous position. Mine ran for = about 75 hours. It was just a stroke of good fortune that the failure = occurred while near the airport at an altitude higher than I usually = fly. =20 =20 Here are a couple of data points that may be of interest: The fixed pitch wood prop windmilled at a 100 KT glide, rate = of descent about 1000 FPM. The prop stopped at about 90 KT. Fly safe! Gaylen Lerohl RV8 Alexandria, Minnesota =20 =20 ------=_NextPart_000_0009_01C7D4C9.5BD43F60 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
Good recovery from what could been a bad = situation,=20 Gaylen.  Having made a 12 mile glide myself, I can emphasize with = what must=20 have been going through your head at the time.
 
Actually, I did not have a circuit breaker = failure - but a=20 pin in my Molex electrical connector carrying power to my coils had = become=20 corroded and pitted to the point it no longer made adequate = contact.  This=20 condition possibly from not sizing the pin adequately  to carry the = current=20 load.  But, whether pin or fuse holder or circuit breaker - all can = fail.
 
However, those details aside, I am in=20 full agreement  with you.   With  two = coils either=20 of which will support flight, I think it wise to have each coil powered = by its=20 own circuit,  be it circuit breaker or fuse.  Same applies to = our dual=20 fuel pumps also. 
 
Again, congratulations on good airmanship.  = I found=20 that for my Rv-6A that 87 MPH gave me the minimum sink rate.  Had = to do a=20 360 and two hard "S" turns after my 12 mile glide to make the airport - = started=20 out at 9500 MSL.
 
Ed
----- Original Message -----
From:=20 Gaylen = Lerohl=20
Sent: Wednesday, August 01, = 2007 11:27=20 PM
Subject: [FlyRotary] Redundant=20 systems

A few=20 weeks ago Ed Anderson reported a failed circuit breaker feeding both=20 coils.  He urged that we = make our=20 systems redundant where possible, with separate circuits and circuit=20 protection to each.  I = second his=20 plea and share my recent experience as reinforcement.

 

I have=20 about 60 flight hours and about 15 ground hours on my RV8.  It is powered by a 13B with = the stock=20 Mazda coils. =20 Tracy recently = updated my=20 EC2 and I installed it Saturday. =20 After a half hour ground run adjusting the MAP table I shut = down and=20 installed the cowl.  = Taking=20 Tracy=92s advice I took = off, stayed=20 near the airport and did the Mode 9 programming at altitudes of = 7,000=92 to=20 10,000=92 AGL.  I did = several=20 simulated approaches and landings at altitude enjoying the smoother = running=20 engine compared with the previous iteration of the program.  Also spent time among the = puffy clouds=20 and cooler air above the haze layer! =20 After 1.5 hours I began simulating another approach but when I = pulled=20 the power to idle the engine quit. =20 Emergency procedures were fruitless.  Even shutting down the = entire system=20 and attempting a power-up didn=92t result in an engine start.  I was several miles from the = field at=20 about 7,000 AGL.  I set = up an 85=20 KT glide, and decided to land on a runway with a six KT tailwind to = avoid=20 flying over a residential area or over a lake on the approach to an = alternate=20 runway.  I arrived over = the=20 approach end of the runway on a crosswind leg with 1500=92 to lose so = I began a=20 tight pattern flying a descending left turn to lose altitude and = position=20 myself for the landing.  = I lost=20 500 feet in the first 180 degrees and about the same in the second 180 = degrees.  I rolled out = on final=20 high and hot, shut off all the electrics, landed long but without=20 incident.  It all went = pretty well=20 other than the fact I forgot to roll in flaps when I could have used = the drag=20 to get me down sooner.

 

I use=20 fuses for circuit protection so the first troubleshooting step was to = check=20 the fuses =96 all were OK!  = I=20 suspected the coils were involved because the tachometer was reading = zero even=20 though the engine was windmilling. =20 The tach is driven by a signal from the trailing coil.  Using the new diagnostic=20 features,  the injectors = were=20 clicking OK but there was no spark. =20 Tracy reminded me = of Ed=20 Anderson=92s post about the failed breaker feeding both coils.  Upon close examination the = fuse had=20 not blown but apparently it has been warm because it had warped.  It was in the fuse holder = but somehow=20 was not making contact.  = Replacing=20 the fuse cured the problem.

 

I am now a firm advocate of redundancy!  I have added a circuit to = power the=20 coils separately and plan to replace the essential bus fuse panel with = circuit=20 breakers.  I share this = experience=20 to urge those of you who use a single circuit to power your coils, = your fuel=20 pumps, your EC2 or any other critical systems to modify your = wiring so a=20 single circuit failure doesn=92t place you in a dangerous = position.  Mine ran for about 75 = hours.  It was just a stroke of good = fortune=20 that the failure occurred while near the airport at an altitude higher = than I=20 usually fly.  =

 

Here=20 are a couple of data points that may be of interest:

         =20 The fixed pitch wood prop windmilled at a 100 KT glide, rate of = descent=20 about 1000 FPM.

         =20 The prop stopped at about 90 KT.

 

Fly=20 safe!

Gaylen Lerohl

RV8

Alexandria, = Minnesota

 

 

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