X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from wr-out-0506.google.com ([64.233.184.234] verified) by logan.com (CommuniGate Pro SMTP 5.2.3) with ESMTP id 2978523 for flyrotary@lancaironline.net; Sat, 21 Jun 2008 17:29:30 -0400 Received-SPF: pass receiver=logan.com; client-ip=64.233.184.234; envelope-from=wdleonard@gmail.com Received: by wr-out-0506.google.com with SMTP id c55so1322513wra.11 for ; Sat, 21 Jun 2008 14:28:51 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:received:received:message-id:date:from:to :subject:in-reply-to:mime-version:content-type:references; bh=/preaVung4M/R2H75IL6UYcn7OOzPxcYulpn1u+i7FA=; b=RcVG26YdeTxZnBOkd9IVuemSiRTj01kRA+hZbrRqp8/AOMUJLPP+OG+OfCa5XezgLw MYMmwmfL8lNu82BkkMbi0D981vjYRpEr7NeyjgzcScexMGdSRNb89dRrZ1mgXpQh45ry +MwRSlqEYW2+anUhU5pWMz90fSebkw59WmA/c= DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=message-id:date:from:to:subject:in-reply-to:mime-version :content-type:references; b=fYbiiWgPUR61SryCJsk+1pWRXK+YTy7g6nv0F6+8Xuz1LQKCw+UU+RKtwWitE3KWky BCrNnf2ZcS3qdErcH6TIb8+LNroc4eBH7ZzMxQCCC/5JDqUNbym1gmU4CfC5csMsyRXh DpluiaQ2/bKMqFTi4nXIpBs21v0Nj/wbTOR4I= Received: by 10.90.78.10 with SMTP id a10mr6963463agb.108.1214083731004; Sat, 21 Jun 2008 14:28:51 -0700 (PDT) Received: by 10.90.115.13 with HTTP; Sat, 21 Jun 2008 14:28:50 -0700 (PDT) Message-ID: <1c23473f0806211428n496653abt133abe16d1a4c010@mail.gmail.com> Date: Sat, 21 Jun 2008 14:28:50 -0700 From: "David Leonard" To: "Rotary motors in aircraft" Subject: Re: [FlyRotary] Re: Another Turbo Bites the dust In-Reply-To: MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_Part_17514_27080218.1214083730995" References: ------=_Part_17514_27080218.1214083730995 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Content-Disposition: inline It's amazing how fast 130 hrs goes when you are having fun.:-) I took off the exhaust today and too a look. One of the blades on the turbine wheel is gone, but the axle seems otherwise intact, though it may be off kilter and that is what is causing the resistance when I try to turn it. So I am to sure if the problem was primarily the bearing, or overheat, or overspeed. According to my calculations, turbine speed should have been well within the green area. (way down around 60k RPM - near the bottom of the chart.) One difference with this fligh... I usually run well lean of peak, but this particular leg I was running a little late so I decided to push it up a bit by running a best power setting. I figured I was OK because I was high enough that I was only showing 21" MAP. But the failure happened in descent when I kept best power as I came lower and the engine RPM came up to about 6300 (more exhaust available). Combination of higher than normal EGT's and 'you number is up, turbo'??? Dave Leonard On Sat, Jun 21, 2008 at 1:20 PM, Steve Brooks wrote: > David, > > Sorry to hear about your turbo. Especially sorry since I have one also. > As I recall though, your turbo was an 86-87, which had a somewhat different > design. When I had mine done, the core was an 89-91, which was about $200 > cheaper. Bryan at BNR turbo told me that the 89-91 was much easier to > upgrade was the reason. > > > > I don't know if mine will last any longer though. 130 hours of mostly WOT > doesn't really sound all that bad. It will be interesting to see what > went bad on it. Sounds like it may be the bearings though from the sounds > of it. > > > > Regards, > > Steve Brooks > > > > > > -----Original Message----- > *From:* Rotary motors in aircraft [mailto:flyrotary@lancaironline.net]*On > Behalf Of *David Leonard > *Sent:* Friday, June 20, 2008 11:47 PM > *To:* Rotary motors in aircraft > *Subject:* [FlyRotary] Another Turbo Bites the dust > > > > Today I flew from San Diego to Brownville Texas to attend a formation > flying clinic. After 6 hours of WOT flight I was descending through 5000' > (down from 15.5k) an just a few miles from the airport when I had a sudden > and sickening drop in manifold pressure. The engine was still running > fine, and I had plenty of altitude to make the runway, so I continued on > debating weather or not to flip the turbo oil shutoff switch. I had grown > to respect this turbo so much that I finally decided that I had just blown > out a fitting somewhere in the intake system downstream of the turbo. I > even continued on to a low pass for show rather than just landing. When I > eventually had time to take off the cowl I was dissapointed to find that all > the fitting were in place and that the compressor wheel turns only with > significant resistance. > > So the turbo is dead, and I am out of the formation clinic and will have to > decide tomorrow about flying home with a dead turbo. Will maybe be able to > take a look in the hot side and see what I see. > > This turbo was the TO4 hybrid with a fixed wide open waste gate. It had > 130 hrs of mostly hard duty. Sigh. > > -- > David Leonard > > Turbo Rotary RV-6 N4VY > http://N4VY.RotaryRoster.net > http://RotaryRoster.net > -- David Leonard Turbo Rotary RV-6 N4VY http://N4VY.RotaryRoster.net http://RotaryRoster.net ------=_Part_17514_27080218.1214083730995 Content-Type: text/html; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Content-Disposition: inline It's amazing how fast 130 hrs goes when you are having fun.:-) 

I took off the exhaust today and too a look.  One of the blades on the turbine wheel is gone, but the axle seems otherwise intact, though it may be off kilter and that is what is causing the resistance when I try to turn it.  So I am to sure if the problem was primarily the bearing, or overheat, or overspeed.  According to my calculations, turbine speed should have been well within the green area. (way down around 60k RPM - near the bottom of the chart.)

One difference with this fligh...  I usually run well lean of peak, but this particular leg I was running a little late so I decided to push it up a bit by running a best power setting.  I figured I was OK because I was high enough that I was only showing 21" MAP.  But the failure happened in descent when I kept best power as I came lower and the engine RPM came up to about 6300 (more exhaust available).

Combination of higher than normal EGT's and 'you number is up, turbo'???

Dave Leonard

On Sat, Jun 21, 2008 at 1:20 PM, Steve Brooks <cozy4pilot@gmail.com> wrote:

David,

Sorry to hear about your turbo.   Especially sorry since I have one also.  As I recall though, your turbo was an 86-87, which had a somewhat different design.  When I had mine done, the core was an 89-91, which was about $200 cheaper.  Bryan at BNR turbo told me that the 89-91 was much easier to upgrade was the reason.

 

I don't know if mine will last any longer though. 130 hours of mostly WOT doesn't really sound all that bad.  It will be interesting to see what went bad on it.  Sounds like it may be the bearings though from the sounds of it.

 

Regards,

Steve Brooks

 

 

-----Original Message-----
From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net]On Behalf Of David Leonard
Sent: Friday, June 20, 2008 11:47 PM
To: Rotary motors in aircraft
Subject: [FlyRotary] Another Turbo Bites the dust

 

Today I flew from San Diego to Brownville Texas to attend a formation flying clinic.  After 6 hours of WOT flight I was descending through 5000' (down from 15.5k) an just a few miles from the airport when I had a sudden and sickening drop in manifold pressure.   The engine was still running fine, and I had plenty of altitude to make the runway, so I continued on debating weather or not to flip the turbo oil shutoff switch.  I had grown to respect this turbo so much that I finally decided that I had just blown out a fitting somewhere in the intake system downstream of the turbo.  I even continued on to a low pass for show rather than just landing.  When I eventually had time to take off the cowl I was dissapointed to find that all the fitting were in place and that the compressor wheel turns only with significant resistance.

So the turbo is dead, and I am out of the formation clinic and will have to decide tomorrow about flying home with a dead turbo.  Will maybe be able to take a look in the hot side and see what I see.

This turbo was the TO4 hybrid with a fixed wide open waste gate.  It had 130 hrs of mostly hard duty.  Sigh.

--
David Leonard

Turbo Rotary RV-6 N4VY
http://N4VY.RotaryRoster.net
http://RotaryRoster.net




--
David Leonard

Turbo Rotary RV-6 N4VY
http://N4VY.RotaryRoster.net
http://RotaryRoster.net ------=_Part_17514_27080218.1214083730995--