X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Tue, 08 May 2012 12:30:01 -0400 Message-ID: X-Original-Return-Path: Received: from cdptpa-omtalb.mail.rr.com ([75.180.132.120] verified) by logan.com (CommuniGate Pro SMTP 5.4.5) with ESMTP id 5527519 for lml@lancaironline.net; Tue, 08 May 2012 09:54:15 -0400 Received-SPF: pass receiver=logan.com; client-ip=75.180.132.120; envelope-from=tednoel@cfl.rr.com X-Original-Return-Path: X-Authority-Analysis: v=2.0 cv=ReYS+iRv c=1 sm=0 a=Juz4b5MAAxrvp7e3l7SsjA==:17 a=zv7pOm2hHFMA:10 a=sWnG8HX0OJUA:10 a=P_ehGkJl0mIA:10 a=05ChyHeVI94A:10 a=Ia-xEzejAAAA:8 a=gKLyQ0ufAAAA:8 a=5Up8faWwAAAA:8 a=oCcaPWc0AAAA:8 a=J_foiKnFVS_r0fnB1rYA:9 a=XLn0Y7wsdnuk6-IUm_gA:7 a=pILNOxqGKmIA:10 a=CVU0O5Kb7MsA:10 a=EzXvWhQp4_cA:10 a=v6MMM96S_sUA:10 a=p-Bui6tgeJ0YlDeV:21 a=D2NwEONQ6TJKGxQp:21 a=4PR2P7QzAAAA:8 a=PPjl_ZywmvigqfJYEW8A:9 a=8lDr7_MfjW5jnzH8eJMA:7 a=_W_S_7VecoQA:10 a=tXsnliwV7b4A:10 a=djSSOgbfo6cA:10 a=wORFUlu_r0fcSA2f:21 a=6s36F_jJbhoyjzrp:21 a=Juz4b5MAAxrvp7e3l7SsjA==:117 X-Cloudmark-Score: 0 X-Originating-IP: 97.101.122.192 Received: from [97.101.122.192] ([97.101.122.192:49494] helo=[192.168.1.2]) by cdptpa-oedge01.mail.rr.com (envelope-from ) (ecelerity 2.2.3.46 r()) with ESMTP id DC/64-07741-26529AF4; Tue, 08 May 2012 13:53:39 +0000 X-Original-Message-ID: <4FA92564.1060802@cfl.rr.com> X-Original-Date: Tue, 08 May 2012 09:53:40 -0400 From: Ted Noel Reply-To: tednoel@cfl.rr.com User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:11.0) Gecko/20120327 Thunderbird/11.0.1 MIME-Version: 1.0 X-Original-To: Lancair Mailing List Subject: Re: [LML] Re: Necessity of A/C in IV-P? References: In-Reply-To: Content-Type: multipart/alternative; boundary="------------030108020404050308000208" This is a multi-part message in MIME format. --------------030108020404050308000208 Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 8bit I've been watching this thread with considerable interest. And all the concerns seem valid. There seem to be three ways to deal with the problem: 1. No A/C. Not a great answer. 2. Detailed structural analysis. Problematic due to cost, and variability in individual builds. 3. Flight testing with a competent test pilot. I think #3 is best since it deals with the variabilities of the installation and creates a hard VNE number. Also, there are a lot of A/C installations flying. This implies a degree of safety. Ted Noel N540TF On 5/8/2012 7:51 AM, Colyn Case wrote: > Hi Bob, > > That would appear to be a huge improvement in that the area of > penetration through the fuselage is greatly reduced. > Congrats on getting your 8 knots back b.t.w. > However, given all previous discussion (e.g. read the "flutter" > article on the main lml page) I personally wouldn't be comfortable > pronouncing it "safe" especially to others, unless I had had the > engineering analysis done on the resulting entire fuselage structure. > > Colyn > > On May 7, 2012, at 7:51 AM, Bob Rickard wrote: > > Charlie K / Colyn > I just did the opposite this winter, and removed the Airflow systems > scoop from my IV-P and engineered a low drag plenum out back. I saw > an 8 knot gain in TAS at FL180. My original system was installed in > 2001 time frame (1^st flight in ’02), so I don’t know if it was the > “reduced drag” version. I’m very aware of the topic of cutting holes > in the fuselage and took great care to overdesign the modification and > have a carbon expert build and install it. There are bids of > reinforcing carbon both inside and outside the fuselage that are cut > well beyond the scoops, which are also made of carbon and hysol’d in. > A couple of pics attached, I’m planning a LOBO paper on it sometime > soon. It works very well, looks fantastic, is light (except for the > fan), and is strong and safe. > Bob R > *From:*Lancair Mailing List [mailto:lml@lancaironline.net]*On Behalf > Of*Charlie Kohler > *Sent:*Friday, May 04, 2012 9:26 AM > *To:*lml@lancaironline.net > *Subject:*[LML] Re: Necessity of A/C in IV-P? > hi Colyn > Yes-it worked out fine. By that- I mean- it was the best you can do. > In the beginning, The pressurized IVs had the cabin intercooler > located on the side of the left lower cowling- with louvers. The > intake air was taken from the engine air cleaner box. Even after > moving the intercooler to the front/left side the air (thanks Don) > into the cabin was measured at 105°on the 70° day. > What I didn't say in the post yesterday was that selecting 11,000 feet > on the controller put an electrical signal to the outflow valve to > open it wide open. You also could use the "dump" switch to open the > valve. That helps a lot. But the big Issue is to shut off that 105° > air from entering the cabin. > I liked the idea of the Airflow design--but I heard stories of > airspeed penalties with the P51 scoop. I asked Bill Genevro if he had > ever considered doing wind tunnel testing.Then they did-- at Ohio > University. They tucked the condenser up closer to the fuselage and > drag reduced drastically. I bought his system. At that time there was > no choice. I did testing later and saw less than three knot change--. > The only holes cut in the fuselage was a pair of 1 inch holes for > freon in and out of the condenser. The beautiful part of it, is that > --it works. Very well! In all regimes. > Charlie K. > See me on the web at > www.Lancair-IV.com > ------------------------------------------------------------------------ > *From:*Colyn Case > > *To:*lml@lancaironline.net > *Sent:*Friday, May 4, 2012 8:08 AM > *Subject:*[LML] Re: Necessity of A/C in IV-P? > Charlie, how did that work out? You eventually added the airflow > systems unit right? > Does that require a hole through the fuselage floor? > On May 3, 2012, at 1:20 PM, Charlie Kohler wrote: > LML gang > In the years before AC was available, I developed a plan for Summer > (hot) flying. On take off I set the controller to 11,000 feet with the > Pressurized air to the cabin OFF. I opened the air valve from the > fresh air from the vertical stabilizer. > I took off and climbed to 11,000 feet . At 10,000 feet I closed the > fresh aHim himir from the vertical stabilizer and gradually selected > the pressurized air to the cabin to the ON position. Then as I > continued to climb I selected the cruise altitude on the > pressurization controller and adjusted the rate knob to 200 feet a > minute descent. The cabin would then descend and level off 1000 feet > above selected altitude. > On the descent into the landing airport-- I set the controller to 1000 > feet above field elevation. > Complicated maybe--but it kept the hot turbocharged air out of the > cabin until it was necessary. > Charlie K. > See me on the web at > www.Lancair-IV.com > ------------------------------------------------------------------------ > *From:*Jim Nordin > > *To:*lml@lancaironline.net > *Sent:*Thursday, May 3, 2012 8:28 AM > *Subject:*[LML] Necessity of A/C in IV-P? > It can be really warn even at 17,000 feet without A/C in an IV-PT. > Why? The bleed air is super warm. Absolutely necessary? Not IMHO. But > a few letdowns from 20k+ and a drip drip drip off the end of your nose > will tell you it’s nice. Or in summer heat in Houston, Phoenix or some > other sauna, it is even better than nice. > Wouldn’t it be good to use that air to air heat exchanger in line with > the bleed air to the cabin?HEAVY. > Jim > ------------------------------------------------------------------------ > *From:*Lancair Mailing List [mailto:lml@lancaironline.net]*On Behalf > Of*Dan & Kari Olsen > *Sent:*Wednesday, May 02, 2012 11:05 AM > *To:*lml@lancaironline.net > *Subject:*[LML] Necessity of A/C in IV-P? > LML Gang, > With all the discussion of structural integrity compromises of the > IV-P fuselage by cutting air conditioning holes, I have a question for > you seasoned IV-P drivers… How necessary is air conditioning in this > aircraft? > I have been flying my 320 for almost 9 years now and certainly would > love to have had it during ground operations on hot summer days with > the green house canopy. However, once moving and at altitude, there > is no need. I realize that the IV-P is going to have warmer air > because of the pressurization but it is also typically flying much > higher (colder ambient) and it doesn’t have the bubble canopy. > So, in normal cross country cruise operations above FL180, do any of > you that don’t have A/C **really** wish that you had it? > I’m early in the building of my IV-P and don’t want to put it in for > several reasons: > ·Weight > ·Potential structural issues > ·Cost > ·One more thing to break down the road > I live in Colorado and will be using this plane as a cross country > traveler with my wife, so comfort is certainly a factor but not at all > costs. One thought is to get one of those cooler-with-ice-and-a-fan > systems to toss in the back seat for those few days that are very hot. > I appreciate your input. > Dan Olsen > Fort Collins, CO > N320DK – 640hrs > IV-P – 10% done > > -- > For archives and unsubhttp://mail.lancaironline.net:81/lists/lml/List.html > > No virus found in this message. > Checked by AVG - www.avg.com > Version: 2012.0.2171 / Virus Database: 2425/4985 - Release Date: 05/08/12 > --------------030108020404050308000208 Content-Type: text/html; charset=windows-1252 Content-Transfer-Encoding: 8bit I've been watching this thread with considerable interest. And all the concerns seem valid. There seem to be three ways to deal with the problem:
1. No A/C.  Not a great answer.
2. Detailed structural analysis. Problematic due to cost, and variability in individual builds.
3. Flight testing with a competent test pilot.

I think #3 is best since it deals with the variabilities of the installation and creates a hard VNE number. Also, there are a lot of A/C installations flying. This implies a degree of safety.

Ted Noel
N540TF

On 5/8/2012 7:51 AM, Colyn Case wrote:
Hi Bob,

That would appear to be a huge improvement in that the area of penetration through the fuselage is greatly reduced.  
Congrats on getting your 8 knots back b.t.w.
However, given all previous discussion (e.g. read the "flutter" article on the main lml page) I personally wouldn't be comfortable pronouncing it "safe" especially to others, unless I had had the engineering analysis done on the resulting entire fuselage structure.  

Colyn

On May 7, 2012, at 7:51 AM, Bob Rickard wrote:

Charlie K / Colyn
 
I just did the opposite this winter, and removed the Airflow systems scoop from my IV-P and engineered a low drag plenum out back.  I saw an 8 knot gain in TAS at FL180.  My original system was installed in 2001 time frame (1st flight in ’02), so I don’t know if it was the “reduced drag” version.   I’m very aware of the topic of cutting holes in the fuselage and took great care to overdesign the modification and have a carbon expert build and install it.  There are bids of reinforcing carbon both inside and outside the fuselage that are cut well beyond the scoops, which are also made of carbon and hysol’d in.   A couple of pics attached, I’m planning a LOBO paper on it sometime soon.  It works very well, looks fantastic, is light (except for the fan), and is strong and safe.
 
Bob R
 
 
From: Lancair Mailing List [mailto:lml@lancaironline.net] On Behalf Of Charlie Kohler
Sent: Friday, May 04, 2012 9:26 AM
To: lml@lancaironline.net
Subject: [LML] Re: Necessity of A/C in IV-P?
 
hi Colyn
Yes-it worked out fine. By that- I mean- it was the best you can do.
In the beginning, The pressurized IVs had the cabin intercooler located on the side of the left lower cowling- with louvers. The intake air was taken from the engine air cleaner box. Even after moving the intercooler to the front/left side the air (thanks Don) into the cabin was measured at 105°on the 70° day.
What I didn't say in the post yesterday was that selecting 11,000 feet on the controller put an electrical signal to the outflow valve to open it wide open. You also could use the "dump" switch to open the valve. That helps a lot. But the big Issue is to shut off that 105° air from entering the cabin.
I liked the idea of the Airflow design--but I heard stories of airspeed penalties with the P51 scoop. I asked Bill Genevro if he had ever considered doing wind tunnel testing.Then they did-- at Ohio University. They tucked the condenser up closer to the fuselage and drag reduced drastically. I bought his system. At that time there was no choice.  I did testing later and saw less than three knot change--. The only holes cut in the fuselage was a pair of 1 inch holes for freon in and out of the condenser. The beautiful part of it, is that --it works. Very well! In all regimes.
 
 
 
Charlie K.
 
See me on the web at
 
 
From: Colyn Case <colyncase@earthlink.net>
To: lml@lancaironline.net 
Sent: Friday, May 4, 2012 8:08 AM
Subject: [LML] Re: Necessity of A/C in IV-P?
 
Charlie, how did that work out?   You eventually added the airflow systems unit right?
Does that require a hole through the fuselage floor?
 
On May 3, 2012, at 1:20 PM, Charlie Kohler wrote:
 
LML gang
In the years before AC was available, I developed a plan for Summer (hot) flying. On take off I set the controller to 11,000 feet with the Pressurized air to the cabin OFF. I opened the air valve from the fresh air from the vertical stabilizer.
 
I took off and climbed to 11,000 feet . At 10,000 feet I closed the fresh aHim himir from the vertical stabilizer and gradually selected the pressurized air to the cabin to the ON position. Then as I continued to climb I selected the cruise altitude on the pressurization controller and adjusted the rate knob to 200 feet a minute descent. The cabin would then descend and level off 1000 feet above selected altitude.
On the descent into the landing airport-- I set the controller to 1000 feet above field elevation.
 
Complicated maybe--but it  kept the hot turbocharged air out of the cabin until it was necessary.
 
Charlie K.
 
See me on the web at
 
 
From: Jim Nordin <panelmaker@earthlink.net>
To: lml@lancaironline.net 
Sent: Thursday, May 3, 2012 8:28 AM
Subject: [LML] Necessity of A/C in IV-P?
 
It can be really warn even at 17,000 feet without A/C in an IV-PT. Why? The bleed air is super warm. Absolutely necessary? Not IMHO. But a few letdowns from 20k+ and a drip drip drip off the end of your nose will tell you it’s nice. Or in summer heat in Houston, Phoenix or some other sauna, it is even better than nice.
Wouldn’t it be good to use that air to air heat exchanger in line with the bleed air to the cabin?HEAVY.
Jim
From: Lancair Mailing List [mailto:lml@lancaironline.net] On Behalf Of Dan & Kari Olsen
Sent: Wednesday, May 02, 2012 11:05 AM
To: lml@lancaironline.net
Subject: [LML] Necessity of A/C in IV-P?
 
LML Gang,
 
With all the discussion of structural integrity compromises of the IV-P fuselage by cutting air conditioning holes, I have a question for you seasoned IV-P drivers…  How necessary is air conditioning in this aircraft?
 
I have been flying my 320 for almost 9 years now and certainly would love to have had it during ground operations on hot summer days with the green house canopy.  However, once moving and at altitude, there is no need.  I realize that the IV-P is going to have warmer air because of the pressurization but it is also typically flying much higher (colder ambient) and it doesn’t have the bubble canopy.
 
So, in normal cross country cruise operations above FL180, do any of you that don’t have A/C *really* wish that you had it?
 
I’m early in the building of my IV-P and don’t want to put it in for several reasons:
·         Weight
·         Potential structural issues
·         Cost
·         One more thing to break down the road
 
I live in Colorado and will be using this plane as a cross country traveler with my wife, so comfort is certainly a factor but not at all costs.  One thought is to get one of those cooler-with-ice-and-a-fan systems to toss in the back seat for those few days that are very hot.
 
I appreciate your input.
 
Dan Olsen
Fort Collins, CO
N320DK – 640hrs
IV-P – 10% done

 

 

 

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For archives and unsub http://mail.lancaironline.net:81/lists/lml/List.html

No virus found in this message.
Checked by AVG - www.avg.com
Version: 2012.0.2171 / Virus Database: 2425/4985 - Release Date: 05/08/12

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