X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Wed, 23 Apr 2014 18:04:57 -0400 Message-ID: X-Original-Return-Path: Received: from ndmsnpf03.ndc.nasa.gov ([198.117.0.123] verified) by logan.com (CommuniGate Pro SMTP 6.0.9e) with ESMTP id 6844435 for lml@lancaironline.net; Wed, 23 Apr 2014 17:27:15 -0400 Received-SPF: pass receiver=logan.com; client-ip=198.117.0.123; envelope-from=valin.b.thorn@nasa.gov Received: from ndmsppt104.ndc.nasa.gov (ndmsppt104.ndc.nasa.gov [198.117.0.69]) by ndmsnpf03.ndc.nasa.gov (Postfix) with ESMTP id 03A042D8076 for ; Wed, 23 Apr 2014 16:26:41 -0500 (CDT) Received: from NDMSCHT116.ndc.nasa.gov (ndmscht116-pub.ndc.nasa.gov [198.117.0.216]) by ndmsppt104.ndc.nasa.gov (8.14.5/8.14.5) with ESMTP id s3NLQePu007619 for ; Wed, 23 Apr 2014 16:26:40 -0500 Received: from NDMSMBX402.ndc.nasa.gov ([169.254.2.176]) by NDMSCHT116.ndc.nasa.gov ([198.117.0.216]) with mapi id 14.03.0174.001; Wed, 23 Apr 2014 16:26:40 -0500 From: "Thorn, Valin B. (JSC-VA411)" X-Original-To: Lancair Mailing List X-Original-CC: "Thorn, Valin B. (JSC-VA411)" Subject: RE: [LML] Re: Hartzell Prop Governor Low RPM Capability Thread-Topic: [LML] Re: Hartzell Prop Governor Low RPM Capability Thread-Index: AQHPXw+LCOifzJzzTUGCiHR44oHXZZsfndqA X-Original-Date: Wed, 23 Apr 2014 21:26:40 +0000 X-Original-Message-ID: <0705A91F9164914998F23A2F0BB661A91412F6@NDMSMBX402.ndc.nasa.gov> References: In-Reply-To: Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-originating-ip: [66.35.45.94] Content-Type: multipart/alternative; boundary="_000_0705A91F9164914998F23A2F0BB661A91412F6NDMSMBX402ndcnasa_" MIME-Version: 1.0 X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:5.11.96,1.0.14,0.0.0000 definitions=2014-04-23_04:2014-04-23,2014-04-23,1970-01-01 signatures=0 --_000_0705A91F9164914998F23A2F0BB661A91412F6NDMSMBX402ndcnasa_ Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable Hi Doug, We installed Adam's closing inboard gear door system for general takeoff & = landing performance and handling improvements and not really for improved e= ngine out gear down glide. As you said, in an engine out emergency, the ge= ar are likely coming down just before landing. I don't know if by now Adam has put together any numbers on the benefits of= closing the inboard gear doors when the gear are down. We added the syste= m years ago based on these likely benefits: * Better Lift/Drag ratio in landing and takeoff configuration (litt= le wings, big openings in bottom) * Reduced gust disturbance effects in gear down config * Reduced wear on inboard gear doors (noticed they take a bit of pu= nishment even when people are taxiing, from the propeller slip stream) * Reduced contamination thrown up in wheel wells Won't know if the system is worth the added complexity until flying. Adam = has one of the more elegant solutions, though, with a hydraulics manifold a= nd cross over valve to handle the sequencing. He also reports that it's a = lot quieter in the cockpit with the gear down with the inboard doors closed= . On the hydraulic system, from reading Chris Zavatson's excellent report on = the system, Legacy airplanes have various configurations of the pump depend= ing on when the kit was shipped. We have a pre-2005 kit which is a hybrid = between what was used in 320/360's and the Legacy's baseline system today. = I think William Ford has the same configuration and so what he's experienc= ing is likely what we'll experience. Do you have a post-2005 Legacy kit? = I'm probably going to just change out the spool for a symmetric one based o= n Chris' recommendation. Thanks. Appreciate your thoughts on all this. Valin From: Lancair Mailing List [mailto:lml@lancaironline.net] On Behalf Of Denn= is Johnson Sent: Wednesday, April 23, 2014 10:18 AM To: lml@lancaironline.net Subject: [LML] Re: Hartzell Prop Governor Low RPM Capability Hi Valin, I'm not sure why you're concerned about the extra drag from the main landin= g gear doors. When I practice simulated engine out landings, I don't lower= the gear until it's clear that I'm going to land too long if I don't do so= mething to slow down. If I had a real engine failure and wasn't going to m= ake it to a runway, I'd probably leave the gear up. Regarding the need to cycle the dump valve to get the landing gear up or do= wn, in 700 hours in my Legacy, I've never had a problem that required openi= ng the dump valve. My guess is that it's a rare condition, possibly limite= d to a small number of Legacies, most likely due to a problem with the hydr= aulic power pack. Based on my experience, I wouldn't add more time, money,= and parts count to solve a problem that's unlikely and, if it does occur, = has a simple immediate fix. Best, Dennis ----- Original Message ----- From: Thorn, Valin B. (JSC-VA411) To: lml@lancaironline.net Sent: Tuesday, April 22, 2014 12:03 PM Subject: [LML] Re: Hartzell Prop Governor Low RPM Capability Thanks John. Makes it clear why one of the Legacy instructors was quoted a= s saying, "With the engine out, the Legacy comes down like a greased Buick"= - I guess specifically talking about with the gear down. We have Adam Molny's closing inboard landing gear door system which should = help with the gear down drag a lot. Adam, if you see this, do you have eng= ine off sink rate numbers with your gear down and inboard doors closed you = can share for comparison? Thanks, Valin Thorn Legacy Project Boulder, Colorado --_000_0705A91F9164914998F23A2F0BB661A91412F6NDMSMBX402ndcnasa_ Content-Type: text/html; charset="us-ascii" Content-Transfer-Encoding: quoted-printable

Hi Doug,

 <= /span>

We installed Adam&= #8217;s closing inboard gear door system for general takeoff & landing = performance and handling improvements and not really for improved engine out gear down glide.  As you said, in an engine out emergency,= the gear are likely coming down just before landing. 

 <= /span>

I don’t know= if by now Adam has put together any numbers on the benefits of closing the= inboard gear doors when the gear are down.  We added the system years ago based on these likely benefits:

 <= /span>

·      = ;   Better Lif= t/Drag ratio in landing and takeoff configuration (little wings, big openin= gs in bottom)

·      = ;   Reduced gu= st disturbance effects in gear down config

·      = ;   Reduced we= ar on inboard gear doors (noticed they take a bit of punishment even when p= eople are taxiing, from the propeller slip stream)

·      = ;   Reduced co= ntamination thrown up in wheel wells

 <= /span>

Won’t know i= f the system is worth the added complexity until flying.  Adam has one= of the more elegant solutions, though, with a hydraulics manifold and cross over valve to handle the sequencing.  He also reports that = it’s a lot quieter in the cockpit with the gear down with the inboard= doors closed.

 <= /span>

On the hydraulic s= ystem, from reading Chris Zavatson’s excellent report on the system, = Legacy airplanes have various configurations of the pump depending on when the kit was shipped.  We have a pre-2005 kit which is a hybri= d between what was used in 320/360’s and the Legacy’s baseline = system today.  I think William Ford has the same configuration and so = what he’s experiencing is likely what we’ll experience.  Do you have a post-2005 Legacy kit?  I’m probably going to just= change out the spool for a symmetric one based on Chris’ recommendat= ion.

 <= /span>

Thanks.  Appr= eciate your thoughts on all this.

 <= /span>

Valin

 

 <= /span>

From: Lancair = Mailing List [mailto:lml@lancaironline.net] On Behalf Of Dennis Johnson
Sent: Wednesday, April 23, 2014 10:18 AM
To: lml@lancaironline.net
Subject: [LML] Re: Hartzell Prop Governor Low RPM Capability

 

Hi Valin,

 

I'm not sure why you're concerned ab= out the extra drag from the main landing gear doors.  When I practice = simulated engine out landings, I don't lower the gear until it's clear that I'm going to land too long if I don't do something to slow down= .  If I had a real engine failure and wasn't going to make it to a run= way, I'd probably leave the gear up. 

 

Regarding the need to cycle the dump= valve to get the landing gear up or down, in 700 hours in my Legacy, I've = never had a problem that required opening the dump valve.  My guess is that it's a rare condition, possibly limited to a small number= of Legacies, most likely due to a problem with the hydraulic power pa= ck.  Based on my experience, I wouldn't add more time, money, and part= s count to solve a problem that's unlikely and, if it does occur, has a simple immediate fix. 

 

Best,

Dennis 

----- Original Message -----

Sent: Tuesday, A= pril 22, 2014 12:03 PM

Subject: [LML] R= e: Hartzell Prop Governor Low RPM Capability

 

Thanks John. = Makes it clear why one of the Legacy instructors was quoted as saying, = 220;With the engine out, the Legacy comes down like a greased Buick” – I guess specifically talking about with the gear down.  =

 <= /span>

We have Adam Molny= ’s closing inboard landing gear door system which should help with th= e gear down drag a lot.  Adam, if you see this, do you have engine off sink rate numbers with your gear down and inboard doors closed you can= share for comparison?

 <= /span>

Thanks,=

 <= /span>

Valin Thorn

Legacy Project

Boulder, Colorado<= o:p>

 <= /span>

 

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