X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Wed, 18 Dec 2013 08:46:57 -0500 Message-ID: X-Original-Return-Path: Received: from nk11p08mm-asmtp001.mac.com ([17.158.58.246] verified) by logan.com (CommuniGate Pro SMTP 6.0.7) with ESMTP id 6643652 for lml@lancaironline.net; Wed, 18 Dec 2013 08:39:48 -0500 Received-SPF: pass receiver=logan.com; client-ip=17.158.58.246; envelope-from=gw5@me.com Received: from [192.168.0.11] (cpe-071-077-249-052.ec.res.rr.com [71.77.249.52]) by nk11p08mm-asmtp001.mac.com (Oracle Communications Messaging Server 7u4-27.08(7.0.4.27.7) 64bit (built Aug 22 2013)) with ESMTPSA id <0MY0001EE8LCGP90@nk11p08mm-asmtp001.mac.com> for lml@lancaironline.net; Wed, 18 Dec 2013 13:39:14 +0000 (GMT) X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:5.11.87,1.0.14,0.0.0000 definitions=2013-12-18_05:2013-12-18,2013-12-18,1970-01-01 signatures=0 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 spamscore=0 suspectscore=0 phishscore=0 adultscore=0 bulkscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=7.0.1-1308280000 definitions=main-1312180067 From: George Wehrung Content-type: multipart/alternative; boundary="Apple-Mail=_E584E6C0-21D3-4408-BB8D-9085E610AC36" X-Original-Message-id: <3101A6C1-97CE-4701-A496-35B757617DDC@me.com> MIME-version: 1.0 (Mac OS X Mail 7.0 \(1822\)) Subject: Re: [LML] Debunking myth of flying fast into headwind X-Original-Date: Wed, 18 Dec 2013 08:39:06 -0500 References: X-Original-To: Lancair Mailing List In-reply-to: X-Mailer: Apple Mail (2.1822) --Apple-Mail=_E584E6C0-21D3-4408-BB8D-9085E610AC36 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset=iso-8859-1 Gents, Thanks for your input. I just read the pages for Aerodynamics for Naval = Aviators. I did not know that. So the scenario leaving Lajes was 4800 lbs of fuel on board. We knew = from Universal flight planning that we could not make it if the average = winds were greater than 93 knots. We took off and at altitude we took = about 87 knots initially. They did not change much in the climb from = FL220 up to 280. But our fuel flow dropped considerably. They had us = flying at 260 KTS TAS. I pulled the throttles back to set my intuitive = max range attitude. I was not making their planned TAS numbers. But as = the flight went on and we were past their planned equal time points for = loss of an engine, depressurization or just not enough fuel the winds = picked up to 130 KTS in the face. We were committed. So initially it = would seem that we should have pushed up the throttles but then we = pulled them back to save the gas. We obviously made it. =20 After reading the passage and looking over graph I can see that it makes = sense to increase the speed to overcome the headwinds. However, it is = not linear so from the limited equipment in the plane we have no way of = knowing how much to increase your airspeed before you are pissing your = fuel away. I guess the moral of the story is to fly their profile and = maybe call them in flight to run the numbers as well as change the = location of the equal time points as the winds increase significantly. On Dec 17, 2013, at 8:18 AM, Gary Casey wrote: > Yes, a discussion on the effect of a headwind is there, but I'm afraid = the answer isn't. So I put together a calculation that figured it out = for airspeeds typical of my ES. It turns out that with zero wind it is = always more efficient to slow down, at least compared to any "normal" = cruise speed. But to be more realistic of what most of us might = consider important, I typically us a number I call "effectiveness", and = that is the MPG times the speed squared. After all, most of us value = speed quite a bit. For effectiveness, you generally want to go fast. = For best MPG you usually want to add around 1/3 the headwind component = to your speed. For me, that means that while best MPG might be at 120 = TAS with no wind, I would want to add 20 (maybe even 30) knots if I have = a 60-knot headwind. But above 140 to 150 TAS, the MPG is always going = down with increased speed, regardless of any reasonable headwind. I = never fly as slow as 120, so it means that going faster always reduces = fuel economy, headwind or not. As far as "effectiveness", going faster = gets to be a LOT better with a headwind. Yes, go faster into a = headwind, but I don't think that means going from LOP to ROP - that = doesn't get enough speed to pay for itself. And with a tailwind, = definitely slow down - but I have a mental problem doing that! > Gary Casey=20 >=20 >=20 > Check *Aerodynamics for Naval Aviators*. The figure on page 169 and = the > accompanying text on page 170 will answer your question. >=20 > = http://www.faa.gov/regulations_policies/handbooks_manuals/aviation/media/0= 0-80T-80.pdf >=20 > --Mark >=20 >=20 > On Mon, Dec 16, 2013 at 7:00 AM, George Wehrung wrote: >=20 > > Hey guys, > > > > On long range flights I always fly a Max range profile no matter the = wind > > direction. Case in point I logged a 7.5 in a king air 200 flying = from Lajes > > Azores to St Johns Newfoundland today. The winds got up to 122 knots = in the > > face. But with the internal ferry tank we made it with 800 lbs to = spare. > > > > Anyhow the guy next to me wanted to push it up saying we would spend = less > > time bucking the wind but I owned the plane today and flew what I = perceived > > a Max range AOA (no AOA installed) of about 3 degrees nose up and = kept > > pulling the throttles back to keep her their. This attitude comes = from 7 > > yrs in king airs and knowing the charts. But I don't have the aero > > background to counter his argument. > > > > Can anyone help me out with research or otherwise? > > > > I know their is a number of TPS grads and much smarter aviators than = I. > > > > George --Apple-Mail=_E584E6C0-21D3-4408-BB8D-9085E610AC36 Content-Transfer-Encoding: quoted-printable Content-Type: text/html; charset=iso-8859-1 Gents,

Thanks for your input. =  I just read the pages for Aerodynamics for Naval Aviators. =  I did not know that.

So the scenario = leaving Lajes was 4800 lbs of fuel on board.  We knew from = Universal flight planning that we could not make it if the average winds = were greater than 93 knots.  We took off and at altitude we took = about 87 knots initially.  They did not change much in the climb = from FL220 up to 280.  But our fuel flow dropped considerably. =  They had us flying at 260 KTS TAS.  I pulled the throttles = back to set my intuitive max range attitude.  I was not making = their planned TAS numbers.  But as the flight went on and we were = past their planned equal time points for loss of an engine, = depressurization or just not enough fuel the winds picked up to 130 KTS = in the face.  We were committed.  So initially it would seem = that we should have pushed up the throttles but then we pulled them back = to save the gas.  We obviously made it. =  

After reading the passage and looking = over graph I can see that it makes sense to increase the speed to = overcome the headwinds.  However, it is not linear so from the = limited equipment in the plane we have no way of knowing how much to = increase your airspeed before you are pissing your fuel away.  I = guess the moral of the story is to fly their profile and maybe call them = in flight to run the numbers as well as change the location of the equal = time points as the winds increase = significantly.




=

On Dec 17, 2013, at 8:18 AM, Gary Casey <casey.gary@yahoo.com> = wrote:

Yes, a discussion on the = effect of a headwind is there, but I'm afraid the answer isn't.  So = I put together a calculation that figured it out for airspeeds typical = of my ES.  It turns out that with zero wind it is always more = efficient to slow down, at least compared to any "normal" cruise speed. =  But to be more realistic of what most of us might consider = important, I typically us a number I call "effectiveness", and that is = the MPG times the speed squared.  After all, most of us value speed = quite a bit.  For effectiveness, you generally want to go fast. =  For best MPG you usually want to add around 1/3 the headwind = component to your speed.  For me, that means that while best MPG = might be at 120 TAS with no wind, I would want to add 20 (maybe even 30) = knots if I have a 60-knot headwind.  But above 140 to 150 TAS, the MPG = is always going down with increased speed, regardless of any reasonable = headwind.  I never fly as slow as 120, so it means that going = faster always reduces fuel economy, headwind or not.  As far as = "effectiveness", going faster gets to be a LOT better with a headwind. =  Yes, go faster into a headwind, but I don't think that means going = from LOP to ROP - that doesn't get enough speed to pay for itself. =  And with a tailwind, definitely slow down - but I have a mental = problem doing that!
Gary Casey 


Check *Aerodynamics for Naval Aviators*. The figure on page 169 = and the
accompanying text on page 170 will answer your = question.

http://www.faa.gov/regulations_policies/handbooks_manuals/aviation/= media/00-80T-80.pdf

--Mark


On Mon, Dec 16, 2013 = at 7:00 AM, George Wehrung <gw5@me.com> wrote:

> Hey = guys,
>
> On long range = flights I always fly a Max range profile no matter the wind
> = direction. Case in point I logged a 7.5 in a king air 200 flying from = Lajes
> Azores to St = Johns Newfoundland today. The winds got up to 122 knots in the
> face. But with = the internal ferry tank we made it with 800 lbs to spare.
>
> Anyhow the guy = next to me wanted to push it up saying we would spend less
> time bucking the wind but I owned the plane today and flew what I = perceived
> a = Max range AOA (no AOA installed) of about 3 degrees nose up and = kept
> pulling the = throttles back to keep her their. This attitude comes from 7
> yrs in king airs = and knowing the charts. But I don't have the aero
> background to = counter his argument.
>
> = Can anyone help me out with research or otherwise?
>
> I know their is = a number of TPS grads and much smarter aviators than I.
>
> = George

= --Apple-Mail=_E584E6C0-21D3-4408-BB8D-9085E610AC36--