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RE: Europa-List: Are Vne and Va IAS or =?UTF-8?Q?TAS=3F?

Subject: RE: Europa-List: Are Vne and Va IAS or =?UTF-8?Q?TAS=3F?
From: davidjoyce@doctors.org.uk
Date: Fri, 5 Jan 2018 23:12:41

I can happily accept that IAS is what matters in relation to flutter at
any height, but there is another aspect where I suspect that TAS becomes
more relevant. If you set out to do say a rate 1 turn at altitude you
are going to have to bank more steeply and pull more g and come closer
to a stall than would be the case at the same IAS at lower altitudes. In
most circumstances that wouldn't matter too much, but I guess it means
that as you go up a mountain valley you need progressively more
lateral,space to do an escape 180 turn, (whilst the valley is probably
getting progressively narrower) 

Regards, David Joyce, GXSDJ 

On 2018-01-05 21:03, William Daniell wrote: 

> Bud 
> Does this apply even at the upper altitude range ....say 13k or 15k? 
> Will 
> 
> On Jan 4, 2018 22:19, "Bud Yerly" <budyerly@msn.com> wrote:
> 
> Yep Graham, 
> 
> Airplanes only feel air pressure, not the velocity of the molecule alone. 
> Dynamic
pressure is  Density times Velocity Squared or IAS (actually you have calibrated
then equivalent) is what the airplane feels. Those RV guys got all hung
up on this and confused everyone. 
> 
> Bottom line, what you read on the airspeed indicator counts. TAS is important
(actually Mach number) as the skin heats up due to friction which is a different
ball of wax. I was always a slow speed aero guy to match my mind. 
> 
> Regards, 
> 
> Bud Yerly 
> 
> Sent from Mail [1] for Windows 10 
> 
> -------------------------
> 
> FROM: owner-europa-list-server@matronics.com 
> <owner-europa-list-server@matronics.com>
on behalf of Pete <peterz@zutrasoft.com>
> SENT: Thursday, January 4, 2018 5:49:37 PM 
> 
> TO: europa-list@matronics.com
> SUBJECT: Re: Europa-List: Are Vne and Va IAS or TAS? 
> 
> Hi Ivan, just to confirm, Vd IAS @8000ft DA? 
> 
> Thanks again! 
> Pete 
> 
> On Jan 4, 2018, at 5:21 PM, <ivanshaw@btinternet.com> 
> <ivanshaw@btinternet.com>
wrote:
> 
> All our company aircraft were tested to Vd, 10% over Vne. And not just taken
to the speed but then tested [short stick and rudder raps] to see if any flutter
mode could be excited at Vd. I have performed these tests at/up to 8000ft .
We have never experienced any flutter mode. I also tested the tail plane 
underbalanced
and over balanced with the same results. To my knowledge we have not
had any reported flutter incidence on the entire fleet. As you mentioned Pete
did exceed Vd on a few occasions. 
> 
> Ivan


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