Return-Path: Received: from relay04.roc.ny.frontiernet.net ([66.133.131.37] verified) by logan.com (CommuniGate Pro SMTP 4.2b2) with ESMTP id 3204295 for flyrotary@lancaironline.net; Mon, 03 May 2004 18:43:13 -0400 Received: (qmail 18406 invoked from network); 3 May 2004 22:42:40 -0000 Received: from 65-73-33-136.bras01.cok.tn.frontiernet.net (HELO frontiernet.net) ([65.73.33.136]) (envelope-sender ) by relay04.roc.ny.frontiernet.net (FrontierMTA 2.3.18) with SMTP for ; 3 May 2004 22:42:40 -0000 Message-ID: <4096CB7E.571F74C8@frontiernet.net> Date: Mon, 03 May 2004 17:45:18 -0500 From: Jim Sower X-Mailer: Mozilla 4.77 [en] (Win98; U) X-Accept-Language: en MIME-Version: 1.0 To: Rotary motors in aircraft Subject: Re: VNE and flutter - Was Injector testing References: Content-Type: multipart/alternative; boundary="------------EA9162975C971DBE0CBDA73B" --------------EA9162975C971DBE0CBDA73B Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit <... VNE ( red line ) has to be established at 90% of demonstrated flutter-free speed ...> Well and good. But does the 200 kt VNE mean IAS at SL, or TAS or IAS at any altitude or what?? I've heard that flutter is a function of both Q and V; that there is both an IAS component and a TAS component to the issue. If that is true, I don't know what the relationship might be. Additionally, I am fairly certain that since he has all this power and all, John is going to "expand the envelope" and explore airspeeds above the published 200 kts VNE. The key consideration IMO is what, exactly, is the safest and most reliable way to expand the envelope? Explore higher TAS at altitude (IAS at or below VNE) and having established a flutter free TAS of, say, 250 kts TAS (+ 10% of course) to test at that TAS at lower and lower altitudes until you've arrived at or close to 250 IAS? Start out incrementally, say 5 kts at a time at low altitude and test that IAS at progressively higher altitudes? What kind of test program would get the job done safely and thoroughly? Inquiring minds need to know .... Jim S. Dean wrote: > Jim and John, etal For single engine aircraft certificated > under FAR Part 23, the VNE ( red line ) has to be established > at 90% of demonstrated flutter-free speed. I would certainly > think that it would be in all home-built aircraft designers' > interest to stay close to this 10% minimum margin when > establishing the VNE for their design. You might check with > the Cozy designer. Dean Van Winkle ( Retired Aero > Engineer/Flight Test Engineer )RV-9A Fus/Finish 13B NA > > ----- Original Message ----- > From: Jim Sower > To: Rotary motors in aircraft > Sent: Monday, May 03, 2004 9:41 AM > Subject: [FlyRotary] Re: Injector testing > <... VNE for the plans model Cozy IV is 220 mph ... > if I can cruise at 200 kts I'll be happy ...> > 200 kts is 230 mph. > > John Slade wrote: > > > >What would be common for an O-360 powered > > plane? I think VNE for the plans model Cozy IV is > > 220mph That's IAS for some reason I never quite > > followed.> What sort of top speed, and cruise > > speed do you expect? I really don't know. If I can > > cruise at 200 kts I'll be happy. Anything over > > that is gravy. Top speed is only for bragging > > rights anyway - right?John (planning to beat all > > the RVs in races) > > -- > Jim Sower ... Destiny's Plaything > Crossville, TN; Chapter 5 > Long-EZ N83RT, Velocity N4095T > > -- Jim Sower ... Destiny's Plaything Crossville, TN; Chapter 5 Long-EZ N83RT, Velocity N4095T --------------EA9162975C971DBE0CBDA73B Content-Type: text/html; charset=us-ascii Content-Transfer-Encoding: 7bit <... VNE ( red line ) has to be established at 90% of demonstrated flutter-free speed ...>
Well and good.  But does the 200 kt VNE mean IAS at SL, or TAS or IAS at any altitude or what??
I've heard that flutter is a function of both Q and V; that there is both an IAS component and a TAS component to the issue.  If that is true, I don't know what the relationship might be.  Additionally, I am fairly certain that since he has all this power and all, John is going to "expand the envelope" and explore airspeeds above the published 200 kts VNE.  The key consideration IMO is what, exactly, is the safest and most reliable way to expand the envelope?  Explore higher TAS at altitude (IAS at or below VNE) and having established a flutter free TAS of, say, 250 kts TAS (+ 10% of course) to test at that TAS at lower and lower altitudes until you've arrived at or close to 250 IAS?  Start out incrementally, say 5 kts at a time at low altitude and test that IAS at progressively higher altitudes?  What kind of test program would get the job done safely and thoroughly?

Inquiring minds need to know .... Jim S.
 

Dean wrote:

Jim and John, etal For single engine aircraft certificated under FAR Part 23, the VNE ( red line ) has to be established at 90% of demonstrated flutter-free speed. I would certainly think that it would be in all home-built aircraft designers' interest to stay close to this 10% minimum margin when establishing the VNE for their design.  You might check with the Cozy designer. Dean Van Winkle ( Retired Aero Engineer/Flight Test Engineer )RV-9A  Fus/Finish  13B NA
----- Original Message -----
From: Jim Sower
Sent: Monday, May 03, 2004 9:41 AM
Subject: [FlyRotary] Re: Injector testing
 <... VNE for the plans model Cozy IV is 220 mph ... if I can cruise at 200 kts I'll be happy ...>
200 kts is 230 mph.

John Slade wrote:

>What would be common for an O-360 powered plane? I think VNE for the plans model Cozy IV is 220mph That's IAS for some reason I never quite followed.> What sort of top speed, and cruise speed do you expect? I really don't know. If I can cruise at 200 kts I'll be happy. Anything over that is gravy. Top speed is only for bragging rights anyway - right?John (planning to beat all the RVs in races)
--
Jim Sower ... Destiny's Plaything
Crossville, TN; Chapter 5
Long-EZ N83RT, Velocity N4095T
 

--
Jim Sower ... Destiny's Plaything
Crossville, TN; Chapter 5
Long-EZ N83RT, Velocity N4095T
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