X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Thu, 30 Jun 2011 07:51:17 -0400 Message-ID: X-Original-Return-Path: Received: from blu0-omc3-s35.blu0.hotmail.com ([65.55.116.110] verified) by logan.com (CommuniGate Pro SMTP 5.4.0) with ESMTP id 5037768 for lml@lancaironline.net; Thu, 30 Jun 2011 00:37:20 -0400 Received-SPF: pass receiver=logan.com; client-ip=65.55.116.110; envelope-from=cgainza@msn.com Received: from BLU139-W32 ([65.55.116.74]) by blu0-omc3-s35.blu0.hotmail.com with Microsoft SMTPSVC(6.0.3790.4675); Wed, 29 Jun 2011 21:36:45 -0700 X-Original-Message-ID: X-Original-Return-Path: cgainza@msn.com Content-Type: multipart/alternative; boundary="_28a86fd0-864f-4345-aff3-02e08dff0d5d_" X-Originating-IP: [24.5.212.73] From: Craig Gainza X-Original-To: list lancair Subject: RE: [LML] Re: Ventral Strakes, do they reduce performance? X-Original-Date: Wed, 29 Jun 2011 21:36:45 -0700 Importance: Normal In-Reply-To: References: MIME-Version: 1.0 X-OriginalArrivalTime: 30 Jun 2011 04:36:45.0686 (UTC) FILETIME=[51525960:01CC36DF] --_28a86fd0-864f-4345-aff3-02e08dff0d5d_ Content-Type: text/plain; charset="Windows-1252" Content-Transfer-Encoding: quoted-printable Ron and Colyn=2C After almost 800 hours on our piston IV-P (many with back seat passengers) = my bigger concern would be the added weight in back. My opinion is that st= rakes and yaw dampers add unneeded aft weight. Ron=2C I think you will fee= l comfortable with the yaw stability after a few more lessons. =20 I have not had any complaints from back seat. After similar yaw damper issues as Colyn=2C Tim Ong suggested I remove my y= aw damper. I removed it after year one and never missed it. Craig Gainza To: lml@lancaironline.net Date: Wed=2C 29 Jun 2011 07:34:46 -0400 From: colyncase@earthlink.net Subject: [LML] Re: Ventral Strakes=2C do they reduce performance? Ronald=2C I had the Mike Custard ventrals and I have to say the plane was quite stabl= e in yaw. e.g. better than a Mooney Rocket.However=2C I also flew N409L i= n training which is a straight IV and didn't notice any big problem with ya= w stability.That said=2C I road in another IVP back seat on a bumpy (therma= ls ) day and didn't like the ride at all. Not sure if it was the pilotor t= he airplane. I am unable to say if the Mike Custard ventrals add a lot more drag as I ne= ver flew my plane without them. You might want to get some aerodynamic an= alysis if you go that route. Mike's fins were definitely designed to solv= e a real problem with the turbines so if an argument could be made that ven= trals have any use on a piston it could probably also be made that those bi= g dual fins are overkill. I think I agree with Bob that you don't need a ventral fin for cruise comfo= rt.My interest in them was somewhat speculative and in relation to stalls. = The thought was that the vstab is largely blanketed by the wing at high a= ngles of attack so that a ventral fin might be more effective for avoiding = a yaw departure. I will probably never know the answer to that but I will= note that the Columbia 400 has a ventral fin. As far as the yaw damper goes. I have a Sorcerer with the yaw damper. So = far i haven't got it do anything useful in turbulence. I'm still working = with Tru-Trak on that. Colyn On Jun 27=2C 2011=2C at 7:34 AM=2C RONALD STEVENS wrote:Hello guys Me again=2C I just had my first lesson with the Lancair 4p (with JC) and wh= en I took off the plane was wiggling its tail like a happy dog LOL Nothing = scary=2C but this I can imagine could be annoying for passengers. Now I was looking on the internet and found that Ventral Strakes were used= to fight against those 'yaw' effects.It suppose to help with turbulence=2C= go-arrounds=2C full power take offs as well. My very near future plane (we are almost closing =3B) is a newer one=2C so = the tail section was already updated to the latest.=20 But looking at my passengers (I fly with my Son and Girlfriend a lot) this = could be disturbing for them and I was already thinking of installing the Y= aw damper (I have the tru-trak sorcerer) and perhaps also installing those = Ventral strakes. Does anybody have experience (before and after) with those? And would you r= ecommend those?=20 Thanks =97 Ronald Stevens (Cirrus 1100 hours=2C Velocity 250 hours=2C Lanca= ir 4p student now with 1 hour LOL) = --_28a86fd0-864f-4345-aff3-02e08dff0d5d_ Content-Type: text/html; charset="Windows-1252" Content-Transfer-Encoding: quoted-printable
Ron and Colyn=2C

After almost 800 hours on our piston IV-P (many wit= h back seat passengers) my bigger concern would be the added weight in back= . =3B My opinion is that strakes and yaw dampers add unneeded aft weigh= t. =3B Ron=2C I think you will feel comfortable with the yaw stability = after a few more lessons. =3B

I have not had any complaints fro= m back seat.

After similar yaw damper issues as Colyn=2C Tim Ong sug= gested I remove my yaw damper. =3B I removed it after year one and neve= r missed it.

Craig Gainza





To: lml@lancaironline.net
Date: Wed=2C 29 Jun 2011 07:34:46 -0= 400
From: colyncase@earthlink.net
Subject: [LML] Re: Ventral Strakes= =2C do they reduce performance?

Ronald=2C

<= /div>
I had the Mike Custard ventrals and I have to say the plane was q= uite stable in yaw.  =3B e.g. better than a Mooney Rocket.
Ho= wever=2C I also flew N409L in training which is a straight IV and didn't no= tice any big problem with yaw stability.
That said=2C I road in a= nother IVP back seat on a bumpy (thermals ) day and didn't like the ride at= all.  =3BNot sure if it was the pilot
or the airplane.
=

I am unable to say if the Mike Custard ventrals add a l= ot more drag as I never flew my plane without them.  =3B You might want= to get some aerodynamic analysis if you go that route.  =3B Mike's fin= s were definitely designed to solve a real problem with the turbines so if = an argument could be made that ventrals have any use on a piston it could p= robably also be made that those big dual fins are overkill.

<= /div>
I think I agree with Bob that you don't need a ventral fin for cr= uise comfort.
My interest in them was somewhat speculative and in= relation to stalls.  =3B The thought was that the vstab is largely bla= nketed by the wing at high angles of attack so that a ventral fin might be = more effective for avoiding a yaw departure.  =3B I will probably never= know the answer to that but I will note that the Columbia 400 has a ventra= l fin.

As far as the yaw damper goes. I have a Sor= cerer with the yaw damper.  =3B So far i haven't got it do anything use= ful in turbulence.  =3B I'm still working with Tru-Trak on that.
<= div>
Colyn

On Jun 27=2C 20= 11=2C at 7:34 AM=2C RONALD STEVENS wrote:

Hell= o guys

Me again=2C I just had my first lesson with= the Lancair 4p (with JC) and when I took off the plane was wiggling its ta= il like a happy dog LOL Nothing scary=2C but this I can imagine could be an= noying for passengers.

Now I was looking on the in= ternet and found that =3BVentral Strakes  =3Bwere = used to fight against those 'yaw' effects.
It suppose to help wit= h turbulence=2C go-arrounds=2C full power take offs as well.

=
My very near future plane (we are almost closing =3B) is a newer= one=2C so the tail section was already updated to the latest. =3B

But looking at my passengers (I fly with my Son and Gi= rlfriend a lot) this could be disturbing for them and I was already thinkin= g of installing the Yaw damper (I have the tru-trak sorcerer) and perhaps a= lso installing those Ventral strakes.

Does anybody= have experience (before and after) with those? And would you recommend tho= se? =3B

Thanks =97 Ronald Stevens (Cirrus 1100= hours=2C Velocity 250 hours=2C Lancair 4p student now with 1 hour LOL)

= --_28a86fd0-864f-4345-aff3-02e08dff0d5d_--