X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Thu, 30 Jun 2011 15:06:20 -0400 Message-ID: X-Original-Return-Path: Received: from elasmtp-masked.atl.sa.earthlink.net ([209.86.89.68] verified) by logan.com (CommuniGate Pro SMTP 5.4.0) with ESMTP id 5038378 for lml@lancaironline.net; Thu, 30 Jun 2011 10:45:44 -0400 Received-SPF: none receiver=logan.com; client-ip=209.86.89.68; envelope-from=colyncase@earthlink.net DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=dk20050327; d=earthlink.net; b=ijczIl40AymapR7JdBlfsqRaCD2uYkXmIM2j3xmpLJ6apzBMou1uQ0HF2VQBGG4r; h=Received:From:Mime-Version:Content-Type:Subject:Date:In-Reply-To:To:References:Message-Id:X-Mailer:X-ELNK-Trace:X-Originating-IP; Received: from [64.223.166.158] (helo=[192.168.1.24]) by elasmtp-masked.atl.sa.earthlink.net with esmtpa (Exim 4.67) (envelope-from ) id 1QcIUQ-0003M8-Ml for lml@lancaironline.net; Thu, 30 Jun 2011 10:45:10 -0400 From: Colyn Case Mime-Version: 1.0 (Apple Message framework v1082) Content-Type: multipart/alternative; boundary=Apple-Mail-932-425428689 Subject: Re: [LML] Re: Ventral Strakes, do they reduce performance? X-Original-Date: Thu, 30 Jun 2011 10:45:10 -0400 In-Reply-To: X-Original-To: "Lancair Mailing List" References: X-Original-Message-Id: X-Mailer: Apple Mail (2.1082) X-ELNK-Trace: 63d5d3452847f8b1d6dd28457998182d7e972de0d01da9403aa9ae26d473d9188d72eadbc047eed2350badd9bab72f9c350badd9bab72f9c350badd9bab72f9c X-Originating-IP: 64.223.166.158 --Apple-Mail-932-425428689 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset=windows-1252 Craig, I may end up in the same place. There are certain turbulence = conditions where you get kind of a nauseating periodic wig-wag. It = would be nice if the yaw damper would help with that.=20 Colyn On Jun 30, 2011, at 7:51 AM, Craig Gainza wrote: > Ron and Colyn, >=20 > 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 strakes and yaw dampers add unneeded aft weight. Ron, I = think you will feel comfortable with the yaw stability after a few more = lessons. =20 >=20 > I have not had any complaints from back seat. >=20 > After similar yaw damper issues as Colyn, Tim Ong suggested I remove = my yaw damper. I removed it after year one and never missed it. >=20 > Craig Gainza >=20 >=20 >=20 >=20 >=20 > To: lml@lancaironline.net > Date: Wed, 29 Jun 2011 07:34:46 -0400 > From: colyncase@earthlink.net > Subject: [LML] Re: Ventral Strakes, do they reduce performance? >=20 > Ronald, >=20 > I had the Mike Custard ventrals and I have to say the plane was quite = stable in yaw. e.g. better than a Mooney Rocket. > However, I also flew N409L in training which is a straight IV and = didn't notice any big problem with yaw stability. > That said, I road in another IVP back seat on a bumpy (thermals ) day = and didn't like the ride at all. Not sure if it was the pilot > or the airplane. >=20 > I am unable to say if the Mike Custard ventrals add a lot more drag as = I never flew my plane without them. You might want to get some = aerodynamic analysis if you go that route. Mike's fins 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 probably = also be made that those big dual fins are overkill. >=20 > I think I agree with Bob that you don't need a ventral fin for cruise = comfort. > 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 angles 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. >=20 > 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. >=20 > Colyn >=20 > On Jun 27, 2011, at 7:34 AM, RONALD STEVENS wrote: >=20 > Hello guys >=20 > Me again, I just had my first lesson with the Lancair 4p (with JC) and = when I took off the plane was wiggling its tail like a happy dog LOL = Nothing scary, but this I can imagine could be annoying for passengers. >=20 > 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, go-arrounds, full power take offs = as well. >=20 > My very near future plane (we are almost closing ;) is a newer one, so = the tail section was already updated to the latest.=20 >=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 Yaw damper (I have the tru-trak sorcerer) and perhaps = also installing those Ventral strakes. >=20 > Does anybody have experience (before and after) with those? And would = you recommend those?=20 >=20 > Thanks =97 Ronald Stevens (Cirrus 1100 hours, Velocity 250 hours, = Lancair 4p student now with 1 hour LOL) >=20 >=20 --Apple-Mail-932-425428689 Content-Transfer-Encoding: quoted-printable Content-Type: text/html; charset=windows-1252 Craig,

I may end up in the same = place.    There are certain turbulence conditions where you = get kind of a nauseating periodic wig-wag.   It would be nice if = the yaw damper would help with = that. 

Colyn

On = Jun 30, 2011, at 7:51 AM, Craig Gainza wrote:

Ron and Colyn,

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 strakes and yaw = dampers add unneeded aft weight.  Ron, I think you will feel = comfortable with the yaw stability after a few more lessons.  

I have not had any = complaints from back seat.

After similar yaw damper issues as = Colyn, Tim Ong suggested I remove my yaw damper.  I removed it = after year one and never missed it.

Craig = Gainza





To: lml@lancaironline.net
Date: = Wed, 29 Jun 2011 07:34:46 -0400
From: colyncase@earthlink.net
Sub= ject: [LML] Re: Ventral Strakes, do they reduce = performance?

Ronald,

I had the Mike Custard = ventrals and I have to say the plane was quite stable in yaw.   = e.g. better than a Mooney Rocket.
However, I also flew N409L = in training which is a straight IV and didn't notice any big problem = with yaw stability.
That said, I road in another IVP back seat = on a bumpy (thermals ) day and didn't like the ride at all.  Not = sure if it was the pilot
or the = airplane.

I am unable to say if the Mike = Custard ventrals add a lot more drag as I never flew my plane without = them.   You might want to get some aerodynamic analysis if you go = that route.   Mike's fins 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 probably also be made that those big = dual fins are overkill.

I think I agree with = Bob that you don't need a ventral fin for cruise comfort.
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 angles 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, 2011, at 7:34 AM, RONALD STEVENS wrote:

Hello = guys

Me again, I just had my first lesson with = the Lancair 4p (with JC) and when I took off the plane was wiggling its = tail like a happy dog LOL Nothing scary, 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, go-arrounds, full power take offs as = well.

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

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 Yaw 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 recommend = those? 

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



= --Apple-Mail-932-425428689--