REFLECTOR: Reflector Digest, Vol 84, Issue 85 - Vtwin update

Mon Mar 19 21:17:16 CDT 2012

I spoke with John Abraham at the factory this morning. He said the first flight went off without any excitement. They are in the process of getting ready for paint. Scott Swing is hard at work getting everything finished up. They will paint the twin in the next couple days and fly it down to Sun 'n Fun at the end of the week. I can't wait to see pictures of the finished product. 

Mark
On Mar 19, 2012, at 8:53 PM, reflector-request at tvbf.org wrote:

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> Today's Topics:
> 
>   1. Re:  444DX update (David Ullman)
>   2. Re:  444DX update (Peter Braswell)
>   3.  Velocity Twin First Flight (Darrell & Nora Kufalk)
>   4.  Nose Gear Shimmy (Donald Bates)
>   5. Re:  Velocity Twin First Flight (Alex Balic)
> 
> 
> ----------------------------------------------------------------------
> 
> Message: 1
> Date: Mon, 19 Mar 2012 10:34:38 -0700
> From: "David Ullman" <ullman at robustdecisions.com>
> To: <reflector at tvbf.org>
> Subject: Re: REFLECTOR: 444DX update
> Message-ID: <09d901cd05f6$8f96f0a0$aec4d1e0$@com>
> Content-Type: text/plain;	charset="us-ascii"
> 
> Last week we transitioned from my test pilot to me.  I have now flown 444DX
> twice, solo.  I have about 1.5 hours so far.  Weather in the NW is not
> cooperating (big surprise for March).  But I am getting sufficient time to
> generate and fix a squawk list as expected.  I am working off a 5000ft
> runway until I get better speed control, landings are improving.  I will
> provide some numbers like takeoff/landing distance as I generate them.  
> 
> First landing had a good tension breaker as when I was on final another
> plane pulled on the runway without announcing or paying any attention to me
> barreling along at near 100kts (I am approaching fast until I get my speed
> control skills better).  I buzzed him and went around.  It did break the
> tension as I did all the right things and he didn't.
> 
> Waiting for clear skies in Oregon
> 
> David Ullman
> N-444DX Velocity 
> EAA 292 President
> david at davidullman.com
> 541-754-3609
> 
> 
> 
> ------------------------------
> 
> Message: 2
> Date: Mon, 19 Mar 2012 14:19:44 -0400
> From: Peter Braswell <peter.braswell at gmail.com>
> To: Velocity Aircraft Owners and Builders list <reflector at tvbf.org>
> Subject: Re: REFLECTOR: 444DX update
> Message-ID:
> 	<CAP6bQxEN2yOwW2ezDm5_C0S8_acJOKUbUbYmctqpTyDgufNP_Q at mail.gmail.com>
> Content-Type: text/plain; charset="iso-8859-1"
> 
> David,
> Very cool!  Sounds like you're making progress.  Keep the reports coming
> it, gives a tremendous amount of motivation to those of us still building!
> 
> Best,
> Peter
> 
> ------------------------------------------------------------------------
> *"It's a Jungle Up There": www.zuluworks.com*
> *Great Aviation Gear: www.sky-gadgets.com*
> ------------------------------------------------------------------------
> 
> 
> 
> On Mon, Mar 19, 2012 at 1:34 PM, David Ullman <ullman at robustdecisions.com>wrote:
> 
>> Last week we transitioned from my test pilot to me.  I have now flown 444DX
>> twice, solo.  I have about 1.5 hours so far.  Weather in the NW is not
>> cooperating (big surprise for March).  But I am getting sufficient time to
>> generate and fix a squawk list as expected.  I am working off a 5000ft
>> runway until I get better speed control, landings are improving.  I will
>> provide some numbers like takeoff/landing distance as I generate them.
>> 
>> First landing had a good tension breaker as when I was on final another
>> plane pulled on the runway without announcing or paying any attention to me
>> barreling along at near 100kts (I am approaching fast until I get my speed
>> control skills better).  I buzzed him and went around.  It did break the
>> tension as I did all the right things and he didn't.
>> 
>> Waiting for clear skies in Oregon
>> 
>> David Ullman
>> N-444DX Velocity
>> EAA 292 President
>> david at davidullman.com
>> 541-754-3609
>> 
>> _______________________________________________
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>> user:pw = tvbf:jamaicangoose
>> Check new archives: www.tvbf.org/pipermail
>> Check old archives: http://www.tvbf.org/archives/velocity/maillist.html
>> 
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> ------------------------------
> 
> Message: 3
> Date: Mon, 19 Mar 2012 16:52:41 -0500
> From: "Darrell & Nora Kufalk" <kufalk at wi.rr.com>
> To: <reflector at tvbf.org>
> Subject: REFLECTOR: Velocity Twin First Flight
> Message-ID: <01c801cd061a$9bcb9820$d362c860$@wi.rr.com>
> Content-Type: text/plain; charset="us-ascii"
> 
> Scroll to the bottom.
> 
> http://www.velocityaircraft.com/airplane-models-vtwin%20-%20updates.html
> 
> Not much info.  Anyone know more?
> 
> 
> 
> 
> 
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> ------------------------------
> 
> Message: 4
> Date: Mon, 19 Mar 2012 16:36:21 -0700 (PDT)
> From: Donald Bates <aeroopt at yahoo.com>
> To: "reflector at tvbf.org" <reflector at tvbf.org>
> Subject: REFLECTOR: Nose Gear Shimmy
> Message-ID:
> 	<1332200181.43563.YahooMailNeo at web181501.mail.ne1.yahoo.com>
> Content-Type: text/plain; charset="utf-8"
> 
> Velocity Nose Wheel Shimmy
> Explained
> ?
> Recent comments have focused
> on wheel balance. A well balanced wheel can prevent varying side loads while
> rolling and turning, which may initiate or contribute to shimmy. Here is what
> else I learned while fixing my shimmy problem.
> ?
> Poor shimmy axis alignment can
> also initiate or contribute to shimmy. The shimmy axis must be truly vertical
> in the sidewise plane. With sidewise lean the weight of the airplane will force
> the wheel to turn out of the vertical fore-and-aft longitudinal plane, while
> the caster arm will tend to center the wheel thus initiating a shimmy.
> ?
> If the shimmy axis is raked
> forward at the bottom in the fore-and-aft vertical plane, the tire-ground
> contact point will be aft and under the shimmy axis extension. Again the weight
> of the airplane will tend to force the wheel to turn outward while caster tends
> to center the wheel which can initiate a shimmy. 
> ?
> If the shimmy axis is raked
> aft, the tire contact point will be aft but above the axis extension and the
> weight will now tend to force the wheel to center giving us two centering
> forces. This is a stable or convergent geometry rather than divergent. How much
> aft rake is needed? On my SERG the shock in the retractable nose gear actuator linkage
> allows about a 4-5 degree forward rake when compressed. The Diamond trainer
> aircraft has a similar nose gear setup and I measured about 8 degrees on their
> shimmy axis so anything in the 5-8 degree range should work well. 
> ?
> Getting the nose gear leg
> adjusted for enough aft-rake may require more room at the top of the gear leg.
> I had to cut a two inch diameter hole in my gear-canard bulkhead and pivot
> channel to allow space for the clevis at the top of the gear leg. However, even
> with a balanced wheel and good shimmy axis alignment, a shimmy damper is still
> needed in case the wheel isn?t centered at touch-down.
> ?
> The viscous shimmy damper is
> preferable. The friction dampers have a problem generally called sticktion or
> static coefficient of friction. It is quite a bit higher than the sliding
> coefficient of friction. If the wheel is turned at touch-down the initial resistance
> to centering is high. As soon as it begins to slide to the center the friction
> drops suddenly and there is then an excess over-force that gives the wheel a
> kick and accelerates it across to the other side, and this kick repeats every
> time the shimmy reverses direction. This can result in a very hard shimmy especially
> in a touch-down hard enough to force the wheel to turn outward, if there is
> forward rake, before it starts to center. It can be very destructive. Don?t ask
> how I know.
> ?
> The viscous damper eliminates
> the sticktion factor of a friction type damper and can be designed with a
> higher shimmy resistance to help stop the shimmy quicker. I designed and built
> my own viscous damper before I knew of the new Velocity viscous damper which is
> a bargain compared to my machine shop costs. It may be all you need and you
> will find it takes less braking to steer the airplane. However, if your damper
> leaks, having a balanced wheel and good shimmy axis alignment provides an extra
> margin of safety. 
> ?
> Don Bates
> N14B
> SERG
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> ------------------------------
> 
> Message: 5
> Date: Mon, 19 Mar 2012 19:54:21 -0500
> From: "Alex Balic" <velocity_pilot at verizon.net>
> To: "'Velocity Aircraft Owners and Builders list'"
> 	<reflector at tvbf.org>
> Subject: Re: REFLECTOR: Velocity Twin First Flight
> Message-ID: <001001cd0633$fc89a3f0$f59cebd0$@net>
> Content-Type: text/plain; charset="us-ascii"
> 
> Santa's elves must work down at the factory during the offseason. 
> 
> 
> 
> From: reflector-bounces at tvbf.org [mailto:reflector-bounces at tvbf.org] On
> Behalf Of Darrell & Nora Kufalk
> Sent: Monday, March 19, 2012 4:53 PM
> To: reflector at tvbf.org
> Subject: REFLECTOR: Velocity Twin First Flight
> 
> 
> 
> Scroll to the bottom.
> 
> http://www.velocityaircraft.com/airplane-models-vtwin%20-%20updates.html
> 
> Not much info.  Anyone know more?
> 
> 
> 
> 
> 
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> End of Reflector Digest, Vol 84, Issue 85
> *****************************************