REFLECTOR: 165 kt Gear Extension Speed

Sun Dec 4 23:40:34 CST 2005

I was flying a Long EZ for a while- didn't like the speed brake, because
it was very difficult to deploy (manual handle) so I would either use
the dual rudder idea for minor drag application, or pull some 2-3 G
s-turns/ 360 turns to load up the wings (very effective to bleed off
energy and kind of fun too) when I get my no-speed brake XLRG flying
(spring?) will experiment with doing the same- hopefully someone will
have a working Cato installation by that time too....... would rather
not have to experiment with the gear speed and find out the hard way
that the doors could not take high speed.......

-----Original Message-----
From: reflector-bounces at tvbf.org [mailto:reflector-bounces at tvbf.org] On
Behalf Of Joel Smith
Sent: Sunday, December 04, 2005 10:07 PM
To: Velocity Aircraft Owners and Builders list
Subject: Re: REFLECTOR: 165 kt Gear Extension Speed

If you look closely,  the wheel wells for the T210 are behind the main 
body most likely in a low pressure zone. Cessna claims that the removal 
of the gear doors did not reduce it's speed. My observations and others 
support this, however I have heard that if you aft load the T210 (which 
is pretty hard to do staying within the station limitations) you will 
incur a 2-3 Kt speed loss. This would make sense to me given that this 
probably exposes the open wheel wells to more air flow.

I believe that open wheel wells on the Velocity would be a lot more 
costly given that they can not be obscured in a low pressure zone. I 
believe that the main gear doors should remain. I believe that they 
could be strengthen to tolerate the higher speeds. The additional 
support for the gear doors (depending on design) may increase gear down 
drag.

I think the nose gear doors would be most challenging. I am not sure the

T210 nose gear doors are any stronger than the Velocity nose gear doors,

but I think there may be less drag on them. One might be able to make an

internal shroud for the nose gear to protect the internals.

I definitely agree that the high gear speed on the T210 is a nice ace to

hold. But I seldom put mine down above 120 Kts. It just increases 
maintenance cost and I feel is unnecessary. If necessary, a turn can get

you down.

I am not convinced having a higher gear speed on a Velocity offers any 
safety points.

Joel

79 T210N
Std. RG

Scott Derrick wrote:

> I have been flying a T210 lately and can't say enough about how 
> versatile the 165 Kt gear extension speed is.  Once extended you can 
> run up to Vne.  This 210 does not have any main gear doors, just nose 
> gear doors.
> Yesterday I was flying in from Las Cruces, was day dreaming and 
> suddenly realized I was 15 miles from the airport at 10,500 and needed

> to be down to 7,500 in  10-12 miles, and slowed down to 120 kts when 
> reaching 7,500.   Totally impossible in my V.   I let the gear down,  
> and without touching anything else was descending at 800ft a minute at

> 150 kts indicated.  I pulled 2 inches of MAP every 2 minutes, and made

> a straight in with no problems, no stress...   All because I could 
> extend the gear at such a high speed.
>
> My V should cruise much faster once I'm back in the air and I'm 
> concerned about being able to slow down or descend rapidly if 
> required, and not abuse the engine by having to pull the throttle from

> 75% to idle.  The only option in a Velocity cruising above 120 kts..  
> Well you can extend both rudders but thats not nearly enough.
>
> I have considered modifying the speed brake, but not sure what would 
> be needed to insure it wouldn't depart the airframe at 165 kts if 
> extended, much less 200 Kts..
> So I'm now considering emulating the T210.
>
> First by removing most of the main doors:
>     Leave the portion that covers the brake unit attached but beef it
up.
>     Leave the short portion that seals off the fuselage when the gear 
> is up, and beef that piece up too.
>     Glass the brake line onto the gear leg, or add a fiberglass 
> channel for it to sit in(not carve out but add a 'U' channel).
>   Then beef up the nose gear doors and hinge points.      A couple 
> carbon fiber layers on the inside of the doors
>      Reinforce the hinges and fuselage pivot points with carbon fiber
>    I wonder if the nose gear extension mechanism(rods, sliders, hyd 
> ram, etc) would be up to a 165 kt extension?   Somebody had mentioned 
> they were testing a simplified nose gear door mechanism that used the 
> nose strut to extend the doors, is this working?
>
> I remember reading a post from Scott Baker that the gear extended 
> speed, sans doors, was Vne, like the T210.  Is this correct?
>
> I also remember reading that a couple of folks have tested their 
> planes with and without main doors with no noticable speed loss.  
> Correct?
>
> Sound sensible?  I really think with the high cruise speeds of the 
> Velocity, being able to extend the gear at around 165 kts, would 
> really enhance its capability and safety.
>
> Scott
>
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