REFLECTOR: 165 kt Gear Extension Speed

[Joel Smith]

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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