REFLECTOR: 165 kt Gear Extension Speed

Tom Martino tmartino at troubleshooter.com
Sun Dec 4 22:23:13 CST 2005


I can tell you first hand ... that my gear doors made no appreciable
difference in indicated airspeed.

I can indicate 200 knots with or without them.  I could not notice any
difference at all.  

I did away with them.  Keeping it simple!

I also came up with a unique way to close the nose gear doors.  I will
soon post photos.  I wanted to wait until I had 50 hours on it ... which
has come and gone.

The nose door system consists of a cable (similar to the rudder cable)
with a spring on each end.  The cable is looped through an eyelet on the
nose strut and then each spring end is connected to the gear door.  

When the strut is lifted to bring up the gear, the cable pulls on the
doors and the springs keep them tightly closed.  (The cable runs freely
which automatically equals out the pressure on each door.)

When the strut drops, it pulls down on the gear doors to open them.  

I am not sure what gear extension speed is safe to use with no main gear
doors, but there isn't much to falter.  Can anyone venture a guess as to
how much speed the main gear struts can take?

Tom  

-----Original Message-----
From: reflector-bounces at tvbf.org [mailto:reflector-bounces at tvbf.org] On
Behalf Of Scott Derrick
Sent: Sunday, December 04, 2005 7:43 PM
To: Velocity Aircraft Owners and Builders list
Subject: REFLECTOR: 165 kt Gear Extension Speed [bayes][heur]

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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