REFLECTOR: Cruise speed "speed brake" & Glass O'cast

michalk michalk at awpi.com
Tue Sep 6 14:54:47 CDT 2005 

The diode would allow you to retract the speedbreak if the cutout switch 
were engaged.

Jim Sower wrote:
> <<flip the switch to extend the board, and let the cutout switch decide 
> when to extend it some more What would happen if you were cruising at 
> low IAS (say at 15k'), extended the board, dumped the nose and 
> accelerated to some point beyond the limit?  Sounds like your scheme 
> would prevent you from extending at excessive speed, but not be able to 
> retract it if the speed became excessive after it was already extended.
> Am I reading you right? ... Jim S.
> 
> michalk wrote:
> 
>> Incrementally extending...
>>
>> I was just thinking about this on your first post.
>>
>> It seems it would be quite simple to add a force actuated switch that 
>> would not exceed some limit.
>>
>> I do not remember what the current actuators are rated for, but let's 
>> assume they are 100lbs.
>>
>> Make a collar that fits around the keel end of the actuator, with a 
>> spring with the appropriate K factor to move .25 inches when 75lbs is 
>> applied.  Put a switch in series with the actuator, with a diode so 
>> that the switch is bypassed if you want to retract while the cutout 
>> switch is engaged.  Normal operation would bypass the diode (no 
>> voltage drop), when the cutout switch is not engaged.
>>
>> Want to go down? just flip the switch to extend the board, and let the 
>> cutout switch decide when to extend it some more.  Just don't exceed 
>> the limits by increasing your airspeed.
>>
>> I suppose one could get fancier with a DPDT switch that would retract 
>> it if the forces get too high, but I haven't put enough brain cells 
>> into that problem.
>>
>>
>> Scott Derrick wrote:
>>
>>> I would hate to give up my separate rudder controls and yes they do 
>>> act as a speed break, but fairly weak compared to the belly board and 
>>> a major PITA to use on an extended cruise descent.
>>>
>>> I want something I can turn on and basically fly the airplane in a 
>>> normal manner, except for the fact I'm able to descend fairly quickly 
>>> under power.
>>>
>>> Beefing up the belly board really seems to me to be the best option.  
>>> Possibly adding controls to be able to incrementally extend it at 
>>> preset points.
>>> Scott
>>>
>>>
>>> Terry Miles wrote:
>>>
>>>> I'm not flying yet, but I understand that (both rudders at once) 
>>>> feature
>>>> is not on later versions of the Velocity.
>>>> New topic:  Rich, thanks for the pics of Oshkosh.
>>>> Terry
>>>>
>>>> -----Original Message-----
>>>> From: reflector-bounces at tvbf.org [mailto:reflector-bounces at tvbf.org] On
>>>> Behalf Of Kufalk
>>>> Sent: Monday, September 05, 2005 4:18 PM
>>>> To: Velocity Aircraft Owners and Builders list
>>>> Subject: Re: REFLECTOR: Cruise speed "speed brake"
>>>>
>>>>
>>>> Terry wrote...   "Another thought only, how about a split rudder like
>>>> the
>>>> B-727."
>>>>
>>>>
>>>> Don't all canard pushers already have split rudders?
>>>>
>>>> If you want to slow down from cruise speed without reducing power, why
>>>> not just press both rudders at the same time?
>>>>
>>>> Darrell
>>>>
>>>>
>>>>
>>>> ----- Original Message ----- From: "Terry Miles" 
>>>> <terrence_miles at hotmail.com>
>>>> To: "'Velocity Aircraft Owners and Builders list'" <reflector at tvbf.org>
>>>> Sent: Monday, September 05, 2005 6:32 AM
>>>> Subject: RE: REFLECTOR: Cruise speed "speed brake"
>>>>
>>>>
>>>>  
>>>>
>>>>> Chuck,
>>>>>
>>>>> You can add me to the list of interested parties.  Here is all I have.
>>>>> In a brief and non-technical exchange w/ Scott Baker on this topic 
>>>>> back about 6 months ago, comments expressed at that time were that 
>>>>> there was a general safety concern about the panel coming off at 
>>>>> higher airloads and going into the prop.  So a conservative speed 
>>>>> limit was established and no testing was done above that speed.  And
>>>>>   
>>>>
>>>>
>>>>
>>>> further there was no
>>>>  
>>>>
>>>>> interest in incremental deployment angles.   Another thought only, how
>>>>> about a split rudder like the B-727.  Only this one would split and 
>>>>> the low half both LH and RH would deflect into the slip stream.  
>>>>> The problem solved is not it out of the prop track, but the problem 
>>>>> created is the deflection is way to far from centerline in the 
>>>>> event of assym deployment malfunctions.  Good luck with this.  Keep 
>>>>> us posted.
>>>>>
>>>>> Terry
>>>>> XL-RG with a SB
>>>>>
>>>>> -----Original Message-----
>>>>> From: reflector-bounces at tvbf.org [mailto:reflector-bounces at tvbf.org]
>>>>> On Behalf Of Chuck Harbert
>>>>> Sent: Monday, September 05, 2005 3:54 AM
>>>>> To: reflector at tvbf.org
>>>>> Subject: REFLECTOR: Cruise speed "speed brake"
>>>>>
>>>>>
>>>>> Scott, I too have wondered if there was a way to install a high speed
>>>>> speed brake like the one on the Mooney 201 that pops up on the 
>>>>> upper surface of
>>>>> the wing to kill the lift. It was great to get down in a hurry without
>>>>> puting the engine at idle. I wondered if you could install this
>>>>> electrically
>>>>> activated "fence" at the outboard edge of the strake in the wing bolt
>>>>> cavity, or inside the wing attached to the spar? They're not that
>>>>>   
>>>>
>>>>
>>>>
>>>> large
>>>>  
>>>>
>>>>> as I
>>>>> recall. They fail safe in the down position and have a warning light
>>>>> when
>>>>> deployed, as I recall.
>>>>>
>>>>> I think that this might be a better way because it kills lift, rather
>>>>> than just dirtying up the plane, and possibly making it unstable. I 
>>>>> have the underbelly speed brake in my RG and it definetely works 
>>>>> well for landing,
>>>>> but I'd love to have a real speed brake. I'll try to get a look at the
>>>>> Mooney's speed brake and send everybody the info.
>>>>>
>>>>> Chuck H
>>>>>
>>>>>
>>>>> -------------------------
>>>>> Scott Derrick wrote:
>>>>>
>>>>>  
>>>>>
>>>>>> I think the standard speed brake is limited to 120 knot extension
>>>>>> speed.  Which limits its uses to in the pattern.
>>>>>>
>>>>>> Has anybody experimented with beefing it up to allow higher speed
>>>>>> extensions?  Like 175 knots?  This would make it a true speed brake.
>>>>>>
>>>>>> I would like something I could deploy at cruise to enable a cruise
>>>>>> speed descent without shock cooling the engine.
>>>>>>
>>>>>> What would you think would be needed to do this?  bigger hinges?
>>>>>> bigger actuator?  carbon fiber door?
>>>>>>     
>>>>>
>>>>>
>>>>>
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>>>>
>>>>
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>>>>  
>>>>
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>>
>>
>>
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>>
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