REFLECTOR: Speed brake usage question

[Jim Sower]

I strongly suspect that the 120 kt limitation is arbitrary and goes all 
the way back to Burt.  He called it, and designed it as, a "Landing 
Brake".  120 kts is a nice round number in the upper region of GA 
pattern speeds.  John has tested it at nearly twice the load you'd 
encounter at 120 kts.
But stouter hinge attach points should do the trick ... Jim S.


kufalk at wi.rr.com wrote:

>What is needed is someone good at aerodynamic engineering who can calculate the force generated at different airspeeds and maybe different deployment angles.  If we knew the forces in play here we could get a better idea on just how strong it needs to be.
>
>
>----- Original Message -----
>From: Scott Derrick <scott at tnstaafl.net>
>Date: Monday, November 8, 2004 11:45 am
>Subject: Re: REFLECTOR: Speed brake usage question
>
>  
>
>>I wonder what the factory says about increasing the extension 
>>speed to 160 
>>kias???  Is it really strong enough for continuos usage at that speed?
>>
>>That would make the brake a much more versatile tool.
>>
>>My fear is it eventually coming off, right into the prop!
>>
>>Scott
>>
>>At 07:44 AM 11/8/2004, you wrote:
>>    
>>
>>>Dave,
>>>
>>>I've already done the test for you.  One time at 160 IAS I hit a good
>>>bump that bumped my head on the ceiling.  My shin bumped several 
>>>      
>>>
>>toggle>switches located at the bottom of the panel (not the best 
>>place for the
>>    
>>
>>>switches), including the speed brake switch.  At first I couldn't 
>>>      
>>>
>>figure>out why I lost 25kn of airspeed until I saw a few indicator 
>>lights on.
>>    
>>
>>>The brake still works fine with no damage.
>>>
>>>John
>>>SGRE
>>>
>>>      
>>>