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Re: Berube Gear - more thoughts

Subject: Re: Berube Gear - more thoughts
From: ami mcfadyean <ami@mcfadyean.freeserve.co.uk>
Date: Mon, 4 Sep 2000 23:44:37

Don`t agree. The monowheel and the trigear are both structurally 
inefficient in that the load path between CG and undercarriage structure 
are longer than is the case with the fixed taildragger. The latter 
pick-up close to the CG and make some use of the forward lift-pin 
attachment which is designed to take loads (whilst in flight). The 
monowheel takes the whole weight of the aircraft and its payload 
(excepting engine weight) through the eight 3/16" bolts that hold in 
LG01.

Stresses tend to migrate outboard in the structure, which makes the 
tunnel a relatively redundant member, except as a useful arm rest and to 
provide strength and energy absorption in a crash.

Duncan McFadyean

.
    -----Original Message-----
    From: Shaun Simpkins <shauns@hevanet.com>
    Date: Sunday, September 03, 2000 6:15 AM
    Subject: Berube Gear - more thoughts
   
   
    After looking at the Berubeand HB-YIB conventional gear photos 
again, and comparing them to other installations, I'm not convinced that 
this installation is as robust as the monowheel or trigear.
    
    The gear is apparently placed under the seat pan.  The monowheel 
ties in to the engine mount, and loads are transmitted through the 
firewall and tunnel to the rest of the fuselage.  The trigear mains 
appear to tie in to the main spar.  Either of these locations is great, 
as this is where the body structure is strongest.  I'm a little worried 
about the structural strengthening required. 
    
    If we consider the Van's RV gear arrangement, the mains angle back 
---From the engine mount, making for a light and efficient structure.  This 
arrangement would take advantage of the structure already in place for 
the monowheel, but the engine mount and footwells probably prevent this.
    
    Just thoughts-
    
    Shaun



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