[NSRCA-discussion] Paysant-Le Roux's Oxalyis using a winglet aft of canop...

[JonLowe at aol.com]

My Dad's theory, backed by limited empirical data, is that the T tail will 
help those airplanes with a small vertical, and a tall aft fuselage, by 
directing airflow over the small vertical.  CPLR's airplanes do not have a well 
defined, tall, vertical stab, unlike the Arresti III that Dad tried the T tail on. 
I've flown his Arresti with and without the T tail and couldn't tell the 
difference.  The CPLR airplane has a tall aft fuselage, short defined vertical, that 
would almost certainly be blanked out by the canopy in many attitudes.  Full 
scale airplanes have been known to have similar problems.  The original BD-5 
didn't have a defined vertical.  Instead, it relied on a tall aft fuselage.  
Didn't work, and they had to add a defined vertical stab.  

An extreme example of a tall fuselage and a short vertical is the new BEAM 
F3A model discussed in the pattern area on RCU.  I'd bet a T tail would help it.

Jon Lowe

In a message dated 5/24/2006 10:25:38 PM Central Daylight Time, 
Rcmaster199 at aol.com writes:
Don Lowe discusses a little bit about such devices in the latest MA. One of 
the photos also shows one of his pattern models retrofitted with the device and 
I think he stated that in his set-up it wasn't terribly effective. The amount 
of vertical and horizontal area the little "T tail" adds may be too small for 
a 2 m pattern model, CPLR notwithstanding. 

The concept is a good one tho, and the idea has been around since at least 
the Wright Bros, although they may not have used the wing intreplanes with that 
specific purpose in mind. To my knowledge, Nat Penton originally applied the 
idea on a model more than 20 years ago. I wrote about that and even played with 
it in my own models a bit. Back then, the schedules we flew were not that 
demanding and couldn't really take advantage of the concept, but the schedules we 
fly now certainly will be easier to fly with such appendages on the models.

Now the horizontal surface angled at the correct incidence could possibly be 
enough to counteract the notorious pitch to landing gear that CPLR designs are 
infamous for with top rudder application. On the other hand, CPLR is gifted 
enough pilot to overcome the model deficiency on his own, but hey, if he 
believes it helps, then it does help him and hurts everyone else flying against him.

MattK


 
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