SEN-449 August 4 2000
- Category: Archive 2000
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News and Reports 2000 - second half
SCAT Electronic News 4 August 2000 issue 449
Table of Contents
Batiuk's Bog? - Bogie
Blunt noses - Andressen
SCAT Electronic News - SEN
As unofficial contact between the SEN and the Luddites, I offer the following
from Al Hotard.
The Lost Hills field is one big super dry desert without any water. Right?
Wrong!! At the recent Max Men Summer Contest in July, a well known FAI
flyler, whose initials are "GB" somehow managed to get his truck stuck in
soft mud, up to the hub caps and had to be pulled out, believe it or not! He
was cutting across from one dirt road to another west of the flight line
after the contest was over, when he sank down into the goo. There seems to
be underground steam no one knew about. Now-----shall we name it "GB's
Bayou," or "GB's Slough" or what???
At Thursday's meeting of the Luddites and the writer, it was told that Bob
Van Nest pulled George out with his truck after which both replaced their
trucks due to the goo gumming up things under the frames of their trucks.
This bog is well west almost to the crops but south of them. There is no
indication of the bog from the surface of the ground. The goo seems to be
under a layer of dirt and sand. The area probably will be visited this
weekend at Hector's Saturday evening do.
Blunt nose airfoils tend to have a higher stall angle as well as higher lift
slope. I would assume the greater stall angle would be the major benefit
for aerobatics. It sure seemed to be the ticket for CL stunt.
There seems to be some confusion re the role of high lift slope stabs and
stability. It is difficult for a stab to do it's job of providing pitch
stability in a "hands off" FF situation. For 1 thing it's in the wing
downwash (except for Doug Joyce). Then the fuselage wake can cut it's
effective AR in half, reducing lift slope. Sharp LE also can reduce lift
slope by as much as a factor of 2.
As a model goes toward stall the ideal stab would generate lift (higher lift
slope than wing) faster than the wing.
Why does everyone except Bob White want a low lift slope stab? It boggles
Look at the twin-fins. They have generous AR + tip plates that increase the
effective AR even more.
Another example of successful hi AR stab is Jasco (Zaic) Floater which was
1st model to do 3, 10min maxes and one of the winningest models of all time.
A large wing AR with same fuselage & stab will have a higher tail volume
than same model with it's lower AR wing, yet stability usually suffers as a
result of 1. usually lower wing dihedral angles and 2. low stab AR. ie wing
lift slope increases but stab does not.
For the cost of building a hi AR, blunt LE stab one can prove to themselves
which is the right approach.
No model should stall all the way to the ground, especially with VIT.
SCAT Electronic News - SEN
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