Traron Squadron

The weather has not been kind to General Aviation and Formation Flying this Spring. NATA had a successful, but smaller than expected Formation Clinic in Sebring before Sun-N-fun. The adverse weather across Northern Florida kept out some who planned on coming (and kept them in when they tried to leave. It took me 4 days to get out of Fla.). Those who didn’t make it to Sun-N-Fun may have the lucky ones, thereby missing the tornado that wiped out a lot of planes. Bob Wall’s T-6 was blown up on its nose, but was ferryable.

The Midwest floods, Texas drought, and fires have been a problem. The CAF hanger in Memphis M01, had 7 feet of water in it when the levee broke. Fortunately the Sea Fury, Ru-10 Extra, Staudacher, Decathalon, and 2 T-6’s were flown out to various local airports. The airport hopes to reopen in mid July, but the hanger will require rewiring and extensive, expensive repair. Unfortunately the CAF had no flood insurance.

Many of you may be going to Oshkosh. NATA will have a Formation clinic at DBQ starting Thursday, 21 July thru Sunday 24 July, with a mass fly out to OSH Sunday or Monday. TRARON members are welcome (see the NATA web site, and be sure to have NATA listed as additional insured on your insurance policy).

This will be the last U.S. Mail Newsletter. From now on the Newsletter will be sent by E-mail and posted on the TRARON website. If you wish to receive it by snail mail, let Julie Smith or me know.

Plan to attend the TRARON formation Clinic at Odessa-Schlemeyer (ODO) before Air-Sho. There will be ground school, Wednesday 5 October at 1800 hours at ODO, with flying Thursday and most of Friday. Late Friday we plan to fly to MAF and hopefully the T-6’s will fly in Air-Sho ( but won’t receive fuel).

Skipper Hyle plans a Formation Clinic August 28 & 29 at Thomason,Georgia. Look for details on the TRARON web site.

QUIZ TIME: Answers from March

What is Maneuvering Speed (Va)?

Maximum speed for rapid (abrupt).

A. Full deflection

B. One control

C. One way

D. One time

E. At max gross weight of your aircraft

Since the elevator has the most authority for G-load, we usually consider it the limiting factor. The “safety valve” for aircraft protection against excessive G-load is the stall (remember that the coefficient of left increases rapidly with increasing angle of attack (AOA) until the critical {stall}AOA is reached, then lift and therefore G forces drop off rapidly).

Maneuvering speed is calculated to allow the stall to relieve the G-load. Since stalling speed increases by the square root of the load factor, we can calculate the new stall speed by multiplying the stalling speed by the square root of the Limit Load Factor (+ 5.67 for the T-6). Thus: VA= V_s X sq. root of the Limit Load Factor, T-6 V_s1= 68KIAS. Vso=58KIAS

For the T-6 VA=68 X sq. root of 5.67

Va=68X2.38

Va= 161 KIAS

Va is also called “cornering speed”, theoretically the minimum turn radius (either horizontal or vertical such as coming down the back side of a loop).

If Va is exceeded (eg. A 7G pull at 180 knots) there is likelihood of structural damage (although the yield load factor is usually 50% above the limit load factor).

Note that the definition is : one control, one way, one time. Use of 2 controls (eg. Pulling and Rolling” increases structural stress, and the general recommendation ( eg. Decathalon and T-28 flight Manuals) is to reduce the limit load factor by one-third.

The Airbus crash shortly after 9-11 resulted from tail separation. In recovery from wake turbulence, full abrupt rudder was applied; followed by immediate full opposite rudder. The second application resulted in structural failure.

Because Va varies with weight, it is not marked on the airspeed indicator. Most GA airplanes have a placard describing it at max gross weight.

Va decreases with decreasing weight. This seems backwards, but can be looked at several ways. The key is Force=MassXAcceleration, or Acceleration=Force/Mass.

In a bar fight when the big guy hits a little guy, the featherweight is thrown (accelerated) across the room. When the big guy hits a bigger guy, the bigger guy barely moves ( is not accelerated) until he cleans the clock of the guy that hit him! The heavier airplane is “the bigger guy” and a gust or sudden control movement doesn’t displace it as much as when its lighter.

Another way of approaching the heavier airplane theory, is that a higher angle of attack is required to maintain level flight because of the extra lift required by the weight, therefore the “reserve” angle of attack between level flight and the stall AOA is less and not as much additional lift can be created to stress the airplane.

The formula for the new (lighter) Va is:

Vanew=VaX sq.root of new-wt./max. gross wt.

Altho the theory and math of Va is interesting and fun to some of us, remember we are flying 60-70 year old airplanes, so don’t fly to the very edge of that WWII Victory envelope. Like some of us, its edges may have weakened and become frazzled over the years!

The Lighter Side:

1. Grant is buried in Grant’s tomb (sometimes the answer is in the question).

2. Will Roger’s observation:

There are 3 kinds of men:

1. The ones that learn by reading

2. The few who learn by observation.

3. The rest of us have to pee on the electric fence and find out for ourselves.

Fly Safe , Morris