Over the Weather

Great write-up on aviation weather web sites by Bob Fritz in the May 2008 issue. However, he left out my personal favorite freebie, www.runwayfinder.com.

Dave Parsons

On Ethanol

I enjoyed Dave Martins article on ethanol in Aprils KITPLANES. A very pertinent topic. It reminded me of something I read last week. If all the corn grown in the U.S. was converted to ethanol, we would cut oil imports by 3.5%, the same amount that we would save if all the vehicles on the road had their tires properly inflated. Robbing from our food chain may not be the answer.

Skip Pardee

Der Zulu Ist Gut

I have seen your LightSPEED Zulu headset review by Jack Cowell, [which was also published on our sister site, AvWeb.com]. As an early user, I agree with most of what was said. I have two negative points about which the readers should be informed.

1. The Bluetooth is a feature which I would like very much, but it is not compatible with my newer cell phones from Sony/Ericsson (K750i and K800i). With the older T68, it works fine. I contacted LightSPEED, but we could not solve the problem yet. It might be that cell phones in the United States are more compatible.

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2. I recently experienced an over compensation in the very low frequency range (below 50 Hz). After moving the headset, it went away. This was in an American Tiger AA5B. I had similar problems with the Bose in the Piper Cub.

For noise cancellation and clear voice, I think the LightSPEED much better than the Bose, which I have used for the last three years.

Hermann Spring
Head of Training,
Motorfluggruppe Pilatus

From the Snakes Mouth

I thoroughly enjoyed Barnaby Wainfans well written discussion of pitch sensitivity in the January issue. As an initial cadre “Viper Pilot” at Hill AFB, Utah, I was particularly interested in the discussion of the growing pains in the early F-16 fleet.

The engineers at General Dynamics had paid close attention to the “rules” regarding G versus stick force when the system was designed; the 9G limit was reached with about 38 pounds of stick force. The 300-per-second roll rate was achieved with about 15 pounds of lateral stick input. The “complaints” came about when we would come back from an air-to-air mission with our stick arm literally burning from extended high force inputs. The engineers wired recorders into the system to measure actual stick forces and were surprised to see pitch inputs of up to 200 pounds!

The basic problem, as Barnaby correctly pointed out, was the system had absolutely no form of feedback to indicate the pilot had made a “max command” input. The solution was adding a calibrated flexible element to the base of the stick and a “collar” near the point where the stick emerged from the console resulting in approximately 1/8 inch of movement at the top of the stick when “max command” force was applied. The pilot could now sense a “stop” in the stick and would know that additional force was unnecessary.

Over the years, additional refinements were made to the control laws regarding the blending of angle of attack, G load, airspeed and aircraft configuration (the “takeoff and land” control laws are quite different from the “up and away flight” laws) to improve aircraft handling in each regime. The speed at which the control system shifts from one set of laws to another is what got our YF-22 pilot…

I enjoyed the memories!

Larry Danner

The Great Tool Hunt

In the May 2008 issue of KITPLANES, Home Machinist Bob Fritz included a photo of a mystery wrench and asked folks to write in with identification. The response was a bit surprising in that this introduction-to-machining series of articles is being read by a lot of tool and die maker experts.-Ed.

The tool in question is a “hook spanner” or just “spanner wrench.” I ran a saw and tool grinding shop for 33 years. Nearly all our upright grinders (West German) used a “spanner wrench” to loosen/tighten the “ring” nut that held the grinding wheels to the spindle. They were marked in mm (millimeters) relevant to the outside diameter of the spanner nut. Yes, there were adjustable spanners, hinged midpoint, so that they could “span” several different sized nuts.

Roger Mathews

Please inform Bob that the name he is looking for is “spanner,” as in hook spanner, pin spanner, etc. When in doubt or looking for corroboration in tool naming conventions, I typically look at MSC and Snap-on.

Hal Preston

I was born in Chicago, in 1926, to German parents. My dad was a tool and die maker for all his life. I was lucky to have a machine shop in the basement of our home. I truly enjoy your articles. Some things don’t change with time. I have a tool very similar to the one on page 53. The handle is cast with the following information:

J.R.WLLIAMS & CO. BUFFALO, N.Y. U.S.A. on one side and 471 3/4-2IN. ADJUSTABLE SPANNER on the other.

It is painted in black enamel. I have had this tool for at least 60 years. My tool is as yours except that the pivot pin is flush with the handle.

Frank Weiss


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