Letters: 04/05

High-Priced Gyros
I just finished your article Mid-Budget Upgrades in the December Aviation Consumer where you again exclusively recommended the Sigma Tek 4300 series back-up electric horizon. This seems like overkill in a light single used for little-but some-serious IFR.

There’s no question that an electric turn-and-bank gyro is completely inadequate for a back-up source of attitude reference in IMC. Unfortunately, we are stuck with this.

I attacked this problem five years ago by installing an overhauled RC Allen 14-volt electric horizon for only $1095, plus a minimal installation fee. It provides complete redundancy for a fraction of what the Sigma Tek costs.

In the Southwest, I spend many hours of flying more than 60 minutes from a suitable IFR divert field so to me, the battery back-up of the 4300 is a worthless feature anyway. I would also strongly question Sigma Tek s claim of 7500 hours mean time between failures.

As a further point of reference, in the 2500 hours and 27 years of flying light singles that Ive done, I have experienced two vacuum pump failures, one vacuum instrument failure and four alternator failures. After the last alternator failure, I continued flight for 4.5 hours by shedding electrical loads and still had enough electric power to crank the engine the next morning and take the airplane to the mechanic.

Brent Smith

Our reason for recommending the Sigma Tek 4300 is not so much driven by worries of airborne failures but the maintenance hassles of replacing one or two cheaper electric gyros. Many owners and shops have complained about short service life of RC Allen electric gyros. If youve gone through two or three of them, it might be time to consider something better.


Wing Covers
I read your article, Death of a Hangar, in the November issue, with particular interest in the segment, Can a Tiedown Possibly Work?

In early 1950, I owned a Fairchild PT-26 and based it at Flying Cloud Airport, near Minneapolis. I could not afford hangar rent, so I procured a set of canvas covers to protect the airplane from weather during the winter and spring of that year. An awning shop sewed them to my order of a light, but durable material that was brownish on one side, white on the other. The material shed water but could breathe, so it trapped little or none. They were attached by cloth tapes about 1/8 by 1 inch, led through grommets and tied.

In the fall, a persistent wind storm battered the area for most of the day with steady winds of 90 to 95 MPH. The PT was tied down and completely covered, wheels chocked. It rode out the wind without incident. More significant, a Vu1tee BT-13 was parked to one side of the ramp without any protection from the wind, however it did have canvas covers on the wings. It too survived the wind without a problem.

It is my observation that the wind tended to raise up the canvas covers as much as 6 to 8 inches above the airfoil surface to effectively destroy a lifting tendency that might otherwise have overturned the aircraft. The PT-26 had some shelter from a hangar about 50 feet upwind of its tie-down spot and its wheels were secure1y chocked. But the BT had only its brakes, which had been locked to hold it and it moved little. As it happened, a new Mooney Mite tied down that day was badly damaged for lack of any wing covering, such as I describe here. Based on that experience, I suggest that a suitable fabric covering over the lift surface of an aircraft parked outside in storm conditions has merit where hangar protection is not available.

Noah S. Rosenbloom
New Ulm, Minnesota


Liquid Cooling
Your January 2005 article, Why Wont Liquid Cooling Fly? I feel that the liquid cooling is safe to fly because the pilot can use it for heating during the winter time and wouldnt have to worry about the carbon monoxide.

Denis Tucker
Houston, Texas

True. But what about hot coolant spraying the inside the cabin when a hose springs a leak?


Light Sport Weight
I think that the light sport pilot category is a good step to help aviation stay strong in this country. What I do not understand is how the parameters were arrived at, specifically, the weight limit.

It seems to me that by excluding the Cessna 150/152 line of aircraft from the LSA category, a person is forced to fly much older aircraft if he wants to own or use an older certified aircraft.

Just about everyone in aviation has some time logged in a Cessna 150/152 and it would not be difficult to maintain proficiency in that aircraft. Is there any process to amend the LSA rules to allow Cessna 150/152s in this category?

Paul G. Olsen
Via e-mail

Russ Niles replies: Not that were aware of. The LSA category determination had less to do with what old airplanes weighed than what new technology could accomplish with the weight of a 150/152.

Dont forget, the goal of LSA is to create a category of aircraft specifically designed for around-the-patch type operations and not for frequent cross-country or business flights.

As we reported in the March 2005 issue, some of the designs from Europe are getting 700 pounds of useful load and 1000-mile range out of gross weights of 1320 pounds. Add a couple hundred pounds, and youve got flexibility for a capable two-place airplane, which wasnt the intent of the rule.

Whats interesting is that the original draft of the rule allowed only 1232 pounds gross weight, which would have eliminated all but a few of the existing certified designs.

Although we have no direct knowledge of this, we suspect the final weight was a saw-off between keeping the new stuff from outperforming the intent of the category and finding a new life for some really great old airplanes.