Each Best Speed For Your Airplane Serves A Purpose

by Pete Schoeninger
Published in Midwest Flyer – October/November 2020 issue

Q. Could you explain “best loiter speed” and how I can find it for my airplane? Also, where would I find information on “best power-off glide speed?”

A. Best loiter speed is the speed of lowest fuel burn per hour, not per mile, in level flight, which usually occurs at a very low airspeed. This would be a handy bit of knowledge if you ever have to circle an airport while snow removal crews finish clearing a runway, or if someone landed gear up ahead of you and it will take some time to remove the damaged aircraft, or you are waiting for fog to burn off, etc. If you can’t find your best loiter speed in your airplane’s Pilot’s Operating Handbook, Airplane Flight Manual, or Owner’s Manual, the “best angle of climb speed,” which should be readily available, will be close to your best loiter speed. If you can’t find your “best power-off glide speed,” use your “best rate of climb speed.”

Q: I just bought a used 1975 Cessna 182 from an estate. It has been sitting a few years. The maintenance records are very sparse, and the mechanic who used to maintain it has passed on. I could not find any record of any Airworthiness Directive (A.D.) compliance. The shop I have hired to perform an annual inspection has warned me that it will take many hours of research to compile an A.D. summary from scratch. Will I have to do this at every annual inspection?

A: At every annual inspection, A.D. notes have to be checked and if any are found outstanding, they must be complied with. Many A.D. notes are applicable to after-market equipment, such as fuel caps, mufflers, alternators, etc. So, an A.D. note could be issued against the after-market manufacturer, but they will also be shown as possibly affecting models that could have the device installed.

Here is a method some mechanics use which adds clarity and saves a lot of time with future inspections, but takes some time to create initially: 1) Make a list of A.D. notes that do not apply to the airplane, because they are not installed. List the date inspected and note “not installed.” 2) Make a list of A.D. notes that DO apply to the airplane, but are one-time compliance items, such as change markings on oil temp gauge. Note the date, hours and who inspected the marking change. 3) Lastly, make a list of recurring A.D. notes, showing the A.D. number, date and hours of compliance, and how complied with, and by whom, and when the next inspection is required. An example is old Cessnas may need their seat tracks inspected every 100 hours of use, or at every annual inspection.

Q: I just read that airplanes with a high “aspect ratio” glide better than low aspect ratio wings. Can you explain and give an example?

A: Generally, that is a true statement. Aspect ratio is defined by wingspan divided by chord. For example, on a Piper Tri-Pacer, with short, fat wings, the aspect ratio would be about 30 ft/5 ft = aspect ratio of 6. But a sailplane with 50 ft wings and a 4 ft chord would have an aspect ratio of about 50 ft/4 ft = 12. Tri-Pacer owners will tell you that it is a fine airplane, but the glide path is pretty steep power off. Sailplanes (remember, high-aspect ratio) on the other hand may glide as far as 40 feet for every foot of altitude loss.

Q: I recently purchased a hangar on a private strip from an estate. Inside the hangar are two-gallon cans with what smells like gasoline. Can I dump them into my 1966 Cessna 172, which is approved for car gas, as well as aviation gas?

A: Don’t! If you are not sure of the origin, and purity, of your newfound gas, I would not consider using it in your airplane. Perhaps the field owner may want to use it in some field maintenance machine like a gas-powered tractor. But if it is 100LL, even burning it in anything but an airplane is a no-no. Anticipating your next question…do not even think about putting 100LL into your road vehicle. Not only is it illegal, but it will booger your catalytic converter, an expensive item. Note: Be sure to dispose of any old fuel at a waste disposal center, and not in the soil.

Q: Thinking ahead to winter with my new IFR rating in my pocket…experienced pilots warned me about the decrease in climb capability of even a bit of ice on my wings and prop. They tell me that in the winter, often there are clouds from 3,000 to 4,000 feet up to perhaps 7,000 to 8,000 feet. In the summer, it takes my 1985 Cessna 172 about 10 minutes when fully loaded to climb from 4,000 to 8,000 feet. Won’t it climb better in the winter given cooler temperatures?

A: Yes, your airplane will perform better in the winter, providing you have no ice onboard! An airplane trying to climb through stratus clouds to reach clear skies could run into non-forecast light rime ice. (Remember to turn on pitot heat before entering clouds.) As ice accumulates on your wings and prop, your climb rate might slow to zero before you get out of the clouds at perhaps 6,000 to 7,000 feet. If you get into that situation, get out of there as quick as safely possible, probably descending back to VFR below. A Cessna 172 is a fine airplane, but it is not certified for flight into known icing for many reasons, and it does not have excessive amounts of power to climb while ice accumulates. In these situations, a Cessna 182 or a twin are much better choices because of their better climb rate.

Q: I called my shop manager and asked for an hour of his time to discuss maintenance on a Piper Lance with my brother, who is considering buying one. We met at his shop at 9:00 a.m. and got lots of good information in an hour discussion. However, I was astonished that at the end of the month my statement for hangar rent, fuel, etc., included a one-hour charge for consulting at $90, his hourly shop rate. I was very upset at this because he did not do any maintenance on an airplane. Who is being unreasonable – my shop manager or me?

A: You got what you asked for (maintenance information on a Piper Lance). Pay the bill, period. An hour of a professional’s time at his facility is how he makes his living. He has massive overhead expenses that is paid using his expertise and knowledge. Someone has to pay for these things, and it is you, the customer. Would you ask your CPA for an hour of his time for free? Or a plumber, or a doctor? The answer is no!

Q: A friend emailed me a picture of a Cessna 180 sitting on a sandy narrow road in Alaska. Supposedly the straight stretch of the road was only 800 feet, with about 30 ft trees at each end. Would you attempt to operate out of that strip if lightly loaded?

A: My Cessna 180 experience is very limited, so  I asked a friend who has owned a Cessna 180 for many years and has massive flying experience (several years of crop dusting, and as a chief pilot for a Fortune 500 company flying Gulfstreams). Would he attempt to operate his airplane in this place I asked? He is not a man of many words, but when he speaks, I listen. His answer was “Nope!”

Q: A year ago I sold my normally aspirated 1978 Piper Arrow. That was a mistake! Now, I am looking for a similar one to buy. I have found one with nice avionics, a 35-hour engine (turbocharged) at what seems like a reasonable price. Recently (3 months ago), the aircraft had an annual inspection and its overhauled engine installed. I am tempted to skip the pre-purchase inspection because the engine is freshly overhauled, and the airframe recently had its annual inspection. What do you think?

A: Unlikely, but possible that many terrible things could happen to an airplane in 3 months/35 hours. Also given that the turbo-charged engine is more expensive to buy and operate, you should hire a knowledgeable party to look at the records of the overhaul. For instance, were accessories, such as the turbo charger, replaced or rebuilt, prop overhauled or not, etc.? A thousand bucks on a good prepurchase inspection would be mandatory in this situation and would be money well spent.

Q: I recently bought a farm in rural Minnesota. Part of the appeal is that the land is quite flat. I am looking at an alfalfa field, or pasture, as a possible landing surface for my Cherokee 180. Both fields are a half-mile long (about 2600 feet) and I will usually be flying solo. My question to you is, how long can I let the alfalfa or grass get before their length affects safety and performance?

A: Remember, all grass fields have more drag on your tires than pavement. As a former alfalfa farmer and cow pasture pilot, I can give you two reasons to use the pasture, not the alfalfa field if they are both similar in size and flatness. Alfalfa, clover and other broadleaf plants, can be pretty thick and sturdy, and cause you lots of drag, even at a relatively short height. Alfalfa has more cash value than pasture grass. Pasture grass will probably have less drag than alfalfa of the same height. But in either case, you should not try operating when the grass is as high as the middle of your wheel or higher to prevent it from wrapping around your axle and causing many problems. Cutting your runway frequently will cost you some lost income if you elect to use the alfalfa field, and less if you cut the pasture. Tailwheel airplanes with big tires can operate in taller grass, but your tires are relatively small. Keep the grass short and enjoy the joy of flying from your own farm!

EDITOR’S NOTE: Pete Schoeninger appraises airplanes for estates, divorces, and partnership buyouts. He is a 40-year general aviation veteran, starting out as a line technician as a teenager, advancing through the ranks to become the co-owner and manager of a fixed base operation, and manager of an airport in a major metropolitan community. For aircraft appraisals, contact Pete at PeterSchoeningerLLC@gmail.com or call 262-533-3056 (peterschoeningerllc.wordpress.com).

DISCLAIMER: The information contained in this column is the expressed opinion of the author only, and readers are advised to seek the advice of others, and refer to aircraft owner manuals, manufacturer recommendations, the Federal Aviation Regulations, FAA Aeronautical Information Manual and instructional materials for guidance on aeronautical matters.

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