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| How
to choose the right airplane? |
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Many
people who call and want information about learning to fly do not
realize until
later that we are in the manufacturing business and produce 4 fantastic
kits. I
am of the philosophy that initially too much information about flying
can be
overwhelming and that potential fliers often need some time to digest
the idea
of getting started on flying lessons. Here is what I look for when evaluating a airplane and mustering my enthusiasm to fly it: Creature comfort This is certainly not the most important thing, however, how safe would one be in an airplane that does not permit full control movement of the ailerons, rudder and elevator. The questions to ask one's self is there enough head room, including helmet if it is going to be registered as an ultralight? If one's head is banging around on first sitting, imagine being in rough air, in a congested control zone, during a flight with marginal visibility. How is the leg room, and what about the long cross country trip, and the pain of a cramp happening during landing? Is it is a tandem seating craft where the rear seat rudder pedals are half way or further past your thighs, and it is a flight where you are wearing your dress pants, while your passenger is dawning grungy sneakers, ripe socks, and was unsuccessful in getting all the dog dung out of his treads before boarding? What is the entry - exit like for pilot and passenger? Unless one is a gymnast, with a gymnast's build, this can get quite exciting. This is especially true after a long flight where one has to get out and successfully make a 350 yard dash to the facilities, because the fly in burritos were extra spicy and rich. In either seat, tandem or side by side, are there things that will be digging into one's hips, legs, shoulders and with hands on the controls are knuckles going to get scraped using them? Is there enough seating room (side by side) that a couple of fatties can comfortably sit in and not feel that they have to exchange vows at the completion of the flight? (This very real problem obviously does not exist for single seat buyers). Structural integrity In today's marketplace the structural integrity of most airplanes is adequate, where as in the good old days there were a lot of new models, some of which were simply built too lightly. I believe that it is better to have an a/c built a little heavier than necessary and not have to worry about it coming apart in very rough weather. The pilots that say it is no problem for them because they only fly in the great smooth stuff, are going to get caught at some point. It always makes me feel better to see strut attach points made of steel or a good healthy thickness of aluminum and the attachment to the strut made with a sturdy looking bolt in shear rather than tension. A 1/4 inch AN bolt on a strut attach point to me looks too light, although its shear strength far exceeds the load that would ever be put on it in a 1200 pound gross weight aircraft. I simply "feel" better seeing a 5/16 or better yet a 3/8 bolt in that position. The additional weight is well worth th e peace of mind, providing the attach point material compliments the bolt. Strut attach bolts in tension always make me nervous because of the number of AN bolts that have flaws in them under x-ray examination. I ask myself how strong the whole wing is and what is going to happen to it in the air under the gust loads that happen. My personal preference is a wing that has a rigid spar in it. The easy way to recognize a rigid spar is to go to the wing tip and (with the owners permission) find a solid part of the wing and push up. If the wing does not bend and as you push up the other wing tip goes down the spar is rigid. If not the wing will flex and in some cases you can hear the leading edge "oil can" if it is made of aluminum. Some spars will be made of aluminum, some wood and some composite. I like the wood and composite because of their strength to weight, but as time goes by there are more possible complications with wood while the composites are only as good as the person that has made them and the conditions under which they were made. Temperatures, humidity and contaminants (oil, diesel, etc.) can drastically change the composite from being strong and safe to looking strong but being totally un-air worthy. It is good to have a look at the ribs and ask oneself if they are strong enough, are there enough of them and if there is a lot of ribs, maybe they are necessary for the strength of the wing. In that case it is good to find out how the ribs are fastened and if the wing depends upon them to do any more than carry the skin it is likely they need to be well anchored. A general spacing between ribs on a fabric craft is 20 to 24 inches, Metal a/c will generally be closer unless a lot of stringers are used. The ailerons are an important item to check for balance, attachment and attach points. Aileron flutter can be a very nasty thing if it is a one of a kind airplane they may be too large, too heavy, and or unbalanced. In an unproven system the safest thing is have them balanced. (When the ailerons are disconnected from the stick they should naturally go to a neutral position. If not counter weights can be added to achieve that neutrality). The empennage (tail section) needs to really be anchored on well. One airplane I saw had the whole empennage break off when the a/c nosed over then dropped back on the tail wheel. The wooden longerons running aft from the fuselage were not strong enough. A wiggle of the fin (tail post) can give some indication as to how sturdy the tail will be. Wiggling the horizontal tail plane out board of the strut (if it is a strut braced tail) gives an idea of how strong the horizontal stabalator and elevator will be. Many airplanes look like the rudder and elevator hinges are inadequate, however if it is a proven system and a system that has been in play on other conventional airplanes and homebuilts for years ones mind can be put at ease. A good question to ask ones self is how strong are the attach points where the cables for the elevator and rudder hook up (some elevators are direct push pull tube while almost all rudders are cable operated). How strong are the cables? A 1/16 inch galvanized cable has a tensile strength of about 685 pounds. If they are used on a rudder, a strong leg can exert almost that much pressure. There is a definite safety concern, whether an older cable, or maybe inadvertently frayed cable will last between inspections - that is the whole reason for thorough inspections - but also a reason to have stronger than minimum parts in the event that deterioration occurs. Virtually all airplanes are critical on their elevator control. This is why trim is essential to cover one's bases. If we stand back and look at all of the control mechanisms as if they were going to fail and start asking the questions "where and how" the problems will start to surface and then we are in a position to make sure that problem will not happen to us. Crash protection There was a time, when I was younger and stupider, that I thought crash protection was only important to the other guys who were not skillful enough to keep from crashing. Lets be clear in aviation circles you never crash, but have incidences. Just like pilots are never lost, just disorientated, and never run out of gas, but exhaust fuel reserves before reaching their intended destination. Living on an airport teaches one that nasty little things happen to pilots too. In the case of a test pilot and friend that worked for Merlin Aircraft when they were in Muskegon, Michigan he ran out of ideas, landing fields, altitude and ideas all at the same time. The Muskegon airport is one of those where there is a few times before sufficient altitude can be gained that any airplane that looses power is in harms way. The test engine decided to fail immediately after take off and since maintaining control and airspeed is imperative the only place to go in control was a thick forest. The pilot landed scratch free, and related to me that the only thing he could do was take the wings off between 2 nicely spaced trees and keep the cockpit intact. Before I get into any airplane I ask myself "what is protecting me?" If it is a tractor, is the frame strong enough to keep the hot engine off my lap and is the fuel in the wings, away from me, or above my legs, above my head or behind me. If things were to go really wrong what are my chances. One does not want to go negative before any flight, but prudence dictates that it is worth looking at options and planning ahead. If it is an open cockpit job I want to know that if I go into a soft field and flip the airplane what is going to hit the ground first - the wing - the vertical stabilizer - or my head. If the stabilizer is not strong enough it may be my head that props up the ship after the flip anyhow! If the craft is a pusher I imagine what would happen if I had to go into a cow pasture and hit a ditch, or cow, or tree. A good look in the front end of many will show a marshmallow skin of 1/16 fiberglass followed by my feet, legs and butt. That means that my aging carcass will soften the blow for the rest of the airplane. Sort of like the last thing that goes through the mind of a bug hitting the windshield. How well is the engine attached in that pusher, not only engine mounts, but attachment to the airframe. Airplanes are built to fly and the mount may be completely adequate for all modes of flight and landing but, "I wanna know how low I will have to duck to miss the 96 + pound projectile that comes hurling at me." Flight Characteristics When someone is going to plunk down a bunch of cash for a ride in the sky the above factors are of paramount importance to comfort and safety, however they mean nothing if the skyship is a lousy fly. I think that, just like in most things we do we all want the same things. We want to live the dream that has been ours for a considerable time. Much anticipation has led us to the point of purchase and we want the very best value for our money. When we zero in on a particular airplane we may run into many people that have the same machine and they give it a sterling review. At this point we must recognize a factor of human behavior. When someone has made a decision and a purchase, in most cases, they will defend it even it they have found it to be a wrong one. Case in point on our airport. An very respected individual purchased a new airplane based on the fact of having a similar one years ago that he was happy with. The new one did not handle nearly as well as the old one - and would he admit it - no, not a chance. His pride stood in his way, even though he admitted to a few of us that he was unhappy and was about to make a change. Some pilots will say that their airplane flies great. Compared to what? If they say that it flies like something that we are familiar with we will have an idea of what they speak. If their experience is only in that type of airplane, do they really know what great or not so great mean regarding flight charactistics. A decision of an airplane should not be based on the flight reports of magazine types because when was the last time you ever saw a bad flight report. The writers would very much limit the airplanes they get to fly and write about if they said anything bad. Jim (Zoom) Campbell of U.S. Aviator Magazine is the only writer that I have ever seen that tells it like it really is, and he has got himself into a lot of trouble over it - lawsuits and even death threats! If carefully read though, interesting comments come through. In regards to an airplane I feel flies very unstable an Internationally respected writer wrote of its flight charaistics as "quite pleasant." What he didn't say on its flight characteristics in the rest of the article speaks louder than what he did! A test flight is an excellent way to see if the saddle fits. Be suspicious of demo flights where you are told to keep your mitts off the controls or ones in tandem airplanes where the demo pilot has to sit in the normal pilot seat and you, the perspective buyer, have to sit in the passenger seat. All kinds of excuses can be used like "we only have brakes in the front". If the brakes are that important in their light airplane, maybe that is a sign of instability right there, unless there is a howling cross wind. When at the controls see how the plane flies ailerons only. Also check it out and see how it flies rudder only. If it is a perfectly calm morning or evening the airplane should fly both hands and feet off. The best time to check the airplane out is around noon to at least get a few thermal bumps to see how it maneuvers through them. Buying an airplane is not a science, but requires a certain amount of application of scientific methods. Before buying, hang around small airports and take a good look at how conventional aircraft are built, looking at the bolts, fittings and hinges, etc. Most pilots are a wealth of knowledge and are happy to tell you what they like best and least about their airplane. Valuable information. And the search for the "perfect" airplane goes on. |
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