The Leading Edge
The newsletter of the MIT Soaring Association
December 1997
The original postscript version of the newsletter is available here.
Annual meeting: Plan on attending this year's annual meeting sometime in February, it'll be one great party.
New certificates: Phil Gaisford passed his commercial flight test on December 6. Congratulations, Phil.
New chief instructor: John Wren has been appointed our new chief instructor by the board of directors. Steve Moysey, our former chief instructor, has stepped down due to time constraints. Thanks to both John and Steve.
New diamond and lennie pins: Mike Baxa had an exciting wave flight at Franconia at the end of October while the rest of the club was at Sugarbush. He writes, ``Good news for Mikie. Just learned that my recent wave flight got me a diamond and a lennie pin for flying over 25,000 feet. It took quite a few tries. Life is good!''
New gliders: Jim Tsillas is the new owner of a PIK-20B, which he flew at Sterling for the first time on December 6. Steve Sovis and John Wren are the new owners of a PW-5, which they flew at Sterling for the first time on December 13. John drove down to Texas to pick up four PW-5s for local pilots, and wrote about his incredible trip -- including his ``interview'' with the Ohio state police -- on the World Class Soaring Association home page: go to www.wcsa.org and follow the link ``The Great Retrieve'' to see narrated pictures of the trip. Be careful to type ``wcsa'' and not ``wsca'' by mistake, or you will find yourself at the home page for the Western Shrine Clown Association.
Engagement: Jim Tsillas and Debbie Najjar have announced their engagement to be married in the spring of 1999. Jim says that Debbie loves to fly and has had several rides as a guest at Sterling and at Sugarbush. Attaboy, Jim!
Fred Ernsting: John Wren says that former member Fred Ernsting (fgernsti@eos.ncsu.edu) was in town during November. As Fred wrote in the last newsletter, he is working at a large flight school in North Carolina, and apparently he is also managing certain sections of the company involved in purchasing and selling aircraft. His company had purchased a Katana trainer at Bedford and he was sent up to retrieve it, but he only got as far south as Mansfield before he got socked in and had to wait out the weather.
Al Cangahuala: There is a rumor that former club member and board member Al Cangahuala (laureano.a.cangahuala@jpl.nasa.gov) was on the television game show Jeopardy during November for three days, and was winning on the first two days and lost only in the final round on the third day. Amazing if true. Could this mean his career is in jeopardy?
Varun Puri: Varun Puri (varunpuri@aol.com) flew with the club for a short while -- coming to MITSA after instructing at the Air Force Academy in Colorado Springs -- and he recently made contact with the club: ``I had a blast flying with the club, and I enjoy reading of recent events in the Leading Edge. I'm in the middle of USAF pilot training right now, and I thought some folks out there might be interested in what it's like. If you are interested, I can send some pictures of the T-37, the trainer I'm in right now, as well as the T-38, which I start flying in February. In a nutshell, pilot training is an awesome experience. I can't believe I get paid to do this! The days are long, but I get to fly a twin-engine jet trainer solo, doing loops, Cuban eights, Immelmans, you name it, all at 250 knots! And we just started formation flying. Try a lazy eight at 220 knots three feet from another plane--wow!! I'll graduate from here next August, then compete for an assignment into an operational unit, though I don't know right now what aircraft will be available. Hope everything's well for you, and happy flying!''
A stolen joke: What are the only three phrases a flight instructor needs to know? First, ``More rudder!'' Second, ``I've got it!'' And third, ``Can you pay me today?''
These minutes have been edited for publication in the newsletter. --Editor
November 6, 1997
Directors present: Bruce Easom, Jim Emken, Phil Gaisford, Steve Glow, Al Gold, and Carl Johnson. Also present: Bob Fletcher (via speaker phone) and John Wren.
New chief instructor: Steve Moysey has run low on time and cannot continue as chief instructor. John Wren has offered to take over the position. The board discussed the matter and voted to give the position to John.
Finances: MITSA has been loosing money this year for two reasons: the lack of instructors causing many low-time students to leave the club (and thereby lower both dues and tow income), and the unusually expensive maintenance on both the gliders and the tow plane. We have resolved to watch our spending as much as possible and will attempt to recruit more instructors for next year.
Maintenance: Most of the gliders need waxing before the winter. Jim Emken has taken the audio variometer out of 117 and has sent it back to Cambridge for repair. Several tie downs still need to be replaced: the tie downs for the 1-26, one of the tie downs for the 1-34, and the tie downs for one of the L-23s. There are some trees around the tie downs which need to be trimmed back or removed. Carl Johnson will bring a saw to the field the next time he goes and take care of it. Jim organized a work party this past month to help weigh the gliders. Jim will publish the new weight-and-balance numbers after they have been signed off by the A&P who did the actual weighing. The throw in the control rigging of 118 seems to be slightly off balance causing it to want turn slightly. Both L-23s should have their tail wheel grommets checked and replaced if necessary.
Safety board: John Wren as chief instructor has organized a safety board which will be making suggestions as to how MITSA might improve its operations. The safety board consists of: Mike Baxa, Ian Clark, Jim Emken, Phil Gaisford, Andrew Watson, and John Wren.
Blue Book: Bruce Easom has put some time into updating the club operations manual (the ``blue book''). He handed out rough copies for us to review and update as necessary.
Sterling field update: Bob Fletcher has continued his discussions with GBSC, and they expect to be making a decision sometime around the end of the year. Their club will likely either be moving north to New Hampshire or joining us at Sterling. Bob has also looked into starting an airport from scratch, but it sounds like the paperwork would be difficult and expensive. Our best bets right now look like Sterling or Norfolk. Even if GBSC decides to move north, it seems likely that we will pick up a number of their members who are not willing to make the long trek each weekend.
These minutes have been edited for publication in the newsletter. --Editor
December 11, 1997
Directors present: Bruce Easom, Phil Gaisford, Al Gold, and Joe Kwasnik. A number of directors were ill this evening.
Annual meeting: Following last year's resounding success, Carl Johnson was nominated to organize the next annual meeting, with a suggested date of sometime in February.
Maintenance: Minor repairs to the tow plane will be carried out at the next annual due later this winter. Bruce Easom has placed the material needed for the replacement of the remaining tie downs in the MITSA office. Bruce wants to attempt to wax the gliders again soon, a task that has been impossible due to weather. Bruce has also visited the Fort Devens commerce center and inquired about space for rent for glider maintenance. They had only office space, so we don't know yet how to get access to the hangars.
Gift certificates: Joe Kwasnik has sold six or seven gift certificates for one-day memberships. DOs: please note that the certificates are prepaid and bear Joe's signature, and please collect them and send them to the treasurer when they are redeemed at the field.
Instructor candidates: Phil Gaisford has obtained his commercial certificate. Bruce Easom is enjoying the ``Fundamentals of Instruction.'' Phil will interview Jim Emken, Carl Johnson, and Mark Tuttle about their status.
Blue book: Comments on the blue book circulated by Bruce Easom last month include the need to add information about the golf carts. Phil Gaisford will contact John Wren for input from the chief instructor. Tow procedures are currently under review, and will be included in the new blue book.
Club office: Al Gold may have a lead on a construction trailer from the ``Big Dig'' that might serve as a new club office. Al will contact Mark Tuttle for information on documentation of the club's nonprofit status, which will be needed in the case that the trailer owner is willing to make the trailer a charitable donation to the club.
Next meeting: Thursday, January 15.
Safety: First...Middle...and Last
Mountain wave flying is like many things in life: The up-front work determines the outcome!
Recently one of our up-and-coming management stars at the company scheduled a meeting with me. She does not report directly to me and I could tell she was nervous. We sat down and she conveyed she wanted my advice with respect to her career. I asked her what her long-term goal, was and after a long pause and stumbling over her words she said, ``Mr. Baxa, someday I would like to have your job.'' In previous positions I have had similar inquires, though more diplomatic, but it always makes me chuckle with admiration for the motivation and drive. I asked ``Are you willing to set tough objectives on your way to your goal, to stay focused and make this one of your top priorities?'' She said yes and we got down to the subject at hand.
So it is with mountain wave flying, which is one of the most exhilarating, challenging, and rewarding aspects of our sport. However, one doesn't just wake up one morning and say, ``Gee, I think I'll go fly the wave today.'' It takes a commitment to learning, developing the skill set, and extensive preparation. The following is intended to give the private pilot looking for other challenges something to think about. Perhaps, it might get you interested enough to learn more while relaying some practical and safety oriented insights into high-altitude flight. It is not intended to be a comprehensive discussion. It is far from an authoritative report. And, I am far from being an expert. Again, it is to generate club member interest and, hopefully, interest in a club encampment at a wave site. But first, the necessary qualifiers need to be stressed.
Mountain wave flying requires a different set of skills, knowledge, and a building block process of experiences. Without these you are putting yourself at risk. I suggest a pilot should have a private license; have silver distance cross-country experience; have at least 15 hours of direct thermal experience and 15 hours in ridge flying; and have a high level of common sense and good flying judgment. Mountain terrain is steep and treacherous. There are usually few, if any, off-field landing sites. The conditions for good wave call for strong winds, and where there is wave there is rotor (imagine yourself on a roller coaster during an earthquake). Safety becomes more than a state of mind. It must drive every decision. Mountain wave and ridge flying can be safe and fun, but you have to ``pay your dues'' with the up-front preparation. Earning that gold, diamond, or lennie pin can make it all worthwhile, not to mention the breath-taking view and feeling of personal accomplishment.
You should refer to other written sources for a better and more thorough discussion. My experiences are at Mount Washington in the Presidential Mountain Range next to Gorham, New Hampshire. A few highlights would include the following: Mount Washington stands 6,300 feet msl. The wave will generate from any wind direction, but generally works best with a northwest or west wind at 25 mph or more. Winds at 60 mph on top will take you to 25,000 feet msl or greater. You can be towed into the wave to about 5,000 feet agl or ridge/thermal into it if experienced and confident in your abilities (if you miss and end up on the lee side with the violent rotor, you'll have some memorable experiences). Once in the wave, it is a smooth elevator ride up but requires flying concentration. Wave can extend a 100 miles or more downwind, but at Mount Washington the primary wave is geographically concentrated. Towing may avoid the rotor, but there are other mountains that generate wave and it is not unusual to encounter rotor, wind shear, and cross-shifting winds during flying and landing.
Start now: read books, articles, and everything you can get your hands on; talk to any of the MITSA instructors on this subject; raise the issue with other wave pilots and ask them to share their experiences; begin getting and fine-tuning that needed thermal and ridge experience; and start putting together the checklists we will discuss and making preparations.
You need a glider with an oxygen system. The oxygen system needs to be checked out and the oxygen tank filled. Check with the O2 supplier, but today's medical oxygen has no moisture and is safe (moisture can mean something freezing and having a system failure). FAR 91.211 tells us we should go on O2 at 12,500 feet msl if we are at that altitude for more than 30 minutes. At 14,000 feet msl it is time to go on oxygen. I personally prefer nasal cannulas over masks but a recent FAA decision does not approve the nasal cannula for flights over 18,000 feet msl so we must go with the mask (the disposable masks are very affordable at $5 to $10 and can be reused). A Continuous Flow System is good for flights to 25,000 feet and a Diluter-Demand System (automatically adjusts oxygen-to-air ratio to flight altitude) is good to 35,000 feet. In New England, it is unlikely you will get over 35,000 feet, but it is possible assuming you have ideal conditions and an FAA wave window opened to that altitude. You would then need a Pressure Demand System which forces O2 into the lungs (at this altitude other equipment is also necessary including experience in a pressure chamber). Of course, you want a thorough O2 system checklist made up and handy. An oxygen system failure or oversight may cost you your life. Then again, so may a stall on final at our local airport on a calm day. We need to recognize and keep ``risk'' in its proper perspective.
Hypoxia is something you do not want to mess with. Being a non-smoker and in good physical condition is a big plus. Even so, at 15,000 feet msl with no O2 , you risk becoming incapable of decision making or even unconsciousness. In the excitement of any flight at any altitude you also risk hyperventilation (result of rapid breathing) which can upset the normal CO2 levels in your body. Breathing normally is very important. At 25,000 feet without oxygen you have two to three minutes of useful consciousness, and at 30,000 feet you have 45 to 80 seconds before passing out. At this level you want to carry a back-up emergency hand bottle of O2 like the parachute jumpers carry. This will give you the time to get down to a safer level if you have a system failure. I also make it a practice to check my fingernails every five minutes. If they start to turn blue or purple, SOMETHING IS WRONG, GET DOWN NOW.
Altitude duffel bag: I have a special bag ready to go. It includes my wave clothing and gear. Remember that at 25,000 feet msl it is minus 35 degrees without the air vents open. Wear layered clothing as the air between the clothing layers further insulates the body from heat loss. My top layer is a thermal work coverall-style jump suit you see at discount stores ($40 to $50). It has front zippers on top and the bottom for greater ease in the ``relieving'' process and many zippered pockets that are handy for carrying things. My outer socks are heavy wool socks. As an aside, the feet are always the first to turn cold, and you should be continually moving your toes to stimulate blood flow/warmth; if your feet sweat, put on dry inner socks before you fly; and the duck-hunting battery-operated socks do not work. The batteries go dead after awhile in the cold and it is not worth the hassle. Warm thermal gloves are a must and so is a wool ski cap or pull-over face mask. The face, head, and neck are very well supplied by the venous and arterial blood vessels. Thus, this area is the greatest source of heat loss. This is why divers where the head and neck hood as part of their wet suit.
You may be dressing in this garb at 70 degrees on the ground, so don't get dressed an hour before your flight. I also like to carry in my bag a roll of clear plastic wrap. I will use a sheet of it taped on the inside of the canopy to prevent fogging and frosting of the canopy (the air layer prevents frost from forming and you can't see to land if you have frost). Regularly opening the air vents will help to defog the canopy, but eventually you can't stand the minus 50 degree air flow or wind chill and the vents cannot always keep up with the fog rate. Never try to hand wipe any frost forming. It only makes matters worse as the heat from your hand temporarily melts the frost before it freezes again.
Extra water bottles: I like to stick extra bottles under my legs where they won't bounce around and crack a canopy or hit me in the head during turbulence. Dehydration during long high-altitude wave flights is another important concern. The air is cold and dryer at altitude, you are breathing dry O2 , and you are sitting in very bright and intense sunlight. You must continually force fluids. Oh yeah, don't take canned or bottled sodas with you unless you like flying wet. This is a not-so-great way to learn first hand about altitude pressure differences.
Relief system: What goes up comes down and what goes in comes out. Unless yours can reach the canopy vent hatch, plastic zip lock sandwich baggies filled with one-quarter diaper stuffing is a cheap and effective relief system. Take plenty of baggies with you if you are planning a long flight. It is also wise to practice your ``relief'' technique during your local flights before attempting cross-country or wave flying. Many new pilots have real difficulty in relaxing enough in a semi-reclined position while flying. It is an acquired ``skill'' but necessary to master! Being unable to relieve yourself, can become a safety concern if you are trying to concentrate on landing while in extreme pain, especially in situations demanding heavy cockpit duties, such as severe turbulence, off-field landings, etc.
Fully-charged battery and barograph ready: Put a full and fresh charge on your battery due to the cold environment and try to keep your transmissions to a minimum to save power especially if you have other electronics you are dependent upon. Have your barograph papered, initialed, and so on to save time before the launch. This winter start studying the SSA altitude badge requirements.
Survival kit: It is hard to believe we do this altitude thing for fun! Mountain flying or ridge running in the Northeast usually means steep mountainous inclines, trees everywhere, few landable fields, sparsely-populated areas, potential for snow or freezing rain, and more trees. If the unthinkable happens and you are forced to do a tree landing in a remote area, you will need a survival kit. These things we fly can be difficult to find in a vast wilderness, and it could take days before a rescue crew could be on site. The following items are my suggestions, but add as you think appropriate: whistle (you can hear a whistle far further than a voice and it saves your voice for later screaming, ``Where the hell have you people been?''), metal signal mirror (they don't break), knife, aspirin (if you go down, you will have had a rough day!), first aid kit (make your own up as it will be cheaper and better), waterproof matches, tube tent, water, granola bars (they keep forever), at least two highway flares or a flare gun, and hand compass. An ELT (emergency locator transmitter) is optional on my list. There are pros and cons, such as is anyone going to respond when it goes off.
Other stuff: Sunglasses are a must. Chewing gum helps to prevent ears from plugging up during rapid ascents and descents. Make sure you have a watch on as you can easily lose track of time in this new and somewhat exotic environment.
The wave window: Plan to go to an operation in the mountains that already has an FAA-approved wave window. FAR 71.33 discusses class A airspace. In essence you do not fly over 18,000 feet msl without a wave window opened by Control, namely Boston Center. If a window has already been established, all that is required is a phone call 1-2 hours before your flight. Control will dictate when the window will be opened and when it will be closed along with maximum altitudes. You should always radio or call once done with your flight, so they can close the window. Remember, gliders are invisible to radar and we do not carry transponders...yet. You along with other aircraft need the protection of an FAA wave window where the traffic is rerouted around you.
As a side note, it should be stated it is extremely difficult to obtain an established and approved FAA wave window. Several years ago and over a six-month period I tried to get a window over Mount Greylock. After numerous letters, forms, diagrams, phone calls, and being shuffled around, it was finally denied. The weekend jet warriors would like to buzz the mountain at low altitudes (and you think we have traffic problems) and I speculate they didn't like the idea of us playing in any upper air space.
Area check ride: Before flying in any unfamiliar area or at a new airport, you must take a check ride. Here you will learn the landmarks, landable fields, local airport procedures, area weather phenomena, etc.
The night before the flight, get a good night's sleep.
Have your ship rigged and ready well before the flight: In the excitement to fly it is easy to overlook things. You will have several checklists to go through. You will also have the barograph and its pre-documentation. Give yourself plenty of time and a chance to double check everything. Always make sure your ship is well-secured on the ground. Blow-overs should always be a concern in any high wind area.
Talk to the tow pilot: He will know where the wave is and how to avoid the rotor. You need to tell him what tow speed you want. You also have to work out signals with him if he doesn't have a radio; for example, have him rock his wings when you are in wave. Again, after you get more experience, you will want to try thermaling or ridge lift to ``jump'' into the wave from a lower release altitude. It is great fun and a real challenge. The tow pilot may also have access to current weather information. At Gorham Airport they call the weather station on top of Mount Washington to get wind speed, direction, and conditions. Once sitting around at 10 in the morning during light 5-10 mph ground winds, I asked the tow pilot if he thought the winds would pick up. He called the weather station and it was already blowing at 45 mph on top. I had a seven-hour wave flight on a day I thought was going to be low-level thermaling at best. Conditions are always different at altitude.
Eat before you go, but not to heavily: You will need internal fuel for the cold climate you are about to enter, but don't over do it. It takes a lot of blood for digestion and you want it circulating in you head, not your abdomen. Also, some people suffer with gas pains at altitude, given the expansion of the bowel gases. I have never had a problem but one should probably watch the kinds of food eaten before an altitude flight.
The tow may or may not be normal. It is possible it may be a bit of a wild ride depending on the conditions and the tow pilots ability to out-guess the rotor. Do not necessarily jump off the first time the tow plane takes a leap up or down. You might also have ongoing slack line problems if the turbulence is severe. Mountain turbulence and conditions can vary from hour to hour. The tow for the guy ahead of you may have been uneventful but you might find conditions different. However, if you ever lose sight of the tow plane, have slack line that threatens the safety of either aircraft, or you sense you are flying in conditions you are not prepared for, then release immediately, assuming you are at least 200 feet agl after take off. You should always concentrate and anticipate on any tow and be prepared for quick corrective actions. It might be a good idea to practice slack line removal with an instructor if you think this might be a problem for you.
Upon release in wave, do not make an exaggerated bank to the right like you have been taught and trained. Watch the tow plane and tow rope as he dives to the left to assure you have a clean release. A ninety-degree turn can find you out of the wave and a significant distance from your release point unable to penetrate back and up into the wave where you were originally. Don't forget to notch your barograph and don't assume it will be easy to do! On a recent wave flight to 25,000 feet msl, I released in well over 1,000 feet per minute climb (the vario was firmly pegged and didn't budge for 5-8 minutes). It took me two tries to get a good barograph notch. As a side note, if you have never used a barograph, it is time to learn and practice the technique for notching (the mark that indicates release from the tow plane and your probable low point).
The climb will be smooth and quiet with a little background sound of the wind. A good tape and seal job on the ground will pay off in the wave. After notching the barograph, turn your attention to finding a good ground landmark below you. Do not try ``exploring'' the wave or doing any maneuvers initially. Wait until you are higher or you need to. Once you have your landmark, focus on getting your flying speed to zero ground speed (becoming stationary in the sky) and keep your nose directly into the wind. This may take some time, but you will become proficient with practice. Wave flying requires a high degree of mental concentration and small control inputs.
If at altitude and you are blown out of the wave, find your landmark first and go back where you were. If that doesn't work, it means the wave has shifted positions (not unusual, especially as you climb higher). Start immediately to explore the area for better wave. If out of wave, your decent rate will usually be high, so kick the speed up to maximum maneuvering speed and try to reestablish wave contact. The higher you go the less will be the rate of climb, and you need to gently explore the surrounding area for the best lift. I suggest not doing any 360-degree turns. You may quickly find yourself miles from your original turnpoint.
There may or may not be lenticular clouds, and if there are, they may quickly form and dissipate or they may move. Once a wave cloud forms right over Mount Washington, it will usually start to grow and may expand quickly to the point of covering the area. At eye level to the mountain top it looks almost like a magical waterfall with cloud streamers being forced down the slope into the very strong down wash of the lee side.
You always need to watch the cloud cover below you. It always impresses me on how quickly an area can over develop to the point of having solid cloud cover. If holes are getting few and far between, GET DOWN NOW. Cloud holes can close up with great rapidity. I once was watching a hole 1,000 feet below me as my escape route when I started a slow downward spiral. I was through my first turn when I looked down and the hole was gone. Do not risk getting caught on top.
If you are caught on top, spinning through cloud cover not knowing where the mountains are can be extremely unhealthy. The Nimbus is not rated for spins, so this has never been an option for me. GPS technology is excellent for locating a valley airport below a cloud cover. If the cloud cover is thick and you must descend through it, you are at great risk for becoming disoriented. Few of us are instrumented rated or have artificial horizon instrumentation. The concentration required in descending through clouds is very difficult to maintain for long periods. Across the pond where cloud flying is legal, Derek Piggot insists his pilots are competent to fly on the turn and slip indicator before they graduate to an artificial horizon. One must also keep his compass bearing and yaw string straight. If caught on top, I suppose you could try radioing for the tow plane or another power plane to come help guide you down, assuming he could find you. It is a very big sky! The safest and surest method to avoid these problems is to descend before you get in trouble.
Aircraft icing, snow, and freezing rain is always an issue in mountain wave and ridge flying. There are temperature variations and moisture variations, and conditions can be in a continual state of flux. You need to especially watch for wing icing when under any clouds. If your wings start to ice up, get out in the sunlight fast and remember your L/D has just dropped dramatically. If your controls begin to ice, you will usually ``feel it'' in the stick and rudder pedals. While you are racing for the sun, keep working the controls including the dive brakes to prevent complete freeze up. Do not try to land if you are having control problems. If possible, hang around in the sun for awhile and it will melt.
Rain is no fun to fly in as you can't see diddley squat, but at least you can see the ground. In snow you may not even be able to see the ground. Continue VFR flight into instrument meteorological conditions (IMC) and you are a prime candidate for loss of control caused by disorientation or controlled flight into terrain. Avoid or get out of both. If caught in snow, your visibility may be only yards. Keep the yaw string straight, fly towards the field on a compass bearing, keep slip and skid ball centered, and you may eventually fly out of the flurry or at least to somewhere where the visibility is better.
Once on top, relax and look around at the magnificent view. Hopefully, you brought a camera to take a few pictures including one of your altimeter. After all, it isn't every day a glider pilot gets to see his altimeter spun around a couple of times! If you take a snapshot of yourself, I will wager the photo will have someone with a large smile on his face. We have all flown airliners and looked down from 20,000 feet, but it is entirely different to know that you were the pilot of a motorless aircraft that reached such heights. Also, let us not forget the cherished gold or diamond altitude leg for which you have worked so hard. If you climb over 25,000 feet you are eligible for the Symons Award and your first Lennie Pin.
You now have been at altitude for an hour, maybe five or six hours. The air has been smooth and relaxing. You begin to think this wave thing is a piece of cake. Your brain might be a little groggy from being on oxygen, and the world looks like a peaceful place from your high-altitude dreamland. It is time to splash a little water on your face and prepare for the reality far down below.
Before starting your descent, empty your bladder, take a drink, secure any lose gear, firmly tighten your straps, and start your descent at your pleasure. Another safety factor to keep in mind is the sun setting on the airfield. When you are at altitude it may look like three in the afternoon on a bright day. If flying late in the day, do not forget to check your watch and look at the ground every now and then. The mountains will cast shadows before official sunset, and by the time you get down it could be getting very dark at the airfield.
On your descent and in the pattern always be prepared for turbulence, wind shear, and cross-shifting winds everywhere or anywhere. Watch your flying speed and never exceed your ships maximum maneuvering speed. This is what maximum maneuvering speed is intended for, namely the maximum speed in turbulence so as not to exceed design load limitations.
Give yourself sufficient altitude for a few passes over the airport to get a feel for the lower level wind conditions. This is also a good time to look at the field and ``mentally'' set up your pattern. Do your pre-landing checklist well before entering the pattern. Once you are ready to enter your downwind, announce your intentions to the area traffic. Do not be afraid to carry extra or a lot of added speed depending on the level of turbulence. You want full and responsive control throughout your pattern. Mountain wind shear is not uncommon.
Congratulations! You have made your first wave flight. Secure your glider. Get most of your badge documentation completed with the appropriate signatures. Now, it is time to relax, relive your flight with others over a good meal, and possibly even have a Barley Pop or two! You have put in an extensive amount of time, preparation, effort, and probably a buck or two in achieving this experience and soaring goal. You are one of a select few who have been that high, seen that view, and mastered the elements of mountain wave flying. That night you will have your best night's sleep. You will also bask in the memory for years to come and may even get hooked on this ``mountain flying thing.''
Mountain wave and ridge flying can be and are as safe as other aspects of the total soaring experience. The thermal-only pilot upon his first reading might say ``Gee, this stuff sounds pretty wild and dangerous.'' It is not, if done properly, and that is the reason for this introductory article, besides trying to get you interested and enthusiastic about learning more. Ask yourself what your reaction was the first time you learned about cross-country perils when you were a student. I suspect it sounded pretty ``wild and dangerous,'' too. They say a good pilot is always learning and that is certainly true. If you are ready and looking to learn something new, here is a great opportunity.
P.S. The young lady hasn't got my job yet, but she in now working on her masters degree and I am keeping a close watch over my shoulder!
From the October 1997 issue of Flying magazine, the most gruffly macho of all flying magazines: ``Now, this is a glider. Stemme USA reports that its latest design, the S10-VT, is nearing certification by both the FAA and European authorities (the company expected certification to be a done deal by mid-August). The S10-VT -- an upgrade of the company's S10-V powered sailplane -- is a two-place side-by-side retractable-gear high-performance sailplane powered by a front-mounted engine swinging a retractable propeller. The propeller is a neat concept: When the starter is engaged, centrifugal force extends the blades and keeps them extended as long as the engine is turning; when it's time to soar, just turn off the Rotax, fold the blades and stow them behind the retractable front cowling. Another improvement on the model is the powerplant, a turbocharged Rotax 914 four-stroke engine that puts out 115 horsepower up to 12,000 feet, which greatly facilitates operations from higher elevations. Max cruise speed, says Stemme, is 127 knots, and max range exceeds 840 nautical miles. However, if you do run out of fuel at 12,000 feet, with a lift-to-drag ration of 50:1, you'd better find an airport within the next 100 miles or so, and that's if there's not much lift that day.''
From the December 1997 issue of AOPA Pilot: ``Europa Aviation Ltd., located in North Yorkshire, England, has designed a set of glider wings that are interchangeable with the kitplane's regular wings. The company promises two airplanes for the price of one. The glider wings are not in production, and no price has been established. The Europa, as the aircraft is known, can be completed in 700 hours and costs about $40,000, including the $24,000 airframe kit, a Rotax 914 engine (recommended), instruments, paint, and interior. It is available as a tri-gear model, or with a single wheel under the fuselage. Tests are in progress at Lakeland, Florida, on a Europa powered by a Continental O-200 engine. See the web site www.europa-aviation.co.uk or call Europa Aviation in Lakeland at (941) 647-5355.''
Figure 2: The Europa.
(AOPA Pilot)
This is a condensed version of an article titled ``On a wing and a vortex'' by Martin Brookes in the October 11, 1997 issue of New Scientist, sent to me by my father, Morrie Tuttle. --Editor
``About five years ago, insects couldn't fly -- not according to the conventional laws of aerodynamics,'' says Charles Ellington, a zoologist from the University of Cambridge. Analyses of insects in flight could find only about one-half to one-third of the lift needed to support their weight. Similar calculations showed that small birds and bats also conjured up mysterious and unknown sources of lift.
The problem is this. Conventional aerodynamics -- used in the design of aircraft and helicopters -- rely on ``steady-state'' situations such as a fixed wing moving at a constant speed or a propeller rotating at a constant rate. By contrast, the motion of insect wings is a complicated 3D affair. Nevertheless, until recently researchers were not convinced that this special motion could generate any unusual sources of lift. For years, they struggled to explain insect flight using a theory rooted in steady-state situations, not understanding why their aerodynamic sums didn't add up. Ellington summarizes it neatly. ``Since the 1950s, we've been looking at insect flight with the wrong picture in mind.''
This picture left out some obvious differences between insects and aircraft. For a start, insects are small. On this smaller scale, the viscosity of air becomes more important so that, for the average insect, flying through air is like swimming through treacle [molasses]. Because of this, the classic airfoil shape that generates an aircraft's lift does not work, and insects have evolved entirely different forms of wing.
For medium to large sized insects such as butterflies and dragonflies which have wingspans of between five and ten centimeters, thin plate-like wings with a slight camber produce the most lift, but even thin, membranous wings are too cumbersome for smaller insects to drag around, and nature has had to think again. The tiny thrips, an insect with a wingspan of only a millimeter or two, cruises the aerial highways on wings which are little more than hairy stalks. And does it extremely well.
So how can these strangely shaped wings create lift? For conventional aircraft, the wing's camber and its angle of attack create the necessary low pressure air over the upper surface. But the lift force created in this way just isn't enough to keep an insect in the air. ``Somehow, insects produce two to three times more lift than you'd expect,'' says Ellington. The only way to explain insect flight would be to find another way of producing low pressure on top of the wings to augment the lift generated by conventional mechanisms.
The way paper airplanes fly offers some clues. Just before a paper plane comes to rest, when the tail begins to drop and the nose sits high, it gains an extra bit of lift before swinging lazily back to the ground. This phenomenon is known as delayed stall and occurs when sharp-edged wings cut through the air at high angles of attack.
To understand what is going on, imagine the air striking the leading edge. At low angles of attack, the air flows smoothly over the surface creating the pressure difference that leads to lift. But at high angles, the flow breaks away from the surface and begins to turn somersaults, forming a vortex. This vortex sticks to the upper front portion of the wing, and the swirling, fast-moving air creates a low pressure area that generates lift. It is this leading edge vortex (LEV) that gives a paper plane its final boost before it lands.
But delayed stall does not keep the plane airborne for long because the effect is only momentary. The rotating air cannot spiral in on itself forever, so the LEV very quickly becomes unstable and tumbles away from the wing's surface.
Nevertheless, Ellington and his team recognized that these kinds of aerodynamic effects could plan an important part in insect flight. The next step was to work out how they were created during the complex beating of an insect wing.
Monitoring and interpreting the 3D airflow across small flapping wings is not easy. As well as seeing the motion of the airflow, researchers also have to measure its speed and direction. To start with, Ellington's team chose to work on the hawkmoth because of its large, 10-centimeter wingspan, and because its wing motion is typical of many other insects. The hawkmoth beats its wings 26 times a second, and by tethering the moth in a wind tunnel, they monitored the path of horizontal smoke trails flowing over the insect's flapping wings.
``When we got the flow visualization results from the hawkmoth, we didn't know what to make of it,'' says Ellington. As expected, his team could see a vortex forming along the leading edge of the wing, but rather than tumbling off the back of the wing, the vortex clung to the surface while the air within it seems to spiral out towards the wing tip with a whirlwind.
Exactly what caused the spiral flow they couldn't say. ``What we needed was a bigger insect so that we could see what was going on in more detail,'' says Ellington. One of the peculiar predictions of aerodynamic theories is that it is possible to mimic fast flow over a small object by generating a slow moving airflow over a large object. All Ellington and his team had to do was build a model of the hawkmoth ten times larger than life.
In wind tunnel tests with smoke trails flowing over this flapping model, the head-on view of the model shows the wings raised, with their tips pointing almost vertically upwards. As the down stroke begins, small plumes of smoke emerge from within the body of the wings at points along its leading edge. The smoke detaches from the wing and begins to somersault into a spiral. Clearly, a leading edge vortex has formed.
Then something astonishing happens. During the down stroke, the center of the spiraling smoke is pulled out along the leading edge of the wing like a party streamer. This enables the whole vortex to stay stuck like a limpet [a marine mollusk that has a tent-shaped shell and adheres to rocks of tidal areas] to the wing surface until well beyond the halfway point in the down stroke.
This was just the evidence Ellington and his team had hoped for. With the vortex stuck to the surface of the wing, they now had another lift-producing mechanism. ``Our observation is a confirmation of what we knew had to be there,'' says Ellington. At low air speeds, the vortex is extremely small and it takes something as large as the hawkmoth model to see it properly. ``That's one of the reasons why it wasn't spotted in earlier experiments,'' he says.
Ellington calculated how much of an effect this might have. The results were conclusive. The lift force generated during the down stroke was about one and a half times that needed to lift the weight of the hawkmoth -- more than enough to keep it aloft.
``We've observed a new aerodynamic phenomenon, but we don't know how it's produced,'' says Ellington. Nobody knows how the helical flow of air is maintained across the wingspan. One possibility is that because the tip of a flapping wing moves faster than its base, an area of relatively low pressure air at the tip might suck the vortex along the wing. But other observations show that air moves in the opposite direction beneath the wing. Further work is needed, says Ellington, and there are many other mysteries that remain unsolved. Ellington and others have detected signs of other vortices generated during each beat but have yet to measure them accurately enough to gauge their effects. And while most research has focused on large insects, there is no guarantee that the same high-lift mechanisms are at work in much smaller insects such as the thrips. Then there is the question of the number of wings. Many insects have four of them, but just why this might be better than two is still a mystery.
For the moment, though, Ellington his colleagues are pleased with their progress. ``We are teaching the aerodynamicists something new. And that's a nice feeling,'' says Ellington.
In the November 7 issue of Nature, a team of researchers explains why hovering is something most birds don't like to do -- or can't do -- for very long. Kenneth P. Dial of the University of Montana and colleagues surgically implanted strain gauges in the wings of three black-billed magpies. The devices measured the force exerted by the main flapping muscle with each beat. The birds then flew in a wind tunnel at a range of speeds.
The strain gauge allowed the scientists to calculate the power required to maintain a given speed. (Power is the amount of work done per unit of time.) Hovering took nearly twice as much power as flying at average speed, the researchers found. Even when the magpies flew at top speed, they expended far less power than they did when they hovered. Evidence suggested that when they hovered, the birds were working at their physical limits. Their wing muscles appeared to be employing anaerobic metabolism, a source of energy that can't be sustained for long.
There are clearly exceptions to this. Hummingbirds, the authors said, have an unusual shoulder design that allows them to generate lift on both down-beat and up-beat. But birds with a body design similar to magpies are likely to have strict limits on their abilities to hover.
After seeing the picture of Bill Brine in the last newsletter, T. Guy Spencer wrote to say, ``I got a special chuckle from seeing `the biggest little Boy Scout in Massachusetts.' You see, many years ago, when I was a Scout master in Weston, one of my scouts was...yes... Bill Brine. No kidding.''
In a story that swept the Internet (eg, www.avweb.com), a pilot was forced to land an Aeronca Champ in a field near Dayton, Ohio, due to an unnamed problem. The pilot was hand-cranking the engine after making repairs (no starter), when it back-fired as it started, blowing the throttle open. The plane accelerated across the field and took off on its own, climbing to 12,000 feet before eventually ``landing'' in a bean field approximately 90 miles away, badly damaged, but mostly intact.
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For more information about MITSA, you can contact the club by email, visit our web page, or contact Joe Kwasnik, our director of membership listed above.
The Leading Edge is the newsletter of the MIT Soaring Association, Inc. The newsletter is edited by Mark Tuttle, and published every other month (more frequently during the soaring season). The submission deadline is the first of each month. Please send any inquiries or material for publication to Mark Tuttle, 8 Melanie Lane, Arlington, MA 02174; tuttle@crl.dec.com
The Leading Edge
The newsletter of the MIT Soaring Association
December 1997
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