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Ground School: Seaplanes: Taxi & Takeoff, or “Get your floaties on”

Ground School: Seaplanes: Taxi & Takeoff, or “Get your floaties on”

Seaplanes and X-Plane 
Originally by Chuck Bodeen with edits for XP11 by yours truely ūüėČ

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PECULIARITIES OF SEAPLANES
Once a seaplane is in the water and released from contact with a dock it is subject to weathervaning which is the tendency of the plane to face the wind. Its the same physical principle that keeps an arrow going straight ahead. The strength of this effect depends upon how much of the plane is behind the center of buoyancy.

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WEATHERVANING

Wheeled airplanes tend to pivot on the main landing gear wheels. Tail wheel planes have more side area exposed to the wind behind the main gear and are more subject to weathervaning than planes with tricycle gear. For seaplanes, the pivot is around the center of buoyancy which varies according to the pitch attitude in the water. At rest in the water a seaplane acts like a tail dragger. As it starts to move forward you must hold the yoke full back to counter the moment produced by the engine thrust. This raises the nose of the floats and there may be just as much wind-exposed side area ahead as there is behind producing virtually no weathervane effect. If this progresses into a deep plow the weathervaning can even be reversed! Finally, when the floats are moving fast enough to plane or up on-the-step, the effect of side winds can be almost the same as a taildragger again. Because of weathervaning there are only two practical taxiing speeds: slow and on-step although plowing is sometimes useful in turning.

DHC-3 Otter_FLOAT_17

Getting on the step requires the nose to be lowered and staying there is no easy task. You must use just the right amount of back pressure on the stick. Too much or too little will increase the drag and reduce speed. For taxiing, the throttle has to be reduced after you are on the step. Continuing on step with full power you will eventually reach the speed where the plane will lift itself off the water and then fly like a regular airplane. Lack of proper elevator control on a step taxi or takeoff run can result in porpoising which is a pitch oscillating condition that can increase in magnitude if you do not reduce elevator back pressure. Otherwise you may need to reduce power and abort the takeoff.

You may think that smooth water would be the best. Actually the rough water associated with a nice headwind allows you to takeoff at a lower waterspeed which reduces the drag on the floats. The fact that you are cutting along across the tops of the waves also reduces water drag. Depending upon the design of the floats, it is usually not recommended that you rotate as the plane lifts off the water.

Landing is made difficult by lack of visual contact with features on the ground and is particularly troublesome when coming in on glassy, smooth water. On the other hand, hitting rough waves at high speed can damage the floats, so you should always use the slowest possible water speed. Usually the waves will be caused by the wind, so even without a windsock you should be able to determine the proper heading for final approach. Never land parallel to the wave fronts rocking the boat is not a good idea.
So after landing what do you do? Once again you are at the mercy of the wind and with no ground-gear friction or brakes to help you steer. Sailing is a technique that allows you to take advantage of weathervaning and get where you want to dock, even by going backward in the water! After landing in a wind of, say, 20 knots you can set the engine to idle, and use the flight controls to turn the nose toward the dock. Go past the dock and then use power and control to finish.

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SAILING

Docking can be rather tricky because in a real plane you will be out of the cockpit standing on one of the floats. With the engine off, you may need a paddle (standard equipment on seaplanes) if you need just a bit more propulsion, or you might have to use your foot to keep the floats from hitting the dock too hard. There is a lot more to learn including the combined effects of currents and wind.

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TAKEOFF

Here is how the takeoff goes. Once in the water, water rudders are lowered (more about that later) and gear is raised followed by a slow taxi out to the end of the takeoff area and a turn into the correct heading. At this point be sure the brakes are off. In the water, the brakes activate an anchor that will tie you to the spot you drop it. Now raise the water rudders, lower the flaps one notch, set the elevator trim for takeoff, and advance to full pitch and throttle. Pull back on the yoke to reduce drag by raising the leading edge of the pontoons. At about 40 knots, push the yoke forward to get the tail of the pontoons out of the water and have the ship plane on-the-step. At 60 knots the plane will lift off the water by itself. Come to think of it, this is quite a bit like a takeoff for a tail dragger, X-Plane has a default wave height which causes the ripples in the altitude, but I made the takeoff tests with little wind and wave height set to 0.3

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TAKEOFF FROM THE WATER HAS FOUR CRITICAL STAGES

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START TAXI, UP ELEVATOR FOR PLOWING, DOWN ELEVATOR FOR ON-THE-STEP, AND THEN LIFT OFF

MODELING WATER RUDDERS
Real water rudders are usually placed at the rear of the pontoons or hull and are retractable so as not to be damaged or cause excessive drag during high speed operation. X-Plane has only one way to handle a water rudder. On the landing gear page, you can specify the longitudinal position, the area of the rudder, and the maximum angular movement. You have no control over the vertical position and X-Plane assumes that the water rudder is completely submerged if any part of the fuselage or floats is in the water.

LANDING HELP COMING SOON.

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Still having trouble? Duct Tape can help! no seriously check this out:

https://forums.x-plane.org/index.php?/files/file/20632-duct-tape-10/

VATSIM Event PAJN – PAWG VFR Helper

VATSIM Event PAJN – PAWG VFR Helper

This flight is fairly straightforward, starting out in Juneau,

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out the Gastineau Channel,

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Flying south along Stephens Passage

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into Frederick Sound,

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Humpback whales bubble net feeding in the waters off Pinta Point, Frederick Sound, Inside Passage, Southeast Alaska

Humpback whales bubble net feeding in the waters off Pinta Point, Frederick Sound, Inside Passage, Southeast Alaska

then turning southeast past Farragut Bay,

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then flying south past Petersburg,

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then following Mitkof Island

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to Wrangell.

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Ground School: Decoding METARs

Ground School: Decoding METARs

The most important factor in determining which runway to use for takeoff or landing is arguably the weather. Whether you are on VATSIM, PE or offline (pun intended) you cab obtain current and forecasted weather reports with a METAR. This Class will help you decode a METAR and teach you what the abbreviations stand for.

Requesting a METAR

VATSIM

To request a text METAR on VATSIM using XSB, type this in the chat:
.metar CODE where CODE is the ICAO of the airport wanted.
i.e. Juneau, you would type .metar PAJN

X-PLANE

To request a METAR click your map on the airport desired to obtain the radio frequency needed to hear the ATIS and get the latest report.

A Typical Example

Lets examine a METAR for, say, Amsterdam, sexy women and good food! METARs right, sorry!

Keep in mind over in Europe they use meters instead of miles.

EHAM 291050Z 24015KT 9000 RA SCT025 BKN040 10/09 Q1010 NOSIG

Decoded: METAR for Amsterdam Schiphol dated the 29th at 10h50z; wind direction is at 240 degrees and 15 knots; 9000 meters visibility; Rain, scattered cloud at 2500 feet; broken cloud at 4000 feet; Temperature is 10 degrees; dew point is 9 degrees; QNH is 1010; No significant change expected in the next few hours.

Decoding Legend

In the example above you get a vague idea of what some parts of a METAR mean, let’s break it down by sections and help you understand further.

EHAM 291050Z 24015KT 9000 RA SCT025 BKN040 10/09 Q1010 NOSIG

The first section always contains the ICAO code for the airport

EHAM 291050Z 24015KT 9000 RA SCT025 BKN040 10/09 Q1010 NOSIG

The second part is the date

EHAM 291050Z 24015KT 9000 RA SCT025 BKN040 10/09 Q1010 NOSIG

After the date is the time of the report, which is always UTC

EHAM 291050Z 24015KT 9000 RA SCT025 BKN040 10/09 Q1010 NOSIG

Then the wind direction in degrees and its speed in knots

EHAM 291050Z 24015KT 9000 RA SCT025 BKN040 10/09 Q1010 NOSIG

Visibility in meters (for Europe, miles are used elsewhere)

EHAM 291050Z 24015KT 9000 RA SCT025 BKN040 10/09 Q1010 NOSIG

RA means there is rain

EHAM 291050Z 24015KT 9000 RA SCT025 BKN040 10/09 Q1010 NOSIG

SCT means there are scattered clouds

025 means they are at 2500 feet

EHAM 291050Z 24015KT 9000 RA SCT025 BKN040 10/09 Q1010 NOSIG

BKN means there are broken clouds

040 means they are at 4000 feet

EHAM 291050Z 24015KT 9000 RA SCT025 BKN040 10/09 Q1010 NOSIG

In this section the temperature is always first, followed by the dew point so:

  • The temperature is 10 degrees
  • The dew point is 9 degrees

EHAM 291050Z 24015KT 9000 RA SCT025 BKN040 10/09 Q1010 NOSIG

When you see NOSIG at the end of a METAR this means that no significant changes are expected in the next few hours

Decoders

There are some free tools online which allow you to decode METARs easily and I recommend their use to learn what all the abbreviations and terms within them mean.
http://heras-gilsanz.com/manuel/METAR-Decoder.html
http://www.iflightplanner.com/Resources/MetarTafTranslator.aspx
http://www.metarreader.com/

 

Lake Hood, Anchorage hot spot for floatplanes, will get three new hangars

Lake Hood, Anchorage hot spot for floatplanes, will get three new hangars

from ADN.

   A $15 million project underway to build new hangars at the Lake Hood Seaplane Base in Anchorage aims to alleviate the pent-up demand for housing smaller aircraft there.

A company called Lake Hood Hangars broke ground earlier this year on the first of three hangars. The other two are set to be built next year.

Steve Zelener, company owner, said there’s huge demand for more hangar space in Alaska’s largest city. Proximity to the lake itself also comes at a premium, and the new hangars will have nearby access to the¬†water.

The project also involves doubling the number of floatplane slips Zelener owns on Lake Hood from nine to 18.

Lake Hood Hangars developer Steve Zelener, center, confers with Remote Alaska Solutions construction company president Seth Kroenke, left, broker and project manager Stormy Jarvis, near right, and construction manager Igor Sapelnik, right, during a visit to the construction site of their first building on Tuesday.  (Erik Hill / Alaska Dispatch News)

Lake Hood Hangars developer Steve Zelener, center, confers with Remote Alaska Solutions construction company president Seth Kroenke, left, broker and project manager Stormy Jarvis, near right, and construction manager Igor Sapelnik, right, during a visit to the construction site of their first building on Tuesday.  (Erik Hill / Alaska Dispatch News)

The hangars, located on Aircraft Drive near a taxiway, will be about 24,000 square feet each. Taking up a bit more than 3 acres, the first massive building is still under construction, rising about 28 feet high and still without doors.

The rest of the land where the next two buildings will be located is still just dirt.

The hangar space will be both leased and sold, running from about $845,000 to $985,000 to buy and starting at about $1.35 per square foot per month to rent.

There were¬†nearly 8,000 registered aircraft in Alaska and around 3,300 of those were¬†registered in Anchorage as of the end of July, said Stormy Jarvis, manager of the hangar project. Most of those in Anchorage are small planes, she said, and that’s likely the case for the whole state.

“We see a need, and there’s also this waiting list for float slips at the lake,” she said. “There’s a hangar shortage. That’s a resounding message.”

One of six units in the first hangar building currently under construction faces the terminal at Ted Stevens Anchorage International Airport on Tuesday. (Erik Hill / Alaska Dispatch News)

One of six units in the first hangar building currently under construction faces the terminal at Ted Stevens Anchorage International Airport on Tuesday. (Erik Hill / Alaska Dispatch News)

Tim Coons, manager at the Lake Hood base, said the waitlist for slips is about 10-11 years old. The base, part of Ted Stevens Anchorage International Airport, has long claimed to be the busiest seaplane base in the world, he said. About 750 people at any given time have permits to park their planes there, he said.
“Most of the area around the lake has already been developed. This was one area that was still open,” Coons said. “Alaska has always presented a harsh environment. Just like anybody who would like to have the ability to keep a nice asset inside, airplane owners are no different.”
Even smaller planes can cost anywhere from $50,000 for something used, to a few million dollars for something new, said Zelener. Snow, cold and ice, as well as vandalism and other damage, are some of the reasons people want to keep their aircraft indoors.
“Outside elements are going to contribute to wear and tear of an aircraft before it has to be rebuilt,” said Seth Kroenke, president of Remote Alaska Solutions, the contractor on the project.
Integrated concrete form technology is being used for the Lake Hood Hangars buildings. The ICF blocks snap together and are then reinforced with horizontal and vertical steel bars before concrete is poured into the eight-inch gap. The technique provides strong, insulated walls with fire protection while also creating a strong sound barrier between units, said developer Steve Zelener. (Erik Hill / Alaska Dispatch News)

Integrated concrete form technology is being used for the Lake Hood Hangars buildings. The ICF blocks snap together and are then reinforced with horizontal and vertical steel bars before concrete is poured into the eight-inch gap. The technique provides strong, insulated walls with fire protection while also creating a strong sound barrier between units, said developer Steve Zelener. (Erik Hill / Alaska Dispatch News)

The hangars are designed with energy efficiency in mind, he said, and they use concrete insulated with foam to handle wide-ranging fluctuations in temperature.
The project has been an idea since 2010, Zelener said. He’s also the owner of Zelener Group, which has commercial real estate in Anchorage, Nome and Dutch Harbor.