Aerial Pursuits - Trike Glossary

Glossary of Trike Terms

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Terms

A-Frame	See "Control Bar"
Base (Trike Base)	The trike part of the trike. Sometimes referred to in a twee way as the "Chariot", a term disliked by the author.
Base Tube (trike)	The tube running horizontally under the pilot
Base Tube (wing)	The horizontal tube at the bottom of the Control Bar.
Battens	Aerofoil-shaped aluminium tubes designed to force the surface of the sail int the required aerofoil shape. They fit down "batten pockets" sewn into the sail, and are usually under some tension, using either elastics or sp rings.
Chariot	See Base (Trike Base) ... yechhh.
Control Bar	The triangular frame below the wing which is used to control the wing, and acts as the bracing for the wing under positive loads. Also known as the "A" frame
Dive Sticks	Rods mounted on the ends of the leading edges which restrict the minimum angle of attack of the tips. They play no part in normal flight and are an aid to dive recovery. Also known as "tip deflectors"
Down Tubes	The two vertical members of the wing Control Bar. Also known as Uprights.
Drag Links	These are the narrow tubes that may connect from the axle where the wheel is attached, to somewhere under the seat frame onto the trike unit base tube. They provide fore/aft bracing for the gear strut
Fin	An optional vertical stabiliser usually mounted on the rear of the keel to provide additional directional stability at high speed. It may take the form of cloth covering the triangle formed by the kingpost, keel and rear upper rigging wire (Raven, Skylink, etc..), or a keel pocket with or without a rigid extension.
Flying Wires	The cables bracing the Control Bar Fore and Aft on the wing.
Flex Wing	A wing loosely based on the original Rogallo frame with a trailing edge supported only by sail tension. Usually controlled (with some exceptions) entirely by weight shift.
Front Strut	A tube bracing the nose of the trike to the top of the mast. Takes a small percentage of air loads and stops the mast from bending on landing. Also known as "Compression Strut".
Instruments	Altimeter: Measures the height of the aircraft by measuring the barometric pressure. Required by law in Australia. Tachometer: Measures the operating speed of the engine. Not mandatory, but highly recommended, as it will help you assure that the engine is capable of sustaining full revs/power. ASI Air Speed Indicator: Measures the speed the aircraft is travelling relative to the surrounding air (not the ground speed) using a venturi system. Highly recommended. VSI Vertical Speed Indicator: (or Variometer) measures the rate of clime or ascent by determining the rate of change of barometric pressure. Not generally necessary. Compass The Magnetic compass is used to determine the direction the aircraft is pointing (the heading). As it uses the Earths magnetic field, it is subject to variation (magnetic North varies in relation to True North by different amounts around the world) and Deviation, which is caused by the influence of nearby metallic objects. A good compass will have both adjustments to cancel out severe deviation as well as a card showing the amount of error at each compass point when the compass was "swung" or tested. Magnetic Compasses are also subject to errors of lag and overshoot during turns. CHT Cylinder Head Temperature: Measures the temperature of the cyliner heads and is a good guide to the state of lubrication of the engine. Relatively slow response. Recommended. EGT Exhaust Gas Temperature: Measures the temperature of the exhaust gasses. Provides quick feedback on the health of the combustion process. A very high EGT usually indicates too lean a fuel mixture, with attendant danger of meltdown/siezure in the combustion chamber. Very Highly Recommended Hour Meter keeps track of the number of hours an engine has had in service. Mandatory in some aircraft by law.
Keel	The tube running fore and aft on the wing.
Keel Pocket	A deep pocket joining the rear of the keel to the sail proper on earlier wing designs to aid handling.
Kingpost	The vertical tube above the wing to provide support for negative air and ground loads.
Leading Edges	The two wing tubes providing the "leading edge" of the wing. These are in bending mode in flight and are designed to flex. This aids in handling.
Luff Lines	See Reflex Bridle
Mast	Usually the vertical member of the trike
Nosewheel Brake	Many trikes have a drum brake on the front wheel, activated by a lever on the left hand foot peg. Simpler units may opt for a pad which applies friction to the wheel itself (not good in the wet!). Less common, but on more expensive trikes, rear-wheel or 3-wheel brakes are used.
Pod	A (usually fibreglass) fairing at the front of the trike to keep the wind off the pilots feet & lower body.
Pullback cables/strap	The cable or strap from the spreader junction to the rear of the keel that holds the spreaders back.
Reflex Bridle	Wires or lines from the top of the kingpost to the rear of the inner battens. Designed to create an up-elevator effect at low angles of attack. On some trikes these can be tightened in flight to provide in-flight tr im.
Rollover	If trike nosewheel steering is messed up on landing, the result is usually the trike doing a nose-flip and rolling over on one leading edge, resulting in a broken leading edge, prop, keel, mast and universal at the very least.
Side wires	The cables joining the lower corners of the Control Bar to the outer Spreaders of the Wing (usually two per side). They provide the primary bracing for positive flight loads.
Skirt	A fabric cover which fills in the area on the sides of the trike between pod and the rear of the unit.
Spats	Fairings for wheels, usually fibreglass.
Spreaders	The transverse spars in the wing. Usually quite thick, they are in compression in flight. Also known as "Cross Tubes"
Steering Damper	A dashpot which stops nosewheel shimmy. Helps prevent rollovers!
Swing-through	Trikes usually swing forward to a more nose-up position in flight compared with the ground. This is marked on takeoff under full thrust and can be disconcerting for new pilots.
Throttle	A foot throttle for the engine is usually mounted on the right-hand foot-peg. A secondary cruise hand throttle may be mounted on the seat frame.
Topless Wing	A wing lacking upper rigging wires and a kingpost. This is usually acheived using a cantilever crossbar (often composite), or substituting struts for lower side wires.
Trapeze	See "control Bar" or "A-Frame"
Universal joint	A joint connecting the wing keel to the trike mast, allowing motion of the trike in both roll and pitch. Usually does not allow yaw, since this could allow the propeller to contact the rear flying wires or side wi res. Also known as "Hang Point Channel", depending on design.
Upper Rigging	The cables on the upper wing providing support for negative loads, in conjunction with the Kingpost.
Uprights	See DownTubes.
Variable Geometry (VG)	Also known as Variable Billow (VB). A mechanism for widening the nose angle of the wing, thus producing more spanwise sail tension and less twist, usually, but not always by decreasing the rake of the speader bars. (Another method uses cams on the end of the spreaders). Used to improve speed and glide, usually at the expense of handling.