Subsections

• 14.1 Making support tubes / sheaths
  • 14.1.1 Introduction
  • 14.1.2 Requirements
  • 14.1.3 Procedure
  
  
• 14.2 Common product names
• 14.3 Commonly used Terms and Acronyms
• 14.4 Conversions
  • 14.4.1 Lengths and sizes
  • 14.4.2 Weights
  
  
• 14.5 Further information

14. Appendix

14.1 Making support tubes / sheaths

14.1.1 Introduction

When routing the control wires of for the elevator and rudder on the QFII, they need to be secured in such a way that when the wire is under compression it doesn't buckle out, causing a loss of control. For wire diameters of 0.6mm or less it can often be difficult to locate suitable tubing for reinforcement so the natural solution is to make our own.

14.1.2 Requirements

10cm length of wire of one size larger than you plan to use for your control wires (ie, 0.8mm for 0.6mm controls)

Very thin paper (cigarette wrapping papers are excellent for this)

Gum glue or PVA

Clean wood or cork block

14.1.3 Procedure

• Take a piece of paper of about 70 x 30mm, fold along the long edge to create a 5mm fold over
• Place wire into the corner of the fold
• Hold down fold and start rolling the wire forward, this should make the paper start rolling up
• When there is only about 5mm left of paper to roll up, apply a small quantity of gum or PVA
• Finish rolling paper up
• Place wood/cork block over the tube (with wire still inside) and roll forward several times, this compacts the tube and ensures that there are no loose edges
• Gently remove the tube from the wire
• Set tube aside for drying

14.2 Common product names

• METHYLATED SPIRITS, also known as denatured alcohol or metho. Methylated spirits is a mixture of ethyl alcohol (95%) and methyl alcohol (%5). The methyl alcohol is poisonous and is added to prevent the methylated spirits being used as cheap drinking alcohol. We use metho as a thinning agent for epoxy.
• CYANOCYLOCRATE, also known as CA, SuperGlue and CrazyGlue.
• CARBON FIBER TOW, also known as lose ribbon or strand. CF Tow usually consists of several thousand raw CF strands wrapped together in a ribbon/tow, from this product most CF products are made, such as booms, cloth and even propellers.
• LAMINATING FILM, also known as Doculam. Laminating film of 1500 microns thickness is commonly used for covering small planes. The film is typically supplied on rolls in 300~400mm widths with a length of 100~200m. The film has two distinct sides, a smooth outer surface and a matt, slightly rough inner surface which is covered with the adhesive material. Off the roll laminating film has a slightly opaque appearance. When heated the adhesive material converts and becomes translucent. Laminating film is very tough for its thickness and can handle a lot of heat without suffering burn-through.
• POLYURETHANE/ACRYLIC VARNISH, also referred to as ``Minwax Polycrylic'' to a lot of modellers. This paint is used as a replacement for resin when fiber glassing. While it does not possess the strength or rigidity of resin it is a suitable replacement for areas such as covering surfaces for the sake of impact resistance and surface durability. Each paint brand will have their own particular product namings, the key is to look for ``water wash-up'', ``polyurethane'' or ``acrylic'' stains and varnishes. In Australia/NewZealand a common one is Cabots Crystal Clear.

14.3 Commonly used Terms and Acronyms

AUW

All Up Weight; commonly used to describe the total weight of a plane in flying condition, ie complete with radio gear, batteries and anything else required to fly

CF

Carbon Fiber; A very popular material used for its extremely high tensile strength. CF is not good however for shock or compression loads.

CG

Center of Gravity (CoG); commonly refers to the longitudinal (pitching) static mass balance point of the aircraft. Typically the CG is determined by balancing the plane on two points located along the wing surface. A plane is considered to be ``nose heavy'' if the aircraft pitches its nose downwards at a given balance point or ``tail heavy'' if the tail of the aircraft pitches down. There is also a latitudinal static balance point, typically indicating which wing is heavier.

FG

Fiberglass; made of thousands of strands of very fine glass fiberglass is an extremely versatile material which only recently has been supplanted in some areas by carbon fiber cloth.

L/D

Lift Drag ratio; The L/D is a term commonly used with gliders when talking about the ``optimal L/D'' ratio. There are two points of particular interest with L/D, at the optimal ratio, the distance travelled is maximised, referred to as Vbg (Velocity of Best Glide), there is also Vmd (Velocity of Minimum Decent), at this velocity your glider will remain in the air longer but it will not cover as much distance.

LE

Leading Edge; This refers to the front edge of the flying surface

TE

Trailing Edge; This refers to the rear edge of the flying surface

TLAR

``That looks about right''; A somewhat humored term referring to a design process whereby the designer has chosen a particular design mostly based on its appearances. The more experienced the designer the better their TLAR design ability typically.

14.4 Conversions

14.4.1 Lengths and sizes

Please note these values are approximations only.

Metric Length

Imperial 0.8mm

14.4.2 Weights

Please note these values are approximations only.

Metric weight

Imperial 28.35g

14.5 Further information

QFII Website http://www.pldaniels.com/flying/models/qfii