Gary Binnie

Just reading the first post again, ballooning implies the model nose is pitching up but the effect of positive flap is to pitch nose down and the elevator compensation is nose up to stop it. Or...if you've set some elevator compensation it was in the wrong sense. If the model is actually rising (fuselage level) then it could be carrying too much speed for the approach.

It's a standard mix for gliders, 'Butterfly' in your manual. That is generally using the throttle stick for flap deployment. Another way is Program Mix 4 which is a five point curve. The ballooning effect is strongest in the first 1/3 of flap travel (on gliders where the flaps lower to 80° plus) so the curve is set with most of the compensation happening at the start of travel. The settings are usually guessed or sometimes given as a distance movement by the designer (i.e. flaps down 50 mm, elevator up 5 mm) for the initial settings then the values are fine tuned by pulling the flaps and adjusting the values in the air or doing a series of flights and adjust the values between each. Another method would be to use flight modes but it looks like that transmitter doesn't have the facility. You could set one flap position and elevator trim for take off and another for landing (and a 'clean' wing position that I call 'cruise').

True, but on this BT Spitfire the controls are already designed to be internal. The flap linkage replicates the full-size by pushing a spring loaded door open on the upper surface of the wing as an indication to the pilot that the flaps are down (as they are split flaps they can't be seen from the cockpit). Using IDS for the flaps would lose the scale detail. The undercarriage has a similar system with pins that protrude from the wing, not replicated in the model. I've used a cut off servo horn for the aileron drive and the flap horns were made from Paxolin, I open up the linkage holes in stages to ensure there is no lost motion (0.1 mm at a time).

IDS is a pain, I took two weeks fitting it to a NAN Explorer glider (two flaps, two ailerons) and got unequal travel of surfaces (mainly the flaps) but could dial it out with my radio. Most composite glider manufacturers offer to install it at the factory, they use precision jigs and would be the way to go if I buy another one. The benefit of IDS (drag reduction) is debatable on a slow flying F5J glider, it's mostly psychological! There are plenty of 'thin wing' servos used for gliders and also frames to fit them in. Not sure if you've deliberately left off the anti-warp spanwise strip above the flap, you can see from my photo that the trailing edge is not supported once the jig tabs are removed from the ribs.

Was shuffling a few boxes earlier today and moved one of the BT Spitfire boxes, there are spare and unbuilt laser cut parts in there so I measured a rib for you. Rib 1A is 319 mm or 12 9/16" in chord. My laser cut parts were from Bob Holman in the States, the only accuracy problem I came across was some of the upper fuselage formers had been cut to the outside skin line, had to break them off and make replacements.

The plan could be distorted, it looks like you have a copy of a copy. The black lined border of the plan is for size checking, some designers write the size of the border on the plan. My BT Spitfire wing sheet border is 32" high and 49" wide. Without known border sizes you could check other smaller dimensions with a vernier caliper, the main wheel size on the plan should be exactly 3.75", I have even measured the width of strip wood parts on plans. This size is written in the bottom right corner of a Chris Foss glider plan.

I half built one then bought one fully built!! It's tissue covered and very fragile so it doesn't fly often. Some photos of the Phase Lift with my Hi-Phase and foam wing Centi-Phase (I have another with built up wings). Last photo is my Phase One that I've been working on recently, struggling with covering materials so it's gone back on top of the cupboard for now. Phase Lift controls as designed. Red servo is combined rudder and aileron, blue linear servo is for RS releasable tow hook and spoilers, and the servo across the fuselage is the trailing edge camber. Phase One

Some better images of a Phase 2, the photos are mine but the model is not. The fuselage is a balsa box. The Phase Two and the Mini-Phase are the last on my Phase list to build but that probably won't happen now due to cost and difficulties sourcing materials.

To save the grief of fitting and removing clevises multiple times during initial set up I use a clevis with the hole side cut off, when the correct length is achieved I wind the locknut up to the clevis to mark its position, then fit an unmodified clevis (once). I must stress that this is for workshop use only, I posted this on another forum and the readers didn't note what I had written, getting very negative about flying with half a clevis. I found some Multiplex clevises in a Multiplex glider that didn't have a pin, just two half spheres that gripped the holes in the servo arm, not seen them before and removed them quietly.

The two sanding jigs on the right were assembled from ply parts in my Goldberg Ultimate 10-300 kit, the one on the left is a copy made by me. The jig with 'E' and 'A' written on it was for chamfering the hinge faces of the elevator and ailerons, there must have been a rudder one as well?!! Jig on the right was for sanding the symmetrical leading edge.

I can think of just a couple of tips with trailing edges. If you sand a trailing edge strip to section before gluing it to the wing/tailplane it will curl up to the side that has been sanded. If trailing edges are sanded to a razor's edge the wood will be weakened and be prone to damage in transit to the field/slope and on landing. On a 100" span glider I would typically leave the trailing edge 1/16" or 2 mm thick, it makes no difference to the performance. I've contrived a photo to show how to get round over enthusiastic accidental sanding. The lower piece of wood is the edge of the building board or an old MDF shelf, the upper piece of wood is the sanding block. If the trailing edge is positioned slightly in from the board edge a right angle triangle space appears and the sanding block can't reduce the wood to a point. If the trailing edge distance from the edge of the board is consistent then the thickness of it should also be consistent.

It helps to stick your little finger out while cutting with a scalpel (like drinking tea at the Ritz!) and make sure fingers holding the steel straight edge are slightly back from the edge (or you will loose their tops!). If the skin has any grain then arrange for the knife to cut against the grain instead of with it as the knife will wander. With foam core ailerons sometimes ply is let in for reinforcement at the control horn, with built-up wings wedge shaped balsa sections can be inserted before facing to do the same job. If you are nervous about doing a particular job you could practise on a scrap model or build a short section of wing to sacrifice. These photos show the reinforcing for the hinge points and control horn on the Phase One.

I missed a photo from the Phase One build. The razor saw is used to separate the ribs which leaves 'stumps', a line is drawn on each rib stump from top skin to bottom skin using a 6" ruler then each stump is cut off as close to the line as possible. I used the razor saw for this, what is left can be easily sanded off.

Measure twice, cut once!! Fresh scalpel blade to cut the skins, steel ruler stuck to the wing with masking tape to ensure it doesn't slip then several light cuts. It doesn't matter if the ribs are cut into slightly, in fact it helps to some extent. Pins can be pushed through from top to bottom to double check that markings are accurate and the end faces will be vertical. These are photos from an Xtra Wot foam wing, same technique without the wing ribs, it has a balsa trailing edge which I think was supplied as a rectangular section. 1. Cuts marked out. 2. Making the end cuts, the bare foam is covered with a facing rib. 3. Sanding the facing strips level with the veneer skins, has to be done with the aileron in position and sanded spanwise with a long block to avoid dips. It's good practise to sit the wing on the foam bed that it was shipped in, built up wings can use foam beds from other model builds, there's usually one that fits (I throw nothing away!!).

For the leading edge, plane and sanding block. My model building standard improved by using larger sanding blocks (less likely to introduce dips/hollows). I use a 12" block that I originally bought from the Balsa Cabin. Below is a screenshot from a Multiplex glider instruction manual, the middle two images indicate planing and the lower is finishing with sandpaper. As it is a lifting section there is no centre. Ailerons and flaps are often built as part of the wing to ensure continuity of the aerofoil section and to maintain any washout (wing twist) that has been built in. These photos are from a recent build of a Chris Foss Phase one glider. 1. The wing is complete and the ailerons needed to be cut out, the pencil lines and shaded area shows what needed to be cut. 2. The skins were cut top and bottom spanwise and these strips were removed, I deliberately used little glue on the ribs where the skins needed to be removed. 3. With the strips removed the ribs were cut with a razor saw (vertically in the centre of the exposed portions). 4. The ribs were then carefully cut back and the faces sanded level ready for closing/facing strips. 5. Facing strips applied, the ailerons on this glider are top hinged, wing is inverted.

Adding some more photos of the Hi-Phase, in the previous one the upper spar is not fitted and I'm gluing in a balsa web, not ply. Panel on the right has no upper spar. The spruce spars are widened at the root for the increased stress, outer tip panels use balsa spars for weight saving. The built-up version of the Centi-Phase has spruce/balsa spliced main spars. Dry fitting ply webs loose in their rib bays before adding epoxy and closing up.

You can use a straight joiner if the slots for its tubes are cut at the dihedral angle in a hardwood spar filler. The first photo is of my Chris Foss 144" span Multi-Phase, the wood is Ramin from a local picture framing shop. The wood is laminated with thin ply, the longer ply part keys in to a vertical slot in the foam wing and glues to its single 1/4" spruce spar. The tube is epoxied in, I seal the open outboard ends with masking tape to stop it seeping in. It's glued in in one piece then cut in half after it's set for accuracy, there is an allowance for a ply root rib to be added, the tube is then filed flush. For a built up wing the wood block can be fitted between the upper and lower spars then closed with ply (Chris Foss Hi-Phase) I used quite large diameter steel rod for the Multi-Phase but for your model a 6 SWG wire joiner and aluminium tube would probably be ok. I have a chart somewhere of the number and size of joiners needed for gliders based on their wing span. Chris's 100" Centi-Phase uses a vertically stacked 6 SWG joiner system the same as this, the second joiner can be left out for gentle flying or not built in at all (i.e. not bungee launching in windy weather). Both designs use a thin incidence peg with aluminium tubes (14 SWG) to keep the root ribs aligned, I flew the Centi-Phase without it once and had a fun time trying to trim out strange roll behaviour!! I use carbon joiners in my competition gliders where they were manufactured with them but prefer piano wire for sport gliders as it only bends on a windy bungee launch, I've snapped carbon joiners before, they let go without warning. 1. Multi-Phase joiner system. 2. Centi-Phase system, upper wire is 6 SWG, lower is 8 SWG (and shorter than the main joiner). The incidence pin can be seen behind them. 3. Centi-Phase root rib. 4. The Hi-Phase uses three 6 SWG joiners, in this photo I have the wing vertical so that epoxy fills the space around the tubes by gravity. I have just added the ply webs fore and aft on the centre joiner. Instead of one piece of wood for the joiner it is short sections filling in between the ribs, hard balsa instead of hardwood. Extra tube is overhanging for the ply root rib to be added later.

Unlike a modern aircraft there is no colour coding on the airspeed indicator, tachometer or oil pressure gauge, there is no VSI (vertical speed indicator). Shiny knob lower right is the slat locking lever, only installed in the rear cockpit.

The limitation wording used to be on the CAA C of A but it's on the LAA system now with no limitations i.e. the rig is no longer used. There was a weight limit of 70 kg which, happily, I was above (didn't fancy it myself!) The fine pitch propeller limited the speed as it was easy to 'red line' the engine (except there was no red line, just a blurry tacho needle around 2,500 rpm).

The two brackets either side of the fuel tank are the rig attachment points. The cable running across the rear tube is the slat locking cable (locked in for spinning or gusty approaches, also locked while taxiing).

Andy - The airspace is the Brize Norton CTR. Martin - Rollason MOD WAR 75 is the walking on the wing rig, a lady member of our syndicate used to do it (since passed away). Have to fit a fine pitch propeller (also used for glider towing), all a bit of a faff.

I've got a lot of TM blueprints but I couldn't find the trim quadrant, they are for the Canadian DH82C which might have had a trim tab as opposed to a spring. I did find a 'tab' lever drawing. The altimeter is 80 mm/3" diameter. My map is 8 miles to the inch if you can zoom in! Would have a stab that the trim lever is about 10" from its fulcrum bolt to the shiny knob. Cheers Gary .

Happy New Year! I'm not looking forward to that bit! A tip (that I read from a book but I can't remember which one!) is to temporarily fill the gap in the fuselage with a dummy tailplane centre section spot glued in, you can then use a long sanding block or dowel to match the fuselage contour and fair better to the fin. Very damp in my shed and garage at the moment, too expensive to heat and not at all enticing!! 1. Balsacraft Fw 190 with dummy tailplane. The fin sits on the slab sheet tailplane so it's a good way to get it right anyway. 2. Chris Foss Xtra Wot: Like the Fw 190 the fin butts against the tailplane and a dummy fin allows the blocks to be sanded easily. 3. Looks great but sadly the fin was off centre, makes no difference to the flying thankfully.

Measuring the wheels on the plan their thickness is 1.125" or 28.5 mm. 3.75" is 95 mm.

Hi Laurent, The wheels came with the kit which I bought around 2002. The wheels are Len Gardiner items, 3.75" diameter. I can't measure the thickness as I can't get to the wing just now but they do just fit in the wing. The hubs are slightly asymmetric to allow the collet to be hidden by the hub cap. Virtually unobtainable now, I kept the label from the packaging. His website closed in 2008. The vacformed plastic hub caps are also his I believe. The plan says to use Robart 3.75" wheels so perhaps they have something close. Cheers Gary