Wight Lady (oz14833)

About this Plan

Wight Lady. Radio control sport biplane model. Wingspan 48 in.

Quote: "Your Full-Size Biplabne Plans. Build this 48 in span sports aerobatic biplane. Wight Lady, by Keith Humber.

We recently lost the use of our power flying field - the farmer needed to plough it - but he was however good enough to let us have the use of a rather rough area of grass (actually about four acres but long and rough) by way of compensation. So rather than damaging our more elaborate scale models, there arose a necessity for a light, quick to build fun model with a slow landing speed. Hence 'Wight Lady' was conceived; a nice, light, slow bipe not too big but with a light wing loading and a good sport aerobatic performance.

The aerobatic side of her is really a treat! She flies very soft around the neutrals but when more control movement is used she snaps like a Pitts. The only difficult part of the construction is the cabane struts and even that isn't too hard - which leads me on to a brief resume of the construction and high points.

Get cutting: Starting with the fuselage, cut a pair of basic fuselage sides from 1/8 sheet together with a pair of 1/16 ply doublers. Glue up with PVA or contact adhesive (make sure the sides are handed). Cut formers from 1/Sin ply noting that the rear turtle deck half-formers are 1/8 balsa.

Cut out a pair of 1/8 ply cabane mounts C1 and bolt to dural struts. Be as accurate as possible here because the wing incidence is aligned by lining the top of ply C1 with the basic fuselage sides. Glue each pair of cabanes to its relevant fuselage side then cut and frame up the engine bearers using epoxy.

Next frame up the fuselage sides on to the formers checking for alignment (the engine has approx. three degrees right side thrust). Cut out the tail group from 1/4 in sheet and glue the tail into position over previously glued in 1/4 in reinforcing doublers under the tailplane which support the tail junction. Glue the fin into position, cut stringers from 1/8 sheet and glue into position.

Plank the forward turtle decks with 1/8 sheet. The undercarriage is bent from 8swg noting the set on the short arms to enable the undercarriage to be raked forward. It is fixed into position with dural saddles, screwed to the grooved hardwood mounting blocks which are securely glued with epoxy.

The engine used on the original is a Saito 45 with a 4oz tank which is positioned through the round hole in the front former (you may have to cut a different hole to suit tank used). Position the tank before finally mounting engine or cut a tank notch over same. The dural cabane has ply saddles fixed either side to increase the width of bearing for wing mount. The wing bolts are threaded through brass mounts made from 13 amp plug pins drilled and tapped. These brass mounts are positioned in the middle of studdings which are fixed across the cabanes and lock-nutted into position.

Wings: The drawing and photos explain this better than I can - it certainly works very well! The aileron servo lead goes through a hole in the fuselage top to plug into the Rx.

The wings are also pretty simple. Cut tip and root ribs making up blanks for ribs then produce a set of ribs by the sandwich method. Note that the top wing has a progressive section, a trick I use on my aerobatic sailplanes.

Frame ribs up onto the lower spar gluing into position then add leading and trailing edges. Sheet the LE, top cap the TE section with 1/16 x 2 in cap strips then remove from the building board. Complete the wing in the hand checking for alignment. Note there is no dihedral under either wing. The ailerons are produced from 3/8 sheet carved to section and hinged with mylar or similar hinges. The lower wing is parallel chord and the original had flaps built in but they did not prove to be affective so I never used them and have deleted them from the drawings.

The underside of the centre section is reinforced with a piece of thin ply (to take the scuff of the wing mounts) but fibreglass tape would be suitable as well. The original model was covered in Solartex painted with car cellulose and fuelproofed with Tufcote.

Flying: Do make sure you check the CG and incidences. They should be OK but, if not, pack the wings to adjust. Both wings are rigged zero/zero but as the sections are different this means aerodynamically she isn't quite zero/zero! Next, check the direction of control movements; I still must admit to occasionally finding they are wrong sense, and I have been modelling since I was seven years old and that's 48 years ago! So re-check, it's worth it. If all is as it should be you really shouldn't have any problems so best of luck and I hope you enjoy Wight Lady, she really is a fun machine."

Wight Lady from Radio Modeller April 1991.

Direct submission to Outerzone.

Supplementary file notes

Article pages, thanks to RFJ.

Corrections?

Did we get something wrong with these details about this plan (especially the datafile)? That happens sometimes. You can help us fix it.
Add a correction