Elf (oz3825)

About this Plan

Elf. Semi-scale pusher model for CO2.

Quote: "Build this modern free flight fighter model for CO2 .power designed by George Mathieson.

Having often been struck by the almost complete absence of plans or kits for flying scale models of present day combat aircraft, I determined to make a serious attempt to design such a model. Two earlier models, a MIG 29 and a Saab Viggen were built and although not entirely successful a number of lessons were learnt that have made this model a success.

Although the F-16XL, as far as I know, never got into service, the general format is typical of the modern combat aircraft. On this basis, starting with a wing of adequate area to keep the model wing loading down to under 4 oz/ft, the 'ELF' design was tailored to an F-16 family resemblance, but with simplified lines. The concept proved to be quite untempremental, and with it's light wing loading and low drag it has an adequate climb and a very flat glide looking very realistic in flight.

Not having attempted to keep weight to a minimum (it's 80 grammes) it is on the heavy side for the standard Telco, so I changed the gas tank to a Brown one of 6 cc, which gave durations of over 1-1/2 minutes. An additional Telco tank may be fitted if desired, total cost including extra tubing is about £1.50.

Fuselage. This is essentially a 1/16 in balsa rectangular box with an intermediate deck of 1/16 in balsa. Start by cutting out the ply formers, F2 and F4 (engine bulkhead) and balsa formers Fl, F3. Former F2 also has attached to it the bracket for the engine charging nozzle, on both F2 and F4 epoxy the appropriate mounting nuts in place, as it will be difficult to deal with loose nuts at a later stage. Next cut out the vertical fuselage sides from light sheet. Note that the vertical sides incline down at the front, level with the top of the nose yoke.

After marking the position of the formers, the vertical stiffeners are glued on, ending 1/16 in inside the outer edges to accommodate the horizontal stiffeners. Cut the nose yoke from hard 1/16 in balsa, and intermediate deck from medium grade, not forgetting to notch it's edges for the vertical stiffeners. The slots to accept the wing spars should be cut out at this stage, and a trial fit of formers, intermediate deck and the nose yoke to the sides.

The front forward of F1, is not pulled in yet. If everything is satisfactory, glue to one side and leave to dry. The bottom sheeting between F1 and F2 is glued in next, then the other side. After the bottom and top stiffeners, fit the rest of the bottom sheeting. The sides forward of F1 are 'painted' with water on the outside to assist in bending and glued (with PVA) to the nose yoke (hold in place with a clothes peg). Fit the aluminium tube socket for the nose undercarriage leg as shown. The tank plate of 1/32 in ply should not be too snug a fit or it will prove difficult to insert and extract. Note that the top of the fuselage is left open, and should remain so until the wing is glued in place.

Wing. The main spar, top spar, and trailing edge extend to the centre line of the fuselage, but the leading edge is cut short to the inside of the fuselage side sheeting. The main spar is in two sections with an overlap between ribs R3 and R4. These spars, together with leading and trailing edges should be fairly hard 1/16 in sheet. Notch the trailing edge for the ribs and make the main spar as shown. Build the inner wing panels flat on the plan. Note the reinforcing root rib flange of 3/16 in x 1/16 in and the diagonal brace of 1/4 in x 1/16 in between this and the top spar..."

Quote: "We look this time at the February 1985 AEROMODELLER The cover features the CO2 powered ELF. A full size plan was to be found inside... The model featured on the cover for CO2 power is next it's the ELF. It seems that STEFEN GASPARAN has started manufacturing his great little CO2 motors again being available direct from him or through COSMIC FLYER on EBay. Elf was designed by GEORGE MATHIESON to resemble the F-16 family of fighters and as can be seen by the cover looks great in the air. All details are in the article and on the full size plans."

Supplementary file notes

Planfile includes article.

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