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F14 picture


F14 Tomcat picture






A superb sport scale aircraft that lets you do all you would expect from a high performance jet style aircraft, yet is docile enough to land like a trainer.


by Adrian Hall

Introduction

The F-14 Tomcat was designed as a carrier based aircraft for the US Navy. With its variable geometry wings the speed range of the aircraft could be varied from slow for carrier landings up to supersonic speeds to mach 2.4. The role of the F-14 Tomcat was brought to the fore during the Gulf crisis in the early 90's.

The model

F14 picture

Jet modelling is a particularly exciting part of our hobby, but unfortunately due to financial restrictions, the reality of ducted fan and gas turbine driven models remains but a distant fantasy for many would be jet jockeys! Luckily thanks to the folks at Airborne the F14 Tomcat can be yours without the big bucks!

As a stand off scale prop driven model Airborne's F-14 Tomcat will more than satisfy the sport modeller looking for something different.

The F14 Tomcat is not a difficult model to build and definitely not hard to fly.

When the model flew throttled back it performed like a trainer but when the throttle was applied it went like a rocket!

Wing

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Some modellers would to prefer to make a kit from the plans, but I like to cut and paste as I go (you would think I was making a paper plane).

Most importantly the wing is built over the plan UPSIDE DOWN as one unit. The only dihedral is provided by the angle of the underside wing surface. The top surface is flat. Careful selection of wood will make for a strong and lightweight wing.

Begin by laying the top main spar down over the plan, and then adding the ribs, plywood joiners J1, J2, and J3 as you go. Next add the aileron spar made from 6.5mm hard balsa, followed by 9.5mm balsa shaped leading edge. The bottom spar can now be added, at this point make sure that the wing is sitting flat on your building board and all rib tabs (to be cut off latter) are also sitting flat on the board. Next fill the area between both ribs W2 at the trailing edge with balsa block. At this point it will be necessary to add the bottom sheeting and cap strips. Before removing the wing from the board cut the centre sheeting away to mount the aileron servo, use a standard servo installation as required. During construction I kept weights on the wing to ensure no warps developed.

Remove the wing from the building board and add the top sheeting along with the cap strips. You should now add your aileron torque rods prior to fitting the trailing edge piece, all that is left now is to add the wing tips and start sanding. Leave the wing dowels out at this stage (this will be covered latter), shape the ailerons at this point in construction to make a completed wing. Balsa fairings front and rear should be added during wing to fuselage mating.

Tailplane and fins

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These are very easy to construct and only require 9.5mm balsa to be cut and glued over the plan. The plywood servo tray is then cut to suit your servos and screwed in place as shown on the plan. The slots for the fins must be cut on a slight angle to facilitate a good fit. Make the control surfaces from 9.5mm sheet balsa, cutting out the lightening holes as you go. The elevator uses aileron torsion rods and are fitted in the same manner as the wing. At this point you will find it easier to make a template to assist in fitting of the vertical fins (refer to scaled down view on plan) do not glue vertical fins at this stage.

Fuselage

The fuselage construction is not as difficult as it first appears, the fuselage is constructed in two separate sections. The narrower fuselage/cockpit section is built into the wider main rear fuselage. Begin construction by cutting out all plywood formers from F1 through to F9, the front fuselage section can now be assembled using formers F1, 2, 2a, 3, and 4. The forward fuselage doubler should have lightening holes cut out prior to assembly, also add the 12.5mm balsa triangle at the same time, at this stage you can mount the radial engine mount as per plan using a tapered wedge to achieve the required down and right thrust (I opted to use an "Ernst" thrust plate).

The main rear fuselage section can now be constructed as a separate section beginning with formers F4, 5, 6, 7, 8, 8a, and F9 along with fuselage sides. Add the wing seating pieces as well as the 6.5mm square balsa followed by the 12.5mm balsa triangle running along the bottom fuselage sides, add the undercarriage hardwood blocks and wing mounting plate at this stage. Glue in the rear fuselage doublers. It's now time to join the two fuselage sections together on a flat building board.

F14 picture Once the basic fuselage assembly has dried you can then add the bottom sheeting along with pieces E1, E2 and E3.

The top rear deck and hatch can now be fitted. At this stage trial fit the tailplane assembly along with the two vertical fins, this will be necessary in order to obtain the correct fit for the top hatch. Finish the fuselage by adding the fin strakes and tailpipe pieces (you may opt to leave these pieces off until after covering).

The cockpit can now be constructed using a base piece from 9.5mm balsa, then adding pieces C1, C2, C3 and F3a as per plan. I opted to make the canopy a permanent installation, should you decide on this method you will need to fit out the fuel tank bay so as be able to remove the tank by sliding through formers F2 and F3. There's plenty of room inside for your hands. The tank floor will also need to be extended back to F3. At this stage trial fit the wing to the fuselage. The wing mounting dowls can then be fitted by drilling in through the front of former F3 into the wing for correct alignment. You can now add the top deck and extended rear deck made from soft balsa block to the wing, these two fairings remain part of the wing.

F14 picture The fuselage nose section is built up from 9.5mm balsa blocks and sanded to shape. The method I chose to do this was to mount the engine on the radial mount with the wedges in place, followed by tack gluing the 3mm plywood nose ring with an appropriate gap of 1.5mm to the 3 inch plastic spinner. This was then bolted to the engine crankshaft and the 9.5mm balsa blocks were then glued between the nose ring and the front of the fuselage. Finish by sanding the balsa blocks to blend in with the 3 inch black spinner.

The main undercarriage legs can now be bent as per the plan and the nose leg I used was a fixed nose leg unit which be purchased pre bent. I opted for a fixed nose wheel. Rudder authority is sufficient for steering when taxing.

Radio installation

The radio installation will be required to be kept to the rear of the model as much as possible. I installed the receiver and the battery pack between formers F8 and F9. The throttle servo was mounted midship using a single servo tray with a Bowden cable running to the engine. The switch assembly was mounted under the tailplane on the left hand side. The aileron servo can be mounted in the usual method as found in most sports and trainer models. Finish the installation by making suitable pushrods as per the drawings on the plan.

Covering & finishing

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You can choose your favourite method of covering bearing in mind that the full size aircraft was basically all over dull grey with a few exceptions such as dark blue, which is not a good choice with reference to orientation when flying. The prototype model was covered in all over grey profilm, adding only minimal decals for authenticity. A variety of common type military decals suitable for the F-14 Tomcat can be obtained from Western Flying School in Blacktown (NSW).

Install the radio gear again into the model, also fit the engine, tank and undercarriage in place.

Balance the model where indicated on plan. I found with positioning of radio gear alone the model could be balanced without having to add any lead.

The OS .46SF engine was test run and promised to deliver a high power to weight ratio for the F-14 Tomcat model.

Flying

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The day had arrived for the big test flight, the model was dually fuelled and pre flighted with all controls working in the correct sense. The initial test flight was perfect with the control throws being spot on, they were as follows. The elevator travel was 19mm up and down, the rudders were 15mm either side of centre, and the ailerons were set at 12mm up and 12mm down. The centre of gravity showed on the plan was just right.

F14 picture After quickly advancing the throttle I found the twin rudders were more than adequate for directional control on the ground. The model rose from the ground needing very little up elevator, indicating that the 1.5 degree positive wing incidence should not be exceeded. The model flew extremely well in almost any attitude, its slow speed handling characteristics were excellent, mainly due to the fact that the models total weight came out at 2.5 kilograms. Overall the model was a delight to fly. All the usual flying manoeuvres were tried, inverted flying! Now that was easy even at low speed. Knife edge? Well the model actually climbed under full power. Now that's different! Vertical climbs were very impressive, with several aileron torque rolls, stall turns, spins, flick rolls all performed well.

If you like the way a high wing trainer lands, you'll love this. With it's similar landing speed you can't go wrong. What more can I say, 'just right' like the cereal commercial. So push the trainer aside and start building. You wont be disappointed.

Acknowledgments

Thanks to the boys at Model Engines for the O.S. 46SF which performed flawlessly. Stars & trim supplied by Western Flying School, Shop 1, 31 Forge Street, Blacktown (NSW) Phone: (02) 9622 2790.


Look for these exciting plans in future editions of Airborne.
F/A-18 Hornet, F-111 and Extra 300s


F-14 Tomcat plans are available from:
Airborne Plans Service

AU$39.60 plus AU$2.00 P&H2

Moulded Canopy AU$27.50 plus AU$6.00 P&H2
Plan No. 629

Click here to order this plan

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This page was last modified on the 21-May-02