The Vladimir's Models Plus F5J
is a revolutionary glider that truly breaks the norms of F5J models. The twin boom and inverted V tail configuration has many benefits. The pusher propeller ensures the flow over the front fuselage remains laminar, reducing the fuselage drag and allows dork type competition spot landings with impunity. The centrally mounted motor minimises inertia, as do the short twin tailbooms and the light inverted V tail. The inverted V tail rudder action works in the same sense as the ailerons, giving into turn roll commands with rudder movement. This will give coordinated rudder/aileron control.
The Plus F5J wing is a masterpiece of aerodynamic and structural design, with new airfoils by Joe Wurts. The wing has a skin of spread carbon over a Rohacel core, and a strong carbon spar with a well engineered shear web, ensuring good strength despite the low weight. The twin tail booms have been superbly faired into the wing by Vladimir, eliminating a possible source of drag in this configuration. The wings has five control surfaces: a flap on the centre panel, flapperons on the mid panels and ailerons on the tip panels. These give superb approach control, allowing the model to be slowed down and spot landed with ease. The airfoils and wing planform were optimized for best thermaling and best wind penetration for an ultralight model, fully taking into account the low Reynolds numbers encountered. Joe Wurts’ airfoils allow a wide of flap use from -2 to +7 degrees to achieve maximum climb performance in thermals without compromising glide angle in normal and high speed cruise, ensuring the model can be brought back upwind after drifting a long way back in a thermal.
Inspired tail boom to wing fittings provide light weight and high strength while also simplifying airframe assembly on the field. The Plus F5J takes less than a minute to assemble and requires only two screws. The pull-spring V tail control system is very light, rigid, and guarantees no slop in the control surfaces, ensuring the model returns to the same trim state after up and down elevator commands.
The model is currently just available in a light spread carbon layup. However a ballast system is also available, allowing the model to be used in light and normal conditions.
The Plus F5J
has these unique advantages:
- Potentially the best thermaling performance for a model of this size;
- Superb L/D at cruise and fast cruise giving excellent wind penetration;
- Low fuselage drag with the propeller at the rear;
- Rudder movement also gives an appropriate roll command;
- Very easy handling;
- Ultralight weight;
- Compact size for easy transportation.
All of the Plus F5J models we supply have IDS sets already fitted to the wings, so the two aileron and the three flap servos can just be slotted into place in the custom Servorahmen bearing fames
. All our models have Standard
frames for KST X08H
aileron servos and HV6110
flap servos, though other servo options may be ordered. These IDS sets include ready fitted optimised linkages, as shown in the photo below. Our price includes IDS installation for all the wing servos, the motor drive shaft, motor drive shaft installation, spinner and folding prop blades, and Vladimir's excellent wing and tail bags. These are extra cost items from other dealers.
Ballast is not included in the base price, and must be purchased separately, as must be the servos, motor, ESC, receiver etc. Although the cost of the model looks high at first glance, the ability to use a low cost outrunner motor instead of a geared inrunner reduces the RTF cost by about £200 / €230 / $210 making it very reasonable for such an advanced airframe.
Lots more info and photos are visible on the Vladimirs Models site
and in this Plus F5J
RCGroups discussion thread. Also check out Larry Jolly's Plus Build Thread
© 2017 Neil Stainton
|Plus F5J Specifications|
||1108 sq in
|Flying weight from
||4.9 oz/sq ft
|Centre of Gravity
||88-96 mm from wing leading edge
||V tail, flap, flaperons, ailerons, throttle
|Plus F5J Typical Weights|
|V tail servos
|Flap servos (3)
|Prop & spinner
Note this is preliminary information and may be subject to change. Also the expected arrival date is only a guide and may slip.