Class 1 Carrier Deck
So what's Class One all about?
Class1 is the high tech Carrier event! Unlike the beginner's class of Basic Carrier Deck, the rules for Class 1 are much more stringent and not only require scale fidelity but also emphasise high speed; for maximum scores models must be proper scale representations of full size Carrier aircraft and capable of flying at very high speeds. Slow flight subsequently has to be achieved by using all manner of complex low speed/ high lift devices, eg: moving flaps, ailerons, rudder, line sweep, slats, slots and dive brakes; even retracting undercarriages are not unknown. Engine power is a major factor in this class, and whilst tuned exhaust systems have been banned to avoid excessive engine operating complexity, Class 1 definitely means horsepower! This, together with the various devices that have to be ingeniously squeezed into the airframe, means that Class 1 is most likely to appeal to the mechanically minded aeromodeller, the 'engine' man and the scale enthusiast.
Class 1 rules and contest calendar
You'll find the Class 1 rules on a subsequent page on this site. The UK/European contest calendar will also be published here as soon as it is available. The rules and calendar are provided in this way so that annual rule alterations and each new year's contest details can be easily incorporated.
What sort of model is needed to fly in Class 1?
A Class1 model is a proper scale model, built to a maximum of +5% linear accuracy (Rule 8). This tolerance is allowed so that the simplification of complex shapes can be permitted. Furthermore, although the major components and control surfaces of Class 1 models are subject to this requirement, the high level detailing required on pure scale models is not necessary. Class 1 models are therefore scale, but at a level of detail such that construction does not take an excessive amount of time and effort. It is also perfectly possible to use a model which does not satisfy this rule, but the scale bonus of 100 points will be forfeited and this invariably means that non-scale models cannot be competitive. Within the scale requirements and subject to a maximum weight of 4lbs, a mamimum engine capacity of .40cu.in. and a span of 44", Class 1 is a no-holds-barred contest class!
Whilst BCD's rules emphasise slow flight and encourage large models with high lift (and high drag) wings and merely ordinary throttled engines, Class 1's rules do the opposite! Class 1 models therefore tend to be much smaller than their BCD counterparts to minimise drag, with wings designed for high speed and low drag rather than low speed and high lift. Engines can vary from normal R/C types (but always selected for high power), right up to full-house racing engines best described as high nitro-consuming fire-breathing plug-crunching beasts!
This emphasis on high speed means that good low speed performance from a Class 1 model can be much more difficult to obtain and this in turn means that successful arrested landings are simply harder to achieve.
To get adequate low speed performance from what is essentially a racing wing design, the rules permit the model to replicate and use all control surfaces featured in the full size aircraft. Flaps can therefore be used to increase lift and drag, and the actual flap systems used in the full size prototype may be modelled, permitting designs from plain flaps, through increasingly complex (but increasingly lift- and drag-enhancing) split, Zap and slotted flap types, to the extremes of Fowler or Fairey-Youngman area increasing flaps.
Extra slow run line tension can be obtained by using ailerons to roll the model outwards, a flip-over rudder to yaw the model outwards and moving the leadout position rearwards also to yaw the model outwards; the latter being known as line rake or line sweep. Slats or slots can be used for boundary layer control to reduce the stalling speed of the wing and dive brakes may be used to provide extra drag.
Whilst relatively heavy, retracting undercarriage has even been used to reduce high speed drag during the fast run, subsequently being lowered for extra drag during slow flight. Whatever devices are used, they have to be packed into a small and (usually) thin wing and small fuselage. Not easy!Class 1 models are usually sufficently small for the protruding .40 engine to seem almost ridiculously large. This is quite normal - not for nothing have these models sometimes been called scale rat racers! Scale requirements dictate that engines and silencers must be very closely cowled, dihedral must be similar to the full size aircraft modelled and the undercarriage must exit the airframe at the scale position (although it need not be to scale thereafter). Class 1 undercarriages therefore usually have to be wing mounted and the supporting structure needs to be properly thought out if it is to cope with the forces arising from the 'controlled crash' of a typical arrested landing, whilst still fitting inside the wing structure. The undercarriage legs themselves are invariably raked forward for extra stability to take maximum advantage of the meagre relaxation of the rules in this respect.
The only major rule concession to non-scale practicality is the arrester hook itself. As in BCD, it is permitted to be up to 1/3 of the fuselage in length, in recognition of the fact that arrested landings using a scale hook would otherwise be extremely difficult.The speed control systems used in Class 1 models are no different to those described earlier in BCD; reference to Section 4 should therefore be made since there is no need to repeat such details here. Again, the most popular arrangement is invariably the J.Roberts inspired 3-line system and it's modern and commercial derivatives.
The design of a Class 1 model is an entirely different matter to that for Basic Carrier Deck. BCD allows almost every feature to be varied provided that this can be done within the constraints of the 'scale-like' appearance required by BCD's rules, whereas the Class 1 designer can alter almost nothing by virtue of the scale fidelity requirement. Instead, choice of the best geometrical and aerodynamic arrangements can only be made by selecting the most approriate full size prototype.
The only scale departures the designer is permitted, and even these are by convention and not enshrined within the rules, are changes to aerofoil section and wing thickness. Thereafter, the designer may (perhaps) make use of the +5% linear scale tolerance to simplify model shape, he must decide which of the prototypes low speed/ high lift devices he wants to use and how they will be operated, he must design the internal structure to cope with all the stresses likely during flight and on landing, and - finally - he must somehow squeeze in engine, fuel tank, control system and all the other weird and wonderful mechanisms that he hopes will make his model perform better than anyone else's!Convert an old model to fly in Class 1
If you already have a proper scale model of a navy carrier aircraft and the model is of the appropriate size, it is theoretically possible to add all the typical Class 1 systems - provided you are prepared thereafter to hazard it in the rough and tumble of real deck landings! In practice, however, the amount of work required to modify a typical scale airframe for a speed control system, a hook, sufficient low speed/ high lift devices to make the slow run competitive and adequate strength for heavy landings (that's heavy landings...) is usually enough to make the construction of a purpose built model from scratch a preferable alternative. Converting an old model is therefore seldom the best option unless you happen to be lucky and already possess the right type of spare model.
Class 1 Rules
Design your own Class1 model
Existing Class 1 designs
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