Loaded Dice IIS (oz14701)

About this Plan

Loaded Dice IIS. Radio control FAI aerobatic model. WIngspan 68-1/2 in, for .61 to .90 engines.

Direct submission to Outerzone.

Quote: "Dear Sirs, I enclose herewith the Terry Westrop's Loaded Dice II S design; I got the plans from Nexus Plans Service years ago and I have never seen them in the web. I hope it will be welcome by the Terry Westrop fans. Regards, Javier L."

Update 25/7/2023: Added article, thanks to RFJ.

Quote: "Terry Westrop introduces plans for the latest stretched version of his outstandingly sucessful F3A aerobatic design.

Nineteen eighty four witnessed the introduction of the long awaited continuous schedules known as Turnround, similar in principle to full size aerobatics but somewhat less complex. Turnround was indeed good news for R/C aerobatics and was welcomed by the majority, undoubtedly a progressive step. The governing body of our sport, the FAI, do not always make decisions quite as beneficial for F3A and I believe the rule changes which take effect in 96 will make it no easier for aspiring pilots to take up a competitive route.

Those in contention at the top will have little alternative but to operate models appropriate for these new rules, ie two metre length or wingspan, 5 kg weight limit using any powerplant. Quite naturally two stroke competition motors of 20 - 25cc will emerge, along with 25 - 40cc four strokes wearing price tags that would normally adorn a good computer radio set. And so the 61 size motor that has 'contained' the size (and corresponding cost) of F3A models since time began will eventually become a rarity.

But for those many more who simply (for the time being) wish only to fly or compete with a design that is not so far short of the two metre models, this 'stretched' Loaded Dice will not disappoint. Although I have continued to operate the 'Hanno Special', albeit on even higher nitro fuels in order to maintain competitive power to weight, this version will accept the Super Tigre 90, OS 108 and, better still, the Webra 80 Competition. The Webra 80 mounts almost identically to the Hanno but the side exhaust motors can be mounted at 90 degrees, extending the firewall down to the base of the cowl and leaving the cowl as part of the fuz (i.e. do not cut the cowl away but remove sufficient material from the right side for the motor and mount). Do try to fit a soft mount system of some type, along with a reasonable prop - they are beautifully quiet and must prolong the life of the airframe and servos. Some details are included on the plan.

This latest Loaded Dice IIS was first used in anger on day three (normally fly off day) of the '94 Nationals and despite the severe cross winds and turbulence there was no doubting the superior presentation and flight characteristics. Had I not afforded myself the option of flying this stretched version of Loaded Dice 68, I might not have achieved that Nationals victory.

What's new: During the majority of any aerobatic programme the fuz is on view more than any other part of the airframe, so by increasing the fuz to almost 1.9 metres we find ourselves close to the new regulations for presentation value. With a revised tip section and a slight increase in wingspan, overall drag is minimised. It is noticeable that I still resist the 'need' for plug-in wings and an enclosed pipe. I believe in simplicity, accurate building, competent design and a nice looking model that fills me with the desire to fly with graceful precision.

A real floater: Always remember that Loaded Dice IIS has been developed to combat typical British weather conditions (ie high winds) encountered at competitions. The design's ability to cut through turbulence allows a good top speed to be achieved if required, however low speed handling is unquestionable. Due to the efficiency of the airframe, landings require a nose up attitude similar to that of modern jets, and for similar reasons, although we are not in the same league as the F-15 or Mirage when talking about attack angles on landings. A good indication of an ideal landing, so long as your model remains within the boundaries of the plan specifications and is not excessively heavy (over 9 lb), is to touch the tailwheel first. If you prefer to glide in flat, be prepared for a long approach.

Engines and pipes: This subject is not simple to explain in detail so I will endeavour to briefly describe the best route, not necessarily the most economical. Obviously the OS Hanno 61 is supplied with a Hanno pipe and, along with the stainless steel rear bearing and plated crankshaft, it is almost foolproof on any nitro fuels. The Hanno pipe is typical of the type used in aerobatics at present; the 'Hatori' long chamber is the equivalent (Hatori 700 pipe, I believe) - not so much a power pipe as a torque pipe. Consequently it is much easier to set up on any motor from an ASP or MDS 61 to a Webra 80 or Super Tigre 90.

This pipe, or tuned muffler to be precise, is very flexible in operation, light and beautifully made, though they are quite expensive. These pipes are intended for use at around 10,500 rpm static and with the motor soft mounted at this rpm it will prove extremely quiet, so you will need to prop accordingly. A standard RFP OS 61 would turn an APC 12 x 10 on low nitro at around 11,000 rpm, a 12 x 11 on say 15% nitro or more at 10,400. Carbon fibre pipes such as the Bolly EQ60 and EQ62 operate at similar lengths.

Manifold length starts at around 9 to 10 in. The quick way of finding the most efficient pipe length is to have a number of props, all the same make, that you feel the motor will accept..."

Supplementary file notes

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