A Fletcher for Flight Sim
by Deane Baunton - - behind the scenes
I have always found something appealing about agricultural aircraft, the rugged functionality of their design and the exceptional skill of the pilots who fly them. Ag planes are designed for a purpose and in New Zealand, our most important export industry – agriculture, would struggle to exist if not for the aerial topdressing industry.

With almost 22 years serving in the Royal New Zealand Air Force as an Aircraft Technician, one might think that my interests would lie in designing military aircraft, but with most of these already modelled, I decided to focus on the aircraft types not yet done and the Fletcher was a New Zealand icon that met my requirements. Additionally as a modeller, I only get motivation for projects which I have an interest in, anything else becomes mundane, tends to drag on, and often results in compromise just to get it finished.

The Fletcher is an aircraft I have always loved, so modelling this aircraft was an exciting challenge.

Designing for FSX

When I started designing for Flight Sim, back in 1998, the Fletcher was one of the aircraft I wanted to build and my early releases served the purpose, but time marches on and every new release from Microsoft means designs become quickly outdated. After some years of designing scenery and helicopters, the release of FSX and some requests from other flight sim enthusiasts, prompted me to design the Fletcher all over again. One of the things that I liked about FSX was the level of detail now prevalent in the virtual cockpits and the fact that 2D cockpits were virtually redundant. For that reason I decided the cockpit would be the focus of much of the design and detail.

Aerial Topdressing in New Zealand

Think of agricultural flying and in most parts of the world the term “crop dusting” comes to mind, with thoughts of yellow biplanes flying low across vast plains of crops, but here in New Zealand it’s a different story. Ag flying is predominantly about topdressing, the spreading of granular fertilizer across the steep back country hills, flying from rugged airstrips often located on sloping ridges or carved into hillsides. In 1949 the topdressing industry began with ex WWII pilots flying cheap wartime surplus Tiger Moths. These aircraft were able to spread fertilizer far faster than traditional methods using men, packhorses and sleds!! But the stakes were high, the Tiger Moth was not ideal for the task, struggling, often overloaded, the crash rates were high. The search for the ideal topdresser ensued and soon other aircraft like Cessna 180’s and de Havilland Beavers were imported for use, but none would prove as successful in New Zealand as the Fletcher.

The Fletcher cockpit is relatively straight forward as it has a flat panel and basic construction. I lacked a lot of detail, but I was able to visit both Super Air at Hamilton and Wanganui Aero Work to take pictures of cockpits. Phoenix Aviation in Southland also provided a good picture. I am indebted to these operators for their help in this regard. The resulting instrument layout in my models is a mixture of elements from all the aircraft I have seen, there being no true standard layout to follow.

It is worth pointing out that I have always used Flight Sim Design Shop (FSDS) from Abacus to build 3D FS models (both aircraft and 3D objects for scenery). The alternative modelling tool is GMAX, which has some better features, but I have found it far too complex in use. GMAX takes advantage of all the latest features in FSX, whilst FSDS is not too far behind. I am not the only designer anxiously awaiting the release of FSDS version 3.5 for FSX in the near future.

After doing all the initial 3D modelling of the externals and internals, the first design challenge I faced was animating all the cockpit controls. I had animated controls previously with my Iroquois model, but only for the basic flight controls. Now, I wanted moving switches, a working starter, moving rods and cables, etc. A lot of time was spent absorbing material in the Microsoft SDK and online design forums to gain answers as to which animation tags and variables to use, not to mention trying different methods. More time was spent making changes, compiling, exporting and then starting Flightsim, only to get the wrong result and have to repeat the process – such is the fun of FS design!

The basic instrument panel typical of the 400 HP Fletcher. Only the use of GPS has brought the cockpit up to date.
The basic instrument panel typical of the 400 HP Fletcher. Only the use of GPS has brought the cockpit up to date.

The second challenge was making the gauges. It was easy enough to “borrow” some from the default Microsoft aircraft, but to get accuracy this was not always possible. Once again I needed to spend a lot of time to understand the newer XML format. I must admit I do like the new format, the BMP files for the artwork are easy to access and modify, but the syntax in the XML files is not always easy to follow so I modified default gauges rather than make my own. The only exception was the fictional “Agmaster 5100” display which I made from scratch as an exercise. It proved useful as a display in lieu of an agricultural GPS display.

The Fletcher has a jump seat for carrying the loader driver or the farmer. Note the mirror on the wing to monitor the flow from the hopper.
The Fletcher has a jump seat for carrying the loader driver or the farmer. Note the mirror on the wing to monitor the flow from the hopper.

Another aspect I wanted to try to duplicate was the aircraft load and subsequent loss of weight as the load of fertilizer was spread. This would enable the user to take off heavy and land light once empty. The solution had eluded me for a while until I saw a variable for water ballast which was used in the FSX glider. After studying how the ballast was set up for the glider I was able to modify the variable to increase the payload weight and rate at which the weight (load) was dispersed. It also has the advantage of being able to be turned on and off in flight, simulating the opening and closing of the hopper outlet at the end and beginning of sowing runs.

A good all round view is offered by the clear canopy. All the controls in the model are animated.
A good all round view is offered by the clear canopy. All the controls in the model are animated.

The remaining aspects of the design were relatively straight forward. The external model used standard animation, although animating the shock struts and wheels took some time. The textures did not pose too much difficulty either and this time I tried a new approach, using layers in my master texture files. This allowed me to have the base texture for the aircraft (in a plain white paint scheme), with additional layers for the colour scheme and the dirt and mud. This makes for easier re-painting and sped things up considerably.

A take off roll with 400 HP, a notch of flap and the aircraft empty - the take off roll will be short.
A take off roll with 400 HP, a notch of flap and the aircraft empty - the take off roll will be short.

With all those elements in place the 3D model was basically complete, but no FS aircraft would work without sound, flight dynamics and effects. The sound files were ‘borrowed” from the default FSX Beaver as the sound was as close as I have heard to an eight cylinder Lycoming, the flight dynamics tweaked from my original Fletcher and the topdressing effect modified from one I had done for my Iroquois.

Up at dawn, pre-flight completed and ready to start up for a long day of work.
Up at dawn, pre-flight completed and ready to start up for a long day of work.

After many months of “on and off” design I am more than happy with the outcome. Sure it is not perfect and I could do more. I’m still waiting for the purist who notes that the oleo extension is half an inch too long or the rivet spacing being inaccurate! There are no night light effects as I felt it was additional work I did not need, especially as agricultural aircraft are normally restricted to flying within daylight hours. I’m happy my focus on the VC paid off and this is backed by the fact there are more polygons used to model the VC than for the exterior model.

Lets go Flying

The Ideal Topdresser

The Fletcher was designed in USA, the result of a visit to New Zealand by Wendell Fletcher, who promised to build an aircraft in less than one year! Jim Thorpe who had designed the Fletcher FD-25 Defender, adopted the design to produce the Fletcher FU24. N6505C, the prototype was completed in 1954 and was imported to New Zealand as ZK-BDS flying for Robertson Air Services at Hamilton. The Fletcher differed from the normal tail-dragger configuration common amongst ag aircraft, but the tricycle undercarriage is well suited to New Zealand’s rugged twisting airstrips. To secure the design contract 100 kitset aircraft had to be purchased and these started arriving in New Zealand in 1955. Over the years several improvements and powerplant upgrades have taken place, the most significant was in 1970 when the 400 Hp engine was fitted. In all, 306 Fletchers were built with no less than 18 different power plants having been fitted over the years. The Fletcher has had it critics and while the perfect aircraft may never be found, after more than 50 years of flying the Fletcher still lives on.

One of the great things about the diverse range of aircraft in FS is that there is something for everyone. I have never been one for flying the heavy iron. That’s not to say from time to time I don’t enjoy flying the big jets, but for me flying by the seat of the pants is where I have the most fun. To be quite honest, because of the time spent designing, my time spent flying is limited to minutes at a time mainly testing my designs anyway.

The first thing to consider when flying the Fletcher is its role – it’s a weight lifter. A powerful engine and high lift wing means it can haul one ton of fertilizer off a short strip. Whilst at empty weights the performance is rather sprightly, don’t expect this aircraft to be a cross country cruiser!

The ag pilot is an early riser, up to work before first light, ready to take off at dawn to make the most of the day. Luckily we simmers can start any time we like. Your first task is to fly to the airstrip on or near the farmland to be top dressed. The loader truck is still there from yesterday and the loader driver is squeezed into the cockpit beside you. Don’t forget your lunchbox and thermos!!! After the normal engine warm up and checks you roar down the airstrip at your home base. Wind direction (what little there is) does not influence the take off direction as you have performance to spare.

Once airborne, there are no fancy instruments to navigate by (except GPS may come in handy) and with thousands of hours experience in the area the farm strip is easy to locate. A quick pass shows all is clear, with no stock or other obstacles on the sloping strip, so its time to circuit back for landing, mindful of the close proximity of the surrounding hills. You always land up hill and once lined up, with full flap, adequate power and speed need to be maintained as speed will bleed off quickly in the flare. You are careful not to go too slow (on steeper strips you might not make it up to the loading area) or too fast as you may overrun the short strip. A routine landing ensues and you taxi to the loading area to start work.

Loaded and ready to go. Placing airstrips high in the hills saves time in climbing, but normally means a sloping strip. On a steep strip like this you need a good sense of direction, you don’t want to accelerate over the brow and find yourself pointing in the wrong direction!!!
Loaded and ready to go. Placing airstrips high in the hills saves time in climbing, but normally means a sloping strip. On a steep strip like this you need a good sense of direction, you don’t want to accelerate over the brow and find yourself pointing in the wrong direction!!!

As the loader driver starts the loader and prepares the first load, you scan the gauges, adjust your sitting position and straps, grateful for the extra cockpit space with just one occupant. The first load of the day is reduced slightly, no point in over doing it with a full load just yet. It takes just seconds for the fertilizer to drop into the hopper, the aircraft lurching as the tail drops and nose rises. The loader backs away, you check flaps are set to take off, full throttle and you are away.

The downward slope assists acceleration, with a fully laden aircraft you don’t want any problems here.
The downward slope assists acceleration, with a fully laden aircraft you don’t want any problems here.

The downward slope helps aircraft acceleration, which you monitor carefully, ready to dump the load if you don’t look like getting airborne before the end of the strip. The plane becomes airborne, dropping into the valley at the end of the strip and as airspeed builds, slowly climbing as you turn to the area where you will begin sowing. The advent of the AG GPS and plotting makes it easy to find the start point (though not in FS yet!) and once you reach the place you finished yesterday, its time to begin.

What the job is all about – spreading fertilizer on the hills to keep the countryside green and productive.
What the job is all about – spreading fertilizer on the hills to keep the countryside green and productive.

With speed and height adjusted accordingly the hopper doors are opened and the sowing run begins. You can monitor the spreading by looking at the wing mounted mirror and as the load is spread you will need to adjust trim as the load lightens. At the end of the sowing run, the hopper is closed and you immediately begin a tight climbing turn, to bring the aircraft around 180 degrees to start the next run. After a few minutes the hopper is empty and its time to return to the strip for another load.

Not as easy as it looks, your approach is very flat and when you flare you will lose speed quickly.
Not as easy as it looks, your approach is very flat and when you flare you will lose speed quickly.

Once again you are mindful of the approach and never afraid to “go around” if required. Once on the strip, you taxi to the loading position and with a small burst of power you swing the aircraft around and await the next load. Within seconds the loader approaches and dumps in other load of super phosphate. The weather is looking good it and you know to take advantage of the good weather, it will be a long day. You push the throttle forward for another take-off, one of many you will make today.

A big difference at the pointy end – a 550 hp turbine is not only more powerful, but it is lighter and uses cheaper AVTUR fuel. This means better performance and better production. Look out for the Walter Turbine Fletcher soon.
A big difference at the pointy end – a 550 hp turbine is not only more powerful, but it is lighter and uses cheaper AVTUR fuel. This means better performance and better production. Look out for the Walter Turbine Fletcher soon.

More Production

In the real world, the quest for more productivity and economy has meant most operators are upgrading their Fletchers with Turboprop power, either by retrofitting turbine engines or upgrading to newer aircraft such as the PAC Cresco and XL750. It follows that I should also do the same and therefore I am currently working on a Walter Turbine conversion of the model.

Having gauge view problems in FS2004?

FS2004 users will find that not all the gauges show up. This is because some FSX gauges are not backward compatible. A panel fix can be downloaded from www.flightsim.com or www.avsim.com.

I had thought that modifying the model would be relatively straight forward but it has taken some time. As well as modifying the nose area, I have to do a lot of work on the virtual cockpit, the most obvious being changes to the engine levers and new gauges. I hope to release the Walter turbine Fletcher in coming weeks. After that I am looking at designing the Fletchers big brother the Cresco.

For now – I hope you enjoy the thrill of low level ag flying and I hope to continue to support this with my models. Look out to increase your productivity soon!!!

Links with more information on aerial topdressing in New Zealand

http://www.superair.co.nz/
http://www.phoenixaviation.co.nz/
http://www.aerowork.co.nz/
http://www.aerospace.co.nz/


Deane Baunton
About the author:
Deane Baunton has been a keen flight simmer since FS5. He is one of the leading New Zealand designers in the MSFS scene having started in 1998 and has created many aircraft and scenery packages for New Zealand. Currently serving with the Royal New Zealand Air Force at Woodbourne Air Base, he and his young family reside in nearby Renwick.
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