How big does my model have to be to be "Giant Scale"

Canadian standard: A Giant Scale Model Aircraft as defined by MAAC as a model aircraft with a total flying weight not-to-exceed 35 Kg (77 lbs) and with:

  1.  minimum wingspan of 2.0 metres (78") for monoplanes;
  2. minimum wingspan of 1.5 metres (59") for Biplanes/Multi-wings;
  3. 3.5 metres (138") total length plus wingspan for jets; and,
  4. all true scale models of 25% scale or larger.

USA standards: The AMA flying weight limit is the same as in Canada: 35Kg (77lbs, 2 oz). The AMA does not have a 'Giant Scale' Special Interest group with published documents so the original IMAA (International International Miniature Aircraft Association) model definition is ....

  1. Minimum wingspans of eighty (80) inches for monoplanes and sixty (60) inches for multi-wing aircraft.
  2. Ducted Fan and Turbine aircraft with one hundred forty (140) inches combined length and width, measured from wing tip to wing tip at the widest point perpendicular to the fuselage and added to the length of the fuselage, excluding any protrusions.
  3. Autogyros with 50 inches for a single rotor, 80 inches for a dual rotor.
  4. Quarter (1/4) scale replica's or larger with proper documentation (minimum 3 view drawing of an actual person carrying aircraft) which do not fit the size requirements will be permitted.

Other Notes:

The term "Giant Scale Legal" printed or advertised on many commercial kits or ARFs can be misleading. To be truly "Giant Scale Legal" there are standards of construction, linkages, battery size etc that also need to be observed. We have seen large sized model kits with totally inadequate hardware. Hopefully this will become the rare exception!

The MAAC Giant Scale Committee became the Large Model Committee at the 2018 annual general meeting, but otherwise no other aspects of Giant Scale modelling has changed 


What's a "kill switch" and why do I need it?

The MAAC Large Model Safety Guidelines has two things regarding the ability to "kill" or stop the model engine.:

The first is the ability in flight to be able to cut or kill the engine. This usually is done by setting the throttle up so that full low throttle trim on your transmitter will lean out or stop the engine. A good safety feature!

The second is a "kill" switch that refers to the ignition switch on gasoline engines. This is similar to full size aircraft ignition or mag' switches. On magneto ignition systems this is a switch that in the "safe" or "kill" position is actually shorting out the magneto coil primary circuit to ground or the engine crankcase. On newer electronic ignition systems this switch connects its battery power to the ignition circuit. In the "safe" or "kill" position this would be off or open contact.

The kill switch has to be readily accessible especially to your helper to kill the engine if needed.

The main purpose of this switch is to prevent inadvertent firing of the engine. This is especially needed when turning the engine over for priming or for safety reasons when the plane is in the pit area or on display.


Can I learn to fly on a "Giant Scale" model?

Yes you can! It isn't the way most of us got our wings but it can be done. It really depends on your local flying site and your instructor. There are a number of 'trainer' type aircraft out there in ARF, Kit or built-from-plans that are appropriate.

Starting right off with a gasoline engine would save you the expense of the glow engine and required accessories. Also in today's marketplace the larger planes, heavier duty servos are in the same ball park as smaller planes. There's a quarter scale Eindecker with converted weedeater engine that comes in under $150.00.


What kind of oil do I use on my gas engine?

This really depends on the engine manufacturers recommendations. Usually the modern high performance engines require you to use petroleum based oil for an initial break-in period. This can be for up to the first 5 gallons of use. This doesn't mean that you can't fly. The best break-ins are in the air under the varying loads of actual flight. These oils are those like Penzoil 2 stoke or a non-synthetic 2 stroke lawnmower or chain saw oil.

After the break-in then you should switch to a synthetic for cleaner burning. There are several brands out there. It's best to ask the experienced big bird flyers in your area. A popular choice is the Amsoil 1:100 mix. But remember, like everything else you can't go wrong by reading the instructions!


How can I minimize "noise" interference from my gas engine?

Electronic noise was the big 'bug-bear' in the early days of working with gas engines. Today the modern receivers are much better in this regard. Also modern electronic ignition systems have shielded plug leads. However it pays to observe some simple rules to avoid electronic noise from ruining your big bird. Here are some hints to follow:

If the engine has magneto ignition keep everything connected to your radio at least 12 inches away from the magnet, especially the battery!! Batteries are great inductors for noise.Use a resistor or suppressor type spark plug.

The Kill switch is also a source of current and noise when the engine is running. Keep your radio and its connectors away from it.
Use a non-metallic throttle linkage. This is where 'nyrod' is good.
Even with shielded' electronic ignitions, keep your radio as far from the ignition module and its battery as possible.
Do conduct a range check with the engine running before you fly. You should get the same range with or without the engine running.