Blue Max:
It depends what you are envisaging the aircraft doing. I am not really convinced that we need a large "Strategic" airlift capacity. As George and many others have pointed out we are not going to be rushing Brigades around the globe a 24 hours notice. Even the Yanks can't do that with their available lift. Strategically I am much more comfortable with the notion of investing the price of 2 C17s in a Very Large Ship for use as a mobile warehouse (One C17 will buy you 45,000 sq meters of garage space on a RoRo and leave you spare change. 2 would allow you to invest in survivability technology for the ship and maybe some other goodies).
We do need "Strategic" lift to move spare parts, replacement vehicles and personnel, ammo and rations into theater and wrecked vehicles and kit, wounded and rotating personnel out of theater but that doesn't require surge lift so much as a regularly scheduled conveyor. Much of that movement can be done in "safe skies" using civilian lifters to cover the long "strategic" distances.
Once you get within a thousand kilometers or so of the fighting you are now down to tactical/operational distances. In those circumstances where you are now within 2 or 3 flying hours of the troops you still don't need large numbers of large aircraft, especially for Canadian deployments. You do need a few large aircraft that can ferry things like the LAV in and out. For these aircraft the dominant requirement is not for tonnage or volume so much as floor area and height. You also need aircraft that can lift small packages to varied destinations. For these aircraft tonnage and volume become the dominant drivers.
Look at it this way - one tonne of ammo boxes, about a pallet, can be broken down and stuffed into odd corners of something as constrained as an Otter. A LAV can't be broken down.
Either way its looked at I see Canada needing not so much aircraft with the ability to fly 'strategic distances' so much as shuttle aircraft. A small number need to be available to handle shipments like the LAVs, HLVWs and Helicopters - they can be used both domestically and internationally to shuttle kit forward - making up in frequency of sorties what they lack in numbers. A larger number of smaller tactical lifters capable of air drops and rough strip landing to keep dispersed small units supported, or which can be formed up into packets to deliver an airborne force, again over relatively short distances.
Domestically it is possible to get almost anywhere from anywhere in Canada in 4 to 8 hours. An Air delivered and supported force is a relatively cost effective way of ensuring that troops can be rapidly on scene to react to any situation - including a MAJAID deployment in the High Arctic.
The C27J is not a bad size to handle the frequent shuttles and small unit deployments as well as the FWSAR program. To be fair the C295 could probably also work - although some feel that it wouldn't do as well.
Shuttling large vehicles needs a large aircraft and in that regard we are down to the C130, A400 and the C17 (for those of us that wish to stick to "allied" suppliers - another story). Our C130s can handle much of our kit but it seems to be a squeeze and they are long in the tooth. Replacing them with the C130J would still leave the squeeze factor and would also limit the equipment that we could deploy.
Acquiring the C17 would remove the limits and allow for any vehicle or helo to be deployed but at a very high price.
The A400 would expand the limits so that we could lift anything we have in the current and anticipated inventory with the exception of helos like the CH147/CH148/CH149 and MBTs at a considerably better price.
Eliminating the "squeeze factor" because it means less time and effort on the ground (both for air and ground personnel) prepping, loading and unloading kit. It would also likely reduce the risk of damage to the aircraft and the kit.
All of the aircraft could self-deploy over strategic distances.
I don't really see the need for a Strategic Airlift Fleet as a need for a Tactical/Operational shuttle fleet that can lift outsize cargo as well as service dispersed small units.
It seems more effective to maintain a fleet of small aircraft that can be used on a daily basis and brigaded for large ops than a fleet of large aircraft that will either sit idle, fly mostly empty or else have to fly more infrequently thus reducing the timeliness of the support available.