It is becoming customary that models do not include drop weapons, which forces modelers to find different solutions. In particular, I like to build my models in a clean aerodynamic condition, that is, without all the drop weapons. I very rarely add this to them, (except to Torpedoes and Dive Bombers), there are aftermarket parts for whoever needs them.
But not always, for example, the huge RAF Grand Slam or Tallboy bombs are not included in almost any model and there are absolutely no aftermarket ones.
So the easiest solution is to make them from scratch, and that's how I did my Grand Slam, using the auxiliary fuel tank of an Airfix Tornado, which has the exact ellipsoidal shape, I guess they took advantage of the aerodynamic studies of the pump to make the tank.
First you have to remove the rudder from the tank:
Then you have to add the four fins, note that they are not aligned, but deviated, the object was that they rotate when falling and thus acquire greater speed and stability. I made mine of thin plastic, from the lid of a glass of cream
They are glued on with white glue, (or cyanohydrochloride if you like to use it)
The bomb is painted, the colors are RAF Dark Green and RAF Ocean Grey, although I have also seen photos in which the pump is completely painted in green.
The painting details are:
Steel Nose
Two lines in front of the bomb, one red and one green
In several photos I have seen that many of the current ones do not follow that band code, but I assume it is by mistake.
And finally my Grand Slam looks like this:
