Guys...
Here is what I know about rocket powered models...
1. They MUST be built LIGHT.
2. Jets with twin engines will still be powered by ONE model rocket motor.
3. Jetex Motors are OOP and Raiper engines are NOT available.
4. Estes model Rocket Engines are designed for model Rockets, NOT model Jets.
Looking at the current line up in Guillow's Catalog I think the F-16a looks to be the best candidate for a rocket powered conversion.
I have a few model jet/rocket powered plane kits. They are from AreoMasters in the UK, EasyBuilt in USA. They are not expensive, and come with contest balsa. I built the skeletons, and plan to finish them as prop driven by rubber power. The Me-163 Komet and Bell X-1 will only be flown as gliders as the wing passes though the fuselage and prevents a rubber motor. I also have one OOP kit from Comet, the Cougar.
If anyone REALLY needs to make a Guillow jet fly... I would suggest buy kit 1403, the Falcon. Build it as a static model and then buy some contest balsa and use the plans and your knowledge to build a single engine jet... You will also need to make your own engine.
For now I am staying with Rubber Power. FAC rules allow modern jets to be flown with a propeller and rubber power.
Mitch