Jet-x & Rapier FAQs

The purpose of this page is to try to answer those frequent questions that I receive. Hopefully it will save you time and ensure that I give consistent answers. If there are other questions that flow from these questions please ask.

Q1. How do I manage when I run out of Rapier fuse?

A1. This should not happen as each pack contains spare fuses. The best way is to break the fuses in half, this should ensure plenty of spares.

Q2. My Rapier fails to ignite, what is the solution?

A2. Take a piece of wire that fits the nozzle. File the the end flat like a screwdriver. Insert the wire and twist into the propellant, this will ensure a good fit with the fuse. Insert fuse and now more failures!

Q3. What are the optimum sizes and weights of models for each size of rapier motor?

A3. See table below:-







0.8 ozs

1.2 ozs

3.0 ozs

4.0 ozs

Wing Area

30 sqins

45 sqins

100 sqins

130 sqins

Wing Span

10" - 12"

11" - 13"

14" - 18"

15" -20'

Q4 Can I mix old Jetex and Jet-x products?

A4. Be aware that the new Jet-x products are not compatible with the old style Jetex. The new fuel is much hotter and will burn old style alloy cases.

Additional information is also available from

If you want to know more about Jetex/Jet-x take a look at the Jetex Website This site gives information on how to get the best from Jetex/Jet-x as well as details of the availability of kits, plans and other Jetex associated items. Particularly note the Jetex/Jet-x postal event which Free Flight Supplies is one of the sponsors. In addition Free Flight Supplies provided support for the 50th Anniversary event.

There is also a site in the US run by Model Jet Plane which gives up to date information on Jetex/Jet-x activities in the US and further airfield. Currently a debate of fuel developments is taking place. A Mailing list is also available.

Visit "Megamodels", the manufacturers of Jet-x Website

If you want to know more visit the producers site for details see Rapier.  Jan Zigmund lists ideas that will help you get the best from the Rapier engine.

See the Product Review Page for further information.