Getting Started.

This depends on where your interests lie and also where you live – there is nothing worse than building a model and finding that no-one else nearby flies anything similar. There is a list of local Flying Groups and contact details on the main website:-                 

 Just so you have an idea of what the indoor classes are all about then here’s a brief overview of the main classes that are flown in the UK, together with a guide as to what is involved in their construction and flying etc. L – Low, M – Medium, H – High.

Gyminnie Cricket (GC), unlimited rubber, see home page for plans etc.
Wood: L, Build: L, Covering: L, Rubber: L,M, Flying: L

The GC is available as a kit from Sky Hi models which makes a c9 gram model with a plastic propeller. This can then be later modified by you to give a 3 gm model with a reasonable duration performance. Most National competitions are for models conforming to this weight. It will take about 5 hours to build.

35cm Entry Level  1 gm airframe, no VP, unlimited rubber. Plans and building notes are available on the main website
Wood: L, Build: L, Covering: L, Rubber: L,M, Flying: L

The idea of this model is to provide a follow on from the GC to a recognised Class (F1R) but with an easy build, there are no rolled tubes, a sheet prop and no curved outlines to deal with. The model has a performance similar to an F1L, at the minimum weight of 1 gram, which can be achieved without too much difficulty. It complies with the competition rules for 35 cm but at this weight will obviously not compete with ultra light models. You can expect to achieve up to 10 minute flights in a 20’ Sports Hall. It takes about 10 hours to build.

Mini Stick 7” span
Wood: M, Build: L, Covering: L, Rubber: M, Flying: M

A fun little model, with a great performance. Small wood sizes a bit tricky and flying on high torque can resemble a 3D aerobatic performance. Quick build, about 5 hours.

F1L  International Class 1.2gm airframe weight, unlimited rubber
Wood: M,H, Build: L,M, Covering: L, Rubber: M,H, Flying: M

This is a long established class. Basically 18” wingspan with a maximum chord of 3”, this makes the wing rather long and thin and as a result needs care to make a stiff airframe. It is more of a challenge to achieve the 1.2 gm minimum weight than the 35cm Entry level model. Still quite quick to build at around 10 to 15 hours.

35cm (F1R) International Class, apart from minimum wingspan there are no rules!Wood:H, Build:H, Covering:M, Rubber: H, Flying: H


Bob Bailey has described this class as perhaps the most challenging as there is no minimum weight rule, currently sub 400 mg models hold the records! They are lovely models, even when built a little heavier they perform wonderfully well. They can match an F1D model’s duration. People like them because they hold their trim well due to having rolled balsa tubes for motor stick and tail boom. Not an easy build though due to small wood sizes.


Limited PennyPlane (LPP)3gm weight and no VP props! 
Wood: L, Build: L, Covering: L, Rubber: M, Flying: L

Much bigger wood sizes make it an easier build, no VP allowed so overall much easier to manage.

F1M – Similar to F1D but 3 gm minimum airframe weight.
Wood: L, Build: M, Covering:L, Rubber: M,H, Flying: M,H

Much bigger wood sizes make it an easier build but VP propeller takes it into a new level. Personally I find it a big model that has much the same level of difficulty as an F1D but not as pretty to fly.

F1D – THE International Duration Class. 1.4 gm airframe weight and 0.4 gm of rubber.
Wood: H, Build: H, Covering: M, Rubber: H, Flying: H

This is the class that is flown in the Indoor World Championships. Lovely models to build and fly but you do need some indoor building experience before giving one a try! Also a Variable Pitch propeller is a must, though the hubs are now available commercially – at around Euro80.

No Cal – A semi scale profile duration model
Wood: L, Build: L, Covering: L, Rubber: L, Flying: M

 Amazing little models.

Legal Eagle – A cabin duration model
Wood: L, Build: L, Covering: L, Rubber: L, Flying: M

See the Clayton Green website for details

Scale – Peanut, Pistachio, Open  
Wood: L, Build: M, Covering: M, Rubber: L,M, Flying: L, M

Very popular across the country, actually looked after by the Scale Technical Committee, but venues are often shared with the heavier Indoor Duration Classes.

Tony Hebb – ITC PRO