Tailwheel types

[Thruster87]

The few thrusters that I've seen all had different tailwheel setups. They ranged from shopping cart trolley wheels to pneumatic chrome moly tubing home made jobs. Tony what is an acceptable standard or updated/modified version of the type/weight tailwheel assembly which in your opinnion may be used.

 

Cheers Alan

 

 

[Guest TOSGcentral]

Damn! That is a bit like asking how long is a piece of string J

 

To make sense of any answer we best go to five categories of the 55 plus Thruster types.

 

However, I should first say that a pneumatic tailwheel will assist any Thruster via reducing back end wear from vertical shocking – but will increase shear load stressing (from the larger diameter wheel) on some types when the machine is turned on the ground.

 

Generally Thrusters were equipped with the ‘shopping trolley’ set up (in various diameters) and anything similar will do. The pneumatics are authorised on 95.25 types – but I think we can do a bit better than the factory modification that looked as though it had come of a four engined WW2 bomber – it was that big!

 

1. Early Thrusters. These do not take kindly to the pneumatics as they have a bungy springing system on what is a quite flexible ‘swinging arm’. These do not tolerate much turning forces and the wheel lays over. This is acceptable in a private machine where you know what is going on and operate it accordingly. But is no use on an aircraft that a number of people have access to. A Glasshouse C is currently fitted with one of these and although the wheel does great things in shock absorption, reasonable care has to be taken in turning on the ground and some effort went into getting the geometry right.

 

2. 95.10 types. These are mainly the factory production single seaters and all were originally fitted with bungy sprung tailwheel assemblies. Some have been retrofitted with a sprung steel tailwheel mount but that is not wise due to the light alloy ventral fin it is attached to which would then need beefing up. Bit like eating nuts – once you start it is difficult to stop!

 

3. 19 Series types. There are not many of these, they are all in TOSG’s care and are ultra historical preservation machines. They are all equipped with a variety of tailwheels that work correctly.

 

4. 95.25s. These originally came out with a commercial solid rubber tyred effort with a plastic hub. They are no longer available. While the original does the job and wears well, replacements could be virtually anything I suppose (based on who will notice!). They can be modified legally to pneumatics and in my opinion this should be done. A larger fork assembly has to be made and a double tailwheel spring is advisable, if not mandatory! These give far enhanced back end cushioning and vastly improved steering.

 

Weight & Balance. If fitting a pneumatic tailwheel assembly then the machine should be re-weighed. It may not seem a lot of weight in you hand but it is on a long moment arm from the C of P and could make any individual aircraft tail heavy in flight – so please check that!

 

Does that answer your question?

 

Aye

 

Tony

 

 

[Thruster87]

Just. The part about the double spring, are there any drawings or spec's for this setup and does anyone sell them or is it a custom job.As I'm rebuilding my TST I'm keen to do all the mods or updates as possible [which my funds allow]

 

Cheers Alan

 

 

[Guest TOSGcentral]

No, unfortunately there are not! However it is not a huge technical exercise in practical terms.

 

You simply want a second spring about 2/3rds the length of the main spring, suitably bent at one end before tempering, and slightly curved up at the the other end to reduce localised pressure.

 

Keepers are seldom used but a hose clamp would suffice to keep alignment.

 

Sorry this does not sound very posh and technical - but then you should see some of the challenges on my desk at the moment and some of them are a tad hair raising!

 

Aye

 

Tony