Recent content by Peter Twissell

Are you going to cast the cylinders in iron, or in aluminium with liners? Most of the Triumph twins used iron cylinders, but a few, including my 500, had aluminium with liners.

Ah, that's the 1963 to 1974 unit engine. Looking forward to seeing this....

Which variant are you building, unit or pre-unit? I have a pre-unit T100 from 1953. The T120 is the 650cc version of the T100. Your photo shows a unit engine with integral gearbox, but the "ghost" image shows a pre-unit engine. I'll be very interested to see how this project develops.

The device has no to rotational limit, but the readout goes from zero to 180 degrees, then counts back down to zero over the next 180 degrees. This is not a problem for me, as most of the parts I make are from my own drawings and I can draw parts with angles dimensioned to suit. You are welcome...

I've just been running some tests. At first, I thought something was wrong with the encoder or its installation. For the first 100 degrees or so of rotation, the readout aligned perfectly to the handwheel dial. Over the next few turns of the handwheel, the readings drifted apart until they were...

Hi Petertha, Thanks! The aluminium disc is part of the original device. It is attached to the PCB and houses the bearings which support the encoder rotor. An M3 screw through the rotor and bearings attached the rotor to the table spindle. The little peg is the end of the pushrod which operates...

This is the arrangement of the encoder PCB, mounted the my plastic disc and connected to the half of the original box which houses the display and batteries. The whole lot is sat on the aluminium base plate. The underside of the rotary table with aluminium plug, tapped M3 for mounting the...

That would be an alternative, but it's different to what I'm doing. I am using a cheap device to give me a direct readout of the angle of rotation of the table to an accuracy of approx 0.1 degrees, which is adequate for most purposes. The kit shown reads from an encoder on the worm, so it will...

Hi Timo, I am not using the pendulum. I have attached the encoder directly to the rotary table spindle, so there is no backlash and it will work in any orientation. The encoder and readout gives 0.1 degree increments. I will check the accuracy and repeatability against the scale on the...

I have one of the 6" rotary tables of generic design which can be mounted on edge as a dividing head. For various reasons, it would be advantageous for me to have a digital readout for the table angle. I had expected to find suitable kits readily available, as they are for linear readouts - but...

I have seen sliding valves on 'flame licker' engines, where atmospheric pressure holds the valve against the port face, while the cooling of the flame has in the cylinders creates a partial vacuum.

Each of these novel valve designs has it's own issues. Rotary valves work for steam engines (e.g. Corliss) but not so well for IC engines, where there are compromises in combustion chamber shape and gas flow. Sealing can also be a problem. Sleeve valves in IC engines have issues with heat...

Does that method give correct 'meshing' between the rotors? I have recently been modelling helical gears, using the sketch perpendicular to the helix method. For gears, this is correct as it represents the way the gears will be manufactured (by hobbing) and maintains the correct pressure angle...

Daniel, this is probably not the right place to get the feedback you are looking for. Most of us on this group are interested in building our own engines and are not likely to be buying ready built 'toy' engines. I would suggest looking for groups who collect Mamod, Wilesco and other...

Ah, but we also see that many of those sci-fi spaceships are somehow capable of taking off and landing from the surface of planets - the 'wings' presumably provide lift in atmospheres and double as radiators. Once we step into the realms of fantasy, we can justify anything...