Skip to main content

Teaching model

More
4 years 9 months ago #203467 by grandad
Teaching model was created by grandad
This is a vintage teaching model showing the operation of a mechanical braking system on a drawbar trailer
The following user(s) said Thank You: BillyP, dno, PaulFH, Southbound, werkhorse

Please Log in to join the conversation.

More
4 years 9 months ago #203468 by grandad
Replied by grandad on topic Teaching model
The following user(s) said Thank You: BillyP, cobbadog, dno, Lang, Mrsmackpaul, PaulFH, Southbound, werkhorse, xspanrman

Please Log in to join the conversation.

More
4 years 9 months ago #203471 by Morris
Replied by Morris on topic Teaching model
Grandad,
that is a great historical model and definitely worth keeping and displaying at shows.

I have my shoulder to the wheel,
my nose to the grindstone,
I've put my best foot forward,
I've put my back into it,
I'm gritting my teeth,

Now I find I can't do any work in this position!

Please Log in to join the conversation.

More
4 years 9 months ago - 4 years 9 months ago #203482 by Lang
Replied by Lang on topic Teaching model
Grandad

What a good subject! Big difference between hearing and seeing when you are trying to learn something. Here are a few more.

Lang
Last edit: 4 years 9 months ago by Lang.
The following user(s) said Thank You: BillyP, cobbadog, Mrsmackpaul, PaulFH, Southbound, werkhorse

Please Log in to join the conversation.

More
4 years 9 months ago - 4 years 9 months ago #203485 by grandad
Replied by grandad on topic Teaching model
A bit more on the trailer-
If the trailer becomes detached from the towing truck the safety chain lifts this catch to allow the spring inside the tube to put the brakes on.
The wheels and brake drums have slots in to be able to see how the brakes work
Last edit: 4 years 9 months ago by grandad.
The following user(s) said Thank You: Bobsboy, BillyP, cobbadog, Lang, Mrsmackpaul, PaulFH, werkhorse

Please Log in to join the conversation.

More
4 years 9 months ago - 4 years 9 months ago #203487 by grandad
Replied by grandad on topic Teaching model
Morris, I get a lot of interest at shows with these models and it's surprising how many youngsters like to know about them too.
I can put up some more pics of them if you like
Last edit: 4 years 9 months ago by grandad.
The following user(s) said Thank You: Sarge, BillyP, cobbadog, Morris, wee-allis, werkhorse

Please Log in to join the conversation.

More
4 years 9 months ago #203498 by Mrsmackpaul
Replied by Mrsmackpaul on topic Teaching model
Very well built models
To see and feel and push and pull etc is a great way to learn things

A lot different than watching a iPhone app

Grear stuff grandad and please keep on sharing, I find this stuff very interesting

Paul

Your better to die trying than live on your knees begging

Please Log in to join the conversation.

More
4 years 9 months ago #203534 by Bobsboy
Replied by Bobsboy on topic Teaching model
Ya,

Even for those among us that already know everything there is to know, can have a bit of a play, a push and a prod and (quietly, silently) finally, after all these years actually Understand how it all works (true knowledge).

Thank you to all those model makers tinkering away in their mini toolmakers man cave workshops.

-b

Mucking about on the edge
The following user(s) said Thank You: cobbadog

Please Log in to join the conversation.

More
4 years 9 months ago #203571 by grandad
Replied by grandad on topic Teaching model
Another model, this one shows the workings of a four stroke engine

Ignition too!

Interesting throttle
The following user(s) said Thank You: BillyP, cobbadog, Lang, PaulFH

Please Log in to join the conversation.

More
4 years 9 months ago - 4 years 9 months ago #203572 by Lang
Replied by Lang on topic Teaching model
Here is something a bit more modern Pratt and Whitney PT6 Turboprop.

It needs the explanatory drawing for those not in the game. The air comes in the back of the engine (blue) and and is seriously compressed by the axial and radial compressor blades. It runs forward and fuel is ignited in the combustion chamber just before the compressor turbine. This creates huge pressure which A. keeps the cold air section turning via the shaft from the compressor turbine This makes the action totally self sustaining until the fuel is cut off. B. Expands forward through the power turbine blades which drive the geabox and prop.

Turbine engines are controlled solely by a fuel "tap". The more fuel you put in, the bigger the fire behind the compressor turbine, the bigger the expansion and the greater the power. The pilot is restricted either by temperature (too much fuel and blades start to melt) or torque which if too great will start to break things in the gearbox. The two gauges are watched closely on take-off or climb and according to whether it is a hot or cold day when one reaches the red line you can not push the throttle any further.


Interesting thing about these free turbines is there is no mechanical connection between the jet engine power section and the drive to the gearbox. It is just two turbines facing each other. Just like putting two house fans together, switch only one on and the airflow will soon have the other turning at the same rate as the powered one. It is easiest to see when a turbine helicopter starts up. You can hear the engine whining at full speed while the blades slowly catch up until they are "locked" to the engine speed by the compressor and power turbines coming in to synchronization. Many automatic transmissions operate on the same system but with fluid instead of gas.

Last edit: 4 years 9 months ago by Lang.
The following user(s) said Thank You: BillyP, PaulFH

Please Log in to join the conversation.

Time to create page: 0.582 seconds