Is there any literature on developing plans for a model from scratch?

I hit this problem yesterday changing a structure built on three columns to one with four. I use Solid Edge, which is quite good at changing structures at the assembly level, such that multiple sub-components change in concert (see this example), but I didn't expect SE to add extra holes and move existing ones as needed to accommodate another pillar.

What I actually did was copy the base, remove the three wrong column mounting holes, add four new holes in their revised locations, and then I rebuilt the assembly on the 4 column base using mostly existing parts. So I added the existing pillar component 4 times rather than 3. It was only necessary to redesign 3 components of about 20.

Though not fully automatic, SE made the change much easier to do than starting from scratch, and the original 3 pillar assembly is still available if I decide to go back.

Dave

I faced a similar problem at the start of my steam lorry project. Design in the main building blocks as far as you can on paper. Then make a full size cab area mock up in wood and junk. That allows you to sort out seating and get a stab at ergonomics. One observation is that controls like levers and pedals take up more space than you think thay will.

Rest of the design was done by overlaying the design on Fowler origial drawings, scanned to jpeg and scaled to model size.

Hope that helps,

Martin

Recall a merchant navy engineer who had visited a Royal Navy ship and said how much easier and faster maintenance was because they had built that into the engine room design

Merchant ships were built for the lowest dollar possible and to maximise cargo space

The other problem is the users are rarely the designers, there needs to be communication

A submarine chap who got onto a U-boat after WW2 wrote that the German boats were far better designed than the british subs as far as crew convenience was concerned

That would make German crews far better at their job for far longer, particularly since fatigue is a big factor when you are stuck in a smelly tin box for 2 or 3 months

Edited By Ady1 on 12/03/2023 14:07:00

Jelly, these just popped up on Youtube and I thought of you

Look closer into the history and it's apparent German and British submarine designers were working to significantly different requirements. British submarines and U-boats had distinctly different roles.

U-boats, at least the later variety, were designed to starve Britain into submission by stopping merchant vessels, to which they were steered by radio. This meant long-range, extended voyages, good fuel economy, first-class radio equipment, and deep diving to avoid the attention of the world's largest navy equipped with ASDIC. Although more attention was paid to crew comfort they were still dreadfully uncomfortable!

British submarines were primarily designed to blockade European ports; operating relatively short-range in shallow water, doing quick patrols, hardly ever using radio, operating against an enemy weak in anti-submarine facilities and only needing average fuel-economy. Less attention was paid to crew-comfort because patrols were expected to be much shorter.

Of course bad things happen when submarines optimised for one role have to take on another. U-boats were at a positive disadvantage in the shallow clear Mediterranean, where the smaller British U-class where far more effective. The British U-class wouldn't have performed well against Atlantic convoys. US submarines were designed to operate long patrols in the Pacific and paid the most attention to crew-comfort, possible because the boats could be bigger. They included air-conditioning, and were far more comfortable in hot climes than European and Japanese designs. Just as well they never had to operate in shallow waters where their size made them death-traps.

Curiously, the comfort thing was reversed in WW1 Battleships. Britain being a global power needed battleships with a long reach, meaning weight was allocated to fuel and comfort rather than armour plate. Germany had other needs: her battleships were intended to dominate the North Sea, so crew comfort took second place to engines and armour.

Jack Tar's opinion had little to do with it. Later, it was realised this was a mistake - the finest fighting machine in the world is hopeless when the crew are exhausted! The French Char B1 tank is an example. It's perceived role was incorrect, which led to a powerful vehicle with a tiny uncomfortable turret from which the commander was expected to evaluate the battlefield, decide tactics, direct the crew, co-operate with other units, and help work the guns. On paper, they were superior to German tanks, but they were used in uncoordinated penny packets and commanded by grossly overworked men. Failure to get the requirement right and ignoring human factors meant the machine couldn't deliver.

WW2 and after is full of examples of equipment being modified to increase efficiency by reducing wear and tear on the operators. However, even today crew-comfort is just one of many military design factors, and it's rarely the most important. For that reason designers try to reduce the need for humans in the system at all: though pilots hate the idea, there's much to be said in favour of pilotless aircraft.

Dave