The Ship Model Forum

Fliger747 wrote:Quite the aerial view of the ship! A tall ladder? Most spectacular ship with the lighting and all!

Best regards! Tom

Goodwood wrote:Song, if you ever get the chance to show this bad boy off to a U.S. Navy sailor, I can imagine they'd be quite taken with your work. Especially one who'd served aboard a Nimitz-class CVN.

It certainly continues to blow my mind!

DrPR wrote:With all the lights you have put into this model it will generate quite a bit of heat. Good to see in your last photo that you have a fire extinguisher handy!

Seriously, how much power (voltage * current) will it draw when it is full on?

Phil

DrPR wrote:70 Watts isn't too much heat, but you need to take it into account. The power supply itself will also generate about as much heat (they aren't 100% efficient).

That much heat inside a closed space will cause a pretty good heat build up. I have done heat analysis for electronics packaging and it is often necessary to provide a fan to generate constant air flow to carry away the heat. Convection may not generate enough air flow to remove the heat.

Plastics have a large coefficient of thermal expansion, so it doesn't take much heat to cause warping. You can find the numbers for the type of plastic you are using on the internet. I think I recall that a 5 meter sheet of acrylic will lengthen 5 mm with a 20 degree Celsius temperature rise. So a 2 meter flight deck could grow 1-2 mm with a 10-20 C temperature rise. If the rest of the ship isn't heating equally the different expansion rates may cause things to break apart.

The gray flight deck will be a good radiator, and it has a large surface. So it will be relatively cool on top. But the plastic under it inside the hangers will be much warmer. And if the model is sitting in direct sunlight the flight deck will absorb a lot more heat, causing it to expand further.

When you get the ship assembled watch the temperatures inside and outside carefully when the lights are all on. If the flight deck gets warm to the touch it will be much warmer inside the hanger deck. You may need to put a small fan inside the hanger deck to circulate air.

Phil

Fliger747 wrote:Include a temperature limit switch? Certainly the lights would be on intermittent duty.

Clever and spectacular setup!

Regards: Tom

Fliger747 wrote:Song:

This is even more impressive with the hull paint and the props/rudders. Do you have an assistant to help turn this very large model over for the bottom hull work? I especially like the way the rudder and associated skeg fit together!

Best regards! Tom

DrPR wrote:Song,

Heat may not be a problem so I wouldn't worry about it until you run a few tests. But I would make provisions for a small fan somewhere on the hanger deck where it will not be visible from outside. If the internal temperature rises 10 degrees Celsius take notice! If it rises 20 degrees Celsius you WILL have problems!

I know of two R/C aircraft carrier builds (1:72) where some plastic parts buckled in the heat when exposed to direct sunlight. This required significant rebuilds. My own experience was with a 1:96 fiberglass Cleveland class hull with extensive Plexiglass internal framing. While reshaping the hull outside with Bondo, using the sun's heat to cure the body filler, the plexiglass parts expanded much faster than the fiberglass and the force was great enough that some well-cured epoxy bonds broke, allowing some longitudinals to break loose. It was a hard learned lesson, and when I build the superstructure I will include the expansion joints the real ship had!
Dear Phil!
I very thank your experience of R/C ships. The theory of expention from heat too.
I consider it my model.
Thank you again.
Song
Phil

mikegr wrote:What a massive built!