# Recent content by matt621

1. ### I Making a heat shield for my car's exhaust

To berkeman: I'm adding an aux. fuel tank and lines to an existing vehicle. I also have a race car (with turbo) that is fabbed. So this issues comes up more than once. :-) To Baluncore: Yes, thanks. My thought was to make one side of the heat shield more like a black body and the other side a...

3. ### I Making a heat shield for my car's exhaust

Hello, I'm just wanting to make sure I remember this correctly. I have a hot exhaust pipe I want to shield from fuel lines. So I have a shield (stainless) that is going 1/2 way around the exhaust, with an air gap of about 1". I want to sand blast the side facing the heat and polish the side...
4. ### I Calculating the windspeed based on a brick being launched off of a closed dumpster lid

I think it's safe to assume the brick did not slide down much once the lid started to rise up. Even just a little opening would cause the lid to flip nearly instantly. So the starting height above ground would be about 5'. So what I did was use a cannon ball trajectory and if I select a launch...
5. ### I Calculating the windspeed based on a brick being launched off of a closed dumpster lid

Hello, We had a wind storm. We have a dumpster with a lid. On that lid we put a heavy brick to keep the lid closed during wind storms. It's worked great for years. But we had a very strong wind storm and it launched that brick quite a distance. I'm trying to figure out the wind speed that would...
6. ### Calculating Temperature Change for Heat Exchanger

I'm sorry, I'm unable to provide a sketch. If you just imagine 2 plates parallel to each other, about 1/8" apart forming a channel for the air to go thru. (ends blocked so it creates a long thin tunnel for the air to pass.) The blocks will be kept at approx. 32F (or lower). Based on the speed...
7. ### News NYTimes: [Scientific] Fraud Scandals Sap China’s Dream...

My point is from the perspective of the Chinese Govt, not the HK residents. They found the golden goose and all they did was changed who owned the goose not how the goose did it's work.
8. ### If maths was a food, which food would it be?

Oh come on! If Math was food there is only one real answer: Chocolate! Nothing so bitter could taste so sweet with just a little imagination.
9. ### News NYTimes: [Scientific] Fraud Scandals Sap China’s Dream...

The main reason China is anything at all is Hong Kong. Look at the history of the Chinese economy and exports. There is Pre-HK and Post HK. When the Chinese took over HK from the British at the end of the 99 year lease, they saw how well it worked and said, "if it ain't broke, don't fix it."...
10. ### Do people become less self-conscious as they get old?

This is easy to illustrate why. There are lots of websites selling a chart. It's called "the number of weeks of your life." You print it out and you find our current age and mark all the weeks before that off. As you get older you realize the number of weeks you have left is getting smaller and...
11. ### Negative pressure in house after winterizing

My opinion: Everything in the house creates heat. People, stove, water boiler, oven, TV, etc. That has to go someplace. So it's found a way out. Chimney, holes for the lights, wall outlets, door jams etc. That creates a current of air that is creating an negative (with relation to outside)...
12. ### Calculating Temperature Change for Heat Exchanger

Hello, After the last post I completely changed the system. I now have a new system. Based on the feedback from last time I increased the time in contact with the block significantly. And I have made it a two stage unit. Here are the parameters for the first stage. An Aluminum block...
13. ### Need help with wiring motors in series and in parallel

Yes, the the gearbox. The mount for the motor/pinion is not in the correct location. The pinion to first gear is binding, has zero backlash. It was so bad it wore down the center hub of 2nd gear (the pinion was pushing on first gear so hard it transferred the force to 2nd gear. First gear has a...
14. ### Need help with wiring motors in series and in parallel

No bad smell. I'm going to put a fan in there to exhaust the hot air anyway. also see if I canfind a heat sink to fit them. they are popular with the RC folks so it should be possible. thanks
15. ### Need help with wiring motors in series and in parallel

Yes, I got a msg from the seller. They believe one of the gears is binding on the axle. I will pull the "gearbox" apart and check to see that the gear is spinning freely. I just hope it didn't gall the shaft from our test runs. Thanks. (I put "gearbox" in quotes because I can't with a straight...