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FTC Rockets and T-nozzle
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FTC and T-nozzle

On this page I will talk about our on going experiments with FTC rockets and T-nozzles. I might eventaully separate FTC rockets and T-nozzles into two pages. For now they will be on the same page. For those of you who are not farmilar with the meaning of FTC it stands for florecent tube covering. More commonly known as flourecent light bulb covers. They are extremely inexpensive and make great water rockets. We bought our supply at HomeDepot for about a buck a piece. That's the same price we pay for a soda bottle. FTC rockets are extremely aerodynamic, which makes them great for water rockets. Arodynamics is the one biggest factor in a water rockets performance.

My Firtst Rockets

Black Knight

Movies/galleries

This weekend we launched off our first FTC rocket. It was an interesting day. The first two launches the rocket backslid. On the third launch we tried using about a cup of water. The rocket slot off the launch pad like a bullet being fired from a gun barrel. It was a beautiful flight. The rocket went straight up. It began to backslide and then it came down nose first and stuck into the ground like a spear. The nose-cone was twisted like a medal frame work after a hurricane. I think that the rocket came down nose first because the center of gravity moves forward as the rocket accelerates. So when we used less water the rocket accelerated faster, so the center of gravity moved foward of the center of pressure and as a result the rocket came down nose first. We will have pictures of the twisted nose-cone soon.

This is a close up of the nose-cone.

Lawn dart
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Click on picture to enlarge

This is a picture of the nose-cone after the rocket came down nose first.

Lawn Dart clse-up of nose-cone
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click on picture to enlarge

After our first FTC rocket come down nose first, we built a new one. We saved the fins from our old rocket, because the fins are the most time consuming part of build a water rocket. We hoped that our new rocket would back-glide. We did not have time to run the center of area vs. center of gravity in the computer, but the center of graviy was far below the mid point, so we were willing to take the chance. We were also able to film some of the launches. To see a short clip, of a launch click on the link below.

click here to play video

I decided that if I was to continue to build Flourecent Lightbulb Covering (FTC) I would need to build another page. This page will also cover T-nozzles, and will have many pictures, since pictures are worth a thousand words. Below is a picture of the nose-cone assembly. The blue thing you see is a bottle cap from a wide necked soda bottle. The cap screws onto the neck of the same bottle, which we glued into the FTC with PL. The red thing you see is another FTC. The white thing is an Estes nose-cone. We wrapped clear scotch tape around the nose-cone to get a suction fit. We then friction fit the nose-cone with the red FTC, and then friction fit the nose-cone assembly with the blue bottle cap.

Noze-cone assembly
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Below is a picture of the fin assembly. We used PL premium (PL) to glue the fins to the rocket body. The fins are made from pieces of plastic. The quarters you see are wieghts that we added to make the the rocket backslide.

Fin assembly
dcp_0444_edited.jpg

Below are some pictures of our first T-nozzle design. Note the nozzle looks like a T.

T-nozzle loaded on the launcher
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Click on picture to enlrge

T-nozzle by itself
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Click on picture to enlarge

So what's so big about the T-nozzle. Well we wanted to get the initail burst off the launcher, but wanted a small nozzle once the rocket left the launcher. This is exactly what a T-nozzle does. As the rocket takes off the T-nozzle is picked off by the bottle neck and is held in by the pressure. This works because the the white PVC (which forms the top of the T) is larger than the bottle neck, and can not pass through. While the black PVC (which forms the stem of the T is slightly smaller and can pass through.