Nerf blaster goes next-level with propane power

There are no shortage of Nerf gun mods out there. From simply upgrading springs to removing air restrictors, the temptation of one-upping your opponents in a Nerf war speaks to many!

Not content with such lowly modifications [Peter Sripol] decided that his blaster needed to see some propane action.

[Peter] completely stripped out the existing firing mechanism before creating a new combustion chamber from some soldered copper pipe. He added a propane tank and valve on some 3D-printed mounts, and replaced the barrel to produce some intense firepower.

To ignite the fuel inside the combustion chamber, some taser circuitry creates the voltage needed to jump the spark gap inside whilst an added switch behind the trigger kicks off the whole process. After experimenting with different ignition methods, [Peter] eventually found that positioning the spark in the center of the chamber provided the best solution for efficient combustion and non-deafening volume.

Though highly dependant on the amount of gas in the chamber during combustion, the speed of the dart was able to reach a maximum of 220 fps – that’s a whopping 150mph!

Next follows the obligatory sequence for all souped-up Nerf guns:  slow motion annihilation of various food items and beverage containers. To obtain some extra punch, some custom Nerf darts were 3D-printed, including one with a fearsome nail spear-head.

We strongly advise against taking up [Peter] on any offer of Nerf based warfare, but you can check out his insane plane adventures or last winter’s air sled.

Continue reading “Nerf blaster goes next-level with propane power”

Retrotechtacular: The J-57 Afterburner Engine

The J-57 afterburner engine appeared in many airplanes of notable make, including the F-101, -102, and -103. This USAF training film shows the parts of the J-57, explains the complex process by which the engine produces thrust, and describes some maintenance and troubleshooting procedures.

The name of this game is high performance. Precision thrust requires careful rigging of the engine’s fuel control linkage through a process called trimming. Here, the engine fuel control is adjusted with regard to several different RPM readings as prescribed in the manual.

One of the worst things that can happen to a J-57 is known as overtemping. This refers to high EGT, or exhaust gas temperature. If EGT is too high, the air-fuel ratio is not ideal. Troubleshooting a case of high EGT should begin with a check of the lines and the anti-icing valve. If the lines are good and the valve is closed, the instruments should be checked for accuracy. If they’re okay, then it’s time for a pre-trimming inspection.

In addition to EGT, engine performance is judged by RPM and PP7, the turbine discharge pressure. If RPM and PP7 are within spec and the EGT is still high, the engine must be pulled. It should be inspected for leaks and hot spots, and the seals should be examined thoroughly for cracks and burns. The cause for high EGT may be just one thing, or it could be several small problems. This film encourages the user to RTFM, which we think is great advice in general.

Continue reading “Retrotechtacular: The J-57 Afterburner Engine”

Retrotechtacular: The Diesel Story

The diesel engine was, like many things, born of necessity. The main engine types of the day—hot bulb oil, steam, coal gas, and gasoline—were not so thermally efficient or ideal for doing heavy-duty work like driving large-scale electrical generators.  But how did the diesel engine come about? Settle in and watch the 1952 documentary “The Diesel Story“, produced by Shell Oil.

The diesel engine is founded on the principle of internal combustion. Throughout the Industrial Age, technology was developing at breakneck pace. While steam power was a great boon to many burgeoning industries, engineers wanted to get away from using boilers. The atmospheric gas engine fit the bill, but it simply wasn’t powerful enough to replace the steam engine.

hot bulb oil engineBy 1877, [Nikolaus Otto] had completed work on his coal gas engine built on four-stroke theory. This was the first really useful internal combustion engine and the precursor of modern four-stroke engines. It was eventually adapted for transportation with gasoline fuel. In 1890, the hot bulb oil engine was developed under the name Hornsby-Akroyd and primarily used in stationary power plants. Their flywheels had to be started manually, but once the engine was going, the bulb that drove combustion required no further heating.

Continue reading “Retrotechtacular: The Diesel Story”