There are plenty of rocket experimenters toying with various liquid-fueled contraptions at the moment, and [Sciencish] is one of them. He grew tired of using air-pressurized fuel delivery systems in his experiments due to safety reasons, and decided to create something approximating more grown up rocket designs. The result was a 3D-printed turbopump for fuel delivery.
The design is not dissimilar from a turbocharger in a car. On one side, a turbine wheel is turned by compressed air supplied from a tank or compressor. This turbine wheel is affixed to the same axle as an impeller which draws up fuel and pumps it out, ideally into a rocket’s combustion chamber. It’s all made out of resin-printed parts, which made creating the fine geometry of the turbine and impeller a cinch.
Running on compressed air at 80 psi, the turbopump is able to deliver 1.36L of water or rubbing alcohol fuel a minute. However, unfortunately, this first pass design can only deliver 20 psi of fuel pressure, which [Sciencish] suspects will not be enough to counteract combustion chamber pressures in his rocket design. More work is required to up this figure. Paired with a nozzle and ignition source, though, and it does make for some great flames.
Overall though, the safety benefit of this turbopump comes from the fact that the fuel is kept separate from the oxidizer until it reaches the combustion chamber. This comes with far less chance of fire or explosion versus a system that stores fuel pressurized by air.
While the design isn’t yet up to scratch for rocket use, it nonetheless works, and we suspect with some improvement to tolerances and fin design that the project should move along at a quick pace.
Turbochargers as used on cars bear some similarities with jet engines. Fundamentally, both contain a turbine that harvests energy from hot gas, using it to spin a compressor which sucks in fresh air for combustion. Thus, turning a turbocharger into a jet engine is entirely possible, and [HRom] decided to have a crack at it.
The build starts with a turbo that appears to have been used on a diesel engine from the Volkswagen group. The first step was to cut the integral exhaust manifold off the turbo housing. A combustion chamber is then added which takes in fresh air from the compressor housing, and delivers hot combustion products to the turbine inlet. The homebrewed jet engine burns propane as fuel, introduced into the chamber via a nozzle.
The initial test failed as combustion was occurring at the turbine exhaust rather than in the combustion chamber, likely due to the lack of a proper ignition source inside the combustion chamber. A redesign employed a bigger combustion chamber built out of a fire extinguisher, with smouldering wood pellets inserted inside to get the injected propane burning.
The redesign works, and the turbocharger jet engine releases a thunderous scream as it turns at ever-increasing speed. However, with no oiling system or any way of controlling air or fuel flow in the engine, it eventually stops in a huge puff of smoke. Regardless, the engine did run in a sustained manner even if the ignition method was rudimentary.
We’ve seen similar builds before, and the rudimentary construction means they’re typically nowhere near being flight-weight engines. They are incredibly cool, however, and a great way to learn the basic principles of how jet engines work. Video after the break.
In prior centuries, it was common practice to tie the operation of a program to a computer’s clock speed. As computers got faster and faster, the programs tied to that slower clock speed sometimes had trouble running. To patch the issue temporarily, some computers in the early 90s included a “TURBO” button which actually slowed the computer’s clock speed down in order to help older software run without breaking in often unpredictable ways. [Ted Fried] decided that he would turn this idea on its head, though, by essentially building a TURBO button into the hardware of old computers which would greatly increase the execution speed of these computers without causing software mayhem.
To accomplish this, he is running CPU emulators on Teensys (Teensies?), but they are configured to be a drop-in replacement for the physical CPU of several retro computers such as the Apple II, VIC-20, and Commodore 64 rather than an emulator for an entire system. It can be configured to run either in cycle-accurate mode, making it essentially identical to the computer’s original hardware, or it can be placed into an accelerated mode to take advantage of the Teensy 4.1’s 800 MHz processor, which is orders of magnitude faster than the original hardware. This allows (most of) the original hardware to still be used while running programs at wildly faster speeds without needing to worry about any programming hiccups due to the increased clock speed.
The video below demonstrates [Ted]’s creation running in an Apple II but he has several other cores for other retro computers. It’s certainly a unique way to squeeze more computing power out of these antique machines. Some Apple II computers had a 4 MHz clock which seems incredibly slow by modern standards, so the 800 MHz Teensy would have been considered wizardry by the standards of the time, but believe it or not, it’s actually necessary to go the other direction for some applications and slow this computer down to a 1 MHz crawl.
If you want to coax more power out of your car’s engine, a turbocharger is a great way to go about it. Taking waste energy from the exhaust and using it to cram more air into the engine, they’re one of the best value ways to make big gains in horsepower.
However, unlike simpler mods like a bigger exhaust or a mild cam swap, a turbocharger install on a naturally aspirated, fuel-injected engine often requires a complete replacement of the engine management system, particularly on older cars. This isn’t cheap, leaving many to stick to turbocharging cars with factory tuneable ECUs, or to give up altogether. In the 1990s, aftermarket ECUs were even more expensive, leading many to avoid them altogether. Instead, enthusiasts used creative hacks to make their turbo builds a reality on the cheap, and there’s little stopping you from doing the very same today.
In 2014, Formula 1 switched away from V8 engines, electing instead to mandate all teams race with turbocharged V6 engines of 1.6 litres displacement, fitted with advanced energy recovery systems. The aim was to return Formula 1 to having some vague notion of relevance to modern road car technologies, with a strong focus on efficiency. This was achieved by mandating maximum fuel consumption for races, as well as placing a heavy emphasis on hybrid technology.
Since then, Mercedes have dominated the field in what is now known as the turbo-hybrid era. The German team has taken home every drivers and constructors championship since, often taking home the crown well before the season is over. Much has been made of the team’s engine as a key part of this dominance, widely considered to be more powerful and efficient than the competition at all but a few select races in the last seven years, and much of the credit goes to the company’s innovative split-turbo system. Today, we’ll explore why the innovation was such a game changer in Formula 1.
Old cars are great. For the nostalgia-obsessed like myself, getting into an old car is like sitting in a living, breathing representation of another time. They also happen to come with their fair share of problems. As the owner of two cars which are nearing their 30th birthdays, you start to face issues that you’d never encounter on a younger automobile. The worst offender of all is plastics. Whether in the interior or in the engine bay, after many years of exposure to the elements, parts become brittle and will crack, snap and shatter at the slightest provocation.
You also get stuck bolts. This was the initial cause of frustration with my Volvo 740 Turbo on a cold Sunday afternoon in May. As I tried in vain to free the fuel rail from its fittings, I tossed a spanner in frustration and I gave up any hope of completing, or indeed, starting the job that day. As I went to move the car back into the driveway, I quickly noticed a new problem. The accelerator was doing approximately nothing. Popping the hood, found the problem and shook my head in resignation. A Volvo 740 Turbo is fitted with a ball-jointed linkage which connects the accelerator cable to the throttle body itself. In my angst, the flying spanner had hit the throttle body and snapped the linkage’s plastic clips. It was at this point that I stormed off, cursing the car that has given me so much trouble over the past year.
Keeping with the automotive theme, a serve-motor-driven throttle from a Ford Mustang serves as a (naturally-aspirated) air intake, and a Honda Civic manifold delivers it to the grill. But when he really needs to turn up the heat, a 360 watt fan can force-feed the fire.