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Elijah

Member Since: January 12, 2011

Country: United States

Profile

Spoken Languages

English

Programming Languages

C, C++, PHP, Perl, BASIC

Associations

IEEE

Universities

Embry Riddle Aeronautical Univ

Expertise

Embedded systems

Interests

RF comm, general electronics, RC airplanes, IP Networks, High Altitude Ballooning

Websites

http://ad7zj.net

  • The ignitor should be running before fuel is turned on. Listen to any turbo prop start up and you’ll hear the ignitiors snapping as soon as the starter kicks on. Fuel is not turned on until the engine is at the right speed and then ignites almost immediately under normal circumstances.

  • Awesome project, I’ve always wanted to do something like this too :-) Sorry if I missed something but I didn’t see you mention the fuel flow control which is very critical. Based on my experience with model aircraft turbines, pretty much everything is controlled by the amount of fuel being pumped into the engine - that’s your throttle and mixture control. Getting the mixture right is key to both starting (without the hot start) and throttling without it flaming out. Ie you can’t just turn the fuel on full as the starter spools it up and expect it to light. Ultimately you probably need a control loop based on the EGT and RPM but I bet if you set up a manual control that allows adjustment for the fuel flow you’ll get it to light just by experimenting. I’m curious how the fuel flow is controlled mechanically. Maybe varying the pump speed? That’s how the model turbines do it…

    Some model turbines do start on propane/butane and then switch to Jet A, but I think that has more to do with them igniting the fuel with a glow plug whereas you have a really hot spark. I think if you get the mixture right it’ll light right off. I would stick with running it on jet fuel, simpler than trying to switch from propane and a typical BBQ propane regulator will never feed it enough gas to actually spool up.

  • Yeah sorry, I think adafruit’s $10 markup (that’s ~30%) is ridiculous. That is so at odds with Raspberry pi foundation’s goal of keeping the costs down. Probably because raspberry pi is so popular, resellers like to get as big a cut as they can. But as others have said, it’s a free market - buy them from MCM or here instead :-)

  • Yay, more gov regulations that favor over-seas companies (who do not comply with the rules and have little to lose) instead of domestic companies like SparkFun (who follow the rules and have everything to lose). At least TSA makes me feel safe </sarcasm>.

  • It’s hardly surprising seeing this from Barbie. Through and through, down to its roots barbie is all about the stereotypical, shallow feminine behaviors: being sexy, glamorous, fads, fashion, and appearance. As Susan so eloquently states in her oft-quoted “Girls and Software” essay, the course of events that deter girls from technical fields is set at an early age. It is not just a problem with this edition of a Barbie book, it is a problem with Barbie as a whole. And until our culture is willing to dump the entire “Barbie” mentality, all the affirmative action programs in education and the workplace will do little to help.

  • Famous last words: “What you lack in propeller, make up for in elevator”

  • Well said. And I will agree 100%, the ‘brogrammer’ culture needs to fall off a cliff and die. Diversity is good in all sorts of ways, hardly anyone would disagree with that. The problem with these affirmative-action type programs is they distort the picture the other way and only exacerbate the underlying problem (which as mentioned is subtle behaviors which turn women off, and I guarantee that a playing field tipped towards an individual just for being female will only encourage these subtle behaviors). The reality is, women have different interests and all biases and prejudice aside, there will NEVER be an equal number of women in tech for the same reason there will never be an equal number of men in the child care or health care industry. Our culture seems to be of the mindset that everyone is equal, therefore they are the same; equal yes, but the same? Not really.

    I applaud efforts to make a workplace that is friendly towards women. I do not applaud the efforts to go out of ones way to give women more opportunities just for the sake of being women.

  • Anyone flown this on a high altitude balloon yet, or have confirmation it works over 60K ft?

  • There have been been lots of successful land vehicles using (far bigger) gas turbines, it’s definitely what I’d use it for.

  • That would take all the fun out of it!

No public wish lists :(