theplummeter

Members
 View Profile  See their activity

  • Content

    682

  • Joined

  • Last visited

  • Feedback

    0%

Posts posted by theplummeter

  3. Quote

    Quote

    So Shah, can we expect you will put your engineering genius to work on something similar?


    I'm a man!
    As such!
    We will need to go bigger!
    Yeah huge freaking wings! AND ROCKETS!

    But I think he's on to something amazing. The kids I introduce to engineering love watching his video.



    Be careful, you could end up inventing airplanes!

  5. The Genie line has one major problem that seems to have infected all of their lines in which one of the major printed circuit boards shorts and becomes unrepairable. It usually starts with not recognizing a remote and eventually disables the unit.

    There are three garage door installation businesses in town here (I've worked with them all as a new home construction subcontractor) and each of them have moved into the Liftmaster Chamberlain lines.

  6. Quote

    Quote

    I have two questions:

    Were you holding the leash when this occured?

    and

    Did her dog run within the radius of the leash if you were holding it at the time?



    Ummmm. I gots no dog in this fight... why you asking me?



    That was meant for the original poster

  8. I just sold two items, one on ebay and one through the classifieds here. The ebay item sold on the 8th, but the funds will not be available through paypal until the 26th. The payment from the classifieds on this site was instant. I don't understand the distinction, but it really is annoying since the ebay item arrived two days ago and the buyer is happy with it.

  10. I wouldn't want to be at the same level as a wooden prop if it separated either. It seems to me like a much better balance option would be to lift the ring up and mount the control box underneath.

    I also think a single powerplant (maybe a turbine) that turned all of the props either via belts or shafts would even out the power distribution, but I'm guessing a Chinese backyard experiment budget wouldn't cover one.

    Kudos to him though. He has obviously amassed some technical knowledge and combined it with imagination.

  11. Quote

    Ask him when you can go in airplanes also, both airliners and 'your buddies' light plane.



    This was a FAA physical, so in addition to the skydiving stuff I will have to get approval from a Senior Aviation Medical Examiner to return to work.

    I guess letting my sick days accrue without using one for the last twelve years might pay off.

  14. I'm not looking to do demos, really just trying to get a free canopy as we have a certain budget for PR spending and this would fall within that budget. I estimated 2k for a canopy with the logo, but as I have a brand new canopy already I also suggested a harness/container. I just have to get them quotes and they'll let me know a yes or no decision.

  15. ...and think I may have managed to hook myself up with a free logo canopy.

    At the conclusion of every work meeting when anyone asks if there is any new business I pipe up with rude comments about corporate sponsorship (or dirty jokes, or both). Today, we had a manager from the head office and I did my usual routine, but got the response that if I shoot him a reasonable quote on a logo canopy that he thinks he can make it happen.

    So, who would be the best folks to talk to and does anyone have canopy recommendations? I am currently jumping a Safire2 169 and absolutely love it, although I also loved the fusion and Sabre2. Would I contact the manufacturers directly or go through a dealer?

  16. Quote

    Quote

    i´ve a little question about the thick of the lines ?
    How i can calculate the required thick for my body ? :)



    That's called the line-thickness ratio, or LTR. What you do is take your exit weight, divide it by your canopy size in square feet, and then divide by 7, and that's how thick your lines should be. The "7" is known as the universal canopy line thickness coeeficient. Just tell your canopy manufacturer what your LTR number is, and they'll know what kind of lines to put on your canopy.


    Thank you for posting that. I just got done cutting the Vectran off my Safire and have 1000lb Dacron on order!

  21. Everything is fairly spot on except the bold statement. I don't know the exact number, but Garrett engines are several times more likely to suffer damage from a hot start than Pratts. Having to turn all of the mass of that engine from the back to the prop reduction gearbox requires a great deal more from the starter and battery.

    This is why Garretts start on stop locks in a flat pitch configuration and why some aircraft manufacturers (Commanders for example) have electical systems designed to run in either parallel or series mode to deliver more juice to the starter and keep things cooler.

    Quote

    here is an interesting (and seems balanced) point of view from an aviation forum. will need to dig up the link....

    Ahh yes...Pratt vs. Garrett (well, Honeywell now, but most people still call them Garretts) - one of the great debates of general aviation. I've seen several reasonable people resort to shouting at one another over this topic. Thing is, both these engines are so good at what they do that it really comes down to which characteristics are preferred by the aircraft operator.

    The Pratt is a very good engine - it's biggest advantages, in a nutshell, largely stem from it's unique design. Because the airflow reverses itself
    several times within the engine, it makes the gas generator and power sections into compact, self-contained units. This allows them to be broken
    apart for easy inspections and maintenance. Secondly, the design makes the PT6 a very smooth (there aren't any long driveshafts in the PT6), compact and lightweight engine when compared to it's competitors - a PT6A-135A (a new variant that is quickly becoming the standard install in many aircraft) weighs in at only 338 pounds (153 kg), yet produces 750 shaft horsepower. Finally, as mentioned above, the PT6 is, by nature of it's design, a very durable engine. It is not very susceptible to FOD ingestion (the air enters
    the engine at the far end and even then it makes a very tight turn from the duct to the inlet), and if the propeller were to strike the ground, the
    inspections and repairs would be substantially less expensive than comparable engines.

    However, the PT6 has a number of drawbacks. First of all, the PT6 doesn't respond quickly to power setting changes; all turbine engines have some lag
    as we know, but the PT6 has a LOT of lag, whereas the Garrett will respond virtually instantaneously to power changes. Secondly, the PT6 has a fuel
    burn penalty as mentioned above (it isn't huge - maybe a few percent overall), mostly due to the losses associated with turning the airflow
    through 720 degrees within the engine. Also, due to the long intake duct, the PT6 is very sensitive to intake icing - even small amounts of ice and
    frost can have dramatic effects on performance with this engine. As such, all PT6 installations I've ever seen continuously route some engine exhaust
    around the inlet lip for ice protection. Finally, the PT6 seems to be fairly susceptible to hot starts. Again, this has to do with the airflow reversing
    several times, which makes the job of cooling parts of the engine much more difficult under certain conditions.

    As for the Garrett, it's advantages lie mostly in the performance department. From a pilot's perspective, the Garrett is vastly superior - better power response, more fuel efficient and much easier to handle overall. However, the Garrett is not a particularly compact engine (especially in the high-power versions) when compared with the PT6, and
    maintenance is a royal pain in the ass on them. What's worse is that the Garrett sucks anything and everything into it's air inlet, which in turn attempts to make it's way through the gas generator - and as we all know, FOD can ruin a gas turbine engine. The Garrett also requires a huge amount of battery power to start - because the propeller is connected directly to the engine, you're spinning that on start as well, unlike the PT6 - so starting a Garrett without ground power can be a bit iffy if the aircraft has cold-soaked on a ramp at -30 all night. Finally, the Garrett is not a "good neighbour" engine - it's always running at 98% RPM (unless it's in ground fine - 70% or so), and as such it is tremendously noisy inside and outside the aircraft, making it unpleasant to work around (or in, for that matter) and unpleasant for people living near an airport or under the approaches to an airport.

    http://www.airliners.net/aviation-forums/tech_ops/read.main/260832/

  23. I ended up doing four sessions with Derek P. last week. He was an excellent coach and very laid back. Everyone at SVCO were wonderful and I learned a ton.

    I went in just to work on belly flying but after three sessions he ended up putting me on my back, which is a whole new discipline for me to suck at!

    Overall I couldn't be happier, just anxious to get in on some bigger group dives and try this stuff out.

  24. Lightning itself is a thunderstorm, even when the air producing it lacks precipitation. Thunderstorms are a hazard to airplanes for three main reasons:

    1. Tubulence. If the air is being tossed upward and downward in the same vicinity at a speed that rips electrons off of the passing atoms (lightning) then raining or not it's violent air movement

    2. Hail.

    3. Reduced or no visibility in heavy to extreme precipitation.

    Lightning might be a greater risk factor under a canopy than in an airplane, but if you're getting close enough for that to be a problem you'll probably already have your hands full.



    Quote

    Quote

    Quote

    Who is smart enough to answer my question ---

    A paraglider is flying in the vicinity of a developing stormcloud when lightning strikes in the distance. Is he/she in danger, not being close to the ground and simply a suspended object in the sky?



    Yes. Absolutely yes.

    It is foolish for anyone to be in the air and within five miles of a thunderstorm. Yes, aircraft occasionally do this, it's still not a good idea if at all avoidable.



    Let me refine my question ---

    I am not talking about anything else besides lightning. I understand the dynamics & dangers of thunderstorms.

    As far as I understand, a human in an open, flat field is more likely to get struck than any point in the field around him. This is because he presents the path of least resistance for the electrical charge.

    Now - my question as I intended but was not clear enough to state - is a human & fabric floating around in the air any more likely to get struck than any of the surrounding air? If so, why?