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  1. #1
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    Anyone want to power a helicopter and set a world record?

    Prize money is at stake.

    I'm searching for someone near central Texas who has a high power to weight ratio. A 135 pound pilot would have to output 600 watts for 60 seconds. I can change the design to require 500 watts, but there would be other problems. For every 20 pounds heavier you are, your power to weight ratio must be 5% higher. For every 20 pounds lighter you are, your watts/Kg can be 5% less. So a very light pilot would perform better if in equally good shape. I'm looking for someone who rides up steep hills fast, not someone who sprints fast on level ground. I read that professionals can output more than that.

    I'd rather do this myself for insurance reasons, but currently can output 500 watts for only 20 seconds, and 350 watts for 60 seconds. I weight 147 pounds, but can probably lose at least 5 pounds of fat. I've done plenty of 5k running in high school and 11 mile rushed bike rides to work after high school, but have been less active the last 2 years. Think I can reach my goal in 3-4 months?

    It won't be a real helicopter. It will look more like this:
    http://www.humanpoweredhelicopters.org/yuri1/index.htm
    The current record is 2 feet off the ground and 19 seconds (no prize for them). We need 60 seconds, and temporarily exceeding 10 feet off the ground, to win.

    I'm a backyard inventor with some college engineering behind me. I plan to have this built by February or so. I'm doing small scale tests, but the main safety test will be me flying it for 20 seconds while you watch. If I don't crash, then you fly it for 60 seconds. Most engineers say getting 10 feet off the ground will be impossible, but I disagree.

    Please hop on a gym bike, put it on a high resistance level, rev it up to a high rpm, and let me know what watts you can output for 60 seconds. Or tell me the calorie reading and I'll convert it. You want at least 33 calories in 60 seconds.

    Also be warned that since I still have not found insurance, the whole project might get scrapped later. I just want someone lined up in case I do get insurance and am unable to output that power long enough.
    Last edited by AaronTX; 10-23-10 at 07:44 PM.

  2. #2
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    I'm interested...

  3. #3
    ride lots be safe Creakyknees's Avatar
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    try posting on TXBRA.org, lots of racers hang out there.
    "have fun and be kind"
    - an internet post

  4. #4
    Cycle Dallas MMACH 5's Avatar
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    I weigh about 150 and don't have that kind of power, but please keep us posted on how this goes. It sounds fascinating.
    That's gonna leave a mark.

  5. #5
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    Quote Originally Posted by hrt4me View Post
    I'm interested...
    How much do you weigh, and how much power can you output for 60 seconds? What rpm allows you to do this?
    Please do not attempt to test yourself with one of those meters on level ground. The speed you reach would be dangerous. A hill would be safer, or the gym. I haven't yet built this, but I have to build it for the weight of the pilot. There is lee way, but a 140 pound pilot would need a different helicopter than a 130 pound pilot.
     
    Quote Originally Posted by Creakyknees View Post
    try posting on TXBRA.org, lots of racers hang out there.
    Thank you for the tip. I will.
     
    Quote Originally Posted by MMACH 5 View Post
    I weigh about 150 and don't have that kind of power, but please keep us posted on how this goes. It sounds fascinating.
    Probably 1% of cyclists have that power to weight ratio. Maybe less than 1%. But lucky for me I don't need a world class athlete to output that much. I just need a very fit competitive cyclist, not even a professional. The weight range I'm looking for will eliminate just as many candidates.

  6. #6
    Senior Member dougmc's Avatar
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    Quote Originally Posted by AaronTX View Post
    Or tell me the calorie reading and I'll convert it.
    Just how would you do this conversion? (I'm skeptical that you really can, as calorie readings seem to be a wild ass guess at best.)

    The exercise bike at work says I do about 400 calories in 30 minutes. Doing the math, that's an average of 953 watts -- uh-huh. You must be doing something other than this. (It also thinks I average 21 mph, though my real world values are closer to 16 mph -- I'm certainly not who you're looking for.)

    In any event, interesting project ...

    EDIT: hmm, I guess if I consider that human muscles are about 20% efficient, 953 watts becomes 191 watts -- which is still on the high side, but it's in the ballpark, especially once I consider that a certain amount of energy goes to just keeping me alive.
    Last edited by dougmc; 10-09-10 at 02:00 PM.

  7. #7
    Born on a Bike ik04's Avatar
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    Howdy,

    Where in Central Texas do you plan to work on this project? I am a professional helicopter pilot and I have a 135 pound, 17 year old son who might meet the power output criteria.

    I'm interested to see how you plan to fly for 60 seconds and the overall concept of your design.

    welcome aboard!

  8. #8
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    Quote Originally Posted by dougmc View Post
    Just how would you do this conversion? (I'm skeptical that you really can, as calorie readings seem to be a wild ass guess at best.)

    The exercise bike at work says I do about 400 calories in 30 minutes. Doing the math, that's an average of 953 watts -- uh-huh. You must be doing something other than this. (It also thinks I average 21 mph, though my real world values are closer to 16 mph -- I'm certainly not who you're looking for.)

    In any event, interesting project ...

    EDIT: hmm, I guess if I consider that human muscles are about 20% efficient, 953 watts becomes 191 watts -- which is still on the high side, but it's in the ballpark, especially once I consider that a certain amount of energy goes to just keeping me alive.
    Calories are a unit of energy, whereas Watts are a measure of energy per second.
    Upright bikes assume that only 23% of the energy your body burns is put to useful work.
    I think some recumbant bikes assume 50% of your energy is put to useful work. The bike measures the work performed, and divides it by that percentage to get calories burned.

    Yes, it is not a good estimate of the actual calories burned. But as long as we know the ratio the bike uses (probably 23% for upright and 50% for recumbant), we can accurately measure the power, but not the actual fat loss.

    As for your 800 watts, it probably is 200 watts. Your 60 second power should be about twice that, though the ratio differs from person to person.

    Your speed in real life is a measure of your power to wind resistance ratio. Lighter people have more surface area compared to their volume and power, and will be left behind on flat ground by big people. And if you did those watts on a recumbant gym bike, it might be closer to 400 watts. And that is your 30 minute power. You need to give it everything you've got for 60 seconds and then let me know. I'm sure you can perform better for just 60 seconds than you can for 30 minutes.
    Last edited by AaronTX; 10-09-10 at 07:22 PM.

  9. #9
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    Quote Originally Posted by ik04 View Post
    Howdy,

    Where in Central Texas do you plan to work on this project? I am a professional helicopter pilot and I have a 135 pound, 17 year old son who might meet the power output criteria.

    I'm interested to see how you plan to fly for 60 seconds and the overall concept of your design.

    welcome aboard!
    I was planning to get a recent high school grad just because they are lighter, but they probably have to be 18 in order to concent to taking the risk of something going wrong.

    My design will have 4 props like the yuri, but be a lot lighter, a bit bigger, and have other improvements. You would definitely be able to see it before your son rides it. I just don't want to post it here long before I have it built, and risk someone else googling this and building it.

    The Yuri propeller is optimized to sweep the floor, since its blades have no twist. Mine will have twist, like an airscrew, so it will be more efficient higher above the ground. There is a lot more to it than that. I can't say too much though.

  10. #10
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    I updated the power requirements. See the edited first post. You can be any weight as long as you match the power for that weight. For every twenty pounds more than 135, your power to weight ratio must be 5% higher than 10 W/Kg. And for every 20 pounds less than 135, your power to weight ratio can be 5% lower than 10 W/Kg.

    I can build the helicopter to require less power than that, but I'd have to build it bigger, which would cost more, and would mean it would have less room between the tips and anything it might crash into. So I'd prefer to find a good athlete before re-designing it.

    Your power output should be higher in the first 30 seconds than in the second 30 seconds, since you do have to climb. But it should still be somewhat flat, since you still need a certain power output to stay in the air at the very end. I just know the power needed to for a constant hover. I'll have to go figure out the power needed to climb or descend. It should not take long to figure it out.

  11. #11
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    I posted on txbra, and got a few responses, but then my post got deleted. I could try again.

    As for this site, I'm wondering if there just are not many TX cyclists browsing this, or not enough ultra athletes, or if cyclists just are not interested. And if they are not interested, then why?

    One cyclist from this forum is interested, though his power to weight is borderline.

    I could build this bigger, but it would cost more and would be harder to transport and fit anywhere flat.





    Well, after doing an estimate of how long it will take to build all the many parts, looks like it may be a year or two. But nothing wrong with getting people lined up sooner than later. It gives you more time to train.
    Last edited by AaronTX; 11-15-10 at 09:42 PM.

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