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Old 26th January 2013, 05:41 PM   #201
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Video of the Atlas Team's 30 second, five feet flight - http://www.youtube.com/watch?v=hm8Lv...ature=youtu.be

Some more info here - http://www.aerovelo.com/2013/01/26/p...ng-very-close/

Would like to see video of the failed prize attempt flight.

Is anyone else still interested or am I just talking to myself here?
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Old 26th January 2013, 06:10 PM   #202
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*Definitely* interested. I keep thinking of ways to do it myself. Hehe. But not being an engineer, I don't have a realistic dog in this fight. My participation is theoretical. My interest in this challenge is not.
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Old 26th January 2013, 07:35 PM   #203
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Originally Posted by ynot View Post
Video of the Atlas Team's 30 second, five feet flight - http://www.youtube.com/watch?v=hm8Lv...ature=youtu.be

Some more info here - http://www.aerovelo.com/2013/01/26/p...ng-very-close/

Would like to see video of the failed prize attempt flight.

Is anyone else still interested or am I just talking to myself here?
Two things strike me about this flight. First is that their design is not able to absorb the full power of their pilot, for the reasons they stated, and the second is that they are not using an optimal power plant. I wonder what someone could do with a world class climber or sprinter at the pedals coupled with a machine that could take the power.
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Old 26th January 2013, 08:27 PM   #204
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Originally Posted by ynot View Post
Video of the Atlas Team's 30 second, five feet flight - http://www.youtube.com/watch?v=hm8Lv...ature=youtu.be

Some more info here - http://www.aerovelo.com/2013/01/26/p...ng-very-close/

Wow, that thing is huge. It took me a while to visually parse the photograph; things that I thought at first were parts of the building are actually parts of the vehicle, and vice versa. Interesting that they went with a giant quadrotor. That pyramid of long support trusses must have a high cost in weight and power distribution issues, so the design must have some really big upsides to be worth it.

Quote:
Is anyone else still interested or am I just talking to myself here?

Interested.

Respectfully,
Myriad
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Old 26th January 2013, 08:33 PM   #205
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Originally Posted by Mister Earl View Post
*Definitely* interested. I keep thinking of ways to do it myself. Hehe. But not being an engineer, I don't have a realistic dog in this fight. My participation is theoretical. My interest in this challenge is not.
Great - I'll keep rambling on then.
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Old 26th January 2013, 08:39 PM   #206
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Originally Posted by Marcus View Post
Two things strike me about this flight. First is that their design is not able to absorb the full power of their pilot, for the reasons they stated, and the second is that they are not using an optimal power plant. I wonder what someone could do with a world class climber or sprinter at the pedals coupled with a machine that could take the power.
Even before their prize attempt I thought it was maybe more to do with publicity for fundraising purposes rather than a serious attempt at winning. If nothing else the Atlas Team are by far the best at fundraising. I don't see 30 secs and 5 ft as being as "close" as they claim. Gamera have done better and I don't think even they can claim to be "close".
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Old 26th January 2013, 08:43 PM   #207
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Originally Posted by Myriad View Post
Wow, that thing is huge. It took me a while to visually parse the photograph; things that I thought at first were parts of the building are actually parts of the vehicle, and vice versa. Interesting that they went with a giant quadrotor. That pyramid of long support trusses must have a high cost in weight and power distribution issues, so the design must have some really big upsides to be worth it.
Very similar design to the more successful Gamera - http://www.agrc.umd.edu/gamera/index.html
Both are copies if the earlier (1994) Yuri - http://www.youtube.com/watch?v=caHCb...ture=endscreen

Originally Posted by Myriad View Post
Interested.

Respectfully,
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Great.
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Old 26th January 2013, 09:17 PM   #208
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Originally Posted by Myriad View Post
That pyramid of long support trusses must have a high cost in weight and power distribution issues, so the design must have some really big upsides to be worth it.
The design allows all wings to be close to the ground to begin with to gain an advantage from ground effect. Trouble is that advantage all but disappears before you get to the required 3 metres height.
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Old 28th January 2013, 05:32 AM   #209
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ynot, I've been looking through the videos you've posted on this thread and I was wondering. Has anyone tried a really well done single prop made with advanced composites, a drive train optimized to reduce friction, and a sprinter who can put out 1500 watts for short periods of time? Or is it really just impossible without using these giant 4 prop designs?
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Old 28th January 2013, 09:55 AM   #210
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Originally Posted by ynot View Post
Great - I'll keep rambling on then.
Also interested. Have little to contribute, but I've been fascinated with the videos I've seen as well as what I've read here.
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Old 28th January 2013, 10:50 AM   #211
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Originally Posted by Marcus View Post
ynot, I've been looking through the videos you've posted on this thread and I was wondering. Has anyone tried a really well done single prop made with advanced composites, a drive train optimized to reduce friction, and a sprinter who can put out 1500 watts for short periods of time? Or is it really just impossible without using these giant 4 prop designs?
There have been a few but counter-rotation is always a problem with a single rotor set. To have a tail rotor that doesnít provide lift is a waste of energy you donít have enough of to begin with. So most use multiple counter-rotating or off-set rotor sets.

The Upturn uses one set of rotors that are self-rotated with props at the ends of the rotors so no counter-rotation is created.- http://www.ntsworks.com/New_Helicopter.html

The Da Vinci had some sort of prop (not at a tail) but it didnít stop it from counter rotating. I think this was the first HPH to ever get off the ground (I could be wrong) - http://www.youtube.com/watch?v=vYmF7-JWCVA

I Havenít seen any HPH attempt that uses two pilots so if nothing else my attempt would at least be original (no prize for that tho). My design uses two coaxial, counter-rotating wing-sets and the power of the pilots is applied directly to the wings so there is essentially no drive train.
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Old 28th January 2013, 10:56 AM   #212
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Originally Posted by CynicalSkeptic View Post
Also interested. Have little to contribute, but I've been fascinated with the videos I've seen as well as what I've read here.
Thanks. I guess that this thread has had over 5,000 views should be an indication that some people are interested even if they aren’t posting.
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Old 31st January 2013, 11:30 AM   #213
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[delurk]
Interested. I hear Lance Armstrong may be available. I didn't see anything in the rule set about doping.
[/delurk]
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Old 31st January 2013, 12:53 PM   #214
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Originally Posted by CriticalThanking View Post
[delurk]
Interested. I hear Lance Armstrong may be available. I didn't see anything in the rule set about doping.
[/delurk]
Sorry but the rules state . . .

"4.2.3 No drugs or stimulants shall be used by any member of the crew. An assurance must be given to the official observers at the time of the attempt that this requirement has been met."

Lance could try lying of course.
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Old 1st February 2013, 05:11 AM   #215
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Maybe you could get Mark Cavendish to do it. A world record with a nice vacation in New Zealand, why not.
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Old 1st February 2013, 11:53 AM   #216
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Originally Posted by Marcus View Post
Maybe you could get Mark Cavendish to do it. A world record with a nice vacation in New Zealand, why not.
My design uses two pilots so does Mark have a twin brother? It also uses more of a rowing action not pedalling so perhaps top rowers would be a better choice. NZ just happens to have quite a few world class rowers. Of course my design will be so effective and efficient any two reasonably light, strong and fit people will do the job (what, me deluded?) .
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Old 1st February 2013, 12:06 PM   #217
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I’m building my frame and transmission but every time I think I have a final design and get half way through building it I think of some improvement and have to start over. Hope this time I will get it completed but I don‘t mind delays for improvements. Although I‘m using low-tech aluminium and some bike bit’s I’m confident that the frame/transmission is going to be lighter per pilot than any other design I‘ve seen. Maybe even lighter regardless. Did I mention it will also be more effective and efficient? Oh yes I did
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Old 1st February 2013, 12:22 PM   #218
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Originally Posted by ynot View Post
Thanks. I guess that this thread has had over 5,000 views should be an indication that some people are interested even if they arenít posting.
Interested just don't have much to contribute so I lurk.
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Old 1st February 2013, 12:23 PM   #219
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Originally Posted by ynot View Post
Iím building my frame and transmission but every time I think I have a final design and get half way through building it I think of some improvement and have to start over. Hope this time I will get it completed but I donĎt mind delays for improvements. Although IĎm using low-tech aluminium and some bike bitís Iím confident that the frame/transmission is going to be lighter per pilot than any other design IĎve seen. Maybe even lighter regardless. Did I mention it will also be more effective and efficient? Oh yes I did
Pics?

Please.
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Old 1st February 2013, 12:57 PM   #220
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Design change update . . .

Iíve changed the action of the pilots from what Iíve previously explained. To begin with I had the two pilots applying their energy (push/pulls) directly against each other (pilot to pilot) to prevent counter-rotation. This wouldíve required the energy of both pilots to be constantly equally and oppositely balanced. I didnít think this would have been much of a problem to achieve but others did.

Iím now using more of a rowing action and each pilot will be pulling with their arms against a push with their legs so the opposing forces cancel each other out in a counter-rotation sense. The actions of the pilots are now independent of each other and as one is ďresettingĒ the other is ďpoweringĒ so there always a constant application of energy to the wings. As the reset stroke is much faster then the power stroke most of the time both are on the power stroke. Previously each pilot moved one wing-set each but now they both move both. The pilots arenít on sliding seats as with rowing as this would require them to be wasting energy moving their body weight and would also create more overall imbalance. They are now both sitting upright which is possibly more ergonomic than the previous up-down configuration.

So now the overall design is - Two coaxial counter-rotating wing-sets with two pilots positioned below them. The pilots use independent rowing actions to provide the power.
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Old 1st February 2013, 01:30 PM   #221
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Originally Posted by tsig View Post
Pics?

Please.
Don’t really have anything built enough at this stage to provide any pics of. I’m also not completely comfortable publishing exact details of everything until it‘s all closer to being completed. Not sure if this is inventors paranoia or there is any real danger that others might borrow my ideas and use them before I do. I appreciate how open some other teams are with their information but they have been working on their attempts for years and are essentially only copying and improving the earlier attempts of others. I’m trying to be as descriptive as I can with words so that anyone with reasonable mechanical ability should be able to get the pic in their mind. Might post some schematic drawings to make general concepts clearer if I get time to draw them.
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Old 2nd February 2013, 05:35 AM   #222
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Originally Posted by ynot View Post
My design uses two pilots so does Mark have a twin brother? It also uses more of a rowing action not pedalling so perhaps top rowers would be a better choice. NZ just happens to have quite a few world class rowers. Of course my design will be so effective and efficient any two reasonably light, strong and fit people will do the job (what, me deluded?) .
My bad, I should have paid closer attention.

I'm not so sure using rowers instead of cyclists will improve the strength to weight ratio, many of the top cyclists are already running heart rates over 200 during a sprint.

I would love to see you succeed, though, I'm pulling for you.

ETA: I had assumed your design would be heavier, but I see you think it will be lighter. I guess we will have to wait for the video if you are not going to post pics.

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Old 2nd February 2013, 12:41 PM   #223
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Originally Posted by Marcus View Post
My bad, I should have paid closer attention.
No worries.
Originally Posted by Marcus View Post
I'm not so sure using rowers instead of cyclists will improve the strength to weight ratio, many of the top cyclists are already running heart rates over 200 during a sprint.
The power to weight ratio of a particular person is what it is regardless of whether itís applied to pedalling or rowing. For this particular HPH competition that only requires a straight up and down flight for 60 seconds I donít think pedalling is the best method to use. My whole attempt is based on this belief and if Iím wrong I will fail.
Originally Posted by Marcus View Post
I would love to see you succeed, though, I'm pulling for you.
Thanks.
Originally Posted by Marcus View Post
ETA: I had assumed your design would be heavier, but I see you think it will be lighter.
ThatĎs my conclusion from what IĎve developed so far. When Iíve completely built a design IĎm please with I will give the exact weight. Remember what IĎm talking about doesn't include the wings yet.

Originally Posted by Marcus View Post
I guess we will have to wait for the video if you are not going to post pics.
If you were in my position would you publicly post exact and complete details of every unique, innovative, deluded idea you were spending time and money on developing? Remember Iíve only been actively at this for a few weeks and donĎt have anything I can call a final design to post pics of yet anyway. Video at 6:00 .
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Old 2nd February 2013, 12:56 PM   #224
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Hereís a basic concept pic of an earlier design that has been improved . . .

chopperX.jpg
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Old 2nd February 2013, 03:58 PM   #225
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While we are waiting for the engineers to chime in, perhaps you won't mind some more amateurish questions.

This twin rotor design is more ascetically pleasing than the 4 rotor designs. You'd think that smaller blades (a few meters?) turning at a greater rpm, perhaps with adjustable pitch, would be the ticket. Yet, someone must have done the calculations and decided that those gymnasium filling machines were the best options. Have you done some computer simulations of the performance of your designs? It's not that big of a deal these days, a regular PC could do it.
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Old 2nd February 2013, 04:32 PM   #226
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Originally Posted by Marcus View Post
While we are waiting for the engineers to chime in, perhaps you won't mind some more amateurish questions.

This twin rotor design is more ascetically pleasing than the 4 rotor designs. You'd think that smaller blades (a few meters?) turning at a greater rpm, perhaps with adjustable pitch, would be the ticket. Yet, someone must have done the calculations and decided that those gymnasium filling machines were the best options. Have you done some computer simulations of the performance of your designs? It's not that big of a deal these days, a regular PC could do it.
For human power I think bigger and slower wings are better than small and fast. The Yuri design used by Gamera and Atlas have as much wing area as close to the ground as possible to maximise the advantage of ground effect. Trouble is this advantage all but disappears before you get to the 3 metres height required. Not sure how many wings per set my design will have but it could be as many as six. Not working on wings yet other than a collection of possible ideas. I tend do do practical building and testing rather than theoretical.
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Old 3rd February 2013, 05:04 AM   #227
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Originally Posted by ynot View Post
For human power I think bigger and slower wings are better than small and fast. The Yuri design used by Gamera and Atlas have as much wing area as close to the ground as possible to maximise the advantage of ground effect. Trouble is this advantage all but disappears before you get to the 3 metres height required. Not sure how many wings per set my design will have but it could be as many as six. Not working on wings yet other than a collection of possible ideas. I tend do do practical building and testing rather than theoretical.
I am wondering about the feasibility of having two pilots-motors. If one person can't generate enough force to lift themselves how can two since with two you're doubling the weight, yes you're doubling the power but since the original 'engine' could provide enough energy then why would two?

Did the multi rotor design happen solely because of ground effect or also because it's hard to build one wing that's theoretically big enough while also having enough mechanical robustness?

Good luck, we all pulling for you.

ETA: I see where the counter rotating problem might dictate at least two 'mains'.

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Old 3rd February 2013, 05:14 AM   #228
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Originally Posted by ynot View Post
Hereís a basic concept pic of an earlier design that has been improved . . .

Attachment 27557
I like the direct drive for it's simplicity but I wonder about the required rotor RPM matching the human output.
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Old 3rd February 2013, 09:30 AM   #229
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Originally Posted by tsig View Post
I like the direct drive for it's simplicity but I wonder about the required rotor RPM matching the human output.
That's where variable pitch would come in handy.
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Old 3rd February 2013, 09:52 AM   #230
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I think human-powered helicopters are a little too marginal to use variable pitch for impedance matching.
Ideally, you'd like for the entire rotor blade to be at the max L/D angle of attack. Any other AOA requires more power input for the same amount of lift.
I think instead you'd be better off to scale the rotor length so the load matches the power source.
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Old 3rd February 2013, 10:25 AM   #231
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Okay, but he better know how much combined power his athletes are going to be producing on the day.

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Old 3rd February 2013, 10:25 AM   #232
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Originally Posted by ynot View Post
Donít really have anything built enough at this stage to provide any pics of. Iím also not completely comfortable publishing exact details of everything until itĎs all closer to being completed. Not sure if this is inventors paranoia or there is any real danger that others might borrow my ideas and use them before I do. I appreciate how open some other teams are with their information but they have been working on their attempts for years and are essentially only copying and improving the earlier attempts of others. Iím trying to be as descriptive as I can with words so that anyone with reasonable mechanical ability should be able to get the pic in their mind. Might post some schematic drawings to make general concepts clearer if I get time to draw them.
I know the feeling about the level of sharing details. I haven't wanted to share much until the day of public launch.

Originally Posted by ynot View Post
I had doubts from day one that Dan would ever post any actual details of his rotors/wings. He doesn't have to of course but it seems pointless to start a thread in this section of the forum and just say he has a dream but it hasn't gone well it practice.

Probably best if he doesnít post details because I donít think he could take the honest feedback he would get. He would call it something different.
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Old 3rd February 2013, 11:52 AM   #233
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Originally Posted by tsig View Post
I am wondering about the feasibility of having two pilots-motors. If one person can't generate enough force to lift themselves how can two since with two you're doubling the weight, yes you're doubling the power but since the original 'engine' could provide enough energy then why would two?

Did the multi rotor design happen solely because of ground effect or also because it's hard to build one wing that's theoretically big enough while also having enough mechanical robustness?

Good luck, we all pulling for you.

ETA: I see where the counter rotating problem might dictate at least two 'mains'.
Iím assuming with this design that each pilot could independently power and fly with one of the wing-sets. In other words as if it were two separate choppers. If one pilot could get of the ground with one wing-set then two pilots should be able to with two wing-sets. As both pilots share the weight of the fame it should be slightly better than as if it were two separate choppers. If IĎm wrong it wonĎt fly.
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Old 3rd February 2013, 11:53 AM   #234
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Originally Posted by TjW View Post
I think human-powered helicopters are a little too marginal to use variable pitch for impedance matching.
Ideally, you'd like for the entire rotor blade to be at the max L/D angle of attack. Any other AOA requires more power input for the same amount of lift.
I think instead you'd be better off to scale the rotor length so the load matches the power source.
Would you vary the angle of attack along the blade since the tip if the blade moves much faster than the base?
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Old 3rd February 2013, 12:02 PM   #235
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Originally Posted by ynot View Post
I’m assuming with this design that each pilot could independently power and fly with one of the wing-sets. In other words as if it were two separate choppers. If one pilot could get of the ground with one wing-set then two pilots should be able to with two wing-sets. As both pilots share the weight of the fame it should be slightly better than as if it were two separate choppers. If I‘m wrong it won‘t fly.
If one pilot can do the job doesn't two pilots just double your trouble?
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Old 3rd February 2013, 12:02 PM   #236
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Originally Posted by tsig View Post
I like the direct drive for it's simplicity but I wonder about the required rotor RPM matching the human output.
The current main contenders have a wing speed of around 1 revolution per 5-6 seconds. Iím planning on having larger wing areas (more like plane wings) that may give enough lift at an even slower speed. How many RPS you need also obviously depends on how long the wings are. Given the direct transfer of the human power from all limbs for most of the time with this method I think more lift will be able to be generated per pilot than other designs.
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Old 3rd February 2013, 12:04 PM   #237
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It might work that way. But I suspect that the pilot will be the least-optimized part of the helicopter, and that keeping the percentage of non-optimal parts to a minimum is the better strategy.
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Old 3rd February 2013, 12:09 PM   #238
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Originally Posted by tsig View Post
If one pilot can do the job doesn't two pilots just double your trouble?
Two pilots save some weight by sharing the same frame and they provide a human "differential” to provide direct drive counter-rotation (no gears, pulleys, chains, etc). It’s also easier to balance two pilots than one for this direct drive system.
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Old 3rd February 2013, 12:10 PM   #239
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Originally Posted by TjW View Post
I think human-powered helicopters are a little too marginal to use variable pitch for impedance matching.
Ideally, you'd like for the entire rotor blade to be at the max L/D angle of attack. Any other AOA requires more power input for the same amount of lift.
I think instead you'd be better off to scale the rotor length so the load matches the power source.
I agree.
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Old 3rd February 2013, 12:12 PM   #240
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Originally Posted by tsig View Post
Would you vary the angle of attack along the blade since the tip if the blade moves much faster than the base?
Don't know what I will do until I get the the wings stage. Then I will do the simplest thing that works.
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