Ynot’s Human Powered Helicopter Attempt

[TjW]

Sure. It decreases span loading, decreases wing loading, and increases aspect ratio, all good things from a power-reduction standpoint. The only drawback I can see is the increased weight to take the increased bending moment.
Open class sailplanes go up to about 30 meter span.
The tip is moving faster, and so the amount of lift that extended area can generate is larger than a similar area nearer the hub. So you can slow the whole rotor down a little bit compared to the original rotor, reducing drag on the inner part of the rotor for the same overall amount of lift.

[ynot]

Originally Posted by TjW

Sure. It decreases span loading, decreases wing loading, and increases aspect ratio, all good things from a power-reduction standpoint. The only drawback I can see is the increased weight to take the increased bending moment.
Open class sailplanes go up to about 30 meter span.
The tip is moving faster, and so the amount of lift that extended area can generate is larger than a similar area nearer the hub. So you can slow the whole rotor down a little bit compared to the original rotor, reducing drag on the inner part of the rotor for the same overall amount of lift.

One of the difficult decisions to be made (when I get to the wings) is exactly how far out from the hub to start the wings. The distance the Upturn uses seems about right to me for long wings. Although a greater number of shorter wings starting even further out might be better. I think slow rotation with wings extending to a large diameter is best for human power. It’s all wings and roundabouts

[tsig]

Originally Posted by AmishmanDan

Does truth need to be draped with a spirit? If someone asked me a question, I can answer with a very true statement, that is mean spirited. I can also offer unsolicited truth that is mean spirited.

Denying reality is not the same as filtering reality. Truth is often packaged within opinion.

So's BS.

[TjW]

Originally Posted by ynot

One of the difficult decisions to be made (when I get to the wings) is exactly how far out from the hub to start the wings. The distance the Upturn uses seems about right to me for long wings. Although a greater number of shorter wings starting even further out might be better. I think slow rotation with wings extending to a large diameter is best for human power. It’s all wings and roundabouts

Make a spreadsheet.
For every foot or so along the rotor, calculate:
The lift from your chosen airfoil at that station airspeed at best L/D alpha.
The airfoil drag at best L/D
The estimated weight of the airfoil structure at that station.
The estimated weight of the spar alone.
Where the drag of the airfoil is less than that of the bare spar and the lift generated is greater than the difference between spar and airfoil structure weights, having an airfoil there is a net benefit.

At some point near the hub, either the airfoil will be draggier than the spar alone, or more likely, the lift generated will become less than the additional airfoil structure.

Excel and OpenOffice both have a goal-seeking tool, so if you sum the lift generated, you can use the spreadsheet to iteratively change the rotation speed until the sum of lift matches your estimated machine flying weight.
You should be able to calculate the torque required from the drag values and their moment arms. That and the rpm should estimate your power required.

[ynot]

Thanks - Didn't know OpenOffice had that function.

[ynot]

Finally found a clip of the Upturn being “flown”. Well the wings go around but it doesn’t appear to gain any height - http://www.youtube.com/watch?v=wkNI3WwntBc

[quarky]

Greetings, aero-freaks.
Been away for a month, but I'm still intersested.
The most recent you-tube I've seen looked like the Gamera team was honing in on it, fast.
They got good altitude; decent endurance...
The issue looked like a control issue...staying in that 10 meter box.

Ynot?

Any advances in your game?
(All ears.)

quarky

[ynot]

Welcome back quarky. I’ve had a bit if illness lately that has slowed me down but nothing too serious.

The Gamera Team say - “The team is currently designing a control system to remain within the required 10m x 10m box during flight, and that we will be flying in late winter/early spring 2013 with our sights set on the AHS Sikorsky Prize” so their next attempt shouldn’t be too far away.

I think they have a better chance of success than the Atlas Team but I don’t think they’re as close as others seem to. It’s much easier to achieve things in separate flights than it is to put them altogether in one flight. I’m really interested to see the design of their “control system” and how well it works. I didn’t much like what the Atlas Team came up with and it seems to have created more problems than it solved.

[ynot]

Originally Posted by quarky

Ynot?

Any advances in your game?
(All ears.)

quarky

Perhaps more of a step back/sideways than advance. My illness enforced break from building has given more time for thinking and reflecting. I still think the two person design I’ve explained earlier is the “best” design but perhaps not the best to build as a first attempt for a backyard inventor with limited resources. The frame is simple and easy and I’ve practically built it, but I would have to build at least twice the wing area as I would for a single pilot design. Given the wings will be the most complex and expensive things to build and get right I’ve changed (yet again) to a single pilot design with two counter-rotating wing-sets. The counter-rotation is achieved by pulling lines from spools on the centre-shafts of the wing-sets as shown in the pic below.

cr.jpg

[CynicalSkeptic]

another non-pedal prototype:

http://www.youtube.com/watch?v=BAD_e-tGpoM

[ynot]

Originally Posted by CynicalSkeptic

another non-pedal prototype:

http://www.youtube.com/watch?v=BAD_e-tGpoM

I linked to that clip earlier in the thread.

Originally Posted by ynot

Some amusing attempts at HPH flight . . .

A prop powering wing attempt - http://www.youtube.com/watch?v=QXRZ6u04Dno

Test bed - http://www.youtube.com/watch?v=8TGnPTZFseE

The things some people do in their bedroom - http://www.youtube.com/watch?v=0Fkk17rtrSc and http://www.youtube.com/watch?v=_ZPUsclllUs

Beats mowing the lawn I guess - http://www.youtube.com/watch?v=BAD_e-tGpoM

Did anyone really think this would actually fly? - http://www.youtube.com/watch?v=PiMWzebn-DM

Wonder if I will have to add my attempt to this “amusing” list?

Hope that attempt isn’t used as an example of pedalling being the best method.

[rjh01]

Originally Posted by CynicalSkeptic

another non-pedal prototype:

http://www.youtube.com/watch?v=BAD_e-tGpoM

When I was a small kid I had a toy car that was powered by a similar method. Only thing was that only one leg was stretched out at any one time.

[ynot]

Team Gamera are resuming test flights tomorrow. No mention of their new flight control system but they have “removed 130 grams (over a quarter pound) in excess duct tape!”.

[JoeTheJuggler]

Originally Posted by ynot

Team Gamera are resuming test flights tomorrow. No mention of their new flight control system but they have “removed 130 grams (over a quarter pound) in excess duct tape!”.

I don't guess we'll know that they were correct in determining that that duct tape was "excess" until after the test flight!

[quarky]

It is somewhat mind-boggling how little these monster rigs weigh.
This is cutting-edge architecture and engineering.

Yet, compared to high-end bikes, the weight ratio of passenger to vehicle is un-impressive.
There are 10 pound bikes that can be ridden fast by 200 pound jocks.
That's pretty amazing.

Yet, they don't hover.

When this prize gets won, we should all rejoice in the accomplishment.
It's been a long time coming.

[ynot]

Nothing on their website yet but on Twitter the Gamera Team say their new control system is working well - “Austin just had a smooth 38 sec ~2 ft flight using the new control system to stay in the box!” and - “Austin just flew a 4 ft 35 sec”. Can’t see from the few photos on Twitter exactly what their control system is.

Seems they’re about to have a go at the prize - “if everything goes well today Wednesday will be an attempt at the prize. Media has also been invited that day“.

https://twitter.com/UMD_Gamera

ETA - Seems to be all systems go - “Observer from AHS has arrived, observer from the NAA will arrive later to inspect the vehicle”.

[ynot]

From this pic https://pbs.twimg.com/media/BECnYQ_CUAAZMNF.jpg:large it appear the control system is something under or behind the seat. There’s a level/handle for each hand with wires running down to the back of the seat. Given it seems to be electrical I hope they’re generating their own power and not using a battery (stored energy).

ETA - They just tried a “long duration flight” that had to be “called down for drift” after 40 seconds, so perhaps the new control system isn’t working so well. At least they don’t have a shortage of pilots. They started the day with Austin then Brandon and now Henry.

[quarky]

Originally Posted by ynot

From this pic https://pbs.twimg.com/media/BECnYQ_CUAAZMNF.jpg:large it appear the control system is something under or behind the seat. There’s a level/handle for each hand with wires running down to the back of the seat. Given it seems to be electrical I hope they’re generating their own power and not using a battery (stored energy).

ETA - They just tried a “long duration flight” that had to be “called down for drift” after 40 seconds, so perhaps the new control system isn’t working so well. At least they don’t have a shortage of pilots. They started the day with Austin then Brandon and now Henry.

Surely, this far into it, they wouldn't use stored energy.

Too bad Lance Armstrong can't be exploited and redeemed in this effort.

[ynot]

Originally Posted by quarky

Surely, this far into it, they wouldn't use stored energy.

I can't see any obvious charging equipment but I’m not sure that what I’ve mentioned is even part of the control system. It might just be some monitoring device that won’t be used during test flights.

[rjh01]

One simple method of control is to tip the whole machine into the direction you want it to go. Like if it is drifting left then the rider leads to the right and the craft moves to the right. The advantage of this method is that no extra machinery , read extra weight, is required.

[quarky]

Originally Posted by rjh01

One simple method of control is to tip the whole machine into the direction you want it to go. Like if it is drifting left then the rider leads to the right and the craft moves to the right. The advantage of this method is that no extra machinery , read extra weight, is required.

I suspect you're right.
Yet, that sort of skill comes with hours aloft; not a few seconds here and there.

Remember learning to ride a two-wheeled bike?

I wonder if the pilot could focus on the weight-shifting angle, if they used a motor for a bunch of test runs...until he got those chops down?

[ynot]

The Gamera Team are going for the AHS prize today. A small piece of transmission “popped off before takeoff” and they're having lunch while the epoxy repair cures. They hope to be flying again in about half an hour.

Photo of repair - https://pbs.twimg.com/media/BEIEAIrCQAAjGVt.jpg:large

ETA - They're flying again and testing short trimming flights.

Photo - https://pbs.twimg.com/media/BEIcpaKCAAA-YK6.jpg:large

[CynicalSkeptic]

Originally Posted by ynot

I linked to that clip earlier in the thread.

Sorry, I missed it. I can't view videos at work, and I rarely go back through and watch every video when I get home. I did watch quite a few and found that one as related when watching some of the more successful attempts.

[ynot]

Originally Posted by CynicalSkeptic

Sorry, I missed it. I can't view videos at work, and I rarely go back through and watch every video when I get home. I did watch quite a few and found that one as related when watching some of the more successful attempts.

No worries. Thanks for contributing.

[quarky]

Originally Posted by ynot

The Gamera Team are going for the AHS prize today. A small piece of transmission “popped off before takeoff” and they're having lunch while the epoxy repair cures. They hope to be flying again in about half an hour.

Photo of repair - https://pbs.twimg.com/media/BEIEAIrCQAAjGVt.jpg:large

ETA - They're flying again and testing short trimming flights.

Photo - https://pbs.twimg.com/media/BEIcpaKCAAA-YK6.jpg:large

I'm curious:
Why would they go for a prize run before they knew they could do it?
Publicity?

I suppose there is no fine, of sorts, for failed attempts...

But can you imagine going for something like a weight-lifting competition, before you were sure that you could lift the weight?

[ynot]

Originally Posted by quarky

I'm curious:
Why would they go for a prize run before they knew they could do it?
Publicity?

I suppose there is no fine, of sorts, for failed attempts...

But can you imagine going for something like a weight-lifting competition, before you were sure that you could lift the weight?

I think Atlas = publicity for fundraising and Gamera = they think they might do it.

[ynot]

They're about to fly a 4 ft test flight - https://pbs.twimg.com/media/BEIsrnZCUAEFUAI.jpg

Wish they would post some vids or have streaming vid.

[ynot]

Well they sure have a good stock of motors - Austin, Brandon, Henry, Colin, Duncan and now his twin bro Henry is having a go (could be the previous Henry).

Last flight was 5 ft 25 secs. Surely they must be getting close to a prize attempt flight. It's nearly 5:30pm their time.

[ynot]

Gamera Team’s latest Tweet - “Henry topped out around 5-6 ft this time, we are breaking for dinner and planning next moves“.

No mention of their new control system and if drift is still a problem. Seems just getting required time and height in a single flight is a problem.

[ynot]

They’ve had dinner, made some adjustments and are trimming again. If nothing else they must have the world record for the most number of human powered flights in a day. It’s 8:30pm their time so I doubt they have time to win the prize today. Don’t know if they will continue tomorrow and the AHS official will stay for another day.

[quarky]

Do you think they are close?

[ynot]

Originally Posted by quarky

Do you think they are close?

Not from the information provided so far. Longest flight seems to have been 50 secs and 5' 6" highest flight with no mention of being able to stay within the 10 metre "box".

According to their last Tweet - "A few main structure members failed" that they are apparently going to repair through the night and try again tomorrow. Not sure if the AHS will still be present to make anything official.

[ynot]

The night shift has repaired the Gamera and it’s flying again. Not sure if they’re still going for the official prize or just conducting test flights now.

ETA - "Austin flew a 60 second low altitude controlled flight!" I guess that means their control system works (at least at low altitude). I still can't see what their control system is. Can anyone else?

[ynot]

I Tweeted Team Gamera and asked if they’re still going for the prize today. Unlike Team Atlas they had the decency to reply - “official prize if possible! But we are taking our time to ensure safety of everyone and the vehicle”.

[ynot]

If I was designing the Gamera I would have the pilot’s butt as close to the ground as possible to lower the centre of gravity. They could lower the weight of the pilot by 30-40cm. I think what they call “drift” is actually more imbalance. Ground effect helps with balance at low altitude but when they get up a metre or two they lose ground effect enhanced balance.

I also think the best strategy would be to hover close to the ground for the first 50 plus seconds then have a burst to try to get to the height required. It doesn’t matter if they drift out of the 10 metre box after the time and height requirements have been achieved.

[quarky]

I assume that the 3 meter height means that the lowest part of the craft must get that high?

If so, that alone could induce some design that otherwise didn't look logical.

I concur with your idea of the 50 seconds of relatively relaxed effort, followed by the burst.


OTOH, why not try to get the height requirement out of the way, at the onset...and then slack off for 50 seconds?

[ynot]

Originally Posted by quarky

I assume that the 3 meter height means that the lowest part of the craft must get that high?

You asked that same question earlier in this thread and the answer is still "yes".

Originally Posted by quarky

If so, that alone could induce some design that otherwise didn't look logical.

At present the lowest part of the Gamera is a 30-40cm high block of styrene under the pilot's bum. I think the lowest part should be the bum.

Originally Posted by quarky

I concur with your idea of the 50 seconds of relatively relaxed effort, followed by the burst.

OTOH, why not try to get the height requirement out of the way, at the onset...and then slack off for 50 seconds?

Because getting to the height requirement causes the craft to become unbalanced and drift (and possibly crash as it has). From recent Tweets they are still having "drifting" problems at height and have given up on the prize for now to extend their flight duration record past 65.1 seconds.

[ynot]

Does anyone know if any HPH has ever got off the ground without using ground effect? If not it seems a big ask to get to 3 metres purely by using the momentum of lift enhanced by ground effect.

ETA - The Upturn's wings are too high to gain any appreciable ground effect and they claim to have hovered for 10 seconds. I haven’t seen any proof of this however and remain sceptical.

[ynot]

Time’s running out for Team Gamera and it’s their last day of testing so baring a miracle they won’t be winning the prize.

BUT WAIT! - “Duncan completed his balancing flights and will go for height attempt now”.

[quarky]

Originally Posted by ynot

You asked that same question earlier in this thread and the answer is still "yes".


At present the lowest part of the Gamera is a 30-40cm high block of styrene under the pilot's bum. I think the lowest part should be the bum.


Because getting to the height requirement causes the craft to become unbalanced and drift (and possibly crash as it has). From recent Tweets they are still having "drifting" problems at height and have given up on the prize for now to extend their flight duration record past 65.1 seconds.

Sorry about repeating myself. Memory sucks.

I agree, the bum should be the lowest part. In fact, perhaps the pilot should be in a prone position?