Lunocet progress

[jome]

Haven't seen much discussion about the Lunocet lately so I thought I'd share this:
Lunoblog: An online community for Lunodivers.

Seems like the project is well alive and kicking! Cool videos of prototype testing for example...

[trux]

Ah, I see it is already for sale for $1250 (the cheapest model). I know Ted asked for testers here on DB, so I wonder if anyone here on DB already tested it.

[whucash]

Nice video on the site..but still for me it doesn't look like it would make any difference than normal monofi..furthermore when it comes to efficiency the standard looking one would be better..
And the price..the best model costs 1800$..quite some money isnt't it

[trux]

The main difference is in the way the fin creates the propulsive force - unlike at monofin, the entire blade generates propulsion, because it swaps into the optimal angle of attack (assuming the gear is properly adjusted to your speed). From this point of view it is indeed more efficient. On the other hand it has two inefficient zones at the end of the kick movement, when the blades reverse. That is the case at monofin too, but due to the flexibility of the blade (forming a wave form), it is less abrupt, and the movement is hence more continuous.

It remains to see if Lunocet really performs better. The main problem with the video is that it is not an experienced monofin swimmer using it there, so the style is certainly not optimal. But I think that even an experienced monofin user will need a time to find the right style for the Lunocet. On my mind, to avoid the efficiency loss during the kick direction reversal, it might be better using slow high amplitude kick. Very likely movement coming from the back (just like at monofins) would be better than those coming from knees (like on the video).

PS: if you select custom design, you can get even more expensive one - $2050
I agree, it is (still) a lot of money, but with the dollar tendency soon it won't be more than common monofins from European manufacturers

[whucash]

Yeah the custom one is the most expensive..2000$ its really extremely hihg price for something that hasn't been tested so much yet.
As for the lunocet itself..the style this guy is using looks so unefficient..he uses only legs not the back..and he almost stays in one place..in normal monofin even such style gives power for moving.
I'm waiting for some good freediver with good technique and good depth to compare the results on normal monofin and the lunocet.
And if it requiers different technique from the diver but gives back extreme efficiency..yeah i would go for it..
Cheerse

[zerog]

Hi Guys,

I have been wanting to update you for a while but frankly was embarrassed to say that there have been setbacks in the design. The six speed tensioner system, although working, was not providing enough bang for the buck. Sixth speed or maximum rigidity for a Lunocet, provided you can actuate the foils to the proper angle with maximum input, is the preferable setup... I had envisioned a variable spring through six different speeds providing the option for dialing in the type of swimming... slow aerobic to fast anaerobic. But it turned out that the ankles and knees can augment the pitch angle as speed ramps up.

There were several other changes that were made that deviated from the titanium foil prototype that I hadn't realized were important until they were changed. Some of you pointed out that they thought it was a mistake to take out the center section between the foils... that there would be spillage coming from opening that up that would spoil the flow over the foils... you were right. I had thought it was a risk to do it but incorrectly banked on relieving the "dirty" water coming off the feet as a better choice. Also, another interesting thing, albeit unfortunate, happened when I moved the pitch axles back... I moved them back thinking that I would create a faster flip of the foils at the ends of the strokes and also to have the forces on the surface of the foils more balanced to allow for a weaker return spring... the idea works like a charm as long as you are static - oscillating the foil but no forward movement... the problem occurs when you start to gain speed; the flow over the foil starts moving the center of pressure forward to the point that it no longer actuates the foil!!!

Anyway, I'm very sorry I jumped the gun on confidently promoting unproven design features... I have built over ten designs in the past nine years with each one being a step forward... I didn't think I'd fumble.

So, where am I now?... I am scrambling to get these design changes made and get the new design to market... my website designer has been ahead of me so we have a few things to undo and change in the presentation. Here are some pics and comment on the last few months of activity... Lunoblog

[trux]

Thank you for the information, Ted! Sorry to hear about the setback, but hope you sort it out soon.

I moved them back thinking that I would create a faster flip of the foils at the ends of the strokes and also to have the forces on the surface of the foils more balanced to allow for a weaker return spring... the idea works like a charm as long as you are static - oscillating the foil but no forward movement... the problem occurs when you start to gain speed; the flow over the foil starts moving the center of pressure forward to the point that it no longer actuates the foil!!!

I think your idea is right, and the effect you experienced is in fact desirable too (you need less actuation with growing speed), so I suppose you only need to find the exact point so that it does not come too early. The hydrofoil works in its best efficiency when it does not need to flip at all at high speeds - there is then no flipping and thrust loss at the end of the movement. All the necessary angle comes just from the profile of the hydrofoil, not from the pitch of the entire blade. However, at the relatively low speeds human can achieve, it would require a rather thick hydrofoil to move in this fixed mode efficiently. And that has then a lot of drag, so you are probably right that the fixed hydrofoil (with no actuation at all) is likely not something desirable (though there is still always certain flexibility of the feet that adds to the pitch).

There are some complex formulas and charts explaining the calculation of the right fixation of a self-sustaining hydrofoil in the section hydrofoil auto-incident of the document http://mshades.free.fr/flapping/caudale.html (at the bottom of the document). It is in French, but possibly the author would be willing to help you finding the optimal solution - there is a contact form at the bottom of the page.

PS: just for the reference - some of the past discussion was for example in this thread: http://forums.deeperblue.net/monofins/75673-who-dares-suggest-reason.html

[trux]

Just a note: I've just added the RSS from the Lunocet blog to the news feed at APNEA.cz, so if you watch freediving news there, or are subscribed to the RSS or Google news feeds available there, you won't miss new posts to the Lunocet blog either.

[zerog]

thanks trux!

[ADR]

Hi Ted,

The current setbacks maybe the very things that bend your mind to further innovation and insights. I think you are going to create an awesome product that redefines underwater human propulsion and makes the current thinking obsolete. Maybe a dark few hours for you at the moment but I'm betting.....with a deposit if you like, that you will solve the issues and we will be the beneficiaries.

Keep going pal !

Respectfully

[zerog]

Thanks Andy.

[Ol Dirty Diver]

Originally Posted by zerog

I'm very sorry I jumped the gun on confidently promoting unproven design features... I have built over ten designs in the past nine years with each one being a step forward... I didn't think I'd fumble.

So, where am I now?... I am scrambling to get these design changes made and get the new design to market... my website designer has been ahead of me so we have a few things to undo and change in the presentation. Here are some pics and comment on the last few months of activity... Lunoblog

Ted,

I don't think anyone here is critical of the delay, much less even feels that you should have to work under any deadlines. You're on the cusp of making a tremendous leap in underwater self-propulsion...Don't be concerned with the market or us. I've followed the evolution of the Lunocet for years now, and I'm happy to see that you haven't released it hastily in order to meet the market release dates you predicted early on. Several renditions ago it was probably already a higher-performing design than our current monofins, but you are obviously a perfectionist. You will not release your invention until it is the best possible design you are capable of creating, which is to be admired.

I wanted to share with you an idea for when you do get around to marketing the Lunocet aggressively. Have you seen the Seabob? I only just ran across it, and I've got to say that the intro video on their site really impacted me. I have otherwise no interest in motor-propelled recreation devices, preferring self-propulsion (road bikes, sailboats, etc.), but I had to add the Seabob to my wishlist after seeing that video. So you should feature a similar HD video on your site, with a smooth soundtrack and happy enthusiasts. I believe this would be consistent with your early vision of the Lunocet's application...A popular and widely-used tool of recreation for vacationers, perhaps as essential to pack for a trip to the tropics as one's golf clubs or camera.

Bring that Lunocet out to Hawai'i! I think the crystal clear waters off the Kona coast would be a much better setting for gathering promotional media than that green lake you excavated in your backyard. The divers out here would be glad to help you.

[zerog]

Thanks Kurt...

I did check out the video... amazing what is possible with lithium-ion batteries these days!

[Kars]

What's up about the Lunoced being to a Mexican AIDA competition?

Lunocet To Make An Appearance At The 2nd AIDA Mexican Championships by Nicolas Danan on DeeperBlue.net - Fanatical About FreeDiving, Scuba Diving, Spearfishing & Technical Diving

I have checked the blog but couldn't anything about this announcement?
I'm looking forward to seeing an UW video of an able -professional- monofinner using the lunocet in a 50m pool, trying out different speeds, different strokes etc.

These 'setbacks' are just learning bumbs that allow one's understanding to grow.

On the US currency thing. All currencies are being devalued rapidly, as the Central Banks create more and more money without any backing of any commodity. But indeed the US Dollar seems to lead the way. For some people with some money in the bank it maybe disturbing that their given intrest is far below the actual inflation.
The central bankers are already hinting of wanting a global currency, where visionaries and thinktanks have already have 'predicted' these and other societial devellopments decades ago.

Love, Courage and water!

Kars

[Ol Dirty Diver]

Originally Posted by trux

The main problem with the video is that it is not an experienced monofin swimmer using it there, so the style is certainly not optimal.

Originally Posted by whucash

the style this guy is using looks so unefficient..he uses only legs not the back..and he almost stays in one place..in normal monofin even such style gives power for moving.
I'm waiting for some good freediver with good technique and good depth to compare the results on normal monofin and the lunocet.

Originally Posted by Kars

I'm looking forward to seeing an UW video of an able -professional- monofinner using the lunocet

You guys might want to take it easy with being so critical of the diver in the Lunocet videos if you hope to get your hands on one...I'm pretty sure that's Ted!