OK guys, I got a document from the people involved and I am going to share some *select* information. As we are working on several prototypes you'll understand why we aren't sharing it all. but I'll tell you some more about the study with some direct quotes from the engineers.
in some places I am quoting them directly, JOHN T, ALEX B, STEVEN M, JOSH K 2016
The info may not flow like you're expecting and these are just from one round of things. Taking a break for the summer and going back at it in the fall. (though we're doing empirical stuff with the prototype all summer)
Data from initial testing:
Our study determined that the ergonomic of mermaid tails posed the biggest problem, as blisters would start forming on feet within 15 minutes of constant use. The energy transfer between the tails and the person was at the feet and ankle region. This is the area that experienced the most loading. (hehe I mean we all know this, just nice to have science back it up)
The prototype and suggested changes from the engineers brought the time up to 2 hours totally blister and pain free.
Our team for our purposes wanted to focus on maneuverability over speed.
Quote:
“As it would translate to smaller monofins being used to provide less thrust while maintaining a smaller profile in the water so that smaller areas of water can be traversed. A smaller surface would also result in smaller drag forces”.
Our company decided to prioritize this over speed in the testing because we felt our company relied more on it than speed for our intended use of mermaid tails.
The tails were 2.5% more buoyant in salt water than fresh (it certainly feels like a lot more).
As quoted from the document, these are the goals for the project that we started out with:
Quote:
“
1. Swimmer must be able to swim with Mermaid tail for 4 hours (safety factor of two for average session time) with no complaints of blisters or soreness due to the foot securing apparatus.
2. Foot securing device should be able to withstand 2772 N-m moment at the connection point. This will be tested by subjecting the device to a 2705 N drag force or a deflection at the center of the monofin of 1.33 mm. This deflection was found using a carbon fiber model.
3. Prototype design must perform 20% better in timed swimming trials relative to the existing mermaid suit design.
4. A system in the tail that would allow for the adjustment of buoyancy in the water depending on the situation (accounting for 2.5 % difference in water densities). “
After some testing and realizing that #1-3 would require more work than initially expected and more baseline testing, we shelved #4 for the time being.
The engineering team came up with a few ideas that were tested to a degree but ultimately scrapped. One involved a system that would allow for buoyancy control and increased comfort in the foot pockets. In theory the buoyancy plan they had would compensate for the differences in salt and fresh water. It may still be an avenue we explore later on down the road. There’s a whole bunch of amazing data that comes with this haha but we are giving that data to merbellas first to see if they want to test that specific idea.
They also did some baseline testing on extended flukes that go way past the feet like h20.
Instead they focused on the various prototypes I’ve been sharing details about, which make monofins hands free and easier to get off and on and reduce the stress on ankles and heels.
In the testing they really did find that excess silicone past the monofin was a key problem in increasing buoyancy. They found that the foil was the most reliable in achieving maneuverability and putting less stress on the person.
Here were the main goals we looked at for testing:
Quote:
“
1. Mermaids will perform time trails in three different swimming scenarios: wearing a mermaid tail that was already owned by the group, wearing a monofin, and wearing no equipment.
2. During these (control) time trials, Mermaids will wear an accelerometer on their ankle to assess the acceleration and speed that arises during swimming.
3. Once the new monofin and foothold prototype has been assembled, the time trials will be repeated to compare performance with the control trials.
4. The accelerometer data will be captured in the same manner with the second time trials to compare performance with the control time trials and the tow tank data (see #6).
5. The team will elicit feedback regarding how the new prototype performed in terms of maneuverability and comfort.
6. The monofin and prototype will be tested in a tow tank at various speeds while recording the drag force on the monofin. This will allow the group to determine whether or not the foothold system can withstand the drag force created by the swimming.
7. Material testing will be performed on monofin plastic to determine material properties. “
“For the purposes of determining the difference in swimming speeds for different methods of propulsion, swimming time trials were performed at the Aquatron. Mermaids were asked to perform time trials in the following equipment:
1. With current Mermaid tails
2. With a monofin
3. With no swimming aids
Quote:
All swimming tests were performed in the same manner to ensure consistency. The following tests were performed with each of the aforementioned equipment types:
1. Steady swim: Time for Mermaids to swim at their own pace for one length of the Aquatron. This was more for acceleration data than time trials.
2. Fast swim: Time for Mermaids to swim as fast as they were able to for one length of the Aquatron.
3. Roll: Time for Mermaids to perform one horizontal roll while swimming forwards.
4. Flip: Time for Mermaids to perform one flip backwards or forwards underwater.
5. Turn (no wall): Time for Mermaids to swim from the center of the Aquatron to the wall and back to the center without pushing off the wall.
6. Turn (with wall): Time for Mermaids to swim from the center of the Aquatron to the wall and back to the center after pushing off the wall. “
Here were our timed trials.
Mimi tested my old rapidash in a competitor monofin
Emma tested our blue tail in a competitor monofin
I tested my current orange tail with a foil
Nessie tested my franken tail with a wave
Vitoria tested she creature with a foil
You can see from the data that certain tails are a lot slower compared to the person swimming with just a regular monofin. But still much faster than just bare legs. Interesting to note that Nessie was only 1 second slower than I am with her bare legs, and me in my tail. I’m telling you my tail got drag.
Attachment 36512
Attachment 36513
(not all the data is here for the other swimmers so you’ll only be able to compare a few)
And here is the accelerometer data we collected as well:
Attachment 36514
^like I said not everything is included these are just a few examples pulled. There's pages and pages, these are averages, and not every mer at this moment.
I’m not gonna publicly share the prototype data yet it’s better in some areas, not as great in others, but is still a prototype and being worked on.
You’ll see I referenced a tow-tank frequently. Here’s a fun photo by the engineers of the monofin in a tow tank!
Attachment 36515
They tested the drag as speed was increased (m/s) and the drag increased as speed increased. There’s a whole bunch of charts and graphs that go with that but it’s combined with prototype data so I won’t be sharing it at this time.
A few interesting points discovered during testing:
Quote:
-“It is important to note that all of the maximum velocities were found to occur when the Mermaids were performing either a turn (with or without the wall) or a roll. This is partially because the acceleration at these times was occurring in multiple planes and the magnitude of the acceleration peaked at these times. It is also because these maneuvers required the longest dolphin kick strokes. These were noted as times of high drag force, which makes for uncomfortable feet while swimming.”
-“As the tow tank trolley increased in speed, it was found that the monofin deflected a significant amount. This deflection increased as the speed of the trolley increased, and the drag on the monofin leveled out to 70 N at 2.0 m/s.”
-“The small modulus of elasticity of the plastic in testing confirmed our results in the tow tank where the monofin had a significant deflection. The amount of deflection could not be determined throughout the tow tank testing. However, it was noted that the vertical ridges formed in the monofin do not keep the fin flat in the water when traveling at high velocities”
I know that's a wee bit all over the place but it should make more sense when you see my next round of videos (I have just had NO time to edit them all together)
