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Balor
recumbent guru

Russia
514 Posts

Posted - 10/23/2015 :  11:32:37  Show Profile  Reply with Quote
quote:
Originally posted by Grant-53

Tom's Critical Mass II bike looks like it is good starting point. If the nose cross section is heart shaped and round as in Shooky's rib panels the side wind effects would be minimized. To accommodate the MBB movement the side panels might be hinged front and back. I'd try it with a model. If that is not feasible concentrate on protecting the hips, kidneys, shoulders, and head. A seat belt would help too. The Society of Automotive Engineers would have a number of papers available on crash testing motorcycles. Shooky, I was thinking about the top of the nose impacting the throat. Head and neck injuries are by far (90%) the most common cause of death for upright cyclists. Sheet aluminum does not splinter the way typical fiberglass does. Lots to consider. Best wishes Balor




I'd be doing fiberglass (actually, basalt) only for the nose and the tub, or perhaps a just layer of multiaxial cloth around the 'beltline' to save weight.
The protection against impact and abrasion would be handled by polyurea coating:
http://www.youtube.com/watch?v=GHopFM2lAVU
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shooky56
recumbent guru

USA
545 Posts

Posted - 10/23/2015 :  11:45:45  Show Profile  Reply with Quote
Sorry Grant: Meant to respond to you too and my delay typing up a reply put two posts (one with the link again) between Thom and I anyway.

Nose striking throat: Sheesh, never considered that. CoroPlast looks better all the time.

Balor-English: Boy you are a reader if you found that detail buried in this tome. Glad you figured it out. Had to do with using commas or periods for decimals IIRC.



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Balor
recumbent guru

Russia
514 Posts

Posted - 10/23/2015 :  11:56:43  Show Profile  Reply with Quote
quote:
Originally posted by shooky56

Thanks Balor, you're welcome for my part of it and good luck.

It's funny about the foam behind the back/neck/nead. That's always been one of my thoughts too and have emailed my riding buddies about it often. Never thought about covering it in that stuff, actually had thought of using Kevlar epoxy sealed at the seams but left un-glued for the rest just to keep the foam a little more "together" during rear impact. But that topic needs a lot of research as to the best foam density etc. In recent months my thoughts on that topic have been more along the lines of commandeering an auto air-bag system... more study needed there too; only about a jillion details that can be goofed up. Can see the headlines "Man's airbag snaps neck from behind after crossing RR tracks!". But I digress.

Nose cone on an MBB: That one worries me, if you do this might I suggest you test it in the wind in a safe (traffic free) place?

It all sounds cool, you'll have to start your own build thread so we can "watch"! That's an interesting thing you bring up about fat hysteresis.


Well, I'll just go along with densest foam I can get my hands on, about 50 kgs/m3. In effect, it would turn my bike into kind of 'full body cycling helmet', good only for one major impact unfortunately, but again - better rebuild than regrow (because latter is not an option yet, especially when it comes to upper extremities like the head, lol).

As for fat hysteresis - here is a little monster of a thread at bentrider, I've learned quite a bit along the way as I've argued my point with sceptics:
http://www.bentrideronline.com/messageboard/showthread.php?t=122265
I am surprised that noone, to my knowledge, came up with this idea, and it neatly explains why MBB bikes are so much better at power delivery (hence, hill climbing). It also explains why some are much more affected by switching to bent than others - double check your BMI :)

This is me on my RWD, now sold for reasons mentioned above:
https://vk.com/photo127839343_377565301


This is my new, Zockra'ish MBB, with previous owner on top:
https://vk.com/photo127839343_387452233

I have no experience with welding at all, and do not intend to pick it up truth be told - composites and advanced polymers are the future :)
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Speedbiker
human power expert

USA
3760 Posts

Posted - 10/23/2015 :  12:16:58  Show Profile  Reply with Quote
Argued his point on BROL? I'm shocked. Good thing he found his way over here. Balor, this forum is where you will find logical discusses by many who actually design and race recumbents. Very happy you found us. You have some nice bikes. 300 watt FTP is very strong on a recumbent. Very few each that level. Good job.
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Balor
recumbent guru

Russia
514 Posts

Posted - 10/23/2015 :  12:33:39  Show Profile  Reply with Quote
quote:
Originally posted by Speedbiker

Argued his point on BROL? I'm shocked. Good thing he found his way over here. Balor, this forum is where you will find logical discusses by many who actually design and race recumbents. Very happy you found us. You have some nice bikes. 300 watt FTP is very strong on a recumbent. Very few each that level. Good job.



Well, my FTP on recumbent seems to be nearly 30% less and this is entire point of that thread :).

As for 'arguing on BROL', lol, right, experience does not equal being able to make correct assumptions, especially when it comes to things that are governed by 'motor memory' and not readily available for verbalization.
For instance, VERY few people that ride upright bikes are familliar with countersteering and would deny that they are doing it... yet they all do :)
You need to be an engineer with correct understanding of physics and scientific mindset... it is the same everywhere, be it BROL, MTBR or russian Velomania. While each person is unique, people are still pretty much same everywhere :).

Unfortunately, the MBB is too small for me and riding it for long periods leads to sharp knee pain, and it requires a lot of experience to manuever at speed (and it has aerodynamics of a refrigerator), so my average speed is not that good so far. But when it comes to climbing inclines, I could sprint up inclines with speed that is pretty much equal to my DF speed or perhaps even more (fridge or no fridge, it is still better than of an upright bike a bit), while on RWD I'll get out of breath, drown in lactic acid and had to slow down to a crawl halfway.
Weight of both bikes is about the same.

Sorry for thread derailment, back to the topic:
A smallish bug report: When I switch to metric units, rider designer input boxes stay imperial (inches).

Edited by - Balor on 10/23/2015 12:36:49
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Balor
recumbent guru

Russia
514 Posts

Posted - 10/23/2015 :  12:44:30  Show Profile  Reply with Quote
By the way, I see two alternatives to MBB when it comes to minimising 'hysteresistivity factor', but personally I'm not sure that it would work.
I you are interested in discussing it here, I can make a separate thread somewhere else.
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shooky56
recumbent guru

USA
545 Posts

Posted - 10/23/2015 :  13:31:57  Show Profile  Reply with Quote
Thread, probably a good idea as we're pretty far from the designer, although I'm more guilty of drift than most. Case in point: Pic#2 what is the memorial in the background? I'm a WW2 buff and assume it is something WW2?

Bug: Roger that, please report all that bother you.

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Speedbiker
human power expert

USA
3760 Posts

Posted - 10/23/2015 :  16:33:58  Show Profile  Reply with Quote
Combining Wayne's technique with Balor's needs you might end up with a Tetz type Zote foam body. Strips would be easy to shape and glue. I was witness to the safety qualities of this type of shell. I was riding in a liner behind Richard Myers' Zote foam liner when the hand of God picked him up and slammed him down on railroad stone beside the path. Richard survived with very minor injuries. Amazing. Maybe someone could direct Balor to the Tetz page(MARS?).
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shooky56
recumbent guru

USA
545 Posts

Posted - 10/23/2015 :  19:01:42  Show Profile  Reply with Quote
Not sure but think this will get you to most of it Baylor:

http://www.recumbents.com/mars/pages/proj/tetz/manual/0intro.html

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Speedbiker
human power expert

USA
3760 Posts

Posted - 10/23/2015 :  19:26:38  Show Profile  Reply with Quote
Wooo, it's all right there. I would do Shooky strips over a light frame. Richard and I discussed how you could sand the chines and stretch lycra over the thing. For Balor, a foam nose and tail, and a full lycra cover and he'd really be in business. Notice how Richard's Chiquita has a full lycra cover.
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shooky56
recumbent guru

USA
545 Posts

Posted - 10/24/2015 :  09:33:13  Show Profile  Reply with Quote
I've been on three side projects lately, only one relates to this thread. A friend from high school is now my doctor and could probably recite every TdF winner in order in the last 50 years. A funny incident occurred years back. Gary, my world class runner friend turned national class cyclist, found out about our "fast training group" and hooked up with us. Gary (a retired coach) still pulls 800w in our sprints even at 70 years old. Ten years ago after a hard ride in which Dr. Coulter had produced some exceptional sprints, Gary turned to him and said, "You know, you'd be pretty good if you trained.". We all got a big kick out of it. Russell has tried that training thing out in recent years and has buried all his personal records. It's a good thing for the rest of us he doesn't weigh 165 pounds.

So Dr. Coulter and I ran some tests today. The tests were coasting down a local hill. It was windy and getting windier all morning but we haven't had a calm day in weeks.

I'm not at all happy with the way I mounted it, as can be seen from the pictures but the goal was two-fold.

#1 Lower air drag.
#2 Warmer during the Winter and hopefully not too much of a steering load.

But it's pretty obvious it isn't mounted in a good place for air drag. Russell did say it was obvious that his chest and hands were well-protected.

But the coast tests were almost identical with and w/o the cone. The coast test consisted of approximately 1/4 mile and drops probably 40 or 50 feet. The wind was at Russell's back during the test and gained strength as the morning progressed. We ran three cone runs followed by two non-cone runs.

The times were almost identical with the non-cone falling between the best and worst cone time. The best cone time was about 1/2 second faster than the fastest non-cone time.

Riding back into the wind he actually was a little bit faster with the cone but, again, he used the cone while the return head winds were a bit lower so it's hard to say for sure.. He used the return trips, uphill and upwind, as "his workout" doing a coast out to the point he dropped below 20 mph (nearly a mile down the road). The cone coast average was slightly farther than the non-cone even though the non-cone benefited from stronger tail winds out in the open flat area of the test road.

Conclusion: It probably helps air drag slightly but it's mounted quite improperly. I plan to mount it more properly on one of my bikes so run some more test. I've also ordered some nichrome wire to make a defogger as I plan to make his keeper version with the top couple panels of Lexan as per Thom's suggestion for my nose cone. Just need to figure out how to adhere the wire to the Lexan. Considered just cranking up the current until the wire sort of melts into the Lexan. We'll see. Any suggestions?

Russell, unlike me, is an avid facebooker. He said he was asked about pictures, "Can't it's top secret.". lol.

[URL=http://s1372.photobucket.com/user/shooky56/media/Recumbent%20Postings/Upright%20Nose%20Cone%201_zpsamctrm1f.png.html]
[/URL]

[URL=http://s1372.photobucket.com/user/shooky56/media/Recumbent%20Postings/Upright%20Nose%20Cone%202_zps7qurpesl.png.html]
[/URL]
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Grant-53
recumbent guru

USA
544 Posts

Posted - 10/24/2015 :  10:18:00  Show Profile  Reply with Quote
The outer shell of the helmet or body serves to distribute forces and minimize puncture. Good seam bonding is important and several materials are suitable to be the skin. Polyurethane paints are great but be aware of the need for breathing equipment when using it.
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Grant-53
recumbent guru

USA
544 Posts

Posted - 10/24/2015 :  10:19:07  Show Profile  Reply with Quote
Shooky your results match mine closely.
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Balor
recumbent guru

Russia
514 Posts

Posted - 10/24/2015 :  10:41:19  Show Profile  Reply with Quote
quote:
Originally posted by shooky56

But it's pretty obvious it isn't mounted in a good place for air drag. Russell did say it was obvious that his chest and hands were well-protected.

But the coast tests were almost identical with and w/o the cone. The coast test consisted of approximately 1/4 mile and drops probably 40 or 50 feet. The wind was at Russell's back during the test and gained strength as the morning progressed. We ran three cone runs followed by two non-cone runs.




Small wonder - it channels air right into chest cavity. It should be taller, with smallish transparent windshield on top, I presume.
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Balor
recumbent guru

Russia
514 Posts

Posted - 10/24/2015 :  10:55:47  Show Profile  Reply with Quote
quote:
Originally posted by Speedbiker

Combining Wayne's technique with Balor's needs you might end up with a Tetz type Zote foam body. Strips would be easy to shape and glue. I was witness to the safety qualities of this type of shell. I was riding in a liner behind Richard Myers' Zote foam liner when the hand of God picked him up and slammed him down on railroad stone beside the path. Richard survived with very minor injuries. Amazing. Maybe someone could direct Balor to the Tetz page(MARS?).



I am already familiar with that, and I admire his work, but unfortunately I found nothing similar to zotefoam locally, and I suppose that styrofoam might work as well or better (if not with repeated strong impacts). And I am unsure whether polyuric coating would stick to it. I might try again, perhaps.

As for durability... I am much heavier than he is, 200 - 220 pounds. That means that my shell must be stronger (and heavier) as well.
But being heavy means less trouble from wind interference :).
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Balor
recumbent guru

Russia
514 Posts

Posted - 10/24/2015 :  11:11:32  Show Profile  Reply with Quote
quote:
Originally posted by shooky56

Thread, probably a good idea as we're pretty far from the designer, although I'm more guilty of drift than most. Case in point: Pic#2 what is the memorial in the background? I'm a WW2 buff and assume it is something WW2?

Bug: Roger that, please report all that bother you.





Likely it is. It is in "Velikiye Luki", at least that's what inscribed on it.
My town (Tver) is located on the border of a 'turning point' where Nazi were turned back, so there are a lot of war memorials here, one of those is almost literally in my back yard, heh.
Most noteable one is this:

http://wikimapia.org/1834018/The-Second-World-War-Memorial

By the way, here is Matthew Robert Blake (http://www.worldwidebikeride.com) enjoying local sights, you can see a part of this memorial there:
https://vk.com/albums127839343?z=photo127839343_376892586%2Fphotos127839343

Warmshowers.com in great idea, I hope I'll be using it someday as a guest - wanna travel in Europe on my velomobile on a rather limited budget :).

If any of you guys will be travelling in Russia any time soon, I can host you as well!

Edited by - Balor on 10/24/2015 11:12:33
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Balor
recumbent guru

Russia
514 Posts

Posted - 10/24/2015 :  11:28:32  Show Profile  Reply with Quote
Aaaaand back on topic again.
Might it be possible to add an option to export the model with just the turtledeck part of the canopy? It would improve aerodynamics a bit on case of open cockpit design and provide protection for the head in case of turnover.
Btw, if you have the time, I'd be much interested how big of an improvement this turtledeck would give as compared to just the head sticking out like a sore thumb and working as an airbrake?
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shooky56
recumbent guru

USA
545 Posts

Posted - 10/24/2015 :  13:17:26  Show Profile  Reply with Quote
Hope I can cover it all, several topics.

Memorial: Thank you.

Channels air: Yes that's what we thought also. If you.hmmm let me link up Mike. First Baylor, meet Mike Mowlett.

[URL=http://s1372.photobucket.com/user/shooky56/media/Recumbent%20Postings/Mike%20Mowlett%20Full%20Dress_zpsvvoq5jew.png.html]
[/URL]

Mike does a tireless and thankless job of keeping records for all the community including the sanctioned world records. Not only that, Mike is great athlete. At one race he ran onto the track out of the privy a lap down. Caught the peloton, pulled the entire race (an hour) and was outkicked. A guy running a camera showed 400w when pulling out of Mike's draft. Mike has also hit about 60 mph at Battle Mountain and isn't afraid to try anything for aero.

My intent was to mount the cone more like Mike's. It's a long story about the mount, we knew before we tested it was wrong but the test subject is a practicing MD and quite busy so we rushed.

Grant: We're not done yet!

Turtledeck: Did you see the canopy designer? Just click []Canopy and []Canopy Tugs on the shell design page.

Zote -> Styrofoam: Quite different actually, it's a shame you can't get it. Unless your shell is structural (modular frame and shell) I don't think there will be strength differences. I mean a little sure as the shell will be bigger and plow more air but not like a structural shell. Maybe that's your intent. After looking at that treatment Polyurea, I think I'm more impressed with just cloth (glass/carbon/kevlar) and epoxy but suite yourself, you're the guy doing it.

Off to punish ye olde carcass. Another 12,000 of these and the Gods of Pain won't have my body to kick around anymore.





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shooky56
recumbent guru

USA
545 Posts

Posted - 10/24/2015 :  13:24:23  Show Profile  Reply with Quote
One more thing. I'll post some pics later but, one thing mentioned was off that book review saying that you may as well bob-tail the tail fairing after the cross-section is 1/2 the maximum cross section (at least that's the way I interpreted it). At any rate, I ran a CFD for my new trike frame with a shell and then did nothing different except extend the two feet. At that stretch it appeared (no measurements, just eyeballed) that if I bob-tailed it at the old length, it would be about half. Actually it was about half width (although nearly the same height). Cross-section at the bob tail should be about half anyway.

The drag numbers (still working, it's been stabilizing for several hours now) are

.16 for the short standard tail.

.10 for the long tail

bob tail: I'll have to rig the software to export a bob tail to test in the CFD run. Might take a few days but it's an exciting result if it really works like that... we'll see.

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Balor
recumbent guru

Russia
514 Posts

Posted - 10/24/2015 :  14:03:25  Show Profile  Reply with Quote
So long as we are talking about Kamm tails and aerodynamics, we might as well add turbulators:

https://en.wikipedia.org/wiki/Turbulator
http://www.mh-aerotools.de/airfoils/turbulat.htm

By the way, this is one of my ideas for 'practical streamliner', and this an other reason why I want to make an outer shell of styrofoam - it can be easily dimpled, mostly for crosswind purposes, but I am planning a Kamm tail as well - so it can be reasonably short yet allow for cargo space at the back.

And yes, my frame would be structural, reinforced from inside to allow installation of wheels, seat, suspension and 'cargo hold'.
If you'll add a tug for Kamm tail cut-off, I'll be very grateful if you'll share it.

By the way, there is a nice Jaguar standing near my house (not mine, heh) - it sports a distinctive turbulator at the top.
Those things do work, heh.

Edited by - Balor on 10/24/2015 14:08:14
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shooky56
recumbent guru

USA
545 Posts

Posted - 10/24/2015 :  14:47:21  Show Profile  Reply with Quote
Structural: Gotcha.

Kamm Cut-off: If/when I get that working I'll publish it Baylor.

Dimples: Here's one discussion by the AeroVelo guys. https://www.youtube.com/watch?v=ZXpZy_A7mMk
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Speedbiker
human power expert

USA
3760 Posts

Posted - 10/24/2015 :  17:15:55  Show Profile  Reply with Quote
Remember, a kamm tail never helps you(except maybe in certain crosswinds). A kamm tail is just chopping off a body past the point of attached flow. If you shape your shell right it may be worth it to continue the shell all the way to a point at the back. Maybe add a little recurve to help with pressure recovery. Of course if your liner has to fit in the back of your truck, shape it right until it hits 8 feet, then chop it off. But don't say you did it for aerodynamic reasons.

Edited by - Speedbiker on 10/24/2015 17:19:12
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shooky56
recumbent guru

USA
545 Posts

Posted - 10/24/2015 :  18:34:16  Show Profile  Reply with Quote
Baylor: cm-in fixed. That was only in the rider designer right? It won't auto-swap the existing text box number when you check the radio button but will report the correct units for any new click. For instance if you click the ankle and see 15, then click "Metric", you won't see 38.1 until you click the ankle again. Not ready for a release yet.

Kamm: You can actually do that yourself for production. Just design long and chop it off. Because I'm running Cfd runs I have to export the mesh chopped off "in code". That's a lot harder.

Tests: Yes you are right and we were well aware of exactly that (Crr versus Cda) and, in fact, said that very thing. My comment to him was "It'd be a lot better test into the wind if the wind were steady.". He nodded as I spoke as he was well aware also. The problem with the headwind was it was building during the day and gusty with a few mph (8-11). 2 or 3 mph headwind difference between runs wouldn't give us anything worth reporting, not that we got anything anyway. The problem is the weather wasn't cooperative, Doc is always busy and we squeezed it in at his convenience.

Height: Totally agree and already designed one that came out about twice as tall (used Mike's pic as a guide). My original worry was wind loading but he said it was barely noticeable and the wind was horrible today.

Future Test: As far as a valid test, I'm going to mount it on my bike and do them myself so we don't have to coordinate and I can pick a calm day. He rides before sunrise most mornings at this time of year. But I understand what I need to do good tests, just need Mother Nature to cooperate.
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Joel DIckman
recumbent enthusiast

USA
129 Posts

Posted - 10/24/2015 :  18:43:07  Show Profile  Visit Joel DIckman's Homepage  Reply with Quote
quote:
Originally posted by shooky56

Hey Thom... Physics: You're dead right on that (no pun intended). Maybe when GM is making these, they can figure it out. As Joel's message says, "These three prevent most accidents: seeing, being seen, & (usually) common sense.". Our best air-bag is not getting hit in the first place. Tell you one thing, I went from being a no-mirror-a-tall guy to actually having a couple of attention getters forward (usually just bumps) because I'm tunnel visioned on my mirror.





"Our best air-bag is not getting hit in the first place." My thinking exactly. The kinetic energy difference between the motorist in his 5000 pound 200 horse power Sport Utility Vehicle and the cyclist in his 40 pound recumbent streamliner is enormous. So trying to design your streamliner out of impact absorbing material strikes me as hopeless. Anything massive enough to afford real protection in a collision with a motorist will make your human powered vehicle too heavy for practical use.

There are things you can do to mitigate risk though:

1) Good situational awareness is essential. Military people in combat always emphasize having your head on a swivel so you can continually scan your surroundings for threats. I think vulnerable road users like cyclists need to do the same thing. You cannot pivot your head on your neck and twist your entire upper body at the waist if you are in an extremely reclined position. A more heads-up seat angle will make this possible. Good mirrors help too. The best mirrors attach to your glasses or helmet and let you scan rearward by twisting your head.

Head canopies are great for racing, but are an accident waiting to happen for everyday street riding.

2) A super-low seat height - like the low racer bikes and low racer style trikes - will significantly restrict your field of vision to your safety detriment. Also makes you more subject to being hidden behind taller vehicles and thus harder to be seen by motorists. It is better to have a seat height similar to a sedan. Say roughly eighteen or nineteen inches off the ground. An extremely low seat height will also place you at greater risk of going under the wheels of an elevated-bumper SUV or pickup truck. This can spoil your whole day.

3) Continuous progress in LED and battery technology over recent years make flashing LED lights cheaper, more powerful, and more effective than ever. Combining active conspicuity measures such as LED flashers with passive measures like large areas of reflective tape on a fairing is the best way to compel distracted motorists to notice us and avoid collisions.

Like shooky56 says, the best protection is to avoid having the accident in the first place: prevention.

I am more optimistic about designing streamliners and velomobiles to reduce injuries in cases of rolling over or just falling on your side. A light weight roll bar attached to the back of your seat could help. Steve Delaire of Rotator built some long wheelbase bikes called Super Sevens that had frame tubes enclosing the rider front to back. I think these tubes served a dual purpose: providing attachment points for fairings, and also absorbing impact in a crash.

Safe riding,
Joel Dickman
http://lightningriders.com

These three prevent most accidents: seeing, being seen, & (usually) common sense.

Edited by - Joel DIckman on 10/25/2015 07:44:38
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Balor
recumbent guru

Russia
514 Posts

Posted - 10/25/2015 :  03:00:31  Show Profile  Reply with Quote
quote:
Originally posted by shooky56

Structural: Gotcha.

Kamm Cut-off: If/when I get that working I'll publish it Baylor.

Dimples: Here's one discussion by the AeroVelo guys. https://www.youtube.com/watch?v=ZXpZy_A7mMk




Thanks! I know that simply chopping off in production is easy, but if you intend to implement it anyway - it would surely be useful not just for me, but for future users of the program - in case they would want to design a practical, streetable streamliner, cause it has to incorporate Kamm tail due to size constrains.

As for aerovelo guys - yea, I've seen that video. Point is, they have carte blanche on length and size of the liner, it being a BM-only camera bike.
So they do not need to worry about cross winds, passing trucks and cargo space. I do.
Unfortunately, calculating proper turbulator placement and size seems to be a kind of black magic higher math that is certainly above much reach... I think I'll have to intuit it.

quote:
Originally posted by Joel DIckman
"Our best air-bag is not getting hit in the first place." My thinking exactly. The kinetic energy difference between the motorist in his 5000 pound 200 horse power Sport Utility Vehicle and the cyclist in his 40 pound recumbent streamliner is enormous. So trying to design your streamliner out of impact absorbing material strikes me as hopeless. Anything massive enough to afford real protection in a collision with a motorist will make your human powered vehicle too heavy for practical use.



Well, like I said, I was never intending to survive a head-on collision on a highway. It must withstand being rear-ended at moderate speeds, and provide cushioning due to a fall, rollover and slide at the very least.
As for seeing and being seen... unfortunately, it can help you only so much in case of drunk drivers, hot heads or outright psychopaths (I've seen some really scary reports). But this is a risk I am willing to take, especially if minimized.
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