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carolina
recumbent guru

USA
592 Posts

Posted - 10/02/2017 :  09:06:47  Show Profile  Visit carolina's Homepage  Reply with Quote
What speedbiker said: watch my youtube of my 2 wheeler low racer. Very hard to ride but you will have a terrible time getting it rolling like i did, was not very rewarding and a bit disappointed. And alot of time and money. There are 3 wheelers at battle mountain too. Iam a novice or maybe a amateur but these guys are pros. Better listen to them.

Only thing you will learn is: i wish i had listened.

I can get started slight down hill shakey, terrible funny on level ground and forget a slight uphill.
_______________
velosRus.com

Edited by - carolina on 10/02/2017 09:33:36
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Joel DIckman
recumbent enthusiast

USA
129 Posts

Posted - 10/02/2017 :  14:45:26  Show Profile  Visit Joel DIckman's Homepage  Reply with Quote
quote:
Originally posted by Speedbiker

You're in high school? Great job. Two areas to consider. Landing gear require special skills and are generally hateful. And low vehicles don't work well with foot flaps because your legs are too bent for good leverage. Secondly, big canopies cook you in summer sun. I can't suggest strongly enough that you consider a tadpole configuration three wheeled velomobiles.
Keep up the good work!



I agree with Thom (Speedbiker) about landing gear being a royal pain in the ass to construct and use, and that foot flaps or slits do not work well with very low recumbents. Also agree about the big transparent canopies. They have the extremely high koolosity factor. But if you actually ride inside a vehicle built this way on a warm day (like the Go-One velomobile) you will quickly discover what a strip of bacon feels like while being fried.

I have butted heads with Thom in the past about the practicality of two wheeled streamliners versus three wheelers. I continue to see this issue very differently from him. The first thing any prospective builder (or rider) should do is get some real-world saddle time in on a variety of recumbent bikes and trikes. Bikes and trikes are totally different animals. Some people just love the go-kart quality of trikes, and do not like balancing on two wheels. Other people love the leaning-into-the-turns quality of bikes, and hate riding trikes. (Some riders like both.) Before investing lots of time and money building something, you should discover what kind of rider YOU are. Only personal riding experience can reveal this. You can't discover what you like and do not like through pure cogitation.

I agree with Thom that a very low and laid-back recumbent bike (essentially a low racer) enclosed in a hard streamliner shell is very challenging to balance and ride. Not a practical vehicle for street riding. But a two wheeler need not have this format. The Lightning F40 has a significantly higher and more erect seating position, together with Spandex middle and tail fairings. The flexible Spandex middle section is of major importance to making the bike manageable when gusting side winds become very strong and intermittent. The higher and more upright seat, together with the flexible middle section lets the rider use body English to balance the bike in gusting side winds. Being higher up gives you more time to make balance corrections, and being more upright inside the Spandex middle gives you both the wiggle ability and wiggle room to shift body weight in response to changing winds. This is highly difficult to do in a very low and very laid-back racing recumbent enclosed in a tight-fitting hard shell fairing.

You do have to learn to balance an F40-style bike when going at high speed in gusting winds. You cannot reasonably expect to just get the hang of it immediately. However, I think that Thom exaggerates the level of difficulty involved in doing this. It is not beyond the ability of a large number of cyclists, and really is far easier than piloting the lower and more laid-back streamliners used at HPRA races.

Granted, a trike or velomobile is easiest of all. You just hop on and ride, with very little learning curve. Riders gradually learn the limits of turning sharply without tipping over through trial and error. The low learning curve of trikes (and velos) is likely their single most important appeal, especially to middle aged and older people. Many cyclists - even experienced and accomplished ones - are intimidated by the prospect of learning a new skill. This includes some people who will not admit it.

But the F40 (and similar bikes, like Richard Myers' Banana Bike) is much lighter, faster (except perhaps on a very flat and straight course), cheaper, and easier to store and transport. The fairing - or parts of the fairing - can be removed from the bike pretty easily to adapt to different wind conditions, the whim of the rider, or to do maintenance. And most of all, it is far more fun to ride, at least for those of us who love leaning into turns.

Now at this point in the discussion somebody (maybe Thom) will say "If the Lightning F40 is so great, why have so few of them been sold over the past twenty five years?" I do not have a good answer to this question. I think the F40 deserves to be much more popular than it is. Yeah, I know... my thoughts about this together with $5 will buy you a Happy Meal at McDonald's.

I do not think the main problem is that an F40-type bike is too hard to ride for the more enthusiastic cyclists who put in big miles and are willing to buy expensive machines.

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

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

Edited by - Joel DIckman on 10/04/2017 10:16:22
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Speedbiker
human power expert

USA
3755 Posts

Posted - 10/04/2017 :  10:53:12  Show Profile  Reply with Quote
Joel, your post is spot on. I advised Matthew to research the F-40, the Chiquita, and Rick's coroliner. These are in my opinion the most practical two wheel liners(without muddying the water). When Matthew understands the characteristics that make them work he'll be on his way.
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Jeff Wills
human power supergeek

USA
1271 Posts

Posted - 10/04/2017 :  19:42:52  Show Profile  Reply with Quote
Matthew, I have given up on my streamliner project for many of the same reasons that Joel and Thom have mentioned. While I was able to successfully start and stop on its landing gear, that was on a closed track. I'm not sure I would be able to handle this on an open road.

For an example of a "roadable" two-wheel 'liner, I'd look at John Tetz's Orange Foamshell:
http://www.recumbents.com/mars/pages/proj/tetz/OFS/projtetzOFS.html


__________________
Jeff Wills
All my bikes:
(Site nuked by Comcast. Will return soon.)
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Matthew Martin
Starting Member

USA
24 Posts

Posted - 10/04/2017 :  20:06:26  Show Profile  Reply with Quote
Thanks for the interest, I have taken this into account and am most likely going to have Bombay doors or just foot holes with no covering at all. I will still add the 2 landing gears for parking the bike. I still want 2 because I just know that some kid at my school may try to touch it and may tip it, if it only has one landing gear.
New renders with mirror and a little sun protection. I also raised the seat to 40 Degrees. The canopy will come off (midsection between the black and red lines).



Edited by - Matthew Martin on 10/04/2017 20:26:19
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Jerry
recumbent guru

USA
981 Posts

Posted - 10/04/2017 :  21:21:19  Show Profile  Reply with Quote
That looks great! If you build it, make sure to have a granny gear of around 18-20 inch gear for starting. A Battle Mountain or HPV racing streamliner might not need it, but a liner for open roads and streets does imho. A rigid body streamliner can feel like you are trying to start uphill. Maybe not after you get acclimated to it, but starting out new you will need it.
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Speedy
recumbent guru

USA
882 Posts

Posted - 10/04/2017 :  22:56:35  Show Profile  Reply with Quote
Matthew ... your computer renderings are quite good. Thumbs up !
It looks slippery and fast for a race track.

If you would allow a few honest tips from someone who has built some streetable streamliners.

For street use the physics of the shape you have shown will undoubtedly be a dangerous handful.
When designing a streamlined shape the designer needs to consider :
Where is the center of aero pressure, center of mass, and axle weights ?
The best balanced bike will have all three centers fall right about where the riders belly button is.
The configuration shown will have too much weight on the front wheel and the center of pressure too far forward. A slight cross breeze will blow it out of control.
A long wheelbase where the wheels are on either end of the shape is far more stable in windy conditions.
Because of the side winds I found it's best to have a fairly upright seat back to gain leverage against nature's forces and improve control.
Roads have varying degrees of crown for water drainage which complicates the design for landing gear.
Foot doors expose the Achilles tendon to injury. When coming to a stop the foot hits an unexpected "something" yet the bike keeps moving slicing the back of the leg.
Note the side doors on the attached picture.
My experience is to have the seat low enough so you can touch the ground with a hand by reaching out the side door.
Shape is more important then surface finish. Don't worry about exact fit for the windshield.
Accuracy of alignment, wheels tracking straight is super important.
Please ... don't let my words discourage you from building but do consider the wisdom of experience.
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Matthew Martin
Starting Member

USA
24 Posts

Posted - 10/05/2017 :  16:14:43  Show Profile  Reply with Quote
I do not think advise should ever discourage someone, so thank you for the advice. I completely looked over the the surface pressure for the shape, so thanks for pointing that out. I got to caught up with the drag coefficient. If you do not mind me asking, I would like to know how were were able to roughly determine where the center of pressure was, and if making it have a more rounder nose would help bring back the center of pressure. I have access to Auto desk Flow design and was wondering if anyone knew how to check the surface pressures. I know the program has a pressure mode but I do not know what the optimal surface pressure would look like in the program.

This was The surface pressures of the bike in Flow Design. What would optimal look like? More blue or more red?
And the original render did have too much weight on the front wheel but now I moved it up 15cm which made a big difference in the weight distribution

The red areas are just vacant areas in the fairing. I know putting anything in the front section would mess up the handling.
The blue thing is my skate board which fits inside the fairing.

Once again, Thanks for the advice...the more the better!

Edited by - Matthew Martin on 10/05/2017 18:01:13
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warren
human power expert

USA
6114 Posts

Posted - 10/06/2017 :  09:30:33  Show Profile  Visit warren's Homepage  Reply with Quote
As a rough estimate you can use the total side area of the fairing and ensure that the center of that area falls around the rider's center.

In general a rounder nose is better for handling side winds and a pointier nose is better aerodynamically.
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Speedy
recumbent guru

USA
882 Posts

Posted - 10/06/2017 :  10:23:39  Show Profile  Reply with Quote
The more refined and efficient the shape is the further back the center of pressure will be. For the most refined shape 60% back from the nose would be expected. 25 ~ 30% from the nose for a basic or turbulent condition.
A double edged sword as the the most efficient shapes are the most sensitive to cross wind conditions. The sensitivity is caused by the center of pressure moving forward and backwards depending on the angle the wind is coming from.
Not a good thing in street conditions as the wind swirls off buildings and passing traffic. This is the reason the typical racing streamliners don't adapt to street use.
The strategy I used to brace against these conditions was to put the wheels at each end of the shape so when the center of pressure moves it's still between the wheels.
Pushing the human as far forward in the shape as possible with a long tail helps to balance the bike.
Human balance system, the inner ear, is designed to be upright. A fairly upright seat angle helps to feel the balance in windy conditions.
When the design is wrong (which I have done) it feels like the hand of god reaches down and tosses you about.
First time out ... Expect the unexpected.

Edited by - Speedy on 10/06/2017 11:28:10
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warren
human power expert

USA
6114 Posts

Posted - 10/06/2017 :  11:06:38  Show Profile  Visit warren's Homepage  Reply with Quote
Among his other accomplishments, Steve (Speedy) rode an aluminum shelled streamliner from California to Indianapolis to participate in an IHPVA championship event. I think that taught him a lot about what makes a 'liner practical.
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Jerry
recumbent guru

USA
981 Posts

Posted - 10/06/2017 :  21:11:34  Show Profile  Reply with Quote
Yes, and the Coyote was a pretty bad ass ride too. Mr. Wizard down here in Dallas stills has one of the two built. Great job Steve.
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alevand
human power expert

USA
2929 Posts

Posted - 10/07/2017 :  11:26:10  Show Profile  Visit alevand's Homepage  Reply with Quote
Ive always had long wheel base bikes. The two problems with a full fairing on lwb are: 1, The fairing has to be longer to cover the front wheel. This moves the center of pressure foreword (since were talking cp) and increases the size of the fairing, so theres more side force in the front, where there is little weight. So you want to keep the nose as small as possible. Having the front wheel outside the fairing helps alot, but is less aero, thus slower, except in cross winds, where it can tolerate more wind before being blown off the road. This would be about the same size fairing as a swb, but with a wheel in front of it. The second is maneuverability. Having a nose over the front wheel limits steering to a maximum of about 45 degrees total ( +/- 23 deg), with a big opening at the bottom. 4 lanes are needed for a u-turn. Ive never ridden a swb fully faired bike , so I cant really comment.

Remember what happed to Dave Johnson in the Great White, when a pickup truck passed.

Crashing in the Coyote on Texas chip seal, id like to have some coro on the sides.

C:
Tony Levand

Edited by - alevand on 10/07/2017 11:30:52
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Speedy
recumbent guru

USA
882 Posts

Posted - 10/07/2017 :  19:48:40  Show Profile  Reply with Quote
Actually ... the aluminum cross country bike had a 13 foot turning circle.
With "streetable" being a design goal there was 14 steering and linkage experiments completed before designing the body. Several of my long wheelbase designs had fairing pieces that mounted to the fork and still maintain a full enclosed shape.
Super 7 and Interceptor being the best sorted, most street functional bikes.
The Coyote was originally a race bike that "Dog Boy" Dean Peterson adapted to the street use. He rode it extensively around town, club rides, centuries and won the world championship in Las Vegas 1996.
It was my first foam core construction monocoque. 45 pounds. Hugely sturdy and which probably saved Dog Boy's life when the brakes failed descending into Anza Borrego desert.
The body was scratched but usable.

NOTE TO MATTHEW !
Do not use rim brakes in a streamliner. The rims overheat and blows the tires off.
Use only cable operated disc brakes with oversized discs.

Mr. Wizards (Doug Davis) had me build his Coyote for velodrome use. It is nomex core construction. 10 pound lighter bike but probably would not have survived the same crash.

Second note to Matthew
For a completed bike target 50 pounds or lighter. Under 40 is ideal.
My Interceptor was 28 pounds.

Edited by - Speedy on 10/07/2017 19:49:34
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alevand
human power expert

USA
2929 Posts

Posted - 10/07/2017 :  20:32:22  Show Profile  Visit alevand's Homepage  Reply with Quote
Mounting a steerable fairing on the fork is a bad idea, too unstable in the wind, it should be fixed to the frame. 40 lbs is a good weight, that's my goal on the next bike. Ive never had a blow out using v-brakes in over 20k miles, but I live in flatland, no mountains.

C:
Tony Levand
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Matthew Martin
Starting Member

USA
24 Posts

Posted - 10/07/2017 :  21:40:29  Show Profile  Reply with Quote
I worked on the design a little bit and it turn out that a lwb platform would fit into the modeled fairing, without having to make it longer. I also made the nose more blunt.


Thanks for the feedback

And I do not live in mountainous terrain, no mountains in Florida, So to start I will have rim brakes which are included in the group set that I plan in using, I do want to upgrade to disk brakes though.


A few posts back Mr. Warren mentions an aluminum streamliner...Does anyone have any photos of the bike. I would be really interested in seeing it
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alevand
human power expert

USA
2929 Posts

Posted - 10/08/2017 :  07:01:22  Show Profile  Visit alevand's Homepage  Reply with Quote
Nice CAD. You might want to take into account the Florida sun and the greenhouse effect of the large windscreen. It will be like pedaling inside a car with the windows rolled up and no ac. Even without the sun an enclosed bike will be 10 degrees warmer inside and near 100% humidity, due to sweating and breathing, so you might want to make it a convertible top. Electric or solar powered fans, blowing in cool outside air when stopped might make it bearable in hot weather. Im not trying to be negative, just something to keep in mind in your design.

C:
Tony Levand
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Matthew Martin
Starting Member

USA
24 Posts

Posted - 10/08/2017 :  07:17:35  Show Profile  Reply with Quote
Yes, you are absolutely right...If you look on the model between the black and orange lines, I am planing to make that mid section removable. I a also researching mini ac solutions that require no ice, The bike will probably end up with a 12v power supply to run the lights and whatever I choose to do for ac.I am also planning to make tinted screens, that I can put on when it is sunny out.
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warren
human power expert

USA
6114 Posts

Posted - 10/08/2017 :  08:35:54  Show Profile  Visit warren's Homepage  Reply with Quote
Looks great!
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Speedy
recumbent guru

USA
882 Posts

Posted - 10/08/2017 :  11:42:37  Show Profile  Reply with Quote
Matthew, the aluminum cross country bike was built in a time before the internet (1984) so it's doubtful there are any public photos. The trip was featured in several publications including the HPV Newsletter so there may be a way to dig it up. That bike ended up with 55,000 miles before being retired. Construction technique was typical light aircraft with .025" sheets riveted to bulkheads. There was some internal welded tubing frame structure. Designed and built in 6 weeks. It started at 65 pounds and was modified many times to a final weight of 50 pounds. Way too noisy, the local bike club name it "Rolling Thunder".

There were 9 copies of the Super 7 produced. Can't say for sure how many miles I rode on the 7's other then it was way more then the cross country. The only known wind blow overs that happened with that bike was at the Portland raceway when a small twister touched down. The twister took out several bikes including 2 Super 7's.

Easy Racer with Zipper fairing is a well proven example on a fork mounted fairing.

Interceptor got the most miles.
Here is a link to a Interceptor picture with fork mounted fairing.
Picture is a bit misleading as the full body is not shown.
http://www.bentrideronline.com/?p=594
The Interceptor was less streamlined so not the fastest of the designs.
Better serviceability was a design goal with the Interceptor. Enclosed wheels and drive complicate routine maintenance. The bottom half of the wheels were left outside the shape improving flat repair and brake cooling.

Brakes ... triple whammy
1) When the bike is more streamlined there is less drag (obviously) so it doesn't slow down when you stop pedaling which ... puts more load on the brakes.
2) With the wheel inside the body the rim gets less cooling, heat builds quickly.
3) Bike is heavier ... puts more load on the brakes.
You might get by with rim brakes in Florida but the risk of a failure is higher.
Be sure to leave enough rim exposed for cooling and check pad and rim wear often.


Edited by - Speedy on 10/08/2017 15:34:08
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Matthew Martin
Starting Member

USA
24 Posts

Posted - 10/08/2017 :  18:26:40  Show Profile  Reply with Quote
Yes... The rim brakes would just be a temporary solution until I recover from the cost of the bike. On the topic of cost, what does the average streamliner cost to build? I plan on using fiberglass so the 50 lb weight range is probably not an option. What could be an expected weight for a fiberglass streamliner with steal frame?
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alevand
human power expert

USA
2929 Posts

Posted - 10/08/2017 :  19:58:09  Show Profile  Visit alevand's Homepage  Reply with Quote
60-70 lbs

I use a 700x32c rear tire with a double wall rim (Salsa Delgado, 515 grams) and never had a problem with heating it. It more apt to pop if you leave out in the sun on a hot day. If you are concerned, get a deep V rim, it can sink a lot of heat. The rim and tire still have a tangential velocity inside the shell equal to the forward speed, so there is cooling. On the outside, the air is moving faster than free stream around the fairing.

If I brake from 30 mph to zero and assume all the kinetic energy is covered to heat in the rear rim, I weigh 140 lbs and bike weighs 50 lbs, thats 86 kg at 13 m/s = 7.6 kJ of heat. 6061 is .869 J/g K specific heat. Temperature rise in the rim is 17C. The air in the tire is heated by the rim and ambient temps by the tire, so lets say its average, 8c temperature rise for tire air. For adiabatic (300K) pressure rise would be ((300+8)/300)^k-1 or a 3% increase in pressure. For flatlanders this is no problem.

During ROAM some velomobiles used parachutes to control speed descending mountains, otherwise the front disks would overheat. Of course a fairing is totally useless in mountains, or big hills, as you have to lug the weight uphill and brake slowly down as not to burn the brakes or over speed. I think an aero brake would be a good idea. On tour, I usually keep the speed less than 35 mph on descents, and more like 25 unless the road is straight and no wind and near the bottom, then I let the brake go.

(http://hyperphysics.phy-astr.gsu.edu/hbase/thermo/adiab.html)


C:
Tony Levand

Edited by - alevand on 10/09/2017 06:24:38
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warren
human power expert

USA
6114 Posts

Posted - 10/08/2017 :  20:18:15  Show Profile  Visit warren's Homepage  Reply with Quote
Grant Connor writes (in an email)

"The sailplanes have a similar fuselage and canopy configuration as the shell Matthew Martin is designing. Internal air flow and solar heating issues are very similar. There are products to spray on the canopy to reduce solar gain. Air intake may be at joint of the canopy and shell.
Two extractor systems are being tried, Jonkers and Mandl."

Edited by - warren on 10/09/2017 09:06:32
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Speedy
recumbent guru

USA
882 Posts

Posted - 10/10/2017 :  14:58:50  Show Profile  Reply with Quote
The idea of building a streamliner is to improve efficiency and speed.
Streamliners are slope finders.
Any small slope either up or down can be felt in pedal pressure.
With that in mind, keeping it light so it accelerates and climbs well is important.
Maximizing speed on the down slope builds momentum to attack the next up slope.
Before the streamliner chapter of life I raced off road motorcycles.
High speed downhills never scared me. 60 mph was routine.
Other then the scare of bad brakes at the bottom of the hill.

The Super 7 design was built from .035" thin wall cro/moly steel tubing with a predominantly 2 layer fiberglass body.
Typical weight was 38 ~ 45 pounds depending on how is was to be used.
Here is a link to one example :
https://jnyyz.wordpress.com/2013/09/11/bm2013-wednesday-pm-results/
Sven was an intern for my bike business and was in high school when he built this one.
He did the frame and body fabrication at my shop (with my help) and the final assembly at home in his bedroom.
Never forget the accomplished smile he had when student beat the master at the Ukiah races July 1994. :-)

Edited by - Speedy on 10/10/2017 16:13:32
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alevand
human power expert

USA
2929 Posts

Posted - 10/10/2017 :  16:19:23  Show Profile  Visit alevand's Homepage  Reply with Quote
Super 7 is like my 2009 Carp: Amazing super 7 weighed only 40 lbs , with disk brakes and a 2 stage drive. Carp was 49 lbs dry, it was a monotube frame, 2.38 dia x .049. 451x28C front, 700x28c rear, one chain.

My brother use to race motocross dirt bikes, 250 cc. I would not want to fly through the air like that!
On your trip across the country, you had a loaded bike, how fast did you go down hills, on unknown curvy roads, buffeted by winds, hundreds of miles from home? Would yo go that fast now that you are older?

How good were the disk brakes Super 7? Seems there is no air flowing around a disk brake. I use to smoke the v-brakes regularly. https://www.youtube.com/watch?v=2S1KoZnIjbg




C:
Tony Levand

Edited by - alevand on 10/10/2017 17:34:04
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