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Virgin Kinetic Sculpture Racer

Posted: 23 Jan 2011, 9:10 am
by crazydave757
This will be my first year in the Baltimore Kinetic Sculpture Race and I'm excited about building my first entry for the event. I’m confident that I can build a suitable vehicle as I have 17 years experience as a participant in the Connecticut River Raft Race. I've built multiple human powered rafts all of which utilize pedal powered propellers. My experience as a raft racer will allow me great success in the water crossing segment of the sculpture race as I have lots of expertise on propelling large floating objects. The drive systems I use are built from salvaged bicycle parts. The pedal stations are linked to propellers via drive shafts, couplers, bevel gears, idler wheels, guides, and include safety guards for crew protection.

My largest raft is 24 feet long by 8 feet wide and is driven by four people who all pedal in a recumbent position. The main hull construction is of Lauan plywood covered in fiberglass and epoxy resin. Accoutrements include such items as a bamboo Tiki hut, a sonic effects panel with homemade clothes-pin switches (these activate multiple sounding devices), and an anatomically correct tiller handle to steer the “Little Willie” raft. ... illie.html

My inexperience lies in construction & configuration for a land based vehicle and it is this subject where I’d appreciate some direction and advice. I seek guidance on what would be considered the most reliable vehicle configuration in regards to wheel placement, wheel size, safety, and stability. My current plans include a three person crew, two of which have strong bicycling experience and are physically powerful riders; the third crewmember will go along for the ride as a barnacle and run the decorated kinetics apparatus that will be comprised of noisemaking accoutrements.I would be grateful for any suggestions and advice that a seasoned Kinetinaut could provide. I’m sure there is much to be gained from the knowledge and experience from experienced pilots.

Re: Virgin Kinetic Sculpture Racer

Posted: 23 Jan 2011, 11:53 pm
by Elliot
Wow Dave, that’s one hecka boat! You are obviously well qualified for Kinetics.

Let’s see… you are looking for “…the most reliable vehicle configuration in regards to wheel placement, wheel size, safety, and stability.” In this question, I interpret “reliable” as meaning proven design.

As for wheel placement, first we have to decide on the number of wheels. My suggestion is three. We are a lot more accustomed to seeing vehicles with four wheels (a few hundred million automobiles just in the USA!), so it is natural to begin thinking in those terms. But a four wheeled vehicle requires suspension, and accurate steering geometry, and it will still have much more rolling resistance than three wheels.

Now we can decide placement of those three wheels. Should the single wheel be in the front or in the back? (Presumably it will be the wheel that does the steering.) Both layouts work fine. At higher speeds you would not want to steer in the back, but it is fine for KSR. The choice is more about weight distribution and traction. (And of course, artistic considerations.) I have not seen the Baltimore course, but in all the west coast races the most difficult part is getting out of the water. The water exit will necessarily be uphill, so if any part of the vehicle other than a drive wheel strikes land first, you will be trying to push the vehicle uphill with the water drive. With your propeller experience you might make that work, but in most cases it will not. So my rule of thumb is that we need front wheel drive. (Actually, we need all-wheel-drive, but you have only two Pilots.) Now we have your two Pilots up front, each driving one front wheel, and the third wheel in the back, just steering.

As for weight distribution, you will need to find a happy medium. You need enough weight on those front wheels to have good traction for climbing up a slippery boat ramp, and the same with climbing a sand dune. But you must not be so front-heavy that you “nose over” when you apply the brakes on a down-hill.

Oh… I said “…each driving one front wheel…”. This is much better than running the two power paths together and then splitting them again with a differential.

Next, wheel size. In diameter, larger is always better. There are Racing Sculptures with wheels as tall as eight feet. Let me tell you, such wheels just laugh at things like street curbs and railroad tracks! Granted, there are a few successful entries with ATV tires, but those are exceptions. I cannot recommend anything shorter than two feet diameter.
Wheel width is tricky. You want them wide for sand. But in the mud, wide wheels tend to push the mud in front of them, so there you may want skinny wheels that cut thru to the bottom. It is quite common to carry “sand tires” that strap onto the wheels for sand travel (think snow shoes), and I have had some success with mud cleats that strap on somewhat like snow chains on a car.

Safety. Well, gosh, haven’t you heard – Safety Third!
The greatest hazard I can think of is an enclosed body that tips over in the water, so the occupants drown. Use common sense here.
Second, I think drive chains. Clothing can get caught and pull the wearer into the chain. A moving chain and sprocket can cut a hand off. So again, common sense all the way.

Finally, you asked about stability. Well, a three-wheeler is never going to be as stable as a four-wheeler. But keep the center of gravity low, and the track width of the pair of wheels wide, and you’ll be fine.

I have long thought that the ideal Racing Sculpture would have three wheels and three Pilots – each driving one wheel. But enough for now!

Re: Virgin Kinetic Sculpture Racer

Posted: 29 Jan 2011, 6:34 am
by crazydave757

Thanks for all the info that you provided. I've been doing lots of research trying to determine most likely build scenario based on your ideas. I find myself focusing on the all wheel drive suggestion you made. I've seen the pictures on the Baltimore Kinetic Sculpture Race website of the "Candy Haus" entry. Their all wheel drive seems the most logical and easiest construction method; at least as far as using the rear-drive half of a bike is concerned. I was wondering if you have access to any close-up pictures of the attachment method used to secure the bike frames especially on the front end of the "Candy Haus" where it appears the steering is also going on. I'd be interested in seeing the details of how the bikes are attached and how the steering functions.


Re: Virgin Kinetic Sculpture Racer

Posted: 29 Jan 2011, 4:43 pm
by Elliot
Sure enough, that Candy Haus is one fine sculpture! But all I know about it is what I see in the pictures on the web site. That includes pictures on Flickr, which you can access by going to the Links page. Among Neoflicks' pictures is one that shows Candy Haus from head on, in motion, and it looks to me like it was lucky to make it thru the race; there is a lot of flexing and bending going on with the front bicycles.

The design is simple enough. There must be a rectangular frame under the house, with the lengthwise pieces extending for the bicycles to mount to. All four bicycles have been cut off behind the steering head, and tilted 90 degrees. The rear bicycles are attached to the frame rails with various brackets and braces. This can be quite sound.

At the front, the bicycles have to be able to turn, and that means no cross bracing below the pivot point. This is iffier. Look at that head-on photo by Neoflicks again, and notice that the right front bicycle is trying to break away. Look at the obvious sideways force on the tire where it touches the ground. And the two front wheels do not appear to be traveling in quite the same direction. I take my hat off to the Candy Haus team for building this well enough to last the race! I bet they were careful not to make any sharp turns -- good job guys!

Now, the actual mounting of the front bicycles. Although I cannot see the details, I believe they used the steering heads that came off the same bicycles, complete with the forks and handlebars. The steering heads were welded to the tips of the main frame rails, in the normal orientation, just higher off the ground. Then the bicycles (tilted on end, remember) were welded to their own old forks.
Put another way, the front end of the bike was cut off, turned 90 degrees, and welded back on -- but this time the fork is attached to the bike frame instead of the steering head being attached to the bike frame. Then this unit was tilted up and the steering head welded to the main frame.
Finally, the two sides were connected to each other with steering arms and a long tie rod, just like on an old automobile. You can easily see the tie rod across the front of the vehicle. (Looks like it was spliced together out of several pieces.)

From what I can see in the pictures, that must be how it was done. Those guys did a great job achieving all wheel drive, and in a simple way! But I bet they had a ton of rolling resistance from the two front wheels fighting each other. I assume they started with correct steering geometry , but as soon as one of the front bikes flexes sideways, that geometry goes out the window.

I might consider reducing this design to three wheels, achieving "my ideal" layout. But I would use a motorcycle steering head and fork, to help withstand the tremendous sideways forces. Still, there is the issue of bicycle wheels, which easily collapse from sideways forces.

Hope this helps a little!

Re: Virgin Kinetic Sculpture Racer

Posted: 08 Feb 2011, 10:28 pm
by crazydave757
I'm curious as to what exactly the water portion of the Baltimore Kinetic Racecourse includes. I know there is a water entry & exit. Do you know how much water distance is covered? Does the water section require navigation around markers?

Re: Virgin Kinetic Sculpture Racer

Posted: 09 Feb 2011, 2:37 pm
by Elliot
Well, there is a map of the race course on the web site, under Spectator Guide. But for the water, it only says Water Loop. So we need an experienced Baltimore racer, or webmaster Tom himself, to fill us in.

Re: Virgin Kinetic Sculpture Racer

Posted: 10 Feb 2011, 11:22 am
by Chprnk
If it is the same as previous years, its simply going around the dock at the canton waterfront. should be centered on the dock. You enter from the east side, head out and then make a quick right around the dock and back to land. Have fear, its the baltimore harbor and plenty of depth to capsize whatever way you want to, and you need to be decontaminated if you touch the water!:)

Re: Virgin Kinetic Sculpture Racer

Posted: 10 Feb 2011, 5:44 pm
by Tom
Indeed--the minimal water loop merely goes around the pier, although this has proven difficult for many a sculpture over the years! I understand there is likely to be an extension to the water route added in the future, required for ACE sculptures and optional for non-ACE sculptures.

Re: Virgin Kinetic Sculpture Racer

Posted: 10 Feb 2011, 5:58 pm
by crazydave757
It sounds like the water portion of the race is quite short and as such does not require a bulletproof floatation device. I’m now planning to recycle a previously build Louisiana pirogue which I created for a cardboard boat regatta. The entire boat is basically a flat bottom canoe type vessel of the variety typically used for shrimping, clamming, and crayfish harvesting in the muddy backwaters of the Southern states. It’s built from cardboard, white glue and has been smothered with a very obnoxious lime green latex paintjob. Although the pirogue is water soluble it will not have sufficient time in the water to dissolve and fall apart. I’ll cover it with clear plastic condom to enhance the likelihood of its survival on the long journey to the water should it be a rainy day.

Re: Virgin Kinetic Sculpture Racer

Posted: 10 Feb 2011, 6:07 pm
by Tom
For the 2010 racecourse, a well-engineered sculpture could spend as little as 10 minutes in the water, although that could be 15, 20, or 30 if traffic congestion or problems arise. One of the more extreme cases was in 2004 when Cirque de Sore Legs was blown off course, broke apart, and was towed back by kayaks. You wouldn't want your sculpture to disintegrate if exposed to water for too long! Photos are at

Re: Virgin Kinetic Sculpture Racer

Posted: 11 Feb 2011, 3:07 pm
by Elliot
...does not require a bulletproof floatation device.
Dave, I respectfully disagree, on principle. I've seen plenty of failures on water in the various West Coast races, and they mostly happen immediately after entering the water. It appears to me that many basically sound boats fail when exposed to the additional -- and unpredictable -- forces imposed by all the land-going equipment, pedal-drive systems and whatnot.

We know from the photo of Little Willie that you are a skilled designer and fabricator, so I may be wrong in your case. But many raw beginners will be reading this information as the Forum grows, so I would like to suggest that any amphibious vehicle ought to have "bulletproof" floatation, no matter how short the water segment of the race.

Re: Virgin Kinetic Sculpture Racer

Posted: 11 Feb 2011, 10:24 pm
by crazydave757

Since beginners will be reading this information I would have to agree with your statement that “an amphibious vehicle ought to have "bulletproof" floatation, no matter how short the water segment of the race.” Safety should always be the top priority for all participants and all organizers as this creates the right environment for a safe and enjoyable event for all involved. I will add this though, if a component is properly engineered and constructed and takes into account the structural limits and inherent material restrictions a person could build just about anything they want out of whatever materials they choose. This is true provided the expected performance parameters are within the capability of the assembly.

My idea to use a cardboard Louisiana pirogue would not have included using it as a stressed member from which other components were mounted; rather it would be carried like cargo in a sling of bungee cords and foam. Then if it survived the journey to the water, it would be oriented appropriately for its floatation function. As you mentioned the journey to the water could present conditions unfavorable to a cardboard based floatation device and some damage may be sustained. I would definitely skip the water portion of the racecourse if my float device was compromised in any way. I was also envisioning supplemental floatation in the form of two outriggers which I made from two sealed cardboard Sono-tubes. These would be deployed and positioned to provide increased balance and stability while the vehicle is on the water. One of my main objectives for floatation is light weight so it’s easy to carry and navigate the racecourse.

Based on my measurements and calculations the combined weight of the cardboard pirogue and two outriggers is about 20 pounds and this combination would provide the vehicle with approximately 35 cubic feet of floatation. Since each cubic feet displaces 7.48 gallons of water at 8.35 pounds per gallon I’d be providing: 35 x 7.48 x 8.35 = 2,186 LBS of floatation for our vehicle. Our crew weight of three is 586LBS and our weight limit for our kinetic sculpture is 500 LBS. This would leave 1100 LBS of reserve floatation.

Incidentally, the cardboard pirogue I built was the only boat to survive the cardboard boat race in 2006 and it’s still in great condition, so this isn't your typical cardboard pirogue. It was built from 6 plies of cardboard with each layer running perpendicular to the corrugations in the previous layer. This imparts a lot of stiffness to the structure. So essentially this is a boat inside a boat inside a boat get the idea. There are also four airtight floatation bulkheads (two in each end) in the construction which means I'd have to breach four compartments plus the main passenger section before the cardboard boat would totally sink. In addition to this all end corrugations are sealed with glue and this prevents wicking of water up through the edge corrugations and stiffens all edges and makes them crush-proof.

All the cardboard edges and joints were also seamed by gluing on sheetrock tape. So there are no voids in any of the joints or connection points. The cardboard used is from salvaged industrial packing materials and has a burst strength of 300 PSI. So, its doubtful serious damage will occur if we are careful. I'm not saying this thing couldn't sink, just that it would have to sustain considerable damage which would in effect mean our entire sculpture in all likelihood would also be disabled as well. My plan to add a plastic cover over the boat would make it even more bulletproof. The Sono-tube outriggers are waxed so they too have water repellent qualities. The pontoons also have a sealed bulkhead for every foot of length so these floats would also require multiple punctures to sustain severe damage. I used Sono-tubes exclusively for the 2005 Fools Rules Regatta and built a homemade cardboard sailing catamaran which won first place in the unlimited class with a crew of 5 onboard. I'm confident I have bulletproof floatation.

For a look at the cardboard pirogue & sailing catamaran I have attached a few pictures.


Re: Virgin Kinetic Sculpture Racer

Posted: 12 Feb 2011, 7:08 pm
by Elliot
Sounds -- and looks -- like you have this project well in hand, Dave.

Outrigger pontoons will stabilize you nicely, yes. I built these...


...from plastic drain pipe filled with foam. (They are supposed to look like exhaust pipes on the "motorcycle".

There is a shortcut for calculating buoyancy: 1 cubic foot = 60 pounds.

Carry on!

Re: Virgin Kinetic Sculpture Racer

Posted: 27 Feb 2011, 8:18 pm
by Candy Haus Frau
Candy Haus design:

Thanks for all the positive words about the design of the Candy Haus! You have pretty much nailed all the design problems, too. We had a lot of trouble with the front wheels: one of our front wheels taco-ed within feet of the starting line (we had brought extra wheels and simply replaced it, rather than try to repair); the front wheel frame bent during the last few feet of the sand obstacle, but we were able to bend it back into place. The bent frame was then much weaker, which is why we opted to get off the front bikes and push it through the mud obstacle (the pilots in back stayed on and power pedaled). Amazingly enough we survived the entire race!

We had an ace welder helping us with the construction (Les, the guy with the beard in the front). He did a great job of getting the various metals of the bikes and frames to hold together. The entire structure still resides, in all its mediocre glory, in our garage.

This year we will be going with a different design to keep things fresh and because we like to fail in new and spectacular ways each year--never the same disaster twice is our motto!

Re: Virgin Kinetic Sculpture Racer

Posted: 28 Mar 2011, 1:58 pm
by Eggroll
Based on the description of your craft, my first question is how much will it weigh? I've seen a lot of bike bolt on vehicles (like the Candy Haus) over the last 22 years, but they don't lend themselves to very heavy crafts. As for the drive system, I assume you will want a single prop, so you're likely going to run a jack shaft to feed it. You could arrange 2 separate systems to delver power to your wheels and your water drive, but why bother? The tech involved in transferring power from multiple chain drives to a jack shaft, then from a jack shaft to a differential is not all that complicated.

OK, it may be a bit complicated to the uninitiated, and you may not have enough time to get up to speed for this year, but it's really not that bad. Here is a shot of Ken Beidelman's drive from one of his best machines (and that's saying a lot.) Assuming the photo I attached pops up, A is the point where the drive chain leave a std. bike drive. To allow for a wider range (a must here on the West Coast) Ken has placed another freewheel set on the jack shaft by welding on threaded adapters (B), but you could use single freewheel sets (BMX) or even fixed gears. The advantage of the freewheel is that, should you be coasting down hill at any speed the chain is less likely to come off due to lack of tension. If you choose to go this way, make certain that your threads both face the same direction. I'd hate to see your freewheel unscrew at the starting line! At points C (on the jack shaft) and D (the differential) there are two heavier gears at each point (one for sand and another for road) to allow for the use of motorcycle chain. I've seen Ken and other use a variation of this design for over a decade and it's always worked well.

The differential is the key. I've seen some folks try and use an adult tricycle unit, but they blow up. The unit we all use comes from Northern Hydraulics and runs about $100 and it's easy enough to make an adaptor plate to mount the final gears to the differential housing bolts. . The axel is about 3 ft long, but for his two man side by side seating Ken likes a longer axel, so he mills his own to fit the differential. I run a single or double in line, so the std. works out fine for me. Speaking of what works for me, I love to see big wheels and it's true that they can make some aspects of racing easier, but I have only run on really good 26" bike wheels and ATVs. I have 5 ACEs under my belt here in the mother race and 1 LEO from my one time in Corvallis, so I wouldn't be so fast to discount their use.

Re: Virgin Kinetic Sculpture Racer

Posted: 05 May 2011, 3:09 pm
by crazydave757
Despite my best efforts to build a kinetic sculpture I will not finish in time for this year’s race. I was hoping I would complete my creation last minute and then drive down to Baltimore and show up at the race minutes before it started, but this will not come to pass. This winter left everything buried underneath three feet of snow and the whole project ground to a standstill. The snow greatly inhibited my efforts as all my bike parts and materials were entombed in snow and ice and were inaccessible. I also underestimated the amount of time and work required to accomplish this epic task. I would like to wish all the participants who are ready to roll the best of luck for this year’s event.

Re: Virgin Kinetic Sculpture Racer

Posted: 05 May 2011, 4:17 pm
by DirBenev
Too bad! But very understandable. It sounds like you now have excellent plans for next year. I hope you can still attend as a glorious spectator!


Re: Virgin Kinetic Sculpture Racer

Posted: 05 May 2011, 6:21 pm
by Elliot
Crazydave, have you read my "Mayor Murdered..." story on this board? It tells of my first time at a race. We went something like 50 feet, and still won People's Choice! So if you have something at all, you might want to show up as a static display, if nothing else.

Re: Virgin Kinetic Sculpture Racer

Posted: 02 Jun 2011, 6:20 pm
by nymedic881
OK OK I Give up,I'm now totally hooked,I"m a retired NYC firefighter/Paramedic who moved to Humbolt County California 5 years ago,I had NEVER hear of kenitics or the KSR but after seeing 4 of them it's a done deal,myself and my new wife of 3 years are GOING TO build one and try not to end our life in Humbolt,I am reading drawing and just abouty going out of my mind consuming everything I can about this and have tons of Questions,even with me being in the middle of the place where KSR was born( KSR Grand Championship Race held here)my best information to date comes from the Baltamore race I'm truly hopping to connect with more racers to gain some info..want to have this thing in it's 1st race within the next 2 years so please help a totally hooked man get this done before they close the thanks !!!!

Re: Virgin Kinetic Sculpture Racer

Posted: 02 Jun 2011, 11:10 pm
by Elliot
Welcome to the fold, NY Medic! Don't think for a moment that you are too old for KSR. There are participants in their 70s, and occasionally 80s. I take it you were a Glorious Spectator at last weekend's Grand Championship, so you might want to get your project started while the iron is hot.