The previous posts review the Travel Bike, because it shares many design elements with the Morph. Having just spent the weekend in Newport on the Travel Bike (as I wait for the Morph 4 to be completed!), I wondered if we could use the very cool hinged footrests from the Travel Bike. The short answer: No. The Travel Bike, as compact as it is, is way longer than the Morph in high rider mode. And your legs sit well ahead of the steerer tube, as opposed to behind the steerer tube in the Travel Bike. Too bad. The Travel Bike's footrests are light and functional. Here's some more details.
Side view of the Travel Bike.
I used Keynote's instant alpha feature to grab the CAD Man from the Morph pictures. I scaled both drawing so the front wheel was the same size.
Using the same scaling techniques to see the Morph in Low Rider next to the travel bike. Note that you sit about one full head height lower. The overall length is about the same.
Adding the Morph in high rider, we see how much shorter and higher the bike is, even compared with the (mostly grayed out) Travel bike.
It's interesting to note how much more your leg bends from low rider to high rider. This is because the seat moves up and forward, but the footrest stays in a similar place (it does rotate about the front contact point, I think.)
Like I said, no but you'll see.
The instant alpha took away some of the foot of our CAD Man.
These footrests are hinged at the top of the vertical orange line, and also where the two lines meet. Go off a big curb? The footrest just bends forward, no problem.
Red lines show center line of your shin in both bikes.
I hadn't realized that the seating position relative to the steering axis was that much different. It's a good 16" (size of the front wheel). This keeps the Morph short, which is really crucial for indoor maneuverability.
And there you have it.
Since the Morph will use some of the design concepts of my Travel Bike, here is a photo survey showing how the bike comes apart. It gets very small, and will fit in most trunks, and can go on small airplanes as well. The Morph will use the same coupler on the main frame, and it will have a similar fold-down seat. The Morph will put the centering spring entirely on the front, so the step of unhooking the centering spring will not be required.
Click on the small right arrow to view successive images below. This will give you a photo animation of how the Travel Bike comes apart:
Click on the small right arrow to view successive images above. This will give you a photo animation of how the Travel Bike comes apart.Below is a photo survey showing more detail about the Travel Bike. It has a coaster brake in the hub, so the cam-based reversing brake isn't needed. The internal-gear hub has 8 speeds, which is okay for basic needs. The Morph has a full derailleur system, which will give it much more gear range.
Travel Bike photo survey.
Here's a picture of me on the Travel Bike. These photos were taken on a trip to Atlantis in the Bahamas. Thanks to Miles D. for demonstrating the disassembly of the handcycle.
This post will go over the centering spring design we'll be using on the Morph. This design has been used on the New England Handcycle for over 30 years with great success, and it was carried over to the Travel Bike (shown below) that was built for me by One-Off Titanium (Mike Augspurger). The Travel bike and the Morph share many design elements, including the 16" front wheel, the coupler to allow breaking the main frame into
Here is the centering spring as installed on my Travel Bike. Note the silver coupler in the main tube. Because the bike comes apart here, there two carabeners below allow the centering spring to be dismantled when the bike is taken apart.
Closeup of the centering spring. I can't say it's pretty, but it works perfectly, as the explanations below will outline. This same mechanism will be incorporated on the Morph, but on the front end, rather than under the main tube. And, we'll make it look much nicer.
This series of three photos shows how one chain becomes slack and the other stays tight when the rider starts turning the wheel.
This is a bottom view (well, the bike is flipped vertically) showing the size of the wings.
When the wheel is turned, the wings pull on one chain, thereby stretching the elastic.
As the wheel is turned, the moment starts decreasing, while the stretch on the elastic, (I call it the "gap"), increases. The lines in red on the left side show the relative sizes of the moment and the gap.
As you start to turn more sharply, moment starts to fall quickly, even though the elastic is still being stretched more. This creates exactly the characteristic you want: Good centering near center, and up to about 45 degrees, and then a reduction in centering as you turn even more. Because the handcycle can make extremely tight turns, even more than 90 degrees, its important the the centering spring not fight you when you're doing these tight maneuvers.
At 100 degrees, we see that that gap is big, but the moment has dropped to almost zero. Just perfect. You can steer as extremely as you want, but lets say you need to grab the rear wheels and push like a wheelchair -- the centering spring will make sure the wheel stays straight.
Below are the five slides in a picture viewer, so you can click through them without the explanations above.
Here is the Powerpoint in case you'd like to play with it.
The Morph will implement the same mechanism, but the wings will be fixed to the main tube, and the elastic will be on the front end.
One of the design issues we've been working is how to get the seat back in high rider mode to tilt back enough.