[From Alan Ball, February 2, 2010]
High Rider dimensions
Low Rider Dimensions
Before we go into detailed design for the actual Morph 4 prototype, I asked Alan to check the key dimensions of Morph 4 against those for Morph 2. Everything looks good in the drawing above.Trail in Low Rider: 2.5" (okay, a bit more trail than Morph 2's 1.3")
These are the measurements for Morph 2. Note that Morph 2 doesn't have the automatic seat adjustment system, and that it doesn't come down as far.All of these dimensions and angles look good. Nice drawings, Alan. Very clear and simple.
[From Alan Ball: January 12, 2010]
A while ago you requested some orthographic views with key dimensions called out for the M4. Check out the drawing I have attached here. Is this what you had in mind?
For comparison , I have included a drawing of the M2 geometry, which I documented in CAD and was measured and confirmed against M2. As you can see, the basic dimensions are almost the same, with differences occurring due to M4 greater range of morphing motion.
We started the session by looking at the issue of curved vs. straight tubes. Alan turned on the layer that shows where the main joints are.
Just in case you want some dimensions and angles.
Curvy Morph in upright mode. Bill expresses concerns about curved tubes. One concern is how it looks...not as angular as our earlier designs, and also the difficulty in fabrication. Discussion moves to what would a design with straight tubes look like. Alan made some screen captures and we did some overlay drawings.
Here we straighten some of the tubes.
Now the upper tube has once joint, rather than two.
Lower member also now has one joint.
Now we look at straightening the main tube. But it bangs into the seat, which can change angles.
Now the main straight tube is below the seat joints.
Adding the gusset tube to the head tube.
Another design for the main tube. One little weld, and then it hits the head tube in the middle.
How it looks in low rider mode.
Now exploring how to make the members look good in low rider. Want them to be parallel.
The upper, blue member now has an angle that causes the tube to be parallel to the green one on the bottom.
Same design in high rider mode.
We discussed that there are 6 places where we have a fork. (oh my!). Need to figure out something that is lightweight, low cost, and looks good, and then gets repeated six times.
The center upper drawing shows a very short fork at #6.We agreed that Alan should take another pass at the frame design, and we'll get back on the phone to refine further. Note that the initial curvy frame that he designed was about 3 hours of work! We are getting very fast at being able to make new morph designs in very minimal time.
John Baron sent along these images of the morphing handcycle test rig progress. The goal of the test rig is to figure out how to get the best "float" so the bike goes down and comes up effortlessly.
Below is the gas spring we're using: http://www.mcmaster.com/#9416k51/=31aoi8
This Powerpoint presentation reviews today's online design session with Alan Ball, Rory McCarthy, and Bill Warner. The goal is to nail down the geometry of the morphing mechanism in stick figure, and then proceed with some basic frame design.
Now that we've got two morphing vehicles on the road, the benefits of the Morph II design are easy to see. It has excellent steering geometry in low rider and high rider modes. Mainly, we need to fix the issue that we can't adjust the seat angle, and the struts provided on Morph II turned out to be an unworkable solution due to the high forces that travel through those struts while you are sitting, and even higher forces while you are riding.
This presentation compares Morph II, the Bobby Hall, and a proposed new design, which essentially keeps the Morph II morphing frame, but allows it to morph through its full travel. Next will the the challenge of designing a seat that allows the proper adjustments.