I’ve seen old photos on the internet of some custom modifications on Daniel Fenn’s DF. These mods were never made available for sale. One that looked interesting was the tail extension shown below.
A friend of mine, Doug from Riverside, recently was able to talk Daniel into selling him a couple of copies. Doug then surprised me by sending me one. I know that the extension probably wouldn’t make any speed difference for me at the speeds that I travel, but I wondered if it might improve stability in cross winds.
I’ve been working with Peter Borenstadt on a few aero pieces for his upcoming Battle Mountain run in his DF (see the “aero” hood in an earlier post). Peter had a home made tail extension so I asked him if he’d like to borrow the real thing. Of course he said yes. Before shipping it off to him, I decided to make a quick mold and copy just in case anything happened to the original. Making the mold wasn’t difficult. But it was tricky laying up the part because of its very thin trailing edge.
Here’s the original extension with temporary flanges and the resulting 2-piece mold.
To lay up the trailing edge of the part, I chopped up some carbon fiber material into short strands. I shaped a piece of wood with a skinny rounded tip that fit into the radius of the trailing edge. After applying the gel coat and letting it partially cure, I put the chopped carbon fiber along the trailing edge and up the walls a bit then tapped it into position with the stick. Then I just wet laid up 2 layers of cloth in the rest of the mold and overlapped the chop. The part turned out pretty nice with no voids but a bit heavier than the original. The original was just a single layer with no gel coat.
Here’s my copy of the tail extension, painted to match
I tried it out for the first time yesterday on a nice ride with my friend Gregory (who rode my WAW). I couldn’t feel any changes in stability nor speed. At least my red electrical tape mounting system worked as the tail didn’t fly off during the ride.
A while back, I decided to make a mold of the factory DF race hood. This would give me the ability to make copies that could be modified for various experiments. In building that mold, I misjudged the draft of the hood. I mistakenly thought that I could extract my factory part from a 2 piece mold, split longitudinally. It turned out that the shapes around the visor locked my hood into the mold. I spent the weekend trying to extract my hood from the mold. I was almost ready to toss in the towel and start cutting the mold apart to rescue the hood. But with a bit more persistence I managed pull the hood from the mold without cutting anything. After almost losing my factory hood to the mold, I realized that this mold was not usable.
I set the mold aside and forgot about it for a few months. Then I began discussing with Peter Borenstadt (a regular competitor at Battle Mountain) how one could make a more aerodynamic hood for the DF. That got me thinking that I could modify my failed mold enough to yield a part that would be a good starting point for a buck for an “aero” hood.
So I cut the offending sections out of the mold and filled in the openings to build a plain looking hood (without the indentations for the visor). I then formed a piece of plastic (and later aluminum sheet) to change the angle of the visor area to be more laid back.
After a few rounds of bondo, sanding and primer, I ended up with this very blank buck. I was able to build a 2 piece mold from this buck, split longitudinally, since the shape was so simple. With the mold completed, I could go crazy and make all kinds of variations of the aero hood.
The first order of business was to make a test hood for Peter to play with. I thought that it would be nice to have a flush mounted visor. Here you can see how I came up with the inset surface to mount the visor.
To hold the hood in place, I copied the factory bungee tie down idea. I 3D printed a squish mold to form the carbon fiber strips to hold the bungees. I 3D printed the hooks that clip on to the cockpit rim.
Peter and I discussed the most efficient ways to extract air from the cockpit, considering that I had closed off all openings of the hood. Initially, I thought that some extractor ducts on the sides or top would be a good idea. Here are some photoshopped ideas.
Peter took a look at my ideas and explained that in his testing, the best extraction (with the least drag) occurred with a small opening (only a few inches wide) on the top as far back as possible.
Here’s what we came up with for the vent.
Here’s the first hood prior to being shipped to Peter. Since this is basically a throw away piece, I didn’t bother to match Peter’s DF’s yellow color. He may end up adding some cuts and holes that we will incorporate into future hoods.
Here’s the hood mounted on Peter’s DF. Peter did an excellent job of refining the fit.
Peter’s tests so far show the hood to offer only a modest improvement in speed. Here are Peter’s comments:
I did three runs with each top in fairly quick succession. The temperature and wind were very similar. The road is about a two mile shallow downhill going along the bottom of a canyon, with large trees on both sides. The canopy covers the top along most of the test section. All the runs were consistent and the racing top was consistently faster. The vent works excellently. Starting at about 16-17 mph there was a nice stream of fresh air coming up from boom vent into the head area. Flowing by my face and around my head. I sat at the start for a few minutes to see if it fogs up easily and it did only slightly around the bottom visor edge. Fog instantly disappeared as soon as I started moving. It was cool and humid, so it was a good test. Interestingly, the ride seemed more stable at speeds over 40. It was just a small difference. Overall, I’m pretty happy with the results. When it is taped on, it should be even faster. I think I’ll be able to tape the visor as well, since the vent is working so well. I may reduce the front intake to a bare minimum, or close it off and make a small hole in the bottom center of the visor. So here re the speeds: STD roof, closed visor: 44.5, 44.2, 44.6 Racing roof: 45.1, 44.8, 45.2 Average for stock roof: 44.43 For racing roof: 45.03 Difference +0.6 mph for racing roof. About +1.35% speed increase. At higher speeds it should be more effective. At 55 mph it should be closer to 1 mph more. The noise level was very similar to the stock roof.
Moving on to some other experimental pieces… I saw photos online of a product that ICB was prototyping as a partial hood to provide shade. It was similar in concept to the Flevo Roof that many riders add to their velomobiles – only a bit more stylish. Anything to reduce my exposure to the sun sounded worthwhile. So looking at the photos, I copied ICB’s idea and built a “Sun Cap”. Here’s what I came up with.
While this did a decent job of providing some sun protection, I thought that it could have been more aerodynamic and could have provided more sun protection.
This lead to my next experiment. I thought that I could make a hood that had plenty of openings for air flow yet provide more shade and perhaps be a bit more aerodynamic than the Sun Cap. It wouldn’t be as enclosed as the factory hood. It would have more openings so that it could provide enough air for use on warmer days. So here’s my “Shade Hood”. I’ve ridden it on days where the temperature was in the mid 70s. It seems to move enough air to keep me comfortable. It definitely provides more shade than the the small Sun Cap. Notice that it doesn’t accommodate the factory flip up visor so I came up with a simple, magnet-mounted visor that I can pop on and off from within the cockpit while riding.
I’ve since popped out another blank hood. In the photo below you can see that I’ve outlined the cutouts of the Shade Hood for reference. I’m currently thinking of cutting it up to make something like one of these open top cockpit covers (without the NACA duct).
Update: I made cockpit cover similar to the white ones above, but I wasn’t happy with the clear visor. So I finished the sharp edges with a thin rubber strip. If you look closely, you can see that I had to add 2 more tie downs towards the back to get it to lie correctly against the body. (not ideal). To be honest, I’m not sure when I would choose to use this cockpit cover, but it was fun to make.
I think that I will make one last hood. I would like to have an aero hood similar to the one that I made for Peter with a flush mounted visor, no side openings and a small vent on the top. However, I think that I’ll go with a wider visor so that I can see my mirrors similar in shape to the Shade Hood’s visor above.
Unfortunately, I’ve had to withdraw from my purchase of the new velomobile. (Thanks Doug for being so understanding). This means that I won’t be able to sell the WAW at this time. I apologize to those potential buyers who expressed interest.
Carbon Fiber main section
Carbon/Kevlar nose and tail sections
Visible carbon wheel covers
N4 Nose with SPAI (Stagnation Point Air Intake) and 2 headlights
T3 tail with integrated rear lights
Stowable Katanga race hood
Daylight LEDs and turn signals in mirror caps
Integrated USB accessory plug
Triple 155mm crankset ( 60-39-30 ) – Pedals not included
Alligt bottom bracket holder and post (stock bottom bracket holder also included)
Alligt 60T chainring with integrated chain guard (prevents overshifting)
11-36 10 speed cassette
SRAM X0 10 speed rear derailleur
SRAM TT500 10 speed Bar End shifters
Rear suspension upgrade with chain protector
Includes all of the hardware to revert back to rigid rear end with chain protector
Upgraded Ginkgo front wheels with black, machined 90mm drums
Near new Schwalbe Pro One tires front and rear
Single layer Ventisit seat pad
Reusable Katanga factory wooden crate
Any other components not specified are as supplied by Katanga
Can provide custom vinyl graphics (we’ll have to talk about this)
Custom add-ons (see below)
These parts came out of my workshop – not from Katanga.
The sun cap on the DFXL worked out pretty well. So I thought I’d build one for the WAW. I like the shape of the DF’s so I started with that. It was easier to mount on the WAW than on the DF since the WAW provides very nice clamps on the inside sides of the manhole cover. Here are some photos:
I’ll need to do some testing to make sure that it provides the shade and cooling without hurting the performance too much.
IntercityBike has been experimenting with a sun cap for the DF meant to shield the rider from the sun – not necessarily improve the aerodynamics. Several people have prototypes and have been reporting on them on BentriderOnline. Some people are claiming that the sun cap actually improves the aerodynamics. Here’s an example.
This sounded like a good idea to me. I had thought about making a mold of my race hood for a long time. I’d like to be able to experiment with different hood configurations. With the idea of the sun cap floating around, I decided to start the mold of my factory race hood.
I won’t go into it here, but let it be known that I deserved an F- on that mold. The hood has some tricky shapes and I misjudged the parting lines for making it a 2-piece mold. It took me many hours of hard work to extract my original race hood from my mold. Clearly, I would never be able to use this mold to make a full race hood. But after looking at it a while, I realized that I could at least make a sun cap using this mold. So I made one sun cap, body worked it and painted it. From that piece I made a dedicated, 1 piece sun cap mold.
Once I was able to make the part, I had to come up with a good mounting system. I got fancy designing all kinds of aerodynamic struts. None of my ideas panned out, so I resorted to copying a mounting solution posted by RobertM on BentriderOnline. This solution consisted of 2 round pieces of aluminum tubing with 3D printed plastic attachments. I used his idea of attaching 2 bungees at the rear of the hood to hold it all in place. Here’s my first example. I’ll be testing this soon to make sure that it doesn’t fly off or rattle too much.
I was able to position the struts so that my windscreen was still usable with the sun cap.
Thanks to RobertM for posting such good descriptions and photos on BentriderOnline of his sun cap.
I logged into BROL tonight and checked the classified adds as I usually do. I was surprised to see a 2013 Catrike 700 for sale at an incredibly low price. I couldn’t pass it up. This will be my 5th Catrike 700.
It comes with an extra set of high end wheels and some other very expensive components. I’ll probably use it as a daily driver trike and save the wear and tear on my Monster. I’ll see if my wife happens to like it. If so, I’ll take back the Trice Special and make it my daily driver and give her the 700. I doubt that this will happen. I have a hunch that the 700 will be too laid back for her.
Here’s a photo of the 700 at my house after cleaning it up a bit. I also replaced the later seat cover with a first generation seat cover that I have left from one of my previous 700s. The newer seat covers are about a pound heavier and have a seam (side to side) across the middle. I find the seam to be a bit uncomfortable.
For once I was able to hand off a sold trike directly to the buyer without having to pack and ship it. The buyer came up to Santa Barbara from Riverside to pick up the Micro today. We set the boom length, seat angle, chain length and derailleur settings. We took a short ride to Goleta Beach then remedied a squealing brake before loading it in the truck.