Velomobile FAQ

Recently a photo of me riding my DF velomobile was posted on a local news web site called Ed Hat. There were a few comments and questions about the velomobile. I posted a pretty long response that tried to explain what a velomobile is all about.

After spending a fair bit of time composing this response, I thought that I might as well capture it for this site as an FAQ. You can see my Velomobile FAQ here.

I also get a lot of questions about my velomobiles while stopped at an intersection or while taking a rest stop. I wanted a quick way to point the curious person to more information. So I’ve added a QR code sticker to the side of my velomobiles. I generated the QR code that points to my FAQ on a free site at http://qrcode-monkey.com and then laser printed that code on sticker paper. Anyone who’s curious and knows what a QR code is can use their smart phone to snap a photo of the side of my velomobile and let the QR code navigate them to my Velomobile FAQ page.

If you are interested in pointing to a velomobile FAQ, I’d suggest pointing to The Velomobile Knowledge Base. This is a much more comprehensive source of information than my bare-bones page.

A word of caution… Some people are rightly reluctant to use a QR code to navigate to a website. There are stories out there of phishing scams that involve QR codes. I’ve looked into http://qrcode-monkey.com (which I used to generate my QR code) and it seems to be a popular and safe QR code generator. Do your own research.

Home Grown DF Hood Gets an Exit Vent

With the addition of the NACA duct and fans, I seem to be getting enough air flowing through the cockpit that I can leave my Lexan visor installed during a ride without overheating. Up until recently, I still left my side windows open so there was an easy path for air to exit the cockpit. Then I decided to install some Lexan lenses over the side windows to improve the aerodynamics (at least in my head). This seemed to choke off the flow of air coming from the fans and the NACA duct.

Then I remembered the small exit vent that I constructed for the aero hood that I made for Peter B’s DF. That hood had no side windows so it needed to provide a way for air to exit the cockpit. Here is that vent under construction…

Fortunately, I made a small mold from that vent so that I could reproduce it easily. So I thought it was worth a shot to try installing a copy of that vent on my own homegrown hood. Here, you can see the progression of grafting the vent into the hood.

It seems to noticeably increase the air flow through the cockpit. However, without proper testing, I don’t know if it has any negative effect on the aerodynamics. My list of features to test continues to grow.

Lighted Mirror Covers

One of the features of my Milan GT that I really liked was the LED lights in the mirror covers. These acted individually as turn indicators and together as emergency flashers. I’ve been meaning to get around to adding LEDs to my Snoek-inspired mirror covers. There were a couple of small electrical issues to overcome but I think I’ve got them figured out.

Without going into a lot of detail, I came up with these 12V LEDs from Amazon that worked out well. I had to add a little structure to the interior of the cover to mount them. I 3D printed these covers using clear PETG, then painted the blue on all but the point. I also had to deal with the fact that the DF electrical system is based on a 7V battery. These LEDs require 12V. So I had to do some funny business to bring in 12V for these LEDs and the ones in the hood side markers.

Here are some photos of a mirror cover

I use the same LEDs in the hood side markers.

Antifog Insert for the DF Hood Visor

This is not my original idea. I came across this somewhere on the German Velomobile forum. It sounded easy enough to do so I thought I’d give it a go. The idea is to add another layer of Lexan to the interior side of the visor, leaving an air gap between it and the visor. This layer (or insert) becomes the interior surface. The air gap prevents the cold temperatures from transferring to the insert so condensation (fog) is less likely to form. This is the same idea as employed by the Pinlock system used on motorcycle helmet visors.

Here’s what I came up with…

Materials needed:

Steps

  • Design a pattern for the antifog insert that’s smaller than the visor opening in the hood.
  • Trace the pattern on to the Lexan sheet’s protective film.
  • Using some large scissors, cut out the pattern.
  • Remove the protective film from one side of the insert. This will be the side facing the factory visor.
  • Apply the double sided tape to this exposed side of the insert near the edge. Leave the red backing film on the double sided tape. Use a razor to remove any excess tape that goes beyond the edge of the insert. Be careful not to introduce any smudges or fingerprints to the tape or to the exposed side of the insert.

Antifog insert with double sided tape with red protective film still in place.

  • Remove the visor from the hood and clean it with something like Plexus.
  • Remove the red backing film from the tape. Position the insert carefully over the inside surface of the factory visor without letting the tape touch the visor yet.
  • Once you’re happy with the position of the insert, start at the centers of the upper and lower edges of the insert to press the taped edges to the visor, working towards the sides of the insert. You want the insert to follow the curve of the visor leaving an air gap between the insert and visor.

Insert installed with protective film removed.

  • Remove the remaining protective film from the non-taped side of the insert.
  • Reinstall the visor on the hood. That’s it.

The antifog insert has worked surprisingly well during a couple of early morning rides.

DF Dashboard

I’ve been playing with various configurations of NACA ducts, extension ducts and electric fans on the DF to add a bit of airflow through the cockpit. The more that I tinkered, the more complicated the cockpit got. So I decided to try to organize the cooling and sort of wrap it all up in a dashboard. The idea was to provide a single piece that surrounded the vent from the NACA duct, incorporated the fans and organized the fan and switching wiring. Here’s what I came up with…

Below you see the plug on the left, made from 1″ pink foam sheet, bondo and paint. The resulting mold is on the right. I should have made a 2-part mold. Extracting the plug and then the part from the mold was very difficult.

The resulting part is on the left. On the right is the backside of the part with the fans and switches installed

This shows how the ducting and dashboard pieces fit together.

The dashboard installed:

“Screwless” Derailleur Cover For the DF

This modification falls under the category of “that guy must have too much time on his hands”. I’ve admired how the Alpha 7 foregoes the use of screws to mount the front access panel and the rear derailleur panel. The DF has unsightly M4 screws holding both panels in place. I’ve already converted the mounting of my DF’s front access panel from screws to magnets. However, my rear derailleur panel was still held on with M4 screws. OK. This is really a pretty trivial thing. I know. But, with the encouragement of my friend, Doug, I decided to convert my panel to mount securely with magnets. This modification had to be reversible so no permanent changes would be made to the DF.

I first made a mold of my existing rear panel so that I could make my own copies and keep my factory panel intact. I laid up my first part with a layer of gelcoat and 2 plys of carbon fiber twill. This part came out slightly thicker than stock by still usable.

Next, I had to come up with a way to mount the magnets on the DF body in a non-permanent way. I ended up doing something similar to my approach with the front panel. I stretched some thin flexible abs plastic sheet (the orange pieces in the photo below) across the screw holes and taped some magnets on the backside of the plastic. I used some M4 button head screws and nuts in the stock holes to mount the strips. The magnets were held on with gorilla tape. The magnets on the panel were glued in place with E6000 glue.

The panel mounts with a loud “thunk” and seems very secure. I’ll wait until I’ve had a few successful rough rides before I declare victory but I’m pretty confident that the panel will stay in place.

Snoek-Inspired Mirrors for the DF

The Snoek is a new velomobile from Velomobile.nl. It is extremely small, light and supposedly fast. One of the details that caught my eye is its aerodynamic mirror cover. It is sort of a half cone that extends from a half round mirror. I believe that the mirror is the ubiquitous B&M Cyclestar mirror cut in half. This is the Snoek mirror…

I decided to come up with a similar mirror setup for my DF. It’s important to me to make few if any permanent changes to the DF. I always want the ability to revert back to stock. So whatever mirrors I came up with, they had to mount in the stock mirror holes.

I started with 2 B&M mirrors that I pilfered from one of my trikes. I cut them in half using a diamond cutoff wheel in my Dremel tool. I needed a way to mount the mirrors and the covers in just one hole per side. Below are models of the mirror mount (left) and the mirror covers.

To attach the mirror to the mirror mount, I cut off a piece of the stock B&M mirror’s ball/stem and cut M6 threads into its outside diameter. M5 screws are used to attach the mirror cover to the mount and to attach the mount to the body.

Here are the mirror covers that I came up with. I 3d printed them, sanded and painted them. I was concerned that they may be too far inboard to be effective. However, in my first test ride, I found that the visibility rearward was fine.

Closable NACA Duct for the DF

After noticing how much more air is passed by the Milan’s small NACA duct than the DF’s, I took a long look at the larger duct on the DF. One of the main differences was the depth of the ducts. The floor of DF’s duct seemed to rise so that there was a section of the duct that was very shallow. My guess is that this reduced area was causing some turbulence which reduced the air flow. I came up with this deeper duct. I also added an extension to the duct to feed the air closer to the rider. The air flow was improved greatly by these pieces.

I showed these changes to my friend Doug (the gentleman who sold me the Milan SL). He thought that it would be nice to make the duct closable with a flush flap of some sort. There are 3D printed NACA ducts sold in Germany for the Milan that have a closable flap. However, these NACA ducts won’t work directly on the DF due to the flat shape of the Milan’s top panel vs the curvy, recessed shape of the DF’s access panel.

I took Doug’s suggestion as a challenge and this is what I came up with. I first laid up a new NACA duct and extension duct as shown above. Then I laid up 2 new DF access panels – one to house the NACA duct shown above. The other panel was used as the donor for the flap. The flap needed to have the same curvature as the duct panel in order to perfectly fill the opening when closed. Extensions were added to the tip and trailing edge of the flap to allow it to lie flush with the top of the duct panel. The tip extension of the flap inserts into a loose slot in the front of the NACA duct to form a sort of hinge. All of the pieces in their rough, unpainted form are shown below.

To operate the flap, I needed a mechanism to push it up flush with the panel and down to touch the floor of the duct. The solution that I came up with was a simple stick screwed to a carbon fiber clevis (not shown) on the bottom of the flap and protruding through the floor of the duct. I 3D printed a piece to attach to the bottom of the duct to provide a rigid slot for the stick to ride in. The stick could easily be reached by the rider. I used a small piece of 5mm bungee attached to the stick to force it and the flap up and back. To lower the flap, the stick just needed to be pulled down. The friction caused by the bungee pulling the stick back against the 3D printed slot holds the flap in the down position. If needed, I can grind several notches in the stick to hold it more firmly in some in between positions. Below you can see the stick exiting the plastic slot attachment and the model of that slot attachment.

So how did it turn out? It works surprisingly well. I replaced the wooden stick with a nicer carbon fiber piece. I added a couple of very thin magnets to the bottom side of the panel and to the rear flange of the flap to locate the flap more precisely when being closed. Was it worth the trouble and complexity? Maybe. For the most part, I just ride with an open duct. So it would be a rare occasion that I’d want to be able to open and close the flap. That said… it was a fun exercise.

Here are some photos of the “finished” duct panel.

Milan Hood Version 3

The second version of my Milan hood was pretty successful. However, it still had a small problem that I should have addressed in an earlier version. Since I barely fit in the Milan SL, my knees can touch the inside surface of the knee bumps from time to time. Over a long ride, this can get a bit irritating. So I decided to make one more version of my hood with taller knee bumps.

Rather than build a new plug, I decided to modify the previous (V2) plug by adding more volume to its knee bumps. To do this, I laid up some knee bumps from the V2 mold and grafted them on to the V2 plug. Here is the progression of cutting and shaping the bumps.

Here you see the V3 plug, set up with flanges, before making the new mold. This time around I decided to incorporate the pesky leading edge lip into the main mold rather than as a separate mold and part as I had done on the previous 2 molds.

It’s difficult to notice the enhanced knee humps visually on the V3 hood. After all the work, I gained about 3/4″ of extra clearance for my knees.