I’ve been tinkering with my Milan hood, making some minor improvements so I thought I’d do a quick update.
Closable flush NACA duct flap
I really like having a closable NACA duct on my DF – enough so that I’ve added one to my Milan SL.
The flap is adjusted using a lever mechanism similar to the one I used on my DF NACA duct.
Side Window moldings
I 3D printed these moldings in flexible TPU filament to hold the side windows in place. Formerly the side windows were just hot glued to the interior surface of the hood. It looked pretty messy.
Added Snoek-inspired Mirrors
I originally came up with these for the DF. They actually fit the Milan hood better on the flat sides of the knee humps. These mirrors replace the smaller Spin mirrors that were located closer to the visor where the plastic white plugs now fill the holes.
I’ve used various tools over the years to adjust toe in on my race cars, trikes and velomobiles. Mostly, I’ve used various forms of trammels like this nice one built for me by my friend Bill (A2naut on Bentrider).
or this gizmo that I put together using 80-20 T-slot profiles.
There are a couple of problems using these on velomobiles. You have to slide them under the velomobile which has minimal ground clearance. With the trammel, you’ve got to keep sliding the tool in and out to measure in front of and behind the wheesl. The other problem is that some velomobiles have enclosed front wheels so very little of the wheel is exposed below the bodywork.
So I looked at various commercially available toe-in gauges to get some ideas. Most are meant for use with race cars and involve lasers or measuring against an elevated string rectangle. Then I came across a simple type of product called Toe Plates. These are just 2 plates that are bolted onto the front wheels of the car. They use simple tape measures across the plates in front of and behind the wheels to determine the actual toe setting. These wouldn’t work with the velomobiles for a lot of reasons, but I liked the idea.
Looking around the garage, I found some 8020 T-slot profiles and some 8020 90 deg threaded nubs. Using these pieces, I concocted this low slung toe gauge. It’s similar to one that I had seen on The Velomobile Observer blog a long time ago. Each bar is placed along a front wheel. The 2 nubs on each bar hold M8 bolts which are screwed into the nub at the same length to form pointers to be pressed against the rim. Using these pointers eliminates any interference from the tires. The ends of the bars are pulled together by the bungee straps that run under the velomobile. These are adjusted with just enough tension to keep the pointers pressed against the rims. The tape measures are used to measure the distance across the bars at the same distance in front of and behind the wheels. So for example, if the wheels are pointed straight ahead, the bars would be parallel and the measurements would be identical and so on. The 4 red plastic pieces are just supports to keep the bars flat on the ground. I’ll probably replace those with some 8020 aluminum pieces that would be more robust.
Here you see the tool used on the Milan SL with its enclosed front wheels.
I used the tool today to check the toe-in on the DF and the Milan. I was pretty happy with the ease of use and the repeatability of the measurements. The 80-20 products are very precisely machined so once I had all of the pieces bolted together, I had a tool with no slop and very straight edges.
I’ve decided not to update the steering plates on the DF to the newer geometry plates. These plates really improve the straight line stability in cross winds. However, they increase the turning radius noticeably.
Recently, I was riding in some gusty winds and was reminded how easily the DF can be pushed around. Even though I’m not crazy about the aesthetics, I decided to add a tail extension. I had added one to my DFXL in the past so I knew how well it works. Here is the DF with its new tail extension:
I’ve since added a column of red LEDs along the trailing edge behind a cast resin lens and some single yellow LED turn indicators.
This is not exciting news but it may be of interest to a few people. I was looking at a photo of a DF seat mount built by Garrie Hill, when I thought that I saw a bag fitted to the back side of the DF seat. It turned out that it was not a bag. But I liked the idea of using that space for a lightweight bag.
This is the bag that I came up with. The material is a nylon mesh fabric that I bought on eBay. I don’t have a proper sewing machine so it’s put together with contact cement and held in place with velcro. It’s about 9 inches wide at the top, 12 inches wide at the bottom and 14″ from top to bottom.
When I sold my red DFXL, I included my shade cap in the sale. It was a copy that I made of the factory part sold by ICB. It worked OK, but I never really liked the way it mounted with the 2 straight struts holding up the front (shown below).
With spring around the corner, I need to replace that shade cap. But I want something that looks a little better than my previous shade cap. So I came up with a hood, popped out of my aero hood mold, that has a little more structure. It maintains the sections that interface with the cockpit so no straight struts are needed. I opened up the visor area and side windows quite a bit to promote airflow. The sides and visor area openings are contiguous so the cap area looks like it’s floating without any structure holding it up. It did require some interior bracing to stabilize the cap area. (By the way… I’m not sure I like the white cap paint job…)
I haven’t tried the cap out in warm weather yet. I think that there’s enough open area to allow air in, but may need some exit vents to allow that air to flow through the cockpit.
Update: After a short test, I noticed that as the speed increases, less air enters the cockpit through the front NACA duct. This may be due to chaotic air flow inside the cockpit. With that in mind, I’ve added a new air exit duct to see if that can improve the air flow out of the cockpit.
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.
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.
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.
I used hollow Sturmey Archer brake cable adjusting screws to mount the mirrors. This allowed me to pass the wiring to the LEDs through the screw without having to drill any more holes in the body.
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.
Plexus Cleaner – (Optional) This is a great cleaner for plastics but pretty pricey.
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.