There's a dude on BRO who owns a vendetta and a velo. He'd be a good person to ask. He lives in the Seattle area.
Personally, I'm not convinced it would help on anything but a flat course. If you look at the recumbent records, velomobiles don't appear to be faster *overall.* Just on the flats and downhill.
The vendetta, nocom and M5 chr dominate.
As Dr. Plager states above, most velomobiles are mucho heavier than an F40 which results in a lot more uphill effort.
I own and ride a velomobile and a Vendetta.
My orange Strada velomobile with water bottles and gear is probably around 75+ pounds plus my 200+ pound carcass.
My Vendetta is around 22+ pounds plus the above mentioned carcass weight.
So I'm hauling around 53+ pounds MORE when riding my velo. The nosecone and sock for an F40 is probably just a few pounds which means it gains a similar aero advantage to my velo without the weight penalty.
Here are some comparisons:
Take a look at Harry Lieben's times in his velo where everything is mostly flat. For June 17, 2017 for his 27.2 mile ride he averaged 23.1 mph but that was with about 170 ft of climbing.
https://ridewithgps.com/trips/15361684
Here is my Strada velomobiles 28.2 mile ride on June 10, 2017 where I averaged 16.2 mph with 1370 feet of climbing. I think I was riding with my Flevobike roof which is a bit of an aerodynamic parachute. My racecap gives me a few more mph in speed. Also Harry rides all the time and is a much stronger velo rider than I am.
https://ridewithgps.com/trips/15195012
Here is a 22+ mile ride on my Vendetta on August 6, 2016 with a 17.5 mph average and around 1070 feet of climbing.
https://ridewithgps.com/trips/10362249
Here is a 20.1 mile ride on my Vendetta on June 18, 2016 for a one hour time trial on a car race track where I averaged 18.7 mph during the annual Michigan Human Powered Vehicle (HPV) rally with about 520 feet of climbing. I'll be there again this year on June 24-25, 2017 with my Vendetta. I raced both my velo and the V
https://ridewithgps.com/trips/9519834
In 2015 I rode my velomobile in Roll Over Cape Cod (ROCC) with about 12-15 velomobiles - we picked up a few and dropped a few during the course of the weekend. There was a lot of stop and go and bunching and yo-yo-ing during the ride as most of us had never ridden together before and for almost all of us it was the first time riding the route we took.
Outbound: Woods Hole to Truro (southern route) - about 83 miles and 15 mph avg:
https://ridewithgps.com/trips/6021124
Return: Truro to Woods Hole (northern route) - about 92 miles and 14 mph avg:
https://ridewithgps.com/trips/6021124
Edit: Of course riding in cold and foul weather is surprisingly comfortable in my velo. I'm not sure if an F40 comes close but Doug Grosjean can tell you he has owned both.
https://www.facebook.com/douggrosjean
-Eric