May 31st, 2023 – Semley, England Adam and I research a new rotary superbike and in the process we meet a real-life Tony Stark.
Did you miss Day 3? We check out the Bike Shed.
Alright, the last few days have been more about bouncing around London than good motorcycle stuff. But that changes today, because Adam and I are headed a couple of hours west to meet the team behind the Crighton CR700W, an incredibly rotary-powered track bike which offers 220 horsepower and 105 lb-ft of torque (80 of which come on at just 3k rpm) but weighs just 285 pounds dry. That power-to-weight ratio is better than what a MotoGP machine offers (as they weigh a “massive” 346 pounds).
Photo from Crighton.
Remember Tony from yesterday? We liked chatting with him so much that we asked if he’d drive us out to Crighton’s facility and he agreed. I love that the grill of his cab has a Union Jack integrated into it.
The drive took roughly 2.5 hours. I spent most of the time catching up on work emails and trying to write up previous days of this story. Roughly halfway through the trip in what seemed like the middle of nowhere, traffic got backed up for over a mile. Tony explained that we were near Stonehenge so it was tourists slowing down to get a look from the road. When we got closer I understood why, though I don’t understand why the local government hasn’t created some sort of pull-out for people that want to stop so that the locals can get through the area without being held up too badly.
Eventually, we arrived in the town of Semley and got to where the magic happens. The first things to know are that Crighton is a subsidiary of a company called Rotron, and Rotron is the brainchild of Gilo Cardozo, MBE. The bulk of Rotron’s revenue comes from the sale of rotary engines utilized in drone helicopter applications, and Gilo is one of the most impressive people I have met in a long time. We’ll get into that later.
One of Rotron’s employees was driving a lovely Alfa that we didn’t get in the US. The dual headlights are actually one unit that are visually split by the styling of the hood.
It’s a Alfa Romeo GTV Spider with a 2.0L Twin Spark engine. When these debuted in 1995, the coupe version won several awards related to the styling. The convertible doesn’t look as good to my eyes but I personally prefer cars without roofs.
They started us off in a meeting room which has a very cool desk made out of airplane wings.
Adam and I got distracted by a cutaway of the rotary motor which does a great job showing how it spins. If you’re not familar with rotaries, I recommend you check out this video.
Gilo explained that one of the big differences between the Rotron design and what people think of in terms of Suzuki RE-5s or Mazda automobiles is that other companies went with thinner rotors featuring a larger diameter. Rotron uses thicker rotors of smaller diameter as that amplifies the volume-to-surface area ratio and is better suited for racing applications versus Mazda’s rotary cars.
There were a few other highlights in the meeting room, including a 1,200 cc four-rotor motor which is good for 200 peak horsepower (150 hp continuous).
Photo from Rotron.
It’s always a good sign when you see employee bikes as you walk into a building.
But it’s a better sign when you look up and see one of the craziest things you’ve ever encountered! This is the Skybike, a flying sort-of-motorcycle with two counter-rotating propellers underneath.
Gilo showed me a video of this working on his phone, but I haven’t been able to find one online (sorry). Turning the bars like a motorcycle makes the contraption go left/right, but the whole handlebar assembly also tilts forward/backwards and that controls elevation.
One drawback to this design is that the craft does not auto-rotate like a helicopter, and because of that there are certain markets that will not allow it to be sold (there’s an integrated parachute system if things start going wrong).
We went into the offices to find people working on CAD designs for the Crighton engine, rearsets, and triple trees. Then we were taken into rooms where they are manufacturing parts for the Crighton with five and six-axis CNC machines, but I’m not able to share any photos in there. They’re able to handle almost everything with the engine in-house, and they’ve already got plenty of spares lined up.
Adam (left), Gilo (center), and Tony our cab driver (right)
Outside, Rotron has several shipping containers which have been converted into engine testing rooms. On the helicopter engine side, one test is holding the motor just shy of redline for 24 hours straight. Techs there told me that rotaries are great when rpm is varied but keeping a consistent RPM can be stressful, and that a lot of the helicopter usage is basically having the engine at almost full throttle for the entire flight. They’re also able to simulate environments such as being 30,000 feet high. Why would they need to do such a thing? Well, this company’s existence is owed to an adventure that Gilo once embarked on with Bear Grylls to fly over Mt. Everest.
That happened in 2007, and Gilo developed the rotary engine as he felt it was the best option in terms of balancing power and weight. Gilo and Bear launched from the Himalayan foothills and got up to 29,500 feet so they could look down upon the top of Everest! Back home in the UK, Gilo kept evolving his rotary design and created Rotron Power to find commercial applications for it.
There’s so much going on with Rotron that I’d love to share but we should probably focus a bit on the reason Adam and I are here – the Crighton CR700W. The name comes from the man behind the design: Brian Crighton.
In 1984, Brian was a service engineer working for Norton – a year later he was promoted to R&D. He told us that Norton’s management didn’t see much of a future in the 588cc rotary engine they were using in the Interpol police bike, but Brian thought he could get power up from 85hp to 120hp for racing
applications. His bosses didn’t think that was feasible and they discouraged him from pursuing the idea.
So Brian just did it himself at home. Even though he showed up with an engine that dyno’d at 120 hp, management still didn’t want to move forward. So in 1987, Brian took a prototype bike to MIRA Test Track and he cracked 170 miles per hour. That got Norton’s attention, and within a few weeks they had a race bike utilizing Brian’s motor and a Spondon frame. They were rewarded with a win in just their second race…and then things got serious.
One of the greatest wheelie photos of all time – Trevor Nation and Steve Spray throw up the JPS Norton RCW588 race bikes.
Norton’s rotary bikes were quite successful: they dominated the British F1 Championship and the 750cc Supercup (easily beating Yamaha OW-01s and Honda RC30s in the latter series). One of the highlights was Steve Hislop’s win in the 1992 Senior TT – British pride in Norton’s win has led to that victory being voted “the TT’s greatest ever moment.”
Hislop on the “White Charger” raced after JPS’ sponsorship ended. Photo from Wikipedia.
Ian Simpson would win the British Superbike Championship in 1994, but the next year regulators finally succumbed to pressure from other manufacturers who had been complaining that Norton’s rotary wasn’t fairly classified from a displacement standpoint and the engine was banned.
Crighton had actually left Norton in 1990 after the arrival of a new team manager, though he still consulted for the British firm. Brian never gave up on the rotary design, but it wouldn’t be until 2009 when he was able to partner up with Rotron to create the next step.
Obviously the highlight here is the engine, so let’s spend a minute discussing it. Though the model is called a 700, the engine actually displaces 690cc (two 345cc rotors). Max rpm is 10,600 rpm, and peak power is found just under that at 10,500 rpm. Max torque (105 ft-lbs) is delivered at 9,500 rpm, so you can probably tell that this engine is going to spend a lot of its life near the redline. Impressively, at 3,000 rpm the engine still puts out about 80 ft-lbs of torque. It’s compact (340mm in length, 240mm in diameter), there are just three moving parts and it weighs just 52 pounds. Including the 6-speed gearbox and slipper clutch (both made by Nova Transmissions), the engine/tranny weigh just 101 pounds.
The structure of the engine is cast in LM24 aluminum alloy and they are machined in-house. The main eccentric driveshaft is made out of EN36 steel alloy which has been cryo stabilized and hollowed out to allow for water to flow through cooling purposes.
I’ll borrow from Crighton’s website to slightly elaborate on that: “unlike any other motorcycle engine before it, the CR700W’s engine features an internal cooling channel, spark eroded into the core of the main rotor bearing journals. These channels are then liquid cooled via a fully integrated shaft-driven inline coolant pump.”
Photo from Crighton.
The chassis is made from 7000 series alloy and features a single shock. The head stock angle and swingarm pivot points are fully adjustable. Engine oil is housed in the main spars, and the whole thing is derived from Spondon.
Crighton has tapped several big names for components, such as BST for carbon fiber wheels (the prototypes have Dymags on them), Brembo for their Superbike-spec monobloc calipers, and Bitubo (Ohlins is an option) for the suspension.
I absolutely adore the shape of the gigantic exhaust – I forgot to ask how big the diameter of the pipes were but it’s significant. The silencer pays homage to the shape of a rotary cylinder.
Oh, and it shoots flames. You can check out this video for some riding footage, including the sound I’m sure you’re desperate to hear:
Crighton is building 25 examples of the first model, a track-only special that’s handbuilt by Brian himself. The next model will likely be a street bike and will be more “mass-produced”, though that’s obviously a relative term. There’s a refundable 5,000 pound deposit for buyers to show they are interested, and the next step is to pay half of the 105,000 pound price to reserve your place and pick your production number.
Photo from Crighton.
Gilo says that Crighton has had 15 people get that far. There’s a good chance that Iconic will become a US distributor for the remaining models, but that’s a discussion for another day…
I cannot spend enough words trying to convey how impressive Gilo is, and I haven’t even gotten into other companies he operates utilizing Rotron engines. There’s Mako Boardsports, which uses a 100cc Rotron design producing 11 horsepower to propel you atop the water:
Photo from Mako
He’s also developed what I have to describe as…a flying car. We got to see the newest version of his creation, though he asked me not to take photos of it. Right now the public cannot buy it, it’s only being sold to military clients.
I realize just having one photo of the flying car probably raises a ton of questions, so here’s a video that’s really worth checking out:
Long story short: Gilo is the closest person I know to Tony Stark/Iron Man, and I’m very excited to see what the future holds for him. We weren’t able to hear the Crighton run during our visit, but there’s a good chance that Adam and I will be picking one up for Iconic and we’ll see where things go from there!
The office park that Rotron is based at has its own little lunch area, so we grabbed a surprisingly delicious bite.
One of the other companies in the park is called Niwaki, and they import gardening tools (it seems with a focus on tripod ladders) from Japan. I liked the Toyota Land Cruiser that they either use as a shop truck or for display.
Gilo’s nephew also runs a company in the same complex. It’s called Silent Classics and they
electric conversions of classic cars (or non-classics, one presumes). We only stopped here for less than five minutes but I could have spent hours. A quick glance revealed that they were working on several projects, including a Nissan Z (I couldn’t tell you if it’s a 240/260/280 though), an Autobianchi, and even a classic Bentley. Imagine being the person who built this car originally and finding out that almost 100 years later someone else would be retrofitting a completely different type of powerplant.
We originally thought that we would spend about an hour at Rotron. The experience was so fascinating that we ended up spending four times that. But we had to get back to London, so Adam and I hopped back in Tony’s taxi and he started the drive back to our hotel.
On the way, I asked if we could stop in the town of Andover (right off the motorway) so I could get an update to the photo I got with the sign on my last trip (as I am from Andover, Massachusetts):
From when Vy and I were here in 2017
Unfortunately, the driver couldn’t find the sign and I had no idea where it was, so this was the best I got. Not very impressive.
Seeing as we were staying at the Nobu hotel, it made sense to get dinner at the integrated Nobu restaurant once before we left. Dinner was great, though I was amused that the sushi restaurant’s logo looks like the fish is raising a fin in defense and asking the chef to spare him.
I’ve been having a lot of trouble sleeping while here, though it’s made it possible for me to try and get some of these posts up while I’m still on the road (normally I don’t write these stories up until I’m back home). I was having trouble falling asleep today as well, but I think that was just due to nervous energy…tomorrow, we’re finally off to the Isle of Man!
On to Day 5!