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Winter blues got you down?
Have I got the cure for you! This gem popped up on eBay and would make one hell of a neat Christmas present. For your consideration on eBay is an airsled, powered by Aerothrust. Here’s a walk-around from the seller’s son:
Some of you may be wondering why I’m posting up a sled, given that Common Tread is a motorcycle site, and that’s a fair question. First, when I took my little jaunt across the Midwest this year, I took a detour I didn’t share with you, dear readers. I checked out a really intriguing snowmobile museum in Naubinway, Michigan, and kind of got hooked on snowmobiles (despite the fact I’ve never ridden one and have approximately zero time or nearby land to use one). The second reason is a little more relevant: this airsled came (supposedly) from Molenaar Harley-Davidson. We’ll get to that in a second, but first let’s parse out what this thing actually is.
We’re looking not at a snowmobile but an airsled. An airsled is a vehicle designed to move on snow, but unlike a traditional snowmobile, there is no motorized track. Instead, the whole sled glides on skis and is propelled by that giant propeller you can see on the back.
The power unit was created by the Aerothrust Engine Company, an outfit that made these drive units. They were made from 1912 or 1913 to the mid-20s in Illinois. At some point, the company picked up and opened up shop in La Porte, Indiana, which probably explains how this one ended up in its current situation. (Keep reading, it will make a little more sense shortly!)
Aerothrust made complete units (like their Aero-sled). Some early engine companies, like Harley-Davidson, sold just the power units for handy tinkerers, and Aerothrust did this as well. They were probably best known as an outboard motor manufacturer, but also offered an industrial model called the Pormo. (I’ve seen a single-cylinder Aerothrust engine mounted to the rear end of a bicycle, like they show in their ad. I can only imagine those are an inefficient conversion of power.) The engines are, as you can see, opposed twins, and they are two-strokers.
This particular sled is not an Aerosled. Rather, it’s said to be an Aerothrust motor mounted to a chassis built by Harry Molenaar, who founded Molenaar’s Harley-Davidson, a powerhouse Harley dealer after WWII. Harry set up his shop in Hammond, Indiana, and eventually spread out to a few other shops in that area. (In fact, a photo of him outside his dealership on the then-new 1936 EL was used in the 1936 Dealer Catalog!)
Harry wasn’t just some pencil-pushing parts jockey; he raced Daytona back when it was a partial beach course, and he was a barnstormer and pilot in the Civil Air Patrol, and even built his own half-mile dirt oval, which later received fifth, quarter, and three-eighths mile tracks. It was eventually paved in the 1960s and became the Illiana Motor Speedway. Harry’s whole life was motorcycles; he retired from dealership life in 1991, just a little over eight years before his death.
This airsled has a chassis that may look familiar to a few of you greybeards: it’s built on a Harley sidecar body. It is said to have been constructed in 1936. The seller’s husband reportedly purchased three of these machines in 1972 from Harry's dealership, and used them until two of them were pressed into service as parts donors to keep this remaining unit running. (The owner's widow says her husband also hauled them around on a 1936 VLD. Riding an old flattie in the snow is pretty gnarly in its own right, but riding around with one of these babies hitched to the back is a level of badassery I will sadly probably never achieve.) It appears to my eye that the body was lengthened, but that shouldn't matter; as the seller informs us the skis are made to fold upright so the whole shootin' match can be loaded onto a sidecar chassis!
The general execution looks pretty sound to me, though that engine and prop are cantilevered pretty far off the body and don’t appear to have received additional bracing. The obvious danger of this thing (no cage for the prop?!) isn’t something I’d stress over too much, but I can see how some might. This engine isn't running, and the seller's husband could not find the parts to get it running again. (It presently has no spark. I feel that a good overhaul of the magneto would put into running order in no time.) From what I can see, the sled's not fitted with an exhaust, either. It's unclear if it was run like this, but I'd probably want to fabricate something to hush this thing up if it made its way into my hands. At the time I wrote this, the auction had four bids, the highest of which was $609.99. That seems pretty reasonable to me, especially knowing this engine is pretty rare and somewhat sought-after in the antique outboard world.
Ultimately, if I lived farther north, I’d be all over this. It’s probably not going to sell for a king’s ransom, it’s cool and I could still use antique Harley junk in the winter, and I’d probably have (as I often do) the oldest machine in a gathering of like-minded enthusiasts. I think it’s a cool piece of homemade engineering; a hot-rod for the snow. If nothing else, it’s a good way to take my mind off not being on a bike this time of year.
