The Aermacchi with a Trailer

 

Another Successful Aermacchi

(Even if it never flew!)

By the GAVS Turin section

When we first got the news about the chance of restoring an Aermacchi of the early post-war period, designed by Dr. Bazzocchi, with a tricycle wheel arrangement and two side-by-side seats, we all thought about the delightful and eternal M.B. 308 aircraft (one of which, registered I-BIOH, is still flying today in Turin).

Later, when we got more information, even though the names of the company and the designer matched, it became clear that the object of the restoration was very different from an airplane. It was in fact a Macchitre M.B.1, that is, a sort of tricycle...(excuse me!): it should be properly called a “Three-wheel truck with trailer towing capabilities,” (in Italian: Autocarro a tre route con possibilità di rimorchio), as Aermacchi’s advertisement pompously described it at the time.

A new adventure began for our group. After all, the M.B.1 three-wheel truck was a product of an aeronautical company, and it was designed by a very famous Italian aviation designer. But among the members of our Turin group of aircraft restorers there were very different reactions, ranging from perplexity to open dissention, from members who were open about the idea of restoring the truck to others who disagreed and pointed out our lack of specific experience. The one who finally resolved the issue was Bruno Doria, who had already done an excellent restoration of a WWII Willys Jeep, and declared: “If you guys don’t want to do it, I will! Even if I had to do it alone!”   

So we obtained the documentation and we began to examine the vehicle, which is certainly unique.

The M.B.1 arriving at the group's shop

The M.B. 1 presents a refined and streamlined shape, with a finely rounded nose, and a split windshield with two rearward-angled glass panes (some say that Dr. Bazzocchi was inspired by the Douglas DC-3’s nose).

We began the work, disassembling the main component, and right away Bruno Doria took the engine home, so that he could more easily work on it.

There were surprises from the beginning. After herculean efforts to remove the wheels, we realized that the bolts of two of them were threaded leftward (except for the rear right one), because the wheels were to be mounted left of the centerline (as in the much fancier Lancia sedans of the time!). A small “S” was etched on the head of the bolts, but nobody had noticed it!

The fancy bolt with the S etched on it  

Since the M.B.1 was the product of an aviation company, welding was reduced to the essential minimum, while rivets abounded. Luckily, all the components of the three-wheel truck came from the FIAT cars that were in production at the time. That made it easy to find extruded metal parts, gaskets, and various accessories, including the single arm of the windshield wiper, (God bless antique cars restorer!)

The main structure of the M.B.1 consists of a cm 10 (4 in.) diameter steel tube that runs through the entire length of the vehicle. Starting from the rearmost point, it carries the trailer hitch, then it runs horizontally to the rear wall of the cabin, where it slants upward about 15° to end below the dashboard. At its forward end, the tube supports the steering gearbox and the front suspension, consisting of a telescopic fork, similar to the landing gear of an airplane, with twin stabilizing and anti-twisting compasses.

The engine, which was also designed by Dr. Bazzocchi, was placed right below the cabin. It is a cc 750 (about in³ 46) horizontally opposed two-cylinder engine, hanging from the center steel tube by two brackets, so it is easily accessible for maintenance, as the owner’s manual reads. However, the manual does not say that the bottoms of the seats had to be flipped up to reach the cylinder heads.

The position of the engine probably guaranteed some welcome heat in the winter, but what about in the summer? No problem! Two large forward air scoops insured a cooling flow of air that vented from the rear window of the cabin, that could be opened for maximum comfort (a relative concept, in the Italian immediate post-war period).

Worth mentioning are the carburetor, because it was the same as in the Lancia Aprilia, and the four-plus-low-gear transmission, which was another Dr. Bazzocchi’s stroke of genius that allowed this unique vehicle to climb everywhere with a manufacturer-declared 1.5 metric ton load (but according to one of our members, who drove one for years, the M.B. 1 could carry anything that fit in it, even twice that weight!)

The restored interior of the M.B.1

Behind the cabin, the tubular frame is integrated by a rectangular steel extruded U bars frame that supported the all-wood bed of the truck (which was the part of our M.B.1 that had suffered the most for the passage of time), and the rear double-leaf spring suspensions.

Unfortunately, the COVID epidemic slowed down our work considerably; but Bruno Doria’s son, with the help of a friend, was able to complete the complex rebuilding of the engine. One very worrisome thing was the presence of two irremediably-seeming stuck engine valves, that resisted any unblocking effort. The solution was the immersion of the engine for twenty-four hours in a cocktail of isopropyl alcohol and Coca Cola. Problem solved!

The final painting was carried out by the Leonardo company, using as a sample a few paint chips retrieved from under the front company badge. The result was a blue that is maybe too shiny, with respect to the original, but very pleasant.

After the assembly of all the mechanical parts, our M.B. 1 was test driven very successfully indoors (Dr. Bazzocchi must have surely breathed a sigh of relief).

This very original vehicle was built in many versions, including a diesel-powered one that had, more or less, the same power, but took advantage of better fuel efficiency and lower cost of fuel.

When aircraft production resumed at Aermacchi, the building of the M.B.1 was first entrusted to the associated company Aermacchi Harley-Davidson (that produced the famous motorcycles with a single tube frame with the engine hanging from it). Then production passed to Bremach and finally to Hansa spa (with a different engine), where the career of the M.B.1 ended after thirty-five years, and more than 70000 three-wheel trucks produced.

This article was originally posted on the n.134 issue of the Ali Antiche magazine, which is a publication of the Gruppo Amici Velivoli Storici, an Italian association of people dedicated to the preservation of the Italian aeronautical heritage.

Your comments, as usual, will be greatly appreciated.

Thank you,

L. Pavese