*Updated* With more information about the Fiat engine at the bottom of the post.
Since this is The Old Motor, anytime an interesting photo of an old engine of most any type comes across our desk, we are apt to post an image of it here. Early aviation in France was quite advanced for the time and this led to the development of many interesting engine designs, some of which later found the way into the automobile.
Marcel Hanriot can be seen above posing for a picture in a 1911 Hanriot Militaire Triplace Type VIII which utilized a very interesting Clerget engine. The aircraft was built by the Aeroplanes Hanriot et Cie, run by his father Rene Hanriot, who was also an early automobile racer.
The occasion was a French military competition held at Reims in 1911, which was organized by the Army to learn more about the aircraft available at the time and to also test them in competition. Hanriot’s craft was passed over at the trials because the fuselage was very slender and open which left the crew unprotected.
The machine was also a bit dated and never had a serious chance against some of the other more modern contemporary machines. You can view more photos of the aircraft built by them in a history of Marcel Hanriot’s early flights by Gerard Hartmann. The photo was found via Isabelle Bracquemond and it is courtesy of Early Aviation.
Moteur Clerget Type 4W, 100 HP – Detail of rocker arms and conical valve springs – Moteur Clerget 200 HP V-8
The French National Museum has a number of early airplane engine images in their collection and information about the Clerget engine was found there. A photo of a Moteur Clerget Type 4W 100 HP, as used in the Hanriot craft, can be seen just above on the left. In addition to it, images of two different Moteur Clerget 200 HP Type V-8 engines were also located and give us a clear view of the very interesting OHV gear used by the maker.
The Clerget engine valves are actuated by one substantial single rocker arm and pushrod assembly per cylinder that operates both valves. One detail to note is the interesting design of the conical shape, flat section coiled valve springs which can be seen in the center photo above. This is just one of many different experimental types of valve springs that were tried in the early development of the poppet valve engine. One of this type of engine has survived in the Science Museum in London.
And finally above, also found in French National Museum collection is a 1908 Fiat 50 HP OHV V-8 air-cooled aircraft engine that ranks as one of the most interesting and attractive engines we have ever seen. None the details about it are known about it, so if you can enlighten us please do. Look for more interesting engine photographs from the collection soon.
*Updated* Thanks to reader Mark Walker from the UK we now have full details of the Fiat aero engine that can be seen below. The list of all previous Fiat automobile racing engines appears to point to the fact this engine was built for aircraft use only.
Below is a video showing a popular model of the Deperdussin monoplane that shares many of the design characteristics with the larger Hanriot. It was produced in quantity and reportably was a great improvement over the earlier Bleriot type machines. This is an original machine that has been is in the Shuttleworth Collection since 1935.