Identification needed

[Varese2002]

Originally Posted by YavorD

Hi Kees,
It is hardly important, but Le Rhône 9C in good condition was able to put 90-92 h.p.!
Regards,
Yavor

Intresting, I have read somewhere (forgot where) that most rotary engines needed complete overhaul / maintenance every five hours of use, hence the large forces of mechanics which were needed.

Regarding the mystery plane the Le Rhône 9-cylinder was technically obsolete in 1917, the time of the Van den Born F5 and totally inadequate to propel this machine. Let alone at full crew strength (5) and MG's (probably 4). The idea is in my head that the project of Van den Born was not taken very seriously by the French military brass

Cheers

Kees

[YavorD]

Le Rhône 9C was actually in high demand as a reliable power source for training machines not only in 1917 but much later. There was a need for a thorough dismantling and clean-up after few hours only, as well as comprehensive overhaul at about 25 to 30 flight hours.



Concerning F series, may be there is another contender, e.g. Dorand Do 1 (pusher version)?

Regards,
Yavor

[Varese2002]

Originally Posted by YavorD

---
Concerning F series, may be there is another contender, e.g. Dorand Do 1 (pusher version)?

Regards,
Yavor

No contender here, this Dorand is mostly identified as the Dorand Armored Interceptor (unfortunately no French name) which was designed on the basis of a 1913 specification for an armed interceptor. Machine appeared in 1914, but disappeared from history almost immediately. No hard facts known. Machine was fitted with two 80 hp Le Rhheône rotaries, pusher configuration with the technical speciality that propellers were connected, sothat when one engine broke down, the other engine could drive both propellers (!). The Dorand DO.1 is a different machine (biplane tractor single engine).

The Van den Born F 5 machine can at least be dated in 1917.

I am working on the known classification, so it is at least known where the mystery F class fits in. Out French friends are surely needed to unravel this

Cheers

Kees

[paolomiana]

Originally Posted by YavorD

Le Rhône 9C was actually in high demand as a reliable power source for training machines not only in 1917 but much later. There was a need for a thorough dismantling and clean-up after few hours only, as well as comprehensive overhaul at about 25 to 30 flight hours.

Hi Yavor, it happens to you to remember where you find these numbers?

cheers

Paolo

[YavorD]

Originally Posted by paolomiana

Hi Yavor, it happens to you to remember where you find these numbers?
...

Hi Paolo!
One of the sources is Gérard Hartmann, Moteurs de légende : Le Rhône, Dossiers historiques et techniques aéronautique française

... le ministère de l’équipement impose à le moteur Le Rhône 9C qui vient de réussir son homologation à 80 ch pendant 15 heures, et dont le temps moyen entre pannes est excellent, supérieur à 30 heures, soit le double des moteurs Gnome.

Le Rhone Instruction Book (about 110 hp 9J)

It is advisable to make a complete examination of the engine after every 30 hours of running.

Regards,
Yavor

[Varese2002]

Back to the F-category as mentioned by Davilla. I did some research in the coding system and unfortunately found a less than complete view of these categories, most likely issued by the S.F.A. [Service des Fabrications de l'Aviation).

The first list describes most likely the introduction in Spring 1916 of aircraft categories in French aviation. The list is quoted in J.M. Bruce. War planes of the first world war Fighters Vol. 4, page 39.



Clearly can be seen that this is a rough classification from A till E, which was probably right for the diversification of aircraft in Spring 1916.

At the end of the war (1917 / 1918) this has evolved into another more complex classification, which according to Davilla (p. 14) at least looks like this:



Missing are the French descriptions of the categories, which surely may link better with the letter code.

Unfortunately their is no mention here of the F category [Fortresse ?]. As the classification is very consistent F 5 surely means a category F machine with a crew of 5 (as mentioned by Davilla). Probably the Van den Born machine was the only machine entered for the class F 5 ever.

Meanwhile the French expert who resurrected the picture of the mystery trimotor triplane has been informed about the findings here till now and he will augment his search in the archives of the SHD A [Service Historique Defense Air] in Vincennes, looking for van den Born and the elusive F category.

I have contacted the BAHA [Belgian Aviation History Association] to get more information about the activities of Charles van den Born between 1916 - 1918. Especially about his elusive F 5 flying fortress machine.

Cheers

Kees

[SCMc]

Could the engine be a Clerget (two rods per cylinder) rather than a LeRhone (one rod per cylinder).

Steve

[Varese2002]

Originally Posted by SCMc

Could the engine be a Clerget (two rods per cylinder) rather than a LeRhone (one rod per cylinder).

Steve

Hi Steve, you may be right, but I cannot verify this on the picture. Power of the Clerget engines was normally far greater than the LeRhone engine.

Report on activities (lest we not forget).

France

Research has started in the SHD-Air archives Vincennes, with a special look at the mysterious F-category ("Fortresse" ?) and on the mysterious Van den Born machine.

Belgium

Research has started in Belgian archives on the activities of Van den Born in the timespace 1916 - 1918. Perhaps something will come out of it regarding the design of the F-category trimotor aeroplane.

The search will continue, with hopefully some wothwhile results.

Cheers

Kees

[Varese2002]

An update

- The research in the French archives have till now not returned any piece of information about this elusive French trimotor triplane, but ..... searching goes on. Somewhere there must be something in the archives about this machine as in late WW1 it was impossible to build an aeroplane without permission of the government and / or military.

- The research on van den Born and specifically the named F 5 trimotor triplane, only quoted by Davilla and the NASM has till now also returned nothing. Search was pointed at the activities of Van den Born during the years 1916-1918 (when the alleged F 5 was built), but till now no information has been found by a Belgian researcher.

The F category is regarded by French specialists as highly dubious. A great pity that Davilla (or the NASM) does not quote any archival source about this machine, which does not make it very trustful.

It would be much appreciated if any hints on identifying this mysterious French trimotor triplane can be given by forum members.

I promise to renew this thread, so it will not silently die down (that is archived)

Cheers

Kees

[Varese2002]

Still no clue or identification for this French tri-engined triplane. Have there in the meantime come any new information?

Cheers

Kees