First of all a warm welcome here on board of our forum
Do you mean the model in the museum in Brest?
French ship Valmy (1847) - Wikipedia
As known the Valmy was laid down at Brest in 1838 as Formidable and launched in 1847.
and these information are given about the model:
photos of the model:
Category:Scale model of Valmy-MnM 21 MG 4 - Wikimedia Commons
For me it seems, that the ship model was build very early, when the ship was still in the yard under construction. Here the information is given that the model was finished appr. 1840, definitely before 1842!!! At this time the modelers needed also one or two years for such a model, so therefore I guess the models was build based on theoretical (discussions principale)
Very interesting is this info:
She displayed poor performances during her trials, especially with a tendency to roll, and was generally considered a failure. Stability problems were to some extent improved by the addition of a 3 m (9.8 ft) high belt of wood sheathing at the waterline. The outcome of the project led the French Navy to return to a more traditional design with the next generation of ships, which would lead to Bretagne.
Additional Information:
The Valmy is also mentioned in these publications:
LES VAISSEAUX de 74 à 120 canons - Historique 1650-1850" by Jean Boudriot & Hubert Berti
Book Review: LES VAISSEAUX de 74 à 120 canons Historique 1650-1850 by Jean Boudriot & Hubert Berti available directly from ancre in french language, unfortunately in moment no other languages https://ancre.fr/fr/ouvrages-de-base/67-vaisseaux-les-de-74-a-120-canons.html 74- to 120-GUN...
shipsofscale.com
Book review - Book Review: "MODELES HISTORIQUES au musée de la marine - Volume 2"
Book Review: MODELES HISTORIQUES au musée de la marine - Volume 2 by Jean Boudriot The book has 288 pages on the collections of the Museum of the Navy. 359 color photographs. Format 24 * 31 cm Only available in French language – price actual via ancre 95 Euro...
shipsofscale.com
Great work Uwe, you have a talent for providing interesting ship research. 
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