A method for producing a propulsion nozzle wherein the nozzle is produced from a phenolic resin obtained at least by carrying out the following step: a) pre-polymerization of an aromatic aldehyde compound with a phenolic compound in order to obtain the phenolic resin, the aromatic aldehyde compound having one or other of the following formulae A and B: the aromatic aldehyde compound being polyfunctional and formulae A and B being such that n 1 is an integer between 0 and 4 and when n 1 is greater than or equal to 2, the substituents R 1 are identical or different, n 2 is an integer between 0 and 5 and when n 2 is greater than or equal to 2, the substituents R 2 are identical or different and n 3 is an integer between 1 and 6, and formulae A and B being such that the substituents R 1 and R 2 are chosen independently from one another from: -OH, -COOH, -CHO, the groups -O-Alk wherein Alk denotes a substituted or unsubstituted alkyl chain of 1 to 4 carbon atoms, saturated or unsaturated, substituted or unsubstituted hydrocarbon-based chains comprising between 1 and 20 carbon atoms, optionally interrupted with one or more heteroatoms, and optionally having one or more carbonyl or carboxylic acid functions, substituted or unsubstituted, monocyclic or polycyclic, saturated, unsaturated or aromatic carbocyclic or heterocyclic groups optionally having one or more carbonyl or carboxylic acid functions, and substituted or unsubstituted aryl groups optionally having one or more carbonyl or carboxylic acid functions, R 2 possibly also denoting a radical of formula A1 in formula A above or a radical of formula B1 in formula B above and R 1 possibly also denoting a radical of formula A2 in formula A above, formulae A1, A2 and B1 being the following: in formulae A1, A2 and B1, R 1, R 2, n 1, n 2 and n 3 are as defined above. a) pre-polymerization of an aromatic aldehyde compound with a phenolic compound in order to obtain the phenolic resin, the aromatic aldehyde compound having one or other of the following formulae A and B: the aromatic aldehyde compound being polyfunctional and formulae A and B being such that n 1 is an integer between 0 and 4 and when n 1 is greater than or equal to 2, the substituents R 1 are identical or different, n 2 is an integer between 0 and 5 and when n 2 is greater than or equal to 2, the substituents R 2 are identical or different and n 3 is an integer between 1 and 6, and formulae A and B being such that the substituents R 1 and R 2 are chosen independently from one another from: -OH, -COOH, -CHO, the groups -O-Alk wherein Alk denotes a substituted or unsubstituted alkyl chain of 1 to 4 carbon atoms, saturated or unsaturated, substituted or unsubstituted hydrocarbon-based chains comprising between 1 and 20 carbon atoms, optionally interrupted with one or more heteroatoms, and optionally having one or more carbonyl or carboxylic acid functions, substituted or unsubstituted, monocyclic or polycyclic, saturated, unsaturated or aromatic carbocyclic or heterocyclic groups optionally having one or more carbonyl or carboxylic acid functions, and substituted or unsubstituted aryl groups optionally having one or more carbonyl or carboxylic acid functions, R 2 possibly also denoting a radical of formula A1 in formula A above or a radical of formula B1 in formula B above and R 1 possibly also denoting a radical of formula A2 in formula A above, formulae A1, A2 and B1 being the following: in formulae A1, A2 and B1, R 1, R 2, n 1, n 2 and n 3 are as defined above. the aromatic aldehyde compound being polyfunctional and formulae A and B being such that n 1 is an integer between 0 and 4 and when n 1 is greater than or equal to 2, the substituents R 1 are identical or different, n 2 is an integer between 0 and 5 and when n 2 is greater than or equal to 2, the substituents R 2 are identical or different and n 3 is an integer between 1 and 6, and formulae A and B being such that the substituents R 1 and R 2 are chosen independently from one another from: -OH, -COOH, -CHO, the groups -O-Alk wherein Alk denotes a substituted or unsubstituted alkyl chain of 1 to 4 carbon atoms, saturated or unsaturated, substituted or unsubstituted hydrocarbon-based chains comprising between 1 and 20 carbon atoms, optionally interrupted with one or more heteroatoms, and optionally having one or more carbonyl or carboxylic acid functions, substituted or unsubstituted, monocyclic or polycyclic, saturated, unsaturated or aromatic carbocyclic or heterocyclic groups optionally having one or more carbonyl or carboxylic acid functions, and substituted or unsubstituted aryl groups optionally having one or more carbonyl or carboxylic acid functions, R 2 possibly also denoting a radical of formula A1 in formula A above or a radical of formula B1 in formula B above and R 1 possibly also denoting a radical of formula A2 in formula A above, formulae A1, A2 and B1 being the following: in formulae A1, A2 and B1, R 1, R 2, n 1, n 2 and n 3 are as defined above.