When people discuss the difficulties with the N-1 rocket they frequently cite its 30 engines. (This number was used to help keep the price of the N-1 down.) Certainly no airplane would be fitted with 30 engines. On the other hand the R-7 became a very reliable launcher with its 20 main engines. (After some number of failures during development.) Are 27 engines (Falcon 9 Heavy) just too many? I guess time will tell.