It depends on your definition of "successful".
Biplanes were the dominant type of aircraft for a couple of decades until manufacturing techniques, materials and design knowledge led to fully viable monoplanes.
Even today some biplanes are still in use, e.g. Pitts Special.
The Russian An-2 (Colt) was manufactured for 45 years (a record only recently beaten by the C-130 Hercules), with over 18,000 being made.
- - - - -
A lot of "agricultural aircraft"--crop dusters--are biplanes, and they work well in that application. Grumman designed one called the Ag-Cat that went through many versions (and many manufacturers--crop dusters don't buy new airplanes until the old ones fall apart, and there aren't many people entering the exciting and insane world of crop dusting) and the latest ones are powered by PT-6A turboprop engines.
Biplanes have more lift at lower speeds.
New biplanes are made of aluminium, steel, carbon composites and plastics.
.
biplanes
Biplanes
The Wright Flyer was a biplane.
Yes they are still used
Back in the 'dawn of aviation' everybody used biplanes.
Biplanes are a type of fixed-wing aircraft that feature two sets of wings, one above the other. They were popular during the early 20th century and were used for various purposes including military combat, air races, and passenger transportation. Biplanes are known for their maneuverability and agility, thanks to the lower wing creating greater lift. However, they generally have a lower top speed compared to monoplanes.
Only in museums.
All biplanes have different wheelspans .
Upper and lower wings are on 'biplanes' -this feature offers more 'lift', but also more 'drag'. Many early aircraft were biplanes.