Time to first solo depends on a number of factors:
- The students natural (or not so natural) aptitude
- Previous flying experience (fixed-wing, hang glider etc maybe not hot-air balloons though!!)
- The ability of the instructor(s) to impart the necessary skills
- The type of training course you undertake:
- Full time over a compressed period
- Every weekend
- Every other weekend
- When you can afford it etc
When I was instructing at a commercial school, we took on ab-initio students. All students were picked from fairly new fixed-wing ppl holders. As John Eacott has already said, it is a lot easier to teach the rudiments of general handling in a plank.
If a student did not show signs of going solo by 8 hours, he/she would be put under the microscope and most likely given a change of instructor, at least for a short period, to assess what was the problem. A number of students who went solo in under 8 hours. However, I'm sure that this would not have been the case had they not already had a fixed-wing ppl.
Just noticed in Three Blades posting the reference to helicopter first solos only being a quick hovering exercise. Not the case where I worked, unless you consider the initial hover and landing that we signalled the student to perform before we gave the final thumbs-up to lift into the hover for the second time and perform a complete circuit. The criteria for the decision to send the student? Essentially, apart from the obvious need to be able to control the helicopter accurately and demonstrate safe airmanship, we had to be satisfied that, if the engine failed during the circuit, the student should be able to perform an engine off landing without harming others on the ground (or in the air!!) and be able to walk away from the machine (or what was left of it!!)
Conversely, a number of experienced CPL and ATPL fixed-wing pilots found it very difficult to make the transition to helicopters. Hovering and washing the speed of to zero during the approach were some of the majoe stumbling blocks.