Tip Tuesday: Demo Tips
The Denver Broncos on having a good plan and the right mindset for a demo jump...
Individually, skydivers will choose different types of parachutes for various purposes. Make sure you master the canopy you’re flying at the moment, before changing to a smaller or faster type.
Generally a higher jump number will lead to more experience in flying and landing parachutes, but this does not necessarily mean that the amount of total jumps has an influence on better canopy control. By taking longer breaks from jumping, we lose some feeling for the canopy and for the judgment of ground references. It takes some jumps again, to feel and fly the same as before. Jumping regularly or training in blocks, will give you a great learning experience in shorter time. Judge your own experience objectively and ask experienced skydivers or instructors for their opinion.
Further downsizing will get you into an area where even little mistakes can have painful results
The suspended weight is the factor that influences the wing loading, it has an obvious importance on the choice of canopy size. It’s a mistake to link the total jump number with the wing loading. Obviously less experienced skydivers should use a less loaded canopy compared to higher experienced jumpers. The right choice depends on the individual pilot’s ability to understand the canopy, to handle it safely and to react correctly in cases of emergency situations or difficult landings.
Generally, the wing loading for first time students shouldn’t exceed approximately 0.8 lbs/ft. Beginners should gradually and progressively downsize to max 1.05 lbs/ft and stay with that canopy until demonstrating the skills to safely land the canopy in all situations. Further downsizing will get you into an area where even little mistakes can have painful results. Make sure that you have successfully managed your canopy in difficult landing situations before going smaller.
if you’re flying at a new DZ, at 1,200 ft elevation, 30°C temperature and you’re not current, be aware of your limitations!
Different types of parachutes show a different behaviour on opening. Some designs open slowly, others open faster. The faster the opening and the less progressive, the more physical stress on the jumper’s body. Older bodies tend to heal more slowly! Landing smaller parachutes in no wind conditions often ends up running or sliding off the speed. Not being able to run off the speed can result in a crash landing (we must also take the landing surface into account). Big and high cambered canopies fly less horizontally with more vertical speed on touchdown, which can result in a hard landing.
Air pressure at sea level is higher than at altitude. The higher the elevation, the less performance your canopy will have on landing. For every 1,000 ft of elevation, we lose about 4% of performance. If you are jumping at a drop zone with 3,000 ft ground elevation instead of at sea level, the canopy loses about 12% of its performance. This is about one canopy size difference!
Faster landings with higher loaded canopies need more landing space. Accurate landings are generally easier with a classical design 7-cell, compared to a small 9-cell (or high performing) canopy that flies a long way across the ground.
Make sure that you have successfully managed your canopy in difficult landing situations before going smaller
Normal landing areas on airfields offer a lot of space to land parachutes safely. Looking at an aerial picture and studying the surroundings of the DZ will help you to find alternative landing areas in case of an emergency or off landing. The aerial picture of the landing area can also show us expected areas of turbulence, in different wind directions. Plan every landing respective to turbulent areas.
Cold air has a denser air pressure than warm air. In cold climates, canopies perform better than in warm weather.
Don’t think of a Plan B in the last moment; think about it high up, or better still, on the ground before you jump
Busier drop zones use bigger aircraft. This normally means more traffic over the landing area. First make sure that you’re clear of traffic then fly your planned approach. In case your Plan A approach is not possible, remember your landing priorities and have a Plan B. Don’t think of a Plan B in the last moment; think about it high up, or better still, on the ground before you jump. Stay attentive during your complete flight and landing.
Every location has its typical winds in strength and direction. Knowing about typical winds and possible changes in wind direction at the certain landing spot will help you to work out a Plan B for every landing approach and avoid last second decisions. The more difficult the wind conditions in the landing area, the more careful your approach should be.
As there are different motivations for jumping and flying parachutes, there are different types of parachutes on the market. Most parachutes apart from student, CRW and accuracy parachutes are elliptical or semi elliptical. In most cases parachutes with a higher aspect ratio will have a more elliptical shape and will be more responsive to pilot inputs. The smaller and more elliptical a canopy’s shape is, the better piloting skills are required to safely land it. Some open slower, fly faster or produce more lift. Think about your own motivation for flying parachutes and find the parachute that meets most of your requirements.
Make sure you master the canopy you’re flying at the moment, before changing to a smaller or faster type
Just as the factors here affect your choice of canopy, they also affect the performance of the canopy you choose. For example, if you’re flying at a new DZ, at 1,200 ft elevation, 30°C temperature and you’re not current, be aware of your limitations!
Your classification as a canopy pilot in three steps:
Note: This is just a guide and should be taken in conjunction with reading the limitations and variables above. Tables for 9-cell, ZeroP canopies at sea level. For 7-cell canopies, downsizing one size is acceptable. At elevated DZs, add 4% to the canopy size per 1,000 feet elevation
Text and diagram created originally by Reiner Bos for the Safe Flight School canopy course manual
To work out your current wing loading there is an easy calculator here. This will allow you to quickly work out new values for if you're wearing weight or you're considering an upsize or a downsize. Caution – as with the above graph the classifications (intermediate, advanced, etc) include being current.