What to put into your flight log:
If you were to go to an indoor model contest, you will see that all modelers have some kind of a notebook to keep records of their models. People use data sheets, notebooks, folders, palmtops, and even laptop computers to keep their records in at the contest. The reason is quite simple. The records give you a quick reference to see how to set up your model, and get it to fly without having to go through trial and error each time you go and fly.
(I have included a basic flight log you can expand on, it is an Excel spreadsheet)
The new rules require at least 6 parameters to keep recorded, but there are actually more than 6 parameters that can be recorded. The SO rules require
1. Motor size (mass, length, and width)
2. Number of turns at launch
3. Flight time.
Then 3 more parameters of your choosing
I typically keep these notes for each flight:
Rubber length: 14.0"
Rubber width: .105"
Rubber weight: 1.98gr
Turns: 1600
Back off turns: 40
Launch Turns: 1560
Flight time: 4:14
Turns left: 290
Was it an official flight? yes
RPM: 300
Comments: Climbed
to roof, hit the ceiling two times, then peaked out just beneath the lights.
Trim was fine, stalled slightly when coming down, may have hit some bumpy
air.
One of the terms you may not understand is back off turns. This refers to turns which you unwind before hooking the motor on the airplane. In the example above, 1600 turns were put into the motor, then 40 turns were unwound, and the measured torque was 15.6. The reason you back turns off is because the torque levels may be too high for the model, either structurally, or simply because the ceiling is too low. In this example, the torque may have been 19.0 after the 1600 turns were put in, but after unwinding 40 turns the torque lowered down to 15.6. The lower torque level means that the model will not climb so fast after launch. If you are flying in a higher ceiling, then you may not want to back off any turns at all, and use the extra torque to gain more altitude.
RPM, or revolutions per minute, is the average rate at which your propeller is spinning per minute of flight time. This is good to know as it gives you an idea as to how much time you can expect to get with your model. RPM is calculated by taking the number of turns used for your flight and dividing it by the flight time in minutes of your flight.
For example:
Number of turns wound in the motor: 1550
Number of backoff turns: 50
Turns left after landing: 150
Flight time 4:30
Used turns = 1500-50-150=1300 turns
RPM = 1300/4.5= 300
Other parameters about your model you should keep track of:
Wing incidence
Stab incidence
Balance point
Wing wash-in
Tail tilt
Boom offset
Amount of side thrust
Amount of down thrust
What batch of rubber you are using (not all rubber motors are created equal)
What size wood you used in building your model
What weight balsa wood you used when making your model
What type of propeller you are using
What is the pitch of the propeller
These things are all important because one day you may accidentally damage your model severely, either by hanging in the rafters of your gym, or by mishandling your model. You may take several hours getting your model trimmed properly, then unfortunately someone may run past your model and the wake from their body can break the tail off your model! So if you have this information written down, you can then read your notes, and glue your tail on the exact way it was before and save yourself lots of time of re-trimming your model.
Additionally, it allows you to know exactly how your model will fly. By keeping good notes, you can always look back at what you did in the past, and reference it as your starting point for today. There are many one day model contests I go to. And these contests may require me to fly over 10 events in a 7 hour time slot. The only way to do this is by referencing my notes for a specific model and then I can start right where I was last time I flew it. Sometimes I keep the same model and rubber motor for years at a time!