Ripmax phase 5

[SilentPilot]

I know heavy gliders can fly well but light gliders can stay up longer in lighter lift.

Even a Nimbus 4 drops its water if the lift dies  

[Baldyslapnut]

I think you are missing the point of this plane.

It has a built in thermal. 

Water ballast is carried on a full size plane to increase the Lift over Drag and thus the glide angle on distance flights. Same with some types of models.  So F3B for example.

A Phase 5 is neither a thermal soarer or a F3B plane. Yes it is possible to fly a lightly loaded Phase 5 in light lift and I have seen very skilled pilots speck this type of plane out of sight on a slope in very light wind. However, you would have more fun with a F3F plane or  similar.

If you had visited the Radioglide event  in May you would have seen heavily loaded F5B planes out climbing F5J planes in thermals despite having a wing loading 4 x times heavier than the F5J.  Wing loading is only one factor to a planes ability to soar in lift.

[SilentPilot]

Water ballast doesn't increase L/D it just speeds things up. You don't need to push the nose down so far to accelerate. 

[f3fman]

47 minutes ago, SilentPilot said:

Water ballast doesn't increase L/D it just speeds things up. You don't need to push the nose down so far to accelerate. 

By not having to push the nose down the wing is flying at a less draggy angle of attack.

[SilentPilot]

If you meant the tail then I could maybe agree! 

[Baldyslapnut]

Reynolds number increases with speed, and the friction drag coefficient goes down. Flying at a higher wing loading means flying at a higher speed regime and at a lower friction drag coefficient, thus better L/D than at the same polar point at lower speed. 

[SilentPilot]

So why not always fly fully ballasted?

[Baldyslapnut]

Well that is a question of preference. Controlled by skill, confidence and the required outcome of the flight

In general for me then yes I fly fully ballasted for the prevailing conditons. How much will depend on the objective of the flight.

So F3F will be controlled by the level of lift and whether there is a cross wind on the course. F3F requires a balance between speed and grip in the turns. The larger the angle of cross wind then ballast becomes a critical factor,

Aerobatics is a balance between gaining height from the available slope lift and energy retention  plus tracking depending on the wind speed.

F5J would be a balance between  the lightest wing loading for thermal and having the ability to gain ground back up wind once the you leave a thermal you may have tracked down wind,

F3B you carry max ballast for speed and distance tasks. Depending on your ability to launch to a good height.

F5B planes have a minimum weight and are small and high aspect ratio so they tend to be close the FAI limit even at the minimum weight allowed .

I always fly with the maximum weight I believe is suitable to the conditions.

 

[SilentPilot]

I'll tell all my friends not to dump ballast anymore when the thermals die.

I'll show them you've found L/D to be better when heavy! 

 

Back to the Phase 5 now if we may... 

[Baldyslapnut]

No more to be said until we get one and try it.