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Ripmax phase 5


stewartg
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Okay looked it up. 230 grams.

Dave Woods and I built Phase 5's when the plan first came out. Circa 40 years ago. Dave built his with a rib and balsa sheet wing and I did a foam veneer and glassed wing.

Both planes need nose weight which would be similar to the engine in the Ripmax model. I had three slugs of lead for my plane. 250grms x 3. So in total I could add 750grms of ballast.

Dave's plane was lighter than mine and soared easily in lighter lift. 

I was able to drop the whole trailing edge on the wing on my plane which really helped with the light wind performance. Being able to do that was a novelty then.

If there was moderate lift I would always fly with 1 x 250grms slug in. Good lift .5kg and really big days it would take .750kg. At the time it was the first aerobatic slope soarer to use a thinner wing section. Being an Eppler 374 I think happy to be corrected. It flew relatively fast with the ballast in and was a far superior to the Phase 6. The flaps and ailerons were also large in proportion to the wing chord and this made the ailerons and snap flap very effective. Again due to the commercial nature of the Phase 6 and the constraints of the construction method used the Phase 6 had smaller control surfaces moving over a much greater deflection. 

So the battery at 3,200mah is no issue in this plane. I would suggest due to the built up construction I would fly with the pack in all the time on the slope even if it was not required for propulsion.

I have a local slope which flies an Ahi. I am very tempted to get one as the e-flite would allow me a get out of jail card if the the slope lift went due to sink passing through. Before anyone comments it is not a National Trust site.

Build quality is okay. I believe one of the issues is getting the Ripmax motor for it. There are plenty of 1000kv motors around. It is just well priced.

Once the comp season is over I will get one. Plus they will only get cheaper as we plunge further into recession.

 

 

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6 hours ago, SilentPilot said:

Yeah I've got it now.

Not sure what happened first time around!

Looks good. No way I'd put a 3S 3200 in there though. Why oh why do manufacturers always seem to quote such heavy batteries?

I fly my Radian XL (which also specs a 3S 3200) with a 2200 or 1800.

My Mystique RES has 2x 3S 1800 in parallel, but I'm sure with more stick time I'll move the CG back on that too :)

Don't worry too much about weight on a model like this - as long as cg is ok

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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 ;) 

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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.

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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.

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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. 

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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.

 

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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... 

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