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Old Sep 26, 2009, 12:47 PM
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Question
problems with the nextstar ep

100% sure on all battery power (radio and plane)
did all the pre flights and 100% sure on the "CG"

set it down- thottled up (o-k so far.)

took 140 yards to get to a labored airborn status.

looked like the plane was trying to weave left and right and at 6' altitude
does a wing-over in the dirt. (new fuselage ordered)

called hobby zone they said sounds severely under powered....as the plane should have went up at 40 yards.

is this a common occurance with this model?

i've elected to add a 3 blade prop of the same pitch a size to cut more wind.
anyone see a problem with this?

i've removed the "pilot assist" mechanism and replaced the reciever with a spektrum AR-7000

radio is also spektrum DX7se
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Old Sep 26, 2009, 01:25 PM
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starzen's Avatar
USA, FL, Stuart
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did you go down in diameter on the 3 blade prop from the 2 blade ?
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Old Sep 26, 2009, 01:55 PM
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Prop on backwards? Don't laugh, it happens. It will still pull the plane forward, just not very efficiently, and with much less thrust than it should be pulling.
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Old Sep 26, 2009, 02:21 PM
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no... I stayed the same size on the prop.

the tekky at hobby zone said it wouldn't tax the motor and esc any worse
and it should provide some addition thrust.

is he wrong?
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Old Sep 26, 2009, 02:23 PM
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Quote:
Originally Posted by rafe_b
Prop on backwards? Don't laugh, it happens. It will still pull the plane forward, just not very efficiently, and with much less thrust than it should be pulling.

i think it was on correct...the zinger logo was facing front.
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Old Sep 26, 2009, 02:56 PM
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Here's a cheapo spring force gauge that you could use to measure static thrust. I have something like this that I use when setting up a model with a power system that I haven't tried out beforehand.

Seems to me, your problem has to be either in inadequate thrust, or improper trim. Another possibility is the takeoff surface; if the plane's wheels are too small, and the surface is rough, it's possible that the plane can't develop enough speed for takeoff. Some of my planes just jump into the air with almost no rolling involved, but there's at least one that demands a smooth surface on which to accelerate for takeoff.

Oh, by the way, your takeoff approach was into the wind, right?
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Old Sep 26, 2009, 03:40 PM
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no wind and 3" wheels .........surface was low mowed grass.

zero to top end seemed o-k just didn't want to get up.
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Old Sep 26, 2009, 04:45 PM
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A 3 bladed prop of the same pitch/diameter will be WORSE than a 2 bladed prop of the same pitch/diameter. Stick with the 2 bladed props unless you wish to overamp your power system and fry it!

Also, are you SURE you're setup properly? And what altitude are you at?
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Old Sep 26, 2009, 06:34 PM
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Which battery are you using? Fully charged?

Glen
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Old Sep 26, 2009, 09:20 PM
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I have got the same plane, and yes it will take a long runway! The runway I fly off of has a down hill slope on it so that helps, but it still takes the whole thing. Other pilots that fly with me give the plane a little lift by lifting their hands like scouping up air under neath it evertime I fly. Do not try to horse this plane into the air, It just does not have that much power and it will stall and roll. Just keep it in a very gentle climb,straight ahead until you get some altitude to it then it flies great at half throttle. Then comes the time to land. This plane is heavy and will come in fast and will take the same amount of runway to get it stopped as it did started!!

Goog luck
Dean
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Old Sep 27, 2009, 12:26 AM
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did you check and make sure that your throttle channel was programed for 100 percent travel? maybe you weren't getting full throttle. just a thought.

Jason
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Old Sep 27, 2009, 12:33 AM
Deletedfor proving Nauga wrong
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Quote:
Originally Posted by mozeppa
no... I stayed the same size on the prop.

the tekky at hobby zone said it wouldn't tax the motor and esc any worse
and it should provide some addition thrust.

is he wrong?
If the original prop was correct for the motor/ESC/Battery system... then the addition of another blade (keeping the original dia and pitch) will add appx 40% more load on the motor... which could overload the motor, which could cause a fire.

When a plane struggles into the air... get the nose down and don't try to force it to climb. By holding the nose up too high you induce additional drag and stall the wing. Even if you had adequate thrust you could cause the plane to behave as you described in the initial post by applying excessive up elevator too early.

And take the speed brakes off. Throw them away. All they do is prevent you from gaining adequate airspeed.
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Old Sep 27, 2009, 12:40 AM
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Note: Hobbico can be clueless about what prop to put on a motor... and they will never admit it.

EG:

Superstar EP. With OEM motor/ESC/battery and prop is a marginal performance aircraft.

Change from the OEM 9X5.5 to a APC 9X4E and the plane will have higher rate of climb and draw less amps.

Longer flight durration AND better performance by reducing pitch...
That is positive proof that the OEM prop is excess load for the motor.

Hobbico tech support recommends against changing the prop...
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Old Sep 27, 2009, 01:10 AM
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Quote:
Originally Posted by fhhuber506771
Hobbico tech support recommends against changing the prop...
Of course they do.. They want to be the hot shots and know everything...
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Old Sep 27, 2009, 01:18 AM
Deletedfor proving Nauga wrong
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Obviously I didn't listen to them...

I sent them my Wattmeter data and explained the flight results... and they still ship the plane with the 9X5.5

The Superstar EP flys better with a 8X4E than the OEM prop... but the 9X4E gives the best results.

You will note that I used a wattmeter as part of my prop testing. When changing props you need the wattmeter reading of the original and the replacement. If the replacement draws more watts you have to cinsider it a fail when you don't have good information about the ESC. Hobbico won't tell you the amp rating of thier ESC in the SuperStar EP...

(safe for 12 volts 20 amps continuous for 10 min. 25 amps for 30 sec. I tested one to failure at 30 amps for 7 sec... no servo load on the BEC... BEC must be disabled above 11 volts)
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