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Old Oct 30, 2011, 07:17 PM
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San Diego, CA
Joined Dec 2006
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I flew the SkySurfer (almost identical to an Easystar except for ailerons, and a crazy incidence angle in the motor mount) again today, with an eye toward seeing how long the batteries would last with this 2835-3900KV motor with the 3-blade Master Airscrew 6x4 prop. Used a 3s 11.1V 2200mAh GensAce LiPo battery.

Launched it at about half throttle, and it climbed out nicely. Did a few full-power vertical climbs (10-15 seconds each), and spent the rest of the tim exactly at half throttle, which lets it climb at a moderate pace. I'd circle around, letting the plane climb, then do some medium loops and rolls to bleed off the altitude. Lather, rinse, repeat as needed. Finally throttled back to zero, glided in and landed, 26 minutes after launch. The battery still seemed to have good power.

Put the battery on charge, and it showed a voltage of 11.07V, which says to me it was quite a bit depleted. I charged it at a 1 amp rate, which is pretty gentle for a 2200mAh R/C LiPo. Later I found that it took 109 minutes at that rate, to reach full charge. So the battery was probably around 2/3 depleted by that 26-minute flight.

So I got 26 minutes out of this 2200mAh 3s LiPo, with that motor and prop, with gentle-to-medium flying with a few full-power climbs thrown in.

Now to put my other three-blade 6x4 Master Airscrew prop on my son's Easystar. it has the same motor etc.

Anybody still think a 2835 3900KV motor is a current hog?
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Old Oct 30, 2011, 07:44 PM
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Joined Nov 2007
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Straight and level

I know you need to check for straight and level flight, but isn't there a tendency upon launch for the EZ to go left like a real plane due to P torque (?) With the ascending propeller? I have some hours in 150's and 152's and you need to ride right rudder upon takeoff to maintain centerline.
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Old Oct 30, 2011, 08:03 PM
I ♥ OpenTX
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Australia, New South Wales, Sydney
Joined Jan 2011
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Quote:
Originally Posted by gocaps View Post
I know you need to check for straight and level flight, but isn't there a tendency upon launch for the EZ to go left like a real plane due to P torque (?) With the ascending propeller?
I've never noticed any significant roll tendencies with my EZ*, and I ascribe that to the relatively small prop and the way it's mounted significantly offset from the roll axis of the plane - it would have to throw around virtually the entire airframe.
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Old Oct 30, 2011, 08:07 PM
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Joined Nov 2007
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H2so4

Thanks for the response. It makes good sends. I've never heard folks here speak of left turning tendencies upon climb out.
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Old Oct 30, 2011, 08:10 PM
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Meant to say sense. Still getting used to the DROID2!
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Old Oct 30, 2011, 08:52 PM
Stantheman
LaGrange, Ky.
Joined May 2004
431 Posts
Quote:
Originally Posted by Flypoppa View Post
TOTALLY OFF TOPIC
 
 

 


God Save the Queen!
 
Agnostic Save the Queen. And how do you say Kate Middleton is HOT in proper English?
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Old Oct 30, 2011, 08:55 PM
Stantheman
LaGrange, Ky.
Joined May 2004
431 Posts
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Originally Posted by Stantheman View Post
Agnostic Save the Queen. And how do you say Kate Middleton is HOT in proper English?
And, she can fly my EasyStar anytime she wants!!!!!!
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Old Oct 30, 2011, 09:40 PM
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Nebraska USA
Joined Mar 2008
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Quote:
Originally Posted by Little-Acorn View Post
What you mean "we", Kemosabe?
(...Pssst - I think we better humo(u)r him - they've been driving on the wrong side of the road for a long time....)

gocaps - Regarding torque effects on the EZ*, I'm thinking since the prop is aft the center of mass, and it rotates clockwise as viewed from the rear, that any torque effect (small as it might be) would tend to turn the plane to starboard (right) rather than left as on a plane with a front-mounted prop spinning the same way.
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Old Oct 30, 2011, 09:54 PM
ancora imparo
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Melbourne, Australia
Joined Jul 2005
6,601 Posts
I would think the effect of the rotating prop blast on the fin would be much more significant than any torque effects given the small size of the motor, large wing area, and high offset mounting??
Quote:
Originally Posted by Zaurak3 View Post
gocaps - Regarding torque effects on the EZ*, I'm thinking since the prop is aft the center of mass, and it rotates clockwise as viewed from the rear, that any torque effect (small as it might be) would tend to turn the plane to starboard (right) rather than left as on a plane with a front-mounted prop spinning the same way.
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Old Oct 30, 2011, 10:13 PM
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Nebraska USA
Joined Mar 2008
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Quote:
Originally Posted by jj604 View Post
I would think the effect of the rotating prop blast on the fin would be much more significant than any torque effects given the small size of the motor, large wing area, and high offset mounting??
I fully agree, but the original question was regarding torque effects including the P-factor of the ascending propeller. As you say, and as we know with our EZ*s in practice, it's too small to cause any significant effects.
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Last edited by Zaurak3; Oct 30, 2011 at 10:25 PM.
Old Oct 30, 2011, 10:54 PM
Just trying to get a nut.
scrtsqrl's Avatar
United States, VA, McLean
Joined Oct 2006
6,430 Posts
Removable Tail mod

Wanted to do this for a long time...finally got around to doing it.

Quote:
Originally Posted by scrtsqrl View Post
Our EZ*'s are transported in a modified underbed box:





I modified my original BWEZ* (currently configured as our super simple trainer) to make the horizontal stab removable. This allows the set-up to lay flat, in an unmodified under bed box. Because of the neater form factor, an unmodified box is significantly stronger, attracts less attention, and transports better. As well, I think I can pack the entire kit, plane, ground station, RC, ground support equipment, and tools all in the same box. This would make things easier, especially when traveling in commercial aircraft charging for each piece of luggage...



It was relatively simple.

1. Remove the horizontal stab. I used a sharp Xacto knife and a bit of twisting. I probably could have used CA remover. But, I did not want to deal with the mess. (This step of course is not necessary if building from scratch).

2. Replace the Multiplex control horn with a standard dubro park flyer control horn.

3. Bend the elevator control wire 90 degrees at the correct length and install a Dubro Micro EZ link connectors.


4. Notch out a flat "step" under the tail so the nylon bolt head sits on a flat surface and is protected from the ground on touchdown.

5. Puncture a hole through the fuselage and the horizontal stab to fit the 2 inch nylon bolt.


6. Dry fit the entire assembly. Note the required length and trim the bolt to the proper length. I used a hack saw then sanded the edges down. Note where the bolt touches the vertical stab and cut out a notch where the bolt can sit snugly. CA the bolt to the vertical stab. This keeps the bolt from spinning and will hold the vertical stab's aft end to the rest of the airplane, assuring lateral stability.

7. I added flat plastic cut-outs made from old credit cards between the bolt and the horizontal stab, as well as the bolt head and the aft fuselage to distribute the loads a bit.




There you have it! Removable tail...One bolt and an EZ clip to disconnect and connect to remove the horizontal stab...takes about 1 minute...


I flew it today, and did not notice anything different.
The question now is: How long will it last?
If it proves to be a durable mod, I'll do the same on my "mission" bird. Fortunately, if it doesn't work out, all I have to do is glue it all back together again...lols....
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Last edited by scrtsqrl; Oct 30, 2011 at 11:06 PM.
Old Oct 31, 2011, 04:41 AM
Me a long time ago
Flypoppa's Avatar
London N.E. UK
Joined Jan 2007
6,095 Posts
Quote:
Originally Posted by Stantheman View Post
Agnostic Save the Queen. And how do you say Kate Middleton is HOT in proper English?
Good heavens... You are talking about a possible future queen.
So you could say...'pleasant to look at'
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Old Oct 31, 2011, 04:48 AM
Fly Like A Thing Posessed!
NightRunner417's Avatar
USA, FL, Fort Myers
Joined Nov 2010
1,777 Posts
My latest FPV flight with the EasyStar. Had a really great time out there, got to chase a car and had two near misses with real live vultures in flight. Took all the best of it and set it to "Fly", by Sugar Ray. Enjoy! :-)

http://www.youtube.com/watch?v=twjr8pVGNCs

Rick NR417
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Old Oct 31, 2011, 07:43 AM
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Nebraska USA
Joined Mar 2008
1,450 Posts
Hey, Rick, YouTube has disabled your audio due to copyright issues.

I don't speak for everyone, but I rather enjoyed your play-by-play commentary better than any music you could replace it with, anyway!

Roger
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Old Oct 31, 2011, 07:44 AM
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53859 Niederkassel, Germany
Joined Sep 2000
18,762 Posts
Quote:
Originally Posted by Little-Acorn View Post
...
So I got 26 minutes out of this 2200mAh 3s LiPo, with that motor and prop, with gentle-to-medium flying with a few full-power climbs thrown in.
...
Anybody still think a 2835 3900KV motor is a current hog?
Yes I do.

Let's assume your 2200mAh pack was 2/3 empty, which means you have used approx. 1.5Ah for a 26 minutes fight. Your average current in this case was 3.46A.

My EasyStar consumes only 2.17A average on a 2s setup:

http://www.rcgroups.com/forums/showp...postcount=6639

Your setup consumes 3s/2s x 3.46A/2.17A = 2.39 times more energy than my setup - and mine is far from perfect.

Jürgen
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