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Old Sep 13, 2010, 11:38 AM
Build 'em break 'em fix 'em
chinaclipper63's Avatar
Joined Oct 2009
439 Posts
Mock up??

Quote:
Originally Posted by modfly View Post
[B] Its best to mock the plane up first to get everything balanced COG wise.
?? How do you do THAT? Mock up??
Inquiring minds want to know!
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Old Sep 13, 2010, 12:45 PM
Doing it in the Lateral Axis
modfly's Avatar
USA, OH, Akron
Joined Dec 2006
15,360 Posts
Quote:
Originally Posted by chinaclipper63 View Post
?? How do you do THAT? Mock up??
Inquiring minds want to know!
In a mock build, you position everything with clear tape, 2 sided tape and rubber bands then check the balance. If needed, re-position so that balance is achieved.

Do not use dead weight! There are many ways to get COG without adding dead weight.

A key factor is the lipo mount. The lipo can be mounted forward and Vertical just behind the motor to achieve proper forward balance.

These planes were designed for a heavy brushed 130 motor and a 6 cell ni-mh pack so everything needs to be as far forward as possible when using a BL motor and small lipo.
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Last edited by modfly; Sep 14, 2010 at 12:21 AM.
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Old Sep 13, 2010, 05:29 PM
Suspended Account
Κύπρος, Λευκωσία, Πέρα Χωριό
Joined Jan 2010
9,530 Posts
Ilike it..
My corsair is still in the box.. my 2.2g aileron servos are flying home right now so Id prbably start building it during the next weekend
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Old Sep 13, 2010, 07:02 PM
Airplane Killer
SumthinsFishy's Avatar
Orange County, CA
Joined Oct 2009
1,725 Posts
Quote:
Originally Posted by chinaclipper63 View Post
<snip>
Is there a better way to add weight?
<snip>
Ideas?
Not sure how they fit but coins are cheaper than lead. A nickel weighs 5g, a penny 2.5g, and quarter 1/5 oz...
Dave
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Old Sep 14, 2010, 08:33 PM
Not enough hours in the day
Slaanesh's Avatar
Melbourne
Joined Feb 2009
2,429 Posts
Quote:
Originally Posted by chinaclipper63 View Post
?? How do you do THAT? Mock up??
Inquiring minds want to know!
This is what I did:

Mount all the items and do all the construction work that can be done. Ie. the motor and aileron mods if you are doing that. Remove unnecessary foam, You can take away a lot at the front especially if you are not using the stock brushed motor.

Do a dry run assembly of the rest of the model. Use double side foam sticky tape cut out into squares.
Temporarily stick the components in place in the approximate location within the fuselage, including canopy, propeller, spinner, pushrods - EVERYTHING that you are using.

Test the COG with ALL the components in place. Move them around until you achieve the right balance.

You don't have to add any extra weight using this method.
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Old Sep 14, 2010, 11:23 PM
Registered User
will3kgt's Avatar
Grand Blanc, MI
Joined Jan 2007
481 Posts
Here's a vid of my Zero.
Brushless Gravity Hobby ZERO (6 min 17 sec)
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Old Sep 14, 2010, 11:26 PM
Registered User
will3kgt's Avatar
Grand Blanc, MI
Joined Jan 2007
481 Posts
Quote:
Originally Posted by chinaclipper63 View Post
Today was to be the day.
I chose a place that had a nice expanse of grass and prarie.
The wind was 0-5mph, out of the West
The sun was setting in the West.

I had to put about 21g in the bottom of the nose (on the plastic nose protector). It seemed to balance OK at the suggested COG, maybe a smidgen tail-heavy?
I put the battery in, pushed a little foam block I made to keep everything forward, and closed her up.

First I had to do the range check, walked about 60 paces, no problems. So far so good. I wanted to launch into the wind, so I found a nice grassy area, brought up the RPMís, and tossed her up.

A little lurch to port, but she evened out with minimal control from me and she was flying!
My idea for the maiden was to get her up, trim her out, then land.

Success!

I brought her back around, dialed in a bit more down elevator, a little rudder trim, and there we were.
She looked pretty cool too, with the setting sun as a background. I flew high, but tried to avoid looking directly into the setting sun.

After about 2 or 3 courses, it was time to land. As I brought her around for the base and when I turned into the final, sure enough, tip stall. Right into some tall grass. No harm, no foul I thought, so I decided to put it up again. It took off much smoother, and the second flight was almost 10 minutes long.

It took a few minutes getting used to the bird, but she flew pretty good. I noticed some fluttering on turns, and couldnít quite figure out why. All and all, a good flight. Brought her in, and this time took a bit more altitude on the base, made the turn, and landed nicely in the weeds. No gear on this one!

For the next flights, I thought I would try the bigger (6x3) prop. Again, she took off nicely, got another good 10-12 minutes out of my 18C 350mAh power source. Still had that little fluttering, and I noticed loops were difficult, as she would just tend to almost roll instead of loop. No worries, I had another great flight, and brought her in. For the next flight I tried my old Mini Super Cub battery pack, a 7.4 300mAh jewel. Itís a bit wider, so I couldnít slide it as far forward. I tempíed a 1/4oz weight under the nose, and she flew like a champ!

It was a good day. A successful maiden, and great conditions. When I got home, in the post flight inspection (you know you all do it) I noticed the right half of the elevator was loose. It was not moving with the left half. Well, that answered THAT problem. I will affect the cure for that immediately.

Summarizing, these little birds are fun! Fun to build; I am already planning another one. Good work Gravity Hobby, and some day soon, I will try and get that hulk up, that 8oz 4 channel BEAST I have been writing about.
Cheers!
Good deal. My Zero has a 19gm brushless motor and I'm running an 2S 800Mah battery.
Brushless Gravity Hobby ZERO (6 min 17 sec)
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Old Sep 15, 2010, 02:35 PM
Crashing but learning...
Wildweasel09's Avatar
Brazil, S„o Paulo, Sao Paulo
Joined May 2009
463 Posts
Just joining the group now !

Gravity Hobby is the best place to buy models with the right price ! (I have the Cargo Transport, that I modified with cargo door, lights, LG, flaps doing parachute launches, very good plane, hope they start to sell it again, and recently, I've tested the Skylark Helicopter, You can see the videos in my blog).
Now the Zero is my first Gravity Hobby warbird, I'm using one 300mah eflite battery, nano motor 14g 1600kv, 10a esc and gws prop 5030x3. Didn't resist to do something different on the zero, the pilot moves his head and I left the cockpit opened!
Will produce some videos later! Here is some pictures:
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Old Sep 15, 2010, 05:49 PM
Doing it in the Lateral Axis
modfly's Avatar
USA, OH, Akron
Joined Dec 2006
15,360 Posts
nice plane and I really like the Landing gear. Does the tail wheel steer?
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Old Sep 15, 2010, 06:03 PM
Crashing but learning...
Wildweasel09's Avatar
Brazil, S„o Paulo, Sao Paulo
Joined May 2009
463 Posts
Quote:
Originally Posted by modfly View Post
nice plane and I really like the Landing gear. Does the tail wheel steer?
Thanks, Modfly and yes, the tail wheel steers, coupled to the rudder through a piece of tube and wire.
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Old Sep 15, 2010, 06:54 PM
Registered User
will3kgt's Avatar
Grand Blanc, MI
Joined Jan 2007
481 Posts
Quote:
Originally Posted by Wildweasel09 View Post
Just joining the group now !

Gravity Hobby is the best place to buy models with the right price ! (I have the Cargo Transport, that I modified with cargo door, lights, LG, flaps doing parachute launches, very good plane, hope they start to sell it again, and recently, I've tested the Skylark Helicopter, You can see the videos in my blog).
Now the Zero is my first Gravity Hobby warbird, I'm using one 300mah eflite battery, nano motor 14g 1600kv, 10a esc and gws prop 5030x3. Didn't resist to do something different on the zero, the pilot moves his head and I left the cockpit opened!
Will produce some videos later! Here is some pictures:
Very nice Wildweasel. Can't wait to see the vids.
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Old Sep 15, 2010, 09:15 PM
Crashing but learning...
Wildweasel09's Avatar
Brazil, S„o Paulo, Sao Paulo
Joined May 2009
463 Posts
Quote:
Originally Posted by will3kgt View Post
Very nice Wildweasel. Can't wait to see the vids.
Thanks Will3kgt !
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Old Sep 15, 2010, 10:05 PM
Build 'em break 'em fix 'em
chinaclipper63's Avatar
Joined Oct 2009
439 Posts
VERY very nice!!

Quote:
Originally Posted by Wildweasel09 View Post
Just joining the group now !
Nice! Best THE BEST GH Zero I have seen. Very cool mods!
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Old Sep 15, 2010, 11:07 PM
Registered User
Brisbane Australia
Joined Sep 2009
34 Posts
Hi Mark here from Australia. Is there any way we non-USA people can buy these great sounding little planes? The Ebay link appears to have disappeared and the Gravity store is not accessable. Any advice?
regards
Mark
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Old Sep 15, 2010, 11:23 PM
CV-15 VB-16
giuseppi's Avatar
USA, TX, Friendswood
Joined Jul 2007
1,385 Posts
Hey, Mark.

These from HK look like the same airframes, and the motor, servos, a battery and esc are included.

Here's the P-40 link :

http://www.hobbyking.com/hobbyking/s...g_Servo_&_LiPo

There's also an Me-109 and a Spitfire.
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