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Old Aug 18, 2011, 01:56 AM
Cosa Nostra EXP
Exsocio's Avatar
Desio (MB - Italy)
Joined Apr 2007
325 Posts
Quote:
Originally Posted by hercdriver7777 View Post
Here is a good way to check CG and Incidence and Thrust Angle with nothing but the plane itself by flying it.

1. Trim the plane to fly right-side-up at about 1/4 to 1/2 throttle perfectly straight and level so that if you take your hands of the stick it does not climb or dive. Then test it into the wind and downwind to verify your trim.

2. Turn the plane inverted with the EXACT SAME THROTTLE SETTING. If it climbs inverted then you have a tail-heavy condition (go with that assumption for now). If it dives to the ground inverted then it is nose-heavy.

3. Move the battery until the plane neither climbs or dives upright or inverted when trimmed for the same throttle setting.

4. Now that you have a baseline setting for trim we can check CG through the entire airspeed range with a dive test. Take the plane up very high and slow it down to a stall with the throttle at zero. Drop the nose so that the plane is pointing straight down, leave it at zero throttle and take your hands off the sticks. As the plane accelerates with the motor off it will pass through the entire trim speed range and you will discover one of 4 things.

A. The plane will pull to the canopy meaning that you are actually nose-heavy and that you need to adjust your thrust line UP because in step one you trimmed the plane out under power and in step 4 you tested it power off.
B. The plane will pull to the gear meaning that you are actually tail-heavy and that you need to adjust your thrust line DOWN.
C. OR, the plane will one thing at one airspeed and another at the faster airspeed. One example would be when it starts the dive and is going very slow it tucks to the gear but as it accelerates it straightens out and finally
pulls to the canopy. This situation is going to be some result of incidence problems and you should bust out a incidence checker and straighten it out.
D. Finally, if the plane goes straight as an arrow all the way to the ground you have no issues.

One note here is that you should do this dive test multiple times to verify your results and you should also do it in different relative positions to the wind. Another thing to consider is that you should try the dive test once where you bump the elevator in one direction and let it center and then again in the other direction and let it center to make sure you do not have centering problems with your elevator servo. I have seen a lot of "CG" problems from sloppy linkages or bad servos.

Hope that helps!

Good flying!
This is great, useful info!

printed! it goes right in the TX case!

Thank you Herc for sharing.
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Old Aug 18, 2011, 08:31 AM
Epoxy & CA Investor
DenverJayhawk's Avatar
United States, CO, Denver
Joined May 2010
2,574 Posts
just to confirm, pull to canopy when in the nose down position means it's trying to pull itself out of the dive and eventually end up in upright, level flight, yes? Tuck to gear is just the opposite and will try to end up in inverted level flight.
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Old Aug 18, 2011, 09:26 AM
Team Extreme! Team Twisted!
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Columbia SC
Joined Feb 2005
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Correct
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Old Aug 18, 2011, 10:08 AM
Registered User
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USA, IN, Fishers
Joined Jul 2007
762 Posts
Quote:
Originally Posted by N_O_V8_R View Post
mbritt
I took some measurements for you.

If you measure the vertical angle from the top ply on the motor box down to the bottom ply (battery tray) I get zero thrust angle.

Measuring from the side ply of the motor box I get 1.5 - 2 thrust angle, depending on where I measure it.

Of course, this assumes your motor box is straight forward of the cowl ply, but you should be able to tell by looking at the battery tray

Hope that helps!
Wow thanks, about 2 degrees sounds about right. Thank you everyone for the input. Haven't had a chance to do the adjustments yet. You know how it is life has been in the way. LOL. I will make them tonight and see where it goes. Thanks to everyone for all of the good input!
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Old Aug 18, 2011, 10:15 AM
If it hovers I fly it.
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Canada, BC, Vancouver
Joined Jun 2010
130 Posts
YAY! After being away a few days got my flights in this morning. Looks like I got my CG on now. One thing that suprised me was at nice low speed it basically wants to auto harrier... lol. No idea if thats normal or not but its sure cool!

Anyway cannot be happier with how she flies now. Thanks to the board for all its guidance! Now to start pushing it more and more. Ok.. push ME more and more.
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Old Aug 18, 2011, 11:09 AM
OOPS
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USA, GA, Cochran
Joined Jun 2008
20,153 Posts
Quote:
Originally Posted by N_O_V8_R View Post
Sweet video!
I already have a 1/2 dozen 4s turnigy 2650 Nano's, rated 20-50c for the plane.
Not sure how they would compare to your G-Force Batt's.
Any wattage numbers for these setups?
Flight times?

Manta1
What prop, bat. & esc are you running with your setup?

Is everyone using an idle-up with their setups?
Anyone having sync problems with the airboss/torque setup like we are experiencing with the 60" exp's? I need five extra clicks of trim after the prop starts to be safe.
I'm gonna run the motrolfly receiver. 60amp. 13x6.5 prop illnplay with and the 14x7 as well. I had the 950 on the edge and ran 12x6 for 4s and 14x7 for 3. My batts for the mxs will be 4s 2600 Ish
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Old Aug 18, 2011, 12:01 PM
Registered User
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USA, IN, Fishers
Joined Jul 2007
762 Posts
Quote:
Originally Posted by N_O_V8_R View Post
Torque motor still on B/O. Don't know if I can wait any longer!
I have a Hacker 55 amp ESC laying around, so what is the best alternate motor I can put in this thing that will fit the existing motor plate?
A30-14L v2
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Old Aug 18, 2011, 01:32 PM
TEAM EXTREME FLIGHT
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USA, FL, Largo
Joined Dec 2005
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Quote:
Originally Posted by Manta1 View Post
I'm gonna run the motrolfly receiver. 60amp. 13x6.5 prop illnplay with and the 14x7 as well. I had the 950 on the edge and ran 12x6 for 4s and 14x7 for 3. My batts for the mxs will be 4s 2600 Ish
That thing is gonna be sick on 4s.
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Old Aug 18, 2011, 02:16 PM
OOPS
Manta1's Avatar
USA, GA, Cochran
Joined Jun 2008
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Yup. I like sick. Kinda matches me. Sitting in dr office now with 100.9 temp. Doc you give me your flu over the phone?
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Old Aug 18, 2011, 03:26 PM
Justin S
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United States, NC, Mt Holly
Joined Nov 2010
154 Posts
Just ordered one of these to replace my 48" Edge-EXP that will either be sold or crashed very soon I couldn't wait any longer.
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Old Aug 18, 2011, 05:13 PM
Registered User
USA, NE, Waverly
Joined Feb 2011
287 Posts
Quote:
Originally Posted by Brubache View Post
YAY! After being away a few days got my flights in this morning. Looks like I got my CG on now. One thing that suprised me was at nice low speed it basically wants to auto harrier... lol. No idea if thats normal or not but its sure cool!

Anyway cannot be happier with how she flies now. Thanks to the board for all its guidance! Now to start pushing it more and more. Ok.. push ME more and more.

Night and day difference than the "Skywing" MXS, isn't it?
Can't wait to get mine in the air.
I see the back-order on the motors has been lifted.

You have to get a 60" next - just love my 540T EXP. Rock solid.
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Old Aug 18, 2011, 05:14 PM
TEAM EXTREME FLIGHT
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USA, FL, Largo
Joined Dec 2005
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Quote:
Originally Posted by Manta1 View Post
Yup. I like sick. Kinda matches me. Sitting in dr office now with 100.9 temp. Doc you give me your flu over the phone?
No, if you got the flu I had, you'de be sitting in the bathroom instead of the doctor's office.
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Last edited by Doc Austin; Aug 18, 2011 at 05:22 PM.
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Old Aug 18, 2011, 06:17 PM
If it hovers I fly it.
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Canada, BC, Vancouver
Joined Jun 2010
130 Posts
Quote:
Originally Posted by N_O_V8_R View Post
Night and day difference than the "Skywing" MXS, isn't it?
Can't wait to get mine in the air.
I see the back-order on the motors has been lifted.

You have to get a 60" next - just love my 540T EXP. Rock solid.

Um ya. Totally. this thing flies like a proper airplane lol.
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Old Aug 18, 2011, 08:06 PM
Team Extreme Flight, JR, BandE
Georgetown, IN
Joined Dec 2003
1,731 Posts
Quote:
Originally Posted by Doc Austin View Post
No, if you got the flu I had, you'de be sitting in the bathroom instead of the doctor's office.
TMI Doc.
Jeff
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Old Aug 18, 2011, 08:08 PM
OOPS
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USA, GA, Cochran
Joined Jun 2008
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LOL yea think its a sinus infection but the nurse said I lost 4 lbs..I told her I did that yesterday....I know TMI.servos should be here tomorrow.Maybe my horsepower will come next week.
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