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Old May 24, 2015, 01:06 PM
Aeroplayin is online now
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Quote:
Originally Posted by Enterprise7 View Post
OK

I did some ground WOT test back at the end of March. Second test after the pack bled off a little of the peak charge.

75-73A
6897-6796 RPM
46.2-45.2V

My A60-8S is a little hotter wound. 194ish. Aero has the exact number. I did a couple of other tests. The earlier one is a little better with more charge. Another one on the other set.

75-71A
6976-6801 RPM
46.7-45V

Now airborne the last set peaked at 7504 RPM. 46.2V, 50A.
First set 7300 RPM, 45.9V, 56A.


My A60-8S was 191.67 unloaded RPMs per volt and your A60-8S was 193.59. But when I make the Amps adjustment, they are both 191.67. Alan's was 186.62 after compensating, but his voltage was a discharged 3.68 per cell, and the Amps draw on an unloaded system was about twice our somewhat similar current.

Using your 46.2v and 193.59Kv, the 21x10 electric beech should do 6892 RPMs if I select the correct motor weight efficiency from the PAR Calc menu. The Calc says 70A so the results are real close. Even closer when you consider that you're running at 1.4A unloaded to start with.
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Last edited by Aeroplayin; May 24, 2015 at 01:12 PM. Reason: added the quote.
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Old May 24, 2015, 01:31 PM
Enterprise7 is online now
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Probably get even closer when you put in the 40-50 degrees it was that day.
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Old Yesterday, 12:20 AM
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Quote:
Originally Posted by Enterprise7 View Post
All of this makes me feel bad the plane my A60-8 was on is defunct for now. The motor is fine. The new planes I am assembling will get 4330s instead.
Can you tell me what kv and prop you are planning on using with the 4330? I have a 4330-216 and was thinking about putting them in this plane with 12S 3300 packs. I currently get around 3000 watts from this setup and wanted to see if other feel that is sufficient power.

Also, does anyone know why this plane requires 200oz/inch servos vs. other Extreme Flight EXP planes that require 300oz/inch servos? Thanks.
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Old Yesterday, 12:43 AM
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Hi guys,
Just finished my baby with OS GT33 but I have a small problem. Seems that with the CG at 5.5" as is written in the manual is tale heavy and I have to go like 6" and something. I have Savox 1256TG in the plane including throttle, with 2 packs of 2200 2S for receiver and 3000 for ignition. I did the CG with the tank empty is 500CC. So for those with OS GT33 how it went your CG? and for the rest with gas engines in the range of 33 CC capacity how you managed the CG? If at this point in time it is around 6" I think I should not fly it like this right? Even if I saw that most of you guys said that 5.5" as is in the manual is nose heavy.
Thx,
PS> I am looking forward to not add extra weight and try to play as mush as possible with what I have inside the plane.
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Old Yesterday, 07:25 AM
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Quote:
Originally Posted by bogdan.motrici View Post
Hi guys,
Just finished my baby with OS GT33 but I have a small problem. Seems that with the CG at 5.5" as is written in the manual is tale heavy and I have to go like 6" and something. I have Savox 1256TG in the plane including throttle, with 2 packs of 2200 2S for receiver and 3000 for ignition. I did the CG with the tank empty is 500CC. So for those with OS GT33 how it went your CG? and for the rest with gas engines in the range of 33 CC capacity how you managed the CG? If at this point in time it is around 6" I think I should not fly it like this right? Even if I saw that most of you guys said that 5.5" as is in the manual is nose heavy.
Thx,
PS> I am looking forward to not add extra weight and try to play as mush as possible with what I have inside the plane.
Your statement about being tail-heavy at 5.5" and you having to go 6"-something is a little confusing.
I think you mean that "as your plane is now" if you check it at 5.5" the tail drops, and you're finding the actual C/G past 6".
(The C/G is where the C/G is... So just making sure we're on the same page )

You're measuring straight back from where the Leading Edge touches the fuse, right? Not over the wing?
If not, mark where the leading edge begins, with the wing on, then take the wing off and measure straight back toward/across the wing tube sleeve.

If the balance is currently between 5.25" and 6.5" just go fly it, and adjust it to your tastes from there.

On my own 78" Extras, I found that I liked them balanced 1/4" or so in front of the wing tube.
This was easy to achieve by just moving batteries, using recommended equipment and several different engines
If I'm understanding you correctly, this should be the case for you as well. Especially with three batteries you can move.

Other people like the CG a little bit further back.
The plane is a sweetheart though. If you're in the general vicinity of the tube, it'll fly, and you can adjust to taste from there.
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Old Yesterday, 08:02 AM
Aeroplayin is online now
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Quote:
Originally Posted by falcon7a View Post
Can you tell me what kv and prop you are planning on using with the 4330? I have a 4330-216 and was thinking about putting them in this plane with 12S 3300 packs. I currently get around 3000 watts from this setup and wanted to see if other feel that is sufficient power.

Also, does anyone know why this plane requires 200oz/inch servos vs. other Extreme Flight EXP planes that require 300oz/inch servos? Thanks.
I'd venture to guess that most of the guys here doing any XA or 3D with their 78 are using servos with torque over 300 oz-in. Mine are 347 oz-in at 7.4v, which I'm very happy with, and I'd definitely not go less than 300.

I may buy the new XFC design scheme, which is heavier than my version-1, and if I do I'd go with more power on the motor and use the $99 SV-1270TG at 487 oz-in at 7.4v.

The DM4330-216 on 12S with a 20x8 will do 21.5 pounds of thrust at 8000 RPMs and should pull a 13 pound plane around well. On the EF Power thread we do discuss a 21 and 22 inch prop for this plane much more often. 3000W with a 21 inch prop is a little different than 3000W with a 20 inch prop because of torque. 2.42 lb-ft for the 20", 2.57 for the 21", and 2.72 for the 22". The difference seems small, but it is very noticeable in some maneuvers.... like the servo torque.
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Old Today, 03:27 AM
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Quote:
Originally Posted by C_Watkins View Post
Your statement about being tail-heavy at 5.5" and you having to go 6"-something is a little confusing.
I think you mean that "as your plane is now" if you check it at 5.5" the tail drops, and you're finding the actual C/G past 6".
(The C/G is where the C/G is... So just making sure we're on the same page )

You're measuring straight back from where the Leading Edge touches the fuse, right? Not over the wing?
If not, mark where the leading edge begins, with the wing on, then take the wing off and measure straight back toward/across the wing tube sleeve.

If the balance is currently between 5.25" and 6.5" just go fly it, and adjust it to your tastes from there.

On my own 78" Extras, I found that I liked them balanced 1/4" or so in front of the wing tube.
This was easy to achieve by just moving batteries, using recommended equipment and several different engines
If I'm understanding you correctly, this should be the case for you as well. Especially with three batteries you can move.

Other people like the CG a little bit further back.
The plane is a sweetheart though. If you're in the general vicinity of the tube, it'll fly, and you can adjust to taste from there.
Thx for your answer. Yes, sorry for stating in a different way. Indeed is like this. What I missed when doing the CG was the cowl which it seems that is 160 gr so with this should work. I did the fix last night, today will do the CG and see with this 160 gr where I stay but I think it should be fine. Yes, did the measure from the leading edge. Will get back after I check tonight.
Cheers,
Bogdan
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Old Today, 04:04 AM
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You need to put the prop and spinner on also. That makes a big difference. It has to be 100% flight ready to set your cg.
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Old Today, 04:58 AM
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Yup, will do so as prop is 78 grams. In this picture I was just finishing to mount the cowl. Initially will go without spinner as a good one it is too expensive and I'm out of money after investing in this plane. Will go latter one with a spinner as well.
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