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Old Dec 26, 2011, 04:07 AM
Gravity sucks.
Australia, QLD, Toowoomba
Joined Mar 2011
564 Posts
Quote:
Originally Posted by NitroCharged View Post
[SIZE=4]FIRE! FIRE! FIRE!

That will buff out.

I had a fairly successfull if similar story (but no fire) flying my T-45 on the friday just gone.

did a series of low passes over the strip where a mate had placed his iPhone with a doppler speed recorder on it...

the wind was blowing 30-40kph that morning so i'm not sure if that affects the readings, but he said i had an average level pass speed (WOT) of 170kph with the down wind readings being something like 200 and the upwind readings something like 160.
the final pass i took the bird nice and high for a "gravity assisted" pass which was recorded as being 247kph.

this is a lot faster than i was expecting... and using 4s 3000 40c 'black tornado' 4800 stock motor and HK 5blade 64mm fan.

However, the file my mate sent me from his iphone turned out to be a CSV file from my other plane- skyangel 50mm T-45. so i guess that makes all of the above figures hearsay.

Going out on a high note as they say, i put a 5s 3000 30c battery into the bird and took off for another set of measurements. Level takeoff, into the wing, bring it around for the low pass, go wide open throttle, and then dead over the center of the strip the motor totally cuts out and i'm flying with 0 power downwind.

still have control though, so i manage a landing in a nearby field, and go to investigate.

result: out of 9 the motor has 3 burned out coils. (the copper enamel's burnt off to a black merged mess.)

will be needing a rewind... - maybe that's the result of multiple high speed wide open passes on 4s plus one attempt at 5s WOT pass... on a 4800kv motor.

i wish i could be more specific with details but that's all i have.

next time i'll have to verify those numbers with a gps recorder.

anyone have any suggestions on motor rewinding?
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Old Dec 26, 2011, 04:30 AM
Team30 Micro EDF
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Adelaide, Australia
Joined Apr 2004
11,254 Posts
M_ark, you burnt out a phase on the motor. Simple to rewind - but the whole lot has to come off and a fresh set of winds applied.

I tested my motor today - absolutely fine. I don't have a big enough ESC so will do a ring around this evening to see if I can scrounge one off a mate to get me through.
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Old Dec 26, 2011, 06:54 PM
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Joined May 2011
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little but important

For proper balance, should I invert the plane, or do it in normal position?
In my case if I invert it tends nose heavy.
If position is normal is tail heavy!!!!...
I don't understand, it's the first time it happens on a plane!!!...
Please help me, of this depends on a successful flight

Thanks!
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Old Dec 26, 2011, 10:35 PM
Gravity sucks.
Australia, QLD, Toowoomba
Joined Mar 2011
564 Posts
Quote:
Originally Posted by NitroCharged View Post
M_ark, you burnt out a phase on the motor. Simple to rewind - but the whole lot has to come off and a fresh set of winds applied.

I tested my motor today - absolutely fine. I don't have a big enough ESC so will do a ring around this evening to see if I can scrounge one off a mate to get me through.
Nitro - do you have any suggestions for where i can find tear-down and rewinding instructions? (or could i send the motor to you?)
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Old Dec 26, 2011, 10:56 PM
Just an Earth bound misfit - I
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Canada, ON, L'Orignal
Joined Nov 2010
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Quote:
Originally Posted by Leojet View Post
For proper balance, should I invert the plane, or do it in normal position?
In my case if I invert it tends nose heavy.
If position is normal is tail heavy!!!!...
I don't understand, it's the first time it happens on a plane!!!...
Please help me, of this depends on a successful flight

Thanks!
For a low wing aircraft the most accurate method is with the plane inverted. It should be level when the CG of correct.

The opposite applies for high wing aircraft. Check CG with aircraft right way up.
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Old Dec 27, 2011, 04:56 AM
Team30 Micro EDF
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Adelaide, Australia
Joined Apr 2004
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M_ark, here's a DIY diagram. If it fries your head, I can do it for you.
.
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Old Dec 27, 2011, 10:09 AM
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United States, TX, Grand Prairie
Joined Nov 2005
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Quote:
Originally Posted by NitroCharged View Post
M_ark, here's a DIY diagram. If it fries your head, I can do it for you.
.
WOW, winding a motor is WAY easier than what I thought it would be.

How do you calculate KVs for the motor then?

Is there any high quality winding wire that will give lower internal resistance?

I like outrunners in EDF more cause it's usually harder to burn them up.

Thx in advance for any input
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Old Dec 27, 2011, 11:46 AM
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Joined May 2011
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Quote:
Originally Posted by vanderbrander View Post
For a low wing aircraft the most accurate method is with the plane inverted. It should be level when the CG of correct.

The opposite applies for high wing aircraft. Check CG with aircraft right way up.
Thanks for you answer!!!...The plane is now with the correct balance!!!
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Old Dec 27, 2011, 04:32 PM
Team30 Micro EDF
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Adelaide, Australia
Joined Apr 2004
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Here FrankenHawk ready to hit the skies again!



.
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Old Dec 27, 2011, 05:36 PM
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USA, MD, Frederick
Joined Jan 2010
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A sheet of 3mm Depron and it will probably fly as if nothing had happened!
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Old Dec 27, 2011, 10:12 PM
Team30 Micro EDF
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Adelaide, Australia
Joined Apr 2004
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Good thinking Fred!

I won't be doing it though.... already getting the cart going for a new kit.
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Old Dec 27, 2011, 10:47 PM
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Cottonwood Arizona
Joined Aug 2003
600 Posts
Anyone successfully adapt this plane to a 70mm? Looks like it could be done if you can access the fan bed - seems splitting the fuse in half would be the easiest solution?
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Old Dec 27, 2011, 10:50 PM
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USA, MD, Frederick
Joined Jan 2010
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@topher39: Yes, it has been done.

http://www.rcgroups.com/forums/showthread.php?t=886736

Hobbyking T45 Hawks Grass Take Off (0 min 35 sec)

HK T45 Bae Hawk(EPO)70mm Maiden Day - Fun flight Laya-Laya (0 min 55 sec)

HK T45 Bae Hawk 70mm (2 min 18 sec)


I think because of the airframe drag, the increase in speed is not what you'd expect stepping up from 64mm.
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Old Dec 27, 2011, 11:00 PM
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Cottonwood Arizona
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Thanks for the info on 70mm!
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Old Dec 28, 2011, 04:47 AM
I don't want to land yet!
Joined Jan 2010
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The one taking the onboard video in this clip is a 70mm wemo 5 blade and 2w20 motor...
it has the duct modification also... needed to remove a small amount of foam to fit it...

Name: T45-Duct-Mod.jpg
Views: 136
Size: 73.7 KB
Description:

http://youtu.be/aLPbakdR5W8?hd=1


Also note that this was taken at nowhere near full throttle... the one in front is Nitro's 64mm stock motor.

I actually cut the bottom out of the fuselage at the rear to remove the foam with a round sanding block, then I had room to get the thrust tube setup in it easily.... then just glued the piece back in after.

Another option is an ExtremeRC 64mm alloy fan/motor combo, Jim350 was running it in his and it went very well also.

Cheers,
Dave
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Last edited by Strike3; Dec 28, 2011 at 05:00 AM.
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