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Old Jun 13, 2008, 06:22 PM
Houng-wen Lin
GWS4CEO's Avatar
Shijr, Taiwan. DungGwan, China. City of Industry, California.
Joined Sep 2001
19,445 Posts
If you keep GWS A4 with GWS EDF75, should be fly with great performance as our result.

However, I saw some flyers change to be with 70mm, or even 6xmm. That may be caused the thrust line changed?

We did not intend to let GWS A4 to be with other power units.
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Old Jun 13, 2008, 06:31 PM
Foam Flingin' Nitro Pilot
San Diego
Joined Mar 2008
360 Posts
Quote:
Originally Posted by GWS4CEO
If you keep GWS A4 with GWS EDF75, should be fly with great performance as our result.

However, I saw some flyers change to be with 70mm, or even 6xmm. That may be caused the thrust line changed?

We did not intend to let GWS A4 to be with other power units.

I was using a 75mm.... not GWS, due to fan issues.
Therefore, the thrust line has not changed.
It is obviously the duct that is causing the problem.

The bottom of the duct curves upward in the last few inches.
Wouldn't you expect that this would cause the thrust to be vectored upward as it leaves the duct?
I would...

I guess this won't be paid any closer attention in the new models.... great

Maybe we'll get lucky, and the shape of the fuselage won't lead them to make this mistake again...
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Old Jun 14, 2008, 05:22 AM
Unrepentant Carnivore
jamesdr's Avatar
Brandon, Fl
Joined Mar 2005
2,499 Posts
Regarding the "thrust vectoring" I suppose a test would be to see if once your A4 is trimmed out at WOT and then shut down the fan, the nose would drop. Mine doesn't.

Jim
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Old Jun 14, 2008, 11:13 AM
I'm just here to fly
f86esabre's Avatar
Sarasota,Florida
Joined Jun 2007
991 Posts
Pancake1
I am respectful when I say this.I think that most of the guys here have not had that problem with the duct. I know I have'nt seen this problem on my plane.I flew mine with the stock set up and then changed the motor and added the thrust tube.The AOA has more of an effect on take off,but that's landing gear geometry.
Steve
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Old Jun 14, 2008, 11:34 AM
I'm just here to fly
f86esabre's Avatar
Sarasota,Florida
Joined Jun 2007
991 Posts
Now back to the F-4. I heard it from a little bird that it's time to let Mr. Lin know what version of the F-4 you guys want.I would love to see a nose for the F-4B/C/D/J/S and a nose for the F-4E but that will probably not happen. So my vote is for the F-4B/C/D/J/S with the standard radar nose. That way a lot more schemes could be done. Time to add your comments.
Steve
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Old Jun 14, 2008, 01:03 PM
Unrepentant Carnivore
jamesdr's Avatar
Brandon, Fl
Joined Mar 2005
2,499 Posts
Choices

My favorite is the "G" model but truth be known, ANY F-4 would be welcome in my stable.

Credit these from Air Vectors <http://www.vectorsite.net/avf4.html>

A longer nose would allow for those who wish to bash back to a B/C/D/J/S nose or go the RF-4 route.

Love the Rino!

Jim
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Old Jun 16, 2008, 08:17 AM
Planes, need more planes
flyguide7's Avatar
United States, MO, Chesterfield
Joined Feb 2006
850 Posts
The G model looks great and has been my favorite. Count one vote for the G model.
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Old Jun 16, 2008, 10:04 AM
Foam Flingin' Nitro Pilot
San Diego
Joined Mar 2008
360 Posts
Quote:
Originally Posted by f86esabre
Pancake1
I am respectful when I say this.I think that most of the guys here have not had that problem with the duct. I know I have'nt seen this problem on my plane.I flew mine with the stock set up and then changed the motor and added the thrust tube.The AOA has more of an effect on take off,but that's landing gear geometry.
Steve

Well, I tested mine pretty thoroughly, and it had a problem.
The thrust tube fixed it.

CorsairNut obviously had the same problem, as seen in his video.... but I would've thought that he had a thrust tube.... not sure.

At full throttle it would push the tail down, and cause it to fly at higher AOA, which then limited speed. It was very obvious.
This could be compensated for with nose weight and/or nose down trim.
As an example, CorsairNut didn't think he had a problem either... until he crashed his plane (don't know if it was stock duct)... so people flying with the stock duct could have this problem, and have covered it up by adding weight and trim...

Also, this is different than the landing gear thing... although one can compound the other.
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Old Jun 16, 2008, 08:52 PM
I'm just here to fly
f86esabre's Avatar
Sarasota,Florida
Joined Jun 2007
991 Posts
CNs' plane crashed because he added power when he was low,slow and had everything hanging out.He just got behind the power curve. No doubt if your CG is farther back then pitch changes will be quick and possibly end in a crash because of a high application of power.
Steve
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Old Jun 16, 2008, 09:57 PM
Pusher jets rule!
crxmanpat's Avatar
Mesa, AZ
Joined Jan 2006
17,118 Posts
Steve,

I was going to say that, but glad you beat me to the punch!

Here's the vid of CN's A-4 crash for those who have not seen it.

http://www.rcgroups.com/forums/showthread.php?t=808084

Pat
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Old Jun 17, 2008, 01:01 AM
Registered User
kahloq's Avatar
Fort Collins, Colorado, USA
Joined Dec 2005
7,821 Posts
Looks to be a good F4. Im not impressed with the Kyosho offering. For me, the GWS will have to be modded to a twin setup. Hmmm XF 56mm fans with Wicked Extreme motors on 4s sounds about right to me ...or twin Alfa 60/25's with LSJS's. Heck, even regular EDF55's with GWS Green 3900's on 4s would be good too.
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Old Jun 17, 2008, 10:59 AM
Der Flieger kommt schnell
WWIFlyin'Ace's Avatar
Staten Island
Joined Jun 2005
383 Posts
A,B,C,D,E.......model,
Heck it is starting to sound like the USS Enterprise!

Mr. Lin,
Just make any one!

and be quick about it
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Old Jun 17, 2008, 11:04 AM
Pusher jets rule!
crxmanpat's Avatar
Mesa, AZ
Joined Jan 2006
17,118 Posts
Quote:
Originally Posted by WWIFlyin'Ace
A,B,C,D,E.......model,
Heck it is starting to sound like the USS Enterprise!

Mr. Lin,
Just make any one!

and be quick about it
Here here!

Pat
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Old Jun 17, 2008, 12:31 PM
Foam Flingin' Nitro Pilot
San Diego
Joined Mar 2008
360 Posts
Quote:
Originally Posted by f86esabre
CNs' plane crashed because he added power when he was low,slow and had everything hanging out.He just got behind the power curve. No doubt if your CG is farther back then pitch changes will be quick and possibly end in a crash because of a high application of power.
Steve
So, I've tested and verified a thrust vector problem... and even CorsairNut seemed to agree that his was the same issue... but you think his plane crashed due to... what?

You think that going to full power with a tail-heavy airplane is going to slide the tail uner like that? A tail-heavy airplane will sink the tail gradually as the plane slows... not when you add power, or increase speed. Period.

The only thing, IMO, that can change the attitude of an aircraft that abruptly, under those conditions, is a thrust issue.
If you have a different explanation, please explain...
Peronally, I don't think your brief theory above is correct.

Respectfully....
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Old Jun 17, 2008, 12:40 PM
Unrepentant Carnivore
jamesdr's Avatar
Brandon, Fl
Joined Mar 2005
2,499 Posts
Sorry - it looks like a power on stall to me. High AOA, no air speed, flat spin into terra firma. Done it / seen it before.

Jim
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