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Old Dec 14, 2002, 02:06 AM
Registered User
Madison, WI
Joined Jan 2002
146 Posts
More CG Calculators

Here's a nifty program that calculates the CG of wings with multiple tapers (the F4 sort of is)
http://www.jean-claude.etiemble.com/...loads/cmEi.zip

And here's a slightly different version of the CG diagram above

DM

p.s. trying REALLY hard not to buy one of these great looking kits. I have way too many unfinished projects as it is, but I'll probably get one anyway.....
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Old Dec 14, 2002, 02:12 AM
HobbyKing
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Hong Kong, Hong Kong Island, Hong Kong
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Awesome, I love the Yellow with the Transparent blue, ultra cool.

--Paul
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Old Dec 14, 2002, 06:46 PM
Forgot how to fly
Mike Parsons's Avatar
Atlanta, Georgia
Joined Oct 2002
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Tail

Ok, Have another question. The Ducts are in place, (great idea using the Laser transparency!) and she is all framed up. That is with the exception of one thing. And that is installing the 11/16th stringers that the Elevon Servo's hang on. THere are two groves in F7 but can tell where to attach it to F8 and F6? Anyone have any pics that can shed some light on this? After I get those four stringers on, I can cover it. Altough I am still deciding where to put the hatch. THe directions state to hang the battery pack on top....where are you putting yours? For the battery to be on top There would need to be two hatches, one on the bottom and one on top. I don't think there is enough room on the bottom to place a battery pack below the duct work? Am I wrong?

Thanks in advance.
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Old Dec 14, 2002, 07:04 PM
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Los Angeles
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Take a look at Hector's pic of his tail section on page 11 of this thread. If you need a better pic I can try to dig something up in my files although I am pretty sure they are all posted in the Online Manual page listed in the construction manual. As for the hatch I would almost be willing to say make it from F1 back to just behind the fans. This would give you plenty of room to adjust CG for the battery pack.

John
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Old Dec 14, 2002, 07:41 PM
Forgot how to fly
Mike Parsons's Avatar
Atlanta, Georgia
Joined Oct 2002
10,177 Posts
Servo stringers

If you can dig something up, that would be great. I had already taken Hector's picture of the tailcone and blew it up to see if I could determine exactly where it connected on F-8 and F6 but no luck. You might want to have some indentions laser cut into future kits. There is too much left to the imagination with the installation of this plane. That is for the balsa challenged individual like me

Mike
FF
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Old Dec 16, 2002, 01:47 PM
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Los Angeles
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Mike -

I can't seem to find any pictures other than the ones in the gallery already up. What exactly is the issue and maybe myself and some of the other builders here can talk you through it.

---------------------

Ok we have placed an important update up on the webpage listed in the construction manual. Please stop by there and check it out. If you have any questions and/or comments please don't hesitate to e-mail us!


John
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Old Dec 16, 2002, 02:18 PM
aka ben wilson
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louisville, ky, usa
Joined Mar 2001
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just got my kit!

the packaging on the F4 is excellent, and my cursory examination of the laser-cut parts has shown that they are in great shape, and well-done (thanks to AERC / Officeshops!)

one question to pilatus: what kind of covering did you use on your blue and yellow model?
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Old Dec 16, 2002, 10:45 PM
Forgot how to fly
Mike Parsons's Avatar
Atlanta, Georgia
Joined Oct 2002
10,177 Posts
battery hatch.

Ok. I think I have the Elevon Servos mounting stingers worked out. It is quite a bit of trial and error and matching up and test fitting to get the right angle, etc, etc, etc. With that out of the way and the only thing left is the Battery Hatch I started scrtching my head and eureka! I actually cant take credit for it as Glenn gave me the idea in the way he has the LJ50's battery hatch laid out. It works very good and is less weight than if I sheeted the bottom for the hatch as I used premium competition balsa. This is where the plans call for the battery to be and I assume it is where the battery sat during the beta tests (am I right John?). There is just not enough room that I can see on the bottom of this between the stringers and the fan ducts to mount a battery. I still have to core a few holes in the floor of the battery hatch that will lighten it still, plus add some ventilation. If I over-engineered, please tell me (Glenn?). I Think it works well and will be next to impossible to see once it is covered. Oh, I have decided to cover it military gray with all the trimmings. The canopy will be temp as after the maiden flight, I will foam carve a pilot for more detail.
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Old Dec 16, 2002, 10:46 PM
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another view

another
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Old Dec 16, 2002, 10:46 PM
Forgot how to fly
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Atlanta, Georgia
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Last one

Last one
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Old Dec 17, 2002, 01:13 AM
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Los Angeles
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Looks great. The beta test had all equipment located where the plans show and ran fine, however I have had a few e-mails in regards to the CG being about 3" forward of where the plans show. I would reccomend anyone flying the F-4, or any EDF for that matter, for the first time to get low to the ground and make a hand launch roughly 2-3 feet off the ground. This gives you room for error. 3 feet is alot safer than 6-8! Again this is all dependant on your setup and the AUW but it seems most are finding the CG to be a little forward of the prototype.


John
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Old Dec 19, 2002, 01:04 PM
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raleigh, NC usa
Joined Aug 2001
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pics

Hey folks,

the guy on the pervious page that has the calculation for the cg is - in my opinion right on the money.

I test flew the f4 this weekend and found it to have a boat laod of thrust but a cg issue that requires the cg to be moved foreward by about 3 to 3.5" of the location on the plans.

I am going to make the mod by moving the battery in front of f3 and by adding modelling clay to the nose to make any further movement.

The plane is very roll sensitive to the tailerons but much less sensetive to the pitch control.

I used (two numbers represent the low and high rate setings on my radio) 1/4"- 3/8 up and down for roll and 3/8 - 1/2 up and down for the pitch. this seemed to work, any more than 1/2 and you will stall the tailplane.

For those that were thinking about LI cells, you are drawing way to much current to safely use them, go with the aaa 7 cell packs velcroed to the former.

I added panel lines with an ultra fine Sharpie . . looks Choice even with the black bunny scheme!

I plan on doing my repair work this weekend with flying on sunday or monday depending on the weather.

Phil
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Old Dec 19, 2002, 01:09 PM
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pics

pics
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Old Dec 19, 2002, 01:20 PM
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pics
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Old Dec 19, 2002, 01:54 PM
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Kevin P's Avatar
Cicero, Indiana
Joined Oct 2002
266 Posts
Quote:
For those that were thinking about LI cells, you are drawing way to much current to safely use them, go with the aaa 7 cell packs velcroed to the former.
Phil, what were you drawing on the two fans? I was thinking of Li-Poly's with fans but had yet to test it.
Thanks,

Kevin
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