RE: Extra 300 Prototype #2  
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All Forums >> RC Airplanes >> Giant Scale Aircraft - 3D & Aerobatic >> Carden Aircraft >> RE: Extra 300 Prototype #2
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RE: Extra 300 Prototype #2 - 12/24/2006 1:10:56 PM   
RickP



Posts: 1679
Joined: 1/1/2002
From: Levittown, NY, USA
Status: offline 		I know you've been working on this, whats the latest?
RP

(in reply to RobT)
       Post #: 51

RE: Extra 300 Prototype #2 - 12/25/2006 1:04:43 PM   
RobT



Posts: 674
Joined: 9/29/2003
From: Whitestone, NY, USA
Status: offline 		I thought I took photo's last week...but can't seem to find them. Set the stab incidence...

With the wings set at zero...Screw down the L brackets onto the stabs. Slide the stabs onto the tube and up against the fuse. Angle Finder onto the first stab. Position the first stab to zero degrees and lock it into place by gluing some scrap blocks to the side of the fuse.

When this is locked into position trace the outline of the L bracket with an exacto. Slide the stab away and relive the 1/8 balsa fuse sides at the location of the L bracket.

After the side is relieved The stab can be replaced to the same position due to the balsa blocks. check to make sure the stab is still at 0 degrees. Drill through the L bracket and into the 1/4" ply for the 6-32 screw, again remove stab and open the fuse hole to accept a T-nut. last check to make sure the stab is still at zero. Repeat for other side.

(in reply to RickP)
       Post #: 52

RE: Extra 300 Prototype #2 - 12/25/2006 1:12:30 PM   
RobT



Posts: 674
Joined: 9/29/2003
From: Whitestone, NY, USA
Status: offline 		Due to internet rumors, I decided to back up the L Bracket with some 1/4" dowel. So after both stab incidences were set one was removed and a hole was drilled through both fuse sides parallel to the stab tube at location of the 1/4" ply and the stab. By using the 1/4 ply which is already in the fuse I didn't have to add any extra wood.

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< Message edited by RobT -- 12/25/2006 2:59:56 PM >

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RE: Extra 300 Prototype #2 - 12/25/2006 3:04:25 PM   
wgeffon



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Joined: 12/2/2001
From: Bloomington, IL, USA
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quote:

ORIGINAL: RobT

Due to internet rumors,


Rob,

No rumors. I personally saw three broken L brackets last year.
2 planes wiped out. One was fixable.

Your Anti rotation pin will help.



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Wayne

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       Post #: 54

RE: Extra 300 Prototype #2 - 12/25/2006 3:04:44 PM   
RobT



Posts: 674
Joined: 9/29/2003
From: Whitestone, NY, USA
Status: offline 		Installing the retainer screw hard points...

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       Post #: 55

RE: Extra 300 Prototype #2 - 12/25/2006 3:11:07 PM   
RobT



Posts: 674
Joined: 9/29/2003
From: Whitestone, NY, USA
Status: offline 		Wayne,

Thanks for the heads up. I have seen many Carden's have long lives without any mods. I wonder what caused the failures...Is it possible the L Brackets in question were experiencing additional twisting / flexing forces due to something in their particular setups?

None the less that is why I took the insurance and piece of mind by adding the dowel. And by using the hard point that was already in the fuse their was minimal weight gain.

(in reply to RobT)
       Post #: 56

RE: Extra 300 Prototype #2 - 12/25/2006 7:02:26 PM   
paf


 

Posts: 79
Joined: 11/20/2002
From: New York, NY, USA
Status: offline 		I had one bracket start cracking on my Cap years ago. It was due to slight mis-alignment of the surfaces. The bolts were slightly stretching the plastic. It also seems that the stab tube always has a little play in it and the stabs can move up/down slightly. This movement gets transfered to the L bracket as well, so over time, it could weaken it enough to fail.

Wayne - the first hand failures you know about - did the owners inspect the brackets regularly, or did they leave their stabs on all the time and maybe overlooked a developing crack ?

P.

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       Post #: 57

RE: Extra 300 Prototype #2 - 12/25/2006 8:10:18 PM   
wgeffon



Posts: 6375
Joined: 12/2/2001
From: Bloomington, IL, USA
Status: offline 		Paul,

Two were on planes that had the stabs removed all the time.
Both of those planes had one season on them.

The other plane I am not sure if the stabs came off or not.
I am pretty sure they did as he doesnt have a trailer.


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Wayne

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       Post #: 58

RE: Extra 300 Prototype #2 - 12/25/2006 10:49:47 PM   
Flyin Woodbutcher


 

Posts: 836
Joined: 12/16/2002
From: Ashland, VA, USA
Status: offline 		Hey fellas for a little more insurance. Install a dowel in the ends of the stab tube. Drill and tap this for a longer retetion bolt. I have a 8/32 bolt in my 35 cent Cap. When the bolt is tightened down the stab can not move away from the fus. Even if the plastic bracket breaks the extra antirotation dowel will stay connected.

FWB

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       Post #: 59

RE: Extra 300 Prototype #2 - 12/25/2006 11:21:39 PM   
jmiracle


 

Posts: 592
Joined: 5/13/2002
From: Findlay, OH, USA
Status: offline 		I think an extra dowel in the stabs is all that's really needed to solve any questions over whether the plastic L brackets will hold up. Aeroworks setup their older kits with a AR pin and a bolt through the ends of the tube only and those seemed to hold up fine...I've seen several with many many seasons on them with no problems.

We trust the wings to a simple AR pin and a couple small bolts to hold them to the fuse...no reason it won't work just as well on the stabs.

With a bolt in the tubes, a dowel in the root, and root tabs or L-bracket....there are no structural worries if built correctly.

(in reply to Flyin Woodbutcher)
       Post #: 60

RE: Extra 300 Prototype #2 - 12/25/2006 11:23:07 PM   
wgeffon



Posts: 6375
Joined: 12/2/2001
From: Bloomington, IL, USA
Status: offline 		I am not trying to dispute any theory put on here but, one of the planes I witnessed had a dowell in the stab tube and also had an anti-rotation pin in the stab root.
Once the L bracket broke the LE of the stab rotated up 90 degrees ripping out the anti rotation pin and the bolt in the stab tube.

This is what we came up with on my Carden's to do away with the L brackett alltogether.





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Wayne

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RE: Extra 300 Prototype #2 - 12/25/2006 11:25:27 PM   
wgeffon



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From: Bloomington, IL, USA
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quote:

ORIGINAL: jmiracle

there are no structural worries if built correctly.


These planes I witnessed were all built by preffered Carden Builders.
(It can happen)


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Wayne

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RE: Extra 300 Prototype #2 - 12/25/2006 11:25:58 PM   
Flyin Woodbutcher


 

Posts: 836
Joined: 12/16/2002
From: Ashland, VA, USA
Status: offline 		hows that a lot better ? The ply is only glued to foam. Have seen ARFs come loose here.

FWB

(in reply to wgeffon)
       Post #: 63

RE: Extra 300 Prototype #2 - 12/25/2006 11:30:15 PM   
wgeffon



Posts: 6375
Joined: 12/2/2001
From: Bloomington, IL, USA
Status: offline 		The ply is glued to the foam root and is also encapsulated by the sheeting locking it in.
The anti rotation pin and the stab phenolic also lock the root rib in place.
The anti-rotation pin sticks into the foam at least an inch.

Like I said, I am not trying to dispute any theory or solution posted here. I am just stating what I have personally seen and what we did to eliminate the risk.

Watching three beautiful Cardens go in last year was enough to make me want something different.


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Wayne

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RE: Extra 300 Prototype #2 - 12/25/2006 11:35:29 PM   
Flyin Woodbutcher


 

Posts: 836
Joined: 12/16/2002
From: Ashland, VA, USA
Status: offline 		just a ? , no dispute. Stabs staying on is the main objective.

FWB

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RE: Extra 300 Prototype #2 - 12/26/2006 12:52:35 AM