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-   -   How will this error affect flying? (https://www.rcuniverse.com/forum/kit-building-121/11614396-how-will-error-affect-flying.html)

Scratchie 03-09-2015 06:08 PM

How will this error affect flying?
 
2 Attachment(s)
Right before glueing the fin I put two drops of CA on the fuse sheeting. I didn’t think to re-measure, and the CA threw off the fin alignment. By the time I figured out what went wrong it was too late to take the fin off and redo. Anyway, the first pic shows the fin alignment to the stab, it may not look like it but’s balls on. The second pic shows how the fin alignment is off. When I take the fuse off the board I’ll evaluate fixing it, but I really don’t think it will impact the flying of the plane (TF Spitfire).

52larry52 03-09-2015 06:38 PM

It doesn't look like your comparing the same thing in photo #2 as in photo #1. Photo #2 shows the vertical stab to be a little off square in relation to the building surface in a fore and aft direction. Having the vertical stab square to the horizontal stab when viewed from the front of the aircraft is the important thing. What you have will only change the side profile of the aircraft by the 1/6 th or so that it is off. No one will know and the plane won't care either( it will fly fine).

Scratchie 03-09-2015 06:41 PM

That's correct, it's the fore/aft alignment that's off, it's totally square with the stab.

TomCrump 03-10-2015 01:49 AM

" I didn’t think to re-measure, and the CA threw off the fin alignment."

I don't understand how CA could do this.




sensei 03-10-2015 03:34 AM

I have noticed when tacking with CA and using hot shot that it contracts as it cures, so if you use it on one side only like lets say the L/H side of a flat sided vertical and not pay attention it will certainly lean favoring the side glued with CA first'

Bob

TomCrump 03-10-2015 03:40 AM

1 Attachment(s)

Originally Posted by sensei (Post 11999439)
I have noticed when tacking with CA and using hot shot that it contracts as it cures, so if you use it on one side only like lets say the L/H side of a flat sided vertical and not pay attention it will certainly lean favoring the side glued with CA first'

Bob

If you apply CA to the other side, will it pull it back ?

I've never noticed this phenomenon. I just re-installed a fin yesterday, I better check it.

Rafael23cc 03-10-2015 06:35 AM

All of you asking how the CA threw the measurement out of alignment, you need to read the entire initial post again. The alignment was NOT thrown off while gluing the vertical stab.

Scratchie: as indicated above, if the vertical and horizontal are in fact at 90 degrees, and the only error is that much forward, I would not worry about it.

Rafael

52larry52 03-10-2015 07:41 AM

Scratchie, Keep building and don't worry about the small amount that the top of the vert. stab is leaning forward. It's such a small amount that it can't be seen nor will it change the flight of this bird. Make sure the rudder fits up nice to it so it looks right. IMHO, if this is the biggest "error" you have in the build, you did alright.

Scratchie 03-10-2015 07:53 AM

The fin-stab alignment is perfect, it’s the fore and aft that’s off. The kit instructions said do not glue the fuse sheeting at the aft end so I didn't, I just sanded everything smooth and even. But I didn’t want the epoxy from attaching the fin to interfere with the fuse sheeting, so I used two drops of thin CA and tacked the fuse sheeting in place. Well, with the fuse sheeting tacked down I should have re-sanded and re-measured. But I was focused on the fin and it didn’t occur to me. It was the slight change in positon of the fuse sheeting that threw off the fore/aft alignment. So like almost all RC airplane issues, it was pilot error, not the kit or CA. I’ll post an abbreviated build in a couple months when the plane is done, just pointing out the highlights and lowlights. .

TLH101 03-10-2015 08:20 AM

Add a piece of sheeting to the back side and taper it from top to bottom to get a vertical surface.

Scratchie 03-10-2015 08:25 AM

When the fuse comes off the building board I'll take a look. The rudder would need just a little wood/reshaping as well.

Scratchie 03-10-2015 08:26 AM

When the fuse comes off the building board I'll take a look. The rudder would need just a little wood/reshaping as well.

RCFlyerDan 03-10-2015 11:35 AM


Originally Posted by 52larry52 (Post 11999578)
Scratchie, Keep building and don't worry about the small amount that the top of the vert. stab is leaning forward. It's such a small amount that it can't be seen nor will it change the flight of this bird. Make sure the rudder fits up nice to it so it looks right. IMHO, if this is the biggest "error" you have in the build, you did alright.

+1

Granpooba 03-10-2015 11:42 AM


Originally Posted by 52larry52 (Post 11999578)
Scratchie, Keep building and don't worry about the small amount that the top of the vert. stab is leaning forward. It's such a small amount that it can't be seen nor will it change the flight of this bird. Make sure the rudder fits up nice to it so it looks right. IMHO, if this is the biggest "error" you have in the build, you did alright.

I concur !! :rolleyes: Vertical stab showing a little lean forward I am quite sure that it will not affect the performance or control of your model. If it really bothers you, you could add some balsa sheeting to the back the stab and sand or carve to correct for the lean.

One other solution, even though it may sound like it is a little distract, would be to get some CA DEBONDER and debond the vertical stab. Then just rebuild it to your liking and specs.

Personally, I would leave it alone. Folks, including myself have made much bigger mistakes and their models turned out just fine. :) That is, until they hit the ground ! :rolleyes:
Just kidding of course !! :)

757jonp 03-11-2015 05:36 AM

Heck, it might fly better! Myself, I wouldn't worry about it at all.

Granpooba 03-11-2015 06:44 AM

Thought that I would add an extra note. In real life if my memory serves me correctly, look at a Mooney Exec 21, the vertical stab is angled forward. The Mooney Exec's are fast and great flying airplanes. :)


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