Help with Ben Buckle Novice

[MattS]

Hi

 

I have just started building a Ben Buckle Novice and have run into a problem building the bottom of the wing.

 

I have cut, pinned out and glued the leading edge planking, the centre planking and the trailing edge. The next step on the instructions is to cut and fit the capping strips. Nothing in the wood kit or on the plan is shouting capping strip at me though.

 

I would appreciate a quick explanation of what the capping strips are and where I might find them on the plan.

 

Thanks

Matt

 

[Alan Cantwell]

capping strips are simply balsa stribs, that have multiple uses, they increase the width of a wing rib, to save the covering sagging, and they give the rib a girder setion, to increae rigidity, they are, on the model size you have, about 6mm wide, and 1.5mm thick, grain runs root wise, as against span wise, select medium balsa, as hard balsa will be hard to bend to the airfoil shape, they can be found on the rib top, from the mainspar, back to the trailing edge, and they go top and bottom of the rib

Edited By Alan C on 28/03/2011 21:42:24

[flytilbroke]

On the plan it says 1/16th by 1/4 inch. you will find strips in the wood pack. Carefully cut EACH strip acurately, they are fitted "T" shape on the ribs.

 

Enjoy

 

Edited By flytilbroke on 29/03/2011 00:03:35

[David Ashby - Moderator]

Matt, in this photo you can make out the capping strips laying on top of the ribs. You could always cut them from larger sheet balsa if balsa of the required size doesn't seem to be there.

 

[MattS]

Brilliant. Thanks for the help everyone. I think I know what I am doing now.

 

Before I go ahead and start cutting and glueing I would like to confirm some terms that have confused me. 'Root wise,' is that LE to TE and 'Span wise,' root to tip?

 

Thanks in advance

 

[Pete B]

Yep, you've got it!

 

Pete

[MattS]

The capping strips are glued down. LE glued down.

 

Now I seem to have a small issue with the wing ribs. They appear to be cut about 1/16 to long where they meet the LE.

 

So what to do about. I guess my options are;

1. Trim the ribs.

2. Slot the LE.

3. Move the lower spar toward the TE a bit.

 

I am favoring option 2 but worried I will be setting myself up for problems later if I don't rectify in the right way.

 

Opinions anyone?

[Richard Wood]

Matt,

I'd go for number 1 & make the cut out in the ribs the same width

as the LE.

Slotting the LE might be a tad awkward as it's already glued down,

and moving the lower spar back would leave it offset from the sheeting

a little bit.

 

[MattS]

Thanks Richard. Have trimmed the ribs as per your suggestion.

 

The next item on my list is an aileron conversion. I think I have my head around most of what's needed except how big to make the control surfaces.  No doubt I will be back with more some more questions once I have the measurements together.

 

Thanks for your patience. The help I am getting is proving really useful

 

Edited By MattS on 02/04/2011 23:42:55

[MattS]

I have made a quick sketch of my aileron conversion plan. Hopefully it is self explanatory, although there may be a typo on the TE dimensions. Damn technology doesn't work well with fractions...and neither do I for that matter

 

The orange line in front the trailing edge represents additional webbing not in the original plan.

I have not quite worked out all the details, but would appreciate some opinions. How sensible is it looking ?

 

All comments, good and bad, gratefully received.

 

Edited By MattS on 04/04/2011 21:58:30

Edited By MattS on 04/04/2011 22:02:13

[flytilbroke]

I suggest that you design some holes into the tail panels as it is likely to come out a bit tail heavy. I had observed other guys had done this, yet decided to build as per the plan. Mine certainly would be tail heavy without some lead up front. After I have given it a few trial flights I think I will strip the tail covering and sort that problem out.

[Pete B]

Posted by MattS on 04/04/2011 21:58:06:

I have made a quick sketch of my aileron conversion plan. Hopefully it is self explanatory, although there may be a typo on the TE dimensions. Damn technology doesn't work well with fractions...and neither do I for that matter

 

The orange line in front the trailing edge represents additional webbing not in the original plan.

I have not quite worked out all the details, but would appreciate some opinions. How sensible is it looking ?

 

All comments, good and bad, gratefully received.

 

Edited By MattS on 04/04/2011 21:58:30

Edited By MattS on 04/04/2011 22:02:13

 

Eyeballing, it looks about right, dimension-wise. You mention webbing on the orange line. I would cut the ribs along that line and insert a spar, say 1/8 x the thickness of the wing at that point, notched into R4 (ie the fourth rib from centre), to the outermost rib. You can either notch the spar to receive the ribs, the less strong alternative being a butt joint. You can use the offcuts to form an aileron profile or just fashion the ailerons from t/e strip.

 

Ben Buckle kits are notoriously inaccurate from what I've read - someone else here mentioned rib sizes a while back.

 

If you are fitting ailerons, you may find it beneficial to reduce the wing dihedral to give you a bit more aileron authority.

 

Hope this helps,

Pete

Edited By Pete B on 04/04/2011 22:36:00

[MattS]

Thanks Pete B and Flytilbroke. That's given me some ideas to play with and things to consider.

 

Will report back with progress when I make some.

 

 

 

[Jimbo565]

Matts,

Speaking from experience with my Mini Super I would increase the width of the aileron,at present you have it same size as the T/E,Iwould be tempted to double the width.

This is the mod i did to my Mini Super,note the T/E width ailerons,they have just about enough authority to turn the model and the model will roll but it takes all day to do it.

The ailerons should be the same width as the flaps to improve the authority ,I built a small bipe and made the same mistake of making the ailerons same size as the T/E with same result,eventually had to make wider ailerons to get the model to perform.

 

Something to consider.

 

Jim