Lightening wing ribs

[Tim Tim]

Hello,

I saw some pictures on a web site that showed some wings before being covered. I could see that there were holes made in each of the ribs, larger towards the centre of the rib, smaller going outwards to the leading edge and the trailing edge. I think in real life this is done, is it not,? Not least as they have to run cables and whatnot through the wings?

Is this something you would find in a kit? Or would you do this yourself? I suppose the idea if to lighten the structure. Is the idea to shave as much balsa away as possible, leaving a firm enough model that will fly? If so, would you go further in some ways? What other methods can be used to lighten the airframe?

Also, does this affect the CofG?

Thanks,

Tim

 

[wonwinglo]

*** Hello Tim,a good question,most small kit design models can benefit from some form of shaving weight and many attack the wing ribs as a suitable candidate ! whilst lightening ribs by cutting numerous holes in them could save a little weight this has to be done with care,what you have to weigh up is-does the removal of balsa add more problems with regards the structural strength ? it is doubtful whether there will be much benefit on a model of some 12-18 inches wingspan,it would be better to reduce the thickness of the said ribs by either sanding or reducing the thickness of timber,the usual method is to remove balsa with either a leather punch ( obtainable from that modellers friend Proops brothers ) or to use one of those sharpened sets of punches where a small hammer is used whilst the ribs are placed onto a piece of copper.

If you weigh the removed 'holes' you will be surprised how little weight it has removed,but if you weigh the sanded dust you will be more imressed,dont ask me why ?.

This is an area where fanatical lightening in the interests of weight saving can lead to a lack of structural integrity and too frail a structure if you are not careful,so tread with care,is lightening ribs with holes to this scale worth it ? doubtful in my humble opinion.

I doubt whether you will notice any remarkable changes in the centre of gravity either,as always err on the slightly forward c of g keeping the tail light as possible.

Trust this answers your question adequately.

 

[Tim Tim]

Read with interest, Barry.

Tim

 

[Phoenix]

well in real planes the fuel tanks are in the wings but i think there would be a space for the flaps and airielon cables and such