Tip Weight

[Ken Culbertson]

I have always tried to use the building process to minimize the extra tip weight I need.  I don't hollow the outboard tips, cutout holes in the outboard ribs and use the heavier sheets (if I can't get great wood) outboard.  This gives me a naturally heavier outboard wing.  My question is whether or not this is a good practice.  In the pictures of uncovered wings I see here I don't see anybody else doing this which leads me to think it is not.

I have a new wing on the jig and it is not too late to do it different.

Ken

[Jim Hoffman]

Ken,

For a sport flyer, your approach is fine and is a time saver.

For a high end competition stunter, it is better to build a light wing and concentrate the tip weight in the outer most point to result in less overall weight.  Further to this end, it is obviously preferred to reduce the weight of the inboard tip and the line sweep adjustment.  Many of us work very hard to keep the IB tip and the line sweep adjustment ultra-light.  This results in a double weight savings.

In a profile e-powered model, pay attention to the battery location and weight.

[Ken Culbertson]

Ken,

For a sport flyer, your approach is fine and is a time saver.

For a high end competition stunter, it is better to build a light wing and concentrate the tip weight in the outer most point to result in less overall weight.  Further to this end, it is obviously preferred to reduce the weight of the inboard tip and the line sweep adjustment.  Many of us work very hard to keep the IB tip and the line sweep adjustment ultra-light.  This results in a double weight savings.

In a profile e-powered model, pay attention to the battery location and weight.

Would not hollowing the outboard tip be included in your assessment?  My gut tells me you are right and I am  definitely  building towards the high end. 

Ken

[Jim Hoffman]

Ken,

I said your stated approach is fine for a sport flyer.  Your approach included not hollowing the OB tip block.


If you ever plan to building high end stunt models as you state, I would recommend you consider the weight of your OB tip; hollowed vs. unhollowed.  If the OB tip is heavy enough, you will end up with tip weigh on the inboard tip.  If you are confident that the un hollowed OB tip is not too heavy and you will not need IB tip weight, go ahead and save the time of don't hollow the OB tip.  Or do a partial hollow.

[FLOYD CARTER]

Weight is weight, whether it is excess balsa or lead. 

[Steve Helmick]

While I agree completely with Jim and Ty, from experience, I will add that you do NOT want to mount your adjustable leadout guide (only) onto a soft inboard tip rib.

I had the one on my SV-11 break loose, and found they fly really badly with the adjustable leadout guide rattling around in the tip! I had to dissect bottom of the block tip and make repairs. My solution was to add a vertical piece of 3/16" square at both ends, tying into the top and bottom of the hollowed tip block. I think this would be a fine idea on a new build.

Also agree with Floyd, except that if you use heavier wood throughout the outboard wing, you ARE adding to the GVW. 

  Steve

[Ken Culbertson]

While I agree completely with Jim and Ty, from experience, I will add that you do NOT want to mount your adjustable leadout guide (only) onto a soft inboard tip rib.

I had the one on my SV-11 break loose, and found they fly really badly with the adjustable leadout guide rattling around in the tip! I had to dissect bottom of the block tip and make repairs. My solution was to add a vertical piece of 3/16" square at both ends, tying into the top and bottom of the hollowed tip block. I think this would be a fine idea on a new build.

Also agree with Floyd, except that if you use heavier wood throughout the outboard wing, you ARE adding to the GVW. 

  Steve

Been there, Done That!  I had a brand new Brodak guide slip off because that tiny washer they use didn't seat.  Fortunately it was a warm up flight at a contest and I did have some scotch tape to cover the surgery.  I put mine as close to the actual tip as possible in the tip block.

I am convinced to lighten the wing but I do think I will not hollow the outboard tip block.

Thanks for the help.

Ken