Hip Pocket Builders' Forum

Outdoor Free Flight Forum => Power => Topic started by: flydean1 on July 08, 2019, 11:59:17 AM



Title: Four hooks or two
Post by: flydean1 on July 08, 2019, 11:59:17 AM
This applies more to Power models due to their greater weight and flying speed.

I have long theorized that there was a structural advantage to spreading out the load on the wing center section over a wider area than just the center joint.  Moving the rubber bands to either side of the centerline, I thought would ease the strain on DT landings, and the occasional DT under power.

I would build a wing platform that supports the center to either side, and pass dowels or CF rods under the edge to hold the wing.

However, I see that many successful Free Flighters use a pair of hooks passing the rubber bands right over the center joint, or center of wing on flat panel models.

I tried to attach a picture of one of my T-Birds as an example, but I have tried 3 time with no success.

Looking to hear from others on the subject.

So what is it, four hooks or two?


Title: Re: Four hooks or two
Post by: Konrad on July 08, 2019, 01:15:02 PM
Not sure I understand the question. But we use centerline attachments to lower the drag to increase the performance of the model. I think most of your question with structure would depends on what or how the wing center joint or joiner are implemented.
Drag is what kill performance. Weight kills performance because the added lift required induces drag.

As to loading photos make sure the size of the photo is 400kb or less and use file formats like jpeg. I think there are detail on the site on how to do this.

P.S.
I like to use nylon bolts rather than rubber bands both for aerodynamic concerns and structural reasons. Rubber bands add drag and often cut through the leading edge and trailing edges. Properly sized and torqued nylon bolts will shear with little or no damage to the airframe if the two are designed to separate (not held captive with fairing and such. Rubber bands were a poor idea in the 30's and with the advent of plastics one might want to look at nylon shear bolts for a much more practical solution.


Title: Re: Four hooks or two
Post by: danberry on July 08, 2019, 08:09:01 PM
You're over-thinking things.


Title: Re: Four hooks or two
Post by: Konrad on July 08, 2019, 08:43:50 PM
Who, myself or Flydean?  ::)

All the best,
Konrad


Title: Re: Four hooks or two
Post by: danberry on July 08, 2019, 11:31:55 PM
Who, myself or Flydean?  ::)

All the best,
Konrad

Dean