News:



  • March 28, 2024, 11:33:17 PM

Login with username, password and session length

Author Topic: Wing Weight  (Read 1416 times)

Online Ken Culbertson

  • 24 supporter
  • Trade Count: (0)
  • Admiral
  • *
  • Posts: 6037
Wing Weight
« on: August 12, 2018, 12:25:39 PM »
Is there any rule of thumb for the uncovered weight of a wing with controls and flaps?  I have never weighed things while building but it seems I should be.  Current under construction 660sq" 64" span.  I don't need anything too exact.  What would be too light and what would be too heavy would be enough.

Thanks
Ken
AMA 15382
If it is not broke you are not trying hard enough.
USAF 1968-1974 TAC

Online Ken Culbertson

  • 24 supporter
  • Trade Count: (0)
  • Admiral
  • *
  • Posts: 6037
Re: Wing Weight
« Reply #1 on: August 12, 2018, 06:11:43 PM »
Hi Ken. Besides the obvious, "build lit as light as possible", I don't know of any.  I have build four of the Tom Morris wings in the past 7 months and they average out at 10oz, uncovered, undoped, with controls less flaps and two of these are sheeted Millinium wings. VERY light.  The two sheeted wings went on a profile P51B and the wing area was near 660 or more. In these wings every thing is made up of 1/16th 4 Lb balsa.  FWIW  D>K

Thanks a bunch. At least I have a reference point now!

Ken
AMA 15382
If it is not broke you are not trying hard enough.
USAF 1968-1974 TAC

Offline Air Ministry .

  • Trade Count: (0)
  • Admiral
  • ******
  • Posts: 4978
Re: Wing Weight
« Reply #2 on: August 12, 2018, 07:37:21 PM »
Or TWENTY Oz. for the pair of Bare Strega A R C wings .  :P with the controls removed , no flaps .  :-X

About 14 - 15 Oz complete , flaps'n'all , maybe not the gear . or TEN complete , if youre aiming for Number One . They Say .

Offline Matt Colan

  • N-756355
  • AMA Member
  • Trade Count: (0)
  • Admiral
  • *
  • Posts: 3440
Re: Wing Weight
« Reply #3 on: August 13, 2018, 08:32:48 PM »
The wing on my new plane, (64 1/2” span roughly 720 sq”) weighed 11.20oz with flaps and hinges on it ready to cover. This was my lightest wing I’ve ever built. My SV-11 foam wing with flaps at the same stage weighed 16.9oz and my Staris wing (slightly smaller, 57” 630 sq”) weighed 14.7oz.

Hope this helps get you a ballpark figure of what to estimate. My Staris ended up at 66oz and my SV-11 64oz. My new plane is on pace for 58-60oz ready to fly
Matt Colan

Online Ken Culbertson

  • 24 supporter
  • Trade Count: (0)
  • Admiral
  • *
  • Posts: 6037
Re: Wing Weight
« Reply #4 on: August 13, 2018, 10:26:18 PM »
The wing on my new plane, (64 1/2” span roughly 720 sq”) weighed 11.20oz with flaps and hinges on it ready to cover. This was my lightest wing I’ve ever built. My SV-11 foam wing with flaps at the same stage weighed 16.9oz and my Staris wing (slightly smaller, 57” 630 sq”) weighed 14.7oz.

Hope this helps get you a ballpark figure of what to estimate. My Staris ended up at 66oz and my SV-11 64oz. My new plane is on pace for 58-60oz ready to fly
Help a bunch.  I am at 11 w/o flaps and cap strips but I also did not hollow my outboard tip block.   I thought I was building "Miss Piggie" but it looks like I am on the low end of average instead.  First time this big since 1963 and in those days you didn't weigh stuff.

Ken
AMA 15382
If it is not broke you are not trying hard enough.
USAF 1968-1974 TAC

Offline L0U CRANE

  • AMA Member
  • Trade Count: (0)
  • Admiral
  • *
  • Posts: 1076
Re: Wing Weight
« Reply #5 on: August 16, 2018, 06:05:18 PM »
I've been cautioned that this isn't a cure-all, but it has proven a decent, safe start point...

When the model is ready to finish paint and the tip weight box is empty, assemble ALL pieces (engine, tank, wheels, etc.) and lay it upside down on a towel - fin and nose supported.

Put the reel with your intended lines halfway between fuse CL and inboard tip. Put an empty, identical reel, w/clips, etc., the same distance out on the outboard wing. The weights of the reels and clips cancel out. Only difference is the full weight of the lines in the inboard reel..

 Add tip weight at the weight-box location until the model is just about balanced (neither tip definitely falls to the table.)

Secure tip weight in the box, or epoxy it in if there's no box. Whatever, you can adjust as needed later.

What this does is balance the model spanwise on the fuse centerline for the half of line weight supported at the leadout guides. We support the other half at the handle. (Full weight at half distance = half weight at full distance, right?)

This is not final tipweight trim! Only flight can get that! This is  unlikely to be heavier than final trim. It does help, though. I had one very light profile with a fairly hefty head-out engine. This method found that some inboard tip weight was needed! Final trim confirmed it!

This is a 'do it until it is done' method, not calculating weights and distances. And it makes a safe start toward finding final tipweight.
\BEST\LOU


Advertise Here
Tags:
 


Advertise Here