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1/4 scale Slingsby Gull Type 1 build

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1/4 scale Slingsby Gull Type 1 build

Now that winter is approaching and I'm out of the build, fly, repair, fly, repair cycle, I've going to scratch build a 1/4 scale Slingsby Gull Type I glider vintage 1939. I purchased plans for a 120 in. version, converted them to CAD, made a few changes for scale fidelity, and decided to scale it up to 1/4 scale. It's sooo easy once it's converted! This gives a wing span of 149 in. I'm projecting the the weight to be 7-8 lbs which will give a respectable 10-12 oz/sq/fy wing loading. Just the perfect weight for Tow Dog's new 1/4 scale CUB. Wonder how good my weight guestimate will be? Stay tuned. Here's a link to the full size glider now in the Soaring Museum on Harris Hill at Elmira, NY which I will try to replicate: http://www.scalesoaring.co.uk/RCSD/pdfs/KirbyGull/N41829.pdf
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1/4 scale Slingsby Gull Type 1 build

Good luck on your pending build. That is indeed a beautiful bird.
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1/4 scale Slingsby Gull Type 1 build

Thanx, Jim. Yes she is. That era produced, in my opinion, some of the most beautiful gliders ever designed. Except for some major progress pictures and descriptions, I don't plan on giving a blow by blow account of the build. That's already been done much better that I ever could with this build thread of a 1/3 Slingsby Gull by a master craftsman. http://www.rcgroups.com/forums/showthread.php?t=1101290 For the most part, I'll use similar building techniques, just noting major differences for each component in this build log.
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1/4 scale Slingsby Gull Type 1 build

Outstanding, Bob! It will be so graceful to watch this fine sailplane, soar and wheel about in the fine spring air.

Onward and Upward.
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1/4 scale Slingsby Gull Type 1 build

I couldn't have said it better me self, Randy. At least I don't think I will be beating you back to the field to land after release like it is now with the Salto!
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1/4 scale Slingsby Gull Type 1 build

No Sir, this ship will be a floater for sure. It will be the most elegant glider to grace the skies at the MMAA field.

Onward and Upward.
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1/4 scale Slingsby Gull Type 1 build

Oh that gull wing should be an interesting build. It'll make a really wonderful looking sailplane and with that wing loading it should be a joy to fly. Have you picked an airfoil yet, or will you use whatever they have on the plans? Looking at the web site you show above, I remember when studying for my A&P that I had to build up some wooden ribs like those in the full scale Gull. I actually enjoyed that.

Thermals---I need thermals!
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1/4 scale Slingsby Gull Type 1 build

Bob, that really shows the construction well. On page 80 was a standard Cirrus right next to the gull. This was my first glider, the Sterling 87 inch wingspan Cirrus. Neat stuff. Thanks.

Onward and Upward.
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1/4 scale Slingsby Gull Type 1 build

Yep, I almost would have paid the folks that restored that Gull to help work on it. I spent a few years in upstate NY in the late 70's about 2 hrs away from Harris Hill and used to take a trip up there now and again just to drool over the exhibits in the museum! At the time they had a Minimoa and a Baby Bowlus on display. Many active full size glider clubs in the area. Beautiful country, but the weather really sucked for soaring. Very overcast most of the time. I wish I had the skills, patience, and time to replicate the full size wing rib construction. They will be good 'ole sheet ribs. I will not use the airfoil shown on the plans which looks like just a plain Clark Y. It will be a 15% E214 for the inboard 5 ribs where the wings joiner box will be and a 12% E214 for the rest of the wing. With a planned 3 degree twist for the last 6 ribs of that very narrow tapered tip. The E214 profile is very close to the scale shape, and I have had very good results using it. The HQ 3.5 seems to be the large scale RC glider airfoil of choice right now, but my analysis using the Profili application shows about a 15% better L/D with the E214 in the RN that I think this thing will be flying in.
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1/4 scale Slingsby Gull Type 1 build

Wow, tech talk! Dr. Helmut Quabeck airfoils and Reynolds Number efficiency. Now there's something the Soarheads can chew on!

Onward and Upward.
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1/4 scale Slingsby Gull Type 1 build

Nice to see someone did their homework. Good choice to substitute those for the Clark Y. I can't wait to see this go together.

Thermals---I need thermals!
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1/4 scale Slingsby Gull Type 1 build

Mostly framed up. Some wing sheeting, leading edge carving, ailerons, and canopy molding left to be completed. Pleasantly surprised at the weight as shown in these pictures at 4.5 lbs and it is not very tail heavy. It balances within the root cord anyway. Pictures on the way.
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1/4 scale Slingsby Gull Type 1 build

I'm very interested in how this build is going and what the framework looks like. Any photos yet? It sounds ambitious. Large scale sailplanes are so impressive.
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1/4 scale Slingsby Gull Type 1 build

Oops! Sorry, couldn't get pics uploaded and got distracted building and stuff. More progress from last post with canopy and frame completed, wing leading edges carved and one aileron left to complete. Will take additional pics and try harder to get them uploaded. I get the pic file info filled in, click upload, and into the bit bucket they go. Help!
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1/4 scale Slingsby Gull Type 1 build

I'm just doing a test post of a photo to see if I have any more luck. [br][br]

Thermals---I need thermals!
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