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Speed,Combat,Scale,Racing => Rat Racing and Team Racing => Topic started by: bill bischoff on October 02, 2015, 08:21:35 PM
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Perhaps one of the biggest hurdles involved in building a Sport Goodyear is carving the wing. Recently, I have found a way to clear this hurdle with a minimum of effort. It only applies to constant chord wings, such as found on the Buster, Bonzo, Zipper, Stardust, and a whole plethora of Cassutts.
The good folks at Brodak sell a replacement wing for their Flight Streak Trainer for $16.00. (It is listed in the paper catalog, but I could not find it online). The wing is one piece, 6" chord, about 37" span, and a bit over 3/8" thick. It has a pre-carved flat bottom airfoil, with a 1/8" thick trailing edge to accomodate the Streak Trainer's fixed flaps. It is the top wing in the photo.
I personally wanted a wing with 6 5/8" chord for my new BooRay. First, I cut the wing apart 2" from the leading edge, and added a 1/4" x 3/8" spruce spar. This increased the chord by 1/4". Then I added a 1/8" x 3/8" spruce trailing edge, which increased the chord to the desired 6 5/8". I also cut 1/4" off the leading edge, and replaced it with 1/4" x 1/4" spruce for strength and impact resistance. This is the middle wing in the photo.
Once this was done, the spruce leading and trailing edges were shaped, and the high point of the wing sanded to blend everything together. The bottom wing shows the finished airfoil.
If a narrower chord is needed, a section of balsa may be removed from the high point area of the wing. For example, cut the wing leading edge at 1 3/4", then cut 5/8" off the front edge of the back part of the wing. Add the 1/4" spar and 3/'8" trailing edge, and you are back to a 6" chord. This would be appropriate on the Stardust, for example.
It will also be necessary to install some sort of hard point for mounting the bellcrank. I recommend the tapered maple spar/ bellcrank mount as featured on the Margaret June plans. This may be installed after the wing is assembled, but will be easier to fit and install before gluing the wing together.
Hopefully, this will be just what some of you need to start building your own Sportsman Goodyear racer.
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some pic's of the Boo Ray
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Good Job , Id made a few Cassutts whilst at school , had a K&B 15 R / 64 in one , if the memory serves .
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Good rendition of the BooRay, one of my favorite airplanes. HooRay for the BooRay!
MM
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ACTUALLY , for a Tapered wing , Cutiing the rear at a angle ( say 2 in at tips , 4 in at center for example ) for a straight L.E. G/Y wing
would get you the shape with a tapered spar , and a bit of blending in .
One racer shapes the wing , THEN cuts the T.E. to plan - leaving the cut going thicker outward . Shaving the underside flat to the top of the cut
from the high point aft under , gives it washout. Which improves the glide - so says he .
So your ' Blank ' is adaptable to most Id think . Thanks for the post Bill .
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Been waiting for decent weather for painting...
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Progress (thanks to 73 degree weather on Christmas eve!)
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I like it. Now to get mine done.
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It's finished. I hope to fly it on New Year's Day.
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Nice job once again Bill. Should be a winner. Darn, I wish I built as fast as you do. Any chance of posting a picture of the right side of the plane? Like to get a look at the details. Happy New Year to all! 8)
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Here you go, Pete. the details are pretty typical of the last several Sport GY's that I have built.
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Thanks Bill, simple and clean-I like it. Appreciate the tip on the pre-shaped wing as well. Carving/sanding a good airfoil in a wing has always been a challenge, whether it be for a hand launch glider or C/L racer. This helps. 8)
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Bill,
Sorry to be late to this game but I had been reading the racing posts and came across this one of yours. Good idea about the wing, two questions 1-How to get a copy of the Boo Ray plan? 2-Is Sportsman good year a AMA event so the rules are on the AMA site?
I live close to the Huntersville NC club and trying to get others interesting in Racing and this might be a simple way to get started especially if I build 2 or 3 models. Again Tks.
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Sportsman Goodyear is an unofficial event. The rules are on the Dallas Model Aircraft Association web site (dmaa-1902.org). These rules are being adopted by many clubs across the country. The popular engine is the ASP/ Magnum 15A. Until recently, these engines were available from multiple US sources. Now, the best deal seems to be from Just Engines in the UK. Engines are about $45 USD each. Shipping is also about that much, so best to order 3 or more!
The June 2015 issue of Model Aviation featured my Sportsman Goodyear construction article "Margaret June". Everything about the BooRay is similar, other than the actual outlines of the plane. I will email you a PDF of the BooRay plan.
Bill
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Bill,
Tks for the follow up. Will follow your advice.
Cheers.
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Bill: My Brodak catalog is MIA. When I called Brodak the person I talked to (I'm sure it wasn't Jan) had no idea what I was talking about. Would you list the part number from the catalog for the wing so the next time I call in an order I can point them in the right direction. Thanks! 8)
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Balsa B you are a mind reader and scholar. Thank you.
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Brodak catalog #19, page 35. Profile Flite Streak Trainer
For you scratch builders these items are available
..........Pre-Shaped Wing 16.00
(no part number listed)
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Thanks Bill, that will make it easier the next time I place an order. 8)
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Bill ,
I was able to order some today from Brodak for delivery later this week!!!
Again Tks.
PS NO update on the BooRay kit!