Update
I received the scans and wanted to share a few to show the level of detail in Gus' plans. Looks just like a set of model airplane drawings with complete pattern templates.
Aileron Construction Detail.
Vertical Fin and Rudder Construction.
Stabilizer and Elevator Construction and Hinging Detail.
Sure looks like it would make a fun build and capable flyer.
A couple of years ago there was a thread at RC Groups by several guys interested in the Gus Briegleb-designed BG-12. It's an interesting sailplane with impressive performance for a 1956 home-builders design and kit. Last year on my visit toTehachapi I was fortunate enough to help Raul Blacksten remove his ship from its trailer and assist in assembly. I took a few photos but nowhere near enough time to do a full study for drafting plans for a model.
Then a couple of months ago, Herbert Eberbach who has completed several build logs here expressed interest in the Briegleb and coincidentally, Mark Nankivil emailed me just a week ago offering me a set of blueprints given him by Wabash Valley Soaring Association pilot Jim Croce. The prints arrived a couple of days ago, more than 30 sheets I think and they are impressive. I agree with Mark and Herbert that it will make a great scale sailplane model and my work in developing a kit has just been shortened by weeks.
Raul Blacksten's BG-12B at Tehachapi, CA being transferred to its new owner and assembled to brief him on the process.
Here are the specifications and brief history courtesy of the Sailplane Society of America Sailplane Directory:
Specifications-BG-12BD
Span 15.24 m./ 50 ft
Area 13.1 sq. m. / 141 sq.ft.
Aspect ratio 17.7
Airfoil NACA 4419R, 4406R
Empty weight 227 kg. / 500 lb.
Payload 113 kg. / 250 lb.
Gross weight 340 kg. / 750 lb.
Wing loading 25.95 kg. / sq. m. / 5.3 lb. / sq. ft.
Performance
L/D max. 34 90 kph/ 49 kt/ 56 mph
Min. sink 0.69 m/s / 56 fps / 76 kt
76 kph/ 41 kt/ 47 mph
Other
Country of origin USA
Designer William G. Briegleb
No. of seats 1
No. kits sold about 350
No. in the U.S. approx. 75
The BG-12 series has established an enviable record as a homebuilt sailplane with around 350 kits or sets of plans having been delivered to customers. The prototype flew in 1956 using a modified BG-6 fuselage. The –12A production version has a 15% thick three-piece wing. A lighter two-piece 18% thick wing was developed in 1963 as the –12B. Both have flaps for glidepath control. One flapless –12C model was built with a two-piece 15-meter span wing with air brakes to meet FAI/OSTIV Standard Class requirements. The –12BD model eliminates three degrees of wing twist, accomplishing the same effet by an aileron linkage applicable only in the low-speed range.
The Briegleb BG-12/16, which first flew in 1968, uses a new lower-drag fuselage topped off with a swept-forward tail. The horizontal tail surfaces are of thestabilator type including two anti-servo tabs to produce good stick feel. L/D max. is 36.
A number of modifications were incorporated by individual kit builders. One example is the Niedrauer NG-1 which has a BG-12/16 fuselage with a –12B tail and cockpit depth reduced by 9 in /23 cm to 34 in /86 cm, and lengthened to accommodate the pilot in a semi-reclining position. Specifications are for the BG-12BD.
Here are several other interesting links to information and photos of the Briegleb:
Paul's Glider Home Page - Great images and commentary on BG-12/16 owned by Paul R. Jorgenson.
Raul Blacksten's BG-12B - A earlier photo of the sailplane shown above.
just wanted to say thank you. This is a great site and whilst i should be working I've been reading for almost an hour :)
Posted by: Home Builders Melbourne | September 12, 2010 at 07:49 PM