Phoebus A as a first glider

On Monday, April 16, 2018 at 9:29:56 AM UTC-7, wrote:
I have been thinking about the advisability of buying a 50 year old Glider and several things came to mind. There were 3, first generation ships, Diamont, Phoebus and 301 Libelle. Two of them used balsa wood wing core and the other didn't use any core at all (Diamont 16.5 & 18) and one used a wooden box spar (Phoebus). The next generation of sailplanes didn't employ any of these construction methods! The next generation (ASW-20, etc.) was built about 40% stronger after the LBA changed the strength requirements for their sailplanes. As an example, the Phoebus uses 3 layers of 4 ounce cloth in their fuselage (and wings) while the 20 uses a minimum of 3 layers (or more) of 6 ounce cloth in their fuselage. The question becomes, Is the Phoebus built strong enough? Yes, but the integrity of the wooden based box spar must not be compromised! What could compromise the integrity of the box spar? A ground loop that resulted in a split seam for a few feet. Pilot probably got out and was relieved to see the T tail still standing proud. He probably made a careful inspection, looking for any cracks and decided all's well, that end's well, right? A split seam in the box-spar can't be seen from the outside! Something else that could weaken a box-spar is wood rot, can't see that from the outside either. We know the ship has been stored in the rafters for 15 years, but how was it flown and stored before that? The ship may not be a bargain at any price!
I've been remembering the tragic crash of BG-12, that a new pilots dad had perched for his son. The kid made a high speed pass, like he'd seen the big guys do, then pulled on the flaps (probably going too fast), the inboard hinge of one flap gave way and took out the drag spar! That allowed the wing to twist and one wing departed the aircraft! Wood rot was found in the drag spar!
Buyer be ware!
JJ

When and where did the accident occur (I found 3 fatals involving BG12s, and none involved a high-speed, low-pass).

Tom

On Monday, April 16, 2018 at 2:57:24 PM UTC-7, 2G wrote:
On Monday, April 16, 2018 at 9:29:56 AM UTC-7, wrote:
I have been thinking about the advisability of buying a 50 year old Glider and several things came to mind. There were 3, first generation ships, Diamont, Phoebus and 301 Libelle. Two of them used balsa wood wing core and the other didn't use any core at all (Diamont 16.5 & 18) and one used a wooden box spar (Phoebus). The next generation of sailplanes didn't employ any of these construction methods! The next generation (ASW-20, etc.) was built about 40% stronger after the LBA changed the strength requirements for their sailplanes. As an example, the Phoebus uses 3 layers of 4 ounce cloth in their fuselage (and wings) while the 20 uses a minimum of 3 layers (or more) of 6 ounce cloth in their fuselage. The question becomes, Is the Phoebus built strong enough? Yes, but the integrity of the wooden based box spar must not be compromised! What could compromise the integrity of the box spar? A ground loop that resulted in a split seam for a few feet. Pilot probably got out and was relieved to see the T tail still standing proud. He probably made a careful inspection, looking for any cracks and decided all's well, that end's well, right? A split seam in the box-spar can't be seen from the outside! Something else that could weaken a box-spar is wood rot, can't see that from the outside either. We know the ship has been stored in the rafters for 15 years, but how was it flown and stored before that? The ship may not be a bargain at any price!
I've been remembering the tragic crash of BG-12, that a new pilots dad had perched for his son. The kid made a high speed pass, like he'd seen the big guys do, then pulled on the flaps (probably going too fast), the inboard hinge of one flap gave way and took out the drag spar! That allowed the wing to twist and one wing departed the aircraft! Wood rot was found in the drag spar!
Buyer be ware!
JJ

When and where did the accident occur (I found 3 fatals involving BG12s, and none involved a high-speed, low-pass).

Tom

Unfortunately it did happen at Tehachapi, Ca

When and where did the accident occur (I found 3 fatals involving BG12s, and none involved a high-speed, low-pass).

Tom

It was several years ago at Mountain Valley Airport in Tehachapi. I remember reading about it in Soaring, but I don't remember the exact year.

The accident occurred on August 26, 2000 at Mountain Valley Gliderport in Tehachapi, California and the glider was listed as a CABLE-BREIGLER BG-12BD.

Very sad.

Dan Armstrong
"DAN"

On Monday, April 16, 2018 at 4:20:51 PM UTC-7, wrote:
The accident occurred on August 26, 2000 at Mountain Valley Gliderport in Tehachapi, California and the glider was listed as a CABLE-BREIGLER BG-12BD.

Very sad.

Dan Armstrong
"DAN"

I couldn't find it because the accident glider was a BG-12BD and that isn't an NTSB search option (a persistent problem with the NTSB search query). The NTSB found that the pilot exceeded the flap-extended speed limit (no mention was made of wood rot). Wood rot is a serious concern; I once convinced my partners in a Citabria 7KCAB to sell the plane because wood rot had been found in some aircraft and ours was tied down outside. But this can be inspected for, so it isn't a deal breaker IF a proper inspection is done.

On the subject of high-speed, low passes: I have discouraged these for a long time. Part of my rational is it encourages low time pilots to try to emulate the maneuver who may not have the skill level to pull it off. And there is not a good reason for doing it to begin with.

Tom

On Monday, April 16, 2018 at 5:24:00 PM UTC-7, 2G wrote:
On Monday, April 16, 2018 at 4:20:51 PM UTC-7, wrote:
The accident occurred on August 26, 2000 at Mountain Valley Gliderport in Tehachapi, California and the glider was listed as a CABLE-BREIGLER BG-12BD.

Very sad.

Dan Armstrong
"DAN"

I couldn't find it because the accident glider was a BG-12BD and that isn't an NTSB search option (a persistent problem with the NTSB search query). The NTSB found that the pilot exceeded the flap-extended speed limit (no mention was made of wood rot). Wood rot is a serious concern; I once convinced my partners in a Citabria 7KCAB to sell the plane because wood rot had been found in some aircraft and ours was tied down outside. But this can be inspected for, so it isn't a deal breaker IF a proper inspection is done.

On the subject of high-speed, low passes: I have discouraged these for a long time. Part of my rational is it encourages low time pilots to try to emulate the maneuver who may not have the skill level to pull it off. And there is not a good reason for doing it to begin with.

Tom

Here is the report:
https://app.ntsb.gov/pdfgenerator/Re...Final&IType=LA