Project Tip Tow ...

[Mark Allen M]

The Wright Air Development Center evaluated wing tip coupling with a Boeing B-29 Superfortress and a pair of Republic F-84D Thunderjets as a means of extending the range of escort fighters under the auspices of Project Tip Tow in 1950.

https://www.youtube.com/watch?v=30d59njxIMw

[JohnB]

The rest of the story...

Initial trials were done with a C-47 (42-23918, used in several Wright Patterson trials) and a Culver PQ-14B (44-68334).
Despite wing movements (and I suspect wingtip vortices with such a light craft...even from a C-47), the proof of concept tests proved its feasibility, eventually 231 couplings were made with a total of 28.5 hours of top tow time.

Then the program moved into B-29A (45-62093) and two F-84Ds (48-0641 & 0661) in 1950. By April 1953 a new auto-stabilization system was installed. In one of the first tests, when the system was activated, the F-84 rolled over and struck the B-29s wing.
Both aircraft and all crew were lost.

When we think of tests pilots we tend to think of the men testing fighters at Edwards or Pax River. But remember, there were a lot of risky tests that didn't necessarily have to do with new types.
Remember the crews lost during those tests.

[quemerford]

Test pilots also include those who flew daily acceptance sorties for the thousands of production aircraft that have been manufactured over the years. Sometimes the difference in standards between plants producing the same aircraft was noticeable and so those test pilots really were often flying into the unknown.

[Larry Kraus]

There is an excellent book on this subject available in both paperback and pdf formats for a reasonable price.

2CE644E5-0EDD-474F-B053-23E155B0B2F2 by tanker622001, on Flickr

Some pictures from this book. These happen to be the pdf version. I have it in both formats.

B5F03D74-AB6F-405B-83C5-8B86249680A5 by tanker622001, on Flickr

7C5C761D-54D2-4444-83A0-8D2BDAFBD049 by tanker622001, on Flickr

74876A7E-7C01-4786-9FF1-C065C7B65737 by tanker622001, on Flickr

[bdk]

That last one wit the Culver looks pretty sketchy!

[JohnB]

I don't recall seeing a Culver with post-1947 USAF markings before.

The C-47 looks well worn.

[marine air]

Guessing the serial number and paint, that it’s a C-47A? Yes, there were a handful of airplanes that made it to the Air Force; PT-17s, BT-13s, etc. I think there may have been a few PT-19s andBamboo bombers. At some point the USAF wanted to get the wooden aircraft out of the inventory. I think the Stinson L-5 made it until either 1960 or 1965( can’t remember)

[JohnB]

marine air...
I asked a similar question here a couple of years ago.
On paper, the Cessna twin was surplused in '49...but I have never seen one in USAF colors.
Likewise, I can't say I have seen a Stearman or Vultee in post-47 colors.

I have read that last L-5 in service was bought surplus in 1957 and used to tow gliders at the Air Force Academy. So yes, an L-5 did survive in service that long, but not in "regular" service. It remained in service long enough that it became a U-19 in 1962 when the "L" series disappeared...The L-20 became the U-6, L-19 became the O-1, L-27 became the U-3, etc.

[Chris Brame]

There was an A-20 that hung on as a squadron hack in Occupied Japan into late 1948; hope to find a photo.