MPC T15/20 transition length?
 

Hello All,

Does anyone here know the length of the MPC T15/20 balsa body tube adapter (they called it a coupler--it was Stock Number 3-1601, see: http://www.ninfinger.org/rockets/nostalgia/74avi10.html )? There is a "before decal-ing/after decal-ing" photograph (Figure 21, on page 60) of a custom-made (using MPC/AVI parts), scale-like model rocket (made using 20 mm and 15 mm body tubing) in the 1977 edition of "The New Model Rocketry Manual," by G. Harry Stine. It looks like the T15/20 balsa coupler ^might^ be 1" (or maybe exactly 25 mm?) long, but the picture was taken from a slightly elevated angle, so accurately measuring its length directly off the rather small image wouldn't be easy.

Many thanks in advance to anyone who can help!

The following Adapter table is from the 1969 MRI catalog, which is the predecessor of MPC/AVI, but many of the parts were the same. This table shows the T15/20 balsa adapter length at 0.75 inches/ 2 cm long.

Kind regards,
Jeff Jenkins
aka: Faithwalker
NAR #46879 SR

Jeff, thank you very much for this information, and for posting the MRI catalog's table! (I had forgotten that MRI was the predecessor of MPC and AVI--cudgel my memory--but Asallam bless yours!) In the picture in Stine's 1977 book, the adapter does look almost "square" (nearly equal in height and maximum width; due to the camera angle, it's hard to tell by looking whether the height or the maximum width is the greater of the two dimensions), and since the lower body tube--and thus also the wider end of the adapter--was 20 mm (0.787") in diameter, it is in excellent agreement with the given length of 0.75" (2 cm) for the adapter.