I do not understand the pressure tap being used to pressurize the outside of the bladder

A fuel tubing bladder requires no addition support

A balloon tank perhaps....confused

First a TeeDee 049 does not really need any break in and will run at 85% of full rpm right out of the box...two or three flights at 25% nitro and 20 % castor will get these precision engines near peak power.... 35% to 60% nitro is usable but just destroys the piston and rod

To run pressure bladder, do yourself a favor and make sure about the NVA...stock Cox part was NOT fine thread...and second favor either plug the pressure tap or use it as designed to pressurize a HARD tank

Texas timers sells the 128TPI NVAs http://www.texastimers.com/

Make up a true pressure bladder...see Texas Timers excellent "how to" on this subject

Check out other sources if you please such as CoreHouse ( Phil Cartier), good bladder stuff, or Doug Galbreath ( nelson heads and plugs)

Cox TeeDees are exceedingly difficult to start and fly with a hard tank but thousands of folks figured out how in the 60s~70s....(I never learned how to hold my mouth properly and gave up...bladders work for full tank no flame out flying)

Most bestest method for reliable full tank flight with the TeeDee was KK ( Kirn Kraft) or other Fine thread NVA and pressure bladder using surgical or fuel tubing

I own 21 TeeDee/Medallions and have 7 in service on 1/2a combat wings

2 inches of bladder, fittings, pinch off device, 25% Sig 1/2a fuel...Galbreath head and Nelson plug....all start second flip hot or cold