Sadly to conserve the rapidly diminishing ‘Attachment Memory’ in my account I’m unable to post pictures of all of NAM’s ‘engine test-bed’ airframes however I would note the following.

IMHO the most significant is Meteor FR.9 VZ608, which was the V-TOL test-bed for the RB.108 vertical lift engine and you can get a glimpse of her here.

I would also venture to add the following airframes to any list:

Ashton WB491 {Nenes}
Sycamore WT933 {hot & cold weather trials}
Canberra B2 (Mod) WV787 {Sapphire}
Meteor FR.9 (Mod) VZ608 {RB.108}

Plus two possible outsiders (depends on criteria applied) 😀

Luscombe Rattler Strike G-BKPG {???}
Zurowski ZP.1 BAPC 183 {???}

Full airframe list here!

Footnote to Mods how do I proceed when the attachment quota is reached?