I have read this story, and I remember that the fake anti-gravity device
is presented to the scientists as a backpack —
like a jetpack, but without jets.
So I threw the word “backpack,” along with the others, at Google.
I found Alec Nevala-Lee’s Wordpress site
on the first page of the Google results.
See in particular this section, which describes the story
and confirms that it is “Noise Level” by Raymond F. Jones,
published in the December 1952 issue of Astounding (#18).
This page includes a couple of illustrations from the story, AND …
it links to The Vinnie Vincent Fan Forum,
which contains the complete text of the novelette.
Here are some excerpts:
… Dunning rose in a rather steep arc and levelled off.
Against the background,
he seemed about as high as the roof of the hangar beyond.
For about a hundred feet he drifted slowly, then accelerated his pace. …
Abruptly the screen flared.
A puff of light exploded from the pack on Dunning’s back.
For a terrible moment he seemed suspended in an attitude of violent agony.
Then he plunged like a dropped stone.
‘The remains of the device are here for your examination.
So far, we see only burned and bloody wreckage in it.
‘Dunning’s quite evident paranoia was carried out in an utter lack of notes. …
… We have to duplicate that work of Dunning’s.
He threw the main power switches and then adjusted slowly a number of dials.
Almost imperceptibly, and without wavering,
the enormous disc-like mass rose in the centre of the shop.
It hovered without visible support three feet above the floor.
A couple of notes:
- Oddly, the text is accompanied by an image
of an Astounding Science Fiction cover that says “May,” without giving a year.
- The text looks like it might have been OCR’ed —
I saw a few one-character errors.