Craftsman: Ramon Hoagland
Knapp Collection #: 740
Catalog #: 2023.2.6
Contributor: Paul Knapp
This Bruce Macbeth inline four engine is 13.5″-long, 12″-wide, 11″-high, and weighs about 20 lbs.
Craftsman: K&B Manufacturing; Premium Manufacturing
Knapp Collection #: 616-2
Catalog #: 2019.33.14
Contributor: Paul Knapp
A special version of the Torpedo Jr. was created for a promotional model airplane produced for the LA Times Newspaper, circa 1951.
Craftsman: Roger Butzen
Knapp Collection #: 755
Catalog #: 2024.5.2
Contributor: Paul Knapp
This Caloric hot air engine was built by Roger Butzen of Texas.
Craftsman: Ron Bement
Knapp Collection #: 496
Catalog #: 2016.44.7
Contributor: Paul Knapp
This Challenger flathead V8 was custom built by Ron Bement. Ron’s version includes several innovations and modifications not found in conventional Challenger engines.
Craftsman: Dick Pretel
Knapp Collection #: 589
Catalog #: 2019.11.2
Contributor: Paul Knapp
The only part of this engine typical of the Challenger V8 is the crankcase; everything else was machined from 7075 aluminum, steel, and stainless steel bar stock.
Craftsman: Ed Miller, Mike Gombert
Knapp Collection #: 593
Catalog #: 2019.11.6
Contributor: Paul Knapp
This Challenger flathead V8 engine was built by Ed Miller (WY) and Mike Gombert (CO). Typical of Ed’s engines, this Challenger is designed to burn methanol on spark ignition.
Craftsman: Roger Butzen
Knapp Collection #: 777
Catalog #: 2024.5.16
Contributor: Paul Knapp
Roger Butzen built this Challenger V8 in 2000. The engine includes his custom-designed Chevy 283 overhead valve conversion and a Roots style supercharger.
Craftsman: Bachtold, Thoms, and Dettrick
Knapp Collection #: 08
Catalog #: 2011.27.1
Contributor: Paul Knapp
This Challenger V8 prototype engine is 12″-long, 12″-wide, 14″-high, and weighs 25 lbs. The engine was finished in the mid-1960s.
Craftsman: Merritt Zimmerman
Knapp Collection #: 10
Catalog #: 2008.10.4
Contributor: Paul Knapp
1/4 scale model built by Merritt Zimmerman, circa 1989, L=19″, W=8″, H=10″
Craftsman: Merritt Zimmerman
Knapp Collection #: 34
Catalog #: 2008.10.9
Contributor: Paul Knapp
Merritt Zimmerman produced his own castings to build 75 of these 1/6-scale Cirrus engines (glow ignition).