# German WW II Torpedo Question **URL:** \ **Category:** Factual Questions\ **Created:** [September 30, 2002, 9:44am UTC](https://boards.straightdope.com/t/german-ww-ii-torpedo-question/130220 "2002-09-30T09:44:24Z")\ **Posts on this page:** 5\ **Page:** 1
**Author:** ![flertbert](https://avatars.discourse-cdn.com/v4/letter/f/e5b9ba/32.png) [@flertbert](https://boards.straightdope.com/u/flertbert)\ **Post date:** [September 30, 2002, 9:44am UTC](https://boards.straightdope.com/t/german-ww-ii-torpedo-question/130220/1 "2002-09-30T09:44:24Z")
I’ve been reading _ **German Secret Weapons of the Second World War** _ by Ian V. Hogg and on page 174 he writes > [@](#): > > The Junkers Jumo KM 8 engine was a brilliant technical achievement, consuming its own exhaust gases so as not to leave a telltale trail in the water, it was a 4.5 litre V-8 which developed 425 horsepower. Que? How did this work? Anyone know? ---
**Author:** ![ftg](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/ftg/32/2801_2.png) [@ftg](https://boards.straightdope.com/u/ftg)\ **Post date:** [September 30, 2002, 6:41pm UTC](https://boards.straightdope.com/t/german-ww-ii-torpedo-question/130220/2 "2002-09-30T18:41:49Z")
It used hydrogen peroxide, which exhausts steam which condenses into just water. Look at [this page](http://members.aol.com/pelzig/shusui.html). Search for “peroxide”. ---
**Author:** ![flertbert](https://avatars.discourse-cdn.com/v4/letter/f/e5b9ba/32.png) [@flertbert](https://boards.straightdope.com/u/flertbert)\ **Post date:** [October 1, 2002, 6:15am UTC](https://boards.straightdope.com/t/german-ww-ii-torpedo-question/130220/3 "2002-10-01T06:15:08Z")
You sure about that **ftg**? Because all I can find on the page is > [@](#): > > These applications dealt with rocket motors for missiles, not for flight. One of the researchers, Wernher von Braun, however, was more far thinking. Hellmuth Walter, working at the Germania-Werft, was tasked with devising a wakeless torpedo motor. But he was also battling the complexities of liquid fuel rocket engines. He began to use hydrogen peroxide to fuel the torpedo motor as when it decomposed, it was in the form of superheated steam which condensed swiftly in water, thus leaving no wake. No mention of the V-8 and if you’re using peroxide why not use potassium permagnenate since that’ll cause the peroxide to autoinginte and you’ll have a rocket powered torpedo and the Germans were already using that combination as fuel for the V-1 and other things. ---
**Author:** ![flertbert](https://avatars.discourse-cdn.com/v4/letter/f/e5b9ba/32.png) [@flertbert](https://boards.straightdope.com/u/flertbert)\ **Post date:** [October 1, 2002, 7:13am UTC](https://boards.straightdope.com/t/german-ww-ii-torpedo-question/130220/4 "2002-10-01T07:13:10Z")
There’s also no mention on the page that Hellmuth Walter worked for Junkers, and a google search turns up nothing along the lines of an ICE engine designed by Walter or mention of Walter working for Junkers. ---
**Author:** ![Sofa\_King](https://avatars.discourse-cdn.com/v4/letter/s/58956e/32.png) [@Sofa\_King](https://boards.straightdope.com/u/Sofa_King)\ **Post date:** [October 1, 2002, 3:08pm UTC](https://boards.straightdope.com/t/german-ww-ii-torpedo-question/130220/5 "2002-10-01T15:08:05Z")
I do know that by the end of WWII, the Germans had at least one non-operational [hydrogen peroxide-fueled](http://www.withhonourinbattle.com/walter_turbine.html) submarine. These machines anticipated the design of the nuclear submarine in that they shared the same objectives: a high submerged speed and air-independent operation in order to remain submerged for prolonged periods of time. That link offers a brief explanation of how the system worked: > [@](#): > > Walter achieved his remarkable results by using Perhydrol, a nearly pure hydrogen-peroxide solution, as an oxydizer. This was run through a catalysing system, which broke down the hydrogen peroxide (H2O2) into hydrogen and oxygen, in the process producing high pressure steam and oxygen at a very high temperature. The creation of the steam used up both of the hydrogen atoms and one of the oxygen atoms, leaving a free oxygen atom in the mixture. Since the temperature of the gases was hot enough to sustain combustion, diesel fuel was injected, which used the free oxygen atom. This increased both the heat and pressure of the steam. The steam was then used to power a turbine, which combined elements of both gas and Parsons (steam) turbine technology. Though I don’t see it in that article, I think the prototype also had a system for releasing O2 from the peroxide and carbon dioxide scrubbers in order to provide breathable air for the crew.