Talk:Pratt & Whitney R-1830 Twin Wasp/Archive 1

Archive 1

Use in DC-3

The DC-3 Dakota page lists this engine as the most used one in the aircraft. This page does not list the DC-3 as a major application. Guess this needs to be added after verification..Deepak23 (talk) 04:03, 27 May 2010 (UTC)

SFC

The quoted specific fuel consumption (sfc) of 1.0 lb/hp-hr is way too high, at least for cruise. It may be accurate for takeoff condition where the engine is operated very rich. For cruise, it would not have been over 0.5. Even in WWI, the Curtis OX-5 was 0.53 at optimum cruise. The Wright R-3350 was 0.38 at optimum cruise. Fnj2 16:30, 25 August 2007 (UTC)

Swedish-built Twin Wasps

Swedes copied Twin Wasp during WW2 and produced it without any beforehand acquired license. They used it in own fighter production. Finland used 1065 hp R-1830SC3-G in VL Myrsky -fighters (50 in all) (and Curtiss Hawk -fighters (45 in all), too) but Finland bought motors from Germany's booty storage, located in France. None Swedish-built Twin Wasps sold to Finland! Myllyre (talk) 12:28, 21 October 2009 (UTC)

Link to Pratt & Whitney

... no 1830 site. — Preceding unsigned comment added by 87.123.158.217 (talk) 11:41, 30 December 2011 (UTC)

On the is page, the SBD Dauntless is listed as one of the aircraft that used the R-1830 Twin Wasp. I believe this is incorrect and the Dauntless should be removed from the list. I can't find any reference showing the Dauntless using the R-1830. Lpdwyer (talk) 20:08, 16 January 2013 (UTC)

Agreed, appears to have been entered in error, according to a reliable source the Dauntless used the Pratt & Whitney R-1535 for early versions and the Wright R-1820 for later aircraft. Nimbus (Cumulus nimbus floats by) 20:44, 16 January 2013 (UTC)

Reduction Gearing Spec Needs Correction

The two R-1830-92 engine plates on the C-47 at Palm Springs Air Museum clearly state that the reduction gearing is 16::9, not the 2::3 shown in this wiki. I have photos as evidence.

From an engineering perspective, overdrive gearing would make no sense in this application. The source for the specs in the wiki does not appear either reliable or comprehensible.

Pratt & Whitney R-1830-92 Engine Identification Plate.

Pratt & Whitney R-1830-92 Engine Identification Plate

Please advise best course for correction. 1peterk (talk) 14:37, 31 March 2023 (UTC)

Engine article specification sections usually specify which variant of the engine it is describing, in this case it is the R-1830-S1C-G (in parentheses in the section header). The photographs relate to a different variant, the '-92'. Photos of data plates can not be used as a source on Wikipedia, neither can museum placards, that would be original research. There are several types of reduction gear (planetary/epicyclic and spur are two) for the R-1830 with different reduction ratios. One of the better sources are the FAA TCDS (Type Certificate Data Sheets), the ratios of 3:2 and 16:9 are listed. A contemporary Janes source gives ratios of 0.667:1 and 0.5625:1. Another contemporary source gives 0.56:1, 0.67:1 and 0.316:1. I would say that the figure in the article is correct but reversed in convention (three revolutions of the engine for two of the propeller).

There are far more accessible reliable sources than the one cited here, it is a remnant from the early days of Wikipedia. If I get time I will check the specifications/variant and adjust the article to suit. Nimbus (Cumulus nimbus floats by) 15:25, 31 March 2023 (UTC)

That was helpful. TCDS A-669 shows the 16::9 for both the mentioned variants.

http://www.douglasdc3.com/faa/a-669.pdf 1peterk (talk) 15:44, 31 March 2023 (UTC)

Which TCDS says 3::2? 1peterk (talk) 15:50, 31 March 2023 (UTC)

My browser is rejecting that as a security risk, the TCDS are held by the FAA at https://drs.faa.gov/. I will work through this in good time.Nimbus (Cumulus nimbus floats by) 15:53, 31 March 2023 (UTC)

FAA was a little harder to link to the precise doc. But it's still TCDS A-669 for the DC-3 with the P&W. 1peterk (talk) 16:00, 31 March 2023 (UTC)

Updated to use FAA link. Includes the FAA URL and the document title: TCDS A-669. 1peterk (talk) 16:30, 31 March 2023 (UTC)

We only give figures for the variant described to avoid a sea of confusing numbers, 2:3 hasn't been corrected, the new citation links to a blank search page. Engine types have their own TCDS, the R-1830 military range is TCDS TC 5E-4. Nimbus (Cumulus nimbus floats by) 21:19, 31 March 2023 (UTC)