Tests of Several Model Nacelle-Propeller Arrangements in Front of a Wing
Abstract
An inve tigation was conducted in the B.J..O.J.. 20- foot wind tunnel to determine the drag, the propulsive and net. efficieno1ea 1 and the coolinc characteristics of several scala-model arran~ementa of air-cooled radial-ancine nacelles and preaent-da:r propellers in front of an 18- percent-thick, 5- b:r 15-foot airfoil. Investigations of like arran~ementa aimulatin~ the ~eometric proportions of airplanes in the 20,000-pound wei ht classification have been conductod b:r the N.J..C.A. and the results are summarized in previous reports. This report deals with an inveati~ ation of winc4nacelle arrangements simulating the geometric proportions of airplanoa in the 40,000- to 70,000- pound woi~ht classification and havinc the nacelloa looatod ln tho vicinit:r of the optimum location determined from the earlier testa. Two 3-bla.de propellers with diamotera of 36 and 48 inches, reapectivel:r, wore oach tested in conjunction with a 12-inoh-diamoter nacelle in three positions in front of the win~ and with a 16-inch-diameter nacelle in aiz poai tiona in front of the wing. Lift, dra~. coolinc-air flo~, and propeller characteristics wore determined for each of the arrnncementa. Comparisons on the basis of net effi aieno:r between the various arran~ementa indicated that, for h1ch-apeed and cruis1nc conditions, the moat-favorable location for a tractor nacelle-propeller arrancement of the t:rpe tested wna with the thruat azia on the win~ center line and with the propeller between 15 and 30 percent of the chord forward of the leadinc edgo of the wine. The ioaa in not effioiono:r throu~h tho uae of either laresdiameter encinea or nacelle installation& hnvin~ a hich lnterferonce drac is cloarl:r indicated. In certain caaoa, the.action of the propeller slipstream on tho flow pnttern over the wine-nacelle arrangement ma:r be such as croatl:r to influence the cooling qualities of a ~ivon wine-nacelle-propeller arrangement.
Document Details
- Document Type
- Technical Report
- Publication Date
- Sep 01, 1939
- Accession Number
- ADA801478
Entities
People
- James G. Mchugh
Organizations
- National Advisory Committee for Aeronautics