WIX Archives

Re:Aircraft grounded from lack of 115/145

Posted by Larry Kraus on Thu Oct 30, 2003 04:46:55 PM

A question was asked concerning R3350 Turbo Compound engines operating on 100/130 or 100LL.I checked in our DC-7 Operations Manual to get the original 115/145 take-off power setting for Wright 972TC18DA2 engines.It shows for 3250 H.P. the setting is: 56.5" or 265 BMEP at 2900 RPM.With 100/130,we're allowed (at sea level): 53" or 234 BMEP at 2900RPM for 2880 H.P. We also have an STC to use military equvalent engines from C-121/WV-2 Connies.We can use R3350-34,-42,-91,or -93 engines.The -42 max. MAP is 51" and the -93 max. MAP is 52" with 234 max. BMEP and 2900 RPM each.They must have a slightly different blower ratio.I'm not sure what the max. 115/145 MAP and BMEP were on the 972TC18EA series engines used on the DC-7C, but they are de-rated to the same 2880 H.P. settings as the DA's.With 100/130 or 100LL,the DC-7 also must disable the high blower controls as well as deactivate the spark advance mechanism.On the ex-United DC-7 that I fly,the max. take-off weight was reduced from 122,200lb. to 113,800lb. and revised performance charts supplement the originals.Our airplanes are still Transport Category rather than Restricted.As for 100LL,we cautiously use the 100/130 settings and watch the head temps.

Follow Ups: