Diesel World - - Vintage Smoke Packard Dr-980 -

1,100-mile trip that used $8.50 of fur­nace oil. Packard ad­ver­tised fuel con­sump­tion of 0.40 lbs/hp-hr (about 8.8 gph) for a cruis­ing speed of about 90-100 mph. At full power the DR-980 used 0.46 lbs/hp-hr (about 14.8 gph). Packard stated the Wright J5 gasser de­liv­ered 0.60 lbs/hp-hr for (about 15 gph) at cruis­ing.

Packard man­age­ment was en­cour­aged enough to in­vest $650,000 in a new aero en­gine plant, pro­ject­ing 500 en­gines a month in pro­duc­tion by the end of 1929. Well, the plant got built and tooled up, but it wasn’t crank­ing out 500 en­gines per month by the end of 1929. In mid-fe­bru­ary 1930 Packard ran a stan­dard 50-hour cer­ti­fi­ca­tion test on en­gine #100, the first pro­duc­tion en­gine. It passed, and by March 6, 1930, the De­part­ment of Com­merce is­sued an ap­proved type cer­tifi­cate, the first ever is­sued for a diesel aero en­gine. Packard could be­gin to sell en­gines and an­nounced this on April 5 at the Detroit Air Show.

The early pro­duc­tion en­gines dif­fered from the six hand-built pro­to­type en­gines. The block was im­proved by adding rib­bing and the cylin­der head fea­tured but­ter­fly “chokes,” the in­takes of each cylin­der that ac­ti­vated to slow the en­gine when the throt­tle was brought to idle. After 10-15 en­gines were built that way late in 1930 a bar­rel valve ap­peared that re­stricted the valve port in a more el­e­gant way. The bar­rel valve also sig­naled a drop in com­pres­sion ra­tio from 16:1 to 14:1 and struc­tural im­prove­ments to the head. This ra­tio drop was part of an ef­fort to re­duce vi­bra­tion and so was a rub­ber-damp­ened pro­pel­ler hub, but nei­ther im­prove­ment com­pletely solved the prob­lem.

On May 28, 1931, a DR-980 pow­ered Bel­lanca Pace­maker set the world’s non-re­fu­el­ing record for fixed-wing air­craft, 84 hours and 33 min­utes. Wal­ter Lees, one of the pi­lots, said they had at least four more hours of fuel in the tank but landed due to ap­proach­ing stormy weather. For this mile­stone Packard would win the Col­lier Tro­phy, Amer­ica’s high­est aviation award, and the record would stand un­til 1986 and Dick Ru­tan’s record nine-day flight.

Packard in­stalled DR-980S into five of its own air­craft: the orig­i­nal Stin­son Detroi­ter, a Waco Taper­wing bi­plane, Buhl Air Sedan, Bel­lanca Pace­maker and Bird Model F. Sev­eral air­craft com­pa­nies tested Packard diesels. The big­gest air­craft to use them was the 184-foot air­ship De­fender, a Goodyear Model PA blimp on which a pair of DR-980S was tested from Novem­ber 1931 to June 1932. Ford briefly of­fered them as an op­tion on its Tri­mo­tor in 1930. The ex­per­i­men­tal Towle TA-3 am­phib­ian used a pair of Packard diesels in 1930. An­other ex­per­i­men­tal plane, the twin-en­gine Ste­wart M-2, briefly had Packards. The Verville Air­craft Com­pany tested one in an Air Coach. The Army Na­tional Guard tested Packards in two planes, the XPT-8A trainer and the XPT-8 ob­ser­va­tion air­craft. A Packard pow­ered Bel­lanca Pace­maker on floats, owned by Transamer­i­can Air­lines, left Detroit in Septem­ber of 1931 for the Shet­land Is­lands off the coast of Scot­land but dis­ap­peared. Weeks later, much of the plane was found afloat and it ap­peared to have landed in­tact. En­gine fail­ure was the pre­vail­ing the­ory.

Be­fore long, the “whiz bang­ness” of the en­gine soon faded in the cold light of re­al­ity. The DR-980 gar­nered a lot of neg­a­tive com­ments from test pi­lots. In one in­stance, a cylin­der hoop broke and the en­gine launched a jug, barely miss­ing the pi­lot. Pi­lots uni­ver­sally com­plained about the ex­haust fumes and more than a few re­fused to fly Packard diesel-pow­ered air­craft for this rea­son. The vi­bra­tion was re­ported as das­tardly, in a few cases re­sult­ing in air­frame dam­age. When the Navy took a late pro­duc­tion en­gine, num­ber 120, for a 50-hour dura­bil­ity test in early 1931, it failed three times and the test was ter­mi­nated. It was not rec­om­mended for pro­cure­ment.

 Roller rocker tips! Be­fore you startooo­ing and ah­hing, bear in mind they were com­mon in the era. Me­tal­lurgy and lu­bri­cants had not ad­vanced far enough to make rocker and valve tips able to with­stand that slid­ing mo­tion so rollers were com­monly used. You can’t see it, but in­stead of a big coil valve spring Packard used 12 smaller ones around the valve stem in­side the re­tainer cup.

 This is one of the early pro­duc­tion en­gines with a but­ter­fly in each in­take. Note also the lack of ex­tra rib­bing on the cylin­der head ver­sus the later pro­duc­tion en­gines. This would also be a high-com­pres­sion en­gine and is shown with the outer part of the pro­pel­ler hub in­stalled. Late in 1930 they be­gan build­ing the low-com­pres­sion bar­rel-valve en­gines.

 The bar­rel valve as seen from the in­let side. The bar­rel ro­tated to block in­let air to the valve port. No air fil­ters were used, so what­ever got past the prop could con­ceiv­ably get into the en­gine.

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