k-pax
the original question was about fuel burn with a gear out, sorry about slight drift but if you research boeing 377,b17,b29 you will find something lalong the lines of - after t/o if you can`t get all the gear up, you have a big prob i remember b377 coming out of mexico city must be around 88 or89 had the mexican equestrian on board cant remember where they where going, a/c took off ok then one of the gears refused to come up - whole plot crashed on a motorway, very messy the capt i think was one of the survivors iirc rick more? its a long time ago got pissed since then!
same reason key bird had an aux gen in the back, extra pwr to get the gear up
good luck gs.