This is the place where the majority of the warbird (aircraft that have survived military service) discussions will take place. Specialized forums may be added in the new future
Sun Apr 12, 2020 11:14 am
Noha, think of it this way, a prop pulls a plane thru the air by rotation, the brits call it an airscrew for good reason, because that is how it works. with a single fin you have the air that the prop went thru pushing more on one side of the fin than the other, that will cause the nose to move to one side, which needs to be offset with trim, which is drag, some planes use a tab, others offset the vertical. On an Ercoupe, both rudders and fins are outside the diameter of the prop, so they are not effected by the prop wash. The reason a Coupe cannot spin is it cannot stall, nor can it be flown uncoordinated. Get too slow on a coupe and it comes down like a brick, but it is always under control as the ailerons are the entire wing trailing edge, if it can't stall, and you cannot fly uncoordinated, then it can't spin. The coupe can handle crosswinds that will ground most general aviation planes, Boeing even bought several Coupes to use to teach the crosswind landing technique of landing in the crab used on the 707 and later planes, as the Coupe had been landing that way since 1938.
Sun Apr 12, 2020 3:22 pm
Matt Gunsch wrote:Noha, think of it this way, a prop pulls a plane thru the air by rotation, the brits call it an airscrew for good reason, because that is how it works. with a single fin you have the air that the prop went thru pushing more on one side of the fin than the other, that will cause the nose to move to one side, which needs to be offset with trim, which is drag, some planes use a tab, others offset the vertical. On an Ercoupe, both rudders and fins are outside the diameter of the prop, so they are not effected by the prop wash. The reason a Coupe cannot spin is it cannot stall, nor can it be flown uncoordinated. Get too slow on a coupe and it comes down like a brick, but it is always under control as the ailerons are the entire wing trailing edge, if it can't stall, and you cannot fly uncoordinated, then it can't spin. The coupe can handle crosswinds that will ground most general aviation planes, Boeing even bought several Coupes to use to teach the crosswind landing technique of landing in the crab used on the 707 and later planes, as the Coupe had been landing that way since 1938.
Thanks, I really appreciate the explanation. That makes sense. (Also, good callback to the
other thread!)
I've always loved the Ercoupe, and twin tails in general. Not for any aerodynamic reason though, but just because they look cool!
Sun Apr 12, 2020 8:59 pm
The center of gravity location for the B-24 was an issue during the stages of development and production. I'm not aware with the conceptual stage details, but the aft fuselage section made the aircraft tail heavy, and resulted in additional stability issues. Development of the first generation tail turret had difficulties from the CG issue. I came across the information noted in AAF turret development literature and other published sources. Adding the nose turret during later models improved the balance of the airframe, with along the forward fuselage addition of the PB4Y-2.