super charged vrs turbo charged

[erj-145mech]

The exhaust stacks on the DC-6 point straight back, ostensibley to take advantage of exhaust thrust, according to one of my Douglas manuals. I don't have the book in front of me, but is seems like I recall they were claiming to recover several hundred horspower that way.

The exhaust stack/s on B-17's, B-25's, F6F's, F4U's, AT-6's, BT-13's and my Skymaster all point aft, and they don't realize any "thrust" from the exhaust. They point aft to help in scavenge the exhaust gases from the pipe openings, reducing the back pressure on the engine.

 

[bocefus]

"In line with the subject matter, if you ever fly, especially a 400 Series Cessna that still has Turbo Charged on the side or on the cowls, watch the lineman very closely when refueling."

Can't happen if the AD's are complied with.

 

[gern_blanston]

The exhaust stack/s on B-17's, B-25's, F6F's, F4U's, AT-6's, BT-13's and my Skymaster all point aft, and they don't realize any "thrust" from the exhaust. They point aft to help in scavenge the exhaust gases from the pipe openings, reducing the back pressure on the engine.

Hawker's used to claim that a good bit of thrust was realized from the exhaust stacks on the Merlin.

 

[A Squared]

I'd love to see that part of the book. I remain fairly skeptical about that particular claim.

OK, I dug out the book. It's a study guide Douglas wrote for airline flight crews. It doesn't make a specific claim about the amount of power or thrust recovered. (I guess I remembered that detail incorrectly) it says: "The DC-6A uses a jet stack type exhaust arrangement that utilizes the exhaust velocity to augment the propulsive thrust"

 

[gern_blanston]

Found these 2 quotes googling 'Spitfire exhaust thrust'

"The '109 used exhaust thrust to gain more speed. Daimler-Benz charts show 120PS of exhaust power at 600 km/h at 4.5 km for the 109 Emil's engine. Another German paper shows 200-300hp produced by thrust alone at 600km/h at 10000m."

"In 1943 some spitfire Vbs also had their 'fishtail' type exhaust stubs replaced with multi-ejector stacks, the better aerodynamics and thrust generated by the new exhausts adding a further 5 mph down low."