The gas ejectors work as added thrust with the Spit and the Mustang until you hit around 400 knots then the pressure differential of the gas efflux and the slipstream over the the fuselage sets up a drag condition on the fuselage.

Shrug. Its a vacuum drag effect. In the motorjet it shows up INSIDE the motorjet around the piston engine! 

Herald

Thanks Herald. As I can recalled, only heavily modified Bearcat and MiG I-250 ever breached 400kt barrier of piston-driven fighters in level flight. While the Bearcat record is done in 1989 with probably new technology and specialized fuel, I-250 record was carried out with stripped down prototype.

As far as I can also recalled, the development of turbosupercharger on R-2800 and the steady increase of power from that power plant was quite smooth. What would you do if you are in charge of a fighter design team for a USAAF bomber escort in European theater?

P-47N as is.

Depends on the year and what I can license or steal from foreign technology..

If I start with the 1935 period I have four proven engine sources (Continental, Pratt and Whitney; Wright, and Allison) and SEVEN lines of airframe development. I have Curtis, Seversky, Grumman, Douglas, Boeing and the newcomers Lockheed and North American (North American Fokker. originally)

Based on what I've seen out of Curtis in the mid thirties, I fund one airframe line out of them, I fund one line out of Seversky, I fund one line out of Grumman. I find one out of Lockheed. The others have to take their chances and compete..

I ask for the following from the four engine manufacturers.

A corncob radial 1/1/1 or a 1 HP/1 cu. in./1 pound as measured in those days for an engine rated at MSL at 1500 HP takeoff and no less than 1000 HP cruise at 20,000 feet service ceiling. The whole engine with whatever boost addons NTE 1850 pounds total weight in a single pull package with a MTBT of not less than 100 hours.

An in-line conforms to the same specs.

That more or less could give me three row corncob Cyclones or Wasps, a possible P&W R-2060 Yellow Jacket and an Allison or a Teledyne Continental 0-1460 with GE turbo-chargers;. Assuming that any of it works, and that is a tall assumption, I now have my fighter and bomber engines. I hope I get at least two successful lines of them, because if I'm stuck with just an Americanized Merlin or an Allison to the design specs, I'm in trouble. Engine bottleneck.

For the sake of simplicity, let's suggest that a Pratt and Whitney develops the R-2060 Yellow Jacket and at the same time, produces a Wasp Junior corncob to specs.

I now have two radial engines, one that weighs 1800 pounds (the corncob)or thereabouts and one that weighs 2200 pounds.{the liquid cooled radial Yellow Jacket). Both engines are approximately 55 inches in diameter and both if they are to take a turbocharger will have to have to take twin turbochargers mounted at the engine sides and ram feed. My engine cowling becomes a pronounced oval. DRAG.

I am now forced to laminar flow the fuselage wing design. Expensive.

If the Allison is turbocharged to the design specs I get a 2200 pound engine and turbo-charger package. HMMMMM. This starts sounding like the P-38 twin engine fighter as I need a lot of fuel for a long range fighter.