posted 02-15- 08:12 PM               

I can get a passable high speed FM going in the P80b, which it looks like will have to evolve shortly into the F80c if we're going to do any Korea era modelling. Problem is, that prop thrust and jet thrust are quite different and I'm not sure is jet thrust is able to be properly modelled as OpenPlane stands right now, hope I'm wrong. Here's some info from the NASA history site that sheds some light on the subject.

"The performance characteristics of early jet fighters exhibited certain peculiarities as compared with those of contemporary propeller-driven aircraft equipped with reciprocating engines; these differences were related to the manner in which the thrust and power of turbojet engines vary with speed. A reciprocating engine generates the same amount of power at takeoff as at high speeds, whereas the turbojet at the same altitude has nearly the same thrust at both high and low speeds.
To give meaning to the different operating characteristics of the two types of engines, a simple example is offered as follows: A 10 000 pound propeller-driven fighter is powered by a 1600-horsepower engine and is capable of a maximum speed at sea level of 410 miles per hour. Near the beginning of the takeoff roll, the thrust at 25 miles per hour is estimated to be about 7500 pounds. Since the power is constant and proportional to the thrust times the velocity, the thrust at 410 miles per hour is about 1168 pounds. (Propeller efficiencies of 30 and 80 percent were assumed for the low-speed and high-speed conditions, respectively.) Accordingly, the thrust-to-weight ratio for the two conditions varies from 0.75 at 25 miles per hour to 0.12 at high speed. A jet fighter with the same 10000-pound gross weight and having an engine of 2500-pounds thrust has a takeoff thrust-to-weight ratio of 0.25 - and at 410 miles per hour still retains this thrust-to-weight ratio because of the nearly constant thrust characteristic of the engine. The power usefully employed in propelling the jet aircraft varies from 167 to 2740 horsepower as the speed increases from 25 to 410 miles per hour. These results are summarized in the following tabulation:
Characteristic Propeller Jet

P25 1600 167
P410 1600 2740
T25 7200 2500
T410 1168 2500
(T/W)25 0.75 0.25
(T/W)410 0.12 0.25
where the subscripts 25 and 410 refer to speeds of 25 and 410 miles per hour, respectively.
The results in the tabulation indicate the following two conclusions:
(1) The thrust-to-weight ratio T/W of the jet aircraft is small compared with that of its propeller-driven counterpart at low speeds. Thus, the acceleration of the jet aircraft on takeoff will be low; and the takeoff distance, correspondingly long.
(2) The maintenance of a nearly constant thrust-to-weight ratio through the speed range, however, gives the jet aircraft an important advantage at the high-speed end of the flight spectrum. Assuming that both hypothetical fighters considered have approximately the same drag area, the jet-powered machine would be expected to be much faster than the 410 miles per hour given for the propeller-driven aircraft. (Actually, level flight speeds as much as 100 miles per hour faster than those of contemporary propeller-driven fighters could be achieved by several of the early jet fighters.) "

posted 02-15- 11:06 PM               

For sure man. We NEED openplane code changed to include true Jet engines. No more of this piston engine with an invisible prop stuff.

For now i think the jets are mostly just going to be for fun and never really FM right until this is done.

posted 02-16- 12:13 AM               

Well don't give up man. Just don't exspect to get the perfect FM p80 right now.

posted 02-16- 01:26 AM               

Did that shooting star doc I sent you the link for help?

posted 02-17- 03:18 AM               

Yeah take some days off man before you burnout and then you will be gone for months.

posted 02-17- 08:17 PM               

SALUTE!