F-15a - building report

[deki]

Mr. Yoav, I appreciate your excellent work.

[papermate]

I'll be watching your masterpiece with admiration.

Papermate

[Loui]

i'll bookmark it. love it

[dhanners]

Originally Posted by elliott

Got a pic by any chance so I can better understand the reference to turkey feathers? I have an idea but am just wondering......

The so-called "turkey feathers" (more formally known as Divergent Nozzle External Segments) are the moveable panels surrounding the outside of the engine exhaust. Since about 1980, they've been absent from USAF F-15s and B-1Bs because they were considered more trouble than they were worth. They added weight and were very complex (translation: they required a lot of maintenance man-hours to keep them working) and so USAF just decided to get rid of them. There were vibration and harmonic issues leading to malfunctions and in some cases, "feathers" actually came off in flight.

[YOAVHOZMI]

Originally Posted by dhanners

The so-called "turkey feathers" (more formally known as Divergent Nozzle External Segments) are the moveable panels surrounding the outside of the engine exhaust. Since about 1980, they've been absent from USAF F-15s and B-1Bs because they were considered more trouble than they were worth. They added weight and were very complex (translation: they required a lot of maintenance man-hours to keep them working) and so USAF just decided to get rid of them. There were vibration and harmonic issues leading to malfunctions and in some cases, "feathers" actually came off in flight.

thanks for the useful information.

they are also removed in ISRAELI AIR FORCE, but as i said before my F-15 model represent a bird that still had those turkey feathers at that time.

by the way, why those problems that you mantioned happend with the F-15 nozzles and don't happend with the F-16 or other jets?

YOAV

[elliott]

Thank you for the clear explanation about turkey feathers. Turns out it wasn't what I thought it was after all.

[YOAVHOZMI]

Originally Posted by elliott

Thank you for the clear explanation about turkey feathers. Turns out it wasn't what I thought it was after all.

what you thought Elliot?

YOAV

[dhanners]

Originally Posted by YOAVHOZMI

thanks for the useful information.

they are also removed in ISRAELI AIR FORCE, but as i said before my F-15 model represent a bird that still had those turkey feathers at that time.

by the way, why those problems that you mantioned happend with the F-15 nozzles and don't happend with the F-16 or other jets?

YOAV

The nozzle segments on the F16 (and F/A-18) are of a simpler design and haven't presented as many mechanical problems. Plus, the segments are considered more integral to the F-16's aerodynamics. Taking them off the F-15 and B-1B created more drag, but not enough to write home about.

The problem with the feathers on the F-15 and B-1B was that you've got two engines right next to one another, and the segments that were usually failing were the ones on the inside, near the plane's centerline. It gets really hot between two big jet engines. The heat and vibration were causing the attachment and attenuation mechanisms to fail, so USAF decided that, all things considered, it was best just to get rid of them.

It was a lousy decision for aesthetics, but a great one for modelers who love to super-detail....

[YOAVHOZMI]

Originally Posted by dhanners

The nozzle segments on the F16 (and F/A-18) are of a simpler design and haven't presented as many mechanical problems. Plus, the segments are considered more integral to the F-16's aerodynamics. Taking them off the F-15 and B-1B created more drag, but not enough to write home about.

The problem with the feathers on the F-15 and B-1B was that you've got two engines right next to one another, and the segments that were usually failing were the ones on the inside, near the plane's centerline. It gets really hot between two big jet engines. The heat and vibration were causing the attachment and attenuation mechanisms to fail, so USAF decided that, all things considered, it was best just to get rid of them.

It was a lousy decision for aesthetics, but a great one for modelers who love to super-detail....

i am the opposite, i don't like hard life, therefore i decideed to build the F-15 with the regular nozzles.

YOAV

[YOAVHOZMI]

first, another part for the "cage frame"
this is a big flat cover that cover the "cagfe frame" and support the big parts above it creat good, strong and flat back.




because the parts of the main fuselage are so big, i could not put them in one file of A4 sheet, so i devided them to left and right.





the joining of left and right side of part no' 8.....the first part and the biggest part of the main fuselage.
the same process ia needed to the other part of the main fuselage.







now, we have to insert the big and wide part no' 8 from the aft of the frame to the front.










now joining the parts of the tail + the engines + the engines covers











YOAV