NationStates Jolt Archive

Was wondering if I could get some feedback, constructive critisism of this design.


http://img.photobucket.com/albums/v207/JC_Denton/NationStates/55444be8.jpg

http://img.photobucket.com/albums/v207/JC_Denton/NationStates/e218e22e.jpg


Wingspan: 12m
Length: 16.35m
Height: 3.9 metres
Empty weight: 24,000 pounds
Maximum Takeoff Weight: 54,000 pounds
Thrust: 120,000 lbst provided by 2 Colonial Aerospace F-106 Engines
Range: 1600 miles
Top Cruise Speed: Mach 2.75
Top Speed: Mach 4.15
Armarment: 4 wing hardpoints, 3 underfuselage hardpoints, lightweight wingtip mounting


In the year 2005, the Colonial Airforce was flying a variety of distinct aircraft that fit the medium fighter role. F-15 Eagles, EF-2000 Eurofighters and F-35 Joint Strike Fighters performed as the workhorses of the Airforce, while F-133 Valkyries (http://forums2.jolt.co.uk/showthread.php?t=362157&page=1) and F-106 Liberators (http://forums2.jolt.co.uk/showthread.php?p=7279039#post7279039) filled the more glamorous heavy fighter role.

The Colonial Aerospace Command, eager to simplify both the training and the variety of spare parts needed for operations, submitted a request for a new, medium strike-fighter that could replace the F-15s, EF-2000s and F-35s, while outperforming all of them.

The Colonial Aerospace Corporation was the first to respond, with the mating of 2 Colonial Aerospace F-106 Engines, providing a total of 60,000 pounds of thrust, onto the pre-existing X-32U prototype airframe. The X32U-F106E, later named the F-81 Peacemaker, won out in government trials against competing designs from the Pan Colonica Corporation and the Ocean Union, entered limited production in early 2008 and entered full production in late 2009.

The F-81 Peacemaker, while having no stealth or low radar visibility capabilities, does feature full 3-D thrust vectoring engines, that in conjunction with the canards, allow for a high degree of manuverability. As well, the F-81 Peacemaker is fully capable of V/STOL operations.

Looks good to me; I'd probably purchase some once they're available.

Well, if no one has any complaints, I'll end up selling them.

There is a problem, your pounds of thrust is below the total weight of your aircraft. That's not enough to make your aircraft get off the ground. Also, at the posted speed it would not have any manueverability.

Well, there are a few problems I see. First and foremost, the empty weight is too low for the maximum takeoff weight provided. The empty weight is rarely more than 45-50% of the max takeoff. With it being only about 32% in this unit, it's a bit of a stretch.
The speed is also too high. To get that kind of speed, you'd need massive engines. The kind that would preclude any internal space and provide serious limits on external armament. Realistically, with genuine supercruise, you would have to cut the speed in half to give it an acceptable payload. When you drop the speed, you could also up the range to 2000 miles or so. 1250 is actually rather short for a modern combat aircraft.

There is a problem, your pounds of thrust is below the total weight of your aircraft. That's not enough to make your aircraft get off the ground. Also, at the posted speed it would not have any manueverability.

I don't think that actual thrust has to be more than the the maximum takeoff weight. Have a look here: http://www.globalsecurity.org/military/systems/aircraft/f-15-specs.htm

The F-15 Eagle is powered by two Pratt & Whitney F100-PW-100 turbofan engines with afterburners, each rated at 25,000 pounds engine ( 11,250 kilograms).

The maximum takeoff weight of the F-15 is 68,000 pounds (30,600 kilograms).

25,000 x 2 = 50,000
50,000 - 68,000 = -18,000 pounds

While the thrust for the F-15 is less than the maximum takeoff weight, the lift provided by the airframe is enough to compensate.

As for manuverability - well, that might be more of a valid point. However, the canards, and the 3-D thrust vectoring that you've reminded me to put in should help with that.

There is a problem, your pounds of thrust is below the total weight of your aircraft. That's not enough to make your aircraft get off the ground. Also, at the posted speed it would not have any manueverability.
Few aircraft have thrust that equals their maximum takeoff weight. Consider that an F-15E has a max takeoff of 81,000 lbs, but a total thrust of only 58,000 lbs on full burn. It doesn't need that much thrust to get off the ground.

Well, there are a few problems I see. First and foremost, the empty weight is too low for the maximum takeoff weight provided. The empty weight is rarely more than 45-50% of the max takeoff. With it being only about 32% in this unit, it's a bit of a stretch.
The speed is also too high. To get that kind of speed, you'd need massive engines. The kind that would preclude any internal space and provide serious limits on external armament. Realistically, with genuine supercruise, you would have to cut the speed in half to give it an acceptable payload. When you drop the speed, you could also up the range to 2000 miles or so. 1250 is actually rather short for a modern combat aircraft.

Thank you for the feedback. I've lowered the Maximum Takeoff Weight to 42,000 pounds, increased the range to 1600 miles, lowered the amount of internal hardpoints, and lowered the speeds a little bit.

I'm with you on the engines though. Basically, what I've done is taken a pair of really huge engines designed for a heavy fighter and stuck them into a medium fighter. That's why I wanted the range to be a bit low - to reflect that the internal fuel tanks were a bit small because of the large engines.

SS: not even the eurofighter has a 1:1 ratio (although the final tranche 3 version might if the EJXX engine actually gets developed)

OOC: Very nice plane, looks good and seems to have a nice payload but the thing that enticed me is the lack of "OMG! MACH 6-8 SPEEEEEEEEED" so I must commend you on resisting the urge to wank your planes.

Nice job.

How is mach 4.1 supercruise possible?

(not that I really know anything about planes... but it just seems that tech in general in NS has gone to RL+1 being the minimum acceptable to remain competitive)

Mach 4 is the maximum speed and Mach 2.8 is listed as its supercruiser speed. I want to know how mach 4 is possible without a psuedo-scramjet or em pulse-detonation. Conventional afterburners are extremely inefficient but you're stating a near doubling of speed.

You would have to offer some sort of new technological developement that explains this - please refrain from the "I seen it done on the x-files" excuse.

And it not having stealth capabilities heading for production in 2009 is political and financial suicide.

OOC: Looks nice, just the speed looks off... Mach 4.1? Hell, the fighter I use has 98,000+ lbs thrust from two engines (PDET-hybrids), but even it can only get Mach 3.55 max...

Also, your supercruise speed is a bit high.

Thank you for the feedback. I've lowered the Maximum Takeoff Weight to 42,000 pounds, increased the range to 1600 miles, lowered the amount of internal hardpoints, and lowered the speeds a little bit.

I'm with you on the engines though. Basically, what I've done is taken a pair of really huge engines designed for a heavy fighter and stuck them into a medium fighter. That's why I wanted the range to be a bit low - to reflect that the internal fuel tanks were a bit small because of the large engines.
You can up the maximum weight to 50-60,000 lbs at least. You have to have some weight for fuel and payload, or you can't possibly claim this as a successor to multirole aircraft like the EFA 2000 and F-35.

Again, I told you to cut the speeds in half. I could see for this is maybe a Mach 2.5 top speed with something like a mach 1.2 supercruise (the higher the top speed, the lower, proportionally, the cruising speed - that's how the different types of turbofans work). Also, so long as you have an internal weapons bay, you will have to restrict the engines, so a Mach 2.5 top speed does require completely removing the weapons bay.

Well, if this is an air superiority aircraft, an internal weapons bay may as well be more than possible (I use it on my F-125), considering that the XF-108 design did include an internal weapons bay. External weapon carriage at high Mach 2.5+ speeds may actually be counterproductive, considering the drag and other limitations created by externally-mounted weapons, and this is one of the reason why many of the times the MiG-25 reached the Mach 2.8 maximum allowed speed without any weapons.

However, since this is an actual multirole aircraft, this wouldn't be necessary unless the aircraft itself is a stealthy design (in which speed must be sacrificed if you want stealth - keep in mind that if you want to go for high speeds, you'll need some larger engines which requires something otehr than fixed intakes present in stealthy designs, not mentioning that stealthy designs typically hinders the possibility of better aerodynamics for M2+ speed). If the intake is mounted on the bottom of the fuselage like the Eurofighter, I'd suggest a "S-shaped" scheme (basically the intake is curved into a S shape) for stealthiness.

The cannon could also be changed to a 27mm, which will be more effective although you'll typically have less rounds, and don't forget that if you are deciding to have all the weapons mounted externally, you can have more hardpoints too.

V/STOL I'm not sure since it'll typically require specialized propulsion designs (such as the liftfan on the F-35 or the liftjet of the Yak-141), and keep in mind that 3D thrust vectoring does not allow V/STOL, but aids in V/STOL operations and improves upon climb performance. So my suggestion is to scrap VTOL/STOL capability and go for a conventional design instead where you would also have more room for payload.

Okay, I've made a few more alterations. Thanks to everyone for thier input, it's really helpful.

Changes:
- Maximum takeoff weight increased to 54,000 pounds
- Introduction of a standard cruising speed in the performance specs: Mach 1.75
- Upping of thrust to 100,000 pounds (I know that sounds odd, I'll address it)
- Removal of 20mm canon to reflect the large size of the engines, lack of interior room in the airframe
- Removal of internal weapons bay, replacement of hardpoints onto underside of fuselage


I guess the first thing I should explain is the 100,000 pounds of thrust engines. Well, IC, the Colonial Aerospace F-106 Engines were the result of a massive 6 year, 1.3 trillion dollar development program. The cost of development, for the record, is 4 times of the entire US defense budget in 2002 (http://en.wikipedia.org/wiki/Defense_budget). The F-106 Engines were first put to use in the F-106 Liberator, which is a 55,000 pound plane with a maximum speed of Mach 3.85.

I'm keeping the V/STOL capability, admittedly, mainly because of the fact that there's a massive lift fan visible in the first picture just behind the cockpit, and VTOL is the only purpose that it could serve.

I'm also not incorporating any stealth features into the plane because I want it to be as fast as possible - the design compromises needed to make it stealthy would lower the speeds achievable. I want the F-81 Peacemaker to be capable of intercepting the Decisive Action / Communist Missisipi produced MiG-41 Good Ole Boy, which can achieve speeds of Mach 4.09 (http://forums2.jolt.co.uk/showthread.php?t=359667).

Nearly every aspect of the aircraft has suffered because of the requirement that it be able to intercept a DA MiG-41. The range is lower then that of an F/A-18 Hornet, a plane often accused of having a low range, there are no stealth features, there is no gun, and there is no internal weapons bay. The weapons that previously were carried in the bay have been moved to the underside of the fuselage.

Does this sound better?

I'm also not incorporating any stealth features into the plane because I want it to be as fast as possible - the design compromises needed to make it stealthy would lower the speeds achievable. I want the F-81 Peacemaker to be capable of intercepting the Decisive Action / Communist Missisipi produced MiG-41 Good Ole Boy, which can achieve speeds of Mach 4.09 (http://forums2.jolt.co.uk/showthread.php?t=359667).


OOC: Virtually everyone ignored DA's godmodded stats. He proclaimed to be able to hit Mach 4 with less than half the total thrust of a F-15E Strike Eagle, had over 15km range for his tanks, etc...

Here is a question, how is that thing gonna fly at top speed without having those weird shaped wings torn off?

OOC: Virtually everyone ignored DA's godmodded stats. He proclaimed to be able to hit Mach 4 with less than half the total thrust of a F-15E Strike Eagle, had over 15km range for his tanks, etc...

Hmm... I don't want to ignore DA though. Well, if he's brought back from deletion anyways. DA was such a good villain - racist, facist, violent: DA was the IC 'Evil Empire' to my IC free paradise. A villain that you had to love to hate.

Hmm... I don't want to ignore DA though. Well, if he's brought back from deletion anyways. DA was such a good villain - racist, facist, violent: DA was the IC 'Evil Empire' to my IC free paradise. A villain that you had to love to hate.

Hey, I'm an IC evil empire, although my own brand of nastiness is a bit more subtle than his.

Hey, I'm an IC evil empire, although my own brand of nastiness is a bit more subtle than his.

That's the thing. We've got plenty of 'evil' nations on NS, but DA was always the worst in my mind. Public lynchings, widespread sexism, rampant aggression, slave taking, genocide - DA didn't care about world opinion or moral condemnation. DA was evil to the core, had huge, well outfitted, nearly over the top legions of doom (TM), and was constantly in a state of either war, oppressing people conquered in war, or preparing for war. DA was Darth Vader to my Han Solo, the Cardassian Union to my United Federation of Planets. Decisive Action was the opposite of the Democratic Colonies in nearly every ideological way.

DA just seemed to be a collection of every single thing that I opposed or hated wrapped up into one scary little package, and was my favourite 'evil' NS empire for that reason.

Okay, I've made a few more alterations. Thanks to everyone for thier input, it's really helpful.

Changes:
- Maximum takeoff weight increased to 54,000 pounds
- Introduction of a standard cruising speed in the performance specs: Mach 1.75
- Upping of thrust to 100,000 pounds (I know that sounds odd, I'll address it)
- Removal of 20mm canon to reflect the large size of the engines, lack of interior room in the airframe
- Removal of internal weapons bay, replacement of hardpoints onto underside of fuselage


I guess the first thing I should explain is the 100,000 pounds of thrust engines. Well, IC, the Colonial Aerospace F-106 Engines were the result of a massive 6 year, 1.3 trillion dollar development program. The cost of development, for the record, is 4 times of the entire US defense budget in 2002 (http://en.wikipedia.org/wiki/Defense_budget). The F-106 Engines were first put to use in the F-106 Liberator, which is a 55,000 pound plane with a maximum speed of Mach 3.85.

I'm keeping the V/STOL capability, admittedly, mainly because of the fact that there's a massive lift fan visible in the first picture just behind the cockpit, and VTOL is the only purpose that it could serve.

I'm also not incorporating any stealth features into the plane because I want it to be as fast as possible - the design compromises needed to make it stealthy would lower the speeds achievable. I want the F-81 Peacemaker to be capable of intercepting the Decisive Action / Communist Missisipi produced MiG-41 Good Ole Boy, which can achieve speeds of Mach 4.09 (http://forums2.jolt.co.uk/showthread.php?t=359667).

Nearly every aspect of the aircraft has suffered because of the requirement that it be able to intercept a DA MiG-41. The range is lower then that of an F/A-18 Hornet, a plane often accused of having a low range, there are no stealth features, there is no gun, and there is no internal weapons bay. The weapons that previously were carried in the bay have been moved to the underside of the fuselage.

Does this sound better?


The thing is...

DA has been deleted, and his puppets as well.

So there's no DA Old Boys jets to fight aganist.

The thing is...

DA has been deleted, and his puppets as well.

So there's no DA Old Boys jets to fight aganist.

He exported the things, they were sold at his storefront. I would imagine that plenty of his allies like Kahta have them. Besides, last I heard, he was trying to get himself brought back.

IC though, even if DA just suddenly imploded on itself in a non-sensical cartoon fashion, the F-81 Peacemaker would still exist. Just because the threat no longer exists, dosen't mean that the military equipment being developed to fight that threat aren't continued. The F-22 Raptor is probably the best example of this - designed to fight the Soviet Union in a conflict between the forces of NATO and the Warsaw Pact. Obviously, the Soviet Union is no longer around, but F-22 Raptors are still planned to go into production and enter active service.

He exported the things, they were sold at his storefront. I would imagine that plenty of his allies like Kahta have them. Besides, last I heard, he was trying to get himself brought back.

IC though, even if DA just suddenly imploded on itself in a non-sensical cartoon fashion, the F-81 Peacemaker would still exist. Just because the threat no longer exists, dosen't mean that the military equipment being developed to fight that threat aren't continued. The F-22 Raptor is probably the best example of this - designed to fight the Soviet Union in a conflict between the forces of NATO and the Warsaw Pact. Obviously, the Soviet Union is no longer around, but F-22 Raptors are still planned to go into production and enter active service.

Thanks for clearing that up. I was just not sure what happens to exclusive weapons programs aganist "enemies that cease to exist".

Sorry if I stepped on your toes. The jet looks good by the way. :)

Thanks for clearing that up. I was just not sure what happens to exclusive weapons programs aganist "enemies that cease to exist".

Sorry if I stepped on your toes. The jet looks good by the way. :)

Thank you. And there's no need to apologize - the thread is for other RPers to point out any possible flaws or problems with the plane. The design has already undergone quite a few changes because of things people have posted, and some of the changes have been pretty big. I really appriciate the fact that people are taking the time to post in here and help with the plane. :)

Okay, so, no further comments? No complaints, I could roll this fighter out tommorow and export a few to PIcaRDMPCia?

I've increased the thrust to 120,000 pounds, and have increased the speeds to the following:

Top Cruise Speed: Mach 2.75
Top Speed: Mach 4.15

I believe that if IC I spent 1.3 trillion dollars developing the engines, they can surely deliver that much thrust. For that amount, I could have payed for the development programs of the F-22 Raptor, F-35 JSF and EF-2000 Eurofighter a dozen times over each, and still have had having enough to pay for the International Space Station ten times.

Engines that powerful on a fighter lighter than a Super Hornet would enable Mach 4.15 flight, wouldn't they? Even if all of the other performance areas suffer?

Woohoo. I like a lot. Especially the fact that a nuclear ICBM shares the same name.

:D

Woohoo. I like a lot. Especially the fact that a nuclear ICBM shares the same name.

:D

No, that's the Peacekeeper (http://www.geocities.com/peacekeeper_icbm/). This is the Peacemaker - I think that tells potential importers something about the role of the aircraft.

:)

So this preceedes a vist from the keeper, eh?

;)