Forum: Off-topic

Hoodeehoo there neighbors,

To start with, a special hello to all the old time drivers, mechanics, and developers out there, insane respect for you guys (Gums I'm talking to you). Like I said in my "introduce yourself" post, I'm no true expert, I just love this stuff. That said, I have an idea that might be fun for some of us to play around with: designing a hypothetical aircraft for a hypothetical requirement, just to see what we come up with.

Now let's stop for a moment so I can clear up what this is, and just as importantly, what it isn't. This is not a serious discussion of policy, politics, procurement hell, or aircraft bashing. This is not going to be 100% in the real world, where F-16s are the export kings and everyone else has MiGs or Mirages, and that's almost all. Most importantly, this is not a thread where I want to hear "that's stupid" or "you're not living in the real world" or "what a waste of time." This is a place to toy around with new ideas, be unrestrained by what's already be done, and come up with something interesting, all while having good-hearted fun in the process, and contributing whatever knowledge or hare-brained thoughts you might have to the design! Not all will be adopted, and some may be modified. The only real limit is that the resulting plane needs to be able to fulfill a challenging set of requirements and be something that would have the benefits and capabilities needed to make it desirable to its target market.

So if anyone here is interested in playing along, come on! I think it could be a great start to some really interesting discussions, and for amateurs like me it could be pretty edumacational, especially as we get into the fine details.

Here's the basic requirements (subject to change and further clarification based on your input):

-Maintainability:
-Minimal need for ladders or workstands
-Minimal specialized equipment
-Minimum component change time and effort
-Maximum MTBF for all components
-Maximum reduction of moving parts and components with high failure rates
-Engine optimized for ease of maintenance and replacement, including inspection
via borescope without removal
-Deployability:
-Rough field capability
-No groundhogs
-Ability to conduct sustained operations from austere locations (Think dispersing
aircraft among multiple FARPS set up on strips of highway and rough fields, using
only what can be hauled in by Chinook, then redeploying the aircraft from one
strip to the next to keep the enemy guessing)
-Responsiveness:
-Minimum alert time
-Self-start ability
-User friendliness
-Minimum cockpit workload; highly intuitive controls
-Extensive safety aids (IFCS with limiters, EVS, advanced ejection system, fire
detection/suppression system, etc.)
-Performance:
-Agility second only to vectored-thrust aircraft
-Thrust to weight ratio equal to or better than 1:1
-Rapid climb rate and acceleration/deceleration
-Ability to handle high sustained G loadings
-No handling vices
-Sufficient range and endurance for expected missions; IFR capability essential
-Avionics:
-Advanced capability radar (preferably AESA) and EO/IR sensors
-Internal FLIR/designator preferred, pod-based solution acceptable; IRST and TISEO desirable
-NVG-compatible partial or full class cockpit with helmet-mounted display
-Flexible RF COM/NAV/datalink capabilities
-Embedded GPS/INS navigation
-Modular mission computer with mission recording
-High-speed data bus (i.e., MIL-STD-1773 or IEEE 1394)
-Survivability:
-Integrated threat warning system and EW system; internal preferred, pod-mounted ECM may be acceptable
-Advanced countermeasures dispensers
-RCS reduction features (as found on F/A-18E/F, E/A-18G)

-Lethality:
-Compatibility with diverse range of guided and unguided A-G ordnance, close
range and BVR AAMs, and other stores
-Highly-capable cannon solution (i.e., M61A2/GAU-22/Nexter 30M 791/Mauser BK
27, etc.)

So I know that's really asking a lot. I'm not looking for a rough-field F-22. This is more like the F-20 Tigershark: simple, reliable, cheap and easy to use, a real winner for the budget-conscious allied nation. But we're going to relax the "cheap" requirement a bit so that we can go slightly buck wild here. Stay within the realm of feasibility to some rational extent, but don't be afraid to go out on a limb and get really ambitious with the design. It may be easier for this first project if we start with an existing airframe and go from there. I think the F-20 might be a good starting point, since it's already so well optimized to meet many of these objectives. Of course, if anyone prefers something else as the basis, please speak up.

If I may, I'd like to suggest that we start by firming up the requirements. Then we can look at what design features and systems we'd like to see, a kind of Christmas wish list if you will.

For those of you who haven't fallen asleep yet and are interested, I hope to hear from you and see what you've got! I really hope to hear from some of the senior guys, since your knowledge will be a tremendous help! Again, just for fun, we're not building mockups or anything here (unless the modeling guys want to get in on it, in that case be my guest)! Smile

Toodles,
John

F-16.net Sponsor

Last edited by 1st503rdsgt on Oct 15, 2012 - 03:16 PM; edited 1 time in total

Conceptually, the F-20 is flying all over the world today. Off the top of my head: F-CK-1, Gripen, FA-50, Tejas, and even the JF-17 are all rather similar to the F-20 in terms of their design goals. Three of them even use the same engine.

The F-20's real curse was being American. No one really wants to buy a consulation offering that isn't being picked up by the USAF, and the USAF would prefer that everyone buy what it's buying to keep its own costs down.

But let's say a US company wants to enter this small, saturated market. The starting point should probably be a single F414 EPE engine.

Hi 1st503rdsgt, thanks for the reply!

I agree through and through with your analysis of some of the reasons for the F-20's market failure. To be honest I had completely forgotten about the FA-50.

As for the engine I was also looking at the F414 EPE. Looking at the weights of all these different aircraft, it's all in the same ballpark, and most of them use variants of the F404 as you said, so the 414 should give a real boost. The F100 and F110 would as well, but with significantly higher weight (far from desirable).

Looking at the maintenance side of things, I saw this: http://www.f20a.com/f20f404.htm
It seems that the F404-GE-100 featured a modular construction to speed up turnaround times. I'm wondering if it might be a good idea to pursue this with the F414 (unless of course it already comes with this feature?). And AFAIK, the old F-5's had their J85's mounted on overhead rails to make it easy to slide them out once they'd been disconnected (supposedly engine change time was only 20 minutes?!). Might be a good idea here too.

Fighter design is all about the compromise, and maintenance-friendly features tend to add weight. For our theoretical export fighter, there are many things more important than a quick engine change.

Good point, what might you suggest?

What precludes Yak-130, MB-346, Hawk 200, L-159A, JJ-9, and JF-17 from this role?

Absolutely nothing. But the idea here is to come up with a new plane of our own Crazy Pilot

Any ideas madrat?

This is what more or less amounts to a MTR, aka Monthly Topic Rotation, on F-16.net

Search for Today, AREA 88 recruits you to fly the <insert> http://f-16.net/f-16_forum_viewtopic-t- ... -f20a.html

Other posts I've had:

madrat wrote:

What if Northrop had offered an F-20 Lite option, say substituting the tfe1042-7? Jump all over the F-19 designation that was conveniently skipped. (Giving it a magical trifecta of numbering designations; three in a row.) Use the F/A in the designation to denote its multipurpose roles. Give it a catchy name based on a predator or ancient warrior. Partnered up with Grumman a few years earlier, then offering relative versions from each like how automobile makers varied similar models using the same wheelbase in that time period. (i.e. Grumman F/A-19 Tiger III versus Northrop F/A-19 Ninja) Offer a proper gatling gun; maybe a three barrel 20mm variant based on the M61. Offer a refueling probe. Pushed a little harder on the affordability front with regards for the export crowd. Perhaps this lesser option would have more up the alley of countries using the F-5 already. I like the F-20A, but it may have been too much to swallow coming out of the gates for its target audience.

madrat wrote:

If they go the T-50 airframe route I hope they downgrade the engine requirement to an F125. The F404 and F414 are too much engine for the role.

Here is another related topic:

http://f-16.net/f-16_forum_viewtopic-t- ... r-asc.html

http://f-16.net/f-16_forum_viewtopic-t- ... t-t50.html

http://f-16.net/f-16_forum_viewtopic-t- ... -f414.html

http://f-16.net/f-16_forum_viewtopic-t- ... r-asc.html

http://f-16.net/f-16_forum_viewtopic-t- ... r-asc.html

http://f-16.net/f-16_forum_viewtopic-t- ... r-asc.html

Much appreciated, madrat. Your AREA 88 topic was especially interesting (I might just have to come up with something for it, even if it's 2 years late!). And maybe this is an MTR, but hopefully it'll turn out to be a bit more than that. The idea is roughly similar to yours, but without a points system, no restrictions on the vintage of tech involved, and we're probably going to end up with a clean-sheet design (might consider adapting an existing airframe such as F-20/Gripen/ALCA, but we'll see). The key will be how to keep people's interest piqued.

On the subject of technical stuff, I'd like to hang onto the idea of the quick engine change, but lower the priority level in order to focus on performance. With the added life and reduced maintenance requirements of the EPE engine over the -400, it might be better to focus on how to mitigate one of the biggest contributors to unscheduled engine maintenance needs: FOD. This might be possible with a far lower weight penalty. At the same time, we could look at how to get the best performance out of the engine.

So questions/ideas:
-What type of inlet? Diverterless supersonic? Wing root/underwing/overwing/dorsal/ventral?

-The Mig-29 has a set of inlet doors to protect the engines from FOD, with a couple of auxiliary inlets in the
upper intake trunks. This should be an effective solution, as long as they can be made light enough and with a
minimum of moving parts. Diverterless intakes are already lighter and simpler than traditional units with
diverter plates, so it would seem that the weight penalty should be minimal. Using electrical actuators for the
inlet doors should keep moving parts to a minimum.

-How about the exhaust? Something along the lines of the experimental LOAN nozzle tested on the F-16? I'm
assuming any kind of thrust vectoring is out of the question due to cost/weight/complexity issues, and any kind
of fluidic TVC is still a long way off.

-As for GE's claims about the EPE engine, they say that it will offer up to a 20% increase in thrust over the
F414-GE-400, or a threefold increase in component life at the -400's thrust level. -400 produces up to 22,000
lbf so that would be roughly 26,400 lbf for EPE. For reference, the JAS 39C/D Gripen uses an RM 12 (F404)
turbofan with 18,100 lbf afterburning, and has MTOW of 31,000 lb. The T-50 uses an F404 rated at 17,700 lbf
afterburning and has MTOW of 29,700 lb. While this plane of ours might end up being slightly heavier, I'm
wondering if we might not need the full 26,400 lbf (at least not right away)? Maybe somewhere between that
and the 22,000 so there's still some reliability gain?

The Mig-29's anti-FOD system was problematic and heavy; the latest version (Mig-35) doesn't have it at all. As for LOAN, I thought we were trying to keep costs down, so let's forget about that or TVC. In fact, it's probably best to just forget about LO altogether and rely on our fighter's small overall size to give it some advantage.

Fair enough, no FOD doors, LO, or TVC. So then we just need to think about an inlet to maximize airflow with minimal weight and complexity, and an exhaust to efficiently focus thrust.

In other words, we basically end up with a Gripen every time.

J85 was a solid, low cost powerplant that allowed field servicing. A-37 is a good basis for LWF subsonic attack plane and F-5E/F for LWF supersonic fighter. There are several engines in the 6-8K pound static thrust range suitable for today's equivalents. Electronics in fighters are falling behind consumer electronics by almost two decades. A lot of current bleeding edge fighter hardware is utterly dinosaur compared to the efforts put into cellphones. Your new planes can tote 70mm smart rockets in 19-shot cannisters and do ungodly amounts of damage compared to five decades back.

Well 503, maybe. We are still just talking about propulsion, and haven't looked at the various other pieces of the puzzle in any great detail yet. What would be your idea of the ideal for this piece? Madrat, I like your comment about the J85s. Unfortunately I think we'll need something in a higher thrust range if we're to achieve a good enough thrust-to-weight ratio for supersonic flight and dogfighting (Lots more weight to tote around these days). That said, I am a big fan of LOGiR, APKWS, and CRV7-PG. As you pointed out, that's a lotta hurt. Avionics are an interesting if convoluted subject, and absolutely it's interesting how defense electronics today always remind me of 1980s cell phones. I'm curious as to whether you two or anyone else out there might be an avionics guru willing to help out?

Forum: Off-topic

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