F-16 vs F/A-18

sprstdlyscottsmn · by **sprstdlyscottsmn** » 16 Feb 2018, 05:37

I don't recall anyone mentioning the Block 60, but if the question pertains to the "worst" Viper then I guess it is fair to bring it up. So we know the 60 has more thrust than the 52+, they should have similar weight. I see no reason for the 52+ to have better Sustained Turn than the 60.

tailgate · by **tailgate** » 16 Feb 2018, 15:15

sprstdlyscottsmn wrote:I don't recall anyone mentioning the Block 60, but if the question pertains to the "worst" Viper then I guess it is fair to bring it up. So we know the 60 has more thrust than the 52+, they should have similar weight. I see no reason for the 52+ to have better Sustained Turn than the 60.

Forgive me....it’s been awhile.....only having flown the 40 (-100) and 50 (-129), my comparison is only from what I know. The -129 gave you a little more kick in the mil thrust area, especially in the high ranges. I know the -129 had overall higher thrust but to me, AB felt the same ( maybe just a load out, profile thing....lol)

My question Sprtdly, looks like the CFT’s are mounted in a way to keep the CG as advertised (?). Is there much of a difference in flight performance between “full” and “ empty” CFT,s. I’m no aircraft engineer, I ask this because of the strake vortices production.....looks like those things will negate some lift regions....am I wrong?

Jimbo

sprstdlyscottsmn · by **sprstdlyscottsmn** » 16 Feb 2018, 16:45

Jimbo,

I'll check the HAF -1 when I get home. I'm pretty sure full CFTs are still CAT-I so any handling issues between empty and full are weight related. As to lift generation impact? I don't remember a striking difference between CFT vs non CFT lift generation, but it has been several years since I have last looked at that. Again, I look into it for you.

James

tailgate · by **tailgate** » 16 Feb 2018, 17:26

Thanks, I just remember that the blended wing body was considered a total lifting surface. Seems like any disturbance to that makeup would have effects. I even heard the "story" that went around that claimed some GD (back when it was GD !) engineer made the claim that even the canopy produced a little lift. Don't know if I believe that, but the jet did advance some pretty interesting concepts that made there way into other platforms

basher54321 · by **basher54321** » 16 Feb 2018, 18:26

Block 60 is coming to get ya!

hummingbird · by **hummingbird** » 17 Feb 2018, 01:02

tailgate wrote:Thanks, I just remember that the blended wing body was considered a total lifting surface. Seems like any disturbance to that makeup would have effects. I even heard the "story" that went around that claimed some GD (back when it was GD !) engineer made the claim that even the canopy produced a little lift. Don't know if I believe that, but the jet did advance some pretty interesting concepts that made there way into other platforms

Yes, roughly half of the lift generated comes from the body:

rheonomic · by **rheonomic** » 17 Feb 2018, 01:11

CFTs were designed to maintain the same handling qualities as without them and to minimize the performance impact.

sprstdlyscottsmn · by **sprstdlyscottsmn** » 17 Feb 2018, 06:15

22,000lb, seal level, DI=0

CFT
ITR peak 24.8@0.56M
STR peak 21.5@0.70M

Non CFT
ITR peak 24.8@0.54M
STR peak 21.4@0.70M

So it seems the CFTs had negligible effects of turning outside of added weight.

gc · by gc » 17 Feb 2018, 06:43

rheonomic wrote:CFTs were designed to maintain the same handling qualities as without them and to minimize the performance impact.

I always take that claim with a pinch of salt. Every Mudhen driver I have spoken to says that their airframe is significantly draggier compared to a clean F-15C and there is not chance they can turn and burn with a Eagle. Or maybe this problem is only specific to the F-15 CFT.

tailgate · by **tailgate** » 17 Feb 2018, 18:03

Thanks Sprty. Makes sense......darn those engineers, there purity smart

GC, greets, I have flown the Charlie version of the Eagle with CFT. I can’t say the performance suffered at all except for weight, but heck, even flying 3 bags, you get that. What most aviators do not like, is they are not jettison capable. In an IFE situation getting all the junk off and getting as light as possible could be key. It didn’t bother me with CFT except for that fact. A Strike can still turn and burn with the rest of em......just depends on the sit. Those -229 give quite a boost

zero-one · by **zero-one** » 18 Feb 2018, 08:41

Greetings Tailgate, without going into classified stuff, can you tell us what you do when you go up against Raptors in BFM?
I noticed that your Raptor tactics are very similar to your Eagle tactics (take the fight to the vertical). But what happens when they go up against each other. Do you out vertical an Eagle. Hard to believe anything can out Eagle an Eagle.

zero-one · by **zero-one** » 18 Feb 2018, 09:57

gc wrote:I always take that claim with a pinch of salt. Every Mudhen driver I have spoken to says that their airframe is significantly draggier compared to a clean F-15C and there is not chance they can turn and burn with a Eagle. Or maybe this problem is only specific to the F-15 CFT.

If I remember Sprts...graph correctly, the CFTs are not fully to blame for this. The Mudhen's stability is not the same as the Eagle's. The E models were more positively stable than the C Eagles which may have accounted for the decrease in traditional dogfighting performance.

sprstdlyscottsmn · by **sprstdlyscottsmn** » 18 Feb 2018, 14:56

That is incorrect. I was misreading CG location as Static Margin. It clearly states in a paragraph that the CFTs reduce stability and increase pitch sensitivity. Weight is the Mudhens enemy, and it has a lot of it.

tailgate · by **tailgate** » 18 Feb 2018, 17:23

Gotta remember that the Strike’s primary role is strike, with A/A being secondary, but that does not mean it isn’t capable. If a Strike “cleans” up before an engagement, you might be surprised at its capabilities. Just sayinn.........

quicksilver · by **quicksilver** » 18 Feb 2018, 20:24

tailgate wrote:Gotta remember that the Strike’s primary role is strike, with A/A being secondary...

^^
This.

What that means is that the pilot and WSO spend most of their somewhat limited (compared to e.g. the 1980s) training opportunities training for their primary role. Not as a rule, but typically, that manifests itself in dissimilar training -- i.e. they're not as proficient in the A-A stuff.