tom_19d
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Posts posted by tom_19d
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I misunderstood your post. I took it to mean you assigned the waypoint IN the ME. My apologies...
No worries at all. I was just trying to do everything I could (direct entry of a perfect grid and elevation into the CDU, no TGP, etc) to take away every variable of employment and putting all the performance on the bomb itself...
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Did you try creating a mission point via the CDU using that 10-digit grid as if passed by a JTAC or FAC(A)?
I’m not sure what you are asking here, as I only created the target waypoint via the CDU. Setup cockpit in the ME puts you in engine so you can start the mission with the avionics programmed, I used zero ME generated waypoints in the trials.
I’m curious what MGRS coordinates the TGP would yield in Point Track on that tank?
TGP 3.9 miles with a point track, Laser on, GG 15857 10366, it is within a meter both directions.
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Before I begin, I would like to note I performed these tests before I saw this thread was marked [Reported], but regardless I thought they might be of interest.
I have been part of a number of “GBU38 broken?” type threads and what has always frustrated me is there has never been a defined standard of performance we seem to be going for as a community. What I mean is that someone will pose an often anecdotal type question about GBU38 performance, some people will second it, and others will have some variety of “working fine here,” and a discussion over proper switchology will ensue. What never seems to be addressed is a quantifiable measure of what is acceptable and what isn’t.
I wanted to address this issue with at least an attempt to create a repeatable, measurable test that would remove as many variables as possible so we could look simply at the 38’s performance. The standard of performance I decided on was a K-Kill on a static tank. I’m sure some of the scripting wizards here would use MOOSE to determine CEP, or something to that effect; I would find that fascinating but I don’t have the time to sort that out, and to be honest I think complete destruction of a static tank could be the ultimate “gold standard” of GBU38 performance for our needs.
CONDITIONS
That said, I placed a static T72 at 37T GG 15858 10365. This point is the beginning of the first runway stripe on the arrival end of Rwy 13 at Batumi. The tank was aligned longitudinally with the centerline.
Meteorological conditions were ISA, winds calm.
I then placed an A10 at 8000 feet MSL 5 miles northwest of the tank, aligned down runway 13. It was armed with GBU38s on stations 3 and 9, 4000 lb fuel, full CM gun. Using the mission editor’s “setup cockpit” function, I created a waypoint in the A10 at 37T GG 15858 10365, 33 feet MSL, named it “TANK”, and saved the setup. (Interestingly enough, every time I launched the mission this waypoint would show up as GG 15857 10364. I tried numerous times to place a new aircraft and “setup cockpit” again, double checking my entry, but for some reason when I would launch the mission the waypoint was always 1 meter west and 1 meter south of where it was placed. This means the steerpoint was 1.4 meters from the center of the tank, still under its footprint, but I thought it worth mentioning in the spirit of complete disclosure).
Next, I started this mission 20 times. I performed the following steps each time…
-Select FUNC and MSN on the UFC to give me access to the TANK waypoint
-DMS FWD (short) to select the TANK waypoint (STRP is already SPI)
-DMS RIGHT (short) to select GBU38 CCRP
-Fly to the following target parameters and release a single GBU38: 275 KIAS, 8000 MSL, 2.1 NM to steerpoint (~1/2 through the GBU38 CCRP engagement envelope), 1.0 G.
-Let the bomb land, save the track, and repeat.
After 20 iterations I went through the tracks and documented my actual flight parameters at release and the result against the tank. I would also point out I took no “alibi” passes or any such thing. Once I resigned myself to not being able to resolve the 1.4 meter waypoint discrepancy discussed above I recorded tracks of 20 consecutive passes regardless of result.
RESULTS
Drop parameters were held as consistent as possible. Across the 20 drops, standard deviation from the target airspeed of 275 KIAS was 1.47, with an extreme maximum of 279 and minimum of 274. Standard deviation from 8000 feet MSL was 6.54 feet, with all drops occurring between 8010 and 1790 MSL. Distance from the 2.1 NM release target had a standard deviation of .03 NM and a range of 2.2 to 2.0. G was kept at .9 on 5 of the runs, with the remaining 15 at 1.0 G.
In every drop the tank was damaged to some extent. (Hopefully someday M-Kills and F-Kills will be modeled in DCS). 75% of the drops resulted in a catastrophic kill of the tank.
CONCLUSION
This trial presented the A10C and GBU38 with conditions for weapons release as close to ideal as possible; no enemy threat, no wind, clear skies, and most importantly a SPI set perfectly at the target elevation and within 1.4 meters of its center. All that said, 25% of the time the target was not destroyed in one shot. Said another way, an A10C carrying 4 JDAMs can reasonably expect one of them to miss under near perfect conditions, to say nothing of the errors that can creep in when trying to designate targets with the targeting pod, let alone considerations for enemy fire or adverse weather. Under the current state of the game, this tells me that when a tank positively, absolutely has to go down in one pass, I will be leaning on the Maverick and LGBs.
I will post an example track of my trials, #16 (a miss) and a PDF of my recorded data from the entire series. I welcome any questions or critique of my method.
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CRJ 700 does not have an inertial navigation system? Are we talking about the regional jet built by Bombardier and which has a Collins Aerospace (former RockwellCollins) provided Pro-Line-4 cockpit suite and the FMS4200? Because that has two redundant INS...
Anyway, this gets pretty much OT here...
-They might have an IRS (primarily an AHRS stand-in), not the same thing as you have been talking about, and even that is not fleetwide equipage. You are overestimating the aircraft that have an INS onboard. Maybe the issue here is nothing more than differences in specificity of language being used.
Agreed on the OT, like I said previously, I think the OP raises a valid concern and hopefully it is addressed going forward.
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Nicely done.
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Also, I‘d love to hear of a single aircraft (type) that flies these days that has an FMS or RNAV navigation system or however you want to call it AND that does NOT have a form of an INS.
CRJ 700. Want me to keep going? Because I will just keep rattling off RJs... By and large the RJ fleet isn't going to have an INS, they are completely unnecessary for domestic operations and just add weight.
I was talking about commercial aircraft of which Boeings and Airbusses and Embraers and Bombardiers are making up the vast majority.In that case you are talking about the Part 121 fleet (14 CFR has very specific definitions for all of these terms which are helpful to avoid misunderstandings). Yes, there will be more INS equipage in the Part 121 fleet than in the combined air carrier fleet as a whole, but given the large market share of RJs, INS equipped aircraft are not nearly as prevalent as you seem to think. Fedex, for example, is 100% INS equipped but that is only because they like to keep their whole fleet legal for ETOPs/International. This isn't the case for regional airlines flying smaller equipment on domestic routes.
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Funnily though, in all commercial aircraft equipped with an FMS (which are 99.9% these days), lateral guidance is indeed done in true north. The FMS converts coded magnetic courses (depending on the ARINC 424 Path Terminator used) into true north courses because that is the reference system which is used by the INS. For the conversion there are a bunch of different sources for the magnetic variation, it could be table in which the world magnetic model is stored (updated every 5 years) or the magnetic variation of an airport or the station declination of a VHF Navaid. But that is a whole different discussion...
-The US commercial fleet isn't close to 99.9% FMS equipped, you won't find a source anywhere to back that. GPS and WAAS equipage rates are growing quickly as the ADS-B mandate approaches but GPS/WAAS does not an FMS make.
-Of all the commercial aircraft in service in the US equipped with FMS, a minority of them have an INS.
-Regardless of how the navigation system generating the course guidance arrives at its solution, it will be displayed for the pilot as a magnetic course overlaid on a magnetic heading instrument (this is true whether it is a conventional HSI, a digital projection of one in a glass cockpit, or even a basic DG and OBS head combination). One of the first things fledgling pilots learn about ded reckoning navigation is how to calculate a magnetic heading between two points; first a true course is measured off a chart, then it is adjusted for magnetic variation, wind, and possibly magnetic deviation to arrive at a magnetic heading to fly that will yield a given magnetic course (and ground track by extension). Whether done by hand with paper or in the background by a computer, the pilot is still not referencing true north in any way when actually airborne; he or she sees the world in reference to magnetic north.
Which brings us back to the OPs point: it is indeed strange and not realistic that BRAA calls from AWACs are given in reference to true north. After so long in this game I just unconsciously subtract 7 from any bearing given by an AWACs, and when I MP as GCI I convert into magnetic before transmitting (after telling the players all my calls will be in magnetic degrees and nautical miles of course). Perhaps the long awaited ATC upgrades will help this long standing issue.
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Northwind, I think you may have found a problem here. I have always used the ADF by selecting "DF" and "ADF" but that was self taught, I never read the manual carefully. However, I agree with your assessment that according to the TO you should only have to select "DF" and the ADF should be functional with the radio function selector still set at MAIN or BOTH.
I am away from home but I will test this when I can with the manual open.
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PM sent Slag.
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Speed Brake HOLD stops the speedbrakes. I am away from my machine but I believe EXTEND and RETRACT (or something to that effect) are the bindings you are looking for, maybe start there?
EDIT: Speedbrakes IN and OUT are the bindings you need. HOLD centers the switch. Honestly the best way I have found to see what your bindings are doing is to watch the speedbrake switch on the top of the in-cockpit throttle as you manipulate your joystick to see your inputs are actually doing to the switch. Good luck, zero issues using the same bindings I have always had running latest OB.
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A couple guys here had some ideas for this problem. I also seem to remember a gent that found unchecking “sync HOTAS at start” helped, along with the FFB unchecked as you mentioned. Terrible problem to have because it seems SO random.
Also super basic but have you done a repair on your DCS?
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We’re not on the same page here, so I’ll leave you to it.
True, I'm on the same page with the guy who solved the OP's problem 10 posts ago, which at the end of the day is the point of the forum.
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2) bind the UHF Radio Microphone Button to a button ( I use the mic push) and then it works both in the air and on the ground, and the NSW still works in the air.
I agree it's odd, but there we are. Must be a reason.
This is textbook operation per TO 1F-5E-1. What is odd about it? It is a perfectly sensible arrangement, I don't understand what kind of reason you are looking for.
Edit: Option 2 above is also the exact strategy espoused by Knock Knock in post #3 of this thread that I seconded in post #5.
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Nothing anywhere in any RL manual specifies which mic key to use, nor does it state that the throttle mic switch ceases to function once airborne; it only shows that the NWS will not key the mic on the ground. (If you can find a RL manual reference showing the throttle mic button ceases to operate in flight please post the page number, because I haven’t seen it). In DCS we must key the mic to even get air to start an engine. This means binding a key for a mic switch, and since one binding would only key the mic in the air(NWS) and the other binding (mic button) works in all cases, the simplest solution is to bind a single key to the mic switch. If the throttle mic button isn’t functioning in this manner in the latest version it is indeed a bug.
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It is. You don't know what kind of hardware the OP is using, so you can't claim anything is already bound to a NWS switch he might not even have. There is one button you can bind guaranteed to work regardless of WoW position, and it is the mic switch on the throttle. Just as Knock Knock said, shown on TO 1F-5E-1 pg 1-34. Why would you advocate using a button that won't work on the ground for comms when you don't know what kind of hardware the OP is using?
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+1 to Knock Knock for simplest solution. Just map the mic button (located on the throttle on the RL aircraft) and it will work on ground and in the air.
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Sig Test
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Well that took a lot of mental gymnastics to re-read and decode...
No argument there, I had to read through the thread several times before I waded in. Cheers
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I am not trying to be argumentative but the difference is clear. In posts 1, 3, and 5 he is specifically talking about the switch not resetting to center when intentionally selected to the wrong position. In post #7, he explicitly confirms this when clarifies with bbrz that he has no issues when he selects auto balance as designed (which is what you are talking about in post #9)— his issue is about how the system reacts when used as it is not designed.
Your issue would be a separate bug, as it would indicate improper operation of the system. If that is the case, it is obviously an issue, but it it not this issue. On the contrary, the OP is reporting behavior he believes is a bug but is proper operation per the -1.
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I've had this happen a few times with air-start missions. I'll have L LOW, so I'll flip the auto-balance to L LOW. Commence BFM. 50% of the time, the switch resets to center. 50% of the time, the switch gets stuck in L LOW...
Fair enough, but that isn’t what the OP is talking about. He is specifically talking about intentionally selecting R LOW in the situation you describe above.
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I was wondering how to get them back open once the aircraft is shut down.
The landing gear door switch on the F5E is in the right main gear well. Selecting the "OPEN" position on this switch allows utility hydraulic pressure to open the gear doors. Obviously this switch is not accessible to our virtual pilot. (Interestingly enough, some T38's have this switch in the cockpit behind the throttles where the F5 damper panel is located.)
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For example,when left fuel tank Fuel Quantity low and right fuel tank Fuel Quantity high,Right engine fuel system contains approx 550 pounds of fuel more than left engine fuel system.Turn AUTO BALANCE SWITCH to right,the switch does not rebound.
Not a bug, this is correct behavior. Per TO 1F-5E-1 there are 3 conditions which will stop autobalance operation...
- fuel quantity pointers are within 50 to 125 lbs of each other
- the low fuel level float switch in the supplying tank closes for more than 10 seconds
- the crossfeed switch is moved to "crossfeed"
Any of these three conditions deenergizes the autobalance holding solenoid and the autobalance switch springs to center. There is no logic provided by the system to ensure that the switch is moved in the correct direction when balancing is started; the system only knows how to stop transfer once the fuel is balanced (essentially when the quantity pointers overlap), but until the fuel gets really low (low fuel float), the system doesn't know which tank is low; that is up to the pilot.
I have never tested the system feeding in the wrong direction, but if it used to work as the OP says, it sounds to me like maybe this used to be modeled incorrectly and has since been fixed.
- fuel quantity pointers are within 50 to 125 lbs of each other
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If you are going to use CCIP you do not need DMT.
I tend to disagree and so does 3-22.5-AV8B, Vol. I. To quote...
“In light of the accuracy of the ARBS system, the limitations of the radar altimeter, and the inaccuracies involved in ADC measurement, every weapons delivery should attempt use of DMT designation. In some scenarios lack of valid DMT designation should become one of your tactical abort criteria.”
Harlikwin summed it up nicely in post 8, and I believe it is what Fri13 was getting at also. In this aircraft with CCIP annunciated in the HUD the DMT is how the target elevation is computed, and it will provide generally better solutions than RCIP, GCIP, or BCIP.
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Variable — Red GCI (CA)
[REPORTED]Is the GBU-38 JDAM still Borked ?
in DCS: A-10C Warthog
Posted
Thanks, that is interesting too, and it is just the kind of data driven discussion I think is needed! Do you have any insight on the difference there between the GBU 38 and 32? I would speculate accuracy isn’t really at issue, but that the PK is higher with the 32 simply due to increased mass.
I’m just fine with the idea that our DCS GBU38 should miss on occasion even under the best conditions, but when the discussion is always binary (aka “it is broke” or “it works fine here”), rather than percentage driven, it is hard to judge what is actually going on in the game.