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F86F Attitude Indicator


IvanK
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Is the representation of the AI correct ? I am referring to the the Digital Pitch Indication in the cutout window on the AI sphere. Its interaction with the "free floating" horizon line looks odd to my eye.

 

In all the reference stuff I have/found I don't see any degrees indication on the F86A-F series Attitude indicators. (The CA27 did but again it was different to the DCS depiction and a non US instrument anyway).

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Here is the issue ... it has a distinctly "Russian" AI feel to pitch attitude presentation.

 

This is what we see at present:

DCSF86ADI1_zpsd045121f.jpg

 

We are steady at 20degrees Nose up. Yet looking at the pitch scale digits they get smaller ABOVE the aircraft symbol but bigger below the aircraft symbol. So if we increase pitch attitude the Pitch scale comes UP to increase the digital value. This makes no logical sense in Western AI's.

 

Below is my dodgy artwork on how I think it should be.

Again we are established at 20 degrees Nose Up. As we increase pitch then the digital scale should move in a natural sense with the higher Pitch attitude values ABOVE the aircraft symbol.... the Sphere with pitch markings on it rotates naturally down towards the aircraft symbol to read off increasing pitch attitude.

 

DCSf86ADI2_zps48ae8e5d.jpg

 

Finally an image of an F86F-40 Attitude indicator, which I believe is a standard USAF J8 indicator this agrees with just about every reference image I can source on F86E-F. That is there are NO Pitch attitude reference markers on the AI sphere at all.... its a true Artificial Horizon where pilots use "Bar Widths" to determine precise IF references. (Some Canadain and RAAF CA27/32 AI had a different AI that used another variation of attitude references)

 

F86F40ADI_zps18a92e52.jpg

 

J8ADI_zps5b49574a.jpg

 

J8 Presentation throughout a loop Source TP55 USAF Instrument flying Manual:

 

J8loop_zpsd659a00b.jpg

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Should be easy enough to change the attitude marks texture to plain black.

 

...Oh, and if we're talking about back-asswards instruments don't get me started on the heading indicator :-0


Edited by jocko417
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I stand corrected. I found a Ref for Pitch attitude references on the AI for late model F86F. They appear in this section of the manual regarding Manual Pip control system but not in the earlier general system description.

 

So the pitch reference marks were there ... though they are still working in reverse and should imo be corrected as per the first post:

 

F86AIwithpitch_zps8496acb5.jpg


Edited by IvanK
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The more you dig the more variations you find. The TO implies that some aircraft had pitch references on the AI and others didnt depending on mod state. on those aircraft that DIDNT have pitch references on the AI they had the Dive angle marks on the canopy.

 

Which implies that if the AI had pitch references then the canopy dive angle marks were not applied.

 

F85divecpy_zpscbccf8fe.jpg

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I stand corrected. I found a Ref for Pitch attitude references on the AI for late model F86F. They appear in this section of the manual regarding Manual Pip control system but not in the earlier general system description.

 

So the pitch reference marks were there ... though they are still working in reverse and should imo be corrected as per the first post:

 

F86AIwithpitch_zps8496acb5.jpg

 

If you look closely, you'll see the aircraft in that image is actually in a 70 degree nose down condition instead of climbing as in your example. Therefore the scale in the sim is actually correct (numbers decreasing from the top in a dive and decreasing from the bottom in a climb).

 

It's difficult to see in that image but I have a higher resolution version from the same flight manual and can assure you it is correct.

Screenshot_2014-07-29-12-10-03.thumb.png.67d17a46ffd6989144424bec428555d1.png


Edited by Sabredog
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Yes I see that in your graphic Sabredog, but its also worth noting that the Sky pointer is missing in that graphic, which is strange.

 

If we accept that the pitch reference digits are correct then the issue lies with the Attitude Spheres rotation direction. At present its rotating the opposite way to pretty much every Western Attitude Indicator I have used.

 

Lets take the 70 degrees nose down example. We want to push the nose to 90 deg nose down. Here is the AI depiction in the DCS F86 with us at 60deg nose down:

 

F86ADi-60nd_zps419e71af.jpg

 

Basic logic says I am at 60 degrees nose down, 90 degrees nose down is below me. Since the AI is meant to represent the outside world then logically the 90 degree marker should also be below me ... its not in the DCS F86 its sitting above me !!!

Its also saying the Horizon is above me (correct) but its also saying that 90 degrees nose down is above me ??? thats obviously wrong.

 

In the DCS F86 as we push from 60deg nose down towards 90 degrees nose down the attitude sphere is rotating from top to bottom to show an increasing dive angle !!! ... thats unnatural and opposite to pretty much every western AI logic.

 

Look at this graphic of the A10A AI when 70degrees nose down.

 

A10-70nd_zpsae43f214.jpg

 

I am at 70 deg nose down, 90 deg nose down is below me and I expect to see the 90 degree pitch refrence to be below me ... on the A10 AI it is .. logical.

 

Again we push to achieve 90 degrees nose down, as we push down the underlying attitude sphere rotates bottom to top towards the 90 degree nose down reference mark. In other words the Aircraft symbol is flown in a natural sense towards the desired pitch attitude

 

So the fix IMO is to re-text the pitch reference marks and keep the attitude sphere rotation the same or keep the existing pitch reference marks but reverse the attitude sphere rotation direction such that it operates in a natural and logical manner...... as it should.


Edited by IvanK
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The system is properly modelled to what it was that specific attitude indicator.

Those were early models and they had a different behaviour than modern western ones like the one of the A-10C for instance.

 

On this indicator up to the first 27º either dive or climb, the reference is the "horizont bar" and beyond those 27 degress the the spere is the moving reference.

 

attachment.php?attachmentid=101931&stc=1&d=1406712066

 

It didn't worked as the modern ones neither it had the same performance and capabilities than modern instruments so you cannot apply today's instrument logic to it.

 

And yes, it takes time to get used to this but this is how it was by then :joystick:

 

Note Thanks to this post I just detected a small issue with the movement range of the horizont bar on the 27º range that will be reported inmediately Thx :thumbup:

attitude.jpg.b2d759c06f763367b82f3e48de412b13.jpg


Edited by Furia
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If it helps, here's some pics of mine, it doesn't have the pitch angle markings on it, just the climb and dive markings and associated 8 balls for 90 deg... These are pics, not video, you'll have to trust me as I flipped this thing around to document how the Climb and Dive markings on the sphere behave at high and low nose attitudes.

 

CBC08689-5848-4283-A240-C1C50E379957_zpss1uvhajc.jpg

 

Type J-8 Attitude Indicator, as manufactured by Bendix.

 

BA8B6C25-3C4B-42E6-8E5F-7EAD48765262_zpswjjlvcvh.jpg

 

The Climb marking appears from below and is seen first before the 90 deg marking. NOTE - I know it appears you are diving in this pic given the airplane symbol is BELOW the horizon bar but this is due to the instrument being unpowered and the gimbals flopping around inside. I only mean to illustrate the Climb and Dive markings.

 

A67E5C58-DFF8-424B-9BED-6EA506AA2894_zps39qatvfz.jpg

 

The Dive marking appears from above. The horizon bar, as stated, is separate from the sphere behind it and only travels the first 27 degrees from the horizontal.

 

More crap from my Man Cave... Most instruments manufactured by Kollsman. Although used in the F-86 they weren't specific to the Sabre, but used by many aircraft of the era. Somewhere in the basment is an EGT and a fuel flow gauge...

 

B52D4E68-6748-431E-9D4D-4C8690375613_zpsjkgmxiob.jpg


Edited by jocko417
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Still researching this ADI with pitch attitude marks:) I found some references in the F86F Maintenance manual:

 

F86FMaint_ADI_zps35efb839.jpg

 

This implies that perhaps only DIVE reference marks were on the sphere ?

I then found this image of an F86F panel. The AI appears to have some form of Pitch reference marking on it but it seems only in one direction.

 

F86FpanelADI_zpsb61f3779.jpg

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A bit off topic here, but those diagrams you posted also seem to show that the windshield frames are markedly thicker than the one in-game right now. But a Beta is a Beta. And what a fantastic one it is so far!

 

You'd base your conclusions on a diagram, which could be utterly out of scale, and is designed merely to present information on the location of 3 instruments? Very scientific. I'd suggest that Belsimtek used far more empirical measurements.

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I then found this image of an F86F panel. The AI appears to have some form of Pitch reference marking on it but it seems only in one direction.

 

Those markings are on the ownship indicator post from what I see in the attached picture?

 

The pitch decals are on the sphere, according to references as posted. I assume the sphere to contain the gyro and be earth-fixed, meaning the displayed behaviour is correct. It will move the opposite direction of the bar, as the bar (as in any modern western AI, even when the bar is replaced by an earth/sky depiction) has linkages which reverse the direction of movement.

 

Cheers,

/ Fred

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Still keeping this alive :)

 

Yes Fred I think I agree its on the post.

 

Now WRT the markings themselves, see this from the Flight Manual:

 

F86ADIMPC_adi_zps5f5dc9a8.jpg

 

The wording is quite specific and only refers to Dive angle markings on the ADI, nothing about pitch. If this is the case then no ambiguity with respect the markings on the sphere would occur. If you see pitch marks you are in the dive area. The whole idea of these markings at this stage (before the MM series ADI's came into service) was to indicate DIVE angle and was introduced as part of the MPC system.

 

So do the devs have other info that categorically illustrates both Dive and Pitch references on the sphere ?

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