not used to the dc-8 autopilot

[darrenvox]

i tried the other night to do a flight cyvr to phnl but as i started to put the autopilot the plane went all crazy and wobbled all over the palce. i just downloaded the panel earlier yesterday in the aft, and really really like it but the autorpilot is very easy to use but for some reason the ias hold wont hold (which is ok, i fly the 737=200 alot and it sometimes doesnt allow the ias speed to be held

i also couldnt make the altitude stay for any length of time, but i could get the heading to work just not the others

im pretty good with the older autopilots just wanna know the correct way to fly with the dc-8 autopilot

[aerofoto - HJG Admin]

"DARRENVOX" .... I moved you posting to HERE" .... our "DOUGLAS AIRCRAFT SUPPORT" forum page .... where it's more appropriately placed


"PILOT ERROR" I suspect .... because there's nothing wrong with the DC8 AP provided it's used correctly to start with

I was doing some flight testing using our DC8 simulations the other day and can confirm that everything works well .... as it's supposed to.

This may help you understand it better though ....

AUTOPILOT NOTES

The AP on all HJG DC8 panels functions as follows ....

The AP is activated by selecting the SERVO SWITCH to "AUTO PILOT" position.

When the AP is engaged it will also hold the aircraft at whatever ROC/ROD was established at the time of its first being engaged.

During AP controlled flight the aircrafts ROC/ROD can be adjusted using the "VERT SPEED" thumb wheel. Careful mousing at the bottom of this wheel ("CLIMB" position) will set and control ROC .... and similar mousing at the top of this wheel ("DESCEND" position) will set and control ROD .... both in proportion to mouse input. Work on the theory that each mouse click of the VERT SPEED thumb wheel roughly corresponds to a command of approximately 100 FPM ROC/ROD.

To engage and hold a specific altitude the aircrafts ROC/ROD should first be set to no more than 500 FPM .... and less during the last few hundred of climb/descent toward any target altitude. As the altimeter needle/s indicate precisely the desired altitude simply mouse click the center of the VERT SPEED" thumb wheel. The aircraft should then begin to maintain altitude. The aircraft will at first drift slightly above and below the selected altitude .... this is quite normal. The aircraft will eventually settle into a perfect altitude capture after a few moments. Care should be taken to engage AP ALT/HLD mode at the precise increment of any desired altitude .... paying close attention to both the altimeter needles and the ROC/ROD gauge is essential.

To commence further climb/descent simply mouse either the bottom or top of this thumb wheel accordingly. This action disengages the ALT HLD function without disengaging the AP .... then select whatever ROC/ROD is desired by mousing either the bottom or top of the VERT SPEED thumb wheel accordingly .... as described above.

The VERT SPEED" thumb wheel will not .... intentionally .... function in manual flight mode. In this mode trim must be set manually in order to set any desired ROC/ROD. The Trim warning horn will be triggered in response to each manual input. This warning horn will not be triggered when Trim is adjusted during AP controlled flight mode.

There is an "IAS HOLD" selector on the AP mode rotary switch located the far left of the AP. This should not be engaged below 300kts. It is important to note that when engaged IAS HOLD will adjust the aircrafts pitch attitude to whatever it determines necessary in order to maintain a specific speed. Typically .... if more power is then applied the AP will increase the aircrafts pitch attitude in order to maintain speed .... and if power is then retarded the AP will decrease the aircrafts pitch attitude accordingly in order to maintain speed .... automatically adjusting the aircrafts ROC/ROD in the process.

IAS HOLD and "ALT HOLD" cannot be engaged together. One or the other mode only must be used.

IAS HOLD is not an AT .... and should not be used as such. Few DC8's, if any, were ever equipped with AT systems.

A large "TURN" knob is located in the center of the AP. This can be used to turn the aircraft left or right during AP controlled flight .... but only when the AP mode rotary switch is set to "TURN KNOB". It has been observed that this turn knob may not fly the aircraft through perfectly smooth turns. This is a known FS bug associated some panels. Alternatively "HDG SEL" may be used to ensure perfectly smooth turns during AP controlled flight.

If the AP mode selector switch is set to "HDG SEL" then turns may be controlled by moving the "HEADING BUG" located on the HSI instrument on the main panel. Manually controlled turns are still possible per joystick/yoke input even during AP controlled flight, but, only when the AP rotary switch is set to TURN KNOB".

If the AP mode selector switch is set to "VOR LOC" then this will allow the aircraft to engage and track along any particular radial emanating from a pre-tuned VOR signal. VOR radials should be intercepted at less than a 20 degrees to the intended beam/course. Engaging the AP VOR/LOC at too acute an angle of intercept will cause the aircraft to weave as it endeavors to capture a VOR beam. It is always best to use HDG SEL to first align the aircraft with any VOR signal. Once established on/or near the set beam/course then select VOR/LOC to acquire it. The aircraft may still weave slightly at first. This is a normal FS response. The aircraft will settle down to smooth tracking after a few moments.

The AP mode selector switch also features an "ILS" mode to allow coupled AP cntrolled ILS intercepts during approaches to landing. All landings should be accomplished manually.

On DC8-61, -62/63, -71, and -72/73 panels only, a cautionary red lamp (located on the main panel Bowtie instrument) will be seen to flash repeatedly whenever the AP is disconnected. To cancel this lamp simply mouse click the silent "hot point" located just above the center of the Bowtie instrument on these panels in order to extinguish it.

The above extract comes from my "DC8 PANEL INSTALLATION & HANDLING NOTES" posting on the ABOUT HJG AIRCRAFT forum page .... which will, soon/later, be moved, when I complete writing the new/revised edition !!!!

Whenever the AP IAS HLD mode is selected the DC8 simulations are going to become a little sensitive to power adjustment .... and one therefore needs to be "cautious".

By selecting this mode one is, effectively, commanding the AP to control airspeed by way of the aircrafts pitch attitude.

Once IAS HLD is activated .... the AP will raise, or lower, the aircrafts nose ... to whatever it determines being the best pitch in order to maintain the aircraft airspeed at whatever was being flown when this mode was first activated.

"IF" more engine power is applied .... then .... the AP will use this potential to increase the pitch attitude in order to maintain airspeed .... AND .... "If engine power is reduced then it will do precisely the opposite, by lowering the pitch attitude in order to maintain airspeed.

IAS HLD should not be considered an AT though .... and .... IAS HLD and ALT HLD AP modes cannot be engaged together.

One doesn't really want to engage this mode until above 300 KIAS (in FS) .... and .... on those "very rare occasions" I have, myself, used it I've always been above 10.000FT.

On aircraft like the early A300B's, B747's, DC10's, and L1011's .... IAS HLD could, and normally was, engaged at a much earlier stage .... often just after T/O .... BUT .... it must be remembered DC8's represent much more primitive/earlier technology.

I recall an ATI PFE (John DETRICK) once explaining to me that DC8's were/are often hand flown .... even right up to cruising altitude .... with both pitch and power being adjusted manually throughout the climb and in order to get the desired performance .... and which, as he also explained, was/is something requires/d "REAL SKILL" on the part of the pilot/s flying the aircraft.

DC8's, like the B707, CV880, and CV990, because of the technological era they represent/ed are, mostly, hands-on, and manual, aircraft .... even in DC8-70 SERIES form.

In FS .... one's best advised to engage the AP after T/O and clean up .... and then .... use the AP pitch/thumb wheel in order to control ROC/ROD .... as well as making "very subtle" manual power adjustments, to keep airspeed under control.

"IF" one's not used to this .... or rather .... until one "IS" used to doing precisely "THIS" .... then the DC8's can really keep one concentrating, and busy, which isn't a bad thing .... because it really teaches one to "FLY" rather than be flown

See how you go !

Mark C
AKL/NZ

[walterleo]

Hi:

Mark did a lot of work here to explain one simplke fact: IAS HOLD is not an AT. Most airplanes of age didnt have AT, that which had some didnt use it in cruise, climb or descent. Old AT is a great help on ILS but in other situations it can be even dangerous for the engines or the airplane.

Walter

[aerofoto - HJG Admin]

Some of the DC8-60 SERIES aircraft did, in fact, have AT systems (though nothing like those systems installed on A300B, B747, DC10, and L1011 though) .... but .... I also remember John DETRICK explaining, to me, that this older/earlier version AT system never used to work reliably .... and eventually .... the majority of crews at the majority of DC8 operator airlines around the world simply opted "not to use it at all".

Mark C
AKL/NZ

[walterleo]

Hi Mark:

On the Tu 154M which had an AT with automatic Go-around its use was only permitted on ILS approaches. Even then it had to be switched off if the calculated approach-speed could not maintained exactly. The crash of Polish Air-force 101 had also to do with the crew using AT on a non-precision approach which masked an increasing tailwind and let the engines spool down to unsafe values.

The stock AP of FS works very unrealistically, at least for older jets.

Walter

P.S.: IAS hold works great for climbs and descents, as long as you trim the plane first for the desired speed and vertical rate. The descent or climb you can change afterwards easily changing power. In climbs you never will be in danger of out climbing the operational limits. That can happen with AT commanding full climb power and AP holding climb rate or attitude while airspeed decays. An Aeromexico DC-10 nearly fell out of sky by this erroneous procedure.

[aerofoto - HJG Admin]

i also couldnt make the altitude stay for any length of time

Altitude can't be maintained/held using the AP IAS HLD mode.

Another very minor clarification in regard to our DC8 panel AP's .... this time in regard to the AP VERT SPEED control thumb wheel and its ALT HLD function ....

The ALT HLD button on the VERT SPEED thumb wheel is located "just a fraction below its centre point".

One must use one's mouse to feel around there for its "HOT SPOT" .... and one will then find it.

"IF" one does not use this "precisely" then the AP ALT HLD mode simply won't/can't be engaged.

"IF" .... this ALT HLD function doesn't seem to work despite one being certain one's using it precisely as described within my "AUTOPILOT NOTES" extract above .... then .... one may have a very rare situation (which I've only ever seen on less than a handful of occasions in my entire 10 years of experience using all versions of these panels) which can only be fixed using FSUIPC.

Thie fix is simply to have FSUIPC installed .... "even in completely unlicensed form" .... and with its "MINIMUM DEFAULTS" option selected !!!!

This action "WILL/SHOULD" definitely fix any such issue .... "TRUST ME" .... because I've seen the evidence of that for myself as hinted at above

"IF" one already has FSUIPC installed .... and one still thinks one has an issue to be reconciled using the DC8 panel/s AP controlled ALT HLD function .... then one really needs to look "more closely" at how one's flying the DC8, and in particular, how one's using the AP system.

Mark C
AKL/NZ

[+mrfaosfx]

The AP on the DC8 is scattered all over the panel which can be confusing to someone who has never flown one.

[aerofoto - HJG Admin]

Actually .... on all of the DC8's I've seen/jump seated on (AIR NEW ZEALAND DC8-52's and the HAWAIIAN DC8-63) .... the "principal AP modes" are located on the AP unit itself .... usually a SPERRY (I think it was in those aircraft I was most familiar with) and whic was, itself, locaterd on the Center Pedestal .... with other FD Trim and actual Course/Heading selector related functions located on the top portion of the center main panel, immedistely below the windshield (a configuration which our 2D panels represent more-or-less quite authentically) .... BUT .... systems/instrument standard, and layout can, and do/did, differ considerably among DC8 operators. Especially in regard to a lot of the very early production aircraft versions.

There's an old saying .... "see 1 DC8 panel/flightdeck and you've effectively only seen one DC8 panel/flightdeck".

Mark C
AKL/NZ

[darrenvox]

normally i just fly the dc-8 with the default 737/747 panel and dont matter much about it but just saw a video on the screenshot area and downloaded the panel and sound as i really wanted to try it out but then i get out over the water and the whole plane goes wishy washy kinda thing...im used to the older (manual autopilot) like the 732 and 722 but this one confounded me...so ill try it again!!

ok so i tried to do it again...

heading hold a-ok
speed ok (wont hold but i can make do with that)
altitude hold (the number i set beside the grey letter A, wont seem to hold at all, ie just did a flight now and well i set it for 16000 and it made it to 25000 so go figure...cant figure it out..i just want to set it and forget it!!

[walterleo]

Hi:

Darrenvox:

There is exactly the misunderstanding of an old AP provoked by the stock FS9 AP: The old AP don't have an altitude acquire function, when you select 25000 on the window you mentioned its only a reminder of the altitude you want to go or are cleared to. 1000 ft or so before reaching that altitude you will hear a chime, but its not the AP which is programed to that altitude.

Kind regards
Walter

[aerofoto - HJG Admin]

Again .... there's nothing wrong with the AP in any one of the HJG DC8 panels we offer.

In fact I've been using them today in regard to other testing and development work which I've been s---l---o---w---l---y undertaking over the past 20+ months .... and without the slightest problem.

"IF" your experience isn't possibly being provoked by the absence of the FSUIPC (which ordinarily shouldn't be required .... BUT .... have you tried it anyway like I suggested yesterday ?) .... then it's got to be caused by "something you're either not doing right or misunderstanding".

The current versions of these DC8 panels are now 5 years old and they're very well understood .... and have been proven to run very well too .... provided they're first used properly of course.

Just a bit of advice for you since you're obviously new to these panels .... and also possibly new to the art of actually flying old technology as well ....

When engaging the "ALT HLD" function on the AP .... one should click slightly below the center point of the "VERT SPEED" thumb wheel .... directly on its hot point which is located fractionally below that grey letter "A" which you mentioned.

As Walter sais .... "AND QUITE CORRECTLY TOO" .... one can't just set up the DC8 in any climb/descend mode .... and then just forget about it .... because the DC8 AP has no automatic altitude capture mode .... and that's the way DC8's are/were !!!!

After activating the DC8 AP the aircraft will remain at its established ROC/ROD. One then needs to "manually" adjust engine power to control airspeed .... and then .... "manually" increase/decrease the established ROC/ROD by using the "VERY SPEED" thumb wheel.

The altitude value (target altitude) dialed into the "ALTITUDE" window on the main panel is simply there to remind the crew what altitude has been targeted .... and/or .... what altitude the aircraft has been cleared to.

As one approaches within 1,000 FT of the set target altitude the altitude alert will be triggered automatically .... and .... should the aircraft ever exceed this target altitude by more than 200 FT then the altitude alert will once again be triggered automatically.

One needs to monitor ones own progress towards target altitude .... and .... during AP controlled flight .... using the "VERT SPEED" thumb wheel .... one also needs to progressively reduce the ROC/ROD .... to less than 1,000 FPM within the last 1,000 FT of the target altitude .... then less than 500 FPM within 500 FT of the target altitude .... and finally to less than 200 FPM within 200 FT of the target altitude. This procedure is necessary/recommended in order to ensure smooth altitude captures. As the altimeter gauge needles indicate precisely on the selected target altitude .... one needs to click on the center point of the "VERT SPEED" thumb wheel .... and the aircraft will then begin its altitude capture. From this point one needs to adjust engine power in order to control airspeed and avoid either over speeding or stalling the aircraft .... and then concentrate on everything else too.

The DC8 panel AP represents a very early model .... and when I say that I mean an early model as is/was installed on these aircraft. The type of AP represented in the HJG DC8 panels .... along with the way it all functions in FS .... is actually a very good representation of the real thing.

Remember .... DC8's are "OLD TECHNOLOGY" and can't/shouldn't ever be flown like an AIRBUS or other late model jetliner.

I can't stress the words "MANUAL" and "CONCENTRATION" more strongly .... because the DC8, like the B707, CV880, and CV990, is a "manual/hands-on" aircraft which requires concentration and constant adjustment along the way .... even during AP controlled flight.

Today .... we seem to be entering an age where these facts are quickly being forgotten .... even overlooked .... OR .... am I just beginning to "show my real age" ;D

Mark C
AKL/NZ

[walterleo]

Hi Mark!

The beautiful thing about HJG that you maintain the memory of this wonderful machines and the art to handle them. This airplanes were real "pilots" airplanes.
A friend of mine who was MD 80 check-pilot before got on a DC-8 cause of seniority and interesting routes, he was not happy with that "advance", compared with a MD-80 the systems seemed him outdated and flying reminded him about his days as captain of a Superconny.

A Russian ex Tu 154 and now B 737-800 pilot wrote on the PT forum: Changing to the 737-800 we learned how difficult was the Tu-154.

But praise to HJG that its simulations revive that kind of "flying" and the professionalism of its former pilots.

What in FS is still more demanding than on the real thing: On this old jets were sitting up to 4 people up front. In FS we are alone, the better the simulation the more demanding it gets for its "single pilot".
Kind regards

Walter

[Alejandro]

Just curious... there is some way to have two people sharing the same plane? Just the way some real pilots fly the plane while the second on board manages the flaps, gears and comunications?
I mean using two different computers, not putting one's arms over the other?.

[darrenvox]

ok i will go and try it out again, sorry its just im not used to the new dc-8 panels. Thoygh i know how to use the 727 and 737-200 autopilot which may be older or may be newer not sure

[aerofoto - HJG Admin]

NOT A PROBLEM .... but .... "IF" you're talking about the B727 panels which we/HJG offer here .... then you shouldn't, then, be experiencing any difficulty with the manual ALT CAP mode using the DC8 AP .... because they both function similarly. The only difference being ALT HLD on the B727 AP's is activated by a switch .... whereas on the DC8 AP's it's activated by that button located more-or-less in the center of the VERT SPEED thumb wheel. Neither AP .... nor that fitted to the RP B737-200 panel also .... feature automatic ALT CAP modes through the AP.

Mark C
AKL/NZ