Simviation Forums

Ok here's what i understand are the steps for takingoff on the 737:

1)lights on
2)I dial in the Autopilot: 250kts 18000 alt, 2500 fpm
3) 5 deg flaps
4)F/D on and A/T arm

When i get takeoff clearence i increaese throttle to 90%....
at 140knts pullup..... as soon as i get a positive rate of climb, gear up, then engage the autopilot on and click on the "alt".

BUT!!!!..... when i click the "IAS" on;  N1 drops automatically to 60%   sometime even less than that!!! and ofcourse there is nothing i can do about it!. IT dont seem normal (gets kinda scary too) ?or is it?

What am i doing wrong?

I also turn the IAS well below 250, and once engaged the autopilot if i let go the stick the nose drops!!!!

Please help me

ok here goes may be wrong but you never know.
make sure both the FD and the auto pilot are on first of all.
as for the engines spooling down a little, remember it needs alot less power once in the air than to get it off the ground, if you watch the speed closely you'll see it shoot up to 250 in a matter of seconds, the nose dropping could be a cause of many a thing, forgeting to turn on the AP aswell as FD switch,
and also remember the higher the engine output the lower the angle of attack to climb
correct me if i am wrong and please reply if this of no help

If you are flying an addon a/c (aircraft) then it is probably something wrong with the autopilot settings in the aircraft.cfg file.

If it is the default with an addon panel, then substitute another autopilot gauge for the one that is there and see if that makes a difference.

If it is the complete default aircraft, then I'm not sure about anything, but you may try reloading either the specific a/c or reloading FS2002 from scratch (a real pain).

You may also try waiting until the a/c has reached its designated altitude and/or airspeed.  That is what I always do.  Engaging the autopilot just after takeoff has resulted in many realworld accidents.

I think your problem is you are setting autopilot too soon & in the wrong way.

Set AP in stages.

Don't engage AP until you are well established into your climb & more or less on your desired heading. 6-8000 would not be too far wrong as an altitude to think about AP.

Then set AP with an Alt of - say 10,000ft & an Airspeed of say - 100 kts above your current airspeed. & increase accordingly until you achieve your desires Alt, Heading & Airspeed.

Have you read the Tute I did ?
http://www.simviation.com/fstutorial_nav1.htm

Ya,, what Pete said,, and (this is just me)  I've never had a use for the F/D. All it does is "suggest" things via visual cues,,,so I leave it alone,, (one less thing to set while you're already in a busy cockpit)...

Yes Pete!!  thats  it!  Thanks a lot!  the problem WAS i was engaging the autopilot too soon!

Bret! i turn on the F/D, but like you i find very little use for it!  except for the take off  where i follow only the horizontal wich gives me i good idea of the degrees to pull the nose up

F/D also turns confusing when landing! when i follow the vertical needle. better use the VOR ofcourse

But thanks a lot for your Data guys

Appreciate it

One more thing!!!!

When i'm ready for takeoff I click "alt" (without  engaging the autopilot yet), so the F/D moves up to 4 to 5 degrees.  then when i'm airborn i just have to follow the F/D at least for 10 to 15 secs only then i engage the autopilot.

For me (I think) it solves the problem for many people posting that  when they take off their FPM sometime go up to 6000fpm and seem unreal

Now....(and here comes the good part)  I used to dial 250kts, but now that i know that i must engaged the autopilot b/w 6-8000 feet (and its known that 250knts below 10,000ft) do you think its better to dial in 280kts first of all????

I dialed in 250kts b/c i saw many posting that

And one last question if you please.....  what is your FPM below 10,000 and below 18,000, or better  yet, what parameters do you use for  FPM in  the 737????

Because once I engage in the autopilotl 2500 FPM i'm stuck with that till my cruise altitude, and i know thats not correct

I hope this is not too much trouble

Thanks again for your help, wich I know will be a lot of help for many of us!!!!!!

JC.

I dont know why you think your stuck with the 2500 fpm after you set it, you can change your vertical velocity at any time.
one of the other problems you may encounter with the autopilot is being in an out of trim condition when you engage it.

Jaythree:

Its a real honor for me for your reply! i am also a civilian working for the Honduran AirForce!

Its not that i think that im stuck with the Autopilot, maybe i didnt interpret myself correctly, what i meant was, and what i want to know is; the rate of FPM in the 737 below 10,000 and below 18,000.

Because i Know you dont maintain 2500 from takeoff to climb to cruise altitude; and i think it has to do alot with the IAS.

With regard to the "cheat" what i do is that when i'm lined on the runway, I just engage the "alt hold" without yet turning on the autopilot ofcouse.

When I do this i can see how the F/D moves up 4 to 5 degress.

Then I begin my takeoff roll, When in pullback, I try to maintain nomore then 2500FPM(manually) and follow the F/D horizontal needle  wich will go up to 15 to 25 degrees if im correct,

At about 3000 ft I engage the Autopilot (but only with the alt hold on) so that It maintains 2500 and i can acupy myself with other things.

My problem was, i think, that i engaged the A/T arm and IAS hold too fast just like pete said.

But all your data i very useful for me too, and many other who read your reply (just look how many have viewed this post  ;D)

Because I think you are right that there is a lot of misinformation outhere. I read in a post to engage the autopilot AS SOON as the gear was up, and that that's the way the "big boys do it"

So you see.....

One more thing, I visited vusaf!  very  KOOL!!! (I didnt know about it)  Looking forward to joining and seeing you there!

Thankyou very much for your replies and concern.


Juan Carlos

P.d. can you please send me the link to download the tomcat or the f16?  ;)

I apreciate you reply, and I like to help, just havent really been on the public boards much. finding more time for it lately.
as for links to aircraft, the VUSAFs hangar is locked due to the fact that the unit had a reputation for ringing out all the possible downloads and using the one with the most bang for the buck. that along with the server that we pay for allows for a fairly high-speed download.
all this combined to the point that there were a lot of non-members downloading form us. ( at one point we had only 40 members but were getting close to using up all of our monthly bandwith due to files being downloaded. and were looking at an additional monthly charge. This VA is kept alive by it's memebers and a very few of us actually throw our own money at it ( I myself paid for the hosting for the first year, I dont know what the current commander is doing for finance)
in any case Fate01 put a password on our hangar so we wouldnt incurr the additional charges. It's a shme we had to do so, but the only alternative is bite the bullet and pay for it, or possibly look for advertising (both unaceptable solutions)
In any case all of the aricraft are available either on simV or the other sites (yeah Pete this is your board so I wont say it ) I thought there was a list of the files on the site so non-members or recruits could search fro and download. I'll take a look and if it isnt there bang on a few doors to see if we can get it put up.  I'd give you a ilst but I'm not in a place where I can do that right now.