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Guest greggs

Vref Tables?

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Guest greggs

I was thinking of making a FsBuild2 .tld file for the PMDG 737s. No problem - the manual is chock full of tables for landing and take-off settings. Wait... hey, where is the Vref stuff?A quick google does not seem to indicate anything about setting the Vref aside from consulting the FMC for values. That can't be true in RL, a pilot should have something in case of systems failure to use.Of course it would be cool if PDMG could cobble up the performance data file for FsBuild to incorporate - but I know they're a bit busy right now. It would be nice if someone could supply the Vref tables for the NG series though - would be useful for those of us who like to hand-fly a landing too.Gregg Schoenberger

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>A quick google does not seem to indicate anything about>setting the Vref aside from consulting the FMC for values.>That can't be true in RL, a pilot should have something in>case of systems failure to use.This is an interesting question. I believe dual FMC failure would be very rare indeed and if it happened pilots could guess their Vref (from experience) with good approximation, go to an airport with extra long runway or contact their dispatch center. Vref depends on your flaps, constantly changing weight so perhaps it is left to FMC to calculate it in real time. And if they really had a dual FMC failure they would probaby be very busy sorting other things out and Vref would be their last worry.Greetings from Oakland, we are neighbors.Michael J.WinXP-Home SP2,AMD64 3500+,Abit AV8,Radeon X800Pro,36GB Raptor,1GB PC3200,Audigy 2http://www.precisionmanuals.com/images/forum/747400.jpg


Michael J.

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Guest wee_davie_2612

Hi Gregg,There are indeed tables in the AOM. [a href=http://www.ibsw08346pwp.pwp.blueyonder.co.uk/vspeeds.pdf]Here is a set[/a] of them I bundled together from a real life 737 AOM. You'll probably find that they show a couple knots difference from the speeds that the FMC calculates, most likely down to the fact that the FMC has much more precise data to work from, but they are well within reason.Hope that helps,David

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Here's a .tld file I've done for the PMDG -600 based on the real world QRH speed tables.Enjoy,


Mats Johansson
PMDG Flight Test Dept
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| Asus Z270-A | Intel i5-7600K @ 4.8 GHz OC/H2O | nVidia Geforce GTX 1070 8GB OC/O2|

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Guest greggs

David,Data from a AOM is great. Do you recall which model of 737 this was for?GreggS

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Guest greggs

Thank you Mats!I've got this hope that full set of detailed tld and prf files for the PMDG aircraft could be made for use by FsBuild 2.x. I really like the way it does fuel calculation and reporting. The PMDG tool is nice too, but it does act a bit erratic in actually loading fuel onto the bird and getting ZFW for me.Of course, if the results of my work are something I feel are good enough I'll share them for you all to use.GreggS

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Gregg,I think the digit at the top right corner of the tables denotes the type. First table for the -700, second for the -800 and the last for the -900.TGIF,


Mats Johansson
PMDG Flight Test Dept
Boeing777_Banner_BetaTeam.jpg

| Asus Z270-A | Intel i5-7600K @ 4.8 GHz OC/H2O | nVidia Geforce GTX 1070 8GB OC/O2|

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Mat,You're correct. These are for the 700, 800, and 900 series. But there's still one thing that puzzles me. For example, the 737-700 maximum gross weight is 153,500lbs, occording to the PMDG manual. Why does it list at the left under Weight as 170,000lbs if the maximum is 153,500lbs?Ken.

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Hi Mats,I've downloaded the tld file but the numbers are all jumbled up and I can't tell where they supposed to go. Is there a way to correct this?Ken.

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Guest tmetzinger

>Mat,>You're correct. These are for the 700, 800, and 900 series.>But there's still one thing that puzzles me. For example, the>737-700 maximum gross weight is 153,500lbs, occording to the>PMDG manual. Why does it list at the left under Weight as>170,000lbs if the maximum is 153,500lbs?>>Ken.This could be for several reasons:A misprint - doubtfulThe -700 airframe could actually be limited at 170+ KLbs, but due to brake energy limits it could be operationally limited to less.Could be for the BBJ variant of the -700My Continental flight manual dated 11/15/02 has max ldg weight for the -700 at 128,000 lbs in their limitations section. This could be a continental limit and not a boeing limit, which seems likely as the Vref table for the -700 is exactly the same as shown earlier, with the envelope up to 170,000.So, my final guess is that there are procedures and waivers for getting the -700 up to that weight and thus there's a table in case one ever had to land at it.Best wishes

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Guest wee_davie_2612

Hello all,Those tables came straight from the COA AOM dated 11/15/02 #41.I'm not sure why those weights are shown as the 700 can't take those weights according to every source I can find.I had a look at technical data direct from Boeing regarding the max weights of the NG's and it lines up perfectly with the data from the COA manual.http://forums.avsim.net/user_files/115497.jpgThe data for the 600 is as follows for anyone interested:Max Taxi ---- 145,000Max Takeoff - 144,500Max Landing - 121,500Max ZFW ----- 114,500The reason that Vref speeds above the Mlw are included is that the 737 is capable of landing without significant structural damage in the normal fashion (i.e. no special touchdown procedures to reduce impact, it can handle about 600ft/min descent or in other words a no flare landing) at max takeoff weight. Of course it'll still get checked but the main struts won't buckle or anything like that, although you might need some new tyres (in saying that you'll probably have other things to worry about if you're forced into that kind of situation).Hope that helps a bit.David

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Hi Tim,Yes, you're probably correct. Different airlines have different MTW for their aircrafts, and may also depend on rather it's a passenger version or cargo. Ken.

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