RAZBAM Harrier CoG Issue?

[ChristoffNY]

Hi all,

 

Attempting to get to the bottom of this issue again. My versions of the RAZBAM Harrier (Gr9 and AV-8) experience uncommanded pitching up as soon as any power is applied. The nose continues to pitch up until the aircraft stalls.

 

If the landing gear is retracted, the issue goes away and the aircraft becomes somewhat controlable. Is this a software issue, of a CoG issue that I'm missing? I've been using the stores management page to try full of fuel and empty but both times the same thing happens.

 

The FSX fuel and payload window shoes the CoG to be way forward however, right on the nose in fact?

 

Best regards to all,

 

ChristoffNY

[longbreak754]

Hi Christoff,

 

Its been a while since I have 'flown' either model but I do recall a number of things regarding getting it airborne.

 

1. Keys must be assigned (if not already done) to control the nozzles - the model uses default FSX Propeller assignments of Ctrl+F1 thru to Ctrl+F4. There are other essential key assignments that need to be made - IIRC all are explained in the first pages of the manual.

 

2. Aircraft weight - to do a VTOL or STOL takeoff fuel and/or weapons must be reduced. I always used the included Stores Management module as using the FSX Fuel and Payload manger can cause issues. For a VTOL or STOL type takeoff - IIRC - you get a warning on one of the MFD if it can't be performed, in the form of a status message.

 

3. Flaps - the flaps have an automated setting switch located in the left lower just below the main panel area. The switch has 3 positions and it selection will depend on the type of takeoff being performed.

 

4. Trim - IIRC all takeoffs are performed with trim set at 14 - again the manual details the various settings required for each type of takeoff.

 

5. Autopilot - called something else in the manual (AFC I believe) - must be off and only engaged once airborne.

[napamule2]

Razbam probably took the MS 747 FDEs and made changes to cfg values to match the Harrier specs. Nobody starts a FDE for a Harrier by putting the Ref Datum or the CoG on the nose. Nobody.

 

Since the pitch up goes away, when you retract the gear, that tells me that they had to incorpurate the RIDICULOUS '+14 Up' trim (might be a typo?) in the flight model for it (a 747) to achieve VTOL, but forgot to remove what they were using before to achieve the desired effect in the air file 1100 section (Flight Dynamics) 'gear pitch effect' which in the 747 air is '0.017100'. It should of been changed to '0.000000'. So don't change the Ref Datum (you'll be doomed) or the CofG. Find out where they messed up, and don't make sense, and change that. You could also try using '4.0' of trim (which would make more sense).

 

I don't have this payware harrier. But I work on FDEs and this smells like rotten cabbage, covering up rotten tomatos, to me.

Chuck B

Napamule

[longbreak754]

Having had chance to dig out my printed off copy of the manual I can give some clarification to my comment sin my original post, which were based on memory, regarding trim at item 4.

 

The manual states (on P46) the following.......

 

Pitch Carets (PC) are set at 14 for all takeoffs. This places the pitch carets at 6° of elevation with respect of the horizon bars in the V/STOL master Mode. This position

indicates the desired post􀀀takeoff placement of the Depressed Attitude Symbol (or Witches Hat). This takeoff attitude is the level flight equivalent of 14° AOA. Trim

for takeoff shall be 0° for both aileron and rudder. Shore based pitch trim shall be 2° Nose Down (ND). These trim settings are based upon rotation of the aircraft/nozzles

at the calculated rotation airspeed while the stick remains guarded at the trimmed position.

 

The PC setting is entered via a menu entry on one of the MFDs. The error is mine and not the result of the developer, as suggested by Chuck.......

 

@ Christoff - I will dig out the product, re-install and do a test flight to see if I get the issue you are experiencing. I will have some saved flights stashed away with various configs that I can also compare against to see how I had set things up prior to takeoff. FTR, looking back at my 'logbook' I see that I 'flew' both the AV-8 and GR-9 versions for 70+ 'flights' and about 140 'hours' and can't recall having the issues that you have experienced.

[ChristoffNY]

Hi all,

 

I'll have another play with it tonight and follow the steps outlined above and report back if it makes the issue go away.

 

Thanks to you both for your time and detailed responses.

 

Kind regards,

 

ChristoffNY

[scottb613]

Hi Folks,

 

You might enjoy seeing the new RAZBAM Harrier...

 

 

 

 

Regards,

Scott

 

 

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