SHP to thrust for FS9 Query

[hobby]

Can anyone please tell me how to convert SHP to thrust for a turboprop airliner?

Also how does one calculate torque for a twin engined turboprop?

[emfrat]

Hi Hobby -
I think you will find part of the answer here:
http://forums.jetcareers.com/cfi-corner ... rsion.html

ATB
MikeW

[Chris Trott]

Be careful with the conversion of SHP to thrust. In the FS9 Flight Dynamics engine, the thrust it is asking for is the jet thrust from the turbine's exhaust, not the thrust created by the prop. That is calculated dynamically based on what you put in for the prop diameter, number of blades, blade chord, prop weight, and prop MOI.

As for torque, you can't really calculate it. Remember the flight dynamics are torque PER ENGINE. Most engines have received a Type Certificate which can be gained here - http://www.airweb.faa.gov/Regulatory_an ... enFrameSet (in addition to telling you the jet thrust of the engine exhaust) and it usually lists the acceptable torque values for the engine.

If you don't find it there, try here - http://jet-engine.net/ Nate has a pretty comprehensive list with a lot of great information on most every turboprop and jet engine ever produced, including a lot of experimentals that never actually made it into production.

[hobby]

For Chris Trott:

Thank you for your help, first site very helpful. I have just downloaded zip from second site and will now study it in detail.

ATB, Hobby

[Chris Trott]

Out of curiosity, may we ask what aircraft this is in reference to?

[hobby]

PAD shorts 360.

Spent a couple of days trying to improve FDE. Mixed success so far.

[Chris Trott]

Ahh, okay. Here's the think with the PT-6 - torque is kinda irrelevant in the end since the engine is not directly driving the prop. As it's a "free turbine" it's kinda a wierd situation. If I remember correctly, the only difference between the PT-6 on the King Air 300 and on the 360 are temperatures, but there is a chart somewhere either on the Pratt & Whitney Canada site or in the Type Certificate that shows what the differences are. What I would suggest is copy and paste the AFG King Air engine information from both the AIR and CFG into the PAD 360 and then change only the values changed between that version of the PT-6 and the 360's installation. It will result in as close as you can reliably get.

[hobby]

Thanks Chris. I shall try that later today or tomorrow.

Main problem I now have, having brought the acft cfg to the point where the acft will carry the max real world fuel and cargo load (8300lbs = max cargo load) plus two pilots and one crew/loadmaster/flight attendant, together with the correct size wheels on the undercarriage, is that of getting the aircraft to 'unstick' cleanly. Once the main wheels are off the ground the acft seems to 'leap' into the air at an impossible angle before one can bring it under control to climb away clean at 700ft/min at 140Kts.

It is almost as if the acft had two ground footprints with u/c down footprint A= wheels apparently in contact with ground running along runway during t/o and footprint B acft leaves ground and mainwheels now appear on the screen to swing down on their suspension arms to the full u/c non load bearing position - the funny thing is it almost appears that somewhere there is a 'ghost' contact footprint still running along below the runeway surface. As one climbs away that 'ghost' footprint suddenly comes unstuck from the runway and the aircraft rears up at an astonishing angle before one can take corrective action!

Help invited because as Techy writes elsewhere the acft has a super shape.

[hobby]

Chris,

Hobby back again. The Shorts 360 has a five or sometimes six bladed prop so i should think that one would have to take that into account as well when dealing with the powerplant. I don't think that the Kingair was fitted with more than a four bladed prop.

[hobby]

Well I have to admit defeat on trying to improve the FDE for the above acft (cargo version). Please see my entry in CBFS forum section.