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13°:Aerial

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2017-11-20

V2.C MEASUREMENTS  and  STANDARDS See: Explanatory Notes

Propeller  Thrust  &  Associated  Matters

  Contraption1 (for Guido)

ARE  YOU  METRIC  or  IMPERIAL ?

 Metric

 Imperial

 US

 
1. Define Runway Using the Runway Library
Result Fields
Input Fields
Pre-Defined Data
Enter runway length
Choose a runway

Runway length

Standard units

 
0% 100% >>> that's a crash on take off....
 
2. Define Aircraft
Result  Fields
Input Fields
 
Aircraft Take-Off Speed
Enter data

Take Off Speed

(hidden)

Choose unit


Aircraft Weight
Enter aircraft weight

Weight : empty aircraft

(hidden)

Weight : fuel internal

(hidden)

Weight : payload

(hidden)

Computed result

Weight : take off (TOW)

Standard units


Aircraft Engine(s)
Enter engine data
Propeller Engine(s) Nbr of engines Engine power

Prop thrust

(hidden)

Jet Engine(s)

Jet  thrust

(hidden)

Rocket Engine(s)

Rocket thrust

(hidden)

Computed result

Combined thrust : SI

Combined thrust : metric

Combined thrust : imperial


COMPUTED RESULTS
GRAPH
Take Off Time

Take-Off : time to V1

 
Take Off : Runway Length

Runway length

Runway length

Runway length

Runway length


4.0. Propeller Efficiency
Enter data

A  propeller efficiency

Speed = still

B  propeller efficiency

Speed = take off

C  propeller efficiency

Speed = cruise

D  propeller efficiency

Speed = max

 
 Aircraft Library
Pre-Defined Data
 
Aircraft TO Speed
Choose aircraft

Standard units


Refine preset

(hidden)

(hidden)

(hidden)

Computed result
Constraint

  (TOW)

MTOW


Refine preset
 

Prop thrust

 

Jet thrust

 

Rocket thrust

Computed result

  Combined thrust

  Combined thrust

  Combined thrust


COMPUTED RESULTS
 
Take Off Time

Take-Off : time to V1

 
Runway Length

Runway length

Runway length

Runway length

Runway length


M
.

EXPLANATORY  NOTES

Introduction

In Atlantic Air Combat™, aircrafts are either propelled a piston or turboprop engine, a jet engine, a rocket engine or a combination thereof.

In order to handle a single propelling value (thrust), and for illustrative and verification purposes, the present tool developped to figure out the theoretical thrust offered by a propeller associated with a given engine.

 Calculation is based on existing (simplified) :
- Source/Reference 1 : (link...)
- Source/Reference 2 : (link...)

Besides allowing a guesstimate of compounded propelling energy the tool will allow the following functions :

Convert propelling power from "hp" to kW and to thrust, the latter expressed in different units
Given a defined aircraft weight and its alleged take-off speed, the necessary runway length and the time to V1

Warning

This tool is developped in the context of the building up of an arcarde type flight game (with elements of simulation).  Using this illustrative tool to prepare a flight plan with a real-life aircraft is likely to bring deadly trouble - don't do it.

How to use these tools

The tool is divided in four different fields :

Are you Metri or Imperial ?

Ticking the proper box will preset the various data fields in the chosen unit, but you'll remain free to change the reference unit for each input.

1. Define the runway

Just define the runway lenght you want to refer to, specifying its length.  Like in all subsequent fields, only numerals are accepted with a single dot for decimal.  All other entries will be rejected.  Example for one thousand :

1000 (correct)   1 000 (not correct)   1,000 (not correct)   1000.00 (correct)   1.000 (accepted but meaning 1 rather than 1000...)

When the aircraft is defined (see below), the graphic representation will indicated the take-off point on the runway, expressed in % of its length.   So, for an aircraft taking off in 500 meters on a 1000 metres runway, the take-off position will be at 50%

Using the Runway Library

The runway library is not ready

2. Define the aircraft

Fill the various data field boxes to build up the aircraft take-off weight and specify the number of engines and respective output.  The input fields are located in the center of the screen and data are automatically converted to a metric values.

Aircraft Weights Using the Aircraft Library
Aircraft empty weight

-

(the Aircraft Library is not ready)
Aircraft internal fuel load

Atlantic Air Combat™ is using a single mass value for fuel - see Measurements.  Any external fuel is part of the payload

in time, the tool wil retrieve data from each aircraft datasheet

Aircraft payload

Bombs or any weapons (internal or external), cargo, passengers, extra fuel (drop tanks, bomb bay fuel cells, etc).  Besides the obvous (8 x 500 lb bombs = 4000 lbs) Atlantic Air Combat™ will be using the following standard values :

- 200 lbs for a crew member
- 250 lbs for a passenger

 
Computed Value The various weights will automatically add up to the defined take-off weight  
 
Aircraft Engines  
Propeller dring engines

Either piston or turboprop engines - specify take-off power,the number of engines and the diameter of the propeller.  The tool will convert this combination of data into equivalent thrust (see Propeller Efficiency)

In AAC, "take-off power" for prop engines is either the  "extra power" (1++%) when available or "full/military power" (100%) when not

 
Jet engines

Either turbojet or turbofan engines - specify take-off thrust and the number of engines

In AAC, "take-off power" for jet engines is either the "full afterburner" (1++%) value when available or "full/military power" (100%) when not

 
Rocket engines

This item cover the potential use of RATOG for take-off or any other similar device

 
Computed Value The various engine outputs will convert into a combined equivalent thrust  
 
Aircraft Take Off Speed  
Speed in meter/second Specify the take-off speed in your favourite unit, the tool will convert it to the international standard value  
 
Computed Results  

The various values  will be computed into a calculated runway distance for take off and a time to reach the specified take-off speed

 
 
Propeller Efficiency  

Atlantic Air Combat™ uses a simplified propeller efficiency curve.  In order to bring the "take-off" values closer to the expectation, one may naturally modify the engine power or even the propeller (theoretical) diameter, but tinkering with the propeller efficiency curve will be another approach.  In order to observe results, either :

modify the "efficiency" and "speed" values or
move the reference points in the graph

 
 
-

Note for Guido :

  • Not totally happy with the layout but the basics are there

  • I kept the "are you ISO, ...;" idea, but it's sort of redundant with what I have done

  • FOR A MOMENT, FORGET THE AREA ON THE RIGHT :

  • the idea is that the "reader" enters the values as they are known to him (center) and it automatically shows in standard values on the left (let's call that a computed value as opposed to a computed result)

  • I used the symbol to indicate that it's a computed result in the sense of what's expected by the reader

  • multiple computed results is thus redundant with the 1st question (are you ISO, etc) but it offers the advantage to immediately offer the results in all known units (if one forgotten, to be added) to keep everybody happy

  • NOW ON THE RIGHT SIDE

  • It's essentially the same as on the left, but based on libraries rather than free data input.
    > list of runways (always associated with its parent "airport")
    > list of aircrafts
    > internal fuel tankage to be taken from the DataSheets - fuel reduction would be done by increments.  A lot easier than a specific input to avoid the
       eternal issue with units.  Less accurate but thus a lot easier.  At this time, I choosed 10% increments, but the same would apply to 5% or even 1%
       increments with the latter allowing to retrieve a high level of accuracy.   Your opinion ?
        NB: I excluded any notion of external fuel tankage as we don't deal with range here - that will be for another tool...  (lol)
    >list of weapons set up : as discussed, each set up will get a name.   If the reader chooses the "F100E Super Sabre", only see the weapons setups
      for that particular aircraft show up
    > MTOW : a known value to be retrieved from the DataSheet as would the take-off speed (ie : both against a yellow backround in this draft

I haven't prepared the modifiable "propeller efficiency curve", but it should rest somewhere in the green area.   It should....   I mean, that's the only spot I see left at the time being !