DH89 Rapide aircraft data required

Post by **RAF_Quantum** » 22 May 2006, 17:08

Manufacturer : De Havilland
Model : Rapide
ICAO Code : DH89
Max Passengers : 8
Market value (What would it cost to buy) : $80,000
Dry operating weight : 1330kgs
Max zero fuel wt : 2246kgs
Max take-off wt : 2494kgs
Cargo capacity (In pax config) : 178kgs
Normal/econ cruise speed : 106kts
Number of engines : 2

Post by **DaveB** » 22 May 2006, 22:12

Hi John,

I'm hitting some inconsistencies with the 89a's data matey.. well, between what is in the book and what is in the model. :roll: The best thing to do I suppose is go with the model so some of the data is straightforward.
I mentioned earlier that the 89a can accommodate up to 8 pax but the model is stn'd for 6, a pilot plus baggage.
Empty weight for the model is 1330kg
Max Gross weight is 2494kg (which is also MTOW)..
Max fuel is 248kg+/-
so.. max zero fuel should be 2246kg.
However.. with 1xpilot plus 6 pax plus 82kg for baggage/freight (eg.. if you load it to the default max) the takeoff weight is only 2199kg.. a shortfall of some 295kg. DG's pax weight of 77kg is pretty much around the industry norm so it will either have to be loaded up with all fat folk or find a way of squeezing in 295kg as baggage. 154kg could be bluffed off as 2 extra pax and this would leave 141kg.
I gotta say I'm not that struck on doing it this way so I'll have a look some more and hope that someone can come up with something a little more hard and fast in the meantime

Oh.. normal/eco cruise speed is 106kias :shock:

ATB

DaveB :tab:

Post by **RAF_Quantum** » 22 May 2006, 23:24

Hi Dave

The FlyNET briefing document shows a pax weight of 8.8t (tonnes) for 107 pax.

so if 8.8t was 8,751 kgs the pax wt would be 81.78kgs
if it was 8,849kgs the pax wt would be 82.7 kgs

My guess therefore is that FlyNET are using an average pax weight of 82kgs (107 x 82 = 8,774kgs or rounded to 8.8 t)

At the moment the FlyNET client prog doesn't change the weight in FS9 (you have to do it manually using the briefing document weights) so we could carry 8 passengers from a weight point of view. If the client prog ever does get changed so it reset our payload automatically, my guess is it would spread the weight evenly over available stations. I'll let you ponder that one - more pax = more pay for you

Alternatively, we could come up with revised stations for the .cfg so we can carry 8 legitimate pax.

Rgds

John

Post by **DaveB** » 23 May 2006, 00:40

Hiya John,

Rgr that. Never having seen what the Flynet client looks like or throws at you, I wasn't aware of how you can work around it. I've been on AIYR (HG691) many times over the years and she does regularly carry 8 pax as does AKIF so.. if the client prog will let this happen, then sobeit and all power to the people

So.. on the assumption that both me and the pax will be average Americans rather than average Brits.. pilot plus 8pax will be 738kg (as opposed to 621kg perviously listed). Max fuel remains max fuel at 248kg and empty weight remains at 1330kg. In order to meet the MTOW figure of 2494.. max pax plus max fuel leaves 178kg for baggage. This gives a (dirty) figure (or set of dirty figures) as..
Empty: 1330kg
Max Zero fuel: 2246kg
Max Cargo (max pax config): 178kg
MaxTOW: 2494kg
Max Pax: 8
which would seem to fill all the holes. I'm still not keen on the MTOW and MZF being the difference of the fuel (I know this sounds ballony) but.. it is possible to achieve. I test ran the Rapide this evening taking her up from 2199 to 2494 and did the best 2 'creamers' I've ever done although the handling is slightly odd

This was definately down to the fact that I'd left the pax loading as standard and bumped up the cargo/freight to achieve MTOW and gave me a main gear off first takeoff

With a revision in pax weight from 77 to 82.. this should not be so much of a problem

All we need now are a set of routes (and I know there were many!!)

Believe it or not.. I'm nervous :shock: ...

ATB

DaveB :tab:

Post by **RAF_Quantum** » 23 May 2006, 08:31

Hi Dave,

Thanks for that.

Would it be better to come up with some revised station positions to squeeze the pax in the right places? As I said, it's not an issue as such at the moment but if/when FlyNET changes the client so that it will load your aircraft weight through FSUIPC then we wouldn't want the handling to be odd. This is something to think about.

Routes........................please feel free to post when you are ready.

Rgds

John

Chris Trott · Post by **Chris Trott** » 23 May 2006, 14:05

Added to the database.

Post by **DaveB** » 23 May 2006, 18:29

Hi John,

I'm begining to think that a revision of stations is probably the best idea. Having spent the day trying to match the MTOW with what I can fit in, the effect on handling has been detrimental. While not impossible to fly, certain combinations have also pulled my cruise speed down to 102kts (not a great deal from 106 but at these speeds.. 4kts is the difference behind day and night)!! :roll:
I've been able to make some of the weight up by increasing the empty weight. THe model as standard is 1330kg/2926lbs but everywhere I look gives a tare weight as 3276lbs.. a difference of 350lb. This increase hasn't been too bad and the handling remains reasonably neutral (speed is up to 103kts too!)

Thus far.. the increase in Tare weight and making the pilot 82kg plus 6x82kg for pax and 164kg as baggage (simulating 2xpax).. the end result isn't too bad. However, this leaves a shortfall in MTOW (although not particularly large) but.. to make the difference up makes her too tail heavy to be comfortable.

Right.. gotta go now. Will see if something useful pop's into my fried brain this evening

ATB

DaveB :tab:

Post by **DaveB** » 25 May 2006, 01:04

John.. a quickie if I may,

Having spent a little over 2 days toiling over the 89a's model performance against real world data, I have thrown what changes I have made and what I've learned at Brian Withers who.. in the space of a few short hours has provided me with a workable 8-seater Rapide which is much closer to the numbers and is still 'flyable'

When I've converted the lbs back to kg's, I'll post the changes that need to be made to the Flynet database and when appropriate.. make the revised aircraft.cfg available here

ATB

DaveB :tab:

Post by **DaveB** » 28 May 2006, 00:47

:redface: :redface:

Blimey.. forgot about the revision.

OK..
Empty Weight is up to XXXX
MaxZF to XXXX
Cargo down to XXXX

I'm not sure John if Cargo in pax config is viable as a payload of 738kg (82kg per bod) is already assuming pax+baggage. There are still a lot of 'unkonwn's' so this is a compromise of 'best known' data but.. you gotta start somewhere

[edit] Hang fire on the changes to this Chris..

ATB

DaveB :tab:

Post by **RAF_Quantum** » 28 May 2006, 10:01

Hi Dave,

The cargo weight is a figure that we can use to 'fill up' with less than a full pax load. So, for example, if the pax figs were less that eight what is the max compartment weight for the cargo? At some point you meet the max comp weight so regardless of pax numbers, even nil, there is a maximum weight. The zero fuel weight will make sure we don't get overloaded. The 'in pax config' means we don't rip out seats to make room for cargo like in a combi aircraft.

Rgds

John