Post by Allan_Lowson on Oct 30, 2009 10:41:33 GMT -5
Maybe these guys? There stuff is freeware and they are happy to discuss improvements to their models. Recently they launched a SAAB 340 and when someone on Classic British Flightsim pointed out that the fuselage windows were too high or low they went back to the master model and reworked it to get it right. Not the work of a moment I am assured.
You're right, Allan, that's the one I was trying to say. I've installed a number of Twin Otters and quickly eliminated them, but I do have 2 from the group you mentined. I've only flown them very little so I can't give much info about them at this time. However, I don't fly them much because, again, at this point I can't put my finger on it, but they just don't fly correctly so to me I lose the enjoyment of the airplane. lr.
Post by Tom Goodrick on Oct 31, 2009 22:01:20 GMT -5
The model I have was originally from Premier Aircraft (Blaisdell and Small). I have the Blue Grass Airline paint job. The model was developed for FS2002 in 2003. I modifed the FD for use in FS2004 (FS9) and added a few corrections to improve performance and flight characteristics. I probably have notes from that period somewhere but not at hand.
As of this morning it flies nicely and requires some nose-down trim when the flaps are extended. The CH with a full house and 55% fuel (making the weight at MTOW) the CG is at 28.5%. This makes a difference. I didn't have a pilot's report on it. It does have big, powerful flaps.
I just checked the CG with just the crew on board and the CG is at 35.7%. Have not tried flying that. Too bad you don't remember those numbers. I just made a flight with this aft CG condition and it really requires nose-down trim now. I guess this agrees with your experience. But now its stall is a little more interesting. Maybe that setup you described with the wheel fully back depends on your trim, weight and CG.
This is what I can give now. I'll do one or two quick flights today or tomorrow for more info. So, this is Part 1. FS9; premieraircraft.com , Tamarik/Lab Air Wheeled, Windows XP Pro. I have two others from the Premier in livery of another virtual airline- no idea what the original model was, but these figures are essentialy the same.
1) Weight Errors. The enclosed description with the a/c lists the max weight as 12,000lbs. In FS, upper tool bar/airplane/fuel and load, the max weight is listed as 11,600 lbs. The real world max weight is 11,579 lbs.
2) Fuel Weight. The FS program gives a max fuel weight of 2,532 lbs of fuel. The real world a/c holds 2,475 lbs.
3) Fuel Distribution. FS list the fuel as a left and a right fuel tank (in the wings). The real a/c has a fore and aft tank in the bottom of the fuselage.
4) Basic Operating Weight. Is apparently too high. I distributed 14 pax, 2 pilots, added 1099.5 lbs fuel, and maybe 640 lbs baggage and was at max gross wgt- or a titch over. In the real a/c you can add 19 pax and 1000 lbs of fuel and baggage and be within the max gross weight.
5) Baggage. The default setting apparently puts 400lbs in the rear baggage compartment and 100 lbs in the nose. I'm sure the real baggage compartment holds more, maybe 600-800 lbs, but I don't remember, and I don't remember any baggage ever actually being loaded in the nose because there is virtually no room up there. The FS weight program shows the 2 compartments as the more rearward of parameters.
6) Fuel Shut-off Valves. On the Fire Panel, there are 2 fuel shutoff valves and 2 fire pull handles. Forget the fire pull handles as they are there for looks. The fuel shutoff valves are to shutoff fuel to the engine in case of engine fire (real a/c). In FS, these are set up to operate the fuel boost pumps, and they are automatically liked to the fuel lever on the overhead panel- why this fantasy was created is beyond me.
7) Fuel Levers. On the overhead panel, should operate as either ON or OFF. This is the simplest procedure I've come up with to at least get it as accurate as possible: Fuel lever OFF; note the fuel switches on the fire panel will go off. Very slowly move the fuel levers forward just until the fuel switches move to ON. Leave the levers in that position- as far to the rear as possible. The problem in FS is as you continue to move the levers forward, engine speed increases, which is not correct. Fuel levers do not control engine rpm in the Twin Otter.
8) Prop Torque. The relationship between Torque and prop rpm is totally incorrect. Take for example a torque setting from a low cruise to a high cruise setting. As you change the prop rpm, torque should change. In The FS program, torque remains fixed.
9) Prop Lever control is very poor.
10) The temps on the ITT gauge are way too high.
11) The beta system of prop control is totally absent. Probably an MSFS limitation.
12) Other minor errors. Common to all but a dozen or fewer a/c programs, not really important to many simmers. But here are a few: no DC Master Switch, no boosts pump switches, no bleed air switches, default MSFS radios.
13) Engine Sarting. Procedure is not correct, as is most other jet engines in FS. The correct procedure is to spool the engines, in this case as I remember, to 20%, then move the fuel lever to ON, the engine will ignite, and you must monitor ITT Temp to prevent a possible overtemp on start. MSFS starts the engines the same as piston engines, which would cause the engine to "melt off the wings" in the real world.
Flying Note: At this point I can only say that the flight dynamics is not at all good. Example, you should be able to set the flaps at 10 degrees, or 20 if you wish, props at 80%, add power and get airborne easily and climb. This program you can do it, maybe, but it is very difficult.
I'm not a programmer, but correcting the above problems would be a major advance in the operation of the Twin Otter. I suupose it would take some time to do so.