Ok Guys.. FDE Version 1.65 Alpha has been uploaded to the main directory of the file browser.. Download it and delete the current ile set your now using before installing these new files please.. Tom, you may want to just make a backup of your current files instead of deleting them ( just in case ) ..
Back to Anchorage, if not quite home yet! Sort of "one of those flights".
Will look at it later after getting home.
heh.. around the world in 80 hours, instead of days.. not very romantic but .. oh well.. hope you have a good flight home. watch out for those storms coming out of the Aleutians.. they're major mo-fo's
A few notes about CG: A speed stable aircraft will have it's trim vary a bit over the speed range. If it did not it would not be speed stable, dropping the nose with loss of airspeed and tending nose rise with increasing airspeed. CG changes with loading and often with fuel consumption. So there is no perfect CG that remains involiate.
With an aft CG longitudinal stability is reduced, and can become negative! Forward CG requires a large tail downforce and is very stable, perhaps so stable as to not reduce manuvering capibility, such as being able to execute a flair on landing. FS does not directly model tail force and CG stability, but applies modifiers to the wing moment.
So a plane with a CG such that it requires zero trim for takeoff or iniial climb will have to be trimmed for cruise, and on and on. It really is a matter of coming up with a CG that works for the range of possible loadings and stays within the handling envelope for various speeds and manuvers. Fighter aircraft with straight wings tend to have little CG movement, depending on location of droppables and ammunition and their location. Some fighters such as the P-51 that had aft fuselage tanks had quite a CG movement during flight. A good thing as the handling was quite poor with the initial aft CG. A transport aircraft, such as the DC2, that I worked on, required consultation of a load sheet to set the proper trim setting for takeoff, as loading over a long fuselage could result in widely varying CG's and trim values. By contrast the F4U had most of it's consumables and fuel near the CG and a takeoff set of trim settings could generally be specified.
So the question remains, where in the speed range do you desire the plane to be a zero trim?
Last edited by fliger747; August 25th, 2010 at 15:34. Reason: spel'n
My basic rule of thumb for zero trim is the cruise speed, or in this case slightly faster than cruise at 250 mph. That speed still lends a feeling of authority to the plane while covering a decent amount of ground without making a person fel like its taking forever to get somewhere..
I personally plan on making this my primary aircraft to fly in fsx, its just that good. So needless to say, i'm looking at all the things i would expect from my own personal aircraft..
Although i totally agree and concur with you regarding CGs, the driving impetus to finding the "exact" static CG is that when i reach a speed to maintain during a flight, i only want to set the trim once and be able to leave it alone.. to do that, the plane has to be perfectly balanced. I understand the difficulties involved in that. When i was building the p-36, i achieved it, as i did on the F-14 and Vulcan, but other planes have not been so agreeable, and the P-61 is one of the latter. Well get there though .. I have confidence in our skills and abilities..
A plane without the need to trim has no speed stability. Perhaps not too imporatant in FS as we have generally no real speed feedback feel through the controls. We manuver visually with regard to view and insturments, whereas much of the manual flight of aircraft is through the feel of the aircraft interfacing with desired speed and flight path. Almost all of the plane I have flown need a lot of trim adjustment through the various phases of flight. Many jets have considerable trim changes with thrust. This can be usefull as (for instance) one can make a very fine speed and path adjustments on say an ILS via thrust alone.
My Supercub needs a bunch of turns of the trim crank with speed change and flap extension. Speed stability is an important factor in the ablity to fly a very precise approach with good speed and path control. Especially important in carrier aircraft!
To test for speed stability, reduce the power without any trim or elevator inputs, does the nose fall and tend to keep the aircraft tending toward the initial trimmed speed? Negative speed stability would have the nose rise with power reduction (ignoring any thrust induced pitch).
In real (not FS) aircraft speed (and pitch) stability is largely determined by the relative positions of the CG and the CL. As the downforce on the tail varies with speed (no trimming change) the applied pitch moment changes. However if the CG is at the CL, the plane will have no pitch stability and almost no force required to effect very large pitch changes. At this point it becomes like ballancing a pencil on your finger. Aft of that the plane becomes dynamically unstable and without continuous inputs the plane will dynamically diverge into uncontrollable flight without intervention. Computer fly by wire systems can be used in fighters to fly an otherwise dynamically unflyable airframe and take advantage of manuverabilitues that result from such configurations.
The pilots mantra: Trim, trim, trim.....
FS makes things easier and we can get away with a lot.
But now see, when i wad flying a cherokee, we set the trim once for climbing, and then once again for cruising and after that just used the yoke to maintain even flight.. With many planes in FS, even with a yoke more sensitive than a mama's boy, you gotta trim every three seconds or so, even if your speed remains the same.. Thats what i would like to avoid.. i dont mind the idea of trimming every few minutes, thats just realistic, but every three seconds is a bit over the top..
As it sits, i'm trimming out the P-61 at a rate of about once every two minutes, which is plenty fine in my opinion.. Its an exceptionally enjoyable aircraft to fly.. The pitch moment may be a little low, but nothing serious.. Its just very sensitive which i would expect in a combat aircraft anyway..
Due to the vagaries of Dialup I lost contact wit the TS server, but did download the new flight model.
Definetly a hoot to fly and getting down to a matter of interpretation. I can tell from the contact points we are dealing with different, but not that different visual models. I noticed the comment about the video, which was fun to view, that as you stated earlier the visual components are still being worked on. Mine, the old one does have all the working animations and the textures are on the fuselage.
Slowly the project comes together, I hope that with all the give and take that the folks will get a better understanding of the process of these things coming together, and of some of the workarounds necessary to deal with the way FS interprets the world.
It's big, heavy and sometimes a bit of a sled! However using it's energy it can be pretty awsome. I have been flying this around in the new Solomomns Island scenery, great fun!
We should try this in a fighter flyoff on line as part of our testing, might learn a few things!
Best wishes: T
well I'll tell you - this is a most interesting thread, very interesting with many different disciplines apparently coming into play including but not limited to, research, A&P knowledge, programming and a measure of artistic 'feel'
I am compelled to stay tuned
..enter, the Sandman...
The planes weight definately qualifies her as a sled. When i first saw that dive in the video ( the one directly from the side ) it made my heart skip. That plane diving at 350 mph is either the most impressive sight, or the scariest sight ive seen from anything. Its just sheer raw power. I love it .
And yes, most definately we should be flying this online. Of course, everyone watching will be seeing 400 mph cessna's but, oh well. We'll get there ..
I did a flight tonight from Bend to San fransico by way of Mt Shasta. I only used about 30% of my fuel with standard loadout, which seems about right to me.. Beautiful flight. she cruised easily at 21000.
Definitely stay tuned.. ..
It is by the interior work that is going on that much will be judged! I was involved in a minor way in the testing of a soon to be released commercial product (which will be great!) and they were luck enough to have on the team a real aviaonics technician who could verify the accuracy of all of the installed instruments. Of course this one is a much older aircraft with most of the instruments long gone, even form the warbird circuit.
Keep up the great work!
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