Pitch trim with flaps down and gear down

[Sebastian]

Flaps and gear do produce a very impressing pitch down tendency. I need the full range of trim upwards to keep her controlable during approach.

I don`t think it is realistic that you have to set maximum elevator-trim upwards, or is this intended.

I can only compare with the high-praised RealAir Spit and trim effects are rather decent there.

[oakfloor]

Flaps and gear do produce a very impressing pitch down tendency. I need the full range of trim upwards to keep her controlable during approach.

I don`t think it is realistic that you have to set maximum elevator-trim upwards, or is this intended.

I can only compare with the high-praised RealAir Spit and trim effects are rather decent there.

How much power do you keep on final? my spit is a delight to land. And yes the realair spit is awsome

[CodyValkyrie]

Please note that this is a VERY early production spitfire. Also, I do not have the issue you speak of. I am not being a sympathizer, I just simply do not have that issue.

I would assume however that much trim would be needed as the plane slows since the flaps have no incremental settings. To boot, depending on fuel load, this may also cause an issue as it may shift the center of gravity. The P-40 shows this issue as well the moment you drop the gear.

[Sebastian]

You say you don`t need full trim? Then you have to pull the stick back during the approach. I always trim so that the plane flies the approach downwards on its own.

Nevertheless, I don`t think that in the real thing you would need the whole trim range just to keep the plane leveled between 90 - 100 knots.

[SD_Research]

You say you don`t need full trim? Then you have to pull the stick back during the approach. I always trim so that the plane flies the approach downwards on its own.

Nevertheless, I don`t think that in the real thing you would need the whole trim range just to keep the plane leveled between 90 - 100 knots.

The first problem is that final is not flown at 90-100 knots, that is much too fast and the pitch moment from the flaps at that speed will be very great. You should be crossing the runway threshold at 75 miles per hour, which is 65 knots IAS. You can pop the flaps at 90 mph (that's mph, not knots) and from that point the speed should quickly decrease to 75 mph IAS. You should be timing this so that from the point you pop the flaps to where you are over the fence only takes about 30 seconds.

Second, this plane is not a tubeliner or even a nice, stable B-17 in which you would fly a long final. It has to be flown all the time, it is inherently unstable and needs constant, small corrections to maintain its attitude. A nice, long approach where you can sip your coffee would cause the engine to overheat. You want to fly a nice, tight pattern and get the plane on the ground. It does not like being flown slowly.

The flaps are only going to be down for maybe 30-40 seconds if you fly a proper approach, maybe less if you are a good pilot. The plane is very easy to land once the flaps are popped down; you turn onto final, pop the flaps, wheel in a handful of nose-up trim (you've already trimmed for the gear being down at this poing), and fly the plane onto the runway. There is not time to set the plane up in a nice, long, stable, perfectly-trimmed final approach. It is a fighter plane and you fly it right to the last minute.

To to put in so much trim authority as to be able to wheel out all stick pressure for those 30 seconds of flight would mean making the trim so powerful that it would be dangerous and/or much too sensitive for the other 99.9 percent of the time you are flying.

I have not flown this plane in months and I was able to hop in it, take off, and do a nice pattern with a nice smooth wheel landing, no bounce or float, with no problems. I have a FFB joystick and the stick forces were minimal and I needed just under 6 degrees of trim. I think your issue is mainly your idea that the plane should be able to be trimmed out for a nice long final with no stick pressure, coupled with the very high approach speed you noted, but it's not that kind of plane. Put in some more stick time and fly it on the numbers and you should have no problems.

[Sebastian]

Thank you very much for the detailed answer. I understand now.

Being a virtual airliner pilot I am used to well trimmed planes on well established glidepathes...

[SD_Research]

Thank you very much for the detailed answer. I understand now.

Being a virtual airliner pilot I am used to well trimmed planes on well established glidepathes...

Indeed, makes sense. Just fly her like the fighter she is...

[cknoell]

I believe I have found the problem with having to trim so much on landing. The problem lies in the spit.air file. This was verified by looking at the P40B air file. The problem is at least in my airfile the 1101 Primary Aerodynamics heading for *Cm_df Pitch Moment - Flaps=0.050000. This value should be -0.050000 not positive except the value is too large. I found this out using Freimuth's air file editor for FSX. I changed the value to -0.030000 which seems much better and allows for an ~ 0 trim approach with gear and flaps down. I have also noticed that the air file is not nearly as complete as the FSX P-40B air file. If anyone does not know or have the utility to alter the air file, I will try to send them a copy of mine if there are not too many requests. My email address is [email protected]. It appears to me that the spit.air file needs more attention to detail. This may also be true of the other Solo aircraft that I have purchased.

Craig

[Lewis - A2A]

Our airfiles are created by a flight model specialist. Changing them un-does any promise that the aircraft will fly as they are stated to fly in the manuals. Including flying 'to the numbers'.

We strongly advise against any changes to make the aircraft fly how any idivdual thinks they should fly verses our tried and tested how they actually fly.

Re: incomplete air files,..
Remember the Spitfire was built originally for FS9 not FSX. FSX I believe allows more 'fun' to be had with air files and as with any developer our products evolve from one to the next so the latter ones of naturally further enhanced than the older models...

HOWEVER, we are currently revisiting some of the older models for our Accu-sim packs currently in production and various bits and bobs, no promises which bits, are being overhauled and new features added from a whole new code-base designed in house.

[CodyValkyrie]

Lewis is right. An indication of less in the air file does not necessarily mean anything, as the aircraft was originally built with FS9. Changing the structure of the air file is a very bad idea, as Lewis suggested, the guy that created them spent a lot of time ensuring that the plane flew by the numbers.

[Osram]

I changed the value to -0.030000 which seems much better and allows for an ~ 0 trim approach with gear and flaps down.

Is there a reason you think a Spitfire could be landed with almost zero trim (unless pulling back a lot, of course)?

Slow speed and gear out will AFAIK on any aircraft give you a nose down tendency.
Flaps used during landing can lead to nose up or down (or neutral). The Spitfires were not meant to increase lift, but to create drag, so they would add to the nose down tendency (IIRC the 109 is opposite).
So, I can not imagine there being no nose down effect, as all effects go in the same direction.
This meshes with BoBII, where you also have to trim if you want to make a nice landing. Its FM was praised by a Spitfire pilot.