Author Topic: Credit where credit is due.  (Read 1250 times)

Shacker

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« on: January 27, 2000, 11:53:00 PM »
Just got through wringing out the newest FM for the FORT.

Much better guys. The power and RPM settings while not exact are well within the ballpark and produce the requisite airspeeds in various phases of operation. Climb, descent, cruise etc.

Glad the flap pitch DOWN problem has been addressed as well. THe b-17 still needs a bit of tuning in this area though. It should want to pitch up on flap application. This action while not 'dramatic' is pronounced.

The slip roll coupling on the B-17 needs a bit of work. At cruise there is only a very slight tendency to roll left. It is there but it is not very noticable at all. There is even less of this tendency at higher speeds and with full loads. (slip roll coupling for those that don't know is the tendency of an aircraft to want to stay level or to roll back to nearly wings level from a bank when the controls are neutralized. This is a function of the dihedral of the wings as well as the aspect ratio)

She is still rather 'quick' in roll, pitch and yaw. The b-17 is a fairly easy airplane to fly but does not respond quickly to control inputs. You have to stay ahead of the curve. She does not require a lot of muscle to make her perform just some prior planning.  The aircraft is not 'agile' but is responsive.

 

Offline Sunchaser

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« Reply #1 on: January 28, 2000, 12:12:00 AM »
Thanks Shacker, and here is another test conducted tonight by Terror as Pilot and Me as gunner.
"The Mighty Eighth War Manual"
by Roger A, Freeman states that the Service Ceiling is 37,500 feet.

Terror was able to get her to 37,600 ft. but that was all and the plane just would not go higher.

She would just stall out and nose would drop.

He tried several times.
Fuel was very low as we had just wasted Rooks HQ (almost sorry, Rooks.)and were almost home doing the test.

We were wondering about high altitude handling though, how do you think that is modelled?

It was fairly stable but the only comparison I have is SDOE in which I got the B17 to 29, 700 feet but above 23k it flopped all over the sky and at 29.7K it ran out of fuel.

Also, glide characteristics.
 Was she a brick on no fuel and if not what is a reasonable expectation of how far she would glide from 25k to ground?

Thanks.

Offline Pyro

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« Reply #2 on: January 28, 2000, 03:19:00 AM »
Well since you put it that way, I'll take a look into those issues.



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Shacker

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« Reply #3 on: January 28, 2000, 03:23:00 AM »
Actually the atmospherics seem to be modled pretty well Chaser.

Plane should get sluggish and want to 'wallow' at altitudes approaching the service ceiling. I dunno about nosing over though they usually just get mushy as heck on the controls and refuse to go another inch higher.

 

Offline Sunchaser

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« Reply #4 on: January 28, 2000, 10:26:00 AM »
Thanks, do either of you guys ever sleep?

Shacker

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« Reply #5 on: February 08, 2000, 12:35:00 AM »
I do sometimes Chaser *g*

N E How. Just looked at the new release for the B-17. It 'seems' as though roll has been dampened just a bit. I could be wrong here though.  I'll need to look a bit harder at it.

If so it still needs a bit more dampening. She is not hard to roll but she is not quick in the roll axis. Let me see if I can explain.

If you want to make a turn to the left say at point A then at some distance before point A you will need to input the left roll to the yoke there will be a small delay between the input and the aircrafts response to that input. You will want to input more yoke than you really want bank angle and begin to 'roll out' of the bank in advance of the desired heading as well. Neither of these effects are dramatic but they are evident.

Pitch and roll axis are, likewise, still a bit too nimble.

Rotation/Lift off speed at full gross is about 115 MPH. However I am still not seeing her get airborne at that speed. It gets up to the correct speed in what seems to be about the right amount of time (I really have no clue how long the runways are so I can't say for sure).


I'll wring her out some more and see If I notice anything else that may need attention.

 

Offline Sunchaser

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« Reply #6 on: February 08, 2000, 02:31:00 PM »
Thanks Shacker.
I was wondering about the runways too.

 I can never get her up from them with a full load and 100% fuel.{lucky some fields are on hilltops.}

I know full fuel is not required on this map but it will be so I fly on full when going long.

Another question, are the flaps supposed to retract at 150mph after you lower them and let your speed increase or should they take damage?

I do it a lot less now, but when lowering flaps at 120mph and allowing my descent speed to creep back over 150 the flaps retract, a real shock the first crash.


Offline Lephturn

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« Reply #7 on: February 08, 2000, 03:30:00 PM »
I might be way out of line here... but I wonder if "ground effect" might not be modelled yet?  I know it was introduced sometime in the 1.x series over at brand W back when HT and Pyro were running it.  If it's not implemented in AH yet it might explain the increased difficulty in taking off.  Just a thought.

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Offline Kieren

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« Reply #8 on: February 08, 2000, 03:53:00 PM »
Actually, I think ground effect is modeled. Example: had 1/2 a wing blown off, was falling out of control to earth. Managed to stabalize the roll component (almost). Figured if I could get near the ground upright I might be able to land it. Up to now it required speed to keep enough aileron authority to control roll.

Once near the ground, I gingerly leveled out. Roll forces diminished markedly, and I manage a very easy landing. I feel ground effect explains (in part) the seeming improvement in flight characteristics near the ground in this situation.

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Shacker

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« Reply #9 on: February 08, 2000, 10:28:00 PM »
HI Chaser!

The answer is rather complex.

No the fl;aps will not 'autoretract' on a real b-17.

If speed is increased over the long term with the flaps extended several things happen. First and foremost is you are overworking your power plants to maintain your desired airspeed.
Secondly damage to the flap retraction/extension mechanism can indeed result if airspeed is excessive.
Structural damage can indeed result if airspeed is excessive.
Flaps should not be deployed on a B-17 above 147 MPH indicated airspeed under ANY circumstances.
If you damage the extension/retraction mechanism the results can be catastrophic over the long-term. Short term results can be anything from they are now stick in the DOWN position to we now have one of em out there flapping in the breeze (it will eventually tear from the wing and may well take control lines, oil lines, fuel lines etc  along with it if the mechanism breaks free of the flap control arm)

So the correct answer is between nothing adverse happening and a full blown system failure that results in a crash.

Airspeed, wind conditions, structural integrity of the systems, wear and tear over prolonged use, etc etc all play into the equation at some point.

 

Offline Sunchaser

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« Reply #10 on: February 08, 2000, 11:04:00 PM »
You are quick today Shacker, thanks again.

So, my flaps bill here should equal or surpass my prop bill in SDOhEll I guess.

I am still going to spend the 30 bucks, maybe 60  while I wait cause I really like  flying around in those mountains and the sheep are very friendly.

Maddox, Looking Glass, Wayward, anybody{except perhaps Inertia}, please hurry?

Shacker

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« Reply #11 on: February 09, 2000, 07:05:00 PM »
I guess I gotta get ANOTHER dog???

 

Offline Sunchaser

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« Reply #12 on: February 09, 2000, 11:06:00 PM »
Better keep it away from the pups Shacker.