B-S Model 75 - the visual model

i'd say, she's coming along nicely, Stephan.

i was able to take her out
for a little stroll, early this morning.
gosh, i even installed my joystick
after, i don't know how many years.

i found i had trouble getting
her to fly straight and level.
'tas, most likely, pilot error.
sounds like a good time
to put a trainer to work.
 
Stability

Hello Smilo,
Thanks for your comments about stability, or rather the lack of the same!

An old joystick, wow! I remember... I once used a fantastic FFB joystick on the serial port that I got at a flea market in 2001. It only works on an ancient Win98 Pentium I 266 MMX I have in a box... My present machine is one of the last to come with WinXP drivers, and all I can have is a FFB game-pad on a USB port. There are no game controllers for any other ports nowadays. That´s progress... backwards like the crabs.

Well, let´s see...
Pitch Stability: I´ll put a trim gauge into a corner on the panel. Although elevator trim does work without it, it will be a better reference. Depending on speed, slight elevator trim adjustments must be made, which I think is normal, but I can correct it if I´m wrong.
Bank Stability: Finally, I think I´ve found the .air file parameter to be adjusted to reduce engine torque effect, which seems to be the cause for the difficulty in maintaining level flight.

More, later!
Cheers,
Aleatorylamp
 
don't get me started on game controllers.
i could hijack this thread for weeks.
there was a time...
controllers were my main interest.
now, i mainly fly with the keyboard.
remember, i'm a bomber guy.
no fancy maneuvers in a bomber.
just accurate, straight and level flight.
most might find that boring,
but, for me, it's essential.

of course, pitch, bank and yaw
are governed by speed and torque.
at, say, 70% throttle,
i find one click of aileron trim
will cause her to bank left,
and one click the other way
will bank her to the right.
it's either bank slightly left
or bank slightly right.
there is no center.
my guess is the aileron trim sensitivity
needs to be backed off just a touch.
 
remember what i said a few posts back?
it was something about "pilot error".
yeah, well, never mind.
the trim sensitivities are just fine.
if i want her to fly more straight and level,
i can turn on the dang auto pilot.

sorry about that
 
Engine torque left bank/yaw tendency

Hello Smilo,
Not to be sorry by any means!
It bothers me too. I can´t find the way to trim the airplane to stop this annoying
and persistent left bank/yaw tendency. There should be a way, shouldn´t there?

Obviously engine torque is the culprit, because it stops when throttling back to idle.

I´ve tried adjusting aileron and rudder trim to zero, dividing it by 2, multiplying it by
10, changing plus to minus and minus to plus, but it doesn´t change a thing!

Neither does it seem to be affected by the Propeller Sluggishness parameter, with which
I thought it might be combined.

So, for the moment, we have to leave it as it is.

I increased pitch moments due to elevator and rudder a little, and reduced prop effect on
rudder, to see if control is a bit better, but it´s all a bit much of a muchness, really.

Anyway, we´ll see!
Cheers,
Aleatorylamp
 
am having an old man moment here.
as i recall, the trim conversation
has been had before.
i just can't remember where and
if a solution was ever reached.

after flying a bit yesterday,
i was able to adjust the trim
enough to attain satisfactory results.
needless to say, it takes patience
and constant vigilance to maintain
straight and level flight, but,
it can be done.
she's a trainer, after all.

needless to say, i haven't had a chance
to test the wep.
i am a bit curious about the results
of letting it run out
and the damage to be caused.
i can't help but wonder,
how the pilot will know
when he is close to catastrophe?
there is no wep indicator.
is he suppose to run a stop watch,
or is it just guess and by golly?
granted, i have a wep timer in my hud,
but, it is a digital counter.
i doubt such a thing was available
back in 1930s and 40s.

ps...i have lost the ap.
it didn't seem appropriate.
 
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To WEP or not to WEP, that is the question.

Hello Smilo,
Well, OK. It appears that the real plane had some torque effect issues too, which could be trimmed out to some extent, but not completely.

Regarding the use of WEP for 105% power:
In the .air file, the Maximum Manifold Pressure stays at the default 30 inches of mercury, and Boost Gain is set to 0.51, not Zero, and WEP type is defined (not zero).

This combination allows the smallest possible CFS1 power increase , which seems to be 5.5 %.
Looking at a boost gauge, a small Manifold Pressure change of about 1 inch of mercury at operating altitudes can be seen. Such a change would in any case be coherent with moving the throttle lever to full max.

Interestingly enough, lower entries for Max. Manifold Pressure and Boost Gain will yield ZERO extra power.

The problem with WEP, as you said too, is that it is impossible to predict when it times out.

That´s why I had the alternative idea to have the full 105% power available all the time, and a coloured scale marked on the Throttle bitmap, and a line on the throttle handle, tells you if you are in the "red" zone. Of course, no damage will be done if you stay there!

This way, compared to the real aircraft, the engine would have a permanent instead of a limited-time capacity for 105% performance. This also happens in CFS with the use of 100% full throttle, which should only be used for 5 minutes in reality.

Thus, there is a third alternative: No extr 5% power.
Do what most flying schools must have done, simply to block the throttle lever travel so it doesn´t give the extra 12 Hp.

As I am not much of a simmer and rather a builder, I don´t know what is best, so I keep asking the question.

At the moment, WEP Type 2 (Methanol-Alcohol injection) is implemented. I.e., after about 5 minutes, WEP is ruined, but the engine remains intact, keeping its rated 220 Hp at S.L.

Alternatively, implementing Type 3 WEP (WEP type supercharger), it cripples the engine to 50% power.

So we really have a wide choice:
1) No 105% power - keep it at 220 Hp.
2) 105% power to be used at the user´s discretion - no damage incurred.
3) 105% power available until it times out, losing the 5% power.
4) 105% power available until it times out, crippling the engine with a 50% loss of power.

So...
Cheers,
Aleatorylamp
 
...which in turn leads to a favorite cliché;
so many choices,
so little time.

i finally got around to testing the wep
and was a little disappointed
when the engine didn't crap out.
so it goes.
back to the choices.

i'm leaning toward the kiss option #1,
keep it simple stupid.
do i need to give my reasons?

as for the engine torque pull to the left,
(is it the P-Factor?)
for as long as i can remember,
i have desperately tried to taxi
in a straight line during takeoff.
of course, in the old days,
i would just firewall the throttle
and hope i could get into the air
before i'd run into something.
now, it's gently throttle up,
while giving a few kicks of right rudder.
careful, though, not too much,
or you'll over compensate.
 
Hello Smilo,
OK, thanks for the opinion! Yes, the more one thinks about it, the less worthwhile it seems to complicate issues for so little extra power anyway. Let´s do without it. It´s easy to take out by just de-activating WEP and Supercharger.

However, should you want to see how its overuse ruins the engine, just for fun, all you have to do is enter the value "3" into "Emergency Power Type" in Record #505 (Engine CFS/FS2000 Piston Engine), which at present has the value of "2". After about 5 minutes your engine turns into a clanking wreck!

As regards the leftward yaw, maybe in the old days on their grass strips, they could hardly tell if they were taxiing in a straight line anyway...

During take-off the effect is stronger than during normal flight, apparently because of the stronger propwash against the rudder. Then, with high angles of attack, it gets even worse when the "P" factor sets in, due to assymetrical effect caused by the difference in push between the upward and downward going blades.
I didn´t know any of this, so I had to look it up.

Incidentally, yesterday, I contacted my old friend Udo Entenmann, the texture specialist, and he replied today. With a bit of luck, we could get some high quality Stearman textures done by him. Let´s see how it goes.

What still bothers me a bit are the engine bleeds at the cylinders. That will be a difficult one to tackle.

Cheers,
Aleatorylamp
 
the "drift" is a fact of life and is something
pilots have to learn how to deal with.
obviously, they can, do and did, else,
they would never get off the ground.
i think the stearman was a great tool
for teaching how to do it.
remember, she's a touchy ground looper.

am glad to hear you got in touch
with Udo Entenmann.
it must be a huge relief to know someone
who has the texturing skills.
years ago, it was PJ Dunbar,
but, sadly, he left simming
and all his techniques went with him.

as for the visual engine bleed problem,
i'm sure you will continue to work on it
and come up with the best possible solution.
if it ends up with a few bleeds,
it ends up with a few bleeds.
so it goes...you gave it your best shot.
if a critic wants to dwell on it,
they can either dwell on it,
or do a better job themselves
and share the technique.
 
Ha ha!, Smilo!
Thanks a lot for your suggestions!

It reminds me of a reply I sent, years ago, to a wise-guy who insitently e-mailed
me, seemingly to praise my AF99 work, but in reality to criticize me for not using
GMax on my "wonderful oldies that should get the proper treatment they deserve".

I diplomatically explained that I liked using AF99, and had no time for more detailed
work, but he insisted on the subject, adding that in fact, Gmax was so easy to use
that even he, who was "only" a mechanical engineer, used it every day in the office
to design mechanical parts like gears or crankshafts.

The e-mails promptly ceased when I told him to design the aircraft with GMax himself,
that it would be much easier than gears or crankshafts, and that the 3-view drawings
for them were readily available on the Internet!

Anyway... As regards the Stearman being a touchy ground-looper, you can feel the
torque effect during take-off, which becomes weaker as you gain speed. My experiments
with 280 and 360 Hp engines for this aircraft, show that the effect gets even stronger.

I understand what you mean, that it will be difficult to maintain some kind of temperamental
instability on the ground and during take-off, and then try to have stable behaviour during
flight. I agree that it would be quite contradictory.

So, as it does actually become smoother when cruising or flying at full speed, I suppose
that this was your reasoning behind your comment after some testing, and that you had
in fact decided that it was best left as it is. OK, then!
Any additional suggestions or ideas will of course be very welcome.

For the moment I´m just making some very fine adjustments to eliminate the 5%
extra power in all its modalities, because its implementation was more of a niusance than a
benefit.

There would be another question, as regards mixture control: There is no gauge that only gives
throttle and mixture control - they all include propeller pitch control. Would there be a point
in using auto-mixture, and a gauge with only throttle control, or would this be a sacrilege?

Thanks in advance for your opinion!

P.S.
Incidentally, the performance data quoted for the 7-cyl Continental engine in the CAA
certificate is straight forward and quite easy to get right, unlike the 9-cyl Lycoming, whose
data is for the moment ambiguous and impossible to reconcile.
Thus, we´re using Continental engines only, unless or until the other one clears up.
Update:
I´m quite pleased to say, without going into any detail, that performance results for the
Continental engine are extremely close to specification - almost perfect. It´s unbelievable!
Quite the contrary of what was happening with the Lycoming engine some time ago...

Cheers,
Aleatorylamp
 
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many thanks for the chuckle.
for a moment, i thought the gmax guy,
you were referring to was me,
busily pushing ad2k on you.
you do see the similarity, right?

my line of thought
about keeping it simple
was, actually, based on early cfs experience.
it may be a gross generality,
but, let's just say, many didn't, or don't, care
about flight dynamics and engine torque.
what matters most is getting in the air,
going fast and shooting at stuff.
more's the better if one hits something
before one gets hit.
for me, it took spending time with hubbabubba
just flying around in multi player.
no shooting, just what he called "lazy flying",
before i started to appreciate the subtleties of the sim.
frankly, i don't know what people want or like anymore.
i know a lot of people look in on the cfs threads,
but, since they never comment,
i haven't a damned clue what they're thinking.
that's why i say, keep it simple
and please yourself.

ps...i guess i should make it perfectly clear,
if you want to talk about sacrilege,
you're talking to the wrong guy.
while i think it would be a cool skill to have,
i usually fly with auto mixture.
heck, i flew for years with auto rudder.
so, i'm the wrong one to ask.

although, i think it would be a cool thing
to have on the panel...just in case
someone wants to use it.
when i get a chance,
i'll look through my gauges
and see if i can help.
 
Hello Smilo,
It´s always interesting to have your point of view!

As regards my short story on the insistent GMax guy:
As is typical of me, I never think far enough to see possible lateral implications, and I see your point on the similitude with the AD2k issue. It was in no way intended of course, as you have noticed.
At any rate, your constant support and advice on the AD2k Electra project do make it very different!

About mixture control:
It seems that the real plane usually used full rich except for cruising,
so it would be quite easy to use, with a convenient gauge, of course.

Should you manage to find one, it would of course be wonderful, if it isn´t too much trouble.
If not, I´d say we could leave it at auto-mixture, because alternatively, doctoring up any existing gauges won´t help:

A) None of the default CFS1 gauge bitmaps helps, because the lever positions are different on the Stearman, i.e. throttle on the left and mixture closeby on the right.

B) Taking out the central pitch control lever from the default FSFS Conv. single-engined throttle quadrant, leaves a large ugly gap in the middle, and leaving it in, would be wrong.

OK, then. I already have some improvements - textures and .air file, so possibly I´ll post a WIP4 in the next few days.

Cheers,
Aleatorylamp
 
Work-in-Progress-4

Hello All, hello Smilo!
WIP-4! Now there´s quite a bit more new stuff on the Army Corps Stearman-75:

The airplane is now fully textured, except for wing- and landing-gear struts.
They will hopefully not be the definitive ones as I´ve been able to contact my texture specialist friend who has offered to help out here.

There is also an exhaust pipe and an air-intake (un-textured as yet), but now we have a student-pilot, and can charge for flight training so our company doesn´t go broke.

I´ve managed to stop the concavity bleeds at the top-wing cut-out by simplifying the curvature. The shape is not as good as before, but definitely still acceptable.

Here´s the model for those who wish to have a closer look-see and try out the new .air file with more correct performance.

Cheers,
Aleatorylamp
 

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A possible armed version too?

Good morning!
It occurs to me that as we are playing with CFS, perhaps an additional, fully armed, more powerful fighter-bomber version would also be in order, like those units exported to South America for the air forces of countries like Cuba, Argentina, Brazil and Perú.
Cheers,
Aleatorylamp
 
grabbed the WIP4, but, haven't tried it yet.

have been thinking about an armed version
and can't come up with a positive use for it.
all i can see it as, is fodder, sorry.

i guess, back in the old days of multi-player,
sometimes, we would all fly sopwith camels.
it was fun, but, i doubt anyone does that anymore.
 
Hello Smilo,
I don´t know much about flying in multiplayer - I never dared -
so I´m not very well informed as regards simmers´ flying preferences.

Then in fact, I was never good at R/C flying either - I just built own
designs and tried flying them with limited success. Also, as soon as the
R/C Club announced a competition, I´d stop building until it was over!

OK, we don´t want a Stearman to be cannon fodder!
So we´ll stick to trainers, if only just for the historical importance the
plane had for the formation of those thousands of pilots!

Here it´s the Spanish national Holiday,
so I´m taking it even easier than normal...

The new air-intake in the nose is a structure for the moment, as I am
saving the 2 free components I have left for an eventuality. If I don´t
need them, I´ll make a slightly better shaped component for it.

I hope you enjoy the progressing Stearman-75 model.
Do tell me whatever catches your attention!
Thanks in advance! (no hurry...)
Cheers,
Aleatorylamp
 
funny that you should mention youth rc experiences.
that opens a big box of memories...
mine was a fly by wire bf109.
i loved running the .049 engine on the bench.
but, when it came to taking the model out
and actually flying it....never happened.
i was too afraid of crashing the thing.
stupid fear of failure.

now, building a model from scratch
like the balsa guillows kits
is on my bucket list.
i would also like to build a solid wood model,
but, they're both just in the dream stage.
we shall see if that ever happens.
 
Navy Version

Hello Smilo,
I made two control-line balsa models with the famous .049 too - a Bristol Box kite and a kind of Helldiver. Needless to say, I very soon crashed them. Then, the R/C ones, I crashed them all the time - I hardly landed them... I remember one I flew 8 times in one afternoon, crashed it 8 times, and fixed it with epoxy resin 8 times...

Well... Here are some screenshots of a Navy Version in provisional textures.
I noticed that the Units I wanted to have in the desired colour schemes (Army and Navy), had registration numbers of units with metal Mc-Cauley propellers, so "181" is a provisional registration number!

Definite numbering will be Army: "28" and Navy: "69".

A piece of excellent news is that friend Udo Entenmann is already working on the textures!
Cheers,
Aleatorylamp
 

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