XPFRs B17

[arno54]

There is definitely nothing wrong with your comments, which are perfectly honest, i felt not offended at all. I just wanted to explain why such a choice was done (and don't forget I'm french, my english is crappy so you may read intentions in my sentences that I didn't intended to put into them).

Back to the subject ! 

Yes, the exterior lacks a little bit for polys and texture spatial definition, Khamsin is the first to complain, but I "obliged" him to sacrifice this so that I can use the saved resources for other things.

Well, frankly, here we're splitting hairs : I guess it's not that bad. It's even very good. It could actually be even much better, but I don't agree with the cpu/gpu cost of that. Khamsin would, without any doubt, but, my godness ! I succeeded in stopping him killing my metbook, don't go and tell him his right, NOW!  :

The plane is so complex : it is a compromise... I hope you'll enjoy her anyway. You sure will. And again, there is no offense because you mentionned she's not perfect. She's not. But I really, in all non-modesty, think that Khamsin and I made her one of the very-best plane up to now  ;D Knowing we still can improve is, somehow, quite rewarding! 

Friendly

Arnaud

[eaglewing7]

I definitely will, and have enjoyed it.  It is a well modelled machine, and it likes to bite back when your not paying attention...

Guess I better contact Khamsin, regarding him cranking up the netbook killing polys, lol.

[Ben Russell]

You remind me of an ungrateful child picking olives and tomatoes out of a free feast.

[flyinhawaiian]

It is a well modelled machine, and it likes to bite back when your not paying attention...

Truth... It "killed" me earlier today when I pulled too much power off on short-final, foolishly thinking I had the runway made.

Anyone know what Vref is for the beast?

[arno54]

78 mph. make it 80 for v0, 95mph for v1, 105 short final, 95 mph touchdown. best climb 135. ;-)

[MaidenFan]

Wow, what a blast...

I finally got the engines to start and took a cruise around Oahu. I know what I will be doing this weekend!!!

[Nicola_M]

Sheesh, they weren't kidding about opening bomb doors first!  And putting distance between u and anything hard (like the ground).

I just dropped one when sat on the tarmac. End result:

[Nicola_M]

If it helps, I set up N for: Weapons/Weapons_select_down

And space to fire:  Weapons/Fire_Air_To_Ground

Anyone bombed anything yet? (apart from themselves, in my case). ;D

[khamsin]

I'm agree with the lack of external details of the Boeing B-17G. But I think I've done a correct job with only one 2k size texture for external model. It was our choice to give a fps-friendly aircraft for slow computers...

I think about an other version of this plane with high definition textures, normal & specular maps, but...

I must first convince Arno to exchange its ridiculous eepc for a real computer !  ;D

[UH-60 Blackhawk]

And to think, it will be FREE.

Really wish I saw that earlier, would've been on their site the moment I heard it was released.  Just downloaded, don't have time to (Try to) fly tonight.

[Airbus]

I would love to see this livery!

I think the B25 is way sexier!

[tegwilym]

I think I must be missing something with the brakes.  Says to "prime the brakes" but not sure where I do that.  I finally get all engines started and runining, high rpm, add manifold, release brakes, tailwheel locked (I start on the runway), and the plane rotates around to the right and goes backwards off the runway into the lake (I like to fly out of my real-life airport Renton, WA [RNT]).

I finally saved the situation where I can load the sim with engines started to save time and try again.

....backwards into the lake every time!

I'm really screwing up something, but not sure yet.  I think when I master this, I need to find a real B-17 and beg, bribe, and donate a kidney for some real stick time for my logbookg - I'll have a good idea how to fly this bird then!  :-)

Beautiful work on the plane, and thanks for giving it away free.

Tom

[Nicola_M]

Brake Primer is arrowed.  Push all the way in, and then back out. Then push in to about half way. Hope that helps.

[arno54]

I finally saved the situation where I can load the sim with engines started to save time and try again.

[...]

Beautiful work on the plane, and thanks for giving it away free.

Tom

This will NOT work. Actually, the feathering buttons write the acf "on-the-fly", because on the acf (inside PM), the props are fixed AND feathered. When you reload the plane you your engines running, the pitch is thus very HIGH, something like 89,9° ! As a result, the only thrust is is small one generated by the engine torque : to the right, and slighty backwards.

I guess your trouble as something to do with 1) wheels not braken 2) engines wrongly infeathered.

[FlorianR]

does anyone know where battery 2 is located? on the pilots control panel I only see batteries 1, 3, and 4 (all the way at the bottom).

[arno54]

There is no battery#2. Actually, batteries 1 2 & 3 are labelled 1 3 & 4. I don't really know why, that's just the way it is. Maybe it has something to do with the APU that is on bus 2.

[tegwilym]

This will NOT work. Actually, the feathering buttons write the acf "on-the-fly", because on the acf (inside PM), the props are fixed AND feathered. When you reload the plane you your engines running, the pitch is thus very HIGH, something like 89,9° ! As a result, the only thrust is is small one generated by the engine torque : to the right, and slighty backwards.

I guess your trouble as something to do with 1) wheels not braken 2) engines wrongly infeathered.

Ah! That must be what I'm doing wrong.  I swing right and move backwards.  I'll have to start over from the start with priming the brakes.  I did find that knob for that finally.  I did see it before, but then stupidly skipped over that part. RTFM for this plan for sure!

I cheated last night, set power and put the plane at 2,000 just to see how it flew.  Seems to fly nice, but I think my power was all screwed up.

Can I please get a type rating from the FAA after learning this sim?

Tom

[fatherjack]

This will NOT work. Actually, the feathering buttons write the acf "on-the-fly", because on the acf (inside PM), the props are fixed AND feathered. When you reload the plane you your engines running, the pitch is thus very HIGH, something like 89,9° ! As a result, the only thrust is is small one generated by the engine torque : to the right, and slighty backwards.

I guess your trouble as something to do with 1) wheels not braken 2) engines wrongly infeathered.

Ah! That must be what I'm doing wrong.  I swing right and move backwards.  I'll have to start over from the start with priming the brakes.  I did find that knob for that finally.  I did see it before, but then stupidly skipped over that part. RTFM for this plan for sure!

I cheated last night, set power and put the plane at 2,000 just to see how it flew.  Seems to fly nice, but I think my power was all screwed up.

Can I please get a type rating from the FAA after learning this sim?

Tom

Whereas the cockpit is well executed and the exterior model is passable, the acf of this B-17 is a disaster. I've had a look under the hood and it's a collection of misconceptions and interacting kludges. The aero in particular is useless. The attitude of the authors to problems with it is disappointing. The red letter RTFM notices would be bearable if the manual had anything useful to say. I have a B-17 Pilot's manual and it wouldn't help you either.

The turbo controller which they are so proud of, is a mess. Even with the waste gates jammed open, the power available from the engines at sea level should not be less than 1200hp.  

Having said that, the B-17 was no wonder-plane and performance should be fairly woeful.

[arno54]

- Attention to other readers/moderators : we know the guy. 

For some reason, he has a visceral hate against this plane and has spoiled us with endless hate emails (I eventually had to mark him as "spam").  I can't figure out why, as, as far as I know, he never flew her but has studied every bit of the file, making a very special inventory of what is wrong and how it should have been done. I'm always confused to see that some poeple are able to waste so much energy in negative action. (for instance, note that in this post, he mention faulty parts - why not? but no question nor suggestion or whatsoever : it's simply angry chinning)

Quite sad, actually.

[Nicola_M]

"Exterior model passable" !!?? It's got the right number of engines and wings, it looks like a B17, and the paintscheme is pretty amazing.

I'd like to see him put over 1200 hours into something and it come anywhere close to the B17.

Sad, you give something good for free and still you get moaned at.

[arno54]

Here are today's figures :

2200 downloads,

several hundreds of happy messages,

around 50 questions, mainly about piloting the plane rather than using the file,

and... well... our friend David "fatherjack".

The world is wrong, He Has The Truth. Well, we probably can live with that.  8)

[fatherjack]

"Exterior model passable" !!?? It's got the right number of engines and wings, it looks like a B17, and the paintscheme is pretty amazing.

I'd like to see him put over 1200 hours into something and it come anywhere close to the B17.

Sad, you give something good for free and still you get moaned at.

Yes, passable; good enough without being exceptional. But since you raise it, there are a number of minor to middling issues with it.

1. The engine locations are not correct. The outboard engines are too high with respect to the inboard ones. the outboard engines are actually not far enough outboard but that is visually insignificant.

2. The horizontal tailplane has dihedral which it should hot have. It is the wrong span too but that's not obvious.

3. The rear fuselage slopes up too much, making the fin a bit too short.

4. The mesh is not fine enough. Mesh density (within limits) has little impact on rendering performance and does not need to be scrimped on as much as many modelers think.

5. It's too shiny. A little thing but it shows up the coarse mesh too much.

I have put 1200 hours (and more) into object models and I know well how much work is involved.

My main criticism of the xpfr B-17 is of the aero design. The recent un-moderated personal attacks (and un-truths) illustrate the attitude of some of the authors to criticism. However since they have now invited me, here are my observations...

1. The fuselage has zero Cd. It needs this because the props are useless. Flying along with data showing you can see a L/D of 17 or 18 but you can still only manage 500 fpm at sea level.

2. The props have working angles from 89.9 to 90º and must be feathered to work, bypassing god knows what functionality in the sim. They are seriously oversized too.

3. The wings use the default NACA16 x-plane section. This is nothing like the required NACA 0018 to 0010 to spite the name similarities. They also only use two elements per mainplane, negating much of the clever programming by Austin. Multi-engined aircraft should use plenty of elements. Multi-element wings are necessary if you wish to see some of the normal aileron deficiencies at low speeds with a bit of slip.

4. Ailerons are massively oversized.

5. With no drag, this baby is not going to want to land, so they've added 60 square feet of flatplate area to the landing gear.

At this stage I stopped trying to see what was wrong with it. It is a pity because, as I mentioned above, the cockpit is well executed and the exterior model is passable.

One other problem area is the turbocharger control.

In the real B-17, each engine has a mechanical supercharger capable of boosting the engine to 1200hp at low altitude without any extra puff from the turbos. Before takeoff the crew set full throttle and adjust the turbos so as the engines are at no more than 42" of mercury. This turbo setting is used until the critical altitude is reached. Above this, throttles are left fully open and turbo control is used to adjust power.

This uses an innovative technique to access a dataref as a supplementary power control. A good idea and but not well enough executed, in my opinion, for a production release. The control effectively increases power without an increase in manifold pressure. Ultimately this may well prove to be very useful indeed as a fudge for non-plugin engine modeling. As a minimum, the manifold pressure gauges need an extra animation that factors in this new dataref. Without it, it is impossible to use it correctly.

[arno54]

---

PLEASE anyone.... Don't feed the troll. There's no way you'll be able to talk logically with him - I know, I tried.

Thx by advance.

---

[Tonka]

So somebody comes forward with useful constructive criticism, which includes useful details, and you mark them as spam and call them a troll?!

X-Plane is, or should be, about more than eye candy. Its about fidelity of the flight model, in both the core sim, and the aircraft that we make for it.

If this guy is correct, and you are using zero cd on the fuselage, the wrong aerofoils, incorrect tail dihedral and only using two elements of the wing, then i think he has some VERY valid points.

I appreciate that sometimes alterations, or tweaks have to be made to make things work in X-Plane, but to get the best out of the sim, if you want to model the performance of a particular aircraft accurately, some basic variables need to be correct to begin with. Variables such as fuselage drag, aerofoil section, and control surface and propeller dimensions should be accurate as far as is possible. There are also ways to get the best out of the sim, by taking advantage of the good parts. Multi wing elements can be included in this, especially with multi engine prop planes, with the engines mounted on the wing. All the extra wing elements could be used to improve the fidelity of the power on and power off stall speeds, as well as the aileron deficiencies fatherjack mentioned. Just think about the effect of all the prop wash on the wing of the b-17.

These are public forums, and everyone is entitled to their own opinion, even if it is not what you want to hear. Frankly, your attitude in the two posts i have quoted below, comes across as very rude. If you wanted to seriously model the B-17 and get it as accurate as possible, both in the flight model, and the 3d model, you would taking information like that posted by fatherjack and making notes of it all, and making alterations to your model to put things right, or politely explaining why you have done things the way you have and engaging in conversation with your critics to come to a compromise. Not one person, except perhaps Austin, knows everything about X-Plane, and we can ALL learn from others to make our models better, even the XPFR Team.

- Attention to other readers/moderators : we know the guy. 

For some reason, he has a visceral hate against this plane and has spoiled us with endless hate emails (I eventually had to mark him as "spam").   I can't figure out why, as, as far as I know, he never flew her but has studied every bit of the file, making a very special inventory of what is wrong and how it should have been done. I'm always confused to see that some poeple are able to waste so much energy in negative action. (for instance, note that in this post, he mention faulty parts - why not? but no question nor suggestion or whatsoever : it's simply angry chinning)

Quite sad, actually.

and

PLEASE anyone.... Don't feed the troll. There's no way you'll be able to talk logically with him - I know, I tried.

Thx by advance.

Here are today's figures :

2200 downloads,

several hundreds of happy messages,

around 50 questions, mainly about piloting the plane rather than using the file,

and... well... our friend David "fatherjack".

Several hundred of people who like what they see, and do not know any better when it comes to flight model accuracy perhaps?

The world is wrong, He Has The Truth. Well, we probably can live with that.  8)

Sorry to be the one to point this out to you, but if the errors listed are all correct, it is you and your team who is wrong, not the world.

I'd like to thank fatherjack for posting his comments. Its a great shame that Arno has been so closed off and rude about it. I for one like to know how accurate the flightmodel is on an aircraft, as i have no interest in flying pretty, yet aerodynamically fake aircraft. In my opinion, the X-Plane community needs more people to validate the flight-models on real word aircraft simulations. A review of an aircraft that only mentions the objects and textures, and ignores the FM is pretty useless for X-Plane, especially for an aircraft for which the details and specifics are available. - Arno, If you don't have the pilots manual from which fatherjack is making his observations, it might useful for you to get it, if you intend to alter your model to correct the realism issues mentioned above.

Lastly, Never judge a book by its cover. Number of downloads on the org is NOT a measure intelligence or accuracy. Just because you haven't seen a model created by somebody else, does not mean they have never done so.

[arno54]

@Tonka,

you make a lot of very good points indeed.

But you are wrong on the very main point.

X-Plane is, or should be, about more than eye candy. Its about fidelity of the flight model, in both the core sim, and the aircraft that we make for it.

I could not agree more. I won't take back all the points because I'm REALLY fed up with this, but in short, I really don't mind the name of the airfoils or the figures of the props in PM or whatever else. They are irrelevant here, it's just not the way the plane is done, the ONLY very thing that interests me is the behaviour of the plane in the sim. Anything else, is, from my point of view, definitely irrelevant.

Here is what I suggest : try the plane as a test-pilot, make any measurements about size, weight, climb rate, speeds, stall, ceiling with different payloads, lenght of runway used to take-off or land, turn rate, thickness, whatever you want. Compare to original charts, as we did the flight model AND the design from original docs - that's a rough 2000 pages to go through, for weeks of studying, (I can give charts to you, I do not wait for anyone to give ) compare the behaviour of the model in regard to the behaviour of the real thing as described in the orginal 1942's papers, in any aspect of the flight model you want. Tell me you find an error that exceeds 3% in anyway, but this will not occur.

If you are interested in knowing why on hell the props in PM are set to 89.9-90°, why it's declared as 600hp whereas it's supposed to be much more (or whatever other value that looks weird), I'll be very happy to explain why these choices, in an adult way of speaking. I'll be very happy to change my mind if you explain to me why I was wrong. I'm just not interested in tenths of posts/mails repeating "you're wrong because you're wrong". Because this, yes, IS indeed trolling.

One would like to understand and improve? okay, let's go for it, I'll take all the time that will be necessary.One thinks the plane is crappy? That's ok for me, really ! He just has to not use it. Or do a better one. Or whatever else, honestly, I don't give a cent about it.