New P3 Orion

aleatorylamp

aleatorylamp

Charter Member
Hi all, Hi Ivan!

I think that the complications that are arising during this job of converting the L-188 Electra into a P3 Orion, make an own thread necessary!

Apart from the fuselage-width, fin-height, tailplane-span and wingspan inaccuracies, now it turns out that the propeller diameter is also over a foot too small, and the distances between engines and fuselage are quite wrong too!

Comparing the measurments from the .pdf file to those of the large, detailed drawing that I thought was so good, it appears that this drawing is in effect the origin of all the misfortunes, which unfortunately the author of the original L-188 must have also used in good faith!

Anyway, not to worry. I´ve already corrected the fuselage from the "neck" backwards, and will be moving the fin upwards and extending the wing-tips and tailplanes outwards tomorrow.

So, with these modifications well underway, the cabin will then get a precise work-over, so that the "expression" derived from "forehead", windscreens and nose is the correct one. The wrong fuselage width/height may have been what was making this so difficult.

Anyhow, I´ll keep you posted as to how things develop.
Cheers,
Aleatorylamp
 
Hello Aleatorylamp,

Do you remember the post a while back when you stated that Length and Wing Span were pretty easy to find?
Seems like this original author didn't bother even checking those.

If you are going to do s much reworking, why not start from scratch? I have seen this model up close. It isn't really that complicated and you are likely to change EVERYTHING anyway. Why not just do one of your own?
The only really complicated parts on this aeroplane are the engines.

Remember the Me 109E Trop? I pretty much did the same thing with that project. By the time I was done, I had built or changed more pieces than were left untouched and it STILL did not satisfy my idea of a good project. To do it to good standards would have required changing ALL the parts at which point I would still owe credit to the original designer even though there was nothing left of the original project.

The only reason I did not do that was because I don't have all that much interest in a Me 109E. At some point, I will build a Me 109F/G/K series and if it is easy to convert back to the Me 109E, I might do that.

I believe the problem with this P-3 Orion is that like many other AFXs, it is basically just "Eyeball Scale".
Sounds like I am getting too arrogant again, but I do believe that measuring things out makes for a better model.

By the way, in looking at photographs, the Orion appears to have had two different tail heights though I have found no source that states exactly that.

- Ivan.
 
Eyeball scale

Hi Ivan,

Actually, the whole thing is a botched-up cock-up! So then, I´m arrogant too! And, it´s not only the people who build the models, but also the ones who draw the drawings!

I used to print the plan on paper, work out the scale, measure a part with a ruler and multiply it, noting it down on the plan by hand, but now I do it much quicker by drawing the scale onto the plan, adjusting pixels-to-the-foot, and then printing it out (or not). It´s easy to see a measurement by the lines on the scale. Of course it depends on how big the drawing itself is, in pixels.

At the moment I´m correcting the big drawing I found. The side view seems coherent with the correct data. Only the top and front views need adjusting. Here´s where the props, engine positions, fuselage width, tailplane-span and wingspan come in.

Apparently the right and left halves of the drawings are not consistent in themselves, one half being even more incorrect than the other! Once I´ve got the drawings right, I´ll transfer all my well-built parts into another Construction-List and like you said, make everything else anew to get a new model.

This way I won´t have to credit the original author - which is just as well, because if I were to mention him, then, in all justice, I´d have to include a walloping for the dimensional cock-ups!

So much for all that! Let´s see how it goes, then!
Cheers,
Aleatorylamp
 
Hi Ivan,
I have been correcting the detailed large drawing which was full of bugs, but now it seems like something usable. I incorporated as much data as I could from the .pdf document:

Fuselage width and height, Tailplane and Wing span, Engine positions relative to the fuselage, Propeller diameter and clearance to the ground, Wheelbase and tread, Fin height above ground, Fin height above MAD Boom, overall length.
Al these now seem to be correct. I have attached a copy of this heavily corrected drawing. I wonder....

There are, however, some things I haven´t found correct info on yet.
7 different side-view drawings, after graduating the scale on all of them to measure 116.8 ft in total length, are inconsistent in several positions:
Summarizing, these are the things that are not quite clear yet:

1) CoG : goes from 39 to 45 ft measured from the nose, generally around 40 ft.
2) Inner Spinner: goes from 24 to 31 ft from the nose, generally between 24 and 25.5 ft.
3) Outer Spinner: goes from 25 to 32.5 ft from the nose, generally between 25 and 26 ft.
4) Rudder Hinge: goes from 50.5 to 58.2 ft aft of the CoG, generally around 52 ft.
5) Rudder end: goes from 55 ft to 63.4 ft aft of CoG, generally between 57 and 59.
6) Nose-wheel: between 13 and 14.5 ft from the nose, generally around 14.3
7) Main Gear: between 41 and 44.7 ft from the nose, generally around 44.5

Would you perchance have a suggestion?
Cheers,
Aleatorylamp.

P.S. I´m trying to find a way that will allow the attached drawing to be blown up to be viewed, but it doesn´t seem to work like for other pictures. Maybe it´s too big?
 
This is why I was debating on doing a Design Study.... Because there is so MUCH information that building a model is easy.
Why are you using drawings when you have MUCH BETTER INFORMATION in the PDF????

1. CoG. Without any good weights and balances information, I would usually guess at about 25% of Mean Aerodynamic Chord.
Further down in the NASA document, you can find a table describing CoG limits and Gross Weight.
Allowable limits are 14.5 to 32% MAC, but 25% is always within the safe zone regardless of weight and is by eyeball, where the hardpoints are located.
25% MAC is 40.255 feet from the Nose.

4. Rudder Hinge Line is 92 feet 7.3inches from Nose

5. This is not a straightforward calculation but can be done from the geometric description of the Fin.

6. Nose Wheel is 13 feet 4 inches from Nose.

7. Main Wheels are 43 feet 0 inches from Nose.

I haven't actually looked very hard for a good drawing of the Orion yet. I pretty much quit when I found the NASA document.

- Ivan.
 
Positioning the extra points

Hi Ivan,
Thanks for your useful-as-always info!

I´d very much welcome a design study on this machine. A large, multi-engined prop-driven aeroplane as agile and fast as this one, could be very appealing - the only large US design of its type, with a very successful career after the initial teething problems that curbed production on the passenger-version.

I should have listed the doubtful aft positions in the side-view also as measured from the nose, that way it wouldn´t have been necessary to mention the CoG, which is already defined at 25% of the wing chord and lies within the range that normal pilot attention as per the .pdf document.

I only mentioned it because it shows that the dimensions fore and aft of it on many drawings vary considerably!

Anyway, with the restly information you have so kindly provided, the main issues are indeed clarified! Thank you very much!

Update: (I forgot to ask the obvious question):
In the .pdf document, some positions are indicated by mentioning 2 letters, F.S., W.L. or W.S. (perhaps Fuselage Station, Wing Level and Wing Station, but where exactly are they?), followed by a certain number.
E.g.:
Lower end of rudder: W.L. 207
Rudder hinge location F.S. 1216.3 (This is where you indicated the equiv. of 92.6 ft from the nose).
I can´t figure out how is this calculated. Perhaps you could expound...

Cheers,
Aleatorylamp
 
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Aircraft Stations

Hello Ivan,
OK, so I ´ve been reading about Aircraft Stations. Might as well educate myself... It was easier to find than I´d expected, and more difficult to understand why anyone would refer to distances this way.
WS= Wing Station
FS = Fuselage Station
WL = Water line (inherited from ships). Oh? Apparently is at zero on the ground... the ocean floor?
BL = Body line (running along the centerline, numbers increasing right and left. (logical)
The numbers following these letters are in inches (quite comprehensible).

The question still remains for the FS and WS. Where are these at Zero? That depends on the manufacturer. So, I looked in the .pdf to see:
I noticed a WL-150 line in a drawing, going from a little above the nose, horizontally backwards, and then, it says that the wing (chord line?) is at WL 85.5. ...measured from the ground, then.

Then, there´s a diagram on page 24, showing that the FS-zero is somewhere in front of the nose.
With other information given in feet, I suppose I can deduce where FS-0 is.

Update: Bingo! FS-0 is at 100 inches infront of the nose. At last!
WS seems to be the same as BL, so that´s left/right inches outwards from centreline.

I would have used a more normal method for an instruction manual, to say where things are.
I mean, nobody is going to stretch the plane if they want to use NASA´s investigatory services... Apparently this measurement system is done by the factory to prevent having to re-do the reference positions on possible stretchings of the aircraft.

So now it is clear!
"As clear as mud, but it covers the ground, and the confusion made me head go round..."
as Harry Belafonte sang in Carnegie Hall one day a long time ago, when we were young and beautiful, and quicker on the uptake.

Cheers,
Aleatorylamp
 
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NO!!!!!!

Hello Aleatorylamp,

You are correct in the notations:
FS = Fuselage Station
WS = Wing Station
WL = Water Line

You are correct that Wing Station is offset from the Aircraft Centerline
Water Line is "Sort Of" the ground line but is contradicted a bit in a couple drawings because the aeroplane does not sit level all the time.
Also, the CoG and Loaded Weight of the aeroplane to put the WL= 0 is unknown. At least I haven't found it yet.

Fuselage Station as stated on Page 8 o he Manual in Section 2.2.9 has the Nose at FS 105.

The offsets in feet were because I had already started a "Data Sheet" on the P-3 in converting some of the values.
Unfortunately, It was lost when I had to reboot my computer before I could save it.

Get used to picking an arbitrary reference point to locate things from. At least this one makes some sense and is consistent.
As for other strange ones:

The P-40 uses a vertical reference at the Joint between Top and Bottom Fuselage Halves. It is called the Fuselage Reference Line (FRL).
The P-40 also uses the Firewall as the Longitudinal Reference (Station 1)....
But in some manuals, the Longitudinal Reference is about halfway up the Spinner....

Some Aircraft use the extreme Nose as a reference but it would not be optimal in this case because sometimes the Orion had a more pointy Radome fitted.

The Hawker Hurricane uses the insertion point for the STARTER CRANK (!) as the "Datum Point"

The Firewall sounds like a pretty good reference point, but both the P-51 Mustang and the F4U Corsair had their firewalls moved around a bit with different engine installations.....

The manufacturer picked a reference point and generally if we want to use their manuals, we have to just get used to it.
It makes no sense for NASA to rewrite all the documentation for operating a SINGLE aircraft and also invalidate the training of other P-3 Orion pilots in operating THIS particular aircraft.
It gets better though..... After flipping through a bunch of Aircraft Manuals, you get an idea of what to look for. (Not to say that I am any kind of expert)

Regarding CoG being set at 25% MAC:
Look at Figure 2-5 on Page 14. Note that the CoG limits change with load.
Ideally for a Nose Wheel Aircraft, I would want the CoG to be a bit further forward but the location of the Wing makes that hard to justify even in the Virtual world if we want to have something that looks realistic

Please note that I commented on this on the original 3D model way before I found this manual. The problem with that model was that the Wings and Main Gear may not have been located correctly to make all the numbers work out....
Just from looking at a couple photographs, it is pretty obvious that the Nose Gear was way too far back.

On a related note, please observe that on this type of aeroplane, weights may move around a bit in flight. (The Weight of the Passengers is significant.)
When they move, the CoG changes....
One of the more interesting cases I have read about is about how changing CoG caused Martin B-26 Marauders to have failures of the Nose Gear.
Apparently, when Martin built the aircraft, there was a fair amount of equipment that needed to go with the aircraft to the operational sites.
They loaded it in a way to set the CoG correctly.
The problem was that when the equipment was removed, it caused a CoG shift which overloaded the Nose Gear which would sometimes break on landing.

- Ivan.
 
Ohhhh!!!!!

Thanks, Ivan, for your words of wisdom!

OK, so it is explained in "location of nose"... I didn´t know that it meant the outside front point on the nose - Somehow I mistook it for a space inside the nose for a radar, and it didn´t quite register...

The stories you mention on the topic with other planes makes it even more incongruent. It´s a free for all!
I would never have expected such an awkward and arbitrary measurement system.
Most probably it is meant to confuse spies. ...and modellers!
That´s why I call myself Aleatorylamp!

I think I´ll build a plane with a changing reference point, depending on the air temperature multiplied by the time of day. That´ll teach them!

So then, oh dear... it IS Nose point +105 inches for F.S. zero.
My psychiatrist will be happy with that.
When in Rome, do as the slaves do - sorry, the Romans...

Not to worry, it just adds to the fun. When you know, you know!
Cheers,
Aleatorylamp.
 
Not so easy...

Hi Ivan,

I´ve finally drawn up a nice 3-view drawing that has all the correct data from the .pdf´s aircraft stations and will be a reliable reference for a good model.

I think I´ll follow your hint and start a new build for this plane, because there are too many things which are too far out.

If it were only an inch or two out here and there, it would be bad enough, but I wouldn´t really mind, but here it is absolutely blatant, useless, preposterous and totally unacceptable: In some places it´s a couple of feet.

This model deserves the medal for inaccuracy:

Wings: over 1 ft too short
Tailplane: over 2 ft too short, 3.8 ft too far aft
Nose: over 2 ft too short
Fuselage: 0.7 ft too low, 1.4 ft too narrow
Fin: 3.4 ft too low, 3.6 ft too far aft
Nosewheel: 3 ft too far aft
Propellers and nacelles: 1.1 ft too far outward, at least 1 ft too far aft,
Propeller diameter: 1.5 ft too small

... and I thought it was coming along well, thinking that the original AFX were so good... Ha ha! "Pustekuchen", as the Germans would say: "Blow cake" - maybe you blow and the cake desintegrates... so much for the cake.

The adjustments are causing more confusion than benefit, so a clean table to start anew is in order here.
It´s not even worth saving what I´ve corrected, because that was the easy stuff - widening the fuselage with the straight component parts... If it were a ship it would have sunk.

I think I´ll take a rest... This is the first time I´ve scrapped a model.
Cheers,
Aleatorylamp
 
MOST Inaccurate?

Hello Aleatorylamp,

I never have tried to figure out what your name actually meant. Perhaps you wish to tell us?

There are other silly datum points on aircraft. I seem to remember the P-38 used the Tip of the Nacelle as Datum.
The problem is what would happen when something was added which lengthened the Nose???
This isn't just hypothetical, the Droop Snoots may have had longer noses and the Night Fighter almost certainly did.

I don't think this L-188 / P-3 is anywhere near the most inaccurate.
I think the Raiden I mentioned a while back wins that one.

Also, consider that your original model never claimed to be a P-3 Orion. It was a Lockheed L-188 Electra.
Dimensionally those two aircraft differed a bit.
The Wing Span on the L-188 is only 99 feet 0 inches while the Orion's is 99 feet 8 inches.
The Nose Cone is obviously different between the Electra and the Orion which might explain the 2 feet difference in length there.

Keep in mind that without all the stated dimensions in the NASA document neither of us would have had a good idea what the actual dimensions were. The NASA document didn't even exist until 2010 and although the data was certainly in other manuals, those may not have been publicly available.

We do what we can with the information available to us at the time and as we have discussed many times before, many folks out there are just not very good at building 3D models..... Such is the state of the "Art".

Anna Honey says I need to move my computer now.

- Ivan.
 
Errors lead to improvement (aleatorily?)

Hi Ivan,

Thanks indeed for your kind words on my inaccurate model! At least I know that someone else can get the medal for champion inaccuracies... Pity I can´t use the model as a paperweight.

Just before seeing your post I was thinking that without all this mess I (we) would never have learnt anything better, and for the moment, at least the positive result is that there are now new, completely exact, P3 Orion dimensions thanks to your find, and that I have been able to make my new accurate drawing.

The 1 ft wingspan difference to the P3 would have been no problem - basically fitting the outer wing component pieces... no big deal. Then, the 7 ft fore-fuselage shortening, which includes the differently shaped nose, would have been straight forward, so that after cutting, it would have been correct for the P3. But it wasn´t, because the wing was wrongly placed in the first place, and that is in reality the same, both for the P3 and the L-188. So, the nose ended up over 2 ft short and the tail assembly 3 ft too far back, even though the total fuselage length without MAD Boom was correct as per specifications in both cases.
But well... that´s what there is, and that´s what we have...

Now to your main question: "Aleatorylamp"

I remember writing a BASIC programme on the Spectrum + as a conversation programme exercise, based on a programme called Eliza, which was famous back then. It emmulated a psychoanalist treating a patient, and all it did was turn everything the patient said into questions with randomly different possibilities for their grammatical structure, and occasionally changed the subject. The public was impressed with Eliza - Wow!, computers can talk - even if only through screen and keyboard.

At that time, Stanley Kubrick´s Space Odyssey 2001 came out with HAL, the computer - so I called my version of Eliza, "HAL". I didn´t know then that "HAL" was the anagram for "IBM" (one letter forward in the alphabet per letter), and apparently Arthur C. Clarke didn´t know either.

So, I thought: Well, what does "HAL" stand for?
H? OK, just H=HAL! Now for the other two: A=Aleatory. Aleatory is "spanishized", meaning "random" (in Spanish, "aleatorio"), and finally, as Pixar had come out with its little animated desktop lamp logo, I thought, OK then, L=Lamp!

So it became "Hal Aleatory Lamp" - Aleatorylamp for short. (short?)...

This was, and still is, my opinion on computers... they are by no means an exact science, and can be unexpectedly aleatory when they want... but it´s not their fault, of course.

We will have a nice day, will we not indeed? - I like my now exact drawing of the P3 Orion!
Cheers,
Aleatorylamp
 
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Waterline

Hi Ivan,
Here I am with more questions...
The waterline concept is in theory clear to me, but I´m having difficulty in placing the wing at the correct height.

The root chord is 18.92 feet long, that presumably does not include the fairing, and the theoretical tip is 7.58 ft long, and the MAC is 14.06 ft long. So far, so good, but:

>>> Leading edge of MAC FS 545.9 (36.74 ft from nose) & WL 118.97 (9.91 ft from where?)
Location of .25 MAC FS 588.06 (40.225 ft from nose - no problem)
>>> Spanwise location - WS 254.3 (21.19 ft from where?)

I was wondering about the two lines indicated with >>>.

Update: The information is probably irrelevant, because having the fuselage height above ground at 16.8 ft and its width at 11.33 ft, the bottom part is at 5.47 ft above ground.
The waterline quotes, as you´ve mentioned, are sometimes a bit confusing!

Cheers,
Aleatorylamp
 
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Typing on iPad.

Read Section 4.1.1 on page 23.
Note there is a contradiction here for FS Datum Point.

- Ivan.
 
Hi Ivan,

Thank you for pointing out the contradictory information on the Fuselage Station for the Nose in Section 4, Payload Accommodation. I was still studying Section 2, Aircraft Dimensions, so I hadn´t progressed much further other than to look for diagrammes.

There is a saying: "When things go wrong, watch out! Chances are, they´ll get worse!", and the Spanish say: "There were only few of us, and Grandma had a baby."

With Fuselage Station Zero being either at 105, or at 100 infront of the nose, there is now a 50% chance of being 5 ft out instead of just 1 or 2, so inaccuracies may or may not get worse.

In my new, "corrected" drawing, at the moment, FS-0 is at 105, and I have the sensation that the fin is a bit too far forward, with the tail sting a bit too long. With FS-0 at 100, the fin would be 5 ft backwards, 2 ft further back than it was before, and it already seemed a bit too far back to start off with. The mind swirls.

Given the circumstances, I think I´ll just finish off the last AFX you so kindly shifted the CoG on. That model was already looking quite good, and you commented that it wasn´t as terribly inaccurate as I said, except perhaps for the nose gear, which is easy to correct anyway.

So, I´ll fix the nose gear, get the cabin shape right, and make some nice early-style military grey and white textures to finish up.

How about that for a plan?

Update: Here´s a screenshot, with the argument: "Maybe it´s not so bad after all..."
 Note: Textures are only provisional and ficticious...

Cheers,
Aleatorylamp
 

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Contradictions and Inaccuracies

Hello Aleatorylamp,

You have been building models as long as I have and have built a lot more subjects.
I will state it, but you probably already know from your own experience that there are ALWAYS inaccuracies and contradictions even with really good information.
I am still not convinced that I have really gotten all the bugs out of the P-40E Warhawk yet and I am about to start on converting it to a P-40F / K / N.
The Warhawk has already gone through its THIRD rebuild. Luckily this third one was only a minor adjustment of pieces.
Realistically though, I can't see the difference between the current 3D model and the last one.
Yes, I know there are differences, but you won't find them unless you find some means of measuring the wire frame.
So.... A foot difference in Wing Span or Length although it may be agonizing for us modelers is nothing for a really noticeable inaccuracy.
I say go for the correct shape. It is much more obvious.

After the last discussion, I was tempted to start a set of templates for the P-3 Orion. I had already started a Data Sheet to make checks easier than going through a large PDF.
When I commented that there were still inconsistencies, I was thinking that the Water Line / Waterline
references didn't quite agree overall....
I am not posting about those because it would just be a list of questions and I can't put them all together coherently without a set of reference templates and I don't really want to spend the time creating them.

Attached is a screenshot to show what I believe is the winner for inaccurate 3D Models.
The actual J2M3 Raiden is listed as 9.695 meters in length. This model is 6.500 meters in length.
Yes, both the drawing and model (from DPED) are scaled the same (1 pixel = 1 cm).
The differences are large enough that I didn't see the point of superimposing one image on top of the other.

Wouldn't you agree that the percentage of error is a bit large here?

- Ivan.
 

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Hello Ivan,

I surely laughed out loud when I saw the pictures of the Raiden after reading your post, and actually, what you are saying about shapes and sizes, is totally correct as far as inevitable small inaccuracies and the importance of correct shapes are concerned.

After putting the P3 Orion´s nose gear into position, I took a "walk around" the aeroplane, and with the exception of the cabin area that still needs re-working, everything else looks quite satisfactory, I would say.

It should do too, after all the work it has taken!

So there is more than enough reason to continue along these lines, especially as the aircraft itself, despite all the circumstances, still seems to be coming along quite nicely!

Also, as you seem to imply too, I don´t think any further analysis on the contradictory information as regards the Aircraft Stations will yield any additional benefit, and I think we can desist on that. It almost seems like the strange measurement system itself can lead to confusions that cause more problems than it solves.

Thanks for your moral, as well as technical support!
Cheers,
Aleatorylamp
 
Hello Aleatorylamp,

I am no longer sure that the actual diameter of the Fuselage is 11 feet 4 inches.
My current calculations from other parts of the drawings show quite a lot less.

- Ivan.
 
Useful information

Hello Ivan,

Interesting you should say that!
It seems more and more so, that it will be better as I thought yesterday, to leave the plane as it was when you shifted the CoG. When I had made a trial modification with 11 ft 4 in., I did have the impression that the fuselage was visually rather fat. Thank you very much for investigating further.

Incidentally, the contradictory information between FS-0 being at 105 and 100 is obviously in inches and not in feet, as I mistakenly typed yesterday without thinking, so the difference would obviously be 6 inches. Such a "correction" would suppose a 50% risk of being 0.5 ft more inaccurate, not 5 ft. Sorry!

Anyway, it is relieving that after all, that it isn´t as bad as we had feared. It seems that it is more correct as it is now - much better for an upload than possible worsenings.

Thanks again!
Cheers,
Aleatorylamp
 
Record breaking P3C Orion

Hi Ivan,

I think I´ve found a good theme plane for the P3-Orion. It was a famous record-setter described in

http://www.thisdayinaviation.com/tag/anti-submarine-warfare/.

It looks very similar to the one you had suggested - i.e. the one that was involved in a Chinese "incident" that never really was - but without the ridgeback and the radome on the lower fuselage infront of the wings.
The problem with this one one is that I´ve maxed out on components, and with 4.5% parts left over I only have enough parts to for a dome-cross-sectioned ridge-back, and not for the radome.

Anyway, the colour scheme in grey and white with a few numbers, marks and letters, and tail-art, I think could be quite appealing, and as it is a special case, this record-breaker (without special modifications to the effect) can be quite interesting.

Cheers,
Aleatorylamp
 
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