RFJ

A number of aerobatic designs in the reed period were reluctant to spin. In such cases it was necessary to provide additional up elevator throw to initiate a spin, this override movement being only available when wanting to start a spin - eg. normal up elevator control applied with the engine in slow throttle position.

The necessary override movement could be provided by mechanical linkage coming into effect only when full up elevator was applied in the slow throttle position; or by arranging that with this particular combination of control signals an additional switching circuit was brought into effect on the elevator servo board allowing the servo motor to override it's normal stop position and produce a longer than usual movement of the output arm. This entailed a special design of servo switching board incorporating override which, typically, gave about twice the normal up elevator movement under specific conditions.

....but I expect you knew all that already

Today of course we can use dual rate and/or loads of exponential. Back then we called it kick up elevator.

The MAN Taurus plan shows Ed's mechanical method but unfortunately the scan is a little small to show it clearly.

Ray

kingaltair

My Feedback: (4)

Only the Taurus airfoil is semi-symmetrical, (THIS WAS PROVEN WRONGEDITING 4-10-09). Ed was already moving to a symmetrical airfoil that started with the 'thick" winged Taurus-2 he took to the '63 W/C. I will take a detailed, critical look at it, but from what I remember, the thick wing looks FULLY symmetrical, just super-thick. The thin (striped) wing that we see on the pictures of the "Pusher", the "Japanese Taurus-2", and the final converted "Taurus-2" all apparently have the same wing, and that wing has the Bosch airfoil, (with the sharper L/E and widest point somewhat further back), that Ed learned about at the '63 W/C.

If there are differences in the way the Japanese T-2 and Final T-2 fly, it must be due to the differences in the fuselage. It would be interesting to see if the position of the wing was originally as far forward on the original T-2, or if he moved the wing 1" forward only later, when he adapted the T-2 fuselage to the thinner-wing. The T-2 nose is 1" less than all the other Taurus versions.

Duane

UStik

Not necessarily. What I find sort of weird is that you may well do with the semi-symmetrical airfoil if you only use a "real" 0-0-0 setup. Take away the engine down thrust, shim the wing down to -0.6 degrees incidence, and move the c/g 1" back to 5.75" - and you have a dead neutral airplane. (I tried with the 1" longer contest T1.) Spins and snaps obediently, lands like a charm. Still smooth and stable (7% static margin). Didn't Bruno Giezendanner fly even the 1971 W/C with a semi-symmetrical airfoil?

That airfoil pitching moment seems not a big problem, you just have an asymmetric configuration upright and inverted what is not good for negative snaps, for instance. But the problems we're talking about have to do with setup (decalage, engine thrust).

kingaltair

My Feedback: (4)

HUH AGAIN..........You lost me again, but don't bother trying to explain Not worth it to me

UStik

You're too fast for me, Duane!

I think the only symmetrical airfoil wing is the pusher wing. The Japan T2 is semi-symmetrical for sure because it's a standard T1 wing just built with straight trailing edge and more dihedral. The carrier wing may look symmetrical because it's so thick, but I assume it's semi unless proven otherwise. I suspect even the Simla wing was semi. BTW, the Japan T2 and the carrier and pusher wing should have different planforms.

To the T2 fuse, to set the wing 1" forward would have required to relocate the formers - that's what Cees thinks. Besides, you would see more than simple balsa strips because the whole cutout in the fuselage sides had to be moved forward.

RFJ

Marabu: NACA 2415 root - NACA 0018 tip.

Pedant time - I was once told never to refer to an airfoil as "semi-symmetrical" Either something is symmetrical or it isn't. Calling it half symmetrical doesn't make any sense. Apparently It should be described as bi convex

Ray

kingaltair

My Feedback: (4)

How can you tell the Japanese T-2 is semi-symetrical? Since the wing looks the same in the Pusher, Japanese T-2, and Final T-2, why wouldn't you conclude it is the same wing in all three? I will take a careful look at the thick wing tonight to check it, but I have already looked at it casually, and it looks symmetrical.

Look at the Simla airfoil on this picture...it doesn't look semi in the picture, and if somehow it is, it is very nearly symmetrical...so much so that I doubt it makes much of a difference. Remember the Simla was LAST in the design evolution; I find it difficult to believe that Ed would go back to anything that isn't symmetrical after everyone else in the world is going that way. The airfoil looks like the Bosch airfoil to me with a sharper L.E.

Duane

UStik

Ray, you are sooo right! Semi-symmetrical is somehow like semi-married, not possible?

It took some time for me to find a better expression: Let's call it cambered airfoil.

Duane, the NACA 24xx series means there is 2% of the chord length camber with maximum at 40% of chord. So if you have a 2422 with its 22% thickness you won't see the camber any longer. Hallmark of this airfoil series is the blunt nose. The Bosch airfoil is a NACA 0022-33, that is an uncambered airfoil modified in that the maximum thickness is more aft and the leading edge is not that blunt. That makes for a "better" stall behavior, what means it stalls at smaller angles of attack and with less drag. That's why Bosch could fly vertical snap rolls.

You can have a well spinning/snapping model with a blunt leading edge as well, only "at the cost" of more AOA and drag, and you have to achieve those greater AOAs. You can accomplish that with a less stable setup so the horizontal stab / elevator are more effective. That's all.

I'm sure the Japan T2 wing is cambered because it is described as a modified standard Top Flite Taurus. The carrier wing is just too thick to simply see if its cambered or not. At least the leading edge seems to be blunt what is not a sign of a Bosch airfoil. Besides, it existed before the 1963 W/C. The Simla wing has a blunt leading edge, to be seen in the big picture. What lets me believe it's a cambered airfoil is the small picture in the article where the bottom side is shown. It seems less convex than the upper side, if you compare them at the wing root. But it's hard to see and I'm all but sure. That's a main point when measuring the pictures.

RFJ

Description of the Simla from the rear cover of RCM August 1965.


Well, I know a few people whose relationship might be so described. A better analogy might be "semi pregnant"

Ray

Taurus Flyer

Gents

Picture 1 , The situation we did talk about in the past, the plane of Duane, we didn’t see a position of a former but part of the tank retainer.
Picture 2 , Part of a picture of Ed Kazmirski. Look at the position of the dowel and other remarkable points to coordinate, example the black dash on the white background.
Picture 3 , Same picture but now complete with three wing positions,
The wing on the picture is the thick wing with straight TE (blue) , the other positions of the Wester Taurus so original old first Contest Taurus (green) and the situation now (white). The numbers are the ratio’s of distances between the LE positions and canopy.
Picture 4 , The same positions projected in the on a pictures with the visible wing saddles,
Picture 5 , The copy of the Oldest Taurus on Earth, Wester Taurus.
In picture 5 you see also the original nearly horizontal banking of bottom line (Orange) the way it has to be when we put back all the deleted material.

This is a very important post because it also gives the positions of the old wings. so read it carefully.

Cees

kingaltair

My Feedback: (4)

I can't find the text, (if there is a picture in this thread that has it) that goes with the Japanese Taurus-2, ( is the whole article found somewhere in this thread?), but I would not take too literally the description "modified standard Top Flite Taurus". They are writing to the general public who are not studying every little thing in the detail we are here.

You are correct when you say the original Taurus-2 with the thick wing was before the Bosch airfoil. We have already concluded that Ed discovered the Bosch airfoil while at the '63 W/C, so I agree the airfoil on his T-2 at the time had a very blunt L.E. like the original, but that doesn't mean Ed was not experimenting with a form of symetrical airfoil by then. As promised, I'll take a careful look at it tonight, and report what I think I see.

Once Ed was exposed to the Bosch airfoil, it is reasonable to say he used that airfoil on everything he built after that time...this would include the Japanese T-2 if I am correct. Using logic, and the best deductive reasoning we can find, it makes more sense that this is the same wing in all these planes, (but we can disagree if we need to). Since the wing looks identical in the Pusher, Japanese T-2, and Final T-2, I believe it is the same wing...this is a safe assumption to make unless there is strong evidence to the contrary, and I don't see strong evidence.

Now, (thanks to Ray), that we know my assumption about the Simla having the Bosch airfoil is correct, it means we can scale up the airfoil to the right size, and re-create the Simla wing...couldn't we do that Burkhard??

Duane

UStik

Aha, you gave up your moved-former theory and didn't say a word. You should at least specify some dimensions, or do you want to say the wing leading edge was moved by 1"? The fuse must have been built with different proportions than standard later, maybe like the flatter Orion fuse. And how about the pilot/cockpit change? Anyway, don't tell you knew all from the beginning.

UStik

Yes we can, I specified the dimensions earlier. Still there are inconsistencies in the different articles and notes about Simla (different spans, weights). I'll look for my notes.

To the Japan T2: The wing is painted like the carrier wing, with curved stripes as all Tauruses. But the white stripe is tapered while it is not on the carrier wing. The pusher wing has no curves, only straight stripes. The Japan T2 wing has different planform, like standard Taurus but just swept.

Taurus Flyer

UStik

This is nonsense, bolt!



That 's why I post my message it does not fit my Taurus Construction and Flying Schedule.
The distances you can measure exactly on the plane of Duane, between canopy and wing position of the postion now. I cannot measure that.
It is also not interesting for my project
The ratio you can check with the picture of Ed, the carriër wing.

"The fuse must have been built with different proportions than standard later, maybe like the flatter Orion fuse. And how about the pilot/cockpit change? "

Ask Dennis Hunt.



"Anyway, don't tell you knew all from the beginning. "?

Page 3 post 68


"YES" UStik!

Cees

pimmnz

I think what Duane and UStik are trying to say is the T2 never had a standard Taurus wing section fitted to it. It went to Genk with the thick 'Carrier' wing, and was later modified to the Bosch symmetric (Non cambered, UStik!) wing. If you knew this all along, why has the Wester been fitted with a standard Taurus airfoil wing? Can you show us when this standard section wing was fitted?
Evan.

UStik

B...S... Cees! You tried to talk us into believing the former was moved. Now silence about that? Instead your usual "nonsense". Do you even know what I meant? If you're riddling like an oracle it's easy to be right after all. How about a precise reasoning, finally?

UStik

Duane, we can be pretty sure that the Simla had 95" or 96" wingspan. The ad (8.5 ft) should be wrong because the picture in just this ad comes out to 96". In the Veco ad Ed says 8 ft = 96 in, while the article says 95". Root and tip chord are 14" and 9" with the aileron width being the specified 1-3/4" (measured from the picture).

The weight given as 9.75 lb dry seems realistic while 11 lb with fuel seems too much (too much fuel). More realistic seems 10.25 lb.

I can tell you in advance that Simla flies slow and majestically because it has a low "relative" wing loading, despite the high absolute, nominal wing loading. Weak point is the small prop / little power. It's really the typical "bigger flies better" thing.

That's what I had from 7 weeks ago.

kingaltair

My Feedback: (4)

OK UStik. You have to look very hard to see any curvature in the paint scheme on posts 1130 and 1139, (both on p46), but I must admit, I think I can barely make it out if I squint just the right way. Maybe you have a better quality picture earlier on in the thread to look at, but the ones on page 46 don't bring out the paint scheme very well.

I was just about to concede the point, then I read the caption which said " ...the trailing edge is built straight...and the LEADING EDGE HAS BEEN GIVEN EXTRA RAKE" Sure enough, when you look closely at the leading edge, it is NOT the blunt standard Taurus airfoil, but appears to be the Bosch airfoil with the thickest section further back. Because under careful examination, the paint scheme appears different, it might be a different wing, but if it is, it has the same Bosch airfoil.

Another possibility is this wing was repainted later with the straight lines. There is evidence of repair on the L.E. of the present T-2 leading edge...who knows.

Duane

kingaltair

My Feedback: (4)

UStik....I don't know if you had the time yet to read my attachment on the left in post #1232. The article entitled "BIG STUFF" has information that answers, (or confirms some speculations) about some of these questions. In the second paragraph, the eye-witness who saw the Simla fly and wrote the article says the plane moves through the air with good speed, (or something to that effect). It describes its landing characteristics as "smooth", and not jerky, (sounds pretty good).

Up in the picture caption in the upper right hand corner the writer gives the wingspan as 95", so this "unknown" is starting to firm up some. This is how we eventually arrive at the truth, by comparing descriptions and seeing if they agree.

He also gives weights, (probably dry weights). Evan supplied this article for me some time ago. A very informative little bit of writing.

Duane

UStik

I just don't find that "extra rake" but I think it just means if you make the TE straight the LE gets more rake than before. The Japan wing can't be the carrier wing, if you mean that (I can't really get you). The fuse is standard Top Flite and you can see the wing is standard thickness. You can measure the root and tip chord lengths and they are standard as well (different from the pusher wing, but I admit I don't know the planform of the carrier wing). For my eye, the maximum thickness is at 30% chord.

I posted the picture somewhat darkened to see the paint scheme better. You clearly see the curve of the black part and may guess the curve of the red part.

And to the Simla, I did just that, compare these articles and notes and ads, and then I compiled it all to the figures I posted. Ah yes, I measured in the big picture.

kingaltair

My Feedback: (4)

Yes I certainly implied that in spite of the paint, they might be the same wing. Remember I owned the plane for weeks holding it my hand etc etc until I realized the T-2 had a symmetrical airfoil; then later on still that it had a "DIFFERENT" airfoil than the kit Taurus. Both of these facts are true, but I didn't see EITHER OF THEM right away. In all honesty, the overall thickness of the standard Taurus and the Bosch airfoil Taurus is very close if you're not looking for it. BTW..That wing still looks like a Bosch airfoil to me. [X(]

The caption says "extra rake", and I see "extra rake"....come on UStik, and be objective. I'm willing to admit you are right about the paint...printing it darker DOES help. Maybe you'll realize I'm right about the airfoil. If all else fails..."sleep on it", (another Americanism).

On another subject, a while back I mentioned that I might try to write an article about Ed and this thread for Model Aviation. Well today I heard back from them, and they have their article schedule booked far in advance, and just don't have room for a full article. That's a shame because I feel people would really enjoy something different...something about the early history of pattern.

At any rate, they asked me to write a small piece for the "In the Air" section which is kind of a "current events" area in the front of the magazine; there are usually two "mini-articles" per page, so it will only be a 200-300 words long, and may have one or two pictures. The little piece will deal ONLY with the AUCTION PURCHASE of Ed's 1963 W/C Taurus from his estate by the VR/CS, (Vintage R/C Society); how the funds were raised etc, and the upcoming dedication to the AMA Museum in September of this year.

If space for a full-sized article WOULD HAVE BEEN available, it would have been dedicated to honoring Ed and his accomplishments and innovations, (like one of the the first plug-in wings found in the Simla for example). His service in the promotion of R/C world-wide through his travels was what I wanted to emphasize. I WOULD NOT have written about which Taurus was first or was the oldest....or how the Taurus came to be. As can be demonstrated by 50 pages of thread, that process is too complicated to even BEGIN to try to explain to anyone else, plus we're still trying to figure it our ourselves.

Duane

Taurus Flyer

I didn't see the picture right, sorry.
With the Taurus you never can see the real position of the formers of LE and TE of the wing and especially not with a Contest Taurus after so many modifications.


If I know what you meant?

This you can do and is normally done, moved forward, when you want to mount a wing with a longer root / chord or a swept back wing for better direction stability or stall action, and if you not want to make the moment arm of the tail shorter!

This is also done after the wing with the straight TE is exanged with the swept back wings and that was what I did want to tell you. Post 1235 Picture 3 Distance 4
And when there is a former in the fuse, just as with glas fuses, then you can move them, no problem. Or maybe only the bottom part of that former.
The position of the wing is most important,and on second place the the position of the formers.
Modern plane have the formers near the wing, and the old plane have some distance between them.
Only the Taurus from Kingaltair does have the LE near the former and the dowel above the LE and that is strange????????????



Cees

UStik

Yes Cees, is a bit strange, but that was clear before. It's clear what you wanted to say with your picture in #1235. But if we assume the distance between the formers is only 12.5" (standard) and since we know the root chord of the standard wing is 11,7" including bellcrank tubes and that of the swept wing is 12" or even 12,2", then there is simply not enough room to shift the wing 1" only forward. It has to "grow" forward and backward. 1" forward would require moving the former, that's all.

UStik

Duane, I had a snooze and yes, we can't really make out the airfoil in the picture, particularly due to reflections around the wing root/saddle, and I didn't even try that. But I want to point out that there are two clues: (1) The text is about modifying a standard Top Flite kit, and you would use the die-cut 2419 ribs in this case. (2) In the picture, the wing has the standard chord lengths which are different from those of the pusher wing (different planform).

I wouldn't rely on visual impression because there is too much visual illusion with shapes like airplanes and airfoils. That's why I'd rely on these clues. And I thought you meant it's the carrier wing on the Japan T2, but that would be noticeably thicker. Maybe it's another wing with Bosch airfoil, but then why should Ed have used the pusher wing later, having already a Bosch wing that even had the real Taurus paint scheme?

But I don't intend to convince you. As Evan said, Ed "pops up" in Japan, so does this Taurus. Neither wing nor fuse are seen elsewhere. It's just another thing to ponder about, if there weren't the virtual testing and comparing in the simulator. There's just no point in comparing yet another swept Bosch wing, but there is a point in comparing a swept wing with more dihedral and shorter tail but all else unchanged. That was my rationale, to check what was said in the text and the picture being consistent.

The carrier wing still needs a thorough check, by the way. You could take your pusher wing airfoil template and (1) double-check the pusher wing by applying the template not only to the upper side (were it was made) but also to the lower side (should fit as well). Then (2) do the same with the carrier wing. It shouldn't fit on both sides but you'd see if the mis-fit (and airfoil) is symmetric. We should also know the thickness in inches.

As to the MA article, better not at all write an article about the stuff in this thread. After all, what we can offer is only ideas, indications, conclusions, something to ponder about and come to one's own conclusions. I don't think it's possible to wrap that up in an article, it has to live here in the forum.

kingaltair

My Feedback: (4)

Now for some hard facts rather than just guesses.

I had never taken a close look at the airfoil of the original "Carrier Wing"...it had never come up in the conversation. Upon closer look, the Carrier Wing is indeed SEMI-SYMMETRICAL . That's another one for you. If you draw a line through the middle of the L.E. and the T.E. and measure, the thickness of the tip rib yields 3/4" above the line and 1/2" below the line. If you look closely, it is easy to see the wing is not symmetrical. The thickness of the Carrier Wing at center is 2-1/2" thick. The maximum thickness of the Bosch T-2 wing is 2-1/8", and 2" exactly at each of the W-2 ribs.

I also measured the width of the opening of the wing bay of the Taurus-2....it measures 11-1/2."

Regarding the Japanese T-2, is there more text than just that small amount on post #1130? If there is, do you have the whole article you can scan, because I didn't understand the text so say anything about ED modifying a kit. If you look carefully, the text tells its readers what to do with THEIR KITS, including "adding more rake to the L.E." That means changing the airfoil of each rib in the kit somehow. When you stop and think about it, how could the kit builder "add more rake" without changing the whole airfoil. That doesn't seem well thought out on the part of the writer, who obviously observed that Ed's plane did not have a standard Taurus airfoli. Maybe he thought the builder could just sand the L.E. to a sharper point, not knowing the L.E. was pre-formed and couldn't be changed.

It seems very strange, (meaning impossible), to me that Ed would build a plane FOR HIMSELF, (after being exposed to the Bosch airfoil), that would have a semi-symmetrical STANDARD TAURUS KIT airfoil. Ed was convinced before that time that the Bosch airfoil was the way to go in the future. Regardless of what the text on that page says, the wing in that picture is NOT a standard Taurus wing. This may seem like a small point to labor over, but when we are talking about a picture of a plane that Ed built himself, it is important that we come to the proper conclusion about everything having to do with that model. Ed would never have taken a standard Taurus kit and modified the KIT ribs to make "MORE RAKE"...he would have built new ribs, and a new wing for his own model. Maybe Ed modified a fuselage while building it from a kit, we have no way of knowing.

It still makes no logical sense for Ed himself to build a plane in late 1963, or early 1964 with a semi-symmetrical wing.

About the proposed M.A. article, I think it's possible to summarize the high points of this thread into an article for people to get the flavor of everything we've discovered, but it looks like each brave soul will continue to have to "plow through" the whole thing if they want, and come to their own conclusions.

Duane

Duane