Talk:Pelikan tail

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prior art?[edit]

See Fouga Magister. Perhaps Pelikan invented it for the USA. Potatoswatter (talk) 00:25, 2 May 2008 (UTC)[reply]

Pelikan tail is not exactly the same type of tail as vee-tail, look at slides #52, #56 and #60 from [1]. On #54 it shows two planes using the same tail as Fouga Magister plane, but on the next slide it says that it's an unproven design (aka, those designs are not the same design). See also photographies on page #2 of [2] --Enric Naval (talk) 15:47, 4 May 2008 (UTC)[reply]
I saw that, but without any references we can't tell if the middle section is a fundamental or a trivial change. Since #52 only has a vee tail in the background, possibly it just didn't register for them. All their verbal descriptions make it sound more like a vee tail. Potatoswatter (talk) 17:00, 4 May 2008 (UTC)[reply]
Uh... all diagrams and pictures show it as *not* a vee tail.... --Enric Naval (talk) 00:48, 5 May 2008 (UTC)[reply]
The control surfaces are identical. The only difference is that the bottom is truncated and the fuselage extends into the vee. Explicitly there isn't an elevator added between the "wings." Potatoswatter (talk) 01:00, 5 May 2008 (UTC)[reply]
Doh, so, it's different. The Boeing engineers analyzed it as a new untested design and finally dumped it because of the problems it had.[3] (pages 2 and 3) --Enric Naval (talk) 01:46, 5 May 2008 (UTC)[reply]
Except the V-tail also already found widespread disfavor because of its problems. There's probably a relationship between higher airframe stresses (mentioned at V-tail) and need for stronger hydraulic pumps (mentioned at your reference). Also, every design has to be treated as untested even if it has precedent. Potatoswatter (talk) 02:14, 5 May 2008 (UTC)[reply]
Uh, both the NOVA and the Air&Space magazine sources talk about of it as of a novel tail design. We are supossed to base the article on what the sources say, not on what we personally feel is more correct. The concers of stress have nothing to do with the weight problem. I think it has more to do with the fact that the Pelikan tail uses larger surfaces than the vee tail, as you can see on the plane pictures. --Enric Naval (talk) 03:08, 5 May 2008 (UTC)[reply]
For someone simply to claim their own design is novel doesn't seem NPOV to me, or even a reasonable argument. I highly doubt the magazine article reflects anything but the opinions of Lockheed engineers. It would be nice to actually find out something novel about it. Probably should ask over at WP:AVIATION. Also, your Air&Space source specifically said the weight problem came from the hydraulic pumps. Potatoswatter (talk) 03:42, 5 May 2008 (UTC)[reply]
I opened a thread at Wikipedia_talk:WikiProject_Aviation#Pelikan_tail_vs_V-tail. Notice that the article says "The bigger hydraulic pumps and cylinders needed to operate the larger surfaces would end up adding at least 200 pounds to the design." The V-tail cites no weight problems due to larger surfaces --Enric Naval (talk) 03:48, 5 May 2008 (UTC)[reply]

Prior art? ... yes and no[edit]

I’m commenting here in response to an RfC placed on the WP:AIR and WP:AVIATION talk pages. As an aerospace engineer who has actually worked with V-tail designs, I believe I can offer some assistance. First of all, is the Pelikan tail a V-tail? It can be argued either way, but I think it might best be described as “a variation on the V-tail” as there is more to it than a simple ‘V’ tail surface. The key differences are in how the Pelikan tail is structured and actuated. With a true V-tail, you have a single airfoil on each side of the fuselage; with a Pelikan tail, you have something that is more two airfoils joined at an angle on each side – when viewed from a perspective running down the centerline of the fuselage at the tail, it sort of looks like a hockey stick. The short plane is also itself part of the control surface; notionally, this would aid in pitch control, especially during slow-speed flight (such as when you’re approaching a carrier deck to land). The actuator is also canted at an angle to the perpendicular to the fuselage centerline, which permits more complex tail-fuselage geometry options. I’ve never seen aero performance data on the Pelikan tail, but I would not envy the flight control engineers the programming task it would pose.

To my mind, a Pelikan tail would add weight, complexity, and risk to a standard V-tail approach – and I’m not sure the asserted benefits in terms of weight savings (due to less tail planes and fewer “posts”) and signature reduction would outweigh the drawbacks – and that’s with respect to the traditional V-tail, which hasn’t proven popular for a variety of reasons. In fact, it is noteworthy that the Boeing X-32 design team originally went with a delta wing and V-tail combination instead, before the decision was taken to go with a more traditional wing and four-post empennage arrangement. The X-32 had a lot of innovations and the Pelikan concept may very well have been one that exceeded the technical and schedule risks – and development costs – of proving it.

In any case, we are left with an innovative concept that has never been introduced on a flying prototype, which leads us to the other main issue here: Is it sufficiently notable for its own article? Frankly, I wouldn’t be bent out of shape to find it treated separately or as a section in the V-tail article. I think what the editors debating here are actually more concerned about is whether its obscurity – compounded by its not having really been “proved” – means that it is non-notable. I’m not sure that’s an easy call. It’s not like we’re talking about obscure actors or sports figures or what-not; this is more part of the trial-and-error aspect of science and technology, and in that respect, failures – as well as non-successes – can be notable. Like flying wings and forward-swept wings, they might just need to await further advances in technology before they can prove themselves; even if they can’t be, it’s still useful knowledge to be aware of where the dead-ends are.

My strongest concern with this topic as an independent article is the weakness of the sources. With all due respect to the work of the students involved in the extant citations, I’d rather see more formal analyses published by seasoned scientists and engineers from the likes of NASA or Boeing that get into the strengths and weaknesses of the concept. While I see no problem with leaving this as an independent article, perhaps a compromise position worth discussing would be to place the material currently available into the V-tail article as a separate section pending discovery of better published sources. Askari Mark (Talk) 03:51, 6 May 2008 (UTC)[reply]

Thanks a ton!!! Don't suppose you'd consider creating that section... it seems like a such a specialist topic. By the way, you say the "short surfaces" are part of the controls. Would that be a separate elevator then? Because the current article specifies that there are only two independent controls. Potatoswatter (talk) 04:34, 6 May 2008 (UTC)[reply]
You're welcome! The short surfaces aren't separately actuated; they're part of a single "hockey-stick" control surface. That's what is so distinctive about the approach – and what makes codifying the flight control laws so exceptionally challenging. Even if the concept offered demonstrably superior performance with respect to other empennage design styles, there's a lot of work to be done to develop it. While I could certainly produce a write-up on the Pelikan tail, at present I have to admit I don't have better sources. I'm not sure to what extent McDD or Boeing has developed it and I cannot recall seeing anything published in the professional literature. That's one reason I hesitate to take a side in the disagreement here. I know some folks at Boeing who worked on the X-32, though, so I'll see if they can guide me to any open sources. Askari Mark (Talk) 20:00, 6 May 2008 (UTC)[reply]
Well, that's pretty impressive either way. You're way ahead of everyone else here... it looks like the V-tail article could see a lot of collateral development. Potatoswatter (talk) 23:29, 11 May 2008 (UTC)[reply]

pointless article[edit]

After reading this article the question remains: What is a Pelikan tail? The article doesn't even attempt to describe what it looks like. —Preceding unsigned comment added by 98.140.80.187 (talk) 11:54, 14 July 2008 (UTC)[reply]

I added an image. A description can be added, altought it will be very technical. --Enric Naval (talk) 19:46, 14 July 2008 (UTC)[reply]
where did the image go? this article is useless. 65.112.198.122 (talk) 21:08, 22 August 2009 (UTC)[reply]
Damn straight! I couldn't agree more. Where is a picture of the tail? How could it be that we don't even have a pencil drawing of the thing? I just want to know that what it looks like, just like every other person who goes to the trouble to look it up in an encyclopedia. If anyone knows, please draw us a picture and put it in the public domain. Thanks. - KitchM (talk) 03:28, 27 August 2009 (UTC)[reply]

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