delta2477a
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Post by delta2477a on Jan 4, 2010 11:30:50 GMT 9
I remember reading that the F-106 had leading-edge slots, are they covered by doors in flight to avoid a high-speed stall, are they opened automatically below a certain speed, or manually?
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Post by daoleguy A.J. Hoehn (deceased) on Jan 4, 2010 13:11:24 GMT 9
I recall the slots, but doubt they had doors. Guys correct me if I err, but the slot was specific to airflow in transonic and supersonic ranges for stability. The only doors (of sort) that moved to close off an area (and not fully) were the variable ramps located in the intakes.
AJ
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Jim Scanlon (deceased)
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Post by Jim Scanlon (deceased) on Jan 4, 2010 13:49:41 GMT 9
AJ is correct. The wing slots were permanent.
The Deuce had fences riveted on each wing for stability. When the Six was wind tunnel tested, it was determined that the fences would likely cause vibrations at high Mach numbers and that putting a gap in the wing, the slot, it would perform the same function as the fence with no structural problems.
I don't know who the engineer was who thought this up, but he saved a lot of grief for flight line guys.
The Deuce had wing covers and they had a sewed in section to cover the fence. You had to be careful in taking the cover off, or you could tear it on the fence.
The Six didn't have that problem, as the slot was in the leading edge of the wing and no problems when you had to use the cover.
The fence had to be inspected to make sure it wasn't bent, dented or scratched.
It was also hard on the ankles if you were on the wing and hit it.
So, the slot was a great idea. It was simple and it worked. No moving parts, no electronics, no nothing. Just a cut in each wing.
To the best my rememberer, that is the story on the slot.
Jim Too
:god_bless_usa
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Post by dude on Jan 4, 2010 14:41:21 GMT 9
 Pretty much agree, but I don't think the slots were specific to the transonic/supersonic. I think they were there more for wing normalization as it related to stall speeds and high angles of attack. In other words given the large surface area of the delta configuration, plus the fact that your surface controls were consolidated into elevons, if there was to be a wing stall, it was better to have it near the root of the wing for control than out near the end. Thus the reason the slot is located where it is. The Variable Ramps didn't become active until above mach. I think it was about 1.25M.
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Post by Jim on Jan 5, 2010 0:57:30 GMT 9
dude is rightabout the slats and the variramps, however a few of the first 6s did have fences but the leading edges were replaced prior to being turned over to the AF............. I don't recall where I saw pictures of some sixes with fence, hell, it is 50 plus years ago.......... Anyone ever change the flex jack shaft between the upper and lower ramp actuators?  ? The Old Sarge |
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Post by dude on Jan 5, 2010 4:09:49 GMT 9
dude is rightabout the slats and the variramps, however a few of the first 6s did have fences but the leading edges were replaced prior to being turned over to the AF............. I don't recall where I saw pictures of some sixes with fence, hell, it is 50 plus years ago.......... Anyone ever change the flex jack shaft between the upper and lower ramp actuators? ? The Old Sarge I think I remember reading somewhere here on the site that the early '56 pre-production models had fences, but all follow-on production aircraft had only slots. |
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Post by pat perry on Jan 5, 2010 6:13:34 GMT 9
Pretty much agree, but I don't think the slots were specific to the transonic/supersonic. I think they were there more for wing normalization as it related to stall speeds and high angles of attack. In other words given the large surface area of the delta configuration, plus the fact that your surface controls were consolidated into elevons, if there was to be a wing stall, it was better to have it near the root of the wing for control than out near the end. Thus the reason the slot is located where it is. The Variable Ramps didn't become active until above mach. I think it was about 1.25M. Hey dude, That sounds more logical to me. www.f-106deltadart.com/history.htm describes them as boundary layer fences which were replaced by slots. It does not tell their function theory. Also the same article describes lead edge flaps installed on a NASA B model test aircraft. en.wikipedia.org/wiki/Wing_fence describes the function of boundary layer fences which you described. I seem to remember being told, back in 66-68, the slots were vortex diffusers which cut down on the spinning air rolling off the wing tips (which increases drag). Diffusers was probably incorrect since they replaced boundary layer fences. BTW, I remember when I left the squadron we had some old vortex generators that fit on the canopy of the old TF-102 models (small rectangular plates about 1.5x2.0 inches) described on this page to prevent buffeting from the shape of the side by side cockpit www.vectorsite.net/avf102.htmlI am "aerodynamically challenged", so I figured, hummm, sometimes you "needs" a vortex and sometimes you don't.  Pat |
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Post by dude on Jan 5, 2010 10:53:23 GMT 9
Yeah Pat, I haven't heard that term (boundary layer) in a long time. I checked the links you had and they tell it a lot better than I could. I think (guess) the difference between a slot and a fence was the fence would act to impede/restrict airflow at a certain point, while a slot would provide a channel/slipstream for air to move through cleaner a that point. Both probably serving the same intent of changing the velocity mix at the leading edge like wiki pointed out. Anyway, its interesting to think about. I wonder how the experimental Six (F-107?) performed with the canards. By the way, the little bit of this I got actually came post-USAF from working with the F-4. I had noticed that in going from the D to the E model, they added slats to the leading edges. I remember asking a MSGT at George AFB if it was because they added the chin pod at the same time. He said no an gave me a little treatise on wing design; but in the end he indicated it had more to do with the increased emphasis on the air to ground role for the E/G's and the need for stablility in tight llow altitude manuevers. 
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delta2477a
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Post by delta2477a on Jan 6, 2010 7:44:38 GMT 9
1.) Does anybody have any picture, drawing, diagram, of what the slot looked like? (Assuming it's not classified)
2.) If the slot is opened at all speeds, how come it doesn't cause problems at transonic speed?
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Post by lindel on Jan 6, 2010 8:04:26 GMT 9
A good picture of the leading edge of the wing will show it. You should be able to find a shot of it at Pat's World home page. www.f-106deltadart.com A good pic is the NASA Chase Plane. The slot didn't really come into play until the bird was transsonic. As I understand it, the slot separated the outer section of the wing (as far as the airflow was concerned) and basically shortened the wing. |
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Post by jimpadgett on Jan 6, 2010 9:47:31 GMT 9
My understanding was that the gate (slot) was supposed to keep air from sliding off the wing thereby reducing lift and that the gate was as effective at this as the fence on the deuce. The original sixes (F-102Bs) had fences. The fences tore off during flight and the gate took the fences place. Have pictures somewhere of an early six with fences. Will try to find and post. Jim
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Post by dude on Jan 6, 2010 23:52:26 GMT 9
The slots were fixed, permanent elements to the wings that were always open. So physics dictates that they had to play a continuous role in wing dynamics at any airspeed, although it is reasonable to assume that those dynamics could vary under different airspeed and wing loading conditions. It would seem to me that if there was a particular issue about a Six wing in the transsonic region, then the appropriate fix would be the use of a slat, which is simply a slot that can be covered. In that way, you could control when the aerodynamics of the slot would be utilized, say from 0.9 mach through 1.1 mach. The only transsonic issues I do recall about the Six was a propensity to execute a "Dutch Roll" and oscillations that were typically nullified by the pitch and yaw dampers. :salute
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Post by jakesmart on Jan 9, 2010 6:38:17 GMT 9
I'm no "wing wizard", but it seems to me that the purpose of the slots on the 106 was to allow a high pressure "ridge" (or "air fence") to develop across the top of the wing at certain speeds and attitudes to mitigate a loss of lift due to air slippage off toward the wing tip. Wing fences could perform the same function but were they are also "permenant" drag devices, whereas slots, when properly sized, spaced and angled, would be most effective at speeds and attitudes when needed most. Deltas and high aspect airfoils seemed to be most affected by this slippage effect, thus the common presence of "winglets" at the tips of those long, slender wings ... I THINK ... MAYBE ... PERHAPS ... SOMETIMES ... or I could be all wrong.
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MOW
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Post by MOW on Jan 9, 2010 7:16:28 GMT 9
 You can see them here. One slot on each wing: a slit in the wing leading edge. They replaced the early fences and were basically a vortex generator that kept the air from sliding off the wing and any speed. A fence however also created drag due to the fact they stuck up into the airstream. Slots were found to be more efficient and rather innovative. Take that drag device off the wing and replace it with something build right into the wing... good stuff. |
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Post by MOW on Jan 9, 2010 7:18:55 GMT 9
Here is an actual wing fence on 560451 before it was replaced by slots
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Post by pat perry on Jan 9, 2010 8:10:56 GMT 9
Here is an actual wing fence on 560451 before it was replaced by slots Well, by golly. It was a vortex generator! Thanks Pat. Hey, I'm still wondering why these attachment pictures won't show in the "last 50 posts" view? Got any ideas Pat? Pat P.  |
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Post by MOW on Jan 9, 2010 8:50:01 GMT 9
Here is an actual wing fence on 560451 before it was replaced by slots Well, by golly. It was a vortex generator! Thanks Pat. Hey, I'm still wondering why these attachment pictures won't show in the "last 50 posts" view? Got any ideas Pat? Pat P. Yea, you need to open the thread to view those as they are hosted on this ite compared to links to other sites. It saves bandwidth and makes viewing the Last 50 faster to open and navigate through. |
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Post by Jim on Jan 9, 2010 10:29:13 GMT 9
Thanks for the nice pic of 27th's 031 in the arch hangar at Loring........
The Old Sarge
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Post by bear (Deceased) on Jan 9, 2010 11:49:37 GMT 9
I have a picture of 560459 painted red and gray with wing slats. It is print from Charles H. Hubbell tittle Thompson Trophy Speed Sweeps Past 1500 mph-1959 Go to best of hubbell.
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Post by pat perry on Jan 9, 2010 13:16:47 GMT 9
Well, by golly. It was a vortex generator! Thanks Pat. Hey, I'm still wondering why these attachment pictures won't show in the "last 50 posts" view? Got any ideas Pat? Pat P. Yea, you need to open the thread to view those as they are hosted on this ite compared to links to other sites. It saves bandwidth and makes viewing the Last 50 faster to open and navigate through. Hey Pat, That makes sense - we have the "need for speed". It takes a minute or two to navigate to to the post within the thread and work your way back to the "nifty 50" so I would recommend that posters using this file attachment feature let us know when a file is attached. example: Attached is a photo of earth I took while TDY to the moon in 1969. |
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Pretty much agree, but I don't think the slots were specific to the transonic/supersonic. I think they were there more for wing normalization as it related to stall speeds and high angles of attack. In other words given the large surface area of the delta configuration, plus the fact that your surface controls were consolidated into elevons, if there was to be a wing stall, it was better to have it near the root of the wing for control than out near the end. Thus the reason the slot is located where it is.
?
