I'm not sure how I would that, I make my pics by taking line drawings and cutting them up and pasting them together.
I might be able to find some pics of the undersides of plane and draw where the points would be, will get back to you.
Japanese Drop tanks, and float planes, 1930-1945.
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I might be able to find some pics of the undersides of plane and draw where the points would be, will get back to you.
From this pic, it looks to me like the Rufe has three attachment points, and I'd be willing to bet they are not welded on, but simply bolted to hard points meant for easy to changing them out when needing replacing.
Hope this helps..the floats don't really help in the drawings, unfortunately.
Both these images can be found on the wiki for the Rufe.
Hope this helps..the floats don't really help in the drawings, unfortunately.
Both these images can be found on the wiki for the Rufe.
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OK I'm not sure if this what you wanted but we can make improvements later on.
The small black squares represent the hard points.
Here's a photo of the only single float floatplane I know of;
As you can see there are two very small floats on the wings.
I can make a similar pic, just let me know what plane you would like me to try it on.
That is a nice looking plane, shame they didn't try jettisoning floats earlier, as they may have gotten it working. The 14 cylinder, 1,850 hp motor with contra rotating props is like a dream come true, I wish they had made that into a torpedo bomber, lol.
I agree with what others have said, that this is of dubious utility. At best it seems too niche but I'll leave discussion of the tactics to those better versed. I'll rather address some of the engineering practicalities instead.
With an A6M2-N as the base aircraft, assuming no increases in weight from the modified float for fuel carriage, pumps and no structural reinforcement necessary from the increased weight, the 'Rufe' has a difference between gross weight and MTOW of 926lbs. That makes an allowance for only 154 US Gals, only 69 US Gallons or so above that already available from a standard A6M2 drop tank for a great penalty in drag.
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I get that increased fuel isn't the sole object and that operational flexibility is also the goal but still, that is surprisingly low. An earlier effort towards something like the A6M7s wing might be more useful.
You can, of course, up-engine and/or increase wing area for increased MTOW but neither will help your fuel consumption and early-war Japanese engines were quite power-limited.
Let's talk failure modes. Amateurs talk tactics, professionals talk failure modes. If that's not axiomatic, it should be.
When operating as a floatplane, even if temporarily, the main float and pylons must be considered to be primary structural members. The pylons must bear the full weight of the aircraft. They must withstand the drag from the float. That is a lot of wetted area, across two mediums, one of which is much denser and undulating. They will get lateral loading and compression during the take-off run as well but the killer, as with anything to do with aircraft, is always some combination of weight and drag.
So with this concept, you want to make multiple attachment points that must possess structural strength frangible?! You are purposely building-in structural failure modes. Frangible attachment points are guaranteed to fail before the aircraft gets “on the step”. The bolts will shear, as they must be designed to do. The forces involved are too great for otherwise, even in the most idealized flat calm.
Use some form of shaped charge? Any charge large enough to ensure a clean separation (of a non-frangible pylon) would undoubtedly cause collateral damage. On an aircraft with the Zero's/Zeke's/Rufe's reputation for flammability?
This really bears re-emphasis. The aircraft's landing gear must be an integral component, stressed to withstand impacts up to the aircraft's structural limits. It's severance can only be achieved by exceeding those limits. How then, is this purposeful vandalism contained, localized and prevented from becoming a loss-of-vehicle event? You cannot design a landing gear to both break and not break. You can have load-bearing or you can have separable. Not both. They are mutually exclusive concepts.
Speaking of separation, all of the drop tank jettisons I'm aware of involve some sort of pitch event. A notional fuel-float must have some residual fuel aboard. On separation, the float will decelerate, the fuel will slosh forward and the nose will pitch down. Except on a float, the forward section is a planing surface. Will this act as a lifting body and pitch the nose up? With such minimal prop clearance? Suffice to say having such a long object pitching unpredictably in close proximity to an aircraft before it has time to fall away gives me pause.
What if the notional floatplane is bounced in transit? What's the procedure? Jink and jettison? Separate and then hopefully still be around to jink? What way will it all go, punched off while in a hard bank with a boot full of rudder in?
I haven't mentioned the wing floats and asymmetric hang-ups. Aerodynamicists hate asymmetry.
What may be a theoretical boon seems like a real-world liability to me. It's an interesting concept that falls down the instant you give it to Nakajima to actualise.
With an A6M2-N as the base aircraft, assuming no increases in weight from the modified float for fuel carriage, pumps and no structural reinforcement necessary from the increased weight, the 'Rufe' has a difference between gross weight and MTOW of 926lbs. That makes an allowance for only 154 US Gals, only 69 US Gallons or so above that already available from a standard A6M2 drop tank for a great penalty in drag.
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I get that increased fuel isn't the sole object and that operational flexibility is also the goal but still, that is surprisingly low. An earlier effort towards something like the A6M7s wing might be more useful.
You can, of course, up-engine and/or increase wing area for increased MTOW but neither will help your fuel consumption and early-war Japanese engines were quite power-limited.
Let's talk failure modes. Amateurs talk tactics, professionals talk failure modes. If that's not axiomatic, it should be.
When operating as a floatplane, even if temporarily, the main float and pylons must be considered to be primary structural members. The pylons must bear the full weight of the aircraft. They must withstand the drag from the float. That is a lot of wetted area, across two mediums, one of which is much denser and undulating. They will get lateral loading and compression during the take-off run as well but the killer, as with anything to do with aircraft, is always some combination of weight and drag.
So with this concept, you want to make multiple attachment points that must possess structural strength frangible?! You are purposely building-in structural failure modes. Frangible attachment points are guaranteed to fail before the aircraft gets “on the step”. The bolts will shear, as they must be designed to do. The forces involved are too great for otherwise, even in the most idealized flat calm.
Use some form of shaped charge? Any charge large enough to ensure a clean separation (of a non-frangible pylon) would undoubtedly cause collateral damage. On an aircraft with the Zero's/Zeke's/Rufe's reputation for flammability?
This really bears re-emphasis. The aircraft's landing gear must be an integral component, stressed to withstand impacts up to the aircraft's structural limits. It's severance can only be achieved by exceeding those limits. How then, is this purposeful vandalism contained, localized and prevented from becoming a loss-of-vehicle event? You cannot design a landing gear to both break and not break. You can have load-bearing or you can have separable. Not both. They are mutually exclusive concepts.
Speaking of separation, all of the drop tank jettisons I'm aware of involve some sort of pitch event. A notional fuel-float must have some residual fuel aboard. On separation, the float will decelerate, the fuel will slosh forward and the nose will pitch down. Except on a float, the forward section is a planing surface. Will this act as a lifting body and pitch the nose up? With such minimal prop clearance? Suffice to say having such a long object pitching unpredictably in close proximity to an aircraft before it has time to fall away gives me pause.
What if the notional floatplane is bounced in transit? What's the procedure? Jink and jettison? Separate and then hopefully still be around to jink? What way will it all go, punched off while in a hard bank with a boot full of rudder in?
I haven't mentioned the wing floats and asymmetric hang-ups. Aerodynamicists hate asymmetry.
What may be a theoretical boon seems like a real-world liability to me. It's an interesting concept that falls down the instant you give it to Nakajima to actualise.
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Speaking of separation, all of the drop tank jettisons I'm aware of involve some sort of pitch event. A notional fuel-float must have some residual fuel aboard. On separation, the float will decelerate, the fuel will slosh forward and the nose will pitch down. Except on a float, the forward section is a planing surface. Will this act as a lifting body and pitch the nose up? With such minimal prop clearance? Suffice to say having such a long object pitching unpredictably in close proximity to an aircraft before it has time to fall away gives me pause.
What if the notional floatplane is bounced in transit? What's the procedure? Jink and jettison? Separate and then hopefully still be around to jink? What way will it all go, punched off while in a hard bank with a boot full of rudder in?
It's not clear on most views of a float plane (or flying boat really) but they are actually mostly pitched slightly "nose-down" to help the aircraft off the sea. (Being "level" they will then have the aircraft with a slight "nose-up" angle during take off)
If 'bounced' in flight like an aircraft with drop tanks they will "jink-and-jettison" almost at the same time and yes it's to ensure you clear the jettisoned object AND get out of the way of possible incoming fire
Randy
Stores clearance in general and the "store" in question in particular may prove more complicated than that. It isn't a trivial matter. That the store will move downward isn't in question. That it will do so in a timescale the pilot is comfortable with very much is. I would anticipate some pucker factor from the pilot. I thought the F-22 photo might prove instructive. Here it is proposed to jettison something of greater, unevenly distributed mass, more complicated shaping and less propulsive thrust.
Jettisoning an unknown while manoeuvring is just asking for trouble.
F-18 Drop Tank Test Disaster
An A-4 Skyhawk is caught in the middle of a disaster during the filming of a Navy F-18 bomb deployment test.
A video of a F-111 hoist with his own petard and an A-4 by someone else's.
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Actually that's WHY you maneuver instead of flying straight and level. It makes things a bit easier. If you have a choice you will usually actively maneuver away from the departing stores. Case in point:
F-18 Drop Tank Test Disaster
An A-4 Skyhawk is caught in the middle of a disaster during the filming of a Navy F-18 bomb deployment test.www.military.com
A video of a F-111 hoist with his own petard and an A-4 by someone else's.
(As an ex-Ammo troop we LIVED for these films/videos during training classes, for some reason the second part of the line "A4" isn't showing in the original post?
)Instead of continuing to fly straight and level, (where the aerodynamics and wake issues can bring things back as in this case) you move, (usually up and to the "off" side of the store you just dropped, a slight dive and then jettison as you pull up or a hard bank 'away' from the dropped store) to put distance between yourself and the store. (There's a reason you can find so many "failure-to-separate" films online as usually the aircraft IS flying straight and level due to it being a "test" environment. Example check out the 1:00 mark in this video HERE, suspect it's the same one you reference above)
Randy
Not all stores are equal. The relative length of this jettisoned component (the float) compared to the parent aircraft is unprecedented. The closest I can think of is the B-58 pod but that didn't have such a lengthy pylon plus canted secondary pylons. There is no way to know how they would interact with the prop wash or the boundary layer of the underside of the fuselage or vortices from the inboard trailing edges. As I said, this particular object has a ventral planing surface that will have unique effects. It may well prove perfectly benign but no-one can say that with any authority. It could equally be catastrophic. What it is, is an unknown. Unfortunately, I haven't had access to a wind tunnel since uni.
Yes, exactly but my point in post 67 was that the need to evade an aggressor, to jink, might mean you don't have that choice to also evade a sticky departing store. Escaping from one could carry you into the teeth of the other. It would depend on what the attack geometry was. Again, it could be perfectly fine, it could kill you faster than the enemy would. In any event, it would be an obstacle this pilot would have that a normal Zeke pilot wouldn't. His own act to save himself may kill him but any hesitancy definitely would.
Yes, exactly but my point in post 67 was that the need to evade an aggressor, to jink, might mean you don't have that choice to also evade a sticky departing store. Escaping from one could carry you into the teeth of the other. It would depend on what the attack geometry was. Again, it could be perfectly fine, it could kill you faster than the enemy would. In any event, it would be an obstacle this pilot would have that a normal Zeke pilot wouldn't. His own act to save himself may kill him but any hesitancy definitely would.
Kind of assume the ones planning this would test it first
Again this is a pretty standard process even in WWII, specifically with drop tanks. Sure a detachable float is going to be bigger and heavier but it's not like they won't be trained in (and have tested beforehand) the process. I think we're on the same page here.
The main question is still if the extra effort and hassle is worth said effort and hassle which I don't think is clear yet.
Again I'll point out that everyone in WWII was also thinking somewhat along the lines though I still think the "best" option was the retracting float which was proven in WWI.
Randy
Actually my working assumption is the ones planning this wouldn't need to as they would be drummed out of the office and re-assigned before the hardware stage. Can anyone point out to me an object dropped from an aircraft that protrudes so far forward of it's own dimensions? Follow-up question: did said aircraft have a single propeller in-line with said object? Even as phallic an arrangement as the TBD Devastator's tinfish is well astern in comparison. My expectation is that when detached, this thing is going to put it's ugly snout through the propeller arc.
Which, in this instance, is a completely academic point. Let me put this another way. The A6M2-N cruises at 184mph. That is one mph less than the 1935 Labor Day Hurricane. The same hurricane that did this:
The OP wants to expose a large and heavy structure to similar force with an in-built weakness to permit easy and rapid detachment in flight but that must simultaneously and paradoxically remain attached?
I'll be blunt. This would be an excellent suicide craft, in the finest traditions of the IJN, with a unique combination Frag-FAE warhead. As an additional terror tactic, it's range will be random.
I myself think not, but that discussion is going to have too wait till I'm feeling better, unfortunately.
Many posts, but I'm not up to making much right now, just want to ask, what was the take off speed of the Rufe, as opposed to the cruise speed?
I can only offer an unhelpful: it depends.
Aircraft weight, wind and sea conditions will all affect the answer. A flat calm isn't necessarily for the best. Sometimes seaplanes can be reluctant to unstick without a little chop. Usually some elevator input is used to create a rocking motion and unstick the floats in that instance.
There is a report on the flying characteristics of the Zero here:
Take-off speed is mentioned as 75mph, climb-out 80-85 & approach at 80-85mph. The Rufe is a little heavier and a lot draggier, so I'd be inclined to shoot for 80 for unsticking speed and err toward the upper end for climb and approach. It may well unstick earlier than that, if light, though I don't imagine it will be by much. At MTOW it will be more stubborn and I'd be inclined to stay down in ground effect passed 90 if left to my own devices.
Edited to add: This graph might prove instructive. It shows the drag forces on a floatplane peak "on the hump" before the planing phase of the take-off:
Taken from here:
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Contents: Current seaplane designs, Seaplane types, Symbols and definitions, Seaplane motions, Hydrostatic forces (displacement range), Dynamic forces (planing...
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A couple of points: IIRC, the Schneider Trophy float planes often used their floats as streamlined 'radiators' for engine / oil-cooling. This some-what offset the floats' drag...
Despite inherent streamlining, floats and their 'legs' are heavy and draggy. So, such aircraft are at a disadvantage in range and combat. Of course, if you must operate without even a 'corduroy' field, the choice is between 'flying boat' or float-plane. And a float-plane may be readily catapulted...
Speaking of catapults, remember the one-shot 'Hurricats' that 'bounced' those long, long ranged but comparatively fragile Condors spotting for Atlantic U-Boot packs ?? Suicidaly brave pilots, they put the 'WTF_??' into Condor crews before convoy escort carriers could be provided...
Despite inherent streamlining, floats and their 'legs' are heavy and draggy. So, such aircraft are at a disadvantage in range and combat. Of course, if you must operate without even a 'corduroy' field, the choice is between 'flying boat' or float-plane. And a float-plane may be readily catapulted...
Speaking of catapults, remember the one-shot 'Hurricats' that 'bounced' those long, long ranged but comparatively fragile Condors spotting for Atlantic U-Boot packs ?? Suicidaly brave pilots, they put the 'WTF_??' into Condor crews before convoy escort carriers could be provided...
STOP PRESS! It seems that the E15K, illustrated in post #65, was indeed designed with a jettisonable central float! Source:
Francillon's Japanese Aircraft of the Pacific War expands that: "the forward* pin could be removed thus releasing the entire float and increasing maximum speed by some 50 knots".
* of 2 pins
It's not made clear if this means the float falls clear from the pylon, which remains attached but the pylon is distinguished in the text from the float so I assume that that is the case. Were it the case that might (I emphasize might) provide the vertical clearance to allay some of my concerns. Were it to include the jettisoning of the pylon, those concerns would remain in full force.
Francillon goes on: "Six E15K1s, to be named Norm by the Allies, were sent to Palau for combat evaluation but were quickly shot down by Allied fighters as the ventral float jettisoning system, never previously tested, failed to operate."
Which would seem to validate both sides of this discussion. An arrangement I can eminently live with.
Now the question remains, how did it fail? There isn't a lot to go on but it's reasonable speculation to conclude that the pin in question would be both large and heavy and difficult to manipulate in a cramped cockpit, especially during combat.
So the question is, does anybody have more detail?
Hopefully the screenshot will be considered fair use.
Combat aircraft of World War Two : Weal, Elke C : Free Download, Borrow, and Streaming : Internet Archive
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Francillon's Japanese Aircraft of the Pacific War expands that: "the forward* pin could be removed thus releasing the entire float and increasing maximum speed by some 50 knots".
* of 2 pins
It's not made clear if this means the float falls clear from the pylon, which remains attached but the pylon is distinguished in the text from the float so I assume that that is the case. Were it the case that might (I emphasize might) provide the vertical clearance to allay some of my concerns. Were it to include the jettisoning of the pylon, those concerns would remain in full force.
Francillon goes on: "Six E15K1s, to be named Norm by the Allies, were sent to Palau for combat evaluation but were quickly shot down by Allied fighters as the ventral float jettisoning system, never previously tested, failed to operate."
Which would seem to validate both sides of this discussion. An arrangement I can eminently live with.
Now the question remains, how did it fail? There isn't a lot to go on but it's reasonable speculation to conclude that the pin in question would be both large and heavy and difficult to manipulate in a cramped cockpit, especially during combat.
So the question is, does anybody have more detail?
Hopefully the screenshot will be considered fair use.