totoromy best bet would be that it’s got to do with weight savings. it may’ve been decided that weight savings outweigh the visibility reduction.
original design may’ve had canopy of uniform thickness, being without any support. to withstand all the pressure, it may’ve been pretty thick and heavy. which made it impossible to break through it in case of needed pilot ejection. so then added mechanisms for detaching and blowing off the canopy with entire frame was needed. that also exposed the HUD to sudden pressure and regular HUD might have broken right into pilot’s head, so the original HUD was beefier (and slightly heavier).
the new design incorporated a frame underneath the canopy, like on f35. and features explosive lines on the roof of the canopy, like f35. it seems likely that whole rear part of canopy is thus of thinner material and is thus lighter. the blowing off mechanism is also not needed and the HUD could be made with much smaller frame, as visible on images.
Overall, weight savings might be over 100 kg, but that’s just my guesstimate.
totoroit’s some ten days old news, so in some sense it is new to those who haven’t read it a week or two ago. it’s exciting news, of course, correlating what we’ve been told earlier that first flight of prototype is expected in 2019. six-ish years for full funded development once a preliminary design has been settled on sounds about right for a project of that scale.
totoroj20’s fuselage is more voluminous than f22, by quite a bit. roughly speaking by 8 cubic meters. while there are too many unknowns – we don’t know if the materials will be very different for example, it is perfectly plausible j20 will be 10 or 20 or more percent heavier. but hey, that’s what wing area and canards are for, as well as the long term prospects of possibly larger engines.
totorothe whole su35 talk issue could be an internal arrangement between sukhoi and china so su35 gets exposure, potentially helping it with international sales. even just talk of china getting some could be seen as a sign of quality product to third parties, let alone china actually buying it. but that’s just one of dozens of wild theories out there.
totoroI don’t know for later f-16s, but SAC document for f16a block 15 shows a graph where maximum nonafterburning altitude for 24000 lbs plane is around 45.000 feet. for the same plane weighing 35000 lbs its around 35.000 feet. but i am not sure if the graph means the weights are take off weights or actual weights at the time of highest altitude.
totoroThat calculation may have a few mistakes/omissions. Lot of sources mention a 12 degree ramp. Also, average resistance isn’t clearly calculated but stated as a final figure. Total drag and rolling resistance before leaving the ramp is much less, and even up to 300 km/h total drag is unlikely to get to 6000 N. So i’d say that’s overstated. Perhaps my calculation is wrong, but even when using obscenely large figures for flanker’s Cd and area, i still got under 200 N of aerodynamic drag at 100 km/h and under 600 N at 200 km/h. With rolling drag under 1000 N, total drag at takeoff is really a fairly small force.
What’s also overstated is total thrust. Calculation mentions 12500 kgf per engine, which is uninstalled thrust and certainly unattainble at the very start of the take off. Using one available graph for f100-100 on f15 as a comparison, i don’t think it’d be wise to use more than 80% of that thrust as actual installed thrust. It will increase as plane gathers speed, but even at 250 km/h it was shown at around 90% of uninstalled static SL thrust. (engine installed on f16 allegedly does 75% of uninstalled thrust at the beginning of take off. but that figure is just a claim of an engine technician, i’ve no graph for it)
I had hoped for a tables with calculations from a proper source, but that’s okay. that translation of Fomin’s work is more than enough. I appreciate it greatly! 🙂
totorobut this was an image. i tried word recognition myself but only got gibberish. are you saying google translate also has option of word recogntion, and this quality translation is the result?? I find that hard to believe but it’d be a life saver!
anyway, where on the bottom of the page is calculation of ramp take offs? Last two images? I don’t see anything of the sort in them…
totoroWow, I had hoped for a short summary, didn’t expect anyone would do a full translation. Thank you, Paralay. Thanks a lot! :))
Too bad there’s no context with wind over deck speed but at some other part of the text there is a mention of 21 km/h wind over deck being expected or something… I guess i should include that figure in these 28/32 ton figures?
totoro[ATTACH=CONFIG]225389[/ATTACH]
Could anyone of the russian speaking members help me with this bit of text? What is exactly being said when they talk about launch positions, 25-28 tons etc in the first column and what do they talk about in the second column where various speeds are mentioned (220, 240, 270 km/h) and some distances (90m?) Thank you.
totoroz19 is a pretty light attack/recon helo at 4 ton mtow. there’s not that many subsystems to be put on it. initial variant has been seen in service with five different brigades, for some 80ish airframes total. What is in development is the follow up variant with a mast mounted radar. images of tests of that variant have leaked out recently. it would further point to the intended role of z19 – not to get up close and personal (it has neither the armor for it nor does it have a gun) but to stay away and observe, with radar if possible, and strike with missiles from a distance when appropriate.
totoroi am afraid i don’t follow you. could you rephrase your thoughts? wave length choice is dictated by size of what? parts on the plane? or the seeker in the missile?
do you want to say that majority of performance of ARH missiles won’t come from return of tiny radar returns from tiny features on the plane (otherwise invisible to longer wavelengths) but from direct radar returns of large surfaces?
totoroi posed this question in another thread already, but it got lost in the noise. maybe this is a bit better, if far less visited, venue.
what sort of useful tracking ranges are seekers on meteor/aim120d and the like expected to have against the likes of f22, f35, j20, pakfa etc? 50% of their range against 4th gen aircraft? 20%? or even less?
VLO aircraft aren’t new, but the current and even future plans for BVR missiles keep including radar seekers. That’d suggest their users do expect them to be useful, even if at somewhat decreased ranges.
And there may be some logic behind it. On one hand, shorter wavelengths are easier to combat with radar absorbant materials, but on the other hand, each bandwidth will have its own set of parts of the plane to work against. L bands will totally miss all the little bumps and gaps, but sub X bands may very well be perfect to pick up on various tiny antennas, distributed EO arrays around the plane (which need to be transparent, meaning at best a gold tinted cover for total reflection against one angle) and all sorts of gaps on the plane. While we do know gaps have been worked on both on f22 and f35, isn’t it likely that different sort of gaps can be treated with different efficiency?
For example, gaps between plane parts that are separated only a few times in the lifetime of the airframe may be treated in the best way to combat radars. Gaps between panels for regular maintenance may be treated worse than that, but still fairly okay. Gaps between panels that are regularly opened and closed for each sortie may be harder still to treat.
On top of that what about various tiny scratches, dirt, bird droppings etc. that may happen between sorties or even during a sortie? Could all those concievably be aiding the sub x band radars? And if so, are the makers of aim120d, meteor etc counting on those to help keep their missiles relevant even against VLO planes?
totoroHere’s another question: How will current and future derivatives of active radar guided missiles perform versus current and future LO planes? Basically, how will meteors, aim120d, rvv-sd, pl-15 etc perform against f-22, f-35, j-20 etc.
A decade or two ago publications were usually saying how tracking VLO planes with small wavelengths would be terribly inefficient and how even if VLO planes would be detected, they wouldnt be tracked and they surely wouldnt be able to be fired upon as there’d be no way to target them.
But since then we’ve actually seen not a decline but a proliferation of active radar guidance on missiles. now it’s not just pure bvr class missiles getting ARH, but also shorter ranged, smaller missiles. Also for SAMs, where before command guidance or IR guidance was the main choice, now we have the likes of CAMM, VL mica or VL Iris-T SL, all with ARH guidance.
Would all that point to a certain portions of VLO planes that are very hard to hide in that sub X band spectrum? Stuff like tiny antennas and gaps between control surfaces, doors etc? Stuff that is usually considered too tiny to be picked up by tracking radars in fighters/awacs/land based SAMs (and at the same time too hard to change in shape or coat with RAM due to their design and mission), but is actually just of right size to be picked up by even smaller wavelengths used in missile radars?
Logic would suggest that we would not see such a proliferation of ARH seekers if such method would be useless against VLO planes.
totoroVersion of ws10 which has been in service for some 4 or so years now on the j11b fleet, the ws10a, has in itself 132 kn thrust. al31fm1 matches that thrust, but it may offer longer time between maintenance or better spool up rates. thrust wise, though, is similar. there could be a difference in weight, though, where ws10a might weight more even if it offers same thrust. and we don’t know dry thrust figures for ws10a, so it’s theoretically possible dry thrust figures are lower than al31fm1.
it will be interesting to see what the next variant of ws10 will bring. that being said, what other two engines are in the same thrust class? 90-100 kn ws13? 90-100 kn ws9? 150-180 kn ws15? i’m not sure i’d call any of those engines of the same thrust class.
totoromack8, do you have more sources about 2003 pak-fa contest entries? i know that mig had a side intake proposal for original mfi, but that was back at the end of cold war. aftwards it redesigned its plane to what 1.42 eventually was.
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