KerbalKind

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About KerbalKind

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    Bottle Rocketeer
  1. which was why I made lots of unmanned probes to test things. I were so sure the fairings (2600K tolerance) could survive 73km periapsis or above (I have occasionally pushed to 71km). Until it didn't. Yes the fairing for A is 3.75m, while for B it is 2.5m. I thought it might contribute, but did not think it could make such a large difference on its own. Still I might make another craft with both just to test it. Edit: Okay, for what it's worth, here is an experiment with a new fairing for craft A. The craft is practically the same, but I split from a single long 3.75m fairing into two shorter ones. Old fairing: https://imgur.com/dQgWiIt New fairing: https://imgur.com/xUEG1C4 This new craft A now behaves very similarly to craft B, with the fairing barely heated up at 84km and surviving at 76km periapsis (some of the airbrake wing sections explodes, but they are a different matter) At 84 km: https://imgur.com/nD39052 At 76km: https://imgur.com/S1AhEnM So it's established that the fairing design (shape, length?) is the critical factor. Now, the question I still can't figure out is why they are so different? Just from an (amateur) look, the old fairing looks smoother aerodynamically to me.
  2. Craft A: 4540 m/s Craft B: 4629 m/s They can be seen in the images.
  3. Yes that was exactly what I was doing - only lower periapsis enough to aerobreak into a very high Eve orbit. Sorry if it wasn't clear. I thought I might include a previous craft of mine (craft B) to explain why I am puzzled at this latest one's performance (craft A). The craft is of similar design: fairings ahead and deployable airbrakes (made with wings facing the airstream attached to robotics hinges). It was a proven design so I was pretty confident before sending my kerbals to their destiny. I sent both to Eve-Kerbin transfer at the same window (couples of hours apart to switch control), so entry profile should be very similar. I got craft B to an even lower aerocapture periapsis (75km) than craft A (77km). Here is craft B's performance: - At 84km and 4628m/s (slightly higher than craft A), the fairing barely heats up: https://imgur.com/0CdJqlv - At periapsis (75km) and 4552m/s (almost the same as craft A at 84km), the foremost fairing heats up significantly but nowhere even near maximum temperature like craft A at 84km: https://imgur.com/tQRqgBi Craft B made a safe aerocapture to Eve. I am puzzled on why the thermal performance is so drastically different? - Is it because craft B is composed of 3 fairings instead of one big one? - Craft A is heavier (46 tons) compared to B (16 tons). But with similar entry speed and altitude, shouldn't atmospheric heating be the same? The majority of drags should occurs at the airbrakes (craft B only have 3 airbrakes, while craft A has 4, and each has larger break area to account for increased mass) - I had previous design with heat shield before, and could get them to much lower aerocapture periapsis (60-70km) to get captured by Eve. From previous experience, without heatshield the fairings will overheat at periapsis of 71km or below. I experimented with the deployable airbrake design using robotics hinge because: A/ it always allow aerocapture at 77k periapsis or above, well above the fairing tolerance range, so I don't need heat shield B/ can be scaled up for higher vessel mass C/ Much finer altitude control in the final circularizing aerobreak That's why I can't understand how craft A's fairing heats up so rapidly to maximum temperature at 84k altitude - fairings were only in danger zone at 71km or below before, and heating happened slowly over the entire trip, not so rapidly in 3-4s like this.
  4. Howdy, So today I am on a mission to put a space station around Eve. I put a large fairing over the entire station with many delicate components. However, upon entry and aerobreaking into Eve's atmosphere, the fairing part heats up very quickly and explodes, and I am uncertain of the reasons. I have been regularly doing aerobreaking into Eve with unmanned probes, so I think I have a good idea of the thermal tolerance of parts in this condition. I never have a fairing even close to explode at 84k km altitude from Kerbin-Eve transfer speed like this before. https://imgur.com/vRptlee: fairing part getting toasty https://imgur.com/3ZHU6nF: fairing exploded. All other parts are fine but starts to heat up once the fairing is gone Help! It's the first manned mission I ever taken to Eve after countless experiments with probes, and THIS decides to be the first one to actually have issues. I have enough fuel left to do a capture burn, and can send rescue later. So I'm more interested in knowing WHY? It just contradicts my experience from previous flights with fairing.