sevenperforce

I can't tell from the picture whether the LV shown has 2 or 4 roll thrusters. And yes, it's significant that they didn't use a mortar to kick it up. We know it's not peroxide a la Black Arrow. The reason I was thinking kerosene was due to the slight purplish hue, though upon review, it does look a bit like Proton. Could easily just be the color of the dirt around the pad. Well, you're looking at a VERY tight engine cluster there, with some underexpansion, so it won't be about the same. But, see above; it does look a lot like the Proton. Also, there's no icing on the exterior of the missile. Not the first! It's not their first multistage cruise missile, but it's the first one which definitely has intercontinental range.

One note -- if you are using PVC and a composite or metal nozzle, you may want to try edging/sawing fracture lines in the PVC so that if it does overpressure, it will unzip along one side neatly rather than going to shrapnel. And of course you'd need to do some destructive burst testing first, just to make sure the fracture lines work as intended.

As you probably know, North Korea launched its first ICBM yesterday. Here's the propaganda shot: What can we figure out from this image? We've got a central plume with two adjacent plumes. The plume is clear, so it's obviously a liquid-fueled engine. The barely-visible Mach diamonds suggest slight overexpansion. The two adjacent plumes are parallel to the central plume, so they're not Atlas-type differential Verniers. More likely they are for roll control, which means they can gimbal. I'm guessing kerolox based on the plume color but I'm not sure. Anything else we can determine?

Tempted to go ahead and just start on EM-2 and the DSG...

Certainly. Which is precisely why there should be a cap. Otherwise the winner is whoever spends the most time on the challenge.

Oh, this is very inventive! I like it. Suggestion: put a limit on the number of additional kerbals, or something. Otherwise the winner is whoever spams the most kerbals, and that's no fun.

Use offset to move your rear gear up significantly.

You have to be careful about flaps; depending on your airspeed, giving them too much authority can cause flow separation and a stall, which actually decreases your lift. Better to use longer flaps (i.e., longer chord length) than to stall them out. Any chance we can get a screenshot? That might help with troubleshooting. One thing I mentioned before that's very useful: lifting your rear gear and lowering your forward gear allows you to already be pointed upward when you are taxiing toward takeoff, which gives the entire wing a high AoA and really kicks up the lift.

Well that makes it very straightforward!

Might give this a shot.

Try lowering the rear gear so you're nose-up on takeoff, and adding flaps (or more flaps, or flaps with a greater deployment range). If nothing else works, add an angle of incidence (this will lower your max speed, though).

In that case, I'm in.

What's more efficient? Launching a bevy of GTO payloads into LEO along with a couple of refuelable bipropellant tugs and an expendable propellant depot, or sending the whole terminal stage on a GTO trajectory and then using burns to change the argument of periapsis between each payload release? I daresay the former would be more efficient if the tugs could carry small heat shields and return to LEO by aerobraking.

You'd need space tugs.

The F-1 engines on the Saturn V had a pretty significant gimbal range. Were the tail fins on the first stage really necessary? Did they provide active or passive guidance?

KerbAir has announced its first entry into the small regional jet challenge, the Flying Fish. While some claim the Fish is ungainly, we at KerbAir prefer to think of it as uniquely elegant. In any case, whatever it may lack in perceived aesthetics it more than makes up for in performance and price. At just shy of $9.8 million, it is by far the cheapest available aircraft in its class and the only regional jet with a sticker price under eight figures. This cost savings is achieved by the use of a streamlined profile and minimal part count. With only 18 separate components and a single engine, any mom-and-pop airline can perform all the required service in-house. A novel V-tail eliminates the added cost of a vertical stabilizer, with KerbAir's proprietary SAS technology allowing the V-tail to control both pitch and yaw. The canards used for the V-tail are obtained via a special arrangement with the TweakScale Corporation, giving KerbAir access to secondhand, undersized parts at reduced prices. The Flying Fish obtains all its control with just four control surfaces, reducing maintenance associated with moving parts. The streamlined ailerons double as flaps for liftoff and landing. But don't let its economy-grade pricetag fool you! The Fish's powerful single engine propels it to its takeoff speed of 71 m/s in just over 500 meters, allowing it to take off and land on virtually any runway. Plus, the engine has a reversible thrust setting, permitting it to execute ultra-short landings as needed. Its low mass and powerful engine allow it to climb to cruising speed and altitude in as little as five minutes after takeoff, critical for regional jets. With a cruising speed of a little over 250 m/s at just under 10 km, it is not the fastest jet in its class, but its fuel economy is impressive with a range of 1,720 km. What's more, this range is achieved with a total fuel load of just 400 units in a single tank, making each flight's fuel cost just $320K. With a full passenger load this equates to just $7.75 per passenger-km. Pilots may notice that turns and landings can be challenging without a proper vertical stabilizer, so caution and careful control are recommended. Lowering the rear landing gear may help prevent excessive yaw on approach, at the cost of a little added drag. If your airline has an aircraft body shop on site, setting the angle of wing incidence back to zero (easy, since the wings contain no fuel tanks) allows for simple conversion to a high-speed executive express jet. The express variant (the Flying Sculpin), has a higher takeoff speed but can easily surpass Mach 1 in cruise. Craft file here. If you happen to reset the wing incidence to test the express variant, be sure to re-angle the front gear correctly to compensate. Flaps (action group 1) are recommended for takeoffs below 80 m/s. Thrust reversal is set to action group 2 so that you can spin up the engine in forward-thrust mode before releasing the brakes, enabling shorter takeoffs.

Cruising speed is the speed at which you obtain the highest range. Typically, this will be as high in the atmosphere as your craft can sustain level flight, since flying higher reduces drag and thus allows you to increase speed and decrease fuel consumption. I usually just go to full throttle and climb gently until I start having difficulty maintaining a steady ascent; at that point, I level out, set trim if applicable, and wait until my speed becomes constant. At this point, f/r*v (remaining fuel divided by fuel consumption rate times speed) gives me my remaining range in meters. If your plane has a very high L/D ratio, then you may find a greater range is achieved by throttling down to 80% or so once you reach cruising altitude. But most of my planes find their optimal cruising speed at full throttle.

Ditto on this. You should specify "on Kerbin, from LKO, engines cannot be used in the atmosphere".

I daresay building a Saturn V out of Legos IS your parenting duty.

Then I'll submit an unscored version. EDIT: Or you can just ask people to avoid abusing TweakScale.

https://www.washingtonpost.com/news/speaking-of-science/wp/2017/07/01/no-alex-jones-nasa-is-not-hiding-kidnapped-children-on-mars-nasa-says/?utm_term=.425cd60ca4b6

Okay, that's what I was trying to figure out. Tweakscale is pretty balanced; it should really be allowed. At least have a mod/no-mod leaderboard.

So is Tweakscale allowed, or no?

Very nice! I used launch clamps pointed exactly the same way. I just kept having trouble with burning up the Goliaths. Plus the hard landings.

IMHO, the critical difference is that the shuttle was dealing with a much more punishing re-entry and had localized TPS. Orbital velocity is much higher in KSP. Mk3 parts can handle re-entry from LKO at a wide range of attitudes and have pretty much equal thermal protection on all sides. If LKO was higher-velocity and Mk3 parts had TPS only on the underside, requiring a fixed high-AoA entry, then KSP spaceplanes would also have trouble with too much lift on entry. You'd have to use a ton of RCS or a bunch of reaction wheels to maintain attitude since you'd be losing speed much faster than you lost altitude. If you were flying in without reaction wheels or significant RCS authority, then you'd need to do something like the S-turns.