Every image I can see of a cruise missile they have tiny wing stublets but they can fly at low altitudes for thousands of km with no problem? Eg they are not on a parabolic ballistic path.
How do they do this in terms of aerodynamics and why don’t other planes (eg drones) use this wing configuration?
Eg see google image search examples:
https://www.google.co.th/search?q=cruise+missile&espv=2&biw=1295&bih=929&source=lnms&tbm=isch&sa=X&ved=0ahUKEwjsvomiiKHJAhWk5qYKHYYeCisQ_AUIBigB
According to Wikipedia, the longest range cruise missiles only have range of about 1,000 km, so you might have to re-think your premise.
This is pure nitpickery. The premise of the question is equally valid whether cruise missiles cruise hundreds of km or thousands of km.
The question is how do they fly with those stubby wings, something I’ve wondered about as well.
The wings of cruise missiles are small, but not really stubby. By that I mean they have a fairly high aspect ratio. Aspect ratio is the ratio between wingspan and wing width and along with airfoil cross-section is the major determinant of how efficiently lift is produced. Another to say it high aspect ratio wings are slender. Aircraft looking for long, low drag flights have high aspect ratios. Think of gliders, airliners, human powered aircraft: all high-aspect ratio planes.
What the cruise missile certainly lacks, though, is much in the total wing area department. It can generate lift well but it has to fly at a much higher speed to do it. Long range cruise missiles generally fly at 500 mph and above. You’re not going to see them slow down to 100 mph and stay in the air. That’s just not part of their flight regime.
That’s what I was thinking. They’re air launched, so they never have to fly any slower than their cruise speed. Factors like takeoff speed and runway length aren’t part of the design.
I heard something similar about the Schneider Trophy racers in the '20s. They were the fastest airplanes of their day, and were all seaplanes. I thought that was odd, then I read the reason why; they were so optimized for high speed that it took them several miles to go fast enough to take off. There weren’t any runways long enough.
What about SLCMs?
They use rockets to get them up to altitude and speed, then the wings unfold and they go cruising. It’s not much different than an air launch, as far as the wings are concerned. In both, the wings are only used once the missile has enough airspeed for them to work.
Also, keep in mind they are a single purpose and single use device. No need for pilot comforts or necessities. Not much variety in payload weight or size. And as others point out, assisted launch and pretty much single speed. The wings are the minimal required.
Consider, motorcycle versus car design.
I think another factor is the low altitude. Most other types of aircraft are optimized for higher altitude. The higher the altitude, the lower the air density, and the larger wings you need to generate lift.
Indeed. One might ask, 'How to F-104s fly? (wing size)
(The F-104 was called a ‘missile with a man in it’ – along with other, les-complimentary things.)
Of course, the reason the wings are small is that the missile spends most of its existence in storage or transport, usually in tubes. Only the last few minutes or hours of a missile’s “life” are spent flying. So the wings are stored folded or retracted somehow, and are as small as practical. They pop out and lock into position during launch.
Better yet, consider the “wings” on the Northrop HL-10.
To paraphrase: with a powerful enough engine, you can make a barn door fly.
When I first started working in my career, I gathered flight test data on the AGM-86 and AGM-109.
We come back to the square-cube law: increasing dimensions by a factor of 2 increases the area by a factor of 4 and the volume by a factor of 8.
It’s a reasonable enough approximation to consider that volume and weight are broadly linear with each other and to only consider the lift that comes from the wings.
So, when you decrease the dimensions by a factor of 2, you will need half as much wing area proportional to the rest of the aircraft because your total surface area has shrunk by X4 but your weight has shrunk by X8.
To give a point of comparison, a Tomahawk weighs about 1.3 ton and a A-10 ready for a CAS mission weighs around 21 tons or 16 times more.
As another example of this principle: SDBs have small wings too and they have a glide ratio of 10:1 : http://defense-update.com/images_large3/sdb_ii_34.jpg
The F-104 what I was thinking of when I read the OP.
I don’t know whether or not it was a good jet, but it certainly was one of the most badass looking jets ever made, IMHO.
Agree. As to whether it was a good jet, it had a pretty dismal safety record, especially in Germany, which lost nearly a third of its aircraft, and Canada, which lost nearly half. (The Spanish Air Force didn’t lose any.)
In combat, four Pakistani F-104s were lost to Indian MiG-21s. From this site:
The F-104 was a slashing interceptor, not a dogfighter. The MiG-21 was a pure dogfighter.
With modern weapons there would be some ways for the F-104 to be effective against a MiG-21 also magically equipped with modern weapons.
But with actual period weapons from the '60s it’s sorta like a lancer with no horse fighting on foot against an infantryman with a short sword. Unless the infantryman is asleep or inept he’ll duck inside the first (and only) lance thrust and then close for an easy kill.
Really? I’ve always thought of the MiG-21 as an interceptor, or at leastiinterceptor-like. Wikipedia says:
The term “fighter” is broader than and inclusive of “dogfighter” and “interceptor”. “Interceptor” itself includes “dogfighter” but also the “slashing” kind of interceptor which doesn’t slow down and just launches missiles. The F-104 was in the fighter category, interceptor subcategory and it was designed to take out other aircraft mainly with missiles. The MiG-21 was also a fighter in the subcategory interceptor but it was designed to do its intercepting mainly using dogfighting with guns (the missiles listed as its armament came out 1.5-3.5 decades after the MiG-21 was first produced).
If you look at the specifications and plans of both aircraft, you can see that the F-104 is more like a manned cruise missile with stubby wings that launches other missiles whereas the MiG-21 has more wing area while being lighter. Those choices make the F-104 better at carrying more payload further whereas the MiG-21 should be able to maneuver more easily to shoot with its guns at close range.
Note how the dry thrust (the one used to maximise payload and range) of the F-104 is 25% higher than the MiG-21’s. However, the wet thrust (which would be critical during dogfighting) of both aircraft is equal even though the MiG-21 is significantly lighter.
Ok, fanboys: You all know about the dramatic movie Starfighters? It consists almost entirely of stock F104 footage and the struggle of brave sexy pilots (including a future Congressman) expounding on, and being shown, how great the plane is. The nemesis is a foolhardy skinflint real, fictional Congresscritter who wants to shut the program.
Extraordinary product promo, but released in theaters as a feature. Also, I learned everything I need to know about jet pilots, so Tom Cruise taught me nothing later.
Excerpts are here, beginning with interminable refueling shots. MST3K - Favorite Moments - The Starfighters - YouTube
The entire movie is also available on YouTube/MST3K-ized.
