You’re very focused on keeping out the hijacks ChalkPit. You’ll be a moderator someday.
As I said before fighters as big they are aren’t that big and heavy as big planes go. Any plane that isn’t fully aerobatic has no business being a fighter to begin wiith. I suggest your search may be more fruitful if you look at large attack planes and medium bombers.
I used to be a moderator elsewhere - force of habit…
I’m just using heavyweight fighters as a starting point to move on from.
I’ll ask some of the test pilots here when I’m next on a day shift.
An outside loop is significantly more difficult to do, and much harder than the airframe, than inside loops.
An inside loop starting from a 2-g pull will be pulling 1g at the top of the loop. An outside loop started with a -2g pushover would be doing negative 3g’s at the bottom.
Transport category aircraft only have to be stressed to -1g. So right there, that eliminated the possibility of being able to do an outside loop. And if you could somehow enter the loop so slowly that you’d only be pulling -1g at the bottom, you’d never have the power to come back over the top.
I think your numbers are rather arbitrary. Of course a plane only stressed to -1G should not attempt an ouside loop. Pushover at the top can be gentle as airspeed should probably be low. Speed will increase on the way down and negative G load will be determined by how the pilot flies through the loop.
If you’re only pulling 1g at the bottom, you’d better have a hell of a thrust to weight ratio if you expect to make it back over the top again. We’re talking about the equivalent of rolling an airplane on its back, then pushing over the top. No way a transport category airplane will be able to do that.
I worded my post poorly but I never said the magnitude of force at the bottom of the loop was only 1G. It can’t be by definition as that’s level flight. If you climb out of the bottom of the loop you pull greater than 1G. Doesn’t matter if you use KE only in a glider or climb out with sheer engine thrust. The specific G load will depend on airspeed and the radius of the loop.
Are you assuming a constant airspeed? Not so, particularly with a plane that has lower thrust/weight ratio. Top of the loop will be highest airspeed and bottom will have the most ideally. No reason the pushover for an outside loop has to be -2G or even negative at all as long as it’s more negative than +1G. A marginal aircraft may make an egg shaped loop but it’s still a loop in my book.
Anyway the OP is a hell of a tough question to answer. Looking around I found specs for the A3 whale which is the heaviest carrier plane but it’s gross TO weght of 82,000lb and wingspan of 72.5" make it only incrementally larger than heavy fighters. At that I couldn’t find a case of an A3/B66 looping. We still had them on the Connie in the early '80s. Lumbering hulks they were I bet one could loop.
No answer as yet, but I found a report on a747SP (the shortened version) which pulled some pretty amazing manoeuvres (according to the flight data) which could possibly be construed as a loop in a loose sense. The plane pulled about 5g which popped the gear out. IT landed but the airframe was junked.
Other than that, having seen various displays of this aircraft over the years, before it was retired, I was thinkin about the Vulcan bomber. I’ve seen that being thrown around in quite amazing ways but couldnt say if it could loop.
I asked the Wing Commander upstairs, and he was stumped.
I have put the question to the guys at the test pilot school, but not had anything back yet.
I’ll keep yall posted.
Another thought - Rockwell B-1 ?
Apparantly the Vulcan (and Victor) would do loop-and-roll-out-at-the-tops at Farnborough airshows in the 50’s and 60’s.
Closing in…
Ok, for what it’s worth, I had a chat with a test pilot who has flown the B-1.
He hasnt looped it but reckons it has the power to weight ratio and G limit. His main point of concern was that the wings take ages to sweep back (he thought it was about 45 secs) and these would need to be moved during the course of the loop.
He said he would check out the flight manual he has at home for this aircraft.
You work at an interesting place ChalkPit, though I could do without the Harriers hovering outside the window. You probably have one of the few offices where hearing protection is required.
I think the Vulcan may be a good candidate for a plane that has known to have been looped. The Mk2 versions weigh about 200,000lb gross.
I’m curious about the B1 requiring wing sweep during the loop. Sweeping back or forward? The only thing I have to compare it to are the F-14s I used to work on but they have a different flight envelope. Wings are pretty much already swept back when speed is high enough to enter a loop.
Yes, its a plane spotters paradise here.
Just had someone from the Heavy Air Test Squadron, they had talked about it and put forward the Antonov An-124 as a possible, but they had no source to give me on it as proof.
I cant find anything on-line to support the suggestion, but you’d think they know what they’re on about.
What about helicopters? I could swear I saw a helicopter do a loop on television once. It was definitely a :eek: moment…I mean, at one point the helicopter is upside down; that means the rotors are pushing the heli DOWNward!
Not any more so than the wings of an airplane are pushing it “down” at the top of an inside loop. Lift relative to the airplane’s “up” is needed at all times to counteract the centifigual force of the loop.
For something really freaky there are a lot of radio controlled model helecopters that can fly inverted. I’m not aware of any full size helicopter that can.
The ability to do a true loop in a helicopter probably depends on wether its a ‘floppy’ like the Gazelle or ‘rigid’ like the Lynx.
Droopy blades are probably not conducive to inverted flight, but I’m just guessing here.
I’ve seen the Gazelle display teams pulling some great moves during displays but not sure I’ve seen one do a true loop, though I’m sure some helicopters can go all the way over, the Russian Mi28 and the Tiger spring to mind.
I’ll ask around here, we have a Rotary Test Squadron and the Empire Test Pilots School has a rotary section too.
Those RC choppers are amazing, seen some great displays at Elvington in North Yorkshire, which is an Air Show primarily for models - great stuff.
I’m not an authority on rotorcraft, but several rotorpilots I know have repeatedly emphasized that negative g’s and rotors do not mix. At least not their rotors. There might be some helis out there that can handle negative g’s, but I don’t know of any.
So… since an inside loop exerts postive g’s, a heli should, in theory, be able to handle it (unless a real rotorcraft pilot shows up and says differently) but outside loops sound like a real no-no.
Some helis, and a lot of model helis, can do outside loops, as well as hover upside-down.
As far as ultralights go, I once saw a pilot take off (barely) and cross a few hundred feet of field with his right wingtip about a foot off of the ground. He then pulled sharply up right before a treeline, cleared the trees by about 10 feet, then proceeded to loop right above the trees. The bottom part of the loop was no more than 20 feet off of the treetops. He then proceeded to go through all sorts of maneuvers which I can’t even try to name, though as I recall an outside loop was included. The aircraft was a Moyes Dragonfly, technically not an ultralight but the best plane in the world for aerotowing hang gliders. Incidentally, I think the current record for looping hang gliders is 57 in a row, although it’s not broken regularly for reasons of chivalry…any reasonably-skilled HG pilot can easily break this record.
Aero towing hang gliders ?
Wow, that I would like to see !
Come to the North American plains… with hundreds upon hundreds of miles of flat-as-a-pancake landscape about the only way to get a hang-glider launched is through towing. Oh, alright, we have a few hills around the edges of the Great Plains, but they’re pretty pitiful.
Out where I live, hang gliders tow-launch routinely.
I guess we are rather well off in this country for great hang gliding spots.
Just sounds rather dangerous, never heard of that before. Winch launching certainly but never heard of a aeroplane pulling a hang glider, just assumed the speed differential was too great.
Learn something new every day huh…