Boy, That Was a Big Bang
When the Army first started carry weapons on helicopters they searched around to see what worked best. After a bit the Mark-IV 2.75 inch rocket became one of the favorite weapons. The correct terminology was Mark-IV 2.75 inch Folding Fin Limited Spin Aerial Rocket. The rocket diameter was 2.75 inches, there were four fins that were folded in until the rocket was fired from the rocket tube, the rocket motor nozzles were cut at a 23 degree angle to make the rocket spin, and it was fired from the air. So the correct terminology really was correct.
The speed of the rockets was just below the speed of sound. When the rockets were fired there was a quick blast and the rocket was away. The noise of the rocket being fired wasn’t too bad but there was no doubt when a rocket had been fired because there was a flash of fire and a bang. The rocket motor burned for just under one and one-half seconds but during that period of time the rocket covered a lot of ground.
There were a variety of fuses and warheads used on the rockets. The standard basic warhead was called a “10 pounder” because it weighed ten pounds. It carried the same explosive power as a 155-millimeter artillery round and had a ten-meter killing radius but didn’t have as much shrapnel as the artillery round. There was also a 17-pound warhead. It looked just like the ten-pounder only longer, and made a little bigger bang when it exploded and covered a little bigger area. Additionally there was a flechette warhead that carried twenty-two hundred little darts that were dispensed after the rocket flew 1,200 meters. Also, there were a variety of colors of smoke warheads, riot gas warheads and white phosphorus warheads. Later, more warheads were added to include ones that dropped little bombs and some that would penetrate armor. In addition, there was a target round that just gave off some smoke to mark where the round had impacted.
Fuses included the standard point detonating type which would explode on impact, a delay fuse which delayed the warhead detonating until the rocket had penetrated the target a bit, and a proximity fuse which exploded when it got close to another object. Later more fuses were included such as the one that could be adjusted so that the warhead would go off at a certain distance.
When firing rockets at night it was important to close one eye just before pulling the trigger. To be able to see at night aircrews had to let their eyes adapt to the darkness. To achieve total night adaptation, or night vision, a person had to be in darkness for about forty-five minutes. Just seeing one rocket fired at night would wipe out much of a person’s night vision. Thus, if the pilot closed one eye just before firing the rockets he could maintain excellent night vision in at least one eye and be able to see in the dark after firing rockets.
Over the years I fired a lot of rockets and got to fire many of the different types. As other weapons developed and the warheads improved it became obvious that a better rocket motor was needed for the 2.75 inch rocket. So a better and faster rocket motor was developed. The new rocket was called the Mark IV Hydra 70. It accelerated to about two and half times the speed of sound. This baby really cooked! It was out of sight and gone in a flash and had a range of nine thousand meters.
The Mark IV Hydra 70 rocket came out while I was flying in the National Guard. We went up to Canada to play war and shoot at one of their great ranges and we were going to be able to shoot some new Mark IV Hydra 70’s. We had some standard Mark IVs left and we were to shoot them up before we started shooting the new Hydra 70s. Firing got delayed and we didn’t get started until the night.
On this trip I had a couple of new pilots to train. One of them was a young lieutenant who hadn’t fired anything before, day or night. Firing during the day and at night was required for a new pilot to be qualified in the weapons system and aircraft. We were only going to be on the range for one night firing so this was the only opportunity to complete the night firing with the new pilots.
The ground crews were supposed to let the pilots know when we changed from the standard Mark IVs to the Hydra 70s. I flew with one of the other pilots I was supposed to train first because he and I had been flying together during the day. After we finished shooting the targets he needed to qualify on I planned to switch to the lieutenant and then take my time to train him.
Some of the other instructors started flying and shooting at the range with the qualified pilots shortly after dark and about eleven o’clock the lieutenant and I made our first run down range. I had the lieutenant set up the switches and told him to select “one pair”, meaning for each trigger pull just one pair of rockets would be fired. That would give us nineteen trigger pulls total on the inboard rocket pods. He was in the back seat and was to do the shooting. After instructing the lieutenant on shutting one eye and telling him what to expect I had him aim at a target and then I told him to pull the trigger. Hovering fifty feet above the ground in the dark with one eye shut and trying to hold the aircraft on target was not easy. It took him a while to get settled down and to hold the aircraft on target long enough to pull the trigger but finally he pulled the trigger. I also had one eye shut waiting for the flash.
Suddenly there was a big bang and a blinding flash! It was not like anything I had experienced before so in my surprise I opened my closed eye. The flash of light was blinding but fortunately it was over with very quickly. Because the rockets were so fast I still had some night vision left and was able to maintain control of the aircraft. Almost immediately the range tower was on the radio asking me what I just did. I said, “Did the ground crews put Hydra 70 rockets on this thing and not tell me”? We continued to hover until the tower checked with the ground crews and sure enough they had put the Hydra 70s on my aircraft and they were the first ones we had fired in the unit. I told the tower that these new Mark IV Hydra 70 rockets were really wild. They had a really big bang and a huge flash.
After taking a few moments to prepare ourselves for the next big bang we were ready to do it again. The next shots didn’t seem to be as bad as the first shot had been. I kept thinking that the first shot seemed much louder than the subsequent ones but maybe it was because I was expecting a big bang this time.
Cobra pilots always knew how many rockets they had on the aircraft and tried to keep track of how many times they had pulled the trigger and how many rockets were left on board. I knew how many rockets were on board when I took off and how many times we had pulled the trigger. Before I expected us to be out of rockets we seemed to be empty. Most days and some nights I can count up to nineteen. Something didn’t add up that night.
When we landed back at the arming pad I had the ground crews check to see if I had rockets left on board thinking perhaps some of them had failed to fire. They told me that all the tubes were “clean”- all the rockets had fired. Perhaps I was a bit shaken when we fired that first shot but I still thought my count must have been right. I told them to load us up with a full load of rockets and we’d try it again.
On the second run things started the same way they did on our first run. The first trigger pull came with a huge bang and a big flash. Again the tower called and asked what I had just done. After that the shots didn’t seem as bad. By that point I knew what was going on. There must have been a short in the wiring going to those particular rocket tubes. Rather than igniting just one pair of rockets the first time the trigger was pulled it was igniting three pairs simultaneously. That’s why there was the bigger bang and flash of light on the first trigger pull. The rest of the night I had the ground crews leave two of those three tubes empty so I would just get one pair of rockets on that first trigger pull.
Shortly after that the Army banned the shooting of Mark IV rockets for a while. That was because there was so much blast from the rockets that the air around the tail rotor was so disturbed that on some occasions the aircraft would lose tail rotor control making the aircraft spin out of control and crash. The other thing they found out was that shooting the Mark IV Hydra 70 rockets could cause the engine to starve for air. That would cause an engine failure and a crash. All of the aircraft had to be modified so there was less chance the engine would starve for air and even then we were only allowed to shoot one pair at a time. I was sure that shooting three pairs at a time was really a challenge to the aircraft. It was a surprise to everyone that twice I had gotten away with firing three pairs simultaneously and not had either one of the problems which would have caused us to end up crashed and burned.
There are times when things pop up in life and take us by surprise. Some big bangs and flashes even open our eyes and shake us up. Sometimes that may be necessary or good. The question is what are you going to do then? It is important to remember that there are solutions to most things. And solutions are found by thinking and not by losing your cool. So when the big bangs and bright flashes come open your eyes and find solutions!
The speed of the rockets was just below the speed of sound. When the rockets were fired there was a quick blast and the rocket was away. The noise of the rocket being fired wasn’t too bad but there was no doubt when a rocket had been fired because there was a flash of fire and a bang. The rocket motor burned for just under one and one-half seconds but during that period of time the rocket covered a lot of ground.
There were a variety of fuses and warheads used on the rockets. The standard basic warhead was called a “10 pounder” because it weighed ten pounds. It carried the same explosive power as a 155-millimeter artillery round and had a ten-meter killing radius but didn’t have as much shrapnel as the artillery round. There was also a 17-pound warhead. It looked just like the ten-pounder only longer, and made a little bigger bang when it exploded and covered a little bigger area. Additionally there was a flechette warhead that carried twenty-two hundred little darts that were dispensed after the rocket flew 1,200 meters. Also, there were a variety of colors of smoke warheads, riot gas warheads and white phosphorus warheads. Later, more warheads were added to include ones that dropped little bombs and some that would penetrate armor. In addition, there was a target round that just gave off some smoke to mark where the round had impacted.
Fuses included the standard point detonating type which would explode on impact, a delay fuse which delayed the warhead detonating until the rocket had penetrated the target a bit, and a proximity fuse which exploded when it got close to another object. Later more fuses were included such as the one that could be adjusted so that the warhead would go off at a certain distance.
When firing rockets at night it was important to close one eye just before pulling the trigger. To be able to see at night aircrews had to let their eyes adapt to the darkness. To achieve total night adaptation, or night vision, a person had to be in darkness for about forty-five minutes. Just seeing one rocket fired at night would wipe out much of a person’s night vision. Thus, if the pilot closed one eye just before firing the rockets he could maintain excellent night vision in at least one eye and be able to see in the dark after firing rockets.
Over the years I fired a lot of rockets and got to fire many of the different types. As other weapons developed and the warheads improved it became obvious that a better rocket motor was needed for the 2.75 inch rocket. So a better and faster rocket motor was developed. The new rocket was called the Mark IV Hydra 70. It accelerated to about two and half times the speed of sound. This baby really cooked! It was out of sight and gone in a flash and had a range of nine thousand meters.
The Mark IV Hydra 70 rocket came out while I was flying in the National Guard. We went up to Canada to play war and shoot at one of their great ranges and we were going to be able to shoot some new Mark IV Hydra 70’s. We had some standard Mark IVs left and we were to shoot them up before we started shooting the new Hydra 70s. Firing got delayed and we didn’t get started until the night.
On this trip I had a couple of new pilots to train. One of them was a young lieutenant who hadn’t fired anything before, day or night. Firing during the day and at night was required for a new pilot to be qualified in the weapons system and aircraft. We were only going to be on the range for one night firing so this was the only opportunity to complete the night firing with the new pilots.
The ground crews were supposed to let the pilots know when we changed from the standard Mark IVs to the Hydra 70s. I flew with one of the other pilots I was supposed to train first because he and I had been flying together during the day. After we finished shooting the targets he needed to qualify on I planned to switch to the lieutenant and then take my time to train him.
Some of the other instructors started flying and shooting at the range with the qualified pilots shortly after dark and about eleven o’clock the lieutenant and I made our first run down range. I had the lieutenant set up the switches and told him to select “one pair”, meaning for each trigger pull just one pair of rockets would be fired. That would give us nineteen trigger pulls total on the inboard rocket pods. He was in the back seat and was to do the shooting. After instructing the lieutenant on shutting one eye and telling him what to expect I had him aim at a target and then I told him to pull the trigger. Hovering fifty feet above the ground in the dark with one eye shut and trying to hold the aircraft on target was not easy. It took him a while to get settled down and to hold the aircraft on target long enough to pull the trigger but finally he pulled the trigger. I also had one eye shut waiting for the flash.
Suddenly there was a big bang and a blinding flash! It was not like anything I had experienced before so in my surprise I opened my closed eye. The flash of light was blinding but fortunately it was over with very quickly. Because the rockets were so fast I still had some night vision left and was able to maintain control of the aircraft. Almost immediately the range tower was on the radio asking me what I just did. I said, “Did the ground crews put Hydra 70 rockets on this thing and not tell me”? We continued to hover until the tower checked with the ground crews and sure enough they had put the Hydra 70s on my aircraft and they were the first ones we had fired in the unit. I told the tower that these new Mark IV Hydra 70 rockets were really wild. They had a really big bang and a huge flash.
After taking a few moments to prepare ourselves for the next big bang we were ready to do it again. The next shots didn’t seem to be as bad as the first shot had been. I kept thinking that the first shot seemed much louder than the subsequent ones but maybe it was because I was expecting a big bang this time.
Cobra pilots always knew how many rockets they had on the aircraft and tried to keep track of how many times they had pulled the trigger and how many rockets were left on board. I knew how many rockets were on board when I took off and how many times we had pulled the trigger. Before I expected us to be out of rockets we seemed to be empty. Most days and some nights I can count up to nineteen. Something didn’t add up that night.
When we landed back at the arming pad I had the ground crews check to see if I had rockets left on board thinking perhaps some of them had failed to fire. They told me that all the tubes were “clean”- all the rockets had fired. Perhaps I was a bit shaken when we fired that first shot but I still thought my count must have been right. I told them to load us up with a full load of rockets and we’d try it again.
On the second run things started the same way they did on our first run. The first trigger pull came with a huge bang and a big flash. Again the tower called and asked what I had just done. After that the shots didn’t seem as bad. By that point I knew what was going on. There must have been a short in the wiring going to those particular rocket tubes. Rather than igniting just one pair of rockets the first time the trigger was pulled it was igniting three pairs simultaneously. That’s why there was the bigger bang and flash of light on the first trigger pull. The rest of the night I had the ground crews leave two of those three tubes empty so I would just get one pair of rockets on that first trigger pull.
Shortly after that the Army banned the shooting of Mark IV rockets for a while. That was because there was so much blast from the rockets that the air around the tail rotor was so disturbed that on some occasions the aircraft would lose tail rotor control making the aircraft spin out of control and crash. The other thing they found out was that shooting the Mark IV Hydra 70 rockets could cause the engine to starve for air. That would cause an engine failure and a crash. All of the aircraft had to be modified so there was less chance the engine would starve for air and even then we were only allowed to shoot one pair at a time. I was sure that shooting three pairs at a time was really a challenge to the aircraft. It was a surprise to everyone that twice I had gotten away with firing three pairs simultaneously and not had either one of the problems which would have caused us to end up crashed and burned.
There are times when things pop up in life and take us by surprise. Some big bangs and flashes even open our eyes and shake us up. Sometimes that may be necessary or good. The question is what are you going to do then? It is important to remember that there are solutions to most things. And solutions are found by thinking and not by losing your cool. So when the big bangs and bright flashes come open your eyes and find solutions!
posted by Bruce | 4:44 PM
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