Thank you to Col. Hank Hoffman for this presentation.
This briefing is not really going to be about me. It’s about history and money and engineering, and I understood very damn little of it when I reported to the A-37 in 1970.
Let me take you back to 1967. The Vietnam War was still expanding with 485,600 US troops on the ground. I and 600 other crewmembers were flying B-52s into Vietnam out of Guam, so I’m not sure if this number included me.
Air Force tactics and strategy were dominated by nuclear doctrine. The Cold War Triad Doctrine consisted of nuclear weapons on alert in silos, submarines and bombers. The Strategic Air Command, known by the acronym SAC, ran two of the three delivery systems. And they were top dog in the procurement process. The Tactical Air Command, TAC, ran fighter operations and money was not plentiful.
This was the age of the supersonic fighter, and TAC commanders were looking to the future. They wanted new aircraft that were supersonic with the best technological advances. This meant the century series fighters and the Navy’s F-4 were what they were interested in. But they too were driven by the nuclear war paradigm. The majority of the fighters were interceptors owned by ADC, Air Defense Command, meant to fly supersonic to a bunch of Russian bombers, take them down, and probably bail out, out of fuel over the frozen north. Some of our bombers had the same “one way” tactic; hit the target and bail out in the fallout zone. The Air Force used all of their fighter systems in Vietnam. In fact, they often used the Vietnam conflict as a testing ground for new equipment. The interceptors, the F-101, 102, 104 and 106 were completely ineffective in the CAS role. That left the F-105 to bomb North Vietnam, and the F-100 for everything in South Vietnam.
Close Air Support, CAS, was not a mission dearly beloved by AF staff. Air Superiority was what the AF was born to do, and that was most important to them. CAS meant bombing near to friendly troops and it was the Army that wanted their troops supported. The Air Force wanted to go fast and high and look cool. In fact, Close Air Support had not been well supported by the AF since they separated from the Army in 1947. During Korea there was a noticeable lack of radio contact between the air and the ground, but it did see the beginning of the Forward Air Controller, FAC. The first FACs were required to be fighter pilots, and it was the beginning of a much despised role for them, flying low performance propeller aircraft, eating MREs and sleeping in the mud with the troops was less than attractive. In my opinion, one of the best things about air combat was the clean sheets and air conditioning you got at the bases, not to mention the booze.
Most of the fighter bomb delivery systems were nuclear driven as well. They sometimes used the “toss” bomb tactic, where you flew to the target on the deck, as low and fast as possible: then pulled straight up and released the bomb vertically, pulled hard to get back down to the deck and ran while the nuke continued up and, inevitably, down. That accuracy was acceptable for nuclear bombs, which pretty much destroyed everything for miles, but was not conceivable for a Troops In Contact, TIC, situation.
So the AF used what was available for Close Air Support. That was most often the F-100, and the Vietnamese Air Force also had the F-5 and the A-1 available. Note that the F-4 had inherited the air superiority role from the F-86 and the F-100 by now, and was mainly used in the air to air mission.
US commanders were sometimes reluctant to trust the Vietnamese, but gleefully took help from anywhere they could when they were under fire. The Vietnamese were generally very accurate; many of their pilots had thousands of bombing missions experience. The Army did what they had to do and often supported their own troops with helicopters, but these did not carry heavy weapons and were vulnerable to enemy fire. The AC-47 and the AC-130 were also being developed for CAS, but these also did not drop bombs.
Let me speak about bombing accuracy for a few moments, and I’ll start with the bottom line. The closer you are to the target when you release the bomb, the easier it is to hit. Having stated that fairly obvious rule, you needed to stay away from the target far enough to not get blown up with your own bomb or run into the ground trying to pull off the target, and yes, both things happened. Furthermore, the closer you got to the target and the ground, the easier it was for the enemy to shoot you down.
Tactically, this meant trade-offs. The safest way was to overfly the target and drop from altitude like the bomber. I notice that is the tactic the Russian fighters are using in Syria. I also notice their accuracy sucks. This tactic is not suitable for a single pilot aircraft without a bomb sight in the bottom of the aircraft and was not used for Close Air Support. And the accuracy is not nearly as good as that of dive bombing. The Navy’s A-7 was the only fighter with a computing sight used in Vietnam, and it was only used in North Vietnam during this period, so it was not used for CAS.
Many of you will remember “cornering speed”, shown here at the intersection of stall and max g. This is your minimum radius turn, with full power, and the speed that gets you away from the earth the fastest. In swept wing aircraft, it was too high. In the F-104 it is 450 knots. As I recall it was 420 knots in the F-4. The A-37 was designed to pull 4.8 gs at 320 knots, and it did it without losing speed. This allowed you to work much closer to the earth. The lower the cornering speed, the closer you can work to the target, and the less time you spend in the altitudes where small arms fire can reach you.
Another trade off was napalm. It didn’t explode so you could drop it really low without blowing yourself up. Nominal release altitude was 500 feet and accuracy was usually less than ten feet of error. It was very, very handy for missions where the troops were in contact with the enemy. It had a desirable side effect of denying the use of that burning ground for hours after the strike to the enemy. Cluster Bomblet Units, CBU, were also delivered from very low passes, and is also rarely used now. Of course, low passes means flying closer to the guys trying to shoot you down.
There are six variables in the bombing computation.
- Altitude above the target.
- Dive angle.
- G load. Nominal one g is desired.
- Yaw angle. This should always be zero.
It is clearly impossible to solve all these variables in your head, so what we did, back in the day, was pull up a pre-computed set of release parameters from the ballistics tables. For example, for a Mk-82 500 lb bomb, dropped from 2500 feet at a 30 degree dive angle and 320 knots airspeed, the proper mil setting was 130. So you set 130 in the sight, and then try to fly into an invisible funnel of all of those parameters exactly over where you want to bomb with a wind correction estimate. While the enemy shoots at you. And you talk on the radio and chew gum.
Our antique gun sight was little more than a fancy grease pencil mark on the windscreen. The pipper started with zero, the centerline of the aircraft, and that setting was used for strafe. The mils we so precisely set in it were fractions of an angle of depression below that centerline. I fondly think of them as mille-micro-give-a-shits, because it was genuinely like marking a line with a micrometer and then using an axe to cut it.
That mil setting is really a measure of the drag, or the drop the weapon will have below the velocity vector for the selected conditions. The velocity vector is easily found in the A-7 by a green triangle on the Heads Up Display, or HUD. It can be found in any aircraft by pointing the bird at the ground and watching for the point that does not move up or down, left or right. It is, after all, where you would make a hole if you don’t move the controls.
Let’s face it, the chances of hitting all those parameters while dodging enemy fire are damn small when you consider that your altimeter has lag and hysteresis errors, and your attitude indicator precesses to an unknown error every time you pull gs(spell out), which is every time you turn or try to evade that enemy fire. So you end up compensating. If you feel you are steep, you pickle a little high. If you are slow, you pickle a little low. It was the TLAR system. That Looks About Right. When you were making on average eight bombing passes every day, you became proficient. And of course you got to make corrections on the second pass, based on what you could see or what the Forward Air Control told you, perhaps for the wind that turned out to be different from your expectations. Given all these difficulties, the squadron quickly earned an accuracy within 15 meters. All things considered, a 500 pound bomb usually leaves a crater several hundred feet across, so hitting something within 50 feet was close enough for government work. The post war CHEKO (Contemporary Historical Examination of Current Operations) Report gave it a remarkable 92.1% accuracy rate over its five year operational history.
Returning to the basics for a moment, you cannot work very close to the target if you are moving fast because you have to pull out of the dive without hitting the ground, and those supersonic fighters could not fly very slow and still pull 4 gs or more. The F-4 typically dropped from 7000 feet at 500 knots. You can barely see the target from that distance, and the F-4 was known to be inaccurate. So inaccurate that it just was used only as a last resort for Close Air Support and was often an object of scorn among the Forward Air Controllers. Can I get an “amen” from the FACs in the audience?
The A-1, manufactured in 1945 was the most accurate aircraft we had in Vietnam. It bombed at 250 knots from 1500 feet. But we were running out of them. We gave 308 of them away to the Vietnamese and by 1973 we had none. What we needed was a straight wing attack aircraft.
Back to 1967. Motivated by the improbable combination of Jimmy Stewart and Barry Goldwater, the AF was coerced into reinvestigating the A-37 Dragonfly concept they had abandoned in 1955. Pushed by Secretary of Defense McNamara and all but ignored by AF senior generals, the A-37 was created from retired T-37s in the boneyard at Davis-Monthan AFB, AZ and spare parts. The wings were strengthened to carry eight hardpoints and two tip tanks. A 7.65 “mini-gun” was added in the nose as well as an air refueling probe. The engines from the T-38 were used, more than doubling the thrust from 1025 pounds to 2850 pounds each, and they were so powerful and so close to the ground that engine inlet screens were required for ground operations. They were also used when firing rockets. The gross weight was increased from 6,580 pounds to 14,000 pounds. A gun sight and a munitions panel were necessary additions and an FM radio was added for direct communication with the ground. A refueling probe was added to the B model, but never used in Vietnam. In fact, the crews were not qualified to do it. Also unused in Vietnam was the “seat tank”, a fuel tank replacing the unused right ejection seat. It provided 300 lbs of fuel for a 100 lb weight increase, and would all be used by level off.
The bird could carry 7,500 pounds of munitions compared to the 7,000 on the F-100. It was usually operationally equipped with two 760 pound drop tanks for extra fuel. This extra fuel allowed the A-37 to stay in the target area longer, often an hour if necessary, and even longer if one engine was shut down. The other fighters were good for only 15 to 20 minutes, and that was another reason the FACs and the ground troops loved the new little fighter.
The outboard pylons could carry a 500 pound store, plus we had the strafe, which was generally too small to be really effective. The A-1 could carry 8,000 pounds of munitions on 15 hard points, so we weren’t quite as good as aircraft built in 1945 , but we were faster and very, very easy to maintain and smaller and harder to hit. We bombed from 2500 feet at 320 knots so we worked closer to the target than anyone but the A-1. And if we used the snake eye bombs, we bombed from 1500 feet. I once put one of those in a cave mouth smaller than a garage door. The FAC went nuts. While I was at Bien Hoa in 1970-71 we had aircraft hit by ground fire at one third the rate the F-100s had there, probably it was because we were one third their size.
Another factor the former businessman McNamara doubtless loved was the cost of the bird. The A-37 ended up costing $161,000 per copy. Compare that to $700,000 for an F-100 or $2.4 million for an F-4. It also used about a third as much fuel. The A-37 had the highest sortie rate in all of Southeast Asia. During a test surge in April of 1968 the A-37 flew an incredible 6.31 sorties per aircraft per day over a three day period. Efficiency was in the package!
While I’m on the subject of cost, smart bombs were on the way to Vietnam. One way of increasing the accuracy of the supersonic fighters was to use a more accurate bomb. Well, a Maverick AGM-65 missile costs about $130,000 and it was being developed at the same time the A-37 was being built. It is not cost effective to use such a missile to take out a $3000 pickup truck, but it sure was high tech and cool and we bought thousands of them. On the other hand, a 500 pound bomb cost about $400, but you had to be able to hit the target.
The first A-37 was delivered to the 604th ACS in May of 1967 at England AFB, LA. By August, the aircraft was being tested in combat, the only aircraft ever so tested, straight into combat. Colonel Heath Bottomly, commander of the Combat Dragon Task Force, met with 7th Air Force commander Spike Momyer when he arrived in Vietnam, and his description of that meeting typifies the respect the A-37 received. Bottomly handed him his orders signed by the SecDef, McNamara, which stated that he was to be supported as he requested. Momyer dropped the orders straight into his waste basket and said, “Colonel, you will operate where, when and how I tell you to. Have a good war.” Bottomly returned to Bien Hoa and started operations slowly, working up to a sortie level of 48 per day from his 30 aircraft.
The A-37 was not tested in combat by test pilots, but a group of pilots from all disciplines. A few experienced fighter pilots, pilots straight from UPT, Undergraduate Pilot Training, former navigators and former bomber pilots. This is possibly an indication of how unimportant the AF considered this program. Thrown right into the crucible of war, this odd collection of pilots soon proved to be the most accurate bombers because they released their bombs closer to the target, closer to the enemy fire. Project Combat Dragon lasted for the first four months of that first year in Vietnam, and before it was over they were already getting improved model aircraft. The A-37A was replaced by the B model with still bigger engines. It was so successful that operations continued there until the A-37 was the only remaining USAF fighter in Vietnam in 1972. The USAF flew over 75,000 combat sorties in the A-37 and lost only 13 of the approximately 350 pilots that flew the bird.
Let me digress for a moment and talk about Forward Air Controllers. The first airborne FACs were in Korea, in the T-6. By 1967 the requirement to have been a fighter pilot had been relaxed (We were in fact running out of fighter pilots. The loss rate in Vietnam and the 100 mission tour was causing involuntary second combat tours for lots of pilots. Operation Palace Chase was chasing all the staff pilots out of the staff and into Vietnam where the older Lt Colonels were usually useless. It also permitted bomber pilots like me to get into a fighter!) FACs could now come straight from UPT and go into the O-1, O-2 or brand new OV-10. Ground attack was now done almost exclusively with an airborne FAC in control. .
I remember going through A-37 training at England AFB, LA. The instructor explained to me in no uncertain terms that I wasn’t a real fighter pilot or even in TAC. When I got to Bien Hoa, an F-100 staff weenie looked at my records and said that I already had all the decorations I was going to get since I already had a Distinguished Flying Cross from my 172 B-52 missions. He was right; no A-37 pilot got a Silver Star or above while I was there. The 604th was now re-designated as an SOS, Special Ops Squadron, and it was treated like the red-headed bastard child that nobody wanted. But I got a break. The variety of pilots in the unit allowed me to progress to instructor pilot; something no real fighter pilot unit would have allowed a bomber pilot to do and I remain intensely proud of my 205 fighter missions.
Cessna built 577 A-37Bs in all. 284 were given to the Vietnamese and only 27 of those made it to U-Tapao Thailand on 30 April 75 when the North Vietnamese overran Saigon. Most of the rest were given to the USAF Reserve forces except for one squadron at Davis-Monthan AFB AZ and a few assigned to Edwards AFB, CA. These were used to chase the A-10 during its test program and also at Test Pilot School where they were used as an introduction to spin training. I was delighted to get back into the cockpit as instructor and chase pilot there! Today there are a few privately owned A-37s still flying, both here and in Australia, but most of them were given away to South and Central American countries, plus Korea and Thailand. Most of these are now exhibits on poles at museums.
The Dragonfly never received much credit from the Air Force. The staff was trying to move forward with technology, not backward. But the Army, the people on the ground, well remember the A-37s answering the call with devastating close air support. It was an extremely successful program, and led directly to the development of the A-10.
The A-10 filled the Army’s need for Close Air Support. It carried 16,000 pounds of ordnance on 11 hard points and had a 30 mm Gatling gun cannon that would put a hole in a tank. This was a manly load! But the AF staff still did not care for the CAS mission and only bought it to stop the Russian tanks in the Fulda Gap in Europe. The F-35 is not slated for that mission; it is really a replacement Wild Weasel, a ground to air battery killer designed to work with the F-22 in the integrated battlefield of the future. Personally, I have doubts that using a $100 million dollar aircraft for that role will prove cost effective. In reality, there is no updated CAS aircraft coming, but just last week the GAO delivered a scathing report to the AF that will keep the A-10 for the foreseeable future.
Our A-37 motto was: “The smallest fighter, the fastest gun!” It was certainly the little airplane that could. Personally, I feel very fortunate to have escaped SAC and gotten to fly the bird in combat! It has been said that a man will have no love like his first fighter aircraft, and while maybe I can’t go that far, I certainly understand the feeling.
So I have given you the brief history of the A-37. Created from spare parts and bone yard aircraft in the middle of a war, it remains unrecognized for its accomplishments.
Let me digress a moment and say that the division between the Army and the AF over CAS is fundamental and ugly. The AF believes its mission is air superiority and CAS aircraft do not contribute to that. The beauty of this story is that American ingenuity was able to cover over the problem swiftly and inexpensively. Personally, I think the way to close that divide is to give the Army some jet fighters. Unfortunately, the Army declined taking the A-10s in February of 2015 because of the budgetary hole that comes with them.
I’d like to close with a quote from the 380th Air Expeditionary Wing mission statement that puts it into perspective for me. “The mission is an 18 year old with a rifle. All else is support.”
If you decide you want the book of stories from the A-37 personnel that has been circulating, just send me an email and I will email you the order form. They are $30 for hardcover and $20 for soft cover.