Category: Blog

The Hurricane

In late August 1979, I had to fly down from St.Thomas to Grenada and back in one day. This would be almost 6 hours of flying, all over open ocean. I used to transport passengers and cargo in my Aztec, in a Part 135 operation, principally between those two islands.

Satellite View Showing Trip From St.Thomas to Grenada

My Aztec, N1209U, was a fine one. Her engines had been balanced part for part during their overhaul, and she had three bladed props. The result was the smoothest piston powered plane I have ever flown. She really felt like a turbo-prop.

N1209U on the ramp in Grenada

I took off from St.Thomas, not expecting any special weather, but when I was abeam Martinique, (roughly two thirds of the way, and 100 miles out to the West) the there was an area of cumulo-nimbus that was not in the forecast. I was able to skirt it , leaving it on my left,to the East. The flight was about 520 miles as the crow flies, and I used to fly like the crow in my B model Aztec.

In the afternoon at about 4 o’clock, I took off to go back NorthWest to St.Thomas.  As I passed St. Vincent, 75 miles along my path, I saw ahead a solid wall of clouds, from the surface to maybe 35,000 feet. It extended from East to West, as far as my eye could see. It seemed to me I might be able to get around it on the western side, so I deviated a little to the left. Eventually, I was going straight West along this solid wall of rain and cumulo nimbus cloud.

LOCATION AT THIS POINT #1

I was in a bit of a bind, because all the airports behind me closed at sunset.There would come a time when I could no longer turn back, because there would not be any lit airports I could reach. I worked it out in my head, and decided on a cut-off time to make my final decision. If I had not been able to start around the western edge of the clouds by 6 o’clock, I would have to turn tail.

As I mentioned, it was 1979, and there were few usable VOR’s, so most navigation was by compass, and sometimes broadcast stations on my ADF. The only VOR’s along the route was at St.Croix, with a range of about 100 miles.

As luck would have it, just about my turn back decision time, I was able to turn about 45 degrees right, so I made the decision to press on. Now my return to Grenada or St.Vincent would no longer be possible, and I would have to make it to a destination to the North.

LOCATION AT THIS POINT #2

What I had not anticipated, was that the storm itself was not stationary… it was progressing relentlessly West, further away from land, which was becoming North or even North East of me. I had no way to back up, my direct course was blocked, and the blockage kept moving further West, and pushing me with it.

I had just finished reading a book by Peter Garrison, “Long-Distance Flying”. It would save my life on this trip. In his book, he talked about maximum range and leaning. He had experience… he had flown his Melmoth homebuilt from California to Japan

“Long Distance Flying” by Peter Garrison

Darkness descended, and I continued along the edge of the solid bank of clouds, way out of range of any navigation or voice communication. I was alone in the middle of the ocean, going the wrong way, and with a limited amount of fuel.

But in his book, I remembered Peter saying that maximum range was obtained at a speed a lot lower than what the aircraft’s manuals claimed. The manual would say “55% power” but actually, best range was at a speed about 10 or 15% above best glide ratio. Technically, the best glide ratio should be the best range, except it would mean running the engine and props at way less than their optimum efficiency. Somehow, I decided that 118 mph was the speed I needed to go to. I had been gradually climbing, so I finally reached 13,500 feet, full throttle, 1800 RPM. I had mixture leaned so far that the engines were really rough, and the airspeed indicated 118 mph. At this speed fuel consumption was 6 gallons per hour per 250 hp.engine.

My stomach churned, but all I could do was press on. I was dodging between towers of Cumulo Nimbus’ clouds and actually edging a little towards the center of the storm, to get closer to my desired course. It was a beautiful clear night above the clouds, but I felt very cold and lonely. amazon cloud . My stomach ached from anxiety. Me and my trusty Aztec, alone in the middle of nowhere.

LOCATION AT THIS POINT #3

About four and a half hours after takeoff (my estimated fuel endurance had been four hours), I started to hear faint voices on the VHF… speaking Spanish. I tried to communicate, but got no response. By this time I was able to head North East, which was heartening, although the voices I heard were coming from Santo Domingo (Dominican Republic) 330 miles west of my intended destination.

Final Route Compared to Planned Route

Eventually, I was able to talk to San Juan (Puerto Rico). They had already figured out that I was down in the ocean, and were preparing to send out rescuers. My fuel was supposed to be all gone an  hour ago. But when I drew abeam San Juan, less than 100 miles from my destination, I still had what looked to be 1/8th tanks, so instead of landing in there, I continued on to St. Thomas, my home field. After all, it was all down-hill now, as as I was still at 13,500 feet!

I landed at 10:30 at night, instead of 6:45. Later I learned that a hurricane had developed right on my course, unpredicted. I had flown 6 hours and 30 minutes on a route that normally took 2 hours and 45 minutes!

The lessons:

1) Don’t do the job I was doing. You will likely die.

2) Read Peter Garrison’s “Long Distance Flying”. It saved MY life!

3) Don’t fly like I used to. You will likely die!

-Robin Thomas

Over 5,000 Hours of Flight Time and Founder of Laminar Flow Systems

My first experience modifying

My first experience with modifying a plane was in 1965. I had just bought a Lockheed AL 60-b, which was a rare large single engine, kind of like a Cessna 208. It was supposed to cruise at 150 MPH but it only did about 107 indicated, which fell real short.

Lockheed AL 60-B (Photo from: http://www.jitterbuzz.com/lockheed_patents.html#stogy)

So, I wrote to Lockheed and they sent an engineer down to Mexico City to help find some answers. His name was Tom Lawrence, and he spent about 3 months working with me on the project. We eventually got it to cruise about 14 mph faster, and that was all that could be done, short of adding pants or putting an intercooler in the turbo system.

I was experimental by nature and had modified everything I had ever owned… sometimes successfully.

What we did on the Lockheed was to remove all the pan head rivets on the upper side of the wing, and substitute them with countersunk ones. There were over 2000 of them. I was happy with the result.

Pan Head Rivet vs. Countersunk Rivet (Pop Rivet)

Nothing more happened in that that field until I bought a Seneca I when I was flying air charter out of St..Thomas, US Virgin Islands. I thought the Seneca would perform as advertised, and again, was cruelly disappointed that it did not. I could only get 157 mph economy cruise, when I was hoping for at least 20 mph more. My previous Piper twins (a Doyn Apache and an Aztec) had done exactly as I expected, or more, so I started to fret about the Seneca. I was especially disgusted to read that the Partenavia twin, with exactly the same engines and the same size fuselage was about 20 miles an hour faster than my Seneca, even though it had fixed landing gear!

My Seneca

Then I saw a Partenavia, and the reasons became clear. It’s wing was glass smooth on the upper surface instead of covered with rivets and screws as the Seneca’s was. My previous experience with the Lockheed suddenly became relevant. I was desperate for a better cruise because most of my flights were long distance… over 500 miles per leg, and I was getting bored. I decided I had to act, so I bought a can of Bondo and some flashing aluminum.

A Partenavia (Photo from: http://commons.wikimedia.org/wiki/File:D-GHAN_Partenavia_p.68_Victor_(P68)_01.JPG )

By carefully fairing the upper surface of the wing, I got an increase in cruise speed of over 8 mph, and my future as a modifier started from that moment. I knew if I could get 8 MPH on the top of the wing, simple things like gap seals and hinge fairings would give me another 7, and that was enough with which to get started in business.

I spent a year testing all kinds of bits and pieces which I made. Seventeen different mods in all. During that time, we down to eating roadkill! Then I presented my results to the FAA. Nothing happened for like 8 months, and I was even more frustrated. But one day I got a charter from Grenada to Nassau, so I picked up my wife in St.Thomas on the way, and continued to Virginia, where we had a son to pick up from his summer vacation. By chance, an old friend of my wife’s was very high up in AOPA and she introduced me to the head of the Atlanta ACO, by telephone. We flew down to meet him the next day, and he was incredibly helpful. He in turn introduced me to Piper’s chief of structures, with whom I had lunch the following day in Vero Beach. It seems everyone wanted to help me, because I was nice, naive, and so enthusiastic… “throw that good dog a bone”.

Four months later, the FAA flight tests were all passed, and I was issued my first STC… for the Piper Seneca.

Click here or visit this link to see what modifications LFS can offer for your aircraft today: http://www.laminarflowsystems.com/#!products-2/cayx