SPOTLIGHT ON

The NEED for SPEED

I'm honored to feature master builder & designer Merlyn Graves, magnificent AVRO VULCAN

ducted fan jet as the first subject in "The NEED for SPEED".

Merlyn has graciously allowed me to print the article that he wrote about this incredible model.

Most modelers always have their “Dream Aircraft” in mind that they hope to build someday. Mine was the Avro Vulcan Bomber.

I started on this project around 1987. Using an old “Profile Publications” issue of the Vulcan and sizing Byron Fans, yielded a 1/10 scale model that would have a wingspan of 136” and a fuse length of 121”. With the help of my long time flying buddy, Vince Maryanski, we cut parts to create a one time fiberglass mold and I began to assemble the parts. After several weeks, the plug started to take shape. Then as it sometimes goes, I got involved in other projects and temporarily put the Vulcan on the side.

Skip ahead 13 years. As I started into the project again, I discovered that I had incorrectly joined the halves together with a result of a lot of anhedral being in the wing. The whole thing would basically have to be redone so I decided to go with my strength and build it from wood.

Using Auto Cad, I generated a set of “shop drawings” and construction began in August of 2000. I decided to power it with four Dynamax fans on OS91DF engines. The size of the airframe would make handling difficult so I decided to make the vertical-stab/rudder, the 36” nose, and the wings outboard of the fans all removable.

I love building from scratch and the Vulcan has definitely been the most challenging and satisfying aircraft I have ever built. With the fans occupying most of the entire inside of the fuse/wing section, there was no way to build in a main spar as on a typical wing, so I just played it by ear as I went along and tried to incorporate enough structure to transfer the loading of the outboard wing section to the fuse section.

After 1-1/2 years the model was completed. I calculated the CG but to verify it, I built a 36” electric model that required a 2” forward CG correction. I had hoped to bring the weight in at around 65 lbs., but was shocked when with fuel it weighed in at 90 lbs. The first flights would definitely have to be off of a hard surface runway.

May 10^th was a sunny day in the 50’s with a 16mph wind straight down the runway. After getting everything assembled and all four engines tuned in, we rolled out to take off. Having 5700 sq/in. of wing and a wing loading of 37 oz. sq/ ft., I guessed that it would rotate in 350-400 feet, so I taxied out about 200 ft. and turned it into the wind. It accelerated like a hot rod and rotated in about 175’. As it reached me, it lifted off and was climbing with authority. By the time the first circuit was completed it was trimmed out; requiring only 2 clicks of up and 4 clicks of right elevon. On the first low pass I was amazed to see that it was going easily in excess of 100mph. On the second pass I put it into a huge loop that it flew through with no problem. The downwind pass included rolls. It exceeded all my flight expectations by a wide margin. The CG adjustments made from the electric model were right on the money. The landing approach was made at high speed and it greased in with all four running. The brakes worked well and it stopped in about 250’. I was ecstatic.

Subsequent flights have turned up a few structural design problems. Those have all been corrected with minor changes. I have been having a lot of engine problems and am still trying to work them out and keep four running. It has flown on three, two, and even one engine (nose down and heading for home) and has proved quite stable and predictable in emergency situations. It is unfortunate that the AMA weight restrictions for turbines are 55 lbs. as it would be a great candidate for turbine power. Maybe someday….

January 13, 2004

Eighteen months have passed since this article was written and I now have 40 flights on the aircraft. In the 42 years that I have been flying RC this is the most thrilling aircraft I have ever flown. Each and every flight is a pure adrenalin rush. When I am not flying it, I am daydreaming of my next flight. Since I am restricted to flying off of a hard surface runway, I don’t get to fly it as much as I would like. Each flight requires a trip out of town to an event with at least 800’ feet of runway for landing. Now that I better know the flight envelope, I could fly off of a 400’ strip, but it only takes that one mistake on landing, and I zip by at 75+ mph and run off the hard surface. That usually results in damaging the nose gear, so I limit myself to longer fields. At Superman in 2002, the radar recorded the following data.

Take-off speed—23mph

High speed pass—147 mph

Landing speed—42 mph

All the engines problems have been solved and I rarely have a “flame out”. Generally it only takes about 3 minutes to start it up and taxi out. The change in the AMA “55#” rules, now allows me to fly anytime, instead of alone as a demonstration, which makes it much easier to attend IMAA events.