Up and Around
12822 Tarrytown, San Antonio, TX 78233
Family and Langley
My late Aunt Albertine was most musically inclined. She even married the director of music for the old Waldorf-Astoria in New York City in the 1920s. It was only natural that all their children would become accomplished on more than one instrument.
One son, however, had a penchant for physics. This son, Edward, graduated in the midst of the Depression of the 1930s. With no job in sight, Edward took a government‑sponsored physics exam and scored second highest in the nation. From the employment offers that ensued, he accepted a position with the original NACA (now NASA) at Langley Field, Virginia.
One of Edward's associates in that early wind‑tunnel engineering group had a sister, whom Edward before long married. The brother‑in‑law was named Abbott, and my cousin's full name was Edward Albert von Doenhoff. I wish I could claim all sorts of knowledge gleaned from my association with Edward, but the truth is we met only twice.
My cousin and Abbott continued their research and together wrote the original paper published on the laminar‑flow airfoil. To show you how small the world is, I was relating the above story to Frank Parmenter at our Tri‑City MAC Christmas party one year, and his reply when I finished was, "Yeah, and my wife typed it for them!"
Brainbusters Club and Parmenter
Also among those at Langley were Taibi, Hull, Blanchard, Parmenter, et al. The Brainbusters Club, which was started in that bygone era, recently celebrated its 50th anniversary. Frank Parmenter was the group's first president and, according to him, the reunion was a huge success.
Ed Manthey, Zeniths, and Buffalo
Frank, who was raised in the Chicago area, immediately remembered the name of Ed Manthey. Ed had written to Up and Around upon seeing the photo I ran of Smilin' Jack Kaufman with his Lackey Zenith. In writing, Ed related that he not only knew Bill Lackey well but also assisted in the construction of the original model. He went on to say that when flying with the Buzzards Club, he won the Senior division at the Detroit Nationals in 1938. They started with Baby Cyclones for power, then tried Brown Juniors, and finally Super Cykes.
Parmenter immediately identified the models. Fellow clubmate Russ Snyder said, "Yeah, things went out to Buffalo the next weekend," — both Zeniths back flying at the field. Both models were still flying well with Super 60s for power. Rosie placed fifth in the 30‑Second Antique at the 1992 SAM Champs.
Old‑Time Free Flight — Safety
While I'm on the subject of Old‑Time Free Flight (OTFF), a safety problem needs to be addressed.
- At a normal AMA Free Flight meet, make sure the cars are a minimum of 100 feet upwind from the flight line.
- In events that use the ROG (rise‑off‑ground) mode of launching, the model flies directly at the line of cars. Launch sites must be located with ample clearance to the front and rear — 300 feet minimum — and side clearance must also be considered.
- When you're test‑flying with only two or three cars present, the safest launch site is probably right next to the cars.
Measuring Port Timing and Blowdown
There have been many letters asking about port timing and pressurized fuel systems. The term "blowdown" has caused some confusion. Simply stated:
- Blowdown refers to cylinder port timing.
- The blowdown period is the difference, expressed in degrees of rotation, between the total time the exhaust port is open and the total time the intake port is open.
- To know port timing on a particular engine, you need a method of measuring shaft rotation.
To make a simple degree wheel and measure port timing:
- Use a 360° plastic protractor with a solid center so it can be mounted on the engine shaft.
- Make a pointer from a piece of .040 music wire and mount it to the engine lug.
- Rotate the piston on the downstroke until it is at the top edge of the exhaust port. For accuracy, remove the head and shine a light down into the cylinder to match the top edge of the piston and the exhaust port. Set the pointer to zero when the two edges coincide.
- Rotate the piston down through Bottom Dead Center (BDC) and back up until it closes the exhaust port again; read the total exhaust‑open degrees on the wheel.
- To check intake port timing, remove the back plate and direct a beam of light up into the bypass(es) and read the intake timing similarly.
Example: if exhaust is 140° and intake is 130°, blowdown = 140° − 130° = 10°. For a good Pattern engine (CL or RC) a blowdown period of about 7° to 12° is desirable.
Pressurized Fuel Systems
There are several ways to pressurize a fuel system; the two most often discussed are crankcase and muffler (header) input. The main reason to use pressure is to allow a larger venturi and thereby gain more power.
Crankcase pressure comes in two types: timed and untimed.
- Timed pressure: the impulse to the crank is made only while the rotor port (shaft or disk rotor) is open, not when rotation is in a suction mode. Thus, only positive impulses enter the pressure line. This system can make the needle‑valve setting extremely sensitive, sometimes allowing only a very small movement from too rich to overlean.
- Untimed pressure: the fitting is open to the inside of the case all the time. This system can produce more pressure than needed and can allow raw fuel to reverse‑flow back into the engine, causing a badly flooded condition.
A practical solution to an overpressurized fitting is to reduce the hole size in the pressure fitting by soldering it down to the required diameter. Select wire of the required diameter, insert it in the hole, solder around it, then remove or file it back to the desired opening.
Nationals Stunt Engine — the .33 S
I remember one qualifier who flew with a U‑Reely and did most of his pattern with 80‑foot pullouts. Neither Bill Cummings nor I even qualified. This is not sour grapes — I didn't really deserve to qualify; but Bill did. I later spoke with Walt Good, the AMA president, and promised I would never compete again if he would let me run the Nationals Stunt events. Family and job commitments prevented my fulfilling that promise in 1959, but that's a story for another time.
Here's the engine story: by July 1958 I was in Tulsa, Oklahoma, deeply involved with the electromechanical design of the pilot trainers for the then‑new Boeing 707. I had made the trip to Chicago in search of a special counter for one of the flight instruments; the Nationals was just a sidelight. I had been doing some testing for Hi Johnson, and he prevailed upon me to put his latest .35 in the old '57 winner.
Practice went from bad to worse. The .35 would come on "song" and run wide open, no matter what I did. In my last official flight the glow plug went out. The prop balancer then jumped on the plug; the plug burned out and blew completely out of the engine. The threads in the head were stripped.
That night Hi tore the engine down to check it out. Taking new parts, he assembled a new engine using a .35 cylinder assembly and case but a .29 shaft. This gave a .33 displacement, and it was bolted into the old black Nobler. The next morning at a practice area Hi put a 7 x 5 Y & O prop on the .33. The engine was started with instructions to do lazy eights if possible. Some 15 flights later we had progressed from the 7 x 5 to the 10 x 6 regular flying prop. I never ran a better Stunt engine, and Hi marketed the engine as the .33 S. I still think it was his best Stunt engine.
Miscellaneous Notes and Contact
- Thanks to all who identified the "Flying Priest" for me. His name is John Quimby, of Elyria, Ohio. Are you still flying, Father?
- I will accept phone calls between 6:00 and 10:00 p.m. CST. Please don't call during business hours to BS about modeling — I have a business to run.
- For those who have written and sent SASEs, you know I answer my mail.
- I have added a fax machine at (512) 665‑2021. It will answer after about six rings; hang up after five rings and you won't be charged if I'm away.
Transcribed from original scans by AI. Minor OCR errors may remain.
