Thank you for all the kind words and votes of confidence.
Maiden flight update and a clarification . . .
First, the clarification: This airplane is not the Walter Umland kit. It is plans-built from plans found here on StuntHangar and drawn by Bob Krueger with input from Tom Lay:
https://stunthanger.com/smf/open-forum/dual-purpose-plane-for-profile-and-classic/msg557466/#msg557466 . But I would offer a word of warning: the plan as printed in its current pdf format is about 5% too small. I found that out when I printed the scale at the bottom of the plans. That was not a problem for me because Adobe allows scaling pdf’s to any scale. Once the correct size was printed, sawdust ensued!
The engine was bench run for a total of 150 minutes (yes, that’s 2-1/2 hours) with 1 gallon of fuel – 10% nitro with 11% castor/11% synthetic mix. From the bench I knew it would consume 1 oz per 1-1/2 minutes run time, so I had a rough idea of how much fuel for a 5 minute flight.
Now the maiden flight update: Just three words --- What a Joy! I got in 5 flights this morning, all with 3-1/2 oz of fuel in the 5 oz tank. The first 2 were a little rich so I got only about 4 minutes flight time. The engine speed was 9000 to 9200 rpm on the ground, good enough for me to do gentle climbs and dives and, with enough momentum, an occasional wingover. Flights 3 thru 5 maintained the 3-1/2 oz of fuel but with an increased speed of approximately 9600 to 9700 rpm and a resultant flight time of 5 to 5-1/2 minutes and lap times of 5.2 to 5.25 seconds. This is where the joy comes in! I gained enough confidence in the airplane’s and engine’s ability to do inside and outside loops, triangles, squares, inverted flight, lazy 8’s (both horizontal and vertical) and a one 4-leaf clover. In all, a pretty good day and with enough info to make a few trim adjustments:
- The best engine runs were at 9600 rpm as measured on the ground.
- The outboard wing is a flies a little low. A flap tweak will fix this.
- I could tell from the inside loops that it was a little nose heavy (I wanted it that way for the first flights.) I built an adjustable tail weight box in the rear of the fuselage which will get used now.
- Take-offs and landings were very smooth. The airplane glides extremely well.
- Good line tension through all maneuvers.
- Inverted flight seemed good, but I may lower the fuel tank by 1/16” (the C/L of tank is currently 5/16” above C/L of venturi.)
- 3-1/2 oz fuel yields a flight time of 5 to 5-1/2 minutes. I will increase to 3-3/4 to 4 oz to assure I don’t get fuel starved in the overhead 8 or clover.
To answer a few earlier questions:
- I know a little of the Trophy Trainer’s history, but just what I have researched here on StuntHangar.
- The US Navy used green tails on airplanes flying from the USS Ranger. (I don’t have a family tie to the Ranger, I just liked the green color contrast! I do have a tie to the USS Wasp but they used black tails later in the war. I figured green would present better in the air.)
- The plan was to have an airplane that could compete in multiple events. I hope I can have this ready in time for Brodak.
Topic: Trophy Trainer (Read 1240 times)