One of the challenges when picking up someone else’s project is trying to decide where to begin. Especially in a one of a kind project as far along as this is, that can be a big question. So I took a little time to review all the documentation that came along with the project as well as look over the fuselage. This included an initial study of both the stock Rutan Defiant plans and the changes that Brian has made.
From what I gathered, the general task list or major project categories remaining to be completed are:
- Front and Rear Engine Installation
- Engine cooling and induction systems
- Overhaul both engines
- Finish Nose gear actuation
- Finish Rudder Actuation
- Mount the Canard
- Flight control trim systems
- A small amount of finishing work in select locations
- Electrical system and avionics
- Then there will be all kinds of things like upholstery, paint, etc which will be well after the airplane flys.
From my initial review, I was able to determine that I have to spend a lot more time looking over the plans, Brians drawings, and measuring the fuselage. I will need to do this to answer questions like:
- What coordinate system and airframe references did Brian use?
- The airplane is larger than stock, so did he stick with normal Defiant butt lines/water line/fuselage station measurements?
- What is the level reference for the fuselage in pitch and roll?
- Brian was planning on changing from electronic to hydraulic nose gear actuation. Arleen was able to tell me this was because he was concerned the linear actuator wouldn’t be able to provide the force required. So I need to analyze if we can stay with electric.
- Many Canards use an electric actuator, and I would prefer to stay this course if it is reasonable. Hydraulic would just add more weight and complexity if it is not required.
- What was Brian planning for cooling and induction air?
- Some of this is evident, but not all details. So I was able to call in an expert to help me make good decisions. Dave Anders, of worlds fastest RV4 fame, helped me to determine what my plan should be going forward as far as air needs for each engine.
- Brian’s main gear is very tall. There was a plans change that required cutting 4″ off the bottom of the gear to get the right wing/canard incidence on the ground. This affects rotation speed and thus takeoff distance. It doesn’t seem that he did this. So did he fix it by making the nose gear longer? This accomplishes the desired result, in a different manner.
- Right now the main gear to fuselage fairings are bonded in place solid. There doesn’t appear to be any provision for relative motion between the fuselage and main gear from gear flex or takeoff/landing/taxi loads. Was there a weak spot built in to accomplish this? Or do I need to cut a slit in the fairing to prevent cracking of the fairing? I’m betting I will need to cut a gap and Brian just didn’t get to it yet.
- How far along is the electrical system, what schematics was Brian using, and what items are installed already?
- The Rutan plans shows a nose gear shimmy dampener, but with the new gear design, I don’t see a provision to attach one. Is it internal to the custom gear strut like many other homebuilt designs?
These are just the initial list of some of my questions to give you an idea of the scope and detail of the forensic investigation I am trying to go through to keep the project moving along. I have the answers to some of the questions above, and am working on the rest. New questions pop up all the time as well.
For now, I have decided to start work on the engine installations. I have decided to start there for 2 reasons:
- I like the setup I used on Betty and essentially both engines will be a copy of that except one is a normal “pull” engine. So it is a known pathway.
- I am going to have to send out components from the engine for NDT (non-destructive testing) and that can take prolonged periods of time. I don’t want to be ready to fly the airplane and waiting for a case to be zyglo-ed. So I want to get as much of the installation complete and as many hoses/wires/harnesses/baffles/etc fabricated, fitted, and installed. Then I will remove the engines, disassemble, send parts out, and overhaul the engines.
For those of you wondering, the engines are parallel valve Lycoming 360s. The front is an A2A, the rear is an A4A. I am going with Airflow Performance fuel injection and PMags on both engines.
Stay tuned for the next post where I will show you some of the changes to the engines and the start of the cooling systems.