It's not all spanners and screwdrivers

Over the past four weeks we have been making lots of progress on the build, however if you looked at the fuselage it's almost like nothing has happened. So what has been going on? Logistics, paper work, and buying the engine!

It's not all spanners and screwdrivers when it comes to building an aircraft, as there is a lot of paper work and research involved too - especially when you're deviating from the plans to modify the aircraft. As it stands we have the following modifications with the LAA:

  • Raven wings/increased aileron length
  • Wolf Canopy
  • Wolf Cowling
  • Simplified fuel system
  • Reshaped rudder and elevator

Each one of these modifications requires a mod form to be sent to the LAA, so that it can be discussed and ultimately either approved or rejected.

The modification which has caused the most work at present is the Raven wings, which (amongst other changes) increase the aileron length by an extra rib bay. I first emailed Raven Aircraft back in March 2015, seven months before I even committed to building this aircraft, just to see if they would do a wing kit for the S-1-11B here in the UK. Their initial response was not positive.

They had previously made a kit for the S-1SS to LAA specification (now fitted to G-FORZ) which took up a lot of their time, and didn't have the appetite to go through it again for the S-1-11B. Eight months later, now that I have bought the fuselage, I decide to ask again. This time, with me offering to act as the middle man between the LAA and Raven, things are far more positive.

This increase in aileron length will put the roll rate at roughly 380 degrees a second, and give me more control authority at lower speeds. However, it will also increase the stress within the wing, and such change needs to be analysed properly to ensure the increase is not going to pull the wings (and my face!) apart. Below is an animation of the wings being loaded up as the ailerons are deflected:

Thankfully this animation is exaggerated slightly and they wont bend that much in reality! The analysis is on-going but feedback over the weekend is rather positive and we're hoping to get the go-ahead this side of Christmas.

The engine

Mentioned briefly in our previous progress update, we've had the initial go-head to purchase the engine that will power this incredible biplane!

It's a Lycoming AEIO-540-X built by Barret Precision Engines, a company which specialises in building high performance engines and have built many engines for various Red Bull Air Race aircraft.

Our engine started life as a IO-540-C4B5 that once powered a Piper PA-23 Aztec, and has now been fitted with Combustion Technology 10:1 compression pistons, BPE's cold air induction system, and an Airflow Performance FM-300A fuel injection system. With various other mods & tuning, this engine will produce over 300hp. Comparing that to the stock engine which would produce near 260hp, she's going to be one powerful Pitts!

We can't wait to hang it on the front for the first time. I just hope there's room in the garage...

What's next?

One of the other modifications that we are planning is to significantly simplify the fuel system. This is because the stock plans call for a system that involves two fuel cut off values, tubing running up & down both sides of the fuselage to the cockpit, and underneath the seat!

As we are planning to use the Dynon Flightdek D180 and a fuel transducer, we can remove all the tubing related to the fuel sight gauge as that will be calculated and displayed on the Flightdek D180.

A remote fuel cut off valve will allow us to keep all of the fuel system well away from the cockpit, and down near the firewall instead. This will make life in the cockpit far safer, as I wont be surrounded by metal tubing and fittings that could spring a leak. Keep it simple, keep it safe.

With some parts arriving from the states very shortly, the next few weeks and over Christmas should be a rather productive period. Keep an eye out on here and our Facebook page, Building EWOK, for more updates.