Aerodynamic Drag

Here's an interesting video from a lecture given in the 50's by an MIT professor about aerodynamic drag and why it's important to have an airfoil shape when you're going fast. The RV series of aircraft are about 50 knots faster than the equivalent production aircraft with approximately the same size motor and weight due to careful drag reduction. Don't you just love youtube?

Pitot Line And Pushrods Installed

Got the pitot line installed which will connect to the pitot tube. It measures how much pressure is being pushed in the front of the tube and compares it to the static pressure in free air on the side of the aircraft. The calibrated difference outputs to the airspeed indicator while the static pressure outputs to the altimeter and vertical speed indicator. If you didn't recognize it immediately, it's the curved tube with the big blue nut at the bottom of the picture below.

You can also see the bellcrank with the two pushrods attached. An elegantly simple system. The larger pushrod connects to the bottom of the stick in the cockpit. The smaller one which is going up in this picture (aft when the wing is level and not held in a jig) attaches to the aileron.

Here's a youtube video with a lesson on pitot static systems.

Left Aileron Mounted

Here, Austin and I have mounted the left aileron. Yup, lots of fingerprints. It had to come on and off multiple times to get the spacers and washers just right. It was a near perfect fit. We only had to add one "L" or thin washer beyond what the plans show which was not bad as the instructions said to add washers or make spacers as required.

Started On Aileron Installation

I decided to install the ailerons first and then check the flap hinges for spacing before drilling them. I didn't want to order a new hinge if the spacing wasn't correct plus all the trouble of drilling out rivets, etc. Below, I've finished one of the aileron to stick pushrods. These will connect to the bottom of the stick in the cockpit and then through the wings to the bellcranks in each wing which will then connect to pushrods which will control the ailerons. Kind of like Dem Bones: the kneebone's connected to the thigh bone.... Be sure and click on the link and wait for the music and scroll down a little to watch the skeleton dance. Funny!

I added padded magnetic jaw pads to my vise. I had to ream out a brass bushing for the bellcrank and it was much easier with these plus little chance of crushing the soft tubing. I used them on the pushrods above as well. After having used the bench vise for just a couple of days, I now consider it a tool necessity!

New Vise Plus Work On Flaps

Here's a picture of my new bench vise with the flaps in the background. I've been trying to find a good vise at a reasonable price on craigslist or ebay for about 6 months with no luck. The flaps require a bend on two pieces of thick aluminum and a vise like this one will make it much easier. This was the only one left at Home Depot that was Wilton brand and it was only $21! It was made in China but under specs for Wilton so I'm hoping the quality is a little better that the usual China junk. The old bullet style Wiltons on ebay go for hundreds. I made this one detachable by epoxying nuts into the bench. The white stuff below the vise on the edge of the bench is the epoxy with the nuts inside.

I'm making slow but steady progress on the flaps. Part of what's holding me up is understanding how to attach the flap hinge. The written plans say to attach one half of the hinge to the flaps now but the plans have a note to move both sides of the hinge forward or aft to align the flaps with the ailerons. Sort of a Catch 22 thing. The RV forum wasn't real clear, either. Hmmm?