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23 JUNE 2007 Main Gear O-Rings

While I had the plane sitting outside, I developed a leak at the bottom of the strut. Of course, this was the ONLY O-ring that I didn't replace when I had the gear dissasembled a couple months ago.

The bright side, the gear has been sitting for about 6 weeks without being cycled, it still had about 500 psi of down pressure.

These photos show the O-Rings and spacers, I'll add the part numbers and orientation when I get a little time with the Corel Draw program.

A trip to the Parker store, and I got "ALL" new O-rings, spacers, and the end wiper. Everything will be replaced when I reassemble the gear.

WELDING STRUTS

In the original early version of the gear assembly, the internal alignment tube, (photo 2 above), the main tube side brace support, and the spar plate trunion support ring are held in place by an aviation grade structural bonding agent.

SO, Leave it alone, or have the components welded??.

I talked with JD at Infinity Aerospace a couple times this week. There are two cases of the bond failing, however, its concievable that both of these failures could also have occured even if the parts were welded.

I visited my local welder a couple times this week and showed him the two pieces I need to have welded. We reviewed the process he is going to use, and he knows what the final product is supposed to look like. So today, I made the decission to go ahead and have the two components welded, the internal alignment tube, (photo 2 above), the main tube side brace support.

Although it would have been nice to also weld the mount plate, its to late as the plate is mounted and I don't want to remove it. However, before I mounted it in place (last year) I did place two roll pins in the trunion pivot so that if it did break loose, the pins would hold it secure in place.

I'll post some before after photos after he's finished.

17 JUNE 2007 Happy Fathers Day

Mounted the oil door on the top fuselage.

Disassembled the plane and moved it back into the shop. The purpose of assemblying it outside was to fit check the cowling. This went very well and I'm pleased with the results.

Next step is to install the fuel injection system, and the ducts in the lower cowl for oil cooler and induction air.

16 JUNE 2007 Wings / Cowl Attach

Although difficult to see, this is the back of the top cowl. A lip/flange is being made. The bottom cowl will attach to this lip.

The lip is made of 5 layers of BID that is laid up inside the the cowl.

Oil check door;

Duct tape is installed on the inside of the oil door. The door is then held in place with a piece of wood that has been bondo into place. This will hold the door secure while the layups are performed inside

Four layers of BID are layed in place. These will be cut off after cure to form a 1/4 inch lip all the way around.

After cure, the door was popped off and a hinge is installed.

11 JUNE 2007 Wings / Cowl Attach

Two layers form the lip from the top to the bottom cowl. When this cures, additional layers of BID will be layed up inside, along with a small amount of flox.

Note the small twisted safety wire. This is holding the two halves of the cowl together at the correct angles.

9 JUNE 2007 Wings / Cowl Attach / Temperature Testing

The top cowl attach points to the wings are now aligned and fit check OK. Because of the differences in the old cowl and the new cowl, the cowl tab on the wing is not at the correct angle. To correct for this, I added FLOX filler to the new cowl were it bolts to the wing. I still need to put one layer of BID over this to secure it.

The back junction, where the top and bottom cowls meet. This is now cleaned up. I still need to make the tab for this.

WING SURFACE TEMPERATURE

There has been much discussion regarding exterior color. Rutan recommend white, as this absorbs the least amount heat.

Skin temperature is particularly important where Blue Styrofoam is used in the wings and canard. The blue foam starts to deteriorate at approximately 160 Deg F. When the foam deteriorates, it delaminates from the fiberglass skin which degrades the structural integrity of the wing.

READ THIS FIRST, TEMPERATURES

There are a couple abnormalities in the data that I'm not able to explain. Therefore, I'm not going to take this as final until I can come up with explanations. If you have any ideas, please send me an e-mail:

waiter AT iflyez DOT com

Skin temperatures were read using a RayTek hand held non contact thermometer (laser gun). Air temperature (OAT) was read using a calibrated RTD Electronic thermometer. Sun angle was measured using a homemade Sextant.

RH - Hot side of rudder, find the hottest point on the sun side of the rudder

RC - Cold side of rudder, find the hottest point on the shaded side of the rudder.

GRAY - Wing, gray paint. find the hottest point on the gray area.

LT Gray - Wing, LT Gray paint. find the hottest point on the Lt Gray area of the wing

SUNDAY	10 JUNE	2007	KTDZ	AIRPORT
TIME	OAT	SUN	RH	RC	GRAY	LT GRAY
		ANGLE
9:45	71	42	97	76	122	103
10:45	72	53	110	83	139	114
11:45	74	64	110	88	137	111
13:00	75	72	111	90	137	112
14:00	76	73	104	90	139	112
22:00	62	ZERO	59	58	48	46

TEMPERATURE READING OBSERVATIONS

1) Although the surface temperature read 137 deg F, I was able to hold my hand on the surface. It was hot, I would guess 120, but I would not have guessed 137??

2) The Wing gray areas read about 15 deg F hotter than the gray areas on the strake. The unscientific "hand" test seemed to indicate they were both at the same temperature.

3) The night time temperature test on the wing was about 15 degrees below what it should have been, i.e. it was readiing 48 Deg F when the OAT was about 62 Def F.???

ANYBODY GOT ANY IDEAS ???

UPDATE - UPDATE - UPDATE - UPDATE - UPDATE - UPDATE - UPDATE - UPDATE

Marc Z from the Cozy Builders (smart guy, he's forgotten more about airplanes than I learned my entire life!) sent me a good explanation on the three questions from above. This is my interpretation of what he said!

1) The thermal mass of the two layers of fiberglass is very small. So, even thought its hot, as soon as something touches it, it cools down a little. When I put my hand on the surface, my hand absorbs the surface heat and temporarily cools it down. The RayTec None-Contact laser temperature gauge doesn't touch the surface, so it doesn't cool it down.

TEST THIS THEORY - Take a temperature reading, then place your hand on the GRAY surface for a couple seconds. Remove your hand and immediately measure the surface temperature with the RayTec. It should be significantly lower.

CONFIRMED - Using the RayTec, I found the hottest spot on the gray area that was 138 Deg F. I placed my hand on this area for about 5 seconds. When I removed my hand the temperature read 120 Deg F.

2) The blue foam under the wing area is not a good conductor of heat. The foam under the strake area conducts heat much better. Therefore, the skin temperature over the blue foam will be hotter, because the blue foam isn't absorbing heat from the skin as well as the strake foam.

3) The top of the wing is "radiating" heat faster than its able to absorb heat from the atmosphere (clear sky, there is nothing above the wing that's radiating heat). The rudders are radiating also, however, they are also absorbing heat from other sources, pole barn, trees, cars, houses, etc.

TEST THIS THEORY - Measure the temperature of the bottom of the wing with the RayTec. If radiation is the reason for the difference, than the bottom of the wing should be approximately the same as the rudders. The ground (dirt, grass, etc) is also radiating heat, this heat will be absorbed by the bottom surface of the wing. There is nothing above the wing radiating heat, so the top surface of the wing should be colder.



CONFIRMED - The temperature differential on the wing, particularly, "How can the skin temperature be lower than the outside air temperature?" is a result of heat radiation.

The bottom of the wing is absorbing more heat energy (from the ground) than its radiating.

The top of the wing is radiating more energy than it absorbing (from the air above it), so its much cooler.

THE TEST - I went out about 10:30 pm (1 hour after sundown) to take some measurements with the RayTec.

When pointed straight up into a clear sky, the gauge reads 1 Deg F. As I slowly moved the RayTec down to the horizon, the temp increased to 64 Deg F. The outside Air temperature read with a regular thermometer read 68 Degrees.

The readings on the plane were similiar to those I took a couple nights ago.
     68 = OAT (measured with thermometer)
     51 = TOP OF WING
     65 = BOTTOM OF WING
     63 = RUDDERS (both sides)
     65 = Grass/Dirt

There's a good writeup on RayTec's web site that explains how these none-contact devices work.

Don't you just love this science stuff. :-)

9 JUNE 2007 Wings / Cowl Attach

Mounted the wings. Needed to sand off about 1/8 inch of the wing lip to clear the strake (where the new end cap bulkhead is installed on the end of the centerspar)

The cowlings need to be trimmed to fit against the wings and the fuselage.

Mounting hardware is now installed on the cowl lips.

The lower cowl mount to the wing is OK (after trimming), but the top of the wing (the lip the cowl mounts to) will need to be modified.

Also, the rear of the cowls were the top and bottom meet needs to be worked on.

All in all, the plane looks very good. The cowls are clean and should reduce the drag compared to the original cowls.

6 JUNE 2007 Cowl Attach points

Cleaned up the cowl lip and removed the peel ply on the top and bottom cowls. Initial fit check looks very good.

Made a template for the oil door out of paper, then positioned the templated over the upper cowl to provide optimum access to the filler tube. Marked and cut the oil door in the top cowl.

3 JUNE 2007 Cowl Attach points

Two layers of BID on the outside, and three layers on the inside, both upper and lower cowl.

2 JUNE 2007 Cowl Attach points

A small mound of flox is placed on the temporary tabs. The cowling is then placed in position on the tabs and held in place by wood screws.

After the flox cures, the cowling is unscrewed, and the wooden forms are removed. What remains is the BID tabs now floxed to the cowl. The tabs and flox will be cleaned up, the two layers of BID will go on the outsd and three layers on the inside to form the cowl mounting tabs.

1 JUNE 2007 Cowl Attach points

This is two layers of BID with peel ply on both sides. The cured BID is cut into 2 inch strips.

The fuselage cowl lips are taped off so that flox will not stick to it. The BID strips are then secured to the inside of the fuselage cowl lips using pieces of wood. The wood holds the strips up tight against the fuslage cowl lips.

The cowl is then fit checked and the forward edges are cut/sanded so they line up with the fuselage.

The top cowl is ready for flox. I'll run a bead of flox on the BID strips so they stick to the inside of the cowl. After cure, I'll remove the screws that are holding the wood and strips to the fuselage. Then two layers of BID on the outside of the new "cowl Tabs" and three layers of BID on the inside. These will form the forward mounting tabs for the cowl.

I'll prep the bottom cowl this weekend, basically the same way.

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