FLIGHT!!!!

Preparing for first flight on 18 Dec 99. Flight suit, Nomex gloves and hood, and (sigh) a bicycle helmet. The bicycle helmet provided a degree of protection, while allowing me to use "ear bud" earphones plugged in to the Flightcom intercom's aux-out port. Worked great.

First flight of my new RV-6A was scheduled for 10AM on 18 Dec 99. My ground support team (two fellow officers from the Pentagon, both pilots) and the Manassas volunteer Emergency Medical Services crew were on hand, as were my wife and 20-month-old son. Out of the woodwork appeared another 10 or so folks, so there was quite a crowd. I put on my Nomex gloves and hood, and strapped on my stupid looking bicycle helmet (safety first). The engine started right up... and was soon making horrible "POP" noises every few seconds. The EIS engine monitor showed number 4 CHT was barely above room temperature, while the other CHTs were rising up to 200 degrees. Number 4 EGT is 300 degrees, while all the others are well above 1000 degrees. Nuts. Shut down the engine. The ground support team confirmed loud "pop" noises coming from the engine.

We pulled the cowl and confirmed number 4 was cold, while the other cylinders were hot. We cleaned the plugs. No good. We swapped plugs. No good. The crowd starts to disburse. I sent EMS home. We verify both the mag and the electronic ignition are producing sparks at their respective spark plugs on cylinder 4.

Frantic phone call to Chapter 186 Tech Counselor Dick Koehler (A&P, IA, A/C MX instructor, retired USN pilot, etc etc) gives some good ideas to start diagnostics. Compression check reveals number 4 has good compression, so the exhaust valve isn't stuck open. We pull the valve cover and note that both the intake and the exhaust valves work just fine, and number 4's combustion cycle is right before number 1's combustion cycle, so there's not some horrible problem with the cam. In hopes that there's some valve sticking due to different coefficients of expansion on the new engine, we heat the cylinder up with a propane engine heater (Red Dragon) and try it again. The problem is still there.

Yet another call to Dick, and we start ticking off the physics basics. Dick calls this "an easter egg hunt." Do we have spark? Yes. Do we have rotation? Yes. Do we have compression? Yes. Do we have the proper mixture? Don't know. Maybe something got in the carb and jammed up inside the intake to number 4. Maybe the hose from the carburetor to number 4's intake split or something... VOILA, I know what it is!!! It has to be something to do with the Standby Vacuum System that takes it's vacuum from number 4's intake. Run back outside. Yell to the ground team "I know, I know, it's that &^%$ standby vacuum system."

The Precise Flight Standby Vacuum System (SVS) uses the low pressure from an intake manifold (#4 on my plane) to provide an emergency backup source of vacuum to run the artificial horizon and directional gyro in case of vacuum pump failure during IFR flight. The SVS is installed by drilling a 3/8" hole in the hose that connects #4's intake pipe to the carburetor. On to that 3/8" hole is clamped a flat plate with a tube connector which leads to the SVS system on the firewall.

On my installation I think I had used insufficient RTV between the plate and the intake hose, leading to potential leaks. In addition, the SVS system has one clamp the flat SVS plate on to the curved intake hose. This distorts the hose, leading to the potential for leakage through the distortion.

I used fluting pliers to impart a curve to the flat SVS plate, applied lot= s of RTV between the SVS plate and the hose, and applied RTV to the remaining distortion areas in the intake hose.

Cross finger, start engine, watch the CHT and EGT on number 4 soar along with the other cylinders. Problem solved!

Ready for first flight! Most of my pre-flight jitters have been consumed by the effort to fix the engine. Manassas lets me do high speed taxi tests on taxiway Alpha, then I get to sit idling for 20 minutes waiting for departure clearance from Manassas tower. CHTs are around 350 degrees. This is not what my new engine needs, but I don't have much choice if I want to fly today. I call tower and tell her that I'm STILL number one at Kilo. Ooops, she says, she'll get me cleared right away.

"N47TD, cleared for immediate departure, traffic turning base to final." Yahoo! Full throttle, watch the airspeed come up, nose up, and I'm flying! The stall horn is blaring away, but I ignore it because my climb attitude is right, controls feel right, and I'm accelerating and climbing. I climb out at a climb cruise speed, because Vx feels way to steep for first flight. The engine monitor light starts flashing, and my heart jumps into my throat. What is it? Oh, RPM has climbed to 2710 (limit is 2700). Pull the prop back to 2600 rpm and keep climbing with full throttle to take advantage of the extra cooling from the rich mixture at full throttle (see Dick Koehler's recent Stick and Rudder article). 2000'arrives in no time, and I have to level out so I don't bust Dulles' class B airspace.

Another red flashing light. What is it now? One of the CHTs is above 430 degrees (that's my warning limit, although Lycoming calls redline 500 degrees). OK, let's think about this. The cylinders got good and toasty on the ground, and this is a brand new engine, so high CHTs aren't unusual at the beginning. I've been running high power per the Lycoming break-in instruction. OK, let's pull the power back and see if it'll cool down. Level flight departing the pattern, CHT starts to drop one degree every few seconds. At 430 degrees the flashing light goes off. Relax, time to head to Warrenton and do some stalls.

First, however, it'd be a good idea not to fly into the restricted area that my Garmin 195 says is about 1 mile in front of me. (Let's see now, what were my priorities supposed to be? Aviate; fiddle with engine; navigate?).

Climb to 7000' enroute to Warrenton, CHTs are just fine. Slow to 90 knots. Stupid stall horn is on all the time. Pull the breaker, make a note to adjust the thing later. (Here=92s yet another example of the utility of standard, accessible breakers). Slowly decelerate, bring the nose up, wait for the burble. Wow, indicated airspeed is under 40 when it finally starts to shudder. (My pitot/static tube has static ports on the top and bottom of the pitot tube, so it's likely my airspeed error is significant at high angles of attack -- actual stall speed is probably around 50 knots.) Lower the nose, try it again. No surprises, no wing drop. The test plan says no full stalls on first flight. Try deploying flaps. They won=92t move. Ahh, they=92re on the same circuit as the stall horn. I don=92t want to listen to that thing, s= o let=92s just forget about flaps on this flight. Next, practice flying the pattern at 3000-4000'. No surprises there.

I head back to Manassas, being sure to get down under the class B, and call Manassas 10 miles out. The tower calls my traffic on base to final, tells me I'm number 2, and tells the next guy that he's number 3 behind "the fast mover experimental." Now that's funny! My little 2- seater that's spent the last 3 1/2 years going zero mph in the garage is now a "fast mover."

Approach is at 78 kts like Van's factory instructor, Mike Seager, taught me for first flights (70 knots after more experience and flight tests).

Over the numbers, flare, keep the nose up, keep the nose up, on the brakes while the nose is still in the air, lower the nose, and I turn off the runway at the first turn off! What a great feeling!

In order of importance:
1. I'm not dead!
2. It flew great!

Stats:
- Aircraft: RV-6A Serial Number #60023
- Engine: O-360 A1A with Hartzel C/S prop
- Ignition: Lightspeed Electronic Ignition plus 1 mag
- Engine Monitor: EIS 4000 (all 4 CHT and all 4 ETG simultaneously, plus RPM, MP, Oil Temp and Pressure, fuel pressure, OAT, bus voltage, and more --great system)
- IFR panel
- Navaid autopilot
- Garmin 195 panelm mounted, wired to Navaid
- D.J. Lauritson interior
- Paint: Imron over Corlar, done by yours truly (first time painter)
- Electrical Power: 60 Amp automotive alternator modified for external regulator (see my web page, http://home.earthlink.net/~timrv6a for instructions)
- Weight: 1162 lbs
- Constructed in about 2000 hrs over 3.5 years

I'd recently completed a BFR in a Cessna 172 after 3 years of not flying. Then I spent 2.8 hours with Mike Seager (factory instructor pilot, near Portland Oregon), who pronounced me fit to do an RV first flight.

Thanks to:
-My wife Debbie for putting up with this project for the last 3.5 years (and loaning me the $$$ for the engine)
-EAA tech counselors Brian Tobias (EAA Chapter 35, San Antonio), Dick Koehler (EAA Chapter 186, Virginia) and Chuck Shedd (Chapter 186)
-Jim Cone for great canopy instructions
-Van and crew for a sweet flying airplane
-Mike Seager for quality flight instruction in the factory RV-6A
-Matt Dralle's RV-list, including GV, Mark Frederick, Mark LaBoyteaux, and the gang
-Lt Col Ralph Strother: riveting, bucking, test, ground support

Tim Lewis
N47TD FLYING!!!!!