Sloooooow flight.

This morning a friend flying an Ercoupe and me in my RV9A flew to a fly in breakfast. I wanted to stay close so I throttled back to just under 1800 RPM and 92 kts. to match his speed. I was burning 4.2 gallons per hour. It was a short flight of about 25 minutes. Is there any problem in running the engine at a speed that slow for short periods? My engine is an E3D 150 HP with fixed pitch prop. All the temps were in the green and the engine seemed smooth as silk.

There should be no problem doing that as long as your temps are good and you are not in the breakin period. Did you lean at all? I would expect fuel flow a little lower Han that. They do fly slow. I flew formation (not tight) in an RV-10 with a Zenith 701 Amohib for about 45 minutes. I was hanging about 10-15 knots above a stall with a notch of flaps.

I have a 9A with the same engine and I frequently fly with a couple of zenairs and a rans. With them max cruise is at most 105 - 110 mph. I throttle back to about 1700 rpm. I don't have fuel flow but I think I'm about 4 - 4.2 gph. The nine handles fine at that speed. My only concern is that the oil temp only gets to about 150. I lean aggressively at that low power setting. A lot of times on the way back I have to tell em, "guys I have to throttle up to get my oil temp up for a while" and head out. I'm running with the oil cooler half covered, which seems about right for summer. At 2350rpm and 90 OAT the oil temp is about 185deg. In winter I block it completely. Funny thing is the Zenairs are running a very high power setting and burning about 6.5 gph. These RVs truly are amazing!

You must be flying with 601/650's. The yellow arc starts at about 75mph in the 701. I agree, amazing birds.

want to share some data?

I would love to know your calibrated airspeed at minimum power for level flight and your weight at that point.

CAS is IAS plus or minus error. You can get there backwards with GPS giving you TAS (fly upwind/downwind & average or fly the triangle and use the NTPS spreadsheet) then correct with altitude and temp to get CAS.

I always lean, even on the ground. I was running 50 deg. ROP. I am carbed. I just finished my condition inspection and all the plugs were a light tan color and no lead deposits at all on the top plugs and only very slight leading on the bottom with no clinkers in the bottom of the plugs. I was holding 1760 Rpm and 90 kts. Indicated and he was very slowly pulling away. At 1800 RPM I was very slowly overtaking him at 92 Kts. Indicated. The fuel flow was bouncing between 4.2 and 4.3 gal.

I just participated in a celebration flypast for my local airport (CYNJ, Langley, BC), for its 75th year in operation. We hoped to have 75 planes fly in a line-astern loop around the airport and city, but in the end could only muster 57. I told them dyslexia fixes everything!

We had everything from Cessna 150's to a Seneca Twin (local flying school) and three RV's, so the speed was set at 100mph. I flew at 1750 rpm, two notches of flap (20 deg) and had no problems at all. EGT's just under 1300, CHT's between 300-350. Fuel burn was 15-16 litres/hr (about 4 gal/hr), a little over half of my usual fuel burn in cruise.

The Seneca pilot said that he didn't know what was making the most noise... The gear warning, stall warning, or the co-pilot pointing out the two other warnings...

Sloooooow flight....... in my 6A is 65 knots and under. So in your 9A, allow the airplane to show you what it can do.

At 92 knots you are in a very safe and stable flight profile. I don't think it would be called slow flight during a BFR.

Fly at 65 knots, and make some turns and you will be just as comfortable in a very few minutes. Watch your temps.

Are you going to Oshkosh Jim?

If you are the start point for the AirVenture Cup Race is nearby this year for the first time. Mt. Vernon, Illinois. Today is the last day for registration but they will take almost any action of intent to race as a place holder and alow you to complete the details later. That would allow you to clear out the cobwebs and show your buddy what you can do. As a matter of fact they have a class for him too at two legal no time penalty fuel stops along the route. I talked to Jim Younkin about him flying his Mr. Mulligan but he said that was a young man's activity. www.airventurecuprace.com

Bob Axsom

A week ago I was visiting Piper Cub gathering at Lock Haven PA with Turbo, cousin and Jim Lewellyn. I "inserted" myself between Cubs and flew their pattern at 60-65 kts and landed at "their" 27L runway. It was very fun and uneventful. The only thing non Cub-like was I used ALL the runway. Two times I added power to jump over a soft spot. Stopped at the end my guess is Cubbers had a good laugh




On our recent visit to Stanley, NS I flew 55 kts in ground effect over all their three runways (triangled) in one closed circle. RV9 has a very unique wing which adds to the fun. As soon as Paul Tuttle learned that his runways are in great shape he soloed his RV8

I fly formation weekly with a group of slow airplanes: Glastar, Great Lake, Dova light sport, Cessna 140, Piper Pacer, Jabiru, Stinson, Maule, Decathlon, Cherokee, etc. 90-100 kts is the norm. In an inside turn I had to pull power to almost idle. So far I never have any issue with the engine and the control. I always lean when taxi. In the air when I reduce power to join the formation I lean. Of course I don't get a chance to see how much I leaned. At each oil change my plugs look good.

Thanks for all the good input.
I was only referring to cruising at a slow speed, not control issues.
Sorry Bob but not ready to enter races. I probably won't attend OSH this year.

49clipper

My record so far is 90mph @ 3.2 gph in my RV-6 with an O-320-D1A. did this several times, leaned of course. I never fly without leaning except TO and climb.
Jim
RV-6