I have been very curious about actual best range performance of my RV-6. Ever since last fall when on an IFR cross country when poor weather made me begin to contemplate “If I can’t get into here because of extreme low weather, how far could I go to get to better conditions and where would I have to operate (power settings vs performance) to get there“???
I have read all the posts about LOP and best range and min glide and L/D max and Whozit’s speed. But no where in there did I find any definitive data. So I decided to let my airplane tell me.
Today was smooth with light winds. I devised a flight plan to fly multiple race track patterns above a known landmark and use the GPS and fuel flow equipped EIS4000 to turn the plane into a calculator. I chose a distant direct to waypoint - TPK, 735 miles distance. Each pattern I crossed the same point, on the same heading, same 8000’ altitude, GPS tracking direct to TPK. On the “downwind leg” of each race track, I adjusted power to a new setting and stabilized the engine. Then turned onto the track. As I crossed the 735 mile away point, I reset the fuel onboard to 38 gallons. Then I recorded all of the data. They are spread sheeted below.
Best Range 3/26/10 N1024R KVVS to KTPA 735 mi 8000' 32F oat
RV-6 IO-360 RV200 Prop 1 Mag/1 LSE Plasma 2 ES4000 with fuel flow
Run 1 - WOT, 125 ROP, slightly less than my normal 2400/WOT best power x-cnty cruise
Run 2 - WOT, 25 LOP
Run 3 - WOT, 25 LOP 1900 RPM, CHT 285, 145 oil temp with my oil cooler door closed
Run 5- CHT 250 LOP for smooth running Run 6 - CHT 230, LOP for smooth running
Run 7 - Oil temps rising, 171 with door cracked, CHT’s rising 275
Run 8 - Things getting unstable - hard to hold A/S, Can’t recover altitude, performance totally dependent on fuel flow - ain’t gonna happen in real life
Wow I learned a lot. First of all, I could make it TPK from KVVS (east of Pittsburgh) non stop if I wanted to!!! My LOP operations have always shown an unsettling EGT rise at about 50 LOP as engine roughens. This was uncomfortable and still is. As percent power goes down, peak becomes less distinct and just setting up for smooth running LOP is easiest. As airspeed and power goes down, performance can be controlled by fuel flow. Much below 12.5 inches and LOP, things just get squirrelly all around. Temps begin to rise (reduced airflow probably), prop is about on the min stops - it is just all squirrelly.
What did I learn about efficient cruise and max emergency range?? - Just going LOP is a quantum leap in efficient cruise (I think we all knew that). If I was in a real pinch, 20”/1900 LOP looks like great place to be while 16.7“/1900 could really stretch it in an emergency (lost over the north atlantic).
These are some incredible airplanes. Now maybe I understand the -9 better.
I welcome anaysis by the aero and graph/math guys. Very interesting and finally some numbers with confidence for the POH.
Still having trouble tabulating the data - first colum is ETE, second is endurance, third is minutes in reserve, the fourth is map/rpm, the fifth is max EGt/set EGT, sixth is IAS, seventh is GS, 8th is fuel flow, last is total fuel used to get there. Hope it helps someone else. Thanks
I have read all the posts about LOP and best range and min glide and L/D max and Whozit’s speed. But no where in there did I find any definitive data. So I decided to let my airplane tell me.
Today was smooth with light winds. I devised a flight plan to fly multiple race track patterns above a known landmark and use the GPS and fuel flow equipped EIS4000 to turn the plane into a calculator. I chose a distant direct to waypoint - TPK, 735 miles distance. Each pattern I crossed the same point, on the same heading, same 8000’ altitude, GPS tracking direct to TPK. On the “downwind leg” of each race track, I adjusted power to a new setting and stabilized the engine. Then turned onto the track. As I crossed the 735 mile away point, I reset the fuel onboard to 38 gallons. Then I recorded all of the data. They are spread sheeted below.
Best Range 3/26/10 N1024R KVVS to KTPA 735 mi 8000' 32F oat
RV-6 IO-360 RV200 Prop 1 Mag/1 LSE Plasma 2 ES4000 with fuel flow
reserve max set tot fuel
ETE Range mins Map/RPM EGT/EGT KIAS GS FF Used
4:32 3:39 -44 23.4/2200 1500/1350 165 163 10.5 46.1
4:57 5:12 15 23.4/2200 1485/1460 150 149 7.3 36.14
5:11 5:45 34 23.2/1900 1425/1400 143 142 6.6 34.21
5:21 6:19 58 22/1900 1440/1410 139 137 5.9 31.5
6:48 8:05 77 19.7/1900 1440 110 108 4.7 31.0
6:48 8:50 132 16.7/1900 1400 110 109 4.3 29.24
7:41 10:44 183 96 93 1405 96 93 3.7 28.42
11-12/1900 1400
Notes: ETE Range mins Map/RPM EGT/EGT KIAS GS FF Used
4:32 3:39 -44 23.4/2200 1500/1350 165 163 10.5 46.1
4:57 5:12 15 23.4/2200 1485/1460 150 149 7.3 36.14
5:11 5:45 34 23.2/1900 1425/1400 143 142 6.6 34.21
5:21 6:19 58 22/1900 1440/1410 139 137 5.9 31.5
6:48 8:05 77 19.7/1900 1440 110 108 4.7 31.0
6:48 8:50 132 16.7/1900 1400 110 109 4.3 29.24
7:41 10:44 183 96 93 1405 96 93 3.7 28.42
11-12/1900 1400
Run 1 - WOT, 125 ROP, slightly less than my normal 2400/WOT best power x-cnty cruise
Run 2 - WOT, 25 LOP
Run 3 - WOT, 25 LOP 1900 RPM, CHT 285, 145 oil temp with my oil cooler door closed
Run 5- CHT 250 LOP for smooth running Run 6 - CHT 230, LOP for smooth running
Run 7 - Oil temps rising, 171 with door cracked, CHT’s rising 275
Run 8 - Things getting unstable - hard to hold A/S, Can’t recover altitude, performance totally dependent on fuel flow - ain’t gonna happen in real life
Wow I learned a lot. First of all, I could make it TPK from KVVS (east of Pittsburgh) non stop if I wanted to!!! My LOP operations have always shown an unsettling EGT rise at about 50 LOP as engine roughens. This was uncomfortable and still is. As percent power goes down, peak becomes less distinct and just setting up for smooth running LOP is easiest. As airspeed and power goes down, performance can be controlled by fuel flow. Much below 12.5 inches and LOP, things just get squirrelly all around. Temps begin to rise (reduced airflow probably), prop is about on the min stops - it is just all squirrelly.
What did I learn about efficient cruise and max emergency range?? - Just going LOP is a quantum leap in efficient cruise (I think we all knew that). If I was in a real pinch, 20”/1900 LOP looks like great place to be while 16.7“/1900 could really stretch it in an emergency (lost over the north atlantic).
These are some incredible airplanes. Now maybe I understand the -9 better.
I welcome anaysis by the aero and graph/math guys. Very interesting and finally some numbers with confidence for the POH.
Still having trouble tabulating the data - first colum is ETE, second is endurance, third is minutes in reserve, the fourth is map/rpm, the fifth is max EGt/set EGT, sixth is IAS, seventh is GS, 8th is fuel flow, last is total fuel used to get there. Hope it helps someone else. Thanks
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