hans
Full Member
Posts: 166
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Post by hans on Sept 29, 2011 15:43:16 GMT -5
Hi Group,
today I finally took my S-II up for my first flight. At 3000' (due to temp the density alt was a bit higher) I got an IAS of 130 KTS / just shy of 150 MPH @ 3450 RPM WOT (2180cc, 54x48 Sterba). Do these numbers check with your experiences, or is this the start of a quest to find more speed ? ;D
cheers Hans ____ Sonerai-II PH-ERA
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Post by martinroy6100 on Sept 29, 2011 18:02:20 GMT -5
Hans: OK so do you have wheel pants? You say this is your first flight I would say give it some hours to get broken in. Next did you check this against a GPS, as your airspeed indicator could be off. Your RPM seems a little low, how do you know that is the correct reading?. I get in the 145Kts at that RPM and altitude and I have what Ed sais is a 54x48, but they are all somewhat different. I would not pay too much attention to these numbers until you have some time and you may find small treeks that will improve that number.
Martin Roy N61QC
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Post by schrome on Sept 29, 2011 18:30:40 GMT -5
Congratulations, Hans!
When I checked WOT performance last autumn I saw 150 mph / 3530 rpm at 2500 ft. Air temp. at that altitude was 54 F. Yes, it sounds like you're getting the fever.
Ed 2LS with GP 2180 and Sterba 54x48
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Post by daddo2 on Sept 30, 2011 13:04:30 GMT -5
Congrats Hans! Those numbers are identical to mine turning a 54x46 Sterba.
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Post by martinroy6100 on Oct 3, 2011 9:18:10 GMT -5
Hans: OK so I lied, I guess.
Friday I took her up to 4300 feet with a 62 degree day and got 130K at 3450 sounds familiar does it not? the 145K was at sea level at on a 50 degree day.I have a 2276 with a 54x48.
Martin Roy N61QC
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hans
Full Member
Posts: 166
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Post by hans on Oct 3, 2011 9:57:18 GMT -5
Thanks for your feedback. So my figures are about in the ball park. Checking the validity of my measuring instruments & methods is a valid comment though, which is what I'm going to do the next time I'm up out there.
One more data point, 'cruise configuration' this time:
Last week Friday I took my S-II up on a 55 NM / 63 miles sortie to the south and then straight back home. Surface wind was calm @ 170°. The entire flight I cruised at 3000 RPM @ 2000' MSL. Ambient temp at ground level was about 8°C above ISA, a mild inversion might/will have caused a somewhat larger delta from ISA at 2000' (I don't have an OAT yet). Flying south the GPS told me I did 97 kts over ground, on the way back it read around 117 kts, which would average into appr. 107 kts / 123 mph. Not quite what I expected when I purchased my bird last June...
So apparently the quest is on...
Jürgen already suggested I clip my prop blades a bit to free up the engine, RPM/power-wise. I prefer to work on the airframe first, as then perhaps I won't need a shortened prop...
Hans
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Post by martinroy6100 on Oct 3, 2011 11:17:48 GMT -5
Hans: Now that I lied to you once I have to be more careful and think before I answer. Generally I fly at or around 3000 feet and here in Washington state, the temps are usually at or close to standard. I fly at 3100 and get about 122K indicated. The GPS usually tells me I am flying 5K faster. My usual GPS distance flown to hobbs time speed falls in the 110K for trips in the vicinity of one hour with a fuel burn of 4GPH. On Friday I flew 2.3 hobbs at 4300 feet with one stop, power was set at 3200 and I averaged 120K for the trip with a fuel burn of 4.4GPH. Others have larger tanks and if you could fly say 2.5 hours per trip with only one climb and taxi i know that the average speed would be closer to 120K at 3100. Last month i few to Republic fly in, the trip was 600K I climbed a cumulative elevation of 23000 feet and landed five times. My fuel burn at 3050 at 6500 feet was 3.9 GPH. There are real numbers, try to see what the numbers would be for a C150 we are sooo much faster and cheaper.
Martin Roy N61QC
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hans
Full Member
Posts: 166
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Post by hans on Oct 3, 2011 13:18:45 GMT -5
Hi Martin,
thanks for these detailed data points. These and other discussions made it clear to me that I need to establish a base line before altering anything and to be able to do that I need to improve my current instrumentation. And as to fuel qty: I really need to get more than the current 10 gallons, to get a bit more utility from my S-II.
cheers Hans
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Post by martinroy6100 on Oct 3, 2011 15:02:48 GMT -5
Hans: I tend to be reluctant to fly much more than 1.75 hours per hop as the fuel level indicator becomes unreadable below 8 gallons and after that much time my legs need to move. The Republic Fly-In just happen to be located so the worst possible fuel scenario occurred for planning purposes. I could of stopped once less but I had high temps east of the cascades and fog west of them. This forced me down once to wait for the weather. I am contemplating an extra tank but for the type of flying I seem to be doing it does not apprear to be necessary. Fly it for a season before you attempt any major modification. Are you in Germany? or the states.
Martin Roy N61QC
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hans
Full Member
Posts: 166
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Post by hans on Oct 3, 2011 15:38:51 GMT -5
Martin, I'm based in the north of Germany. My S-II is based on EDXR. With a 10 Gal. tank I started to feel uneasy as soon as the level dropped below 5, which was a bit over one hour. For my type of flying, I'd need (or like to have) a range of around 2.5+ hours and still have a safe reserve. 10 Gals. don't fit that bill, so I'm going to add to that. You're right though, I need to get acquanted with my bird before I butcher her up... Also more accurate data like that provided by a fuel flow indicator could possibly put my concerns at ease... cheers Hans
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Post by daddo2 on Oct 3, 2011 20:37:05 GMT -5
Hi Martin, Just finished a 1150nm trip in my Cessna 150. So to answer your question a 600nm trip in a C-150 at an average 95kts cruise, allowing for taxi, run-ups,and climb, would take about 44gals and 6.5 hrs (no wind). Roughly twice the fuel and 1.75 hrs more than a Sonerai.....FredL. ps... flew the return trip in a newly aquired Bellanca Viking. 1150 nm in 7.3 hrs and in case you're wondering.....106gals. When it comes to efficiency Sonerai's are hard to beat.
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peterzabriskie
Junior Member
"Did I make that part the best I possibly could have?" Unknown
Posts: 99
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Post by peterzabriskie on Oct 20, 2011 13:42:49 GMT -5
Just Curious here because the type of "visit the local fly-in" flying is what I plan to do. Is the Turtledeck Aux Tank GPASC offers and what I see in Pttim's photos a difficult add on? :)Pete
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hans
Full Member
Posts: 166
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Post by hans on Oct 21, 2011 4:22:55 GMT -5
Just Curious here because the type of "visit the local fly-in" flying is what I plan to do. Is the Turtledeck Aux Tank GPASC offers and what I see in Pttim's photos a difficult add on? :)Pete Last SpringI did a pre-purchase inspection of a French registered Sonerai IIL, which sported a 6 gal. turtle deck aux tank. It didn't look all that complicated. The owner commented that as his setup gravity feeds into the main tank, you need to make a point of NOT having that aux tank valve opened during take-off and landing. His setup allowed fuel to syphon BACK into the aux tank when not in a horizontal pitch attitude, possibly emptying the main tank in the process.... Just something to keep in mind should you go the gravity feed route... And no: I didn't purchase that French job - I didn't like at all what I saw there... Hans
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pttim
New Member
Posts: 30
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Post by pttim on Oct 21, 2011 11:35:36 GMT -5
It was not difficult to mount the turtle deck tank, mine has an electric fuel pump underneath and will be used to fill the main tank.
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Post by martinroy6100 on Oct 21, 2011 13:34:43 GMT -5
Hans: My plan is to add this winter the necessary plumbing to have a tank on the passenger floor. I have chosen to use the turtle deck for a luggage compartment and to place the auxiliary tank on the floor. The tank will be connected using outboard motor to fuel tank connections and anty siphon check valves with a pump. I have all the parts and we will see how it all works. The connections chosen will allow the tank to be removed quickly.
Martin Roy N61QC
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