True, true airspeed on a C-180?

DKirkpatrick

DKirkpatrick

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DKirkpatrick
Hello. I know there's a ton of variables like how good of a pilot you may be... but what is a real TAS for a Cessna 180, with an O-470R? And I know the airplane's designed to be a hauler, etc., but want to just know a good planning speed for a three hour flight, 7000' average?
thanks for the coaching in advance.
dan
 
There probably is a chart in the paper wheel chock behind the seat, but I’d say it probably cruises 130-140 KTAS and burns 13-14 GPH.
 
DKirkpatrick said:
Hello. I know there's a ton of variables like how good of a pilot you may be... but what is a real TAS for a Cessna 180, with an O-470R? And I know the airplane's designed to be a hauler, etc., but want to just know a good planning speed for a three hour flight, 7000' average?
thanks for the coaching in advance.
dan
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Depends on tires and mods. My stock 180 with O470R on 8.00's cruises at 135KTAS and burns 12GPH
 
I run 18", 2300 rpm I get about 143MPH true from 8000' and up'. But, I have 29" bushwheels. With 8.50's I was doing 153mph at the same settings. Burning 10.8 to 11.2 gph. I run it lean at those power settings.
 
I fly low. 140-145 mph with 29” mains and BBW tailwheel. On 800s and an 8” tailwheel I saw 185mph at 1000’ MSL. I have a Pponk and 86” 3-blade. It’s been too long since I had a 470. No memory.
 
Thans for the replies. I appreciate the help
 
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Sinistar said:
Hard to imagine its much over 150mph / 130kts.
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Why are you trying to (incorrectly) imagine, when several people in the thread *with* the exact airplane being asked about have answered?
 
I fly a stock O470 182. It has that little nose wheel thingy and often you guys have those big main gear thingies. Airframes and weights aren't all that different. Ours, rigged pretty nice now, does a bit over 150MPH true. But the OP is free to disregard my answer. If it really bugs you that much I can remove my answer just let me know.
 
Sinistar said:
I fly a stock O470 182. It has that little nose wheel thingy and often you guys have those big main gear thingies. Airframes and weights aren't all that different. Ours, rigged pretty nice now, does a bit over 150MPH true. But the OP is free to disregard my answer. If it really bugs you that much I can remove my answer just let me know.
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Depending on year, the 182 has a wider cabin, isn't fast back, and has a big nosewheel in the high pressure area adjacent to the prop. Just striving for accuracy, not guesses.
 
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I’ve had my 180 for 26 years. Speed was never a priority but when I fly my Cub it sure makes me appreciate it. My Cessna experience is that aft CG promotes faster cruise. And for landing or taking off short a central CG is better. IMG_0022.jpeg
 
Here’s a couple of my numbers for a O520 180 with 850’s and a Horton.

2.5’ 19” 2200 10gal 130 true
10.5’ 19” 2200 11gal 144 true
8.5’ 20” 2300 13 gal 153 true
2.5’ 25x2 18 gallon around 165 true
 
Whitewaterraftr said:
Here’s a couple of my numbers for a O520 180 with 850’s and a Horton.

2.5’ 19” 2200 10gal 130 true
10.5’ 19” 2200 11gal 144 true
8.5’ 20” 2300 13 gal 153 true
2.5’ 25x2 18 gallon around 165 true
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These are in knots and from a TAS computer?
 
I find using the E6B in flight rather difficult, especially if bumping around in the cockpit. So I built a TAS table using excel and an electronic E6B. During a flight I just look at the altimeter, outside air temperature, and the airspeed indicator, then find the correct column on the chart to correct CAS to TAS. When I built this chart I centered it on 140 CAS but I use 120 most of the time. I should redo the chart but I haven't felt the need.IMG_20231109_095917546.jpg
The bold altimeter setting provdes correct numbers for altitude and air temperature as shown. For different altimeter settings, simply move over one or two columns as required. As an example for an altimeter setting of 31.0, OAT of 10°C, and 4500 feet 120CAS would be 120+6 = 126TAS

Hope this helps.
 
William Pete Hodges said:
I find using the E6B in flight rather difficult, especially if bumping around in the cockpit. So I built a TAS table using excel and an electronic E6B. During a flight I just look at the altimeter, outside air temperature, and the airspeed indicator, then find the correct column on the chart to correct CAS to TAS. When I built this chart I centered it on 140 CAS but I use 120 most of the time. I should redo the chart but I haven't felt the need.View attachment 130869
The bold altimeter setting provdes correct numbers for altitude and air temperature as shown. For different altimeter settings, simply move over one or two columns as required. As an example for an altimeter setting of 31.0, OAT of 10°C, and 4500 feet 120CAS would be 120+6 = 126TAS

Hope this helps.
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That's a super nice chart, and appears to be mph which seems quite reasonable with the 520
 
As my buddy once said "any aircraft can reach Mach 1 if you try hard enough!".....:D
 
Stewartb said:
I fly low. 140-145 mph with 29” mains and BBW tailwheel. On 800s and an 8” tailwheel I saw 185mph at 1000’ MSL. I have a Pponk and 86” 3-blade. It’s been too long since I had a 470. No memory.
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I don’t intend to hijack the thread. I am beginning to research an off airport plane for my son in law. Is the P.Ponk basically a 470+50 carbureted, or is there more modification than that? Do you know any enthusiast discussion forums for these planes? It will be a 180, 182 on floats with wheel gear, or a 185.
 
DKirkpatrick said:
Hello. I know there's a ton of variables like how good of a pilot you may be... but what is a real TAS for a Cessna 180, with an O-470R? And I know the airplane's designed to be a hauler, etc., but want to just know a good planning speed for a three hour flight, 7000' average?
thanks for the coaching in advance.
dan
Click to expand...
130 knots at gross weight and 65% power. You pick up about another 5 knots as fuel is burned.
 
The other day I was flying back home from Smiley Creek. 8,500 17.5", 2300rpm, OAT 60, 129kts to 132kts true.
 
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