Good afternoon all of you experts out there. I have a 1969 Cessna Cardinal with a 0-360A2F engine with a Powerflow exhaust. The guy that I purchased the airplane from says to firewall the throttle when cruising but that seems crazy to me. My normal cruise flight last for approx. 2 hours between 8500 and 9500. Thanks in advance for your help.
Cessna Cardinal Cruise RPM
- Thread starter Flybynite
- Start date
JimNtexas
Pattern Altitude
- Joined
- Dec 21, 2006
- Messages
- 2,259
- Location
- Austin, Texas
- Display Name
Display name:
Jim - In Texas!
I firewall my C177RG throttle in cruise and pull back the rpm to 2300 or so.
Our non-turbo motors aren't making anything close to max power above 3 or 4 thousand feet.
Our non-turbo motors aren't making anything close to max power above 3 or 4 thousand feet.
- Joined
- Dec 5, 2010
- Messages
- 5,161
- Display Name
Display name:
GeorgeC
I recently went through the exercise of figuring out at what altitude does WOT become less than or equal to 75% power. Is there a rule of thumb for the typical NA piston single spam can?
TulsaWeather
Pre-takeoff checklist
If it's less than 75% power, it won't hurt that 360.
How fast do you want to cruise? That engine is continuous duty, as long as you get adequate cooling you're not going to blow anything up, but you will see increased cylinder maintenance along with high fuel cost. If you are renting wet and they tell you to run it WOT, go for it. If you own it or rent dry, I wouldn't.
poadeleted20
Deleted
- Joined
- Apr 8, 2005
- Messages
- 31,250
Start by reading the Performance section of the owner's manual. You'll note that in the 6500-9500 altitude range, you'll be at or near full throttle to get "normal" cruise power of 65-75%.
Oh, I missed the altitude, yeah, at that altitude WOT is normal unless you've got turbos.
By the time you hit that altitude, wide open throttle is already going to represent a reduced cruise power setting because there is less air up there. Is yours fixed pitch or constant speed? FP you may need to back off a touch in cruise if you have a 'climb prop'.
Let it rock, keep the RPM below redline, lean appropriately, you'll be fine wherever you decide to set power.
Jaybird180
Final Approach
Interesting....I thought all those Cardinals were CS Props.
bnt83
Final Approach
I didn't read all the repossesses but most are entirely wrong for a fixed pitch equipped Cessna 177 with an O-360A2F
I have the 68 O-320 version with powerflo, I run 2400 - 2500 most of the time unless I want to save a few gallons per hour.
O-360s don't strike me as efficient so I can't imagine what your fuel flows are at those settings ( ~10 gph?) ouch $$$...
I have the 68 O-320 version with powerflo, I run 2400 - 2500 most of the time unless I want to save a few gallons per hour.
O-360s don't strike me as efficient so I can't imagine what your fuel flows are at those settings ( ~10 gph?) ouch $$$...
Last edited:
poadeleted20
Deleted
- Joined
- Apr 8, 2005
- Messages
- 31,250
First year (or two?) had a 150 HP O-320 and fixed prop -- real dog. The switched to a 180 HP O-360 and c/s prop, which turned it into a very nice plane. Not sure if the first year of O-360 was FP or CS or if they did that later. So, when talking Cardinals, you need to know which propulsion package is involved.
Nope. Not until the RG or the 177B. The 177 does not have a CS prop, nor does the 177A.
The reputation as a dog for the 150 HP versions is partly deserved. But the reputation was also based in part on people not flying them per the POH, but instead flying them exactly like they would a 172. Flying the numbers in the book made a big difference, and the numbers were not the same as for the 172 that shared the same numbers. At least that is what Cardinal Flyers Online says, and they tend to know their Cardinals.
There was the 177A model that had the 0-360 without a CS prop. The 177B added the CS prop, and those, IMHO, are the ones to own. (Which I do.)
Jaybird180
Final Approach
The OP needs to specify then.
topgun260
Pre-takeoff checklist
- Joined
- Dec 21, 2013
- Messages
- 303
- Display Name
Display name:
Topgun260
It's not about an opinion it's about whats in the owners manual. How fast do you want to go and how much fuel do you want to burn? Normal cruise is usually 75% power and I would imagine somewhere around 10gph. In the 8500'-9500' range my guess is that you would need full throttle in most conditions to make the RPM to give you that 75% power. If you don't want 75% power than pull back the power to the fuel flow you like. The RPM that will give you 75% power will change depending on conditions so just because 2700 RPM may give you 75% power at 8500' indicated altitude today, doesn't mean that it will do the same tomorrow or any other day if the conditions are different. Check your owners manual for the proper engine settings for the conditions you are flying in.
bnt83
Final Approach
That all depends on what you want.
If I could pick between a 150/160 horse 172 or 150 horse 177, I'd pick the 177.
If I had to have a 4 seat Cessna but more power than a 172, I'd skip the 177B altogether and get an O-470 powered 182 and burn car gas. The 177B can't do that.
cgrab
Pattern Altitude
My Cardinal has an O-320 and after hearing several presentations at OSH I flew back at WOT at altitudes from 7500 down to 3500 and I leaned per the presentations.
On the way up I throttled back but didn't lean much below 3500. I used 8.1 gal/hr on the way up and 6.9 gal/hr on the way back.
I'm a believer in WOT from take off until you get to your destination and in pulling the big red knob to rough then back in a little.
On the way up I throttled back but didn't lean much below 3500. I used 8.1 gal/hr on the way up and 6.9 gal/hr on the way back.
I'm a believer in WOT from take off until you get to your destination and in pulling the big red knob to rough then back in a little.
bnt83
Final Approach
If you can keep the RPMs below redline more throttle to ya.
I typically see 10-11 gallons per hour, 70 degrees WOT at 1,300 feet MSL. I cruise around 6.5-7 GPH
I haven't bought any 100LL this year meaning I burn about $25 per hour in gas, carry my wheelchair in the baggage, (35 pounds) two big bags on top of that ~400 pounds in the front seats with 48 gallons of fuel. I rarely see climbs under 500 FPM @ 80 to 90 MPH IAS WOT between 1200 and 4500 msl. Temperature is a big player just like any other airplane.
You try climbing a 1968 177 at 172 speeds your shooting yourself in the foot. The thin wing doesn't like it.
Last edited:
poadeleted20
Deleted
- Joined
- Apr 8, 2005
- Messages
- 31,250
Running that high power in cruise is OK as long as you keep RPM below redline (and how accurate is your tach with the fixed pitch prop on a C-177?), but your fuel consumption is going to be up a good bit. In the normal cruise power range, increasing power increases speed by about 3% for every 10% increase in fuel flow. If you're OK with that, go for it. Otherwise, at $6/gallon, I'm running about 65-70% power for what I think is a good balance of speed and economy.
gismo
Touchdown! Greaser!
Engine HP is roughly proportional to MAP and RPM. MAP usually runs about 1inHg less than the ambient air. So starting with 29 inHg at sea level and losing 1 inHg per 1000 ft of altitude you'll hit 75% at about 7500 and 65% at something like 10,000 DA if the RPM is constant. But with a CS prop we usually reduce RPM from max during cruise flight by 10-15% so those altitudes are more like 6500 and 8500.