flyingcheesehead
Touchdown! Greaser!
I woke up this morning and it was -4F. High for today was supposed to be 1F.
Sounds like a good day for a flight.
However, it's also that much more of a learning experience to push that particular part of the envelope. So, I'll tell the story and welcome comments.
The plane had been flown and was parked in a heated (though not exactly warm) hangar. I did my preflight inside. All checked out well except the nose gear inflation, which was quickly fixed. I hopped in the plane so I'd be ready to go as soon as the tow bar was off.
Same old routine - Master, beacon (though I left it off to leave max battery for the start), mixture, tank, prime, CLEAR!, start.
Well, in theory anyway.
First time, I did my normal trick of one shot of prime and then crank while putting in the second shot, which usually works great. This time, it burned through the prime fuel and then quit. Going from experience, I pulled the carb heat, then did two shots prior to cranking. It went a little longer, but still quit. Hmmm. Maybe the intake air is so darn cold it's still too lean? So, I primed, cranked, and it caught and I fed it a couple more shots with the primer when it started to sputter (at maybe 20 seconds and 1 minute after initial cranking). Then, it stayed on.
For warmup purposes, I was on the ground idling (and doing the runup) with the cowl flaps closed for 19 minutes before oil temp came off the peg. There's been debate about that, but while I won't wait for the oil temp at an OAT of 40F because I know it's reasonably warm, I will wait when it's 0F because it might be darn near solid!
After the engine started, it was at first very reluctant to speed up. Idle was low, and when I'd add just a hint of throttle, it'd start to sputter with or without carb heat. It took about 2.5 minutes before I could get it up to 1000 RPM. After I got it there, I gave it carb heat again, which after another minute or so took it up to 1300 RPM. Taking away the carb heat would drop it to 1200 RPM and over a period of about 30 seconds I could hear very small backfiring-type noises (thanks to ANR, never would have heard them otherwise). Adding carb heat again would make the noises go away, again after a short period of time.
After a while, the engine warmed to the point where it wasn't behaving "funny" any more, so I called for my clearance and taxi.
Runup was very odd. First, the mag check. Going to either mag resulted in an RPM drop of ~400 RPM, way outside normal limits, but there was no roughness whatsoever. EGT also went through the roof. My theory is that the air was so cold that due either to temperature or mixture reasons (or both), it was burning so slowly with only one mag that it was still burning on the way out. I also did a full-power runup just to be sure I really was getting full power on both mags.
Second thing about the runup that was odd... The prop. Oil must have really not wanted to move! I'd have to pull pretty far back on the knob for it to do anything, and then it'd get down to around 1200 RPM (after I was already pushing the knob back in) and just sit there for about 5-6 seconds before coming back up to full power, though it didn't sound like it was the prop causing this, but the engine itself. I don't think I have a theory for that one.
Anyway, though things were different than normal, I still felt like the engine was working well, so off I went. Still didn't manage to peg the VSI, but I got 1800 fpm sustained before I went to cruise climb. I went all the way up to 7500 feet, where the OAT was cold enough to freeze hell and the air was so thick I was actually indicating 130 KIAS. I usually get 130 KTAS in this plane, so that was impressive.
Another odd thing about the super-thick air: Full rich was lean of peak at 7500! When I began to lean, the EGT went down. Wow. It did appear that full rich was close to peak, so I did lean it just a hair.
I also had about a 45-knot tailwind component, and terminated flight following 10 miles from RAC only 24 minutes after takeoff.
Winds were 27012G24 for my landing on runway 32. In spite of that, I managed a really good landing (my pax was impressed and said so, especially after the wild ride down final).
We have no cowl plugs or engine blanket for the plane so I parked away from the wind with the control lock installed. There was somewhat of a wind shadow near the building as well.
Upon my return to the airport an hour and a half later, I inquired about the price of a preheat. $63! (Is it just me, or is that outrageous?) I decided to feel the cylinders first, and good thing - They were cold, but not ambient-cold. Just not quite as warm as my hands. So, I didn't get the preheat.
The engine started easier than the first time, though the primer behaved funny: When pulling it out, I could feel the fuel filling it for the first 3/4 of the stroke, then it'd pull out easier and no more fuel would enter it. Odd. After an almost identical repeat of the warming-up period from the first leg of the trip, right down to the 19 minute warmup, I took the runway for the return trip.
On the way back, I only went to 3000 MSL to stay out of the ferocious headwind (and I still only made around 100 knots GS).
Remember that full rich was lean of peak at 7500, or apparently so? Well, I decided to see if the same was true at 3000. Dumb, dumb, dumb. I'd barely touched the knob when the engine coughed and darn near quit. Scared the crap out of me! I'll need to do some hangar-flying over that one, mainly just thinking through emergencies a bit because the sense of panic was a lot greater than I'd ever imagined. Luckily, the cough lasted maybe 3 blades (=~0.1 sec @ 2400 RPM) but it was enough. Yikes.
I managed another very good gusty crosswind landing at MSN (27009G16, runway 32) and parked the plane. The line guys showed up right away to put it in the hangar, and I dragged my flight bag out to the car, which was showing an OAT of -7F at 0 AGL.
Brrrrrrrrr.
Sounds like a good day for a flight.
However, it's also that much more of a learning experience to push that particular part of the envelope. So, I'll tell the story and welcome comments.
The plane had been flown and was parked in a heated (though not exactly warm) hangar. I did my preflight inside. All checked out well except the nose gear inflation, which was quickly fixed. I hopped in the plane so I'd be ready to go as soon as the tow bar was off.
Same old routine - Master, beacon (though I left it off to leave max battery for the start), mixture, tank, prime, CLEAR!, start.
Well, in theory anyway.
First time, I did my normal trick of one shot of prime and then crank while putting in the second shot, which usually works great. This time, it burned through the prime fuel and then quit. Going from experience, I pulled the carb heat, then did two shots prior to cranking. It went a little longer, but still quit. Hmmm. Maybe the intake air is so darn cold it's still too lean? So, I primed, cranked, and it caught and I fed it a couple more shots with the primer when it started to sputter (at maybe 20 seconds and 1 minute after initial cranking). Then, it stayed on.
For warmup purposes, I was on the ground idling (and doing the runup) with the cowl flaps closed for 19 minutes before oil temp came off the peg. There's been debate about that, but while I won't wait for the oil temp at an OAT of 40F because I know it's reasonably warm, I will wait when it's 0F because it might be darn near solid!
After the engine started, it was at first very reluctant to speed up. Idle was low, and when I'd add just a hint of throttle, it'd start to sputter with or without carb heat. It took about 2.5 minutes before I could get it up to 1000 RPM. After I got it there, I gave it carb heat again, which after another minute or so took it up to 1300 RPM. Taking away the carb heat would drop it to 1200 RPM and over a period of about 30 seconds I could hear very small backfiring-type noises (thanks to ANR, never would have heard them otherwise). Adding carb heat again would make the noises go away, again after a short period of time.
After a while, the engine warmed to the point where it wasn't behaving "funny" any more, so I called for my clearance and taxi.
Runup was very odd. First, the mag check. Going to either mag resulted in an RPM drop of ~400 RPM, way outside normal limits, but there was no roughness whatsoever. EGT also went through the roof. My theory is that the air was so cold that due either to temperature or mixture reasons (or both), it was burning so slowly with only one mag that it was still burning on the way out. I also did a full-power runup just to be sure I really was getting full power on both mags.
Second thing about the runup that was odd... The prop. Oil must have really not wanted to move! I'd have to pull pretty far back on the knob for it to do anything, and then it'd get down to around 1200 RPM (after I was already pushing the knob back in) and just sit there for about 5-6 seconds before coming back up to full power, though it didn't sound like it was the prop causing this, but the engine itself. I don't think I have a theory for that one.
Anyway, though things were different than normal, I still felt like the engine was working well, so off I went. Still didn't manage to peg the VSI, but I got 1800 fpm sustained before I went to cruise climb. I went all the way up to 7500 feet, where the OAT was cold enough to freeze hell and the air was so thick I was actually indicating 130 KIAS. I usually get 130 KTAS in this plane, so that was impressive.
Another odd thing about the super-thick air: Full rich was lean of peak at 7500! When I began to lean, the EGT went down. Wow. It did appear that full rich was close to peak, so I did lean it just a hair.
I also had about a 45-knot tailwind component, and terminated flight following 10 miles from RAC only 24 minutes after takeoff.
Winds were 27012G24 for my landing on runway 32. In spite of that, I managed a really good landing (my pax was impressed and said so, especially after the wild ride down final).
We have no cowl plugs or engine blanket for the plane
so I parked away from the wind with the control lock installed. There was somewhat of a wind shadow near the building as well.Upon my return to the airport an hour and a half later, I inquired about the price of a preheat. $63! (Is it just me, or is that outrageous?) I decided to feel the cylinders first, and good thing - They were cold, but not ambient-cold. Just not quite as warm as my hands. So, I didn't get the preheat.
The engine started easier than the first time, though the primer behaved funny: When pulling it out, I could feel the fuel filling it for the first 3/4 of the stroke, then it'd pull out easier and no more fuel would enter it. Odd. After an almost identical repeat of the warming-up period from the first leg of the trip, right down to the 19 minute warmup, I took the runway for the return trip.
On the way back, I only went to 3000 MSL to stay out of the ferocious headwind (and I still only made around 100 knots GS).
Remember that full rich was lean of peak at 7500, or apparently so? Well, I decided to see if the same was true at 3000. Dumb, dumb, dumb. I'd barely touched the knob when the engine coughed and darn near quit. Scared the crap out of me! I'll need to do some hangar-flying over that one, mainly just thinking through emergencies a bit because the sense of panic was a lot greater than I'd ever imagined. Luckily, the cough lasted maybe 3 blades (=~0.1 sec @ 2400 RPM) but it was enough. Yikes.
I managed another very good gusty crosswind landing at MSN (27009G16, runway 32) and parked the plane. The line guys showed up right away to put it in the hangar, and I dragged my flight bag out to the car, which was showing an OAT of -7F at 0 AGL.
Brrrrrrrrr.
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I'm not sure if the last two cylinders would be properly cooled with a 172-style kit. Or, maybe we just don't have one. Who knows.
