The International Cessna 170 Association

hilltop170 wrote:That is AWESOME!

Lots of questions come to mind like, do you think 20,000' is the limit?, was there any wave lift?, was it all due to the engine or maybe the MT prop?, was the engine really quiet?, were the controls mushy?, what were the engine temps doing?, what version cabin heater do you have?, did it keep the cabin warm?, etc?, etc?.

I know there is more to the story and it would make a great read in the 170 News, hint, hint.

I wish I'd spoken to you before doing the flight, because I'd have been more diligent about collecting data.

To answer your questions, I think 20000 wasn't the absolute limit, but we hung there for a long time. We might still have had 20 fpm, and I might have been able to squeeze a bit more altitude with smoother flying or leaning to best power. But we were basically down to zero climb. Interesting that 20k was our goal, and there may have been some unconscious bias. Objective test flying is difficult, and I don't claim to have the skill.

The winds were probably 60 knots, much stronger than forecast, and we were right where mountain wave would occur, but I don't think that's what got us the altitude. I've flown in mountain wave and orographic lift, but we didn't feel any. It was just a straight climb from Longmont northeast, with steadily decreasing ROC as we went. Never felt like we were getting a free ride, nor did we feel anything external in the descent. Also, we've had the airplane as high as 17500 several times before and always thought 20000 was in reach, particularly in the winter. But I could be wrong about that. There were a few lenticulars off to the south.

The engine didn't seem quiet, I think because I had the RPM at full and because my door seals don't seal very well.

The airplane has the stock 1954 heat setup, and it worked; we weren't cold. I was wearing a long sleeve shirt and hoodie sweatshirt. No gloves.

Engine temps were high considering the low power output. Oil temp was 180, where it always is, but CHTs were high. I richened the mixture to keep CHTs below 380. They'd have gone over 400 if I'd leaned to best power.

Controls were definitely mushy. We were just hanging there, and anything that changed airspeed caused us to descend.

While we were up high I took off my O2 for about 15 minutes to see how I felt. Mainly just unpleasant. I felt slightly headachy, annoyed, and had feelings of anxiety. Definitely not euphoric. I bungled a call to Center, so I knew I was impaired. Back on O2, I noticed my peripheral vision improved and I just felt better. I did feel more tired than usual for the rest of the day, though. For the record, my son is commercial/instrument and was PIC for the flight.

Bruce, I thought about you a lot while we were way up there, knowing how much you dislike flying high!

We did shoot a GoPro video. Here are a couple of screenshots and a Foreflight screenshot from about 18500.

DaveF wrote:[..Bruce, I thought about you a lot while we were way up there, knowing how much you dislike flying high!...

Unlike a certain Member from Looeasyana (who is permanently high at S.L.)

Dave did the DEN Center controller make any comment on your ground speed? If it were me I would have had to! Nice job!

What was the spread of CHT temperatures at altitude. For example was no1 very cool and no 3 very hot. I have a 4 banger up front also and have been listening to other owners very carefully regarding engine performance . It seems there is a design flaw with the R/H intake shape and distance from no1 cylinder. Could be doing a “repair” to my intakes , but still doing the research.

N8293A wrote:Dave did the DEN Center controller make any comment on your ground speed? If it were me I would have had to! Nice job!

Delta....have an eye out for Cessna traffic at 19000ft....Delta ....Cessna at 190......what speed.......19kts...

Dave, you realize of course that the altimeter installed in most 170s is only certified to 20K. How do you know your needle didn't hit a STOP?

N8293A wrote:Dave did the DEN Center controller make any comment on your ground speed? If it were me I would have had to! Nice job!

No mention at all. I guess he didn't think twice about my ability to stay within 3nm of the VOR, just as I requested!

George, I guess the next time I get a 91.411 check I'll ask the tech to run it up to 25000. On a more serious note, this makes me think about what I want for ADS-B. UAT is only good to 18000.

ghostflyer wrote:What was the spread of CHT temperatures at altitude. For example was no1 very cool and no 3 very hot. I have a 4 banger up front also and have been listening to other owners very carefully regarding engine performance . It seems there is a design flaw with the R/H intake shape and distance from no1 cylinder. Could be doing a “repair” to my intakes , but still doing the research.

I think the CHTs were about as uneven as they usually are, but I'd have to download the data from the JPI to see. CHTs 3 and 4 got pretty warm and I had to richen the mixture to stay below 380. The induction is pretty uneven and I can adjust EGT and CHT spread with very small throttle or prop movements. Cylinders 1 and 2 run richer than 3 and 4.

DaveF wrote:

ghostflyer wrote:What was the spread of CHT temperatures at altitude. For example was no1 very cool and no 3 very hot. I have a 4 banger up front also and have been listening to other owners very carefully regarding engine performance . It seems there is a design flaw with the R/H intake shape and distance from no1 cylinder. Could be doing a “repair” to my intakes , but still doing the research.

I think the CHTs were about as uneven as they usually are, but I'd have to download the data from the JPI to see. CHTs 3 and 4 got pretty warm and I had to richen the mixture to stay below 380. The induction is pretty uneven and I can adjust EGT and CHT spread with very small throttle or prop movements. Cylinders 1 and 2 run richer than 3 and 4.

Note to Continental operators: It should be obvious that Dave is operating a Lycoming which numbers it's cylinders differently than TCM.

Thats really cool Dave. Thanks for sharing.

When your groundspeed went negative, how did you know? Was there a "-" sign in front of the number or maybe the velocity vector pointed behind the plane?

KAYO GAY HORN. . . Ima gonna haf tu go retro on ya. Mebee i outer togots lil bonus fer beein braver than smart buts in thu seeson uv winner in thu rokie mts its coal aroun 20,000 feets sos i wanna git doun quick but divin at 105 an still goin upll frieze ure brassuns. soze iffn ive gots permunun los of funxun in places ill blame that ride! thu choyce uv beein stil live is buttern bein froz an ded.

Wow! He has been in the box so long I cant even read or understand what he says. Y'all will have to go back a few years to find Ole Gars dictionary!

Another day and another dollar here in Sabine Parish, had me flying for the Chief Investigator for the Local DA. There had been a shooting at a neighborhood honkytonk. The shooter ditched his rifle in the lake 3 or 4 miles from the bar. The Investigator wanted a photograph of both the bar and the site where they recovered the weapon. I took the right side door off the 170 and we proceeded to climb to an altitude where he could get both places in the frame. He finally signaled that he was ready. We had not prepared for the cold at 16500'! Boy it was freezing. He took his photos then we made haste to get to a lower, warmer altitude. I thought of spinning her down but I had never spun with the door off the right side so had no idea what it would be like. just did a steep spiral to the left! Later times, when we did those photo sessions, no matter what altitude, we threw in a couple of coats in the back seat!

c170b53 wrote:

Oh boy, I can't wait for the rebuttal

Ole Gar never rebuts but some buttals aint happe less theys pokin funat a helpless kripple. ima has sum histry with buttals and sumtime ima tou lazie tu tink uop wayz tu git bakattem.

hilltop170 wrote:When your groundspeed went negative, how did you know? Was there a "-" sign in front of the number or maybe the velocity vector pointed behind the plane?

The velocity vector, as portrayed by the ForeFlight airplane, was pointing the wrong way!