C85 and Marvel carb Ice

[PA1195]

E6B computer or round slip stick...I busted my PP check ride in 1975 because I never used the rotating plastic gizmo for ground speed and wind correction. Examiner wanted a demo which I couldn't do. Instead I would draw a line on the chart and mark expected timed checkpoints. If I was off left-right-ahead-behind I knew there was a wind. Back then there was no requirement for ground school just a written test. I had flown for a year and about 200 hrs and decided to get legal. I have the same E6B and still have never used that feature in 7500 hrs but my GPS has one if needed.

Gary

[Hank Jarrett]

Gary, I used toe do the same thing and drew the wind triangle right on the chart. It was easier to see if you had the vector directions right and I NEVER made a mistake doing it that way. One of my instructors looked at me like I had two heads when I showed him. I had to learn to use the Wiz Wheel for the test (where I DID make mistakes!) I have even done a wind vector solutions on the chart in flight with no problems.

Hank

[PA1195]

That's Old School Hank but it's what was taught by some then. Ex-military pilots that learned in the air what was actually happening versus pre-flight briefing. One instructor wrote on his left hand all the info. Then when it became apparent the forecast winds aloft were different and fuel range changed he marked the chart with the rough correction angle and checkpoint vector diagram you mention. Vector and matrix analyses were taught in math and physics classes then but maybe that''s changed. One of my instructors said if we couldn't figure it out with math draw a picture to convince ourselves. Works ok today.

Gary

[Jim Herpst]

I had a Cessna 140 that had an 85 with the Marvel. Every time I flew I go carb ice. I no longer own that problem. I heard it could have been a cracked( hairline) venturi. I think earlier in this thread there were some good suggestions that might help pinpoint a problem.... I recall asking the C120/140 club for any suggestions and got a lot of lame "never happens to me" or might be your climate" . Good job on actually trying to help isolate the problem as he may very well have a problem...not a measurement problem either.

[PA1195]

I keep suggesting a manifold pressure gauge as an indicator of carb ice. If it can't be stopped at least don't let it stop you.

Gary

[JimC]

"I had a Cessna 170 that had an 85 with the Marvel".

I think this is the first 170 I've ever heard of running an 85.

The 85s make more ice than a refrigerator.
I just adid carb heat any time below 1900 rpm.

[Jim Herpst]

"I had a Cessna 170 that had an 85 with the Marvel".

I think this is the first 170 I've ever heard of running an 85.

The 85s make more ice than a refrigerator.
I just adid carb heat any time below 1900 rpm.

Sorry, Edited it to reflect A 140. DUH