Thanks. I understand the "timely; but smooth" application of appropriate control when fan up front stops (aka: panic). Also substantiates the fact that the fan up front keeps the pilot cool as each time it has quit on me I start sweating immediately. Dan C
On Jun 10, 2010, at 12:55 PM, William R. Bayne wrote: > > Hi Dan, > > Thanks for the kind words. I have always regarded the Ercoupe as a fine > cross country machine if one understands its capabilities, limitations and > their own limitations. > > A properly functioning mixture control is absolutely necessary to achieve > maximum possible engine performance and efficiency at higher altitudes. The > procedure in the Ercoupe Instruction Manual works fine, except that I have > found benefit below 5,000' PA (where density altitude at 100ºF may be > 7,000'). > > EGT and/or CHT instrumentation is inexpensive (I used a single-probe non-TSO > EGT). One has access to much more important information with sensors on all > cylinders and a selector switch controlling a single indicator for nominal > additional investment. I believe intelligent use of such by the pilot allow > him/her to best achieve that magic point where the "best power", "best > economy and "best airspeed" curves cross for a given coupe. I believe an > engine so operated is more likely to achieve or exceed TBO because the > operator has the ability to be aware of, diagnose and remedy many common > engine problems before their adverse effects accumulate to the point of > failure. > > With the relatively low power-to weight ratio of the Ercoupe (as compared to > most "modern" certificated designs) proper leaning can make the difference > between success and failure taking off and climbing out from high altitude > airports in the summer. I should have mentioned that. > > To illustrate the "difference" our mixture control makes, My wife and I once > returned from somewhere and decided to overfly our airport and continue to > one near the beach for something to eat. That was sufficient "break" from > normal procedure that I forgot to return the mixture to Full Rich before or > during descent from "high lean cruise" position. Engine performance seemed > normal until I reduced power for descent from pattern altitude to land and > the "fire went out" in the engine. Even though the prop continued > "windmilling", that transition was definitely a "holy s**t" moment. > > Of course the power smoothly returned upon my timely but smooth return of the > mixture control to "Full Rich" (without backfire), but it was a very clear > reminder of the fact that a properly operating Stromberg mixture control is > effective to the purpose intended and not to be ignored. I have also never > forgotten to enrich in descent again ;<) > > Regards, > > William R. Bayne > .____|-(o)-|____. > (Copyright 2010) > > -- > > On Jun 10, 2010, at 11:43, Caliendo Dan wrote: > >> Good discussion, William, and I agree. My experience with mountain flying >> has all been in fuel injected engines >> and I'm wondering if you can use the leaning the mixture (which gives you >> significantly more power at high density >> altitude) in an Ercoupe with a carburetor. Seems the mixture leaning is a >> pretty slow process in my Ercoupe; but I've >> not used it at altitude (shucks, have had the coupe for over 2 years and >> haven't been above 3,000 ft yet : >). >> Dan C >> >> >> On Jun 9, 2010, at 10:45 PM, William R. Bayne wrote: >> >>> >>> Hi Dennis, >>> >>> You don't say what prop you have, but I will assume it is the correct size >>> metal McCauley of "standard" pitch. >>> >>> If so, several considerations. You will have slightly better performance >>> (for a given temperature) than the 415-D figures (1) because you will be 80 >>> lbs. lighter, because the metal prop has slightly better efficiency (which >>> slightly increases the resulting rate of climb) and because I am consulting >>> the take-off figures in the 415-E Flight Manual (because you have the 85hp >>> engine instead of the 75hp in the D). >>> >>> I have crossed the Continental Divide several times each way flying from >>> Phoenix via Lordsburg (the southern route) or to Albuquerque (the northern >>> route. Fly the mountains early, because afternoon thunderstorms build fast >>> and often in the afternoon heat...not a good time to be there, aside from >>> the turbulence. >>> >>> This was infinitely more challenging utilizing VOR and pilotage than GPS >>> today. VOR coverage below 10,000' in that area is poor, so one had to >>> achieve accurate enough results with pilotage (despite iron deposits >>> influencing the compass) after leaving Phoenix VOR reception to intersect >>> the rather limited "circle of VOR coverage" of the few VORs en route to >>> Albuquerque. >>> >>> With a normally healthy engine, the "book" (interpolated) suggests an E >>> model with a wood prop at 1400 lbs. and 100ºF will require 4513' of runway >>> before liftoff. That isn't the "whole story", though. You can lift off in >>> "ground effect" on a given day (few air masses are exactly the same) and >>> find the plane won't climb and loses altitude in the gentlest bank. That >>> can put you in deep yogurt real quick, so carefully review conditions in >>> depth before deciding to take off and never attempt a takeoff in which >>> success is at all doubtful. This is easier said than done. >>> >>> Again, with reference to 415-E data, the chart interpoation suggest a climb >>> rate at 4500' PA and 100ºF of 282 FPM at best rate of climb. I am NOT >>> bragging in revealing dodging a church steeple well away from the Lordsburg >>> airport because our rate of climb had essentially ceased at 90 mph and 100' >>> off the ground. Instead of establishing my normal "cruise-climb" I should >>> have set the plane up for best rate of climb to get higher under those >>> conditions. Another time, departing Albuquerque near noon I found terrain >>> rising more rapidly than we were in three possible directions. A "trick" I >>> discovered that day is to look for buzzards and/or cumulus clouds. These >>> mark rising air, and the boost in climb is free except for the time off >>> course and circling upward in a stationary thermal. >>> >>> It is not unusual to find an inversion over an airport, in which the air >>> temperature actually rises as you climb. Such a "cap" of air is what traps >>> smog in the Los Angeles, CA basin. Once through that "cap" with the >>> superheated air nearer the ground (which typically has less "lift" in it) >>> below you, climb performance is much better. >>> >>> Where there is rising air there is also sinking air. Always approach >>> higher ground at a 45º angle so you can turn away with only a 90º turn >>> should you encounter a downdraft there to maintain good terrain clearance. >>> We had to search up and down a high mesa on our course to find more lift, >>> but eventually climbed to over over 10,000' that day en route to Dalhart, >>> TX and East. >>> >>> It would suggest you plan your trip to arrive at the airports you speak of >>> late in the day and depart in the early morning. That makes a big >>> difference because high altitude airports usually enjoy low humidity and >>> that gives you 60ºF early morning takeoff conditions before an afternoon >>> high of 100ºF. Alternately, depart with just enough fuel to get to a lower >>> airport before filling the tanks. If you calibrate your tanks, keep >>> records of your fuel consumption, and monitor it several times each leg >>> this is quite predictable and safe. In good VFR conditions, half the nose >>> tank's usable fuel is plenty of reserve (unless you are simultaneously >>> learning use of the GPS on a given flight ;<) >>> >>> Taking off from lower but hotter airports in Arizona in the summer, I have >>> taken of with full fuel and left my wife on the ground to see how much >>> "lift" is in the air mass present. Unfortunately after returning to get >>> her, the engine is thoroughly "heat soaked" and oil temperatures can get a >>> bit dicey before reaching cooler temperatures aloft. Fortunately today's >>> oils continue to lubricate adequately at temperatures above redlines still >>> recommended for our little Continentals. >>> >>> There are options available to the proficient and knowledgeable pilot that >>> can greatly increase the utility of relatively low performance aircraft. >>> At some point experience significantly reduces the big bag of luck that new >>> pilots dip into frequently. But knowledge and quick thinking is the best >>> "insurance". These are the words of a Private Pilot, not a CFI or >>> professional aviator. Results may vary. >>> >>> Regards, >>> >>> William R. Bayne >>> .____|-(o)-|____. >>> (Copyright 2010) >>> >>> -- >>> >>> On Jun 9, 2010, at 13:03, Dennis wrote: >>> >>>> My brother & I are planning a cross country trip (with my 85hp 415C) which >>>> will require one or two take offs at airports with altitudes 4000 to 4500 >>>> feet and temperatures up to 100 degrees F. Density altitude probably at >>>> about 6500 feet or possibly higher. Runways are 6000 feet long and the >>>> Ercoupe will be loaded to maximum at 1320 pounds. >>>> >>>> Considering all the above information, the 415-D flight manual charts >>>> (pages 10 and 11) show that it will take 3950 feet to take off and we will >>>> climb at 330 feet per minute. My problem is that I have never done this. >>>> My normal take off roll when I am alone and it's 70 degrees F. takes me >>>> 1000 feet or less. What I really need is someone who is very experienced >>>> in these long take off rolls to help convince me that the Ercoupe will >>>> really take off at 3950 feet and then climb at 330 feet per minute. Of >>>> course, if it isn't at take off speed at 3950 feet of the 6000 foot >>>> runway, I still have time to abort the take off. >>>> >>>> I will really appreciate any information or advice you can provide. >>>> Thanks, Dennis Hatfield >>>> >>>> >>>> >>>> ------------------------------------ >>>> >>>> Yahoo! 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