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Ed
Burkhead
ed -at- edburkheadQQQ.com (change
-at- and remove QQQ)
-----Original Message-----
From: William R. Bayne [mailto:[EMAIL PROTECTED]
Sent: Wednesday, March 09, 2005 5:56 PM
To: Ed Burkhead
Subject: WRB Re: [COUPERS-FLYIN] Carb heat connection to throttle
From: William R. Bayne [mailto:[EMAIL PROTECTED]
Sent: Wednesday, March 09, 2005 5:56 PM
To: Ed Burkhead
Subject: WRB Re: [COUPERS-FLYIN] Carb heat connection to throttle
RLYFLYIN (WRB via Ed Burkhead's computer-I can't post directly)
Please send responses directly to the list or to me, Bill Bayne @
<[EMAIL PROTECTED]>
Hi Ed (WRB talking),
The incident you describe occurred in the fall of 1941 and is related on pages 186-187 of Fred's autobiography. It explains that the Jeep's carburetor air was drawn from a warm place inside the engine compartment ,and that a long oil warm-up had "...set up the carburetor icing" responsible for the forced landing.
We can reasonably infer that the Jeep was not, at the time equipped with a "regular carburetor air heater" since Fred was clear that "...after that we used (one)...".
In the fall of 1941 continental powered coupes were being produced, so it is unlikely Fred would have performed any carb heat experiments on the Jeep (which was powered by the Erco IL-116 inverted four). I have seen no information to suggest any pre-war coupes were sold with the carb heat interconnected with the throttle, and would hope anyone with such information will share it with us.
A photocopy of an undated handwritten draft by Fred entitled "Educational Literature For Ercoupe Pilots" states (in part), starting on p. 28:
"(7) LANDING
(A) Use and Operation of Carburetor Air Heat.
The Ercoupe is equipped with both a manual automatic heat control.
The automatic control is located on the engine air intake duct and is attached to the carburetor throttle control arm.
The automatic heat control is adjusted to put heat full on when throttle is set so that the engine is turning 1750 R.P.M. with the aircraft in level flight at approximately 70 M.P.H. The heat is turned off automatically at approximately 75 M.P.H., ..75 M.P.H.. (and above). Automatic carburetor heat control is installed as a safety precaution against the pilot neglecting to operate the manual control while in a power off glide. Carburetor icing due to lack of carburetor heat has been the cause of many accidents in light plane operation.
It is recommended in spite of the automatic control that the manual control be used. This recommendation is made because a pilot on his landing approach may apply power beyond 1750 R.P.M. aand in that case would automatically shut the heat off.
If the manual control is set for heat the heat remains on regardless of the throttle setting."
This would seem to suggest that Fred's experience with carburetor ice in the Jeep was instrumental in his subsequent decisions to (1) install a proper carburetor heater and (2) invent a way to assure his installation afforded maximum protection against icing even in the hands of an uninformed or inexperienced pilot or owner.
Fred's system, as designed, was essentially one either fully ON or fully OFF, without meaningful operation in between these extremes (as is good practice). So, in my opinion, one might choose to remove (337?) a system installed on all postwar Model 415-C Ercoupes as produced and originally certified in order to save weight; but not for safety.
Regards,
William R. Bayne
<____|-(o)-|____>
(Copyright 2004)
--
On Mar 9, 2005, at 2:04 PM, Ed Burkhead wrote:
Andy,
I remember Fred Weick telling a story about the automatic carb heat system he was testing in the “Jeep”. (The Jeep was the Coupe prototype they used for lots of development tests.
It turns out that while carb heat can melt ice, partial carb heat can bring the incoming air right into the best range for making ice. (Too cold OR too warm and you get no ice – the middle temperature will make LOTS of ice in the wrong conditions.)
Fred told the story of flying into a regional airport and getting carb ice, on final if I remember right. My memory of his story includes the approach being over water right to the runway and it was a hairy moment. Their testing showed it was caused by the automatic carb heat being in a partially-on state.
I think they removed the automatic carb from being an option after that. You might reconsider keeping that option installed. Let’s see what the experts here on the list say.
Ed Burkhead
http://edburkhead.com/
ed -at- edburkheadQQQ.com (change -at- and remove the QQQ)
I know you believe you understand what you think I said, but I am not sure if you realize that what you heard is not what I meant. (Jim, AKA Midnight Plowboy)
-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]
Sent: Wednesday, March 09, 2005 12:26 PM
To: [EMAIL PROTECTED]; [email protected]
Subject: Re: FW: WRB Re: [COUPERS-FLYIN] Carb heat connection to throttle
I still have the automatic carb heat linkage hooked up on my coupe. It's set up much like the accelerator pump linkage on most automotive carbuerators. Most of the time it's right where it should be, however if I know I'll be landing at a grass / dirt strip somewhere, I simply put a slight bend to the "automatic" part of the linkage so that it isn't functional. Back home just bend it back.
Andy Pomeroy
2417H in Arlington, WA
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