Re: FRANKLIN?

[Mi Vida Loca]

At 07:47 PM 12/3/98 -0500, you wrote:
>At 02:52 PM 12/3/98 -0800, susan dawson wrote:
>>I just talked to a gentleman from Winchester Va. who has fitted a 120hp
>>franklin engine to an ercoupe!!!! It even fits the stock mount! does
>>this give anyone ideas?......jolly
>
>Yeah. Of smacking someone in the back of the head.
>
>The Ercoupe is a lovely, balanced design. It all plays together.
>In particular, the design depends on a balance of power and
>torque to make it work right (that's why the engine offset
>is a bit unconventional).
>
>Fred designed a 65HP airplane. To pull the electrical systems and
>accessories that were gradually added 75HP was certainly welcome.
>And 85HP made sense to drag metal wings. And 90 was probably better
>as amenities and density altitude went up. Coupe owners with O-200
>engines seem to be really happy with the balance. That's already
>a 70% power increase from the original, though!
>
>So 20% more power over the tried and true, evolved, tested, maximum
>seems to have no real use other than to change a good design into
>an indifferent one. At some point, returns diminish. Increased
>cruise and rate of climb taper off, fuel consumption starts to
>out-pace the capacity of the stock tanks, and useful load goes
>DOWN because the structural limits are the limiting factor, not
>climb ability.
>
>Though it might fit on the original mounts, what about cooling?
>20% more power means 20% more heat. Where's it going to go?
>Coupes aren't known for having a lot of extra flow up there.
>
>And what about Franklin parts? It would be generous to describe
>the history there as 'spotty.' There have been years and years
>where Franklin owners hoarded every part they could find. Granted,
>some things (like cranks) are getting wierd for the Continentals,
>but not that wierd. And it seems more likely that some enterprising
>soul may begin to make new ones, versus what could happen with
>Franklin/Pietzl (are they in or out of business this week?).
>
>For the price of getting a F120 in place, you probably could fit
>the world's best O-200 conversion, Millennium cylinders,
>new Bendix electronic ignition, super-duper valves and heads,
>and all.
>
>Seems like the C90 or O-200 are perfectly adequate to move an
>Ercoupe or Alon right along in the way the designer intended,
>while preserving the fundamental character of the airplane.
>Why mess with it and chance turning a wonderful bird into a
>dud?
>
>Greg

Guess you've never tried to get out of a short field on a +100 degree day or tried to climb out of a 5000' MSL field on a warm day. Trust me you can't have too much climb performance. Now as for cruise performance and fuel consumption. Well there is defiantly a diminishing return on HP vs speed. Fuel consumption need not suffer. There is nothing that says you have to use all that extra HP for cruise. Throttle back and Fuel consumption should be roughly the same. I suspect the fuel consumption is roughly the same HP for HP between the 2 engines and therefore flying at the same speeds they will use the same amount of HP to drag the airframe through the sky. The increase in fuel burn only is a factor when pushing harder. An old hot rod adage holds true with aircraft as well. When you have too much power you have just enough... Just because you have extra HP doesn't mean you have to use it but it is damn nice to have the reserve. Now as for all the flowery crap about how well balanced the coupe was with 65 hp. The first coupe flew with an A-40. Now Fred was smart enough to know more HP would increase the safety margin. So ERCO produced a few 60HP inline engines (the coupe looked really good with that in line) but didn't prove economical to produce. The A-65 just happened to be the biggest commercial engine available at the time that would work with the airframe. So actually with the C-90 it is actually a 225% increase over what the Coupe was originally designed for. Fred didn't seem too upset about that. If he wasn't upset or concerned about it maybe you should reassess your evaluation of the situation. I guess if you always fly off 3000 foot runways and rarely fly above 5000 feet you have a good point. Not all of us do that though.


Dave
41 Charlie
Dave's Ercoupe Page
www.flash.net/~dmprosvc/dave
ICQ # 1388138
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