Franklin Sport 4 engine

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Dan Thomas

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If you only worked on certified airplanes you may not be aware of Ellison throttle body injectors, light weight starters, electronic mags, alternators and permanent magnet generators that weight only 3 pounds and put out 30 amps. These all reduce weight by at least 20 lbs. some available 20 years ago. Welcome to the world of homebuilt airplanes! Kitplanes mag is the best source of the latest technology.
I've been into homebuilding since 1972. Was a charter member of a new EAA Chapter that year. Got my PPL in 1975. Commercial in 1993, IFR in 1995, Flight Instructor in 1999, Aircraft Maintenance Engineer license in 2000. Had several aircraft projects.

How long have you been in homebuilding?

The Ellison was, I believe, an outgrowth of the Posa carb, which was a big deal in the '70s, but it would never fly with certified airplanes because it would dribble fuel when the engine wasn't running, so the fuel had to be shut off at shutdown and turned on right at startup. That's too much to expect of the average pilot. Shoot, they barely understand carb icing and carb heat. The Ellison is famous for being fussy and hard to get set right. Traditional float carbs were settled down a hundred years ago, even the stupid certified Marvel Schebler carbs that persist with a bunch of hassles even after numerous ADs. My ancient 75-year-old Stromberg runs better than those MS things. The Posa was touted as an ice-free carb, which was, of course, totally wrong, and there were problems. Any time you restrict airflow you cause a pressure drop and therefore temperature drop, and anytime you atomize fuel into an airstream you get an evaporative cooling on top of that. Only fuel injection, at the intake ports, is relatively ice-free.

I replaced numerous old starters with lightweight PM starters on many airplanes as a mechanic, all on certified ships. When I retired four years ago, reliable electronic mags were not yet widely available, and from the discussions over on Pilots Of America, it appears they still aren't. Reliable, that is. The Surefly stuff is giving many pilots fits. Some of them quit soon after installation. E-Mag/P-Mag don't appear to be certified but they've been around awhile. They had plenty of troubles early on, too. There are other EI systems, most of them only on Experimentals. Lycoming's iE2 engine is the only certified engine I know of with EI and EFI. All of this points out the difficulty of getting electronic stuff reliable enough to satisfy the regulators. Magnetos are primitive, but that also means they are simple and robust and will not make trouble IF they are properly maintained according to their manufacturers. The only mags I had trouble with were those that had manufacturing defects, or that had not been maintained, and NEITHER of those factors reflect on the magneto's principles. On the other hand, electronic stuff in airplanes gives constant headaches. 90% of all hassles are electrical or electronic. I was taught that in Power Mechanics in high school in 1968, and I have found it true every since.

PM alternators are light, but they get like that by replacing the field coil (rotor coil) with permanent magnets. That means that the only method of regulation is to run the output through a variable resistance, now a big transistor, to regulate the system voltage, and that is a primitive way of doing things that traces its roots back a century or more to a time before there were electromechanical or electronic regulators that vary field current. They used stacked carbon discs, put under varying pressure by a heavy spring, opposed by a big current-sensing coil, to vary the resistance. A PM alternator is at full load all the time, in contrast to a field-regulated alternator or generator. That means wasted power, lost as heat.

I built a tiny PM generator for my Jodel, using a small ball-bearing PM motor, and a regulator designed around an LM117 voltage regulator chip. Spun it with a 3-inch propeller. It produced awesome radio noise no matter how much filtration I put into the system. Took it out and went back to charging the battery occasionally. All it ran was the radio.

Plane Power makes some smaller, lighter alternators, but most serious owners want more power, not less. Alternator outputs are based on some engine RPM, typically at least runup RPM, which means that at idle they won't generate full power, so the alternator has to be larger to accommodate night operations. Glass-panel airplanes also consume more power, day or night. The Garmin G1000 consumes 9 amps from its standby battery when the main system fails, and that's for just the PFD, one Com and the transponder, and the engine instrumentation. The MFD and the rest of the stuff go dark. The whole system likely takes 20 amps, at least, all the time.

Alternators replaced generators a LONG time ago, in the mid 1960s, in both cars and airplanes, when suitable diodes became available. Until then, we were stuck with generators of 25 or 30 or 35 amps that couldn't keep the lights on during night ground operations. (It didn't help that in those days the radios were often still using vacuum tubes, greedy things that ran the battery flat in ten minutes.) Little outputs like that might be fine for today's average puddlejumper homebuilt, but the guy that wants more utility is going to need more power. I have installed the 70-amp Plane Power systems for owners, taking out the larger and heavier 60-amp alternators.

12 years ago I was replacing all the landing and taxi lights on all the flight school's airplanes with the Whelen LED lights. Got tired of the short lives of the incandescents, and the calls at night from the school complaining that a light was dead and they wanted to go flying. Those LEDs fixed everything, and also extended the life of the switches in the panel. I am not unfamiliar with new technologies.

I am waiting for a safe, inexpensive lithium battery. No, not for an airplane. For the electric trolling motor on my canoe. That big heavy lead-acid deep cycle battery is a killer for my old back. And I'd like to put a larger electric troller on my big boat and get rid of the noisy kicker. Rather listen to the birds and breeze in the trees as I troll along, not a constant chatter, along with exhaust fumes.

Edit: Sentence clarified to avoid confusing certain people. One word added:

Any time you restrict airflow you cause a pressure drop and therefore temperature drop...

Sigh. A whole career in ruins due to missing one word. Life is rough.
 
Last edited:

pfarber

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Location
Dollywood
How long have you been in homebuilding?

I know lots of people that have worked for decades at a job/hobby that I wouldn't trust with a dull butter knife.


"Any time you restrict airflow you cause a pressure and therefore temperature drop, "

See what I mean? This sentence does not mean what you think it means. All of those years you touted as being an Uber mechanic lost with one poorly worded post.
 

Dan Thomas

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Joined
Sep 17, 2008
Messages
7,346
I know lots of people that have worked for decades at a job/hobby that I wouldn't trust with a dull butter knife.


"Any time you restrict airflow you cause a pressure and therefore temperature drop, "

See what I mean? This sentence does not mean what you think it means. All of those years you touted as being an Uber mechanic lost with one poorly worded post.
Back to school, Mr. Farber. You flunked physics.

1654136344601.png

Read all about it:
Carburetor Icing

Carburetor Icing (Causes, Symptoms, and Prevention) - Pilot Institute

What Pilots Need To Know About Carburetor Ice - Severe VFR

Now, prove me wrong by proving all of that wrong.

There is so much assumptive knowledge that people pick up somewhere that is totally wrong, and instructors of every sort battle it regularly. Some folks have held some ideas so tightly for so long that they become unteachable.

I was a college instructor, too, teaching Aircraft Systems. This stuff was part of the syllabus, for the 12 or 13 years I taught it, sometimes in both semesters.
 
Last edited:

Mflyer

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May 2, 2021
Messages
28
I've been into homebuilding since 1972. Was a charter member of a new EAA Chapter that year. Got my PPL in 1975. Commercial in 1993, IFR in 1995, Flight Instructor in 1999, Aircraft Maintenance Engineer license in 2000. Had several aircraft projects.

How long have you been in homebuilding?

The Ellison was, I believe, an outgrowth of the Posa carb, which was a big deal in the '70s, but it would never fly with certified airplanes because it would dribble fuel when the engine wasn't running, so the fuel had to be shut off at shutdown and turned on right at startup. That's too much to expect of the average pilot. Shoot, they barely understand carb icing and carb heat. The Ellison is famous for being fussy and hard to get set right. Traditional float carbs were settled down a hundred years ago, even the stupid certified Marvel Schebler carbs that persist with a bunch of hassles even after numerous ADs. My ancient 75-year-old Stromberg runs better than those MS things. The Posa was touted as an ice-free carb, which was, of course, totally wrong, and there were problems. Any time you restrict airflow you cause a pressure drop and therefore temperature drop, and anytime you atomize fuel into an airstream you get an evaporative cooling on top of that. Only fuel injection, at the intake ports, is relatively ice-free.

I replaced numerous old starters with lightweight PM starters on many airplanes as a mechanic, all on certified ships. When I retired four years ago, reliable electronic mags were not yet widely available, and from the discussions over on Pilots Of America, it appears they still aren't. Reliable, that is. The Surefly stuff is giving many pilots fits. Some of them quit soon after installation. E-Mag/P-Mag don't appear to be certified but they've been around awhile. They had plenty of troubles early on, too. There are other EI systems, most of them only on Experimentals. Lycoming's iE2 engine is the only certified engine I know of with EI and EFI. All of this points out the difficulty of getting electronic stuff reliable enough to satisfy the regulators. Magnetos are primitive, but that also means they are simple and robust and will not make trouble IF they are properly maintained according to their manufacturers. The only mags I had trouble with were those that had manufacturing defects, or that had not been maintained, and NEITHER of those factors reflect on the magneto's principles. On the other hand, electronic stuff in airplanes gives constant headaches. 90% of all hassles are electrical or electronic. I was taught that in Power Mechanics in high school in 1968, and I have found it true every since.

PM alternators are light, but they get like that by replacing the field coil (rotor coil) with permanent magnets. That means that the only method of regulation is to run the output through a variable resistance, now a big transistor, to regulate the system voltage, and that is a primitive way of doing things that traces its roots back a century or more to a time before there were electromechanical or electronic regulators that vary field current. They used stacked carbon discs, put under varying pressure by a heavy spring, opposed by a big current-sensing coil, to vary the resistance. A PM alternator is at full load all the time, in contrast to a field-regulated alternator or generator. That means wasted power, lost as heat.

I built a tiny PM generator for my Jodel, using a small ball-bearing PM motor, and a regulator designed around an LM117 voltage regulator chip. Spun it with a 3-inch propeller. It produced awesome radio noise no matter how much filtration I put into the system. Took it out and went back to charging the battery occasionally. All it ran was the radio.

Plane Power makes some smaller, lighter alternators, but most serious owners want more power, not less. Alternator outputs are based on some engine RPM, typically at least runup RPM, which means that at idle they won't generate full power, so the alternator has to be larger to accommodate night operations. Glass-panel airplanes also consume more power, day or night. The Garmin G1000 consumes 9 amps from its standby battery when the main system fails, and that's for just the PFD, one Com and the transponder, and the engine instrumentation. The MFD and the rest of the stuff go dark. The whole system likely takes 20 amps, at least, all the time.

Alternators replaced generators a LONG time ago, in the mid 1960s, in both cars and airplanes, when suitable diodes became available. Until then, we were stuck with generators of 25 or 30 or 35 amps that couldn't keep the lights on during night ground operations. (It didn't help that in those days the radios were often still using vacuum tubes, greedy things that ran the battery flat in ten minutes.) Little outputs like that might be fine for today's average puddlejumper homebuilt, but the guy that wants more utility is going to need more power. I have installed the 70-amp Plane Power systems for owners, taking out the larger and heavier 60-amp alternators.

12 years ago I was replacing all the landing and taxi lights on all the flight school's airplanes with the Whelen LED lights. Got tired of the short lives of the incandescents, and the calls at night from the school complaining that a light was dead and they wanted to go flying. Those LEDs fixed everything, and also extended the life of the switches in the panel. I am not unfamiliar with new technologies.

I am waiting for a safe, inexpensive lithium battery. No, not for an airplane. For the electric trolling motor on my canoe. That big heavy lead-acid deep cycle battery is a killer for my old back. And I'd like to put a larger electric troller on my big boat and get rid of the noisy kicker. Rather listen to the birds and breeze in the trees as I troll along, not a constant chatter, along with exhaust fumes.

Edit: Sentence clarified to avoid confusing certain people. One word added:

Any time you restrict airflow you cause a pressure drop and therefore temperature drop...

Sigh. A whole career in ruins due to missing one word. Life is rough.
I got my PPL in 1965, Commercial in 1970, A&P in 1974, IA in 2009, and worked 38 years for a major airline. Member of EAA since 1969, owned 7 certified airplanes. Now in my 80's, for my last project I'm working on an MFI-9HB (homebuilt version of a Bolkow Jr).

As far as interest in homebuilts goes, I'm not into glass panels, night flying and 200 mph airplanes that cost $100K and up. I'll settle for 120 mph on steam gauges.

I can't argue with anything you say and your experience in General Aviation goes way beyond mine. Reliability of new products for the homebuilt airplanes are for experimental only and are proven reliable with years of use in the field. The same could be said for FAA certified products as evidenced by AD notes.
 

Yellowhammer

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Born In Alabama, reside: Louisiana (unfortunately)
I have flown every year of C-172's from 1956 ( built Nov, 1955 , 226th built) to 1979. The 1956 was the best handling, ROC , Takeoff, etc.
We restored the 1956 to factory new from a bare fuselage in a chicken house and wings and engine in another building and everything else in boxes.
Started on Sept 3th and trailered to airport with the wings off on Dec 3 rd. Flew it for about 4 years and sold.
Also have flown most years of C-150's and the first year of 1959 is the best year. Of all the C-182's I have flown , the earliest is a 1959, and it was also the best flying.
Of the C-310's, I like the 1959 the best.


That's a lot of flying Pops. How many hours have you logged sir?
I bet you have six or seven log books!

-Yellowhammer
 

Dan Thomas

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Joined
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Messages
7,346
Reliability of new products for the homebuilt airplanes are for experimental only and are proven reliable with years of use in the field. The same could be said for FAA certified products as evidenced by AD notes.
Yup. Composites got their start in homebuilding. Glass panels, too. Even one certified aircraft engine is a converted car engine: the Thielert diesel, based on a Mercedes. Homebuilders often lead the way. Lycoming built their iE2 engine long after homebuilders were using auto-based EI and EFI.

I'm no electric-airplane fan, but if it succeeds it might just be at the hands of a clever homebuilder, but he'll have to have some sort of magic to make it practical. Magic like Steve Wittman or Leeon Davis had, getting terrific speed out of small engines.
 

pfarber

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Messages
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Location
Dollywood
Back to school, Mr. Farber. You flunked physics.

View attachment 126101

Read all about it:
Carburetor Icing

Carburetor Icing (Causes, Symptoms, and Prevention) - Pilot Institute

What Pilots Need To Know About Carburetor Ice - Severe VFR

Now, prove me wrong by proving all of that wrong.

There is so much assumptive knowledge that people pick up somewhere that is totally wrong, and instructors of every sort battle it regularly. Some folks have held some ideas so tightly for so long that they become unteachable.

I was a college instructor, too, teaching Aircraft Systems. This stuff was part of the syllabus, for the 12 or 13 years I taught it, sometimes in both semesters.
Lol you're just so anxious to be the smartest person in thr room, but you fail at the obvious

If you restrict the flow to ZERO T
then there is no movement.

Also wings are not Venturi. You cannot explain how an airplane flies by burinelli alone. Yes, there are papers written about it. You should spend some time educating yourself about it.

Nice try, still a hard fail.

Next question.
 

Pops

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That's a lot of flying Pops. How many hours have you logged sir?
I bet you have six or seven log books!

-Yellowhammer
Just trying to fly as many different aircraft as possible all of my life. My grandson is doing the same. He's 36 years old now and flown for a living since getting his instructor rating. Got his ATP a couple days after turning 24 and was hired by the airlines a few days latter. Last I ask he said somewhere between 55 to 60 different airplanes . How has 6 type rating. Gulfstream on order, so he will be getting another one for that. Has flown PPY, P-51, B25, F-5 , etc. I gave him his first flying lesson at 10 years old and he learned on a 1943 Stearman. My total is between 85 to 90.
 

Dan Thomas

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Joined
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Messages
7,346
Lol you're just so anxious to be the smartest person in thr room, but you fail at the obvious

If you restrict the flow to ZERO T
then there is no movement.

Also wings are not Venturi. You cannot explain how an airplane flies by burinelli alone. Yes, there are papers written about it. You should spend some time educating yourself about it.

Nice try, still a hard fail.

Next question.
Enlighten us. You are as clear as mud. You cannot command respect; you have to earn it, and you must provide references and links for what you believe to be true. Otherwise, it's just ad hominem attacks.

And I know that wings are not venturis. Where did I say they were?
 
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Yellowhammer

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Born In Alabama, reside: Louisiana (unfortunately)
Just trying to fly as many different aircraft as possible all of my life. My grandson is doing the same. He's 36 years old now and flown for a living since getting his instructor rating. Got his ATP a couple days after turning 24 and was hired by the airlines a few days latter. Last I ask he said somewhere between 55 to 60 different airplanes . How has 6 type rating. Gulfstream on order, so he will be getting another one for that. Has flown PPY, P-51, B25, F-5 , etc. I gave him his first flying lesson at 10 years old and he learned on a 1943 Stearman. My total is between 85 to 90.


Pops,

Thank you for sharing that information with me/us. That is amazing and extremely special. I know you are proud of your grandson no doubt. I knew you had a lot of knowledge and I always make sure to pay close attention to the comments that you make on here. So far in my young flying career I have flown 6 different airframes.
I consider myself blessed to have six. Always looking for the next one though. Thank you again for sharing that about you and your grandson. Safe skies to the both of you sir.

-Yellowhammer
 

Mflyer

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Messages
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I find it hard to believe the Franklin Sport 4 engine is not being produced as a kit of engine parts to be assembled for home built airplane builders or a shop the way it was 50 years ago. No FAA TC is needed. The Franklin Sport 4 could be upgraded to solid state ignition, automotive spark plugs, Bing carb and other external changes similar to the Jabiru 3300 engine selling at an affordable $20,000. The Sport 4 has 235 c.i. (125 hp) but weighs the same as the Continental O-200 about 210 lbs. The small Continental and Lycomings are 1940s production technology. From the responses I've got, some are negative about the Jabiru 3300 engine quality. Yes they had more than their share of problems initially but the Generation 4 version solved them. Kitplanes magazine describes the details.
This photo was found in a 1970 Sport Flying magazine showing the kit built Franklin Sport 4 engine for $1300. For homebuilts only.
 

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BJC

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I probably mentioned this before: the 4 cylinder display engine at Oshkosh several years ago had the hole in the mounting ear way off center. I was surprised that anyone would display it.

See below.


BJC
 

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Pops

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Like to know the history of that. Looks like some of my mistakes.

Thought I made a mistake onetime, but I didn't.
 
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Vigilant1

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This photo was found in a 1970 Sport Flying magazine showing the kit built Franklin Sport 4 engine for $1300. For homebuilts only.
Well, $1300 in 1970 would be $10,000 if this kit were sold today, if their cost increases mirrored general inflation over the last 52 years.
I think I'd probably choose something else if I needed 100-120 HP. Parts and good instruction (Mr Wynne) to build an airworthy Corvair derivative would be competitive with that. Heck, Bill Clapp (Azalea Aviation) will build and sell anyone a running 100 HP engine for $10.5k, or a 120HP engine for about $13k.
 
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TFF

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Memphis, TN
At the Continental booth at Oshkosh a couple of years ago, one of the diesels was displayed on the nose of a Lancair. Ooos and ahhs, then oh. The angle iron and all thread used to slap it on the nose was a bummer.
 

Pops

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Would have been nice if the Flanklin engine cylinders were drilled for 18mm spark plugs instead of the 14mm. On the 6 cylinder that is 12 spark plugs that now have a price of almost $70 each.
What I use in my 1835 cc VW engine.
 
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