Luscombe Weight and Balance

[Boundary Waters]

I recently purchased part of an 8A... It was an aircraft well known to me and it was undergoing a rather major annual, which explains how the funds I had available to invest got me in the door. (I just completed my Private in a Taylorcraft, so I am "untainted" by electrical systems or nose-draggers.)

There are lots of discussions about weight, and staying light. For instance in my plane one double entry and three small errors on the previous W&B decreased the useful load by sixteen pounds.

So, I thought I would toss out some known numbers on this one particular Luscombe 8A with an A-65, Ceconite covered wings and a brand new PMA'd 14 gallon fuel tank.

The original registration listed the empty weight as being 750 lbs. (drawn from the factory W&B).
810.97 lb aircraft +14.75" (11809) as weighed <-- NEW (2021) Certified Empty Weight and CG
-- > 757.78 lb on main wheels + 2.91" (2205) as weighed
-- > 52.19 lb on tailwheel + 186.9" (9754) as weighed
BUT after deducting 85.9 lb (from 16 listed items) +27.05" (2323.4) the frame was
-- > computed to weigh 725 lb +13.08" (9485.6) < -- includes the "whisky" compass
1 lb spinner --48.5 (--48.5)
1 lb gascolator --20 (--20)
0.5 lb air speed indicator --6 (--3)
1 lb altimeter --6 (--6)
0.2 lb oil pressure indicator --6 (--1.2)
0.2 lb oil temperature indicator --6 (--1.2)
1 lb tachometer --6 (--6)
30 lb 6.00-6 4-ply mains w/tubes +2.91 (+87.3) < -- Note: the narrower factory wheels are 21 lb.
6 lb carpet +14 (+84)
4 lb upholstery +14 (+56)
6 lb seat cushion +18 (+108)
4 lb headliner +18 (+72)
8 lb seat back +20 (+160)
2 gal, 12 lb unusable fuel +20 (+240) < -- previously double counted
3 lb ELT +46 (+138)
8 lb. Scott 3-24-B, 6 x 2.00, steerable tail wheel +183 (+1464)
< -- the tail wheel has a 6 lb. exchange weight on the TCDS so the solid skid must have weighed two pounds.
EDIT: Some arms are estimates (eg: upholstery, carpet, headliner) but the more critical total is not.

 

[Bell206]

There are lots of discussions about weight, and staying light.

So what is your question?

Some datum points are estimates

FYI: the datum point is the benchmark, i.e., the zero reference for any arm measurement from that datum. That arm distance for an item installed is just as critical as the weight.

 

[RyanShort1]

For instance in my plane one double entry and three small errors on the previous W&B decreased the useful load by sixteen pounds.

Which is why the first step is to actually put it on some certified scales, like I asked to be done before I bought my Luscombe. My plane's empty weight is 769...

 

[Boundary Waters]

Electrical systems add weight.

The A&P who was doing the annual had various parts and pieces from a 'Gremlinmeister' with a C-85 engine and he let me weigh them.
32 lb gel cell battery in fiberglass case
13.5 lb alternator and harness
12.2 lb starter
1.2 lb voltage regulator
2 lb copper wires
1 lb switches and fuses
5 lb position lights and harnesses
5 lb beacon and harness
-- > 71.9 lbs < -- it was vintage equipment, not newer lighter stuff, but new starters and alternators are advertised at 10 lbs. so they are not that much lighter.

He had a few radios 1.0 lbs. to 2.5 lbs.
Two speakers 1.0 lbs. and 1.1 lbs.
A couple vaccume instruments 2.5 lbs. and 3.0 lbs.
Some antennas 0.1 lbs. to 0.5 lbs.
A whisky compass like mine weighed a pound.

He also had paperwork on a couple of engines... (I didn't actually weigh these.)
178 lb Continental A-65 with magnetos, spark plugs, ignition leads, and no fuel pump.
184 lb Continental C-85 with magnetos, spark plugs, ignition leads, but no other accessories.
214 lb Continental O-200 with magnetos, spark plugs, ignition leads, but no other accessories.

And props...
13.5 lb for my Sensenich W76CK44
23.4 lb for a smaller metal McCauley 7154 (for the C-85)

 

[Boundary Waters]

The arms (thank you) for the headliner, carpet, and upholstery are the least exact, but can't be far off. The seat cushions are pretty spot on, the instruments are pretty much stuck in those holes in the panel so...

 

[Bell206]

The arms (thank you) for the headliner, carpet, and upholstery are the least exact, but can't be far off. The seat cushions are pretty spot on, the instruments are pretty much stuck in those holes in the panel so...

Okay. So what answers are you looking for? I don't see any questions?

 

[martym]

750 is on the heavy side for a rag wing 8A. Subtracting 16 lbs puts it a little closer to what I would expect. Does it have a metal prop?

 

[Boundary Waters]

Okay. So what answers are you looking for? I don't see any questions?

There isn't a question yet, there are many postings that I have read concerning weights. It's a pain to disassemble a working airplane to figure out how much the headliner weighs so (sane) people don't. My plane was apart so I weighed everything.

In time I'll probably wear people out with my questions. Right now I am thinking about the fact that fuselage station 4 has reinforcements that conform to Luscombe dwg. 58730-C and there are "unemployed" rear strut float attachment fittings...

(A musing or maybe a rhetorical question.) Do you suppose that the difference between what I can legally haul if I mount 92-1400s versus 60-1320s is just an error, an oversight by Luscombe not to ask for an increased gross weight, a reflection that two different demonstration flights had different loads on board, or was the CAA giving "credit" because the bigger floats were more aerodynamic or had better handling characteristics on the water?

 

[Bell206]

It's a pain to disassemble a working airplane to figure out how much the headliner weighs so (sane) people don't. My plane was apart so I weighed everything.

You're overthinking this from the wrong side. Most sane people reweigh an aircraft to get a current certified empty weight... then work at seeing where they can reduce the weight. However, based on what you have listed above your options to remove an item are very limited. So perhaps start with a good empty weight and see what you can legally remove first. Otherwise you're just spinning your wheels.

In time I'll probably wear people out with my questions.

That will only depend on the type of questions you ask.

 

[Boundary Waters]

I was being facetious, but it doesn't translate well on-line. I don't have any issues with weight or weight and balance. (Edit: my 8A is eligible for an increase to 1310 lbs., a pointless waste of time and money given the below numbers.) Right now its gross weight is 1260 lbs. which is just fine for my purposes.

Lightest weight -- (forward CG limit + 13.60)
811 lb airframe + 14.75 +11962
7.5 lb oil -- 24 --180
150 lb people + 20 +3000
No baggage + 40 +00
968.2 lb aircraft no use fuel +15.27 +14782
72 lb fuel + 40 +2880
1040.2 lb aircraft full fuel + 16.99 +17662

Heaviest weight -- (rear CG limit + 18.80)
811 lb airframe + 14.75 +11962
7.5 lb oil -- 24 --180
300 lb people + 20 +6000
69.8 lb baggage + 40 +2792
1188 lb aircraft no use fuel +17.34 +20573
72 lb fuel + 40 +2880
1260 lb aircraft full fuel + 18.62 +23453

(I see the formatting doesn't survive.)

 

[Boundary Waters]

750 is on the heavy side for a rag wing 8A. Subtracting 16 lbs puts it a little closer to what I would expect. Does it have a metal prop?

I imagine 750 lbs. was with Grade A cotton and dope. I don't have the original equipment list, just the original empty weight on the original registration. It was recovered with Ceconite later-- most likely getting a little lighter in the process. The prop is a 13.5 lbs. wooden Sensenich W76CK44. It's a cruise prop, and a lot of people tell me it should really have a climb prop. Six or seven minutes to 3,000 foot AGL is pretty typical.

The two biggest comments I get are "change the prop" and "don't fly it from the right seat"-- which I do because the brakes are on the left side... So propping it from behind just works better if I fly from the right (or wrong as other's see it) seat, the instruments and engine controls are in the middle anyway.

EDIT: In a later post Magman suggested that it may originally been an intermediate covering with less dope, so maybe the Ceconite recover didn't decrease the weight as much as I thought it would have. Also the fuselage is painted and not polished aluminum.

My 724 pound airframe (I just found a one pound error in the new weights), with 21 pounds of tires, a six pound tail wheel, and four pounds of instruments should weigh 755 pounds. This includes the unknown weight of the modifications required for float installation, three point harnesses, and the waterproof skylight.

 

[Magman]

As others have said get it weighed and determine Empty Weight and CG.

ASSURE you have a good Equipment List that agrees with the airplane,It was

likely originally covered with Intermediate fabric that requires less dope to seal.

2 ply tires might have been original as well.

Fuselage polished or painted in 194?.

These can add up.

 

[Boundary Waters]

As others have said get it weighed and determine Empty Weight and CG.

ASSURE you have a good Equipment List that agrees with the airplane,It was

likely originally covered with Intermediate fabric that requires less dope to seal.

2 ply tires might have been original as well.

Fuselage polished or painted in 194?.

These can add up.

PAINT! Duh, It is painted, not polished.

It was just re-weighed and a new W&B created so the original list is somewhat irrelevant. Mostly a curiosity. The instruments are period, but they may not be original to the aircraft. It has float fittings and reinforcements, two three point inertia harnesses, and a modified skylight, those add a small amount of weight. It has slightly wider than stock 4-ply tires (nine pounds there). As you say it adds up.

 

[Magman]

Intermediate ( between Grade A and glider cloth) fabric had a finer weave so it

took less dope to seal.

I would say ceconite would be heavier.

“Original list is somewhat irrevelant “ is not a problem except as a curiosity as you

say.

The CURRENT Equipment List should reflect was was installed at time of weighing.

Otherwise it’s like a checking account but you don’t know which deposits and

withdrawals are affected.

 

[GeorgeC]

Welcome to PoA and congrats on a proper airplane.

 

[Bell206]

It was just re-weighed and a new W&B created so the original list is somewhat irrelevant.

Are you saying your new empty weight didnt come with an updated equipment list? Or that the updated list no longer matches the original equipment list?

 

[Boundary Waters]

Are you saying your new empty weight didn't come with an updated equipment list? Or that the updated list no longer matches the original equipment list?

The latter...

I have a 2021 Weight and Balance that gives a new certified empty weight and a new calculated empty CG point.

Both include 12 lbs. of unusable fuel, and items on a new equipment list.

I have xeroxes of PART of the factory (1940s) equipment list, and a complete copy of a 1970s reweigh-- maybe from when the wings were recovered in Ceconite-- it has an equipment list which is identical to the 2021 equipment list.

The airplane has actually been "officially" weighed at least three times:
750 pounds from the factory-- although my understanding is that this airframe may not have been individually weighed when new;
803 pounds in the 1970s-- 787 pounds after a few errors (the most significant being that 12 lbs. of unusable fuel were double counted) are backed out;
and 810.97 pounds in 2021. (Is this proof that gravity is intensifying-- it feels that way some mornings .)

The 2021 weight includes a one pound double entry for the whisky compass-- the only error that I see on it right now.

Prior to the 1970s reweigh the aircraft had at least four modifications (per TLDC or FA). Each added some weight to the airframe, accounting for some (or maybe all) of the 37 extra pounds. Most significant being "reinforcements at fuselage station 4 that conform to Luscombe dwg. 58730-C and rear (float strut) attachment fittings." A flat gasket and new plexiglas was fitted to the skylight. Two inertia reel lap and shoulder belts were installed with their "supporting cables and hardware," and the baggage compartment was lined and a net fitted.

Regarding the extra 23 pounds since the 70s reweigh: the new PMA'd 14 gallon fuel tank might weigh a little bit more than the original. The airplane has slightly larger and more durable main wheels and tires (9 lbs.) than stock-- but I don't know when these were added. The new upholstery and seat cushions may weigh a tad more than the originals did, and there may be a small amount of additional weight from cosmetically restoring the instrument panel and paint.

 

[Bell206]

he 2021 weight includes a one pound double entry for the whisky compass-- the only error that I see on it right now.

FYI: Since it was actually weighed, the double compass entry on the equipment list would only be a clerical error and not a weight error. So only the list would need to be corrected.

accounting for some (or maybe all) of the 37 extra pounds.

Regarding the extra 23 pounds

Given the time frame of your EWB history, these comparisons are not an exact science. There are inherent errors with the weight and balance process that can cause differences with the same aircraft outside of equipment changes. For example, when remove/install equipment the re-compute formula leads to minute errors considering the moment is purely a mathematical result, along with the number of decimals the values are taken out to, can over time change the weight value. On the actual weighing side you have weigh equipment variances from each time it was weighed as well as operator skill level. Plus several other possible issues. Regardless, over a period of 70+ years your EWB values seem to be inline with what you have researched plus any other “featured” errors.

So is this exercise solely for you to learn your aircraft in more detail, or are you trying to identify areas where you can reduce your current EWB?

 

[Boundary Waters]

So is this exercise solely for you to learn your aircraft in more detail, or are you trying to identify areas where you can reduce your current EWB?

The former, as well as just sharing numbers. Because lots of people share opinions that are not necessarily supported by real-world numbers.

For instance there is a Luscombe factory letter that describes the steps required to convert an 8A to an 8D-- which will allow a gross weight of 1310 lbs. (not 1320 lbs. as often stated). BUT, doing so costs 20 lbs. of the 50 lbs. gained in a labor and dollar intensive conversion.

(I'm a noob, but the airplane's majority owner has been around GA for 50 years, and the A&P for 40 years. So, I believe them-- okay, except for when the A&P was pulling my leg trying to convince a gullible girl that Ercoupes didn't have rudder pedals, and you flew Cubs from the back seat. Uh-huh, real good ones. )

I'm told that the A-65-8 is just fine. (It is exactly the same engine the Taylorcraft had.) That an A-75 (not a C-75 as often misstated) would just be an expensive paperwork improvement without any actual real-world performance gains. I have no complaints with the engine, the fuel system, or the gross weight. 1260 lbs. means that instead of 75 lbs. of baggage I am limited to 69.8 lbs. (5.2 lbs.). The majority owner and his wife probably max out at 320 pounds so they can still carry 49.8 lbs. of baggage aloft.

 

[Bell206]

The former, as well as just sharing numbers. Because lots of people share opinions that are not necessarily supported by real-world numbers.

Well good on you. Consider yourself in the top minority that take the time to learn the details. But don’t stop at learning just the aircraft as there is a lot more to learn if you so choose.

 

[Magman]

Hmm. Weight increases in the 50’s, 70’s , 80’s and now.

It sounds just like ME!

Contagious?

 

[Shepherd]

Weigh the plane!
Do the arithmetic!
I found two egregious mistakes in the logbooks going back decades.
The guy who put the C-85 and metal prop on the plane re-weighed it correctly.
Then he made a serious mistake in his weight and balance arithmetic. That was in 1958.
No one ever caught the mistake, and I'm assuming no one has ever bothered to actually sit down and calculate the W&B since then.
When I tried to do a W&B, the CG was back behind the baggage compartment. I had a couple other guys try it, with the same results.
After hours of reading through 73 years worth of log entries I spotted the mistake.
But I'm still going to have the plane re-weighed.

 

[Dan Thomas]

(I'm a noob, but the airplane's majority owner has been around GA for 50 years, and the A&P for 40 years. So, I believe them-- okay, except for when the A&P was pulling my leg trying to convince a gullible girl that Ercoupes didn't have rudder pedals, and you flew Cubs from the back seat. Uh-huh, real good ones. )

He wasn't pulling your leg.

 

[Dan Thomas]

Airplanes, like pilots, gain weight as they get older. Seems to be a law of physics.

I once did a prebuy on a Taylorcraft. The weight and balance showed a useful load of about 160 pounds. The owner didn't think anything of it. I never saw another W&B as far off as badly as that one.

 

[RyanShort1]

The assumed weights of the items installed are important, but meaningless compared to an actual physical weight under correct conditions. You may or may not fight interesting differences. That's when you start comparing the presumed stuff, and things like dirt, insect nests (mud daubers are a genuine problem in some parts of Texas) and paint that could be adding to to your empty number.

 

[Boundary Waters]

I was present on most days, cleaning things and absorbing as much as I could while "my Luscombe" was undergoing a very complete annual / fuel tank replacement / cosmetic restoration earlier this year. When it was all put back together the empty aircraft weighed 810.97 pounds-- 757.78 lb on the main wheels, and 52.19 lb on the tailwheel-- we computed the aircraft's CG as being +14.75". It was weighed after having the engine oil drained, on modern certified scales, properly leveled both side to side and fore and aft, and with fuel added-- by moi on a stepladder-- to the new tank until it exited the hose disconnected from the carburetor.

I imagine that it was the most accurate weight this aircraft ever had. Modern scales are more precise, and a great deal of care was taken. In almost every weight and balance that I have ever seen engine oil is included in the empty weight, only a minuscule amount is in mine. I also wonder about unusable fuel quantities. I was surprised that two gallons is unusable, double counting those twelve pounds as empty weight and fuel capacity becomes significant when one is getting close.

The empty weight is accurate, the moment and arm calculated, and the arithmetic checked. Sitting on three wheels, four quarts brings the oil level to the middle of the dipstick and twelve gallons allows just a tiny bit of room for expansion in the gas tank. So those numbers are accurate, and the weights and arms are official estimates.

I weighed several individual items removed from the airplane and replaced, as well as replacement items like the carpet and upholstery. Those weights are rounded to tenths-- the electronic scale went to eight digits-- and the arms are just close approximations. But as stated earlier: for W&B the total is what counts.

 

[Boundary Waters]

The assumed weights of the items installed are important, but meaningless compared to an actual physical weight under correct conditions. You may or may not fight interesting differences. That's when you start comparing the presumed stuff, and things like dirt, insect nests (mud daubers are a genuine problem in some parts of Texas) and paint that could be adding to to your empty number.

No daubers, but I probably shop-vac'd and scrubbed five pounds of dirt out of the airplane after the carpet and upholstery were removed .

 

[Boundary Waters]

He wasn't pulling your leg.

So you say . He also tried to convince me that Skymasters used different propellers on their two engines. 'Cmon, same engine, same prop... .

 

[Boundary Waters]

Airplanes, like pilots, gain weight as they get older. Seems to be a law of physics.

I once did a prebuy on a Taylorcraft. The weight and balance showed a useful load of about 160 pounds. The owner didn't think anything of it. I never saw another W&B as far off as badly as that one.

I learned to fly in an A-65-8 powered Taylorcraft. I'm 150 pounds, my instructor probably 180-190. Flying out of 600 to 1100 foot above MSL with 72 pounds or less of usable fuel and no baggage was never a problem, but I could easily feel the difference.

I guess all of these little airplanes were simply certified to whatever they weighed when the seats, fuel tanks, engine oil, and baggage compartments were full. Not that they couldn't have been certified at a different weight if they had been demonstrated at that weight. So today if extras are added-- bigger wheels, brakes, three point harness, etc.-- that just comes right off the bottom line.

 

[Bell206]

In almost every weight and balance that I have ever seen engine oil is included in the empty weight, only a minuscule amount is in mine. I also wonder about unusable fuel quantities.

It depends on the aircraft certification date and rules (CAA/FAA) what is required for the empty weight and balance record and is detailed in the TCDS/Aircraft Specification usually in Note 1.

I guess all of these little airplanes were simply certified to whatever they weighed when the seats, fuel tanks, engine oil, and baggage compartments were full. Not that they couldn't have been certified at a different weight if they had been demonstrated at that weight.

All those older little airplanes were certified to the same rule which had various weight formulas that would give different results depending on how the aircraft was constructed. However, you’ll also find that most of those older aircraft had increased EWB optional kits (like your Luscombe) once those formulas were “reapplied” to the structure and performance requirements. In a lot of cases, the increase would start with a new engine option then the airframe was altered to take advantage of that larger engine.

 

[Dan Thomas]

It was weighed after having the engine oil drained, on modern certified scales, properly leveled both side to side and fore and aft, and with fuel added-- by moi on a stepladder-- to the new tank until it exited the hose disconnected from the carburetor.

That isn't how unusable fuel is determined. Normally, one consults the POH or the Type Certificate Data Sheet for that figure, but the TCDS for the Luscombe 8 series doesn't give it. In any case, it's the fuel that will not leave the tank to get to to the engine in an attitude most critical for flight. So suppose you are in a steep climb attitude, or a steep descending attitude, not level at all. Depending on where in the tank the outlet or outlets are located, you might starve the engine of fuel in one or both of those attitudes with the amount of fuel you put into the tank. Two gallons? Per side? Don't know. Never looked at a Luscombe's plumbing. If there are outlets at both the front and rear of the tanks you should be fine. If there's only one, near the middle, you might not be. Hard to say.

Anyway, the TCDS has a lot of good info, especially the weights and arms for a lot of that stuff you had to weigh and measure. Could have saved a lot of work and gotten amore accurate result. Read it, thoroughly: https://rgl.faa.gov/Regulatory_and_...df538e5862586fc004b8ce4/$FILE/A-694_Rev27.pdf

 

[Huckster79]

Take off what ya can then reweigh…

I’m doing that now to my c140, couple more projects and off to the scales she goes

 

[Boundary Waters]

The TCDS for the Luscombe 8 series doesn't give it... In any case, it's the fuel that will not leave the tank to get to to the engine in an attitude most critical for flight. So suppose you are in a steep climb attitude, or a steep descending attitude, not level at all. Depending on where in the tank the outlet or outlets are located, you might starve the engine of fuel in one or both of those attitudes with the amount of fuel you put into the tank. Two gallons? Per side? Don't know. Never looked at a Luscombe's plumbing...

The 8A has a single 14 gallon fuel tank located just behind the pilot and passenger's heads (+40) suspended right over the baggage compartment (also +40). It is a flat oval shape (like the numeral "0" on its side. So it obviously has little space for fuel to hide in, from left to right. It has a narrow "V" shaped sump that is deep in front and non existent at the rear. The fuel delivery line comes off of the front of this sump, behind the pilot, under the left door, to the fuel shut off valve, and the gascolator before finding its way to the carburetor.

The system is gravity fed-- and so far gravity has never just quit working -- so there is no fuel pump. The fuel filler is centerline on the top of the fuselage near the front of the tank. Positive pressure in the tank is maintained by using the "flying cap" with a long (7.5 inch or so) curved vent that MUST be installed prior to flight and MUST face forward so ram air is directed INTO the tank. It even says "FORWARD" on one side so the smartest of idiots won't screw it up.

There is also a "ramp cap" that prevents water vapor from entering the fuel system. They get switched before and after flights.

In a perfect bureaucratic solution to a real world issue. The aircraft is placarded: "Full carburetor air heat required for takeoff and landing."

(From A-694) "The reason for this placard is that during takeoff acceleration and initial high angle-of-attack climb, the fuel flow may not be adequate for proper operation. Application of full carburetor heat in this case helps overcome the possible deficiency of fuel flow during takeoff. Carburetor ice is not a basic consideration in requiring this placard."

Carb heat works by decreasing the power setting on the engine, effectively "derating" it for takeoff. Which you can do manually, but the CAA was probably worried that some ingenious idiot would decide to takeoff at 55% power and not make it over the trees at the end of the runway. The lowest field I normally use is abot 600 feet AMSL and the highest about 1100. Rate of climb is a bunch of multiples of three... Six minutes (or seven some days) at sixty miles an hour to 3000 feet AGL at 1200-1260 pounds.

Even without ADS-B radar operators are not going to mistake me for an F-16 headed out to Snoopy West...

There is an edited copy of the TCDS that is carried on board the airplane-- paragraphs pertaining to other models and equipment not carried onboard were deleted. The result is not very long. From 16 pages-- for 10 models-- to less than 1/2 the page it shares with the W&B and performance numbers. It's important, but not detailed, and not up to date.

 

[Dan Thomas]

You have a C85. That carb heat placard applied to the 8a with the A65. You should have some STC paperwork that would either retain the carb heat placard or call for its removal. I don't know what difference carb heat would make to fuel flow other than reducing the power so you have a flatter climb attitude and therefore a larger fuel pressure head.

 

[Boundary Waters]

I don't know what difference carb heat would make to fuel flow other than reducing the power so you have a flatter climb attitude and therefore a larger fuel pressure head.

That is EXACTLY what it does. So does pulling the throttle back just a little bit...

You have a C85. That carb heat placard applied to the 8a with the A65. You should have some STC paperwork that would either retain the carb heat placard or call for its removal.

No, I have a Luscombe 8A with an A-65-8, hand prop, counter-clockwise tach. All the good stuff... None of the fancy stuff...

From Univair (configuration as built)

8 1937-1940 A-50 1130 lb., 113 blt., Fabric Wing, Fuse Tank, no electrics
8A 37-41 and 45- 51 A-65 1200 lb., 3449 blt., Fabric Wing, Fuse Tank, no electrics, begin at s/n 833
8A Special 1945-1951 A-65 1200 lb., 95 blt., Fabric Wing, Fuse Tank, no electrics
8A Sky Pal 1945-1951 A-65 1200 lb., 151 blt., Fabric Wing, Fuse Tank, no electrics
8B 1937-1940 Lyc. O-145B 1200 lb., 85 blt., Fabric Wing, Fuse tank, no electrics, '46 style panel, begin at s/n 1699
8C 1937-1940 A-75 1260 lb., 278 blt., Fabric Wing, Fuse Tank, no electrics, fuel injection, new panel, begin s/n 894
8D 37-40, '45- 51 A-75 1310 lb., 97 blt., Fabric Wing, Wing Tanks, no electrics, '46 style panel, begin at s/n 1807
8E Deluxe 1945-1951 C-85 1400 lbs., 911 blt., Metal Wing, Wing Tanks, elect system, long chrome stick, begin at s/n 4200, metal wings at s/n 3518
8E Special 1945-1951 C-85 1400 lbs., 127 blt., Metal Wing, Wing Tanks, electrical system, new panel
8F Deluxe 1945-1951 C-90 1400 lbs., 270 blt., Metal Wing, Wing Tanks, elect system, new panel, Silflex gear, begin at s/n 5920, 1948 Square Rudder & fin
8F Special 1945-1951 C-90 1400 lbs., 59 blt., Metal Wing, Wing Tanks, electrical system, new panel
T8F Trainer 1945-1951 C-90 1400 lbs., 73 blt., Metal Wing, Wing Tanks, electrical system, new panel
8F Sprayer 1945-1951 C-90 1400 lbs., 35 blt., Metal Wing, Wing Tanks, electrical system, new panel
Tempco 8F 1945-1951 C-90-12F 1400 lbs., 44 blt., Metal Wing, Wing Tanks, electrical system, new panel
Ft. Collins 8F 1956-1960 C-90-12F 1400 lbs., 80 blt., Metal Wing, Wing Tanks, electrical system, new panel

I have seen a copy of the Factory Letter that details what I consider to be a pointless conversion from 8A to 8D. It requires either the replacement of the fuselage tank with two wing tanks or a fuel pump, documenting that all of the parts in your engine conform to A-75 standards, modifying the carburetor, replacing the propeller, re-timing the engine, as well as some things that I may have forgotten.

After all of which you only gain 30 pounds of useful weight. At my weight I would gain the five most expensive pounds of payload since the Apollo Space Program AND lose performance in the trade.

I understand that there is also a Factory Letter to convert an 8A to an 8E which would add either 120 pounds of useful weight, OR an electrical system and the extra fuel you'd have to carry to have the same range as the unmodified 8A... That requires switching from an O-170 to an O-190, and installing wing tanks.

The majority owner considered both options briefly before deciding to restore the aircraft in its original configuration which my buy-in funded. Win-win.

I'm not saying those conversions are bad, I'm sure that some would people prefer an 8D or an 8E. But neither one is something that I would personally prefer. The 8A is a timeless classic.

 

[Boundary Waters]

Intermediate (between Grade A and glider cloth) fabric had a finer weave so it took less dope to seal. I would say ceconite would be heavier.

There is a Ceconite Instruction Manual over at Aircraft Spruce that has weights of different covering systems per square yard when completed per guidelines. A J-3 (178.5 sq ft wing area) was given as an example-- my 8A has 140 sq foot of wing area and a similar Clark Y derived airfoil. Ceconite was stated to weigh 2 pounds more per wing than Intermediate Cloth and 4 pound less per wing than Grade A Cotton.