Fuselage and Tailfeathers
I want to polish my unpainted airplane.
The original Luscombe annual checklist says to use steel
wool to clean the fuselage. Should I?
What is the difference in round versus Square tip Vertical
Stabilizers?
Engine |
CruiseSpeed (mph) |
T/O |
Land |
Gross Weight (lbs) |
A50 | 95 | 700 | 500 | 1130/1200 |
A65 Cont | 98 | 550 | 500 | 1200/1310 (grade A fabric) |
0-145 Lyc | 95 | 700 | 500 | 1200 |
C75 Cont | 100 | 550 | 500 | 1200/1310 (grade A fabric) |
C85 Cont | 110 | 650 | 625 | 1400 |
C90 Cont | 115 | 650 | 625 | 1400 (T8F GW restricted category @1470#GW, drop tested to 1710#) |
0200 Cont | 118 | 550 | 700 | 1400 |
0235 Lyc | 125 | 550 | 700 | 1400 |
0320 Lyc | 135 | 450 | 700 | 1400 |
The A65 was often converted to a C75. The conversion gives a Redline of 2600, cruise at 2450, and a lower TBO of (estimated) about 800hrs. (This is considered optimistic by CAS). The conversion needs new a prop, pistons, pins because HP increase comes from additional RPM, so prop pitch is lower. Aircraft flies about the same speed but climbs about 100FPM better.
A2: This is probably the most reasonable engine upgrade or solution to the growing lack of parts for the original C-85 engines. The first step is to get the airframe from 8A to 8E configuration per ATC 694 and service letter dated August 4, 1947 (approximate cost 1998 $5,000- CAS has paperwork and materials). Then convert the 8E/F configured airframe in accordance with an STC or field approval. Can be done today using a field approval with the STC data as its basis. Call CAS for details.
A3: There is an STC held by McKenzie Aviation to make this conversion, but is not available due to change in ownership.
A4: Cost of the kit and STC in 2000 dollars is about $5,000 less engine (many $$) and propeller ($1,900). Kit includes additional hard points for the firewall, engine mount, installation instructions, new cowling, baffles.
A5: Convert 8A to 8E/F configuration per ATC 694 and service letter dated August 4, 1947 (approximate cost 1998 $5,000- CAS has paperwork and can assist with materials to accomplish this modification).
A6: Mostly the engine installation, but there are some "marketing changes such as a better or worse interior installation or other cosmetics. See the chart of model comparisons on the CAS web pages (see A1). T-8F is same basic frame as the 8F, but tandem seating and a big rear bubble window over the rear seat.
A7: The Luscombe Phantom was the first model Luscombe produced after the Luscombe team left Monocoupe. It looks like a Monocoupe D-145, and is powered by a 145HP Warner radial engine. It is designated Model 1 and was built circa 1933-1941. Seven remain of 27 built, and 31 serial numbers were issued for production (4 were cannibalized to repair other units).
A8: The sedan was a four place utilitarian high wing Luscombe produced in the quantity of about 100 during 1948. It was powered by a 165 to 185 HP Continental engine and boasts a cruise of about 130 in opulent comfort.
A9: A single seat low wing (rag) prototype. It was destroyed in 1948 for tax purposes. The engineer, Misha Cantor, advised in 1998 that he had recently destroyed his drawings and files on the airplane also.
A10: Yes, the Luscombe 8G (1959). It was never certified, but the remainder of the prototype survives, hopefully to be returned and displayed in a museum.
A11: Goodyear 3" multiple disk brakes were used on very early 8 series airplanes. Shinn/Firestone drum brakes were used on many 8A-C airplanes. These are identified by the linings riveted into the wheel and the brake shoes which are bare steel attached to the axle. Models 8A-F had Cleveland mechanical drum brakes as an option. These had conventional linings on shoes and a drum much as is used in cars. The last brakes used in production were the Goodyear mechanical disk brakes which are about 11" in diameter. These worked best but were hard to adjust and often misunderstood by mechanics and owners. CAS stocks supplies for all of these brake types including springs, shoes, disks, wheels, keepers, etc. CAS has also designed a hydraulic kit including master cylinders, reservoir, lines, fittings, connectors, calipers, disks, and wheels sized to the airplane and tested extensively. CAS can install the kit for you with a one time 337. You must do the installation under CAS supervision, and we must complete a conformity inspection and return to service.
Q12. Can I add the right side brake pedals?
A12:. Yes. It takes a little less than a day's work to install; not complex just a lot of details. Since this is an area that gets little or no attention since the plane was built, you are going to fiddle around cleaning and inspecting and maybe doing a little painting, etc. You need to allow for that in planning the work.
CAS makes up a kit of parts to add them; the biggest cost item is the pedals themselves. They are fairly complex having a lot of small parts to set in a fixture and weld. The kit also includes new metal pulleys for the cables to replace the fiber ones per the original design prints. We think this is because of the extra stress from having a second set of pedals. Install of metal pulleys is also suggested to improve a normal one place brake installation. The kit also includes some cables to splice to the existing brake cable. It's a good time to inspect what you have and replace it if its worn or weak. The splice is done via a nicopress fitting. The kit includes a small drawing and refrences from TC data sheet to do the installation. This is issued for a specific serial #, so you need to supply that when ordering the kit.
The kit is about $450.00; they are usually in stock, or can be assembled within 30 days of ordering. These days it really requires a 337 major repair or alteration form, and most mechanics are going to want to have an AI look over the work and sign it off. In the old days it would have been done with a log book entry, but times have changed... For now, the add on is original factory for any of the mechanical brake applications.
A.13: Jack the airplane at the inboard section of the axle, behind the wheel mounting and below the leg.
A14: The Silflex gear is a later innovation after SN 4400, heavier, has a larger cross section, and has no guide wires. Is this a desirable feature? Generally yes. The track is a few inches wider, and the landings a bit smoother. However, the conventional 08311 standard gear with the ski strut option (18322) installed to replace the landing wires is nearly equivalent structurally. It is also lighter, and will shear without fuselage damage. An accident in a silflex gear airplane usually rips out the gearbox first because the gear legs are stronger than the airplane. The opposite is true with the earlier Luscombe gear.
A15: See A14, it's a simple change, takes a couple of hours to do, and is a factory option so paperwork and FAA approval is streamlined. Its design makes the gear more resistant to side loads.
A16: No, No, No! The gear legs are heat treated at the factory, and any heating you do will weaken them and will likely lead to a failure on landing (i.e. you will wreck your airplane). There is an old service letter, and a service recommendation #5, both of which offer an alignment process and specifications to follow. Luscombe Association newsletter #55 may help. The information on the specific hardness is in there. It also states that AC 43:13A requires the re-heat treat, to be legal. On page 3 it goes further to tell the numbers. 170,000-180,000 UTS and Rockwell 38-42 C scale.
A17: Mobilube 90 is equivalent to 30 wt engine oil-detergent or non detergent is immaterial. The oil is not used to absorb landing shock, but rather to keep the spring from rebounding quickly as the oil passes through a metering orifice.
A18: There are several options:
a. The "comfort" seat features Temperfoam, manufactured by
Hi-Tech Foams, Inc. This special foam is a three-layer foam, each layer of a
different density. The foam will conform to the pilot's/passenger's bottom,
then will "spring back" for the next "bottom" which "sits on it". The seat
back provided is also made of aluminum, and can be tilted forward for easy
access to the baggage compartment. Contact CAS for details (Kit with
upholstery is about $1050). Your seating range will extend to 8-10 hours.
b. Replace the Factory sling seat with Cessna C150 seats. Cessna 150
seats are more comfortable than original Luscombe seats, and ride on
adjustable rails (of course the range of adjustment is more limited than in
a Cessna 150). An advantage is that they adjust independently of each other,
allowing for a short pilot and tall passenger or vice versa. A disadvantage
is a recurring AD that comes with the seat tracks, (inspection at annual time) and replacement as needed of
rollers and washers. The Luscombe Association and CAS has drawings and samples of
previously approved 337 paper work that you can use to develop your own
paper work from and get your own FAA field approval.
c. The "Jack Norris" seat is a "bucket" type seat that positions your
body in a slight recline. Some say there is more leg room. Jack sells a set
of plans for making the seat. If you have basic wood working skills you can
do this yourself. The down side is that the seat must be completely removed
to get to the baggage area.
A19: See A18. Also with some modifications the floor can be lowered about .75 of an inch. This is said to help people up to 6 feet tall, but taller people won't get much relief.
A20: The Panel, door jams, and generally the stripes were a flat matte color with little reflectivity; Dark blue or Burgundy were the two factory color choices.
A21: The standard fuselage tank is located behind the passengers and holds 14 gallons. The metal wing tanks hold 11.5 each (early rag wing tanks), or 12.5 gallons each. The less common pliocell tanks hold 15 gallons each (identified by the bulkhead for the Pliocell tank at the filler cap). An 8A can have wing tanks added, but the fuselage tank is generally removed. IF the wing tank is installed, it should be used for all take off and landing operations, and the fuselage tank should be used in level flight or cruise. The fuselage tank has a lesser fuel pressure head and can cause starvation to the engine during climb. You may add 4.5 gallon "Timm tanks" to the rag wing installation (with fuselage tank). These auxiliary tanks drain into the fuselage tank. See ATC 694 type data sheet for more details.
A.22: This is a common pliocell problem if the tanks are not kept full in storage. The solution is to remove the tank and replace it. CAS has a vender that "rebuilds" these tanks using a new rubber bladder of thicker material and new attachments vulcanized into the units. We must provide a different fuel finger screen arrangement for the new bladder, but the fuel cap and gauge areas remain the same. We have installed several of these "rebuilt" (all new parts) with great success. The Goodyear pliocell tanks were not a good product and created problems as soon as they came into service. Replacement cost is approximately $1200 per side.
Conversion to metal tanks is also an option at about the same price but with a loss of about 4 gallons useable capacity, but few service problems and longer life. This does require a removal of some minor aluminum sheel in the pliocell bay- not a big deal.
A23: Construction is completely different. The fabric wing is about 50 pounds lighter and uses conventional spars ribs and internal bracing structures. The metal wing is fully monocoque in construction with formers to shape the wing, but the load is carried by the skin and spars as a semi-monococque unit. Metal wings can have flaps.
A24: The 8A was produced with both fabric and metal covered wings. The post 1946 models were covered with .016 or .020 alum. skin. Later models had only .020 skins.
A25: Correctly. Wings should maintain level flight with minimal aileron
input and rudder input that can be trimmed out later. One degree, 45 minutes
perpendicular to the strut attach fitting area of the wing is the correct
wash out. The wings should have 1 degree of dihedral, which is determined by
the length of the lift strut. How to adjust:
Base line is to use an electric protractor at the wing root ribs. Call this
zero. At the rib between the front and rear strut, the washout should be 1
degree 45 minutes for ATC specification. This may have been reduced to as
little as 45 minutes on some airplanes which were very straight, they then
go faster..... When you get an airplane that stalls in a docile manner, and
can sustain a "falling leaf" maneuver with only rudder inputs you have done
a fair job. After getting the "book spec" you desire, trim the wings level
with a reduction in washout (lengthening rear strut) on the wing which is
rolling UP. Be careful to NOT turn the rear strut forks more than a half
turn between test flights. A full turn, or a turn and a half is enough to
nearly overpower the aileron control inputs. Fly safe. Have an AP check your
work. Metal wings are not adjustable except during construction. Trim tabs
on ailerons and the tip spurs can be used to rig an airplane to overcome
some jigged mistakes.
The wings are in good shape with only superficial corrosion, however, the outboard skin panels of the leading edge are very rough. I would like to replace these skins, but I do not see how I can buck these rivets with the limited access available. Is this a commonly performed repair, and if so, is there any specific tool (bucking bar) or technique necessary?
A26: This is common, but difficult to repair without opening the wing at the
rear spar area. Remove wing tips, providing access to outer wing panel.
Remove leading edge and reinstall. Originally the front spar was bucked with
the rear spar rivet line still open. This is still the best way, and would
require removing about 50 more rivets (and the tip). We also suggest that
you install the wing inspection kit that allows routine inspection
of the internal wing as required for annuals and by the FARs.
Upon stripping the paint from the wings I noticed slight creases on both wings running above the wing tank area. Can you tell me what damage occurs when the wing is over stressed? How can I verify if damage is present?
A27: The kind of damage you describe is typical of a ground loop incident
where there is a torsional load on the wing transmitted through the wing
skins about mid aileron, and from the tip to the root of each spar to
determine if any "SET" has taken place (not likely). Many Luscombes have
similar deformities but fly on just fine. Replacing the skins should be done
in a jig but can be carefully done on saw horses with an electronic
protractor. Jigging details are available for about $160. Cost to rebuild depends
on shop skill and experience. We estimate about $3500-4500 per wing to repair
such damage and recondition a wing.
A28: Flaps were available as an option on the 8E and 8F, and on the T8F. They are very effective, but add about 30 lbs to the weight of the airplane. They can be added to an existing set of wings with some work. CAS estimates about 60 man hours, and the cost of parts (used and new) at about $3500-3800. They are available from CAS with an order and substantial deposit.
A29: Refer to ATC694 and service letter. It is required to reduce the power on an A-65 or -75 when using a fuselage tank. With low fuel, (1/2 tank or less) and a cool day, when the engine is making lots of power and you are in a steep(er) climb angle it is possible to get the engine fuel inlet ABOVE the fuel tank outlet, which causes fuel flow to cease (and the engine quits). Carb heat on was a simple and cheap fix to this as it reduced the power the engine could make and thus reduced the deck angle. It is also why wing tanks are required on higher HP engine conversions, and why wing tanks are strongly recommended for all Luscombes in general.
A30: This carb "automatically" leans due to the methods employed internally. Saving 10% of your fuel in a 4GPH aircraft could be very expensive when you start burning metal parts. The mixture control on the Stromberg carburetors does not work in the same fashion that more recent mixture controls work, i.e. later ones completely cut off fuel flow at idle in the mixture full lean position via a mechanical equivalent to a shut off valve. The Stromberg carbs are fitted with a method of putting slight vacuum on top of the float bowl in the carb which has the effect of reducing the fuel air ratio (leaning) when the engine is running at cruise power. It has minimal effect at idle and is not intended to shut down the engine. This back suction mixture control is not highly predictable and should not be used without an EGT.
The concept of never leaning below 5000 (or 6000) feet is a corruption of the intent of the comment and generally applicable to the later Marvel Schebler carbs. The original instruction was to always lean above 5000 feet as it was desirable to adjust the mixture to compensate for the otherwise overly rich condition which existed in the thinner air aloft. It is perfectly safe and prudent to lean the engine once cruise power is established, even at sea level. Without an exhaust gas temperature gauge, which is not a common instrument on a Luscombe, the usual procedure is to lean until the engine starts rough and loses RPM and then enrich just enough to smooth it out.
Due to the temperature irregularities in leaning small Continental engines, the use of an EGT gauge is highly recommended.
A31: The Stromberg carb has an 'economizer valve' as they called it. It does indeed work at all altitudes, but it is not a full-cutoff mixture control.
Proper procedure is:
A32: CAS has a good repair facility for those nearby and can generally turn them for $300-500 depending on your needs and desires. A basic replacement of the needle and gaskets can be done for about $225 by J & G Carburetor, Inc., 2735 Brookfield, Dallas, TX 75235. 214 350-2032 as recommended by some of the Mail list members.
A33. Certified 60A alternators are generally available for about $900. Also a 20A generator is available. A third option is a light weight field approved alternator installation that CAS can provide with 337 approval. CAS can probably track this down for you.
A34: The data plate on my A-65 is unreadable except for the stamped serial number. Every time I get a new IA, I have to get past his objections. I decided it would be a good idea to get a new plate. The drill is to talk to the FAA first, Get a letter from them and send a copy to TCM with $25. TCM will then sell you a new one. I called TCM first to verify that the serial number was valid and was told there were too many digits, and leaving off the first or last digit didn't produce a valid number. At the Columbia Fly-in, I looked at other A-65's and all had equally unreadable data plates, with the same number of digits I have. A second call to TCM with an explanation got me in touch with a fellow who had been there a good while. The net result is that I know that 3848568 is really 38485-6-8, which apparently translates to A-65-8 made in 1946 whose serial number is 38485. (He also told me the engine was sold from Continental to Luscombe in early 1947.) Thanks to Bill Archibald.
A35: The airplane was certified with NO markings, just numbers limits specified in the operator's handbook so technically the arcs and ranges on gauges and instruments cannot be required. They are, however, a good idea.
Airspeed Limits For All 8 series Airspeeds (Land Plane)
Stall | 48 mph |
Maneuvering speed (not necessarily marked) | 85 mph |
Normal operating speed (green arc) | 48-115 mph |
Caution speeds- smooth air only, (yellow arc) | 116-144 mph |
Redline (radial red line) | 145 mph |
Flap speeds (white arc) | 40-90 mph |
Luscombe Owner's Manual Limits
Continental A65 -8A Engine Gauges- (65HP) |
Oil Pressure Operating Range
Minimum | 25 psi |
Normal | 30-40psi |
Maximum | 48 psi |
Red radial line | 10 psi |
Yellow Arc | 11 to 24 psi |
Green Arc | 25 psi to 48 psi |
Red radial line | 48 psi |
Oil Temperature Operating Range
Normal (green arc) | 120-220 F |
Caution (yellow arc) | 40-120 F |
Maximum (red radial line) | 220 F |
RPM Limits
Idle | 550 rpm |
Cruise | 2150 rpm |
Green Arc | 1800 to 2349 rpm |
Max (red radial line) | 2350 rpm |
Continental Motors Limits for A 65 (Not Specific to Luscombe)
Oil Pressure Operating Range
Idle Minimum | 10 psi |
Normal | 30-40psi |
Maximum | 48 psi |
Oil Temperature for take-off | 90 degrees oil temp minimum |
Continental C-85- 8E Engine Gauges- (85HP) |
Oil Pressure Operating Range
Minimum | 25 psi |
Normal | 30-40 psi |
Max | 48 psi |
Red Radial Line | 10 psi |
Yellow Arc | 11 to 24 psi |
Green Arc | 25 psi to 48 psi |
Red Radial Line | 48 psi |
Oil Temperature Operating Range
Caution (yellow arc) | 40-120 F |
Normal (green arc) | 120-220 F |
Max (red radial line) | 220 F |
RPM Limits
Idle | 550 rpm |
Cruise | 2350 rpm |
Green Arc | 1800 to 2574 rpm |
Max (red radial line) | 2575 rpm |
Continental Motors Limits for C-85 (Not Luscombe)
Oil Pressure Operating Range
Idle minimum | 10 psi |
Normal | 30-60 psi |
Max | 48 psi |
Oil temp minimum for take-off | 75 degrees |
Continental C-90, 8F Engine Gauges |
Oil Pressure Operating Range
Minimum | 25 psi |
Normal | 30-35 psi |
Max | 48 psi |
Red Radial Line | 10 psi |
Yellow Arc | 11 to 24 psi |
Green Arc | 25 psi to 48 psi |
Red Radial Line | 48 psi |
Oil Temperature Operating Range
Caution (yellow arc) | 40-120 F |
Normal (green arc) | 120-225 F |
Max (red radial line) | 225 F |
RPM Limits
Idle | 550 rpm |
Cruise | 2300 rpm |
Max (red radial line) | 2625 rpm |
Green Arc | 1800 to 2465 rpm |
Yellow Arc | 2466 to 2624 rpm |
Continental Motors limits for C-90 (not Luscombe)
Oil Pressure Operating Range
Idle minimum | 10 psi |
Normal | 30-60 psi |
Max | 48 psi |
RPM Limits
Max for T.O. (5 min.) | 2625 rpm |
Oil temp minimum for take-off | 75 degrees |
I have a Flowtorp 72-48, and I'm only getting 200-300 fpm at gross and it's not summer yet. Cruise is ok at 100-105mph.
A36: A 72-44 or 72-46 will improve the climb situation by 3-400 or 200fpm
respectively. See if you are in the ATC specified RPM range now, and be sure
to check the tack as well as VSI (both are known for inaccuracy). Your numbers could be in error, or you
could have a weak engine, too. Cruise will drop 3-5 mph per inch of less
prop screw. So you will climb well at 72-44 but will not go better than 90
or so.
A.37: A cruise prop should come up about 50 to 100 rpm shy of redline at level flight if the engine is producing proper power. A climb prop should come up to about redline or redline +50 rpm in level flight. Sensenich tends to UNDER pitch slightly so I would check the tach calibration and engine output before making a final call. Tachs tend to indicate low after a few years due to internal friction and poor lubrication.
A38: Do not wrap your fingers around the blade behind the prop. Swing your closest inboard leg out under the prop and pull toward you to keep you out of the propeller arc. NEVER lean into the propeller arc and start with the compressions of the propeller at the 10 o'clock position (from the front) Service the mags or buy new ones. GET instructions from someone who knows how to do this start sequence and handle the airplane. SAFETY first. See hand propping guide.
A39: Seek mental help. There are many methods and products on the market, all of which have good and bad sides. CAS has special cleaners and polish bars for use on low speed buffers. You will need to use a polishing compound that has a light abrasive in it. And then wax the surface after your polish out the corrosion, oxidation and discoloration. You may also find that its more work than you can do by hand, you may want to borrow, buy or rent an electric polisher with several wool pads. Keep the pads away from dirt and course grit as it will scratch things up. CAS also has other cleaners they have tested from time to time. Call for quotes and availability. Nuvite is one of the best.
A40: No. Never do this. Maybe Luscombe wanted to sell some replacement fuselages a few years after you would do this. The steel will get imbedded into the Aluminum skins and you will get a lot of corrosion. If you need an abrasive, use scotch brite pads. Also do not use any abrasive made of aluminum oxide (popular in sand papers) as it in effect the seeds of corrosion which it will imbed in your airplane.
A41: The round tips were on models produced from 1938 through 1947. The square topped tips produced after 1947. However, the exception is that factory supplied replacements were square tips, and they could also be swapped with other planes, so one tip versus the other is not a reliable way to tell the vintage of the fuselage.
A42: The Luscombe Association publishes a newsletter. You can subscribe through CAS.
A43: CAS has a large stock and variety of Luscombe support and parts. These are not current production airplanes but antiques that are still doing daily training and business. Luscombe parts are generally available. The support is not as cheap as your Pinto car, nor are the parts and technical assistance as expensive as Boeing, Beech, or even Cessna. You get a fair price for good parts that are most often new production FAA approved, certified, PMA parts.
A44: Get a copy of the Luscombe annual inspection checklist, add emphasis to the AD areas and the 7-10 year "heavy" checklist. Call CAS for details or consultation.
A45: No. Most of the stories you hear are from pilots who are less proficient than they wish to have you believe. The airplane is very responsive and light on the controls. To some this means that the airplane is unmanageable. It is NOT a Cessna 152, a Cub or Citabria and does require that you learn to understand and use ALL THREE axis controls independently and in concert with one another to fly well.
A46: It was SL8 that was recently revised, and "L8" seems a logical contraction.
A.47: Luscombe List Members recommend The Milepost to anyone who wants to fly to Alaska. You can get this publication at your local Barnes and Noble bookstore or at The MILEPOST
A48. It's Not Easy. Hire an accountant and attorney. Spend $3-9,000. Incorporate, file with IRS, hope they see why you are a not for profit educational and historical preservation society. The IRS has forms. standards and requirements to meet.