I'm going to start using revision letters on this site. I will use colored fonts to show you what has been added, deleted or changed. Then when I make another revision I will convert all the colored fonts to black and make the new data in color. You should be able to look at the revision letter and know if I have made some changes. I hope this is not too confusing. And I hope it will work!!!

A is DATED 1-17-06. B is dated 1-25-06 C is dated 3/3/06 D was updated on 3/18/06

B. Missing

C. Added shipping data.

D. Added spinner information in blue fonts. 3-08-06

E. Service Bulletin SB2000_001A Link Added 03-18-06

Photos will now display properly

Web sites last modification March 25, 2006 ; Added note about the Swift "Aeromatic Expert". Mar 30, 06.

There is an Expert on the Swift club web site that knows all about Aeromatic and "Beech Roby" propellers. This man exposes his gross ignorance about both propellers. He call the Aeromatic extremely expensive and needs to be overhauled every 200 hours at a cost of $3500. He says they are slow. On and on his diatribe goes. So if you read and heed his recommendations then I don't want to sell you and Aeromatic for a Swift airplane. It is also clear that this man doesn't understand the aeromatic, doesn't know how to set one up and doesn't know how to use it. He says they are not efficient. He must have determined that by his hearsay expertise. Of course he doesn't quote any efficiency numbers and most likely doesn't know what efficiency one should expect from a propeller. I have heard of this Joker before and I've been told about him from some of my customers.

So, let's see. The Aeromatic has been certified and used on many airplanes since 1946. I have overhauled several that were made in the late 1940's and were found to be in airworthy condition. The Aeromatic has no life limit. The Aeromatic has only 3 AD notes against it in it's 61 year history. The average efficiency of the Aeromatic is around 83% at. That is the kind of numbers you get on Hartzells, McCauly and Hamilton Standards that are used in the 1800 to 2800 rpm range. Slow turning propellers like those used on turboprop engines can realize efficiencies up 90% and perhaps more. But those props are turning in the 1200 to 1400 rpm range. No propeller will display the same efficiency under all conditions of takeoff, climb and cruise.

Efficiency? Here is a typical efficiency curve on a Lycoming 0-435 engine powered airplane. At 40 mph, 43%; at 60 mph, 57%; at 80 mph, 62%; at 100 mph, 74%, at 120 mph 78%, at 140 mph, 81%, at 160 mph, 83%. Those number are at 2300 rpm. Some others, C-170 with C-145 at 2700 rpm and 125 mph - 81% efficient. Stinson L-5 w 0-435 - NACA Report #640, 185hp @ 2550 rpm - max level flight speec of 129 mph - efficiency is 82.2% this is at sealevel. Another one, Stinson XL-13 - with X0-425-5 engine - 240 hp @ 1995 rpm - at 150 mph efficiency is 82.5%.

MAYBE I WILL ADD MORE OF THIS LATER

Today is 23 April 06. As a matter of fact I am going to add more soon as I can get my ducks in a row. This joker or one or more of his disciples has creamed a deal I had going with A/C Spruce and a potential deal with Liberty Aircraft for their XL-2 airplane. If I

can get some evidence that will stand up in a court of law I think I will call a pow-wow in the presence of a judge. The Swift web site has provided me with a lot of his diatribe in

writing under his column titled something like this "Mondy The Answer Man".

In my next update of this site I am going to quote a string of his diatribe and add my comments.

So, Stand by for NEWS!

TARVER PROPELLERS, LLC

1500 Rio Vista Dr. Hangar C-4

Fallon, NV (FLX)

775-423-0378

SHIPPING INFORMATION

I am having reasonable success using 260# double wall cardboard boxes for the F200 propeller. I am charging only $35 for crating plus freight to ship in this box. Most companies charge half that much for handling items weighing only a few pounds.

I am not yet comfortable with cardboard for the model 220 propeller. I am charging $100 deposit on the wood box used to ship the model 220. I will refund the $100 if you will

return the empty box prepaid.

I am trying another method to outsmart the spambastards. So you will have to assemble my e-mail address. Also I am in the process of changing my e-mail

address as you will see below.

Old address n77kt(at)oasisol.(leave this out)com

New address is n77kt(upper case 2)hipster.(leave this out)net

I will still keep both addresses until I am pretty sure most everyone is using the new one.

From now on, I will require $1000.00 up front on all

orders for propellers. That includes overhaul of your

propeller.

My policy has been to not require money until I have a deliverable propeller ready for shipment. That will no longer be the case. It is a lot of work and expense to make a

propeller. I can't afford to turn out propellers for people who don't want them. This

problem also makes other customers wait longer for their propeller. They get teed off and I can't blame them. I've tried to keep my business on a helpful footing for the

customer. I didn't want to be a hard nose business organization. But I am learning the hard way. It doesn't seem to pay to be a nice guy.

SPINNERS BY AIRCRAFT SPRUCE

As many of you know I have been negotiating with the Irwins, Jim at A/C Spruce and his brother at ACS, At first they seemed to be interested in making a spinner for the

Aeromatic propeller. Jim said he would make it available in his regular catalog. So he put me in touch with his brother John of ACS in Havasu, Az. I gave him a hub with an original spinner attached in October 2005. I checked a few weeks ago on progress and they hadn't done anything at that time. Today, 8 March 06 I got a call from a nice little

lady from A/C Spruce in Corona saying that they were not interested in making spinners for the Aeromatic. I didn't hear from Jim or John and the little lady didn't have any

details. I've been trying to get John on the phone to no avail. However a little lady at ACS mentioned something about tooling cost and suggested that if I pay for the tooling then perhaps they would make the spinners. I can't talk to John so I don't know what the cost would be. If and when I learn anything more about this issue I will post it on this

web site.

I am not interested in getting into the spinner business. So, if anyone out there is interested or knows anyone that would be interested have them contact me and I will

make the details available to them.

I just checked the TCDS's for the Bellanca and Stinson and see no requirement for a spinner on either of them. I have a Bellanca Cruisair with a Lycoming 180 hp that I plant

to put an Aeromatic on. Right now the propeller is a Hartzell CS and the engine really runs cool, I've never had an oil or cyl temp problem. I will instrument to plane while still in present configuration and take data on temp etc. After I put the Aeromatic on it I shall

repeat the testing and take data to see what may change. There may be some airplanes out there that need a spinner for cooling but I don't know of them.

ALERT - ALERT - ALERT

AEROMATIC MODEL F200 ON 0-320 AND 0-360 LYCOMING ENGINES

BACKGROUND: I spoke with Univair, previous owner of the Aeromatic propeller, concerning the use of the F200 on the above named engines. In 1963 Univair pursued the certification of the F200 on a Beech 23 equipped with an 0-320-D2B. This is a 160hp

engine. The tests that Univair conducted proved that this particular engine/propeller/airframe combination is not compatible. They found broken lag screws in the blades. Their evaluation of this led them to stop pursuing and STC for this combination. This alert does not apply to these propellers used on the smaller 4-cylinder engines. By looking at the list of airplanes listed below you will notice that the propeller has been used on most of the 4-cylinder Continentals and Lycomings from the 0-170 through the 0-290.

Therefore is is Tarver Propellers, LLC's decision to warn all potential users of the F200 on any model of Lycoming 0-320 and 0-360 engines of the potential dangers of blade separation due the vibration. Tarver Propellers, LLC is urging that any user of this propeller/engine combination have the blades removed and inspect for broken lag screws before further flight..

There are three steps in performing this action. 1. Disassembling (removing the blades), 2. Inspection for broken screws and 3. Re-assembling the propeller.

DISCUSSION: If the owner/operator of this propeller/engine combination, used on certified airplanes, wants to perform step 1 then of course after he removes the blades, the propeller becomes unairworthy until they are reinstalled by a certified propeller repair station. This possible option can save the owner/operator some of the cost of this action.

If the owner/operator of this propeller/engine combination is used on an experimental airplane then he has different options for this work.

The following description is included here in order to give users an idea as to how much effort is involved. The hub does not need to be disassembled. The blades are removed as follows:

1. Remove the safety wire and the lock pin screw located on the bottom of the counterweight arm.

2. Loosen the counterweight arm clamp bolt, not the bolt that mounts the counterweights. This removes the clamping action upon the blade.

3. Unscrew the blade from the hub. The blade is screwed into the hub flange with right hand threads.

4, Check for broken lag screws by applying 150 inch pounds of torque.

Note: The final torque used to secure the lag screws is 150 inch pounds.

NOTE: The Aeromatic F200 prop has been FAA approved for 2800rpm at 180hp. However it is unknown by Tarver Propellers, LLC how many field approvals have been issued nor do we know any operational history of such. I have a letter written in 1963 by the owner of a Tri-Pacer 150 on floats that installed and certified the Aeromatic on his

plane. The letter indicates that the owner was very happy with the performance. I do not know any more about it.

It is my intention to install a F200 on my 0-360 powered Bellance and do some testing. Fallon airport is 3960 msl. I will not be able to generate 180 hp. But I may be able to generate 150 hp (equivelant to the 0-320) for test purposes. Perhaps someone can suggest a small inexpensive super/turbo charger that will normalize this engine to sea level pressure.

I am obligated to notify the FAA of this action and it will perhaps be issued as a service bulletin.

If anyone reading this alert has any experience with the above propeller/engine combination I would greatly appreciate your comments. Send them letter or e-mail, both of which is listed above.

ALSO READ SERVICE BULLETIN 2000-001A BELOW

GENTLEMEN When you telephone me, PLEASE BE MORE CLEAR WITH YOUR NAME AND PHONE NUMBERS. I am unable to understand at lease half of all messages left on my answer machine. My ears have had to cope with over 2,484,000,000 explosions of 80 & 100 & 115 proof gasoline and over 3 years copying Morse code through those old head-cans (before the days of padded headsets), not to mention all those twin 5" guns blasting away above my quarters on a tin can (that's a Destroyer) during the Korean war. I can still hear just about everything but my ability to discriminate between good data and bad data has pretty much gone south. I am very reliable about returning calls. So if I don't call you back it is because I didn't get your phone number.

I ask you please, use phonetics to spell your name and give the numbers as though you were talking to ATC, you know, fi-yive, niner, fo-wer, etc.

(well, maybe you don't have to go quite that far)

THANKS

I AM CERTIFIED TO MANUFACTURE NEW AEROMATIC BLADES

At the present time I am ramping up for production. I have several hundred used F200 hubs. I have only about six or eight 220 hubs. These hubs will be NDT'd for damage, they will be inspected to the drawing. There will be no such thing as oversize or

undersize parts in these Aeromatic propellers. Therefore the propellers will be virtually new.

NOTE: There are a few propeller experts scattered around this planet that will tell you that the Aeromatic is a piece of _ _ _ _. These props are supposed to be inefficient, high maintenance and don't work. If you believe them then I do not want to sell you one of these propellers. But just for the record, these props have no life limit in calendar time nor TIS. If they are taken care of properly I reckon they will last a long long long - long, long long time. (Harrison Ford). I have overhauled several Aeromatic props that were made in 1946 - 1948, They were in airworthy condition. I have the original data that Koppers originated on these props. I have many efficiency curves on various models and they top out about 83%. I understand that there is one manufacturer that is advertising that their props are now 85% efficient, OK. If you have laboratory conditions you may be able to see 2% difference.

I have approval to make blades that range from 68 to 78 inches diameter used on the F200 hub and from 78 to 93 inches diameter for the model 220 hub. The F200 fits a flange shaft engine and is FAA approved up to 180 hp at 2800 rpm. The model 220 fits a 20 spline shaft and is approved for up to 260 hp.

These propellers were certified on more than 70 different models of airplanes. I will be putting a F200 on my 0-360 powered Bellanca 14-13 before long. I want to run hell out of it to see how well it works and holds up. If it does well on that 4-banger it ought to work on just about anything.

PRICES. When Univair had the business they were able to buy the laminated block of wood, from which you can make two blades, for $65 each. I am paying $481 each. The plastic coating material cost them only a few dollars per propeller. The material was cellulose nitrate, same as photograph film up until about 1950. The ecology wackos considers this material a bomb. It is only made in other countries any more and the price is out of sight. All the costs have escalated considerably. If you want clear finish blades I will try to hold the price of the F200 to $4000 and the 220 to $5000. If you want composite blades the price is $4250 and $ 5250 respectively. All blades will be composite coated. You can have them painted black, white or maybe clear finish. I say maybe on the clear because it is more difficult.

BLADES. F200 paint finished blades are $3000 a pair, composite finish w/paint is $3300 a pair. 220 paint finished blades are $3200 a pair, composite finish are $3500 a pair.

These prices are my best estimate right now. I will adjust the prices after I gain some experience in production. These prices are subject to change without notice.

It will be some time before I will be approved to make hubs. But if you have you own 220 hub I can overhaul it and install new blades for an estimated price of $4550 plus parts you may need and assuming your hub is not beat all to _ _ _ _.

Below are photos of props and blades that I plan to make available. The two bare blades on the left in are under construction. They just came out of the profiler and are ready for hand finishing. Notice that the blade is a pusher. It will have a mate and it will be 58" long. The black prop is a factory overhauled and certified for use on 0-235 or 0-290 engines on Piper airplanes. It is 74" diameter and has the original cellulose covering. It is for sale, see below. It is a very good propeller. The white propeller are new production. They are wood covered with fiberglass. It is a 72" propeller.

I have FAA approval to finish certified blades with fiberglass. But if a customer wants a clear varnish over wood finish I will make it for him.

The white propeller does not have certified blades. The reason being that they are not made from a sacred FAA blessed wood block. However the block of wood is identical to the certified block, it was just made before I got FAA blessing. Though I will make blades/props for the experimental market they will be identical to certified props.

The paint I am using is acrylic enamel either Dupont or NAPA CrossFire automotive finish. Field repair of finish will be practical regardless of the kind of coating and finish.

CRATING AND SHIPPING IS EXTRA COST, ALL PRICES ARE FOB FALLON, NV

(Click on the images for a larger view)

THE AEROMATIC IS ELIGIBLE FOR USE ON THE FOLLOWING AIRPLANES

Aeronca 7ac, 11ac, 11cc, s7ac, s11ac ---- Bellanca 14-13, 14-19 ---- Cessna 120/140, 170 ---- Commonwealth 185 ---- Ercoupe 415C, CD, E, g ---- Goodyear GAJ-2, -2B

Jamieson J-1 ---- Meyers MAC-125C ---- Monocoupe 90AF-100 ---- Piper J-3C, J-5C, PA-11, 12, 14, 16, 18, 19, 20, 22 ---- Swift GC-1A, 1B ---- Stinson 108, -1, -2, -3

Temco TE-1A ---- Aero Design L-3805 ---- Cessna Airmaster 145, 165 ---- Fairchild 24W, 24R ---- Grumman G-44, A ---- Johnson 185 ---- Monocoupe CW ---- Navion 185, 205, 260

Stinson L-5 ---- Aeronautica Macchi MB-308, 320 ---- Auster Autrcrat J5 ---- Auster MK V ---- Desford Trainer ---- Fokker F-25, S-11 ---- Karhu 48 ---- L'Aronautique S-90

Lark KZ-VII ---- Nord 1200 ---- Piaggio P-136 ---- Pilatus P-4 ---- SAAB 91 ---- Iberavia I-11 ---- Culver LCA, LFA and others.

This propeller is headed to Santiago Chile where it will be fitted to a Cessna 140 (C-85)

NOTICE; I am not accepting repair work until further notice

Kent Tarver 775 423 0378

Aeromatic Automatic Variable Pitch

This site is continuously under construction more or less.

What is an Aeromatic Propeller?

The Aeromatic propeller is a fully variable pitch propeller that is virtually equivalent to a constant speed propeller. But it is not quite the same thing. The typical constant speed (CS) propeller for a Lyc 0-320 will weight about 54 pounds, add to that the weight of a governor and the cockpit control, you are pushing 60#. In addition to that, the engine has to have a hollow shaft in order to feed the oil to the hub.

The Aeromatic prop needs no governor, cockpit control nor a hollow crankshaft. It is entirely controlled by dynamic forces, centrifugal forces, air loads etc. The typical weight of the Aeromatic is about 30 to 34#. That weight varies somewhat depending on which configuration of the propeller you have. It will allow your engine to develop 100% horse power for takeoff, climb and cruise. Typically when you apply full throttle for takeoff you engine will rev up to about 50 rpm less than red line. After you have reached flying and or climb speed your engine will be turning red line rpm. After you reach cruise altitude and level off and gain speed, the propeller will increase pitch as you gain airspeed. Consequently you are now in cruise mode with more pitch much like a constant speed prop. This is not a two speed prop, it modulates itself based on the speed of the airplane and other dynamic forces. And it is not going to cost as much as a constant speed prop. These propellers were certified on most of the production airplanes during the big airplane boom right after WW II. Pipers, Stinsons, Ercoupes, T-crafts, Bellancas, Swifts, Aeroncas, Cessnas, Meyers, Monocoupes, Fairchilds, Grumman Widgeon, Johnson Rocket, Ryan Navions and more plus some foreign airplanes.

These props will be especially useful on many home built airplanes in the range of 40 HP or less up through some 260 HP engines. There are two basic designs, one for flange shaft engines and one for 20 spline shaft engines. The flange propeller is a potential propeller for some 30,000 C-172 airplanes. The other spline propeller fits many Warners, Rangers and other 20 spline shaft engines.

A Frequently Asked Question: How do you set up an Aeromatic prop?

This answer explains what you would typically do assuming your prop has been set up for your specific airplane/engine combination.

Technicalities: The Aeromatic F200 has 4 angles to be set. These angles vary across the spectrum of airplanes. These angles are; Phase angle, Counterweight arm angle, Low pitch angle and High pitch angle. The high pitch angle is fixed and can't be changed because it is a function of design. These angles are set at the factory. In the field the installer may or may not have to change the low pitch angle. There is another adjustment that may or may not need to be done by the installer in the field. That is the amount of counterweight needed. Theoretically everything should be perfect! In other words, all of these angles and the amount of counterweights are set at the factory for KNOWN

airplane applications. The history of the Aeromatic propeller shows that most of the time the factory settings are correct and the owner in the field needs only to make checks to verify the settings are correct.

The Aeromatic is designed so that at cruise the blade angle is at or close to the phase angle, in static full power it is at the low pitch angle, in a dive it will move toward the high pitch angle. These props have on average, about 18 to 20 degrees of blade angle change. However only about 4 to 7 degrees are used for all flight conditions. The extra high pitch angle is there to prevent over revving in a dive.

Note: I strongly recommend that you use a calibrated tachometer. Mechanical tachometers are notorious for being off calibration. Believe me, 200 rpm error is not at all uncommon. Also your propeller most likely will not perform correctly unless your tachometer is correct. Furthermore you can easily put your propeller into a dangerous vibration mode with a faulty tachometer. Calibrate your tach or buy that little hand held battery operated tachometer to do your rpm testing. If you send your propeller back to me with damage I guarantee you that I can tell if you have damaged it due to vibration.

THE AEROMATIC F200 (for flange shaft engines up to 180 hp)

A. Static full throttle regulation procedure. Assume a C-125* engine on a Swift with red line at 2500 RPM.

1. Remove all counterweights, bolts and nuts from the counterweight arms. Do not remove the counterweight arm clamp bolts. Check static full throttle RPM. If it is not 2500, correction can be made by use of low pitch stop adjusting shims located under the synchronizer cover plate. Remove the six screws and remove the cover plate. See note 1 below. One shim of .016" will change RPM by about 50. Removing a shim will decrease RPM adding a shim will increase RPM. Do not add or remove more than one shim at a time. If you can't get the right RPM by removing or adding a complete shim you can make finer adjustments by peeling the shims. See note2 below. After reinstalling the counterweights in their original position you will see a slight decrease in full throttle static RPM. This is normal, DO NOT make any more adjustments on static RPM.

Note 1. You may loose some oil by removing the stop bolts. Catch the oil in a container and replace it after you finish with the static rpm adjustments. Doing the ground runs with less than full oil will not hurt the propeller.

Note 2. The shims are peel shims. The shim is made up of .002" laminations. Therefore you can make finer adjustments to RPM.

B. Flight RPM Correction and Altitude Adjustment for Original Regulation.

1. With the counterweights install and secured properly make a full throttle level flight as close to your airport altitude as safely possible. Engine speed at full throttle level flight should be 2500 RPM.

2. If you find that the RPM is 2600, add one -2 counterweight to each side. This will reduce the RPM by close to 100. A -1 counterweight will reduce RPM by close to 50. If your RPM is 2400 you must remove one -2 counterweight from each side. All flight adjustments are done by adding or removing counterweights. You do not readjust your static RPM.

3. Aeromatic propellers will decrease full throttle RPM by about 20 for each 1000' increase in altitude. If your home base is at 3000' you would adjust your full throttle level flight RPM to be 2440. This will give you the best all around performance.

Note 1: If you have your propeller set up for home airport of say 3000 or 4000' MSL and you decide to fly and land at an airport at sea level you should be careful on takeoff from that field that you do not over speed your engine. If you move your home base to a sea level airport after having adjusted RPM for a higher airport you should re-adjust RPM by adding or removing counterweights. The late Art Scholl, a renowned aerobatic pilot, used an Aeromatic prop on his 200 hp Ranger powered Chipmunk. I have heard that he would carry a small kit of extra counterweights so he could make adjustments for the altitude at which he was performing.

* An Aeromatic propeller that has been factory set up for a Swift with C-125 does not use the same angle settings as used on a PA-20 with a C-125. So, you can not just take a prop from a Swift and bolt it on a PA-20 just because it uses the same engine. The difference in the speed of the airplanes demands different angle settings.

THE AEROMATIC MODEL 220 (for spline shaft engines up to 260 hp perhaps more in experimental airplanes)

The setup and adjustment procedure for the model 220 is the same for the model F200. The only difference is in the way, mechanically, the pitch stops are designed. The 220 uses four pitch stop bolts, two for high pitch and two for low pitch. Each blade has it's own high pitch and low pitch stop bolt. There are peel shims under the head of each stop bolt. If you have to make static rpm adjustments follow these instructions.

1. Remove the counterweights, bolts, washers and cotter pins. DO NOT REMOVE THE COUNTERWEIGHT ARM CLAMP BOLT. Do a static full power run. It should be at red line rpm. If it is too high you remove shims under the low pitch stop bolt heads. (These bolts are marked 1L and 2L, the other two bolts are marked 1H and 2H.) You must do the same to the both blades. If the rpm is to low you add shims. After you get the static full power rpm correct, secure the bolts with safety wire and be sure that the seal is good. Permatex #2.

CAUTION: These stop bolts carry virtually no load. They merely provide a stop for the blade pitch. Even though they are 3/8" bolts do not torque them to the 3/8" torque specification. Just make sure they are tight enough to provide a good seal.

Note: 1. You may loose some oil by removing the stop bolts. Catch the oil in a container and replace it after you finish with the static rpm adjustments. Doing the ground runs with less than full oil will not hurt the propeller.

Note: 2. As on the F200 propeller you will not be adjusting the high pitch angle. Your propeller likely will never go to the high pitch stop position.

2. From here you will use the same procedure to adjust flight rpm as detailed above for the F200 propeller.

OTHER INFORMATION

PULL TESTS PERFORMED BY TARVER PROPELLERS, LLC

THE RULES AND REGS

The FAR covering the design requirements for propellers says that all parts of the propeller shall have a safety margin of twice the calculated stresses. I now quote CAM 14.

"14.151 Centrifugal load test. The hub and blade retention arrangement shall be subjected to a centrifugal load equal to twice the centrifugal force to which the propeller is to be subjected in normal operation. Either one of the following two test methods shall be acceptable:

a. A one-hour whirl test, or b. A static pull test."

OK, so FAR 35 replaces CAM 14. Again I quote, "Sec 35.35 Blade retention test.

The hub and blade retention arrangement of propellers with detachable blades must be subjected to a centrifugal load of twice the maximum centrifugal force to which the propeller would be subjected during operation within the limitations established for the propeller. This may be done by either a whirl test or a static pull test."

We will now go into the technicalities and then present the results of my testing.

LOAD ANALYSIS.

A typical 0-85 blade exerts a total load of about 19,000# of centrifugal force. The sum of all side loads add up to less than 500# for a total of about 19,500#.

The screws have a minor diameter of 0.199 to 0.203" They are heat treated to tensile strength of 160,000 to 180,000 psi. Taking the worse case of .199 x 160,000 yields a breaking point of 4,976# each. With 18 screws in the 0-85 blade that equals 89,575# for destruction. Therefore we divide 89,575 by 19,500 we get 4.59 safety factor where only 2.0 is required by the FAR. That is taking the worse case screw diameter and the minimum heat treat. If we take the maximum screw diameter and maximum heat treat we get 5,826#. Multiply that by 18 and it yields 104,864#. That is a 5.37 safety factor.

All screws have 4.5" of threads, some have socket heads and others have hex heads. The function is the same regardless of the type of head and the length.

THE TEST RIG & HOW IT WORKS. This test rig can pull up about 40,500 pounds. See photos below.

Hydraulic fluid is pumped from the reservoir via the hand pump via the high pressure line into the hydraulic cylinder above the piston. Pressure is applied via the hand pump causing the cylinder to retract the ram creating the pull force. The pressure gauge reads the hydraulic pressure. By observing the pressure at the time the test article fails allows the total force to be calculated. For example. The bore of the cylinder is 4 inches. The area of the shaft is subtracted from the area of the cylinder and the result is 11.43 sq/in. Therefore if the pressure gage reads 2000 psi, by multiplying 11.43 times 2000 you get a total force of 22,860#. That's a bunch.

These photos show the hand pump, reservoir, calibrated digital pressure gage, 0 - 5000 psi and some plumbing.

(Click on any image for a larger view)

These photos show a typical arrangement for a pull test.

I have removed most of the long and boring details of all the pull tests from this web site. I think they have served their purpose. It is my decision now to just summaries the tests and results.

CONCLUSION.

I have performed a pull test on more than 134 screws. Not one screw failed to meet the performance requirements even though some of them did not meet the drawing as far thread OD is concerned.

None of the screw failures resulted in a break at the head, all screws failed at the first thread. This fact supports the analysis that screws found in propeller blades with the heads broken off logically points to the conclusion that they failed due to fatigue. That further strongly indicates the propeller has been subjected to dangerous vibration and/or used improperly. Further, screws in old blades that are found broken down at the first thread strongly indicated the the screws were not sharing the load evenly. This uneven load sharing is most likely due to one or more of the following; a) improperly torqued at the time of assembly, b) not properly torqued during overhaul and c) they, over a long

period of time, some of them began to loose some of their tension. This loss of even tension of some of the screws is pretty well verified when I do SB 2000-001A. By measuring the torque required to back out the screws I find that they sometimes vary considerably. The logically explains the broken screws.

This is the obvious conclusion especially in light of the data obtained from the pull tests I have performed.

It is clearly evident that the screws that I got with the rest of the hardware meet all performance requirements.

SERVICE BULLETIN

2000-001A

24 January 2003

TARVER PROPELLERS, LLC

1500 Rio Vista Dr.

Hangar C-4

Fallon, NV.

This Service Bulletin replaces Service Bulletin 2000-001 dated July 21, 2000

Propeller Blade Inspection

A. Background:

There is concern that a potential problem may exist in propeller blades of the models listed below. Many of these propellers have a manufacturing date as early as 1946. The concern stems from the obvious possibility that there can be detectable deterioration of the blade retention system due to moisture intrusion or vibration. Neither of these problems are specific to older propellers. Obviously the older the propeller the more opportunity for these condition to exist. The track record of these propeller blades, during the past years since 1946 indicate clearly that there is no unusual problem that has surfaced which would require drastic or emergency action. There is however, a better way to verify the airworthiness of these propeller blades. Past inspection criteria is in need of being updated, specifically in the shank retention area. This service bulletin addresses that need.

FAR 35.35 specifically states that a propeller shall have a blade retention safety factor of two. The retention system for these propeller blades have been tested and verified to have a safety factor of 4.2. Thus it appears that this is the strongest "link in the chain". This does not imply that it should be neglected.

Moisture Intrusion. These laminated wood propeller blades were assembled using a wood preservative. The material is a proprietary liquid by the name Nelsonite. Deterioration of the wood in these propellers is very rare. The Tarver Propeller company has found rusted retention screws in these blade yet had no wood decay. Some of the suspected wood was analyzed by the Forest Products Laboratory, a branch of the U. S. Agriculture Department, and was found to have no decay even though it was stained by iron oxide.

Vibration. Vibration, whether caused by an unbalanced propeller or engine is a matter that must be corrected. Vibration causes resonate nodes at various frequencies that are harmonically related to engine/propeller rpm which in turn can be aggravated by the dynamic loads on the propeller. This condition causes excessive stress on the blade retention system as well as the hub and of course the engine. Static balance of a propeller is valid. If the propellers is properly statically balanced, engine unbalance, if it exists, should be corrected, but not be unbalancing the propeller.

B. Requirements:

There are essentially two requirements addressed by this Service Bulletin. First is the need to bring a propeller, which is in an unknown condition of airworthiness, into a known condition of airworthiness. Second is the need for a more reliable inspection criteria.

Airworthiness Condition. Clearly there are situations in the field, for various reasons, where the owner/operator does not know the airworthiness condition of his propeller. An operator should not continue using a propeller that is in an unknown condition. After compliance with this service bulletin the owner/operator will have a propeller who's condition is established.

Inspection Criteria. In the past, the inspection criteria for the blade retention system consisted of verifying that each of the lag screws in the shank will accept 150 in/lb of torque without breaking or stripping the threads in the wood. Passing this test does not entirely verify the integrity of the screw. The Tarver Propeller company has found that a screw that passes this torque test can have enough rust on the threads that makes the part unairworthy. Many screws have been held in place so tight with rust that it is impossible to back out the screw without twisting it in two. Therefore a more thorough inspection method is detailed below which eliminates this ambiguity.

C. Affectivity:

This service bulletin is applicable to all Aeromatic propellers models F200, F200-H, 220, 220-1, 220H, all Flottorp (formerly Beech Roby) propellers models R100, R002, R003, all Beech Propellers models B200-100 (fitted with Flottorp blades FA200-244 and FA200-245), R201-100, R202-100, and R203-100 (fitted with Flottorp blades FA200-218, FA200-219 and FA200-220). The Aeromatic models listed above were originally manufactured by Koppers, then Unvair, then South 80, then Brown Propellers, LTD. The Beech models listed above were manufactured originally by Beech Aircraft Company, then Flottorp Manufacturing Company and Brown Propellers, LTD. Tarver Propellers, LLC is now the TC holder of the above model propellers and blades.

D. Compliance Requirements:

If the owner/operator has one of the above propellers which is in an unknown condition, then Tarver Propellers, LLC considers compliance with this service bulletin to be mandatory prior to putting it into service or continuing service beyond the times listed below.

E. Description:

This Service Bulletin provides information for visual inspection of all the above wood propeller blades for unsafe condition due to corroded lag screws and decay (dry rot) of the wood at the blade leading edge and at the interface of the blade and ferrule.

F. Instructions:

For those propellers that are judged to be in need of this inspection, the following shall be performed:

Part I. Initial Inspection for Blade Looseness between the Blade Shank and Metal Ferrule.

1. Prior to further flight, visually inspect each propeller blade for mounting security by pushing and pulling (with as much force that a man can apply with one hand on the tip) of the blade in a fore and aft motion. While exerting these forces, play can be detected by placing your thumb at the point where the wood blade enters the ferrule. Perform this inspection on both blades. If any motion is detected the propeller is sure to have broken lag screws and/or dry rot. Further flight is considered by Tarver Propellers, LLC to be unacceptable and should be grounded.

2. This test shall be performed before each flight. If no looseness (play) is detected, the airplane may continue operation until compliance to Part II of this Service Bulletin.

3. If any looseness (play) is detected the propeller may, depending on it's condition, be made airworthy by performing, by an FAA approved repair station, the following inspection and repairs.

a. The blades must be removed from the hub and inspected for broken, missing or the presence of unapproved lag screws.

b. Each lag screw shall be removed and inspected for corrosion and meet the dimensions on the drawing applicable to the screw part number. See note 1.

c. The ferrule shall be removed from the blade in order to gain unobstructed access to the wood for inspection. The ferrule may be reconditioned as necessary and reused. See note

d. The blade shank perimeter, screw holes and balance weight holes shall be inspected for wood decay, cracks or delaminating. See note 3.

e. The ferrule shall be reinstalled on the shank in the same clock position as it was prior to removal. See note 4.

f. If the propeller blade is finished with plastic coating, the interface where the ferrule meets the coating shall be sealed using spot putty or plastic patch or a combination of both depending on how much area has to be covered.

g. If the blade doesn't have plastic coating, then spot putty may be used to reseal the area. The lag screws shall be reinstalled and torqued before the seal has dried.

h. The lag screws shall be dipped in Nelsonite, installed into a screw hole and torqued to 150 in/lb in addition to running torque. See note 5.

i. The metal leading edge/tipping shall be inspected in accordance with Service Bulletin 25C.

Note 1. All lag screws shall be removed using reverse torque. If the screw breaks during reverse torque it is a virtual certain sign of excessive corrosion. A blade may be returned to service with no more than 2 missing or broken lag screws in the outer circle. Broken or missing screws shall not be adjacent to each other except within the inner circle. All the rest of the screws shall meet the dimensions

on the drawing and meet the installation criteria of Part I, 3) h. Lag screws that are to be installed shall bear no signs of rust.

Note 2. The ferrule may be cleaned of surface corrosion and corrosion proofed either by cad plating, per applicable drawing or zinc chromate primer. Deep corrosion pits anywhere on the ferrule is criteria for rejection.

Note 3. Inspect the wood using a sharp tool that can be used to probe the wood in various places in and around the exposed shank. The screw hole threads shall be inspected for damage with a borescope. Look for any visible cracks in the wood in the screw holes and any obvious gross damage to the threads. Small cracks in no more than 3 screw holes and if, later, the screw will meet the torque requirements of Part I, 3) h, then this is not criteria for rejection of the blade. Cracks that connect two or more screw holes is cause for rejection of the blade. Most blades contain some amount of lead wool in the center balance hole. This lead may cause a whitish stain near the lead and is not criteria for rejection unless the wood is found to be soft using the sharp probe. Various degrees of brown stain will virtually always be present on the wood and is not the deciding criteria for rejection of the blade. Soft spots in the wood is criteria for rejection.

Note 4. The ferrule will have a small hole drilled in the side wall and a matching hole will be found in the shank of the blade. Be sure that these holes match up when reinstalling the ferrule.

Note 5. The ferrule shall be reassembled onto the blade shank. Screws of the same length as was removed shall be used to reinstall the ferrule. After all screws have seated against the ferrule, all of them shall be re-torqued at least EIGHT times. This assures a uniform strain among the screws. THIS IS IMPORTANT.

Part II. Repetitive Inspections The inspection detailed in Part I shall be performed any time the condition of the propeller blades becomes unknown or when any looseness of a blade is detected as detailed in Part I "Prior to Further Flight".

G. Summary:

This inspection requires that the propeller be disassembled, reassembled, check for blade angles, balanced, pressure check the hub, and add lubricant. The estimated time to perform this, assuming no repairs or part are required, is 8 to 12 hours.

This bulletin may be complied with by an appropriately rated propeller repair station or by Tarver Propellers, LLC.

Telephone and FAX 775-423-0378

TAKE CARE OF YOUR PROPELLERS, FELLERS. HERE IS HOW . First I want to comment of some of what I've seen come into my shop. And this is most likely nothing new to many of you pilots. Some of these props look like someone flew through a gravel pit. I mean the leading edge on some of them are really beat up, beat up so bad that the entire metal leading edge has to be replaced.

Anyway, here is how you can increase your propeller reliability, life span and safety. To stop FOD do the following:

THE NEVER DOs

Never do a run-up except into the wind. Never do static run-up except on hard surface and even then do it into the wind.

THE ALWAYS DOs

If you are on gravel, sand or dirt/grass.

Always start your engine with the airplane pointed into the wind if not on paved ramp. Always start your taxiing into the wind, after it is moving about like a fast walk then make your turn down wind, keep it moving, if a down wind taxi is required. Always do your mag check on takeoff roll if you are not on paved ground. After a down wind taxi to the takeoff end of the runway, do not stop, keep it moving and do a U-turn into the wind and ease in the power.

Find out by experiment what the maximum RPM you need to start taxiing your plane and yet will not pickup gravel and other trash, and use that RPM or less always.

I've been flying into Baja California, MX since 1976. I've made hundreds of landing and takeoffs of unpaved ground down there. I've flown Tri-Pacers, A C-150, My C-182, my Cruisemaster, two different Cruisair Bellancas and my Apache. My Apache has minimum legal prop tip clearance and since 1985 I've made many takeoffs on gravel. Those prop blades show only very slight sand dings, not even enough to require fixing, and that was most likely picked up on paved run-up pads.

Now, a twin is a little more difficult to do a mag check on takeoff roll because you only have 3 or 4 seconds to do them. So I don't do mag checks on takeoff roll. I merely make sure, during taxiing, that there is no dead mag.

It's is becoming more clear that the editors of journals will not give forum to readers if the reader writes to the editor and disagrees with some of the material that they publish which may offend one of their advertisers. For example, I wrote to AOPA Pilot explaining how nearly useless oil analysis is and how oil filters may be a move in the wrong direction vs an oil screen. Of course since they accept advertising from oil analysis companies and filter mfg companies, they chose not to print my comments. Below is another example of how the journal General Aviation News choose to ignore my letter to Mr. Visser, at least so far anyway. My letter was written in Nov. 05.

the power.Maybe I will start my own news letter and add it onto the tail of my web site. I'll see if I have time to do so.

__________________________________________________________________________________________________________________________________________________

I think I am going to start a little column of my own on this web site. I get a little irritated at the expert aviation journalists when they write articles that contains errors and when they are corrected they elect to ignore it. I find that most writers would rather sweep their mistakes under the rug instead of eating a little crow. I think that sort of thing goes with the egomania of some pilot-writers. Don't misunderstand, there are some really good ones out there. You can recognize them because their humility shows in their writing. You can also recognize the egomaniacs because their self esteem and great ego also shows through their writing hand. There is one character that writes for Flying who's ego is always about 5 or 6 flight levels above his cruising level.

I also have an ego, who doesn't? I've made mistakes, who doesn't? I can also eat crow. I have never seen one of the "great aviation writers" eat crow. All they do is ignore you or justify themselves. But, eat crow, no way Jose. I have, over the years, had some of them admit error directly to me but never publish it in their journal.

____________________________________ MAYBE I WILL, OR NOT, I'M STILL THINKING ABOUT IT ______________________________________________________

THE FOLLOWING IS A LETTER I WROTE TO BEN VISSER OF GAN. I sent this in Oct. 05. As of Mar 06 he has ignored it. I reckon this is typical of the experts.

Dear Ben, I understand that motor oil does not break down with use. I understand that it can not hold in suspension metal particles large enough that can damage the engine. I was told by Lycoming that the screen will catch any particles large enough to damage the engine. I have seen small metal particles imbedded in the Babbitt bearings when the engine went way past TBO. I also understand that with a filter they (I reckon the filter mfg co.) recommend keeping the oil in the engine for 50 and sometimes 100 hours before changing it. So I reckon that the main reason for removing the oil and replacing with fresh is because the oil gets contaminated with acid (sulfuric?) and or water. Assumptions: a) After an oil change and a flight of 5 or 6 hours then there is the possibility that moist air can be drawn into a cooling engine and the water vapor in the air can condense into water. Since most petroleum based products contains some sulfur then with the water present we get sulfuric acid. b) Then on the next flight if you then run the engine long enough to bring oil temperature up to normal then the water vaporizes out and the sulfuric contained in the oil can't damage the engine. So the process is cyclic. c) Logically the screen/filter removes solids that can damage the engine and the next flight removes (by heat) the liquid contaminants. In my past 50 years of flying I have religiously changed oil every 25 hours. In my Geronimo I ran one factory reman engine with a top OH to 3905 hours and the other factory reman engine to 3150 hours. In both cases I found, at an oil change, more metal in the screen (I don't use filters) than I was comfortable with before engine overhaul. In both cases I had routinely practiced oil analysis at each oil change. I didn't tell them that I found lots of metal in the screen. In both cases their analysis came back "normal amount of contaminants". After which I told them about all the metal and they said "Oil analysis only detects particulate matter that remains suspended in the oil". I will never go more than 25 hours without pulling the screens. And in the two above cases I firmly believe that if I had been practicing running the engines 50 to 100 hours without inspecting the screens I would have had a catastrophic engine failure. I'd like your comments on that. Now my question: Do you see any reason why, when I pull screens for inspection at 25 hours, I should not run the oil for 50 hours, or even 100 hours for that matter? Now I realize that you worked for Shell and you, that is Shell, wants to sell as much oil as they can. But you are retired now and I don't think you are any longer in a position of conflict of interest, unless perhaps you feel an obligation to them. We are now living at a time when the price of petroleum products are headed for earth orbit. I think that anything that can be done to reduce our dependence on petroleum products should be done.

With pure logic can you give a technical reason why this idea is flawed? Thank you. Kent Tarver