PowerfinProps.com

 

Assembly Instructions For Your New Powerfin Propeller

Congratulations for purchasing a Powerfin propeller with the new Speed Set hub (U.S. patent pending). You now own the finest carbon fiber composite propellers available for the ultralight and small experimental industry. You are responsible to read and apply the information given to you in this instruction sheet in order to safely mount and operate your new Powerfin propeller. Take the time to read through the entire sheet BEFORE YOU ATTEMPT TO USE THIS PRODUCT. Failure to understand and apply this information could put you at risk of bodily injury and death. Having said that, we are sure you will find that following the assembly directions carefully will allow you to quickly and very easily mount this propeller and set the pitch very accurately.

We have made every effort to insure you have received a product that will meet your expectations for years to come. We offer a generous warranty on our propellers. Powerfin propellers are warranted for two years against any delamination or factory defect of any kind. This warranty will not cover customer abuses such as operation in abusive environments, prop strikes, foreign object strikes, improper assembly, or operations on non-approved applications.

Packing List

Included in your package you will find the following items:

For a three blade propeller:

1. Three individually wrapped propeller blades.
2. One propeller hub in separately wrapped halves.
3. Six 80mm x 8mm socket head bolts.
4. Six 40mm x 8mm socket head bolts.
5. Twelve 8mm high collar split ring lock washers.
6. One 1/4" x 2" steel dowel pin.
7. Six 8mm nylox locknuts.

For a two blade propeller:

1. Two individually wrapped propeller blades.
2. One propeller hub in separately wrapped halves.
3. Six 80mm x 8mm socket head bolts.
4. Four 40mm x 8mm socket head bolts.
5. Ten 8mm high collar split ring lock washers.
6. One 1/4" x 2" steel dowel pin.
7. Six 8mm nylox locknuts.

Assembly Instructions

You will need a few specific tools to mount your new propeller. PLEASE NOTE: You MUST use a good quality torque wrench to properly assemble this propeller. The wrench must be able to apply 175 INCH POUNDS of torque. INCH pounds! You will also need a standard set of feeler gauges and a 6mm socket wrench that is compatible with your torque wrench. Most local hardware and auto parts stores carry these items.

We have provided pictures below to help you understand the following assembly instructions. The numbered pictures correspond to the assembly steps listed below. Please FOLLOW THESE INSTRUCTIONS CAREFULLY. Whenever you do any work near your vehicle be ABSOLUTELY SURE that your ignition switch is OFF. An engine with a hot ignition can kick when you turn the propeller by hand and seriously injure you.

1. The propeller hub has two distinct halves. One half has the outside retaining bolt holes threaded and NO square cut window holes in the blade cavities. Additionally, this half does NOT have the Powerfin Inc. logo and toll free number inscribed on it. Place this half on a large flat table with the blade cavities accessible. This is the half that will touch the prop mounting flange or pulley on your engine after it is mounted.

2. Powerfin blades have a small hole drilled into the root of the blade. This hole will be located on the same side of the blade that the Powerfin Inc. product label is affixed. If this is not the case please contact Powerfin Inc. for specific instructions. Place a blade into each blade cavity in the hub such that the hole and the product label face up.

3. Place the other half of the hub over the assembly. The product labels on both the blades and the hub should be facing up. Additionally, the small holes that are drilled into each blade should be viewable through the small square windows which are cut into the hub. If this is the case, use one of the split ring washers on each bolt and fasten all of the outside retaining bolts (40mm x 8mm) in position. Finger tighten them to the point where you can pick up the assembly and it isn't so loose that the blades flop around.

4. Tighten the outside retaining bolts down with a wrench monitoring the gap between the hub halves to make sure the bolts are going down EVENLY. When we say EVENLY we mean the two retaining bolts on each blade relative to each other. This is especially critical on the two bladed propeller hubs. If one side is tightened down prematurely, the hub halves will not be parallel and the accuracy of the pitch setting will suffer. Generally, if you cannot see a clear difference between the gap between the hub halves on each side of a blade, you will be accurate enough. The objective of this step is to make sure that the outside retaining bolts are down as tight as possible but still allow for a turning movement of each blade without a lot of force.

5. Pick up the entire assembly and place one hand on a blade and one hand on the hub. Pull and turn the blade HARD so that the blade seats in the hub cavities all the way out as far as it can. Also make sure that the small hole ends up in the middle of the square window of the hub. Do this on every blade. At this point your propeller is ready to mount on your aircraft.

6. Place a split ring washer on each mounting bolt (80mm x 8mm) and insert them into the mounting holes. Place the propeller hub onto the propeller mounting flange making sure that there is no dust or debris between the propeller hub and the flange. Make sure it goes down flat. DO NOT attempt to force the propeller hub flush to the flange with bolt torque. Failure of any propeller hub to lay flat against the flange is indicative of a problem which must be addressed. Tighten the six mounting bolts so that they just begin to depress the split ring washers and stop there. Make sure the blades still turn in the hubs without too much effort. Loosen each bolt evenly in very small increments if you must.

7. It is a good idea to do things methodically when setting the pitch on your propeller. Making sure the ignition switch is off, turn the prop so that one blade is in a horizontal position and is comfortable to work with. When you're ready for the next blade, turn the prop so that the next blade is in this same comfortable position. You will find that it is much easier to work this way than attempting to turn your hands and arms to accommodate each blade.

8. Place the 1/4" x 2" steel dowel pin into the hole in the root of the blade. Make sure it goes in at least 1/2". It doesn't matter how far you push it in past 1/2" as long as you don't push it so far that you can't get it out with your fingers again.

9. The Speed Set feature on Powerfin hubs makes this job simple. Combine the proper feelers on your feeler gauge to make .095". This thickness is pre-determined to provide you with a pitch setting that is generally conducive to your application. There will, of course, be exceptions to this but the vast majority of applications will end up near this setting. This is because we generally drill the hole in each blade according to the use known of that blade. .095" will index the pitch of the blade such that it comes close to proper RPM during a static run-up. There is a reference chart for tip angle and feeler thickness on the photo pages. This will let you know what tip angle you have for any selected thickness. You can use this information when discussing pitch issues on the phone with Powerfin or other manufactures.

10. There are two places where you can put the feelers - on one side of the pin or the other. On pusher applications you'll use the side that corresponds to the leading edge (the one with the stainless steel tape on it) of the prop blade. On tractor applications, you'll use the side of the pin that corresponds to the trailing edge of the blade. Place the feelers into the gap between the pin and the edge of the window. Make sure they are centered from side to side in the gap and that they are also parallel to the pin and perpendicular to the blade. Next, turn the blade so as to squeeze the feelers between the edge of the window and the pin.

11. Holding enough turning pressure on the blade to keep the feelers from falling out, begin to EVENLY apply torque to the outside retaining bolts until the blade is secure and will no longer turn in the hub. Once complete, gently walk the feelers back and forth to remove them from the window. Pull out the pin and proceed to the next blade. Repeat steps 10 and 11 for each blade and proceed to step 12.

12. Once all the outside retaining bolts are down tight enough to keep the blade from turning, you'll find that the inside mounting bolts need a little tightening to bring the hub back flush to the propeller mounting flange. This time bring all the inside bolts down until the split ring washers are squashed flat but go no further. Next, increase the bolt pressure EVENLY by going only a half turn on each bolt and switching to the opposite bolt in the bolt pattern - much like you would criss cross when changing a tire on a car. Bring the bolts down fairly tight so that you are near final torque.

13. Select 175 INCH POUNDS on your torque wrench. INCH pounds! Begin applying torque on the outside retaining bolts first. Bring the torque down EVENLY in small 1/4 turn increments switching back and forth between the two bolts on the blade until final torque is reached. Proceed to the next blade and finish torquing all the outside bolts before proceeding to the inside mounting bolts. When torquing the inside mounting bolts, be sure to alternate in a criss cross pattern as you tighten the bolts. You will have to go around several times to achieve proper torque due to the incremental compression of the hub. When each bolt holds 175 inch pounds of torque you are ready to do a static runup of your engine.

14. With the vehicle secured, start your engine and allow it to warm up to proper running temperatures according to the engine manufacturer. Once temperatures are up you can advance the throttle to see how the propeller loads it down. Don't throw the throttle all the way to maximum right away. Bring it up slowly to be sure that there is no adverse vibration or temperature issue. Also, you want to make sure that your engine won't exceed red line RPM at any throttle setting. If full throttle results in an RPM that is at or slightly below maximum power and well below red line RPM, you are ready to fly. Your propeller is set up correctly when the RPM is slightly below maximum power RPM when the aircraft is climbing out. See below for pitch changing tips if this is not the case.

Pitch Change Instructions

If you have done a runup and have determined that further adjustments are necessary, you must go through a shorter process than described above to make a pitch change. If your engine went past the desirable RPM you need to increase the pitch of your propeller blades or "take a bigger bite" out of the air. Conversely, if your engine did not achieve the desired RPM at full throttle, you need to reduce the pitch and take a smaller bite. To do this you must select more or less feelers depending on which way you have to turn the blades. The chart below will help you to determine this. This chart assumes that you have followed the above instructions carefully and your prop is pitched as instructed above.

To increase pitch on a tractor and decrease RPM - add to the original .095".
To decrease pitch on a tractor and increase RPM - subtract from the original .095".
To increase pitch on a pusher and decrease RPM - subtract from the original .095".
To decrease pitch on a pusher and increase RPM - add to the original .095".

The next question is how much to add or subtract. The answer is not to make changes in very large amounts. One degree of pitch change is .020" on the feeler gauge. If you have a normal application your engine should have come fairly close to the RPM you need during static runup. If it was within 500 RPM, don't make changes with any increment larger than .020"

One important thing to understand when changing the pitch is to never use a combination of feelers in excess of .125". That is the simple rule. When you reach the point where you need to add more than .125" of feelers, simply calculate the difference between what you want and .125", subtract that difference from .125", and use the other side of the pin and force the blade into the feelers on that side from then on. For instance; if you were reducing pitch on a pusher and were using the slot which corresponds to the leading edge of the blade, you would be adding thickness to stop the blade at a lesser angle. If you got to the point that a .120" thickness was not quite enough and .135" might be perfect, simply find the difference between .125" and .135". Subtract .010" (the difference) from .125" and you'll get .115". Select .115" feelers only this time put them on the other side of the pin and turn the blade in the opposite direction to squash them against the other side of the window. From then on, instead of ADDING feelers to decrease pitch, you'll have to SUBTRACT feelers to decrease pitch. If you find yourself subtracting so many feelers that you have no more, you are out of luck with this method of changing pitch. You can set the pitch with any protractor, digital level, or other angle finder.

When you are ready to make the pitch change, loosen each bolt exactly 1/2 of a turn. Check to see if the blades will turn in the hub. If not, continue to loosen all the bolts by exactly the same amount until the blades all turn in the hub without too much effort. Repeat steps 9 through 14 to finish making the pitch change. This process should only take a few minutes to do. You may wish to experiment to find the perfect pitch settings for both cruise and climb performance. By remembering the settings for each, you will be able to quickly set your propeller for the type of flying you wish to do that day.

Once you have your propeller set how you want it and have flown it once, check the torque on all the bolts. Do this a few times in the first five hours of operation to be sure there is no loosening of the bolts. Typically, you will see a little movement during the first few checks. After that everything should settle down and stay tight. There are several things you can do to stop this if it keeps reoccurring. You can use blue Loctite if you so desire. Another thing you can do is to drill out the heads of the mounting bolts to safety wire them. We have great difficulty locating pre-drilled metric bolts for this application or we would have provided them. We have provided locknuts to use on the back of your propeller mounting flange if there is room to mount them. Those engines which do not have flat areas to mount the nuts will have to use one of the other methods or just get used to checking the bolts every 10 hours. If there is room to mount the nuts, just use moderate wrench torque to tighten them down. Do NOT use any washer under the nut. Check torque often on the outside retaining bolts. Once every 10 hours should be sufficient.

Maintenance Instructions and Tips

Powerfin propellers should be fairly maintenance free aside from the occasional torque check and cleaning. This section is more geared for providing tips on how to keep your propeller looking new and presentable.

The main cause for surface deterioration of Powerfin propellers is UV light - sunlight. Although there are special chemicals mixed into our finish to help ward off the effects of sunlight, the effect of long term exposure to sunlight will be to dull the shiny finish your propeller came with. There is no structural issue to concern your self with. Powerfin propellers are cured at very high temperatures. Direct, long term exposure to the hot sun cannot affect the structural integrity of them. The only thing to concern yourself with is the glossy finish. To help deal with this it is recommended that you always keep the propeller clean and apply a wax of some sort to the blades. Most paste type car waxes add another coat which protects against UV. It will usually say so on the can if it does. Avoid liquid waxes. They frequently contain solvents which could be harmful to the finish of your propeller. Acetone will not hurt the finish of your prop and can be used to clean stubborn residue. Generally, soapy water will clean most anything that can accumulate on your propeller.

Bugs are another cause of superficial damage. Bug guts are highly acidic and, if left on the propeller for too long, will eat small little pits in the finish below them. Get them off with soapy water as soon as possible to avoid this kind damage. Once this kind of damage occurs, that beautiful finish is gone forever.

Lastly, the urethane leading edge tape is replaceable by the customer. It should be replaced if it gets too chewed up. The cost is very low and the result will be a great lengthening of the life of your propeller. If you continue to run the prop in abrasive environments with rips and tears in the tape, the composite structure below will not take long to deteriorate. Urethane replacement tapes are available from PowerfinProps.com. at a reasonable price.

We hope these instructions are clear and concise. If you have any difficulty assembling or setting the pitch on your propeller, please feel free to call the toll free number.

HOME