I have started installing the prop and have finished the back plate and doubler. I have removed the locking nut on the four bolts to fit on the plate. There is a 1/4x3/8 spacer and three washers per bolt. The drawings are not clear on the order of placing the plate/doubler on the prop. Is the order:spacer, three washers, plate w/doubler then locking nut? My instructions say use temp non locking nuts first and then use the locking for final installation. Did you use one, two or three washers per nut? This would change the depth of the plate relative to the blades.
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Help installing a Hartzell BA
- Thread starter 129TG
- Start date
Thom,
I just did this. You use the washers as necessary to make a snug fit of the spinner against the forward bulkhead as well as the backplate flange. I believe it says in the instructions that you can use a maximum of three washers as necessary to make sure the forward bulkhead is snug up against the spinner (look at Figure 3-4 in your prop manual for the sequence, upper right corner). If there's any space at all between the forward bulkhead and the spinner, you will end up with dimples in your spinner and a possible wobble with the engine running.
I would find 4 castle nuts to use as temporary nuts because you may have to remove the backplate a couple of times to get it just right. Once you have determined the appropriate number and sequence of washers, use the lock nuts supplied with the prop, torque, and mark the nuts with torque paste.
I just did this. You use the washers as necessary to make a snug fit of the spinner against the forward bulkhead as well as the backplate flange. I believe it says in the instructions that you can use a maximum of three washers as necessary to make sure the forward bulkhead is snug up against the spinner (look at Figure 3-4 in your prop manual for the sequence, upper right corner). If there's any space at all between the forward bulkhead and the spinner, you will end up with dimples in your spinner and a possible wobble with the engine running.
I would find 4 castle nuts to use as temporary nuts because you may have to remove the backplate a couple of times to get it just right. Once you have determined the appropriate number and sequence of washers, use the lock nuts supplied with the prop, torque, and mark the nuts with torque paste.
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IIRC, my order is spacer, washer, back plate, washer, nut. I might have a washer between the spacer and prop hub...but I can't remember.
Ultimately you are after spinner fitup between the two plates on the prop as well as spacing to the cowl. You may need to adjust the back plate or front plate as required to get everything to fit right.
Ultimately you are after spinner fitup between the two plates on the prop as well as spacing to the cowl. You may need to adjust the back plate or front plate as required to get everything to fit right.
Thom,
Yes, on the bench. Also, besides trimming the spinner for the blades, I would go ahead and install the blocking plates behind the blades. It's a lot easier to set the rivets on the backplate flange for the blocking plates with the prop on the bench. As a matter of fact, I would complete the spinner installation before torquing the 4 nuts that hold the backplate on. You probably will need to take the backplate off to rivet the blocking plates on as the rivet squeezer interferes with the prop blades. I took a piece of 3/4" plywood and drilled for the prop bolts and then set the plywood on a bucket to use as a prop stand.
By the way, after you mount the prop on the engine, I would get a helper and between the two of you twist the prop blade through its range to make sure no part of the blade touches either the spinner or the blocking plates. You may have to do some further trimming after performing this maneuver!
Yes, on the bench. Also, besides trimming the spinner for the blades, I would go ahead and install the blocking plates behind the blades. It's a lot easier to set the rivets on the backplate flange for the blocking plates with the prop on the bench. As a matter of fact, I would complete the spinner installation before torquing the 4 nuts that hold the backplate on. You probably will need to take the backplate off to rivet the blocking plates on as the rivet squeezer interferes with the prop blades. I took a piece of 3/4" plywood and drilled for the prop bolts and then set the plywood on a bucket to use as a prop stand.
By the way, after you mount the prop on the engine, I would get a helper and between the two of you twist the prop blade through its range to make sure no part of the blade touches either the spinner or the blocking plates. You may have to do some further trimming after performing this maneuver!
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Just completed the spinner install a few weeks ago
Here is my experience.
I performed all the work on the bench.
I test fit the rear plate to the spinner to see how good a fit it was and whether there was some excess on the spinner that needed to be trimmed. With the rear plane inside the spinner I saw about 1/8" of excess spinner that I thought would need to be cut off. I decided to wait (A VERY GOOD DECISION) until I had the spinner completely mounted to the prop.
I mounted the backplate to the prop with the spacer and one washer per the plans. I used a small square resting against the prop blade and the back plate to mark the back plate where I would expect to make my first blade cut outs in the spinner. I then made my own template out of some cardboard (not a big deal) and fit it to the prop and backplate. I then removed the backplate and placed the spinner on top of the plate. I transfered the marks I made using the square from the backplate to the spinner so I now had a reference for the template. With the spinner off I taped the template in place and marked the spinner for the cutout. Using a Dremel I the spinner. I knew this was going to be my first rough cut so I wasn't too worried while cutting it.
Then I remounted the backplate (spacer and 1 washer) to the prop and installed the front plate (without any spacers) and mounted the spinner. To my surprise the front plate determined the FWD and AFT position of the spinner, not the backplate. And the 1/8" of excess material I thought I had on the spinner that needed to be removed wasn't there. It was almost perfectly aligned with the back flange of the back plate. However there was now a gap between the spinner inner surface and the back plate flange. I could have left this gap (~.020") but I have seen many RV's with pillowing around the spinner mounting screws and leaving this gap would cause this. So I decided add some fiberglass to the inside aft surface of the spinner.
I trimmed the cutouts with 1/4" clearance around the blades. I made my gap plates out of aluminum and had to trim a bit more then 1/4" behind the blade to provide clearance for blade rotation.
It took some time but it all worked out well.
Here is my experience.
I performed all the work on the bench.
I test fit the rear plate to the spinner to see how good a fit it was and whether there was some excess on the spinner that needed to be trimmed. With the rear plane inside the spinner I saw about 1/8" of excess spinner that I thought would need to be cut off. I decided to wait (A VERY GOOD DECISION) until I had the spinner completely mounted to the prop.
I mounted the backplate to the prop with the spacer and one washer per the plans. I used a small square resting against the prop blade and the back plate to mark the back plate where I would expect to make my first blade cut outs in the spinner. I then made my own template out of some cardboard (not a big deal) and fit it to the prop and backplate. I then removed the backplate and placed the spinner on top of the plate. I transfered the marks I made using the square from the backplate to the spinner so I now had a reference for the template. With the spinner off I taped the template in place and marked the spinner for the cutout. Using a Dremel I the spinner. I knew this was going to be my first rough cut so I wasn't too worried while cutting it.
Then I remounted the backplate (spacer and 1 washer) to the prop and installed the front plate (without any spacers) and mounted the spinner. To my surprise the front plate determined the FWD and AFT position of the spinner, not the backplate. And the 1/8" of excess material I thought I had on the spinner that needed to be removed wasn't there. It was almost perfectly aligned with the back flange of the back plate. However there was now a gap between the spinner inner surface and the back plate flange. I could have left this gap (~.020") but I have seen many RV's with pillowing around the spinner mounting screws and leaving this gap would cause this. So I decided add some fiberglass to the inside aft surface of the spinner.
I trimmed the cutouts with 1/4" clearance around the blades. I made my gap plates out of aluminum and had to trim a bit more then 1/4" behind the blade to provide clearance for blade rotation.
It took some time but it all worked out well.
