P

Papa

Well Known Member
I'm installing a Hartzell prop on my RV-8, and had a question for anyone who has been through this. The manual calls for torquing the flange studs to 60-70 ft-lbs. Unfortunately because the the design, I cannot get a socket on the studs, and must use an open-end/crowsfoot type end. The manual shows using a torque wrench extension, but after searching the internet for about an hour, I can't for the life of me find one. Hartzell sells one, but at $501.00, I can't justify it. Does anyone know where I can find such an animal an a reasonable price?

Thanks in advance for the help.

Papa, RV-8 finish-kit
 
yup!

Simply take a 3/4" open ended wrench and an old 1/2 drive socket and weld the socket onto the handle of the wrench.

Put the middle of the socket on the handle at 6" from the middle of where the bolt will be in the open ended wrench.

If you can't get this done locally let me know and I'll make one for you for the cost of the wrench plus postage.

Incidently on Dan Checkoways site you will see a conversion calculator that will give you the setting to put on the torque wrench.

Cheers

Frank
 
Incidently

I don't believe a crows foot will fit either, according to my friend who tried it.

Frank
 
Depending on the torque wrench design, the crows foot might work. It does with mine, but just barely. I think Aircraft Tool Supply sells a tool for ~$50 or less.
 
Papa,
I have a Hartzell on my 0-320 with smaller 5/8? nuts which are tightened to 45 to 55 ft/lb so I don?t know if this will apply to you (I assume you have the larger hartzell with 3/4"?? nuts). At first I used a modified good quality open ender. For various reasons I had to re-install the prop a couple of times after which the nuts were starting to show some rounding on the shoulders and the open ender was starting to spring open somewhat. I then got two new identical open enders which will both fit on the nut at the same time. Slipped a length of one inch steel pipe over both the spanners and placed a spring scale (checked for accuracy) on the pipe at two feet from the nut and tightened to about 25 lb on the scale (about 50 ft/lb). Using two spanners at the same time prevented any further damage happening to the nuts. You can of course, use the pipe on a single spanner. If you try this be careful nothing slips and hits you on the face/body as you pull on the spring scale.

Fin 9A
 
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Thanks for the help!

Thanks for the help everyone. It seems like this project has always been two steps forward, one step back, but I am making progress and with any luck will be flying this fall some time. I don't know how people did it before the internet!

Papa
 
I just used a shorty 3/4 open-end/box end wrench. I cut the top off an old sparkplug socket which fit in the box end of the wrench. When I cut the hex head off the socket wrench, I left a lip, so when you put it on the end of the torque wrench the socket head captures the wrench. I then did the the calcuations for the extension to determine the proper torque value.

If you would like to have a copy of the spreadsheet to calculate the new torque values, give me a shout.

[email protected]
 
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