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Propeller flange bolt size question

O

Ofitz

Member
I finally got my RV-4! The first thing I want to change though is the prop!!

I have a sensenich 68" fixed pitch composite prop, I want to get the sensenich ground adjustable 72"....

I can't seem to verify the prop bolt size.... I am seeing conflicting information on different websites.

I have an O-320-D1A engine. Are the bolts 7/16" or 3/8".... ????

Thanks for the help!
 
Take the spinner off and see what wrench fits the bolt. Too many after market things done to experimental aircraft to assume an engine set up is what it used to be.

9/16 wrench = 3/8 bolt

5/8 wrench = 7/16 bolt

The engine side and the prop side may not be the same bolt size depending on the prop extension.

A Sensenich will have the same size bolt because it goes through the prop and the extension to the engine.

A Catto prop could be configured with different sizes because the prop bolts go through the extension only. There are different bolts that go through the prop extension to the engine.
 
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A 9/16 fits on there. I was hoping I was doing something wrong because the "new" sensenich prop requires 7/16.... not 3/8..... I'll call them tomorrow to see what they can do about it...

Thanks for the help!
 
My O-320-D1A is equipped with 7/16 prop bolt drive lugs. If yours has 3/8 then it's pretty easy to press them out and install 7/16. You'll love the Sensenich GA prop. It's a bit pricey but works fantastic. You might also want to try to locate a Landoll inertia ring to bolt onto your flywheel. I have that on my RV-6 and it really smooths things out.
 
I'm so new to all this that I am just trying to assimilate the information.

I did not know that you could press out the inserts. That's cool. I have help so I'm sure I could do that fairly easily.

Is the inertia ring similar to a dynamic balance?
 
The solid metal ring, like I have, just adds rotational mass/inertia to the flywheel to make everything run smoother plus get a bit more weight shifted forward, which is an issue with the RV-6's CG when you have an O-320 engine and a lightweight wood or composite prop. The ring helps the engine/prop combo to idle at lower rpms plus run much smoother overall at any rpm below 2400.
 
The ring is something to consider. I should look at how much this will affect the CG as well.

I looked at everything again and the plot thickens. I have 7/16" bolts connecting to the flywheel, a 4" spacer, then 3/8" bolts connecting to the sensenich prop....

So I guess Saber can make the appropriate spacer because sens only includes a 2.25" spacer....
 
Prop Bolts

The Van's instruction book lists all the O-320 engines (and others) and the similarities and differences if you got one with your plane. My brother and I built an RV-4 with the Sensenich ground adjustable propeller and we have the steel ring. It is not a damper. It was necessary to move our CG forward.
 
Prop bolts

Our RV-4 has a O-320 E2D with 7/16" bolts. The Sensenich ground adjustable propeller is only available with the 7/16" bolts.
 
When you're ready to order the prop, call Sensenich and tell them you need the 4" spacer and bolts and they'll know exactly what different hardware you need to get.
 
Absolutely! It's a Sensenich W68T6EM82 wood prop. I have all the engine logs since new so I can give you more info as I get the new prop installed.

I am using a 4" prop spacer and it's taking a bit to get everything coordinated. Once I get it done, I will post back.

What engine are you using it on?
 
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