[Jamie Aust]

Not being able to see an RV3 or an RV4 in my area, I was wondering what size the empennage of the RV3 is. Would any one here know if you could use an RV4 emp instead of the non match drilled RV3.

The only thing that doesnt look the same is the fwd VS spar attach point, also a little in the trim tab area.

It also looks as if you have to make all the HS to elevator brackets from raw stock , when you could use the ones that we already get with current kits.

I was thinking along the lines of when you can fit a RV7 emp on the RV6 fuse.

Now that my 7A has been flying for over 1 year now, and just starting to help a mate with his new RV8 emp, im missing the joy of building again, and an RV3B looks like fun with QB wings and maybe an RV4 emp ? That just leaves the fuse ( non matched drilled )

 

[Michael White]

Jamie,
I have inserted pictures...hopefully they will be clear enough.

This is an overlay of the RV-3 horizontal tail (green) and the RV-4 horizontal (white). Not telling you anything you don't already know...but illustrating the size difference. The RV-4 tail will put much more downforce on the tail, which will have a major effect on the handling of the 3.

Here is an overlay of the RV-3 vertical (blue) and RV-4 vertical (white). Again the 4 tail is larger, which you already knew. I imagine the 4 vertical will increase the yaw stability, but will require modifications to the fuselage structure to attach. The attachment points will need to be moved well forward of the RV-3 position, and the fuselage will need to be modified accordingly.

As a final thought...remember that the RV-4 empenage is not matched hole. It may be pre-punched, but you will still be doing a lot of pilot hole drilling and fitting.

Overall, I would not recommend putting the 4 tail on a 3. The increased downforce from the horizontal will have an adverse effect on the handling. To keep the handling the same, you would need to move the larger tail forward, and that is a major structural change you don't want to deal with...it would be much less work to just build the original 3 tail!

Warmest regards,

 

[runstrong92]

4 - empennage is not prepunched

I ordered the empennage for my 4 about a year and a half ago and it was not prepunched

 

[Jamie Aust]

Thanks for posting the pictures Michael,
If I do build a RV3, then it will be the correct 3 Emp. Looking at the forsale value of 3s they start at around $22K, so they dont seem to hold much value these days.
Anyway back to dreaming I guess.