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1Beege

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Hey guys, been lurking on here for a couple years while getting an early 4 finished up that a friend started in the 80's I believe. Have a few bugs to work out, but it is finally in the air. I have tried searching and have found some of them but am hoping you could send me to a thread with a comprehensive list of changes from the older kits to now. Thank you!
 
Having SN 107, I too would enjoy seeing that comprehensive list. Assuming it does not exist, I can get it started...

The horizontal stab mounting changed at least three times. My plans show one way, my friends plans (~#325) show another, the most recent/current plans show a third way. IMO, each of the variations are an improvement on the previous.
 
The horizontal stab. attach, and longer gear legs are the only two that come to mind of any significance.
A couple of other minor ones were the availability of a cowl that accommodates a constant speed prop., and at the same time introduced the use of a filtered induction Airbox, and the introduction of an electric flaps option.
 
Oh... that reminds me. Not a 'plans change' but certainly an evolution/improvement in parts...
I recently swapped from an O-320 to an O-360 which meant that I replaced the cowling, cheeks, etc. My very old/original 320 cowl (with paint and fasteners) was a nice plump 24.7 lbs. The new/360 cowl from Van's (with thin paint & fasteners) was 13 lbs. A very welcome surprise!
 
The cowl changed from the original 12” spinner to a 13” spinner. They also changed the engine mount weldment brackets and beefed them up to prevent cracking
 
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1Beege said:
Is an early stab attach anything to be worried about? Thank you guys very much!
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My apologies, I only intended to point out plans changes but fear I may have sounded like I was raising an "issue" that was fixed. As far as I am aware, this change was only an improvement on the design (for maintenance, I would guess). I am not aware of any strength/failure issues with any of the -4 HS attachment 'styles'.
 
Yes, the stab attach was for better access to the attach hardware. The old design required a helper to crawl into the fuselage in order install and tighten the hardware.
IMHO, the only “must do“ mod is the engine mount weldments on the fuselage side of the firewall. Check to see if you have the thin split weldments or the thicker solid ones.
 
Newer tail kits include a 0.020" thickness skin for the rudder, where the older kits have 0.016".

edit: R-401-020 is that new skin, but it's not a straight-forward replacement especially if you've already painted.
 
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big change was to the steel longeron weldments. the old design was prone to cracking.
 
The changeover in the tail attach will require moving the top portion of the F-4 bulkhead, I believe. Might be best to attach the new horizontal the old way.
 
andoman said:
The changeover in the tail attach will require moving the top portion of the F-4 bulkhead, I believe. Might be best to attach the new horizontal the old way.
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Yes it does, in my case we are installing an RV8 tail on an RV4 (which has been done several times). Using the old way to attach was not great and I also felt the newer way was much stronger and worked with RV8 tail much better, so a bulkhead was ordered and being installed.
 
:) yep, similar arguments as for the e-flaps...
IIRC there was a slight weight advantage for the electrons flowing, and the possibility of trimming via a hat switch on the stick iso leaving the HOTAS.
 
I installed electric elevator and aileron trim as well as electric flaps. Against all grass roots basics, the HOTAS with all buttons on stick is great since no flap handle in PAX footwell and never need hands off stick or throttle for the essentials. If looking for other simple upgrades, put rear footwells in for backseater.
 
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