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!
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Early RV-4 differences
- Thread starter 1Beege
- Start date
YellerDaisy
Well Known Member
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 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.
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.
YellerDaisy
Well Known Member
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!
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!
YellerDaisy
Well Known Member
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'.
andoman
Well Known Member
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.
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.
vfrazier
Well Known Member
No. Not if built correctly.
and electric trim.... I recall converting from that heavy duty cable arrangement to the Mac trim servo.
andoman
Well Known Member
Here are links to a couple of threads with pix of the old and new plans ref the horizontal stab mount:
Post 9. https://vansairforce.net/threads/looking-for-early-rv-4-plans.156798/
Post 1. https://vansairforce.net/threads/rear-tail-doesnt-match-plans.216850/#post-1686787
Post 9. https://vansairforce.net/threads/looking-for-early-rv-4-plans.156798/
Post 1. https://vansairforce.net/threads/rear-tail-doesnt-match-plans.216850/#post-1686787
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.
Southern Pete
Well Known Member
But is electric trim an improvement?
yep, similar arguments as for the e-flaps...
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.
Three different types of fuel tanks.
The first rendition was the back baffel was reversed.
The second rendition, the rear baffel in present orientation.
The 3rd rendition was a prepunched skin. Not match hole tooling. Cannot be retrofitted to older renditions.
If I don't have this right someone can chime in and correct me.
The first rendition was the back baffel was reversed.
The second rendition, the rear baffel in present orientation.
The 3rd rendition was a prepunched skin. Not match hole tooling. Cannot be retrofitted to older renditions.
If I don't have this right someone can chime in and correct me.
Steve, I've never seen any baffles reversed, and that would have been a major change. The pre-punched skins were only for the 3/32 rivet holes and not the attach fasteners if I recall. Both the 4 and the 6 had this offered in later kits, which was a milestone compared to us legacy builders who had to lay out all the hole locations. I think a pre-punched kit tank could be adapted to a non punched airframe , but only if never drilled the the attach fasteners. Others that have done this may comment.
JimD,
Not sure but my old -4 had all the changes except "long legs" and it was built in 1989. Serial number 1969.
Daddyman
I wasn't sure about about the prepunched attach points on the 4. I built a prepunched 6 tank to replace a damaged tanka couple of years ago. It had the attach points prepunched but the kit was originally designed that way.
As far as the RV4 rear baffels facing in, the very first 4's were that way.
As far as the RV4 rear baffels facing in, the very first 4's were that way.
andoman
Well Known Member
Jim D,
I’m not sure of the exact date the changes were made. Early-mid ‘80s I believe. And they changed twice: Light weldment with no split and finally thicker weldment. It’s less about when the plane was built and more about when the kit was shipped.
Best to look at all the great -4’s that come up for sale. If you find one with the old weldments and they aren’t cracked there are a couple of relatively easy mods that add doublers. If you find the right plane don’t let the old style weldments scare you away if they are still intact.
Lots of discussion in this thread. See post #42:
I’m not sure of the exact date the changes were made. Early-mid ‘80s I believe. And they changed twice: Light weldment with no split and finally thicker weldment. It’s less about when the plane was built and more about when the kit was shipped.
Best to look at all the great -4’s that come up for sale. If you find one with the old weldments and they aren’t cracked there are a couple of relatively easy mods that add doublers. If you find the right plane don’t let the old style weldments scare you away if they are still intact.
Lots of discussion in this thread. See post #42:
Shawn's -4 re-build
Hi all In a couple of other threads, I started asking questions about RV-4's before I bought one, then found one that was complete and flying, with a 180 hp in it, which was appealing. It was not so nice that I would be afraid to take things apart and start making changes. I need to learn about...
vansairforce.net
Ricksrv4
Member
Builder 526, tank baffle flange facing inward, requires using closed end pull rivets. Aileron torque tubes diameter increased eliminating the need for a guide in the rib pass through for support.
Not sure when changes were made, would need to compare the 1983 plans to the 2000 plans, dates for changes are listed in the foot notes.
Not sure when changes were made, would need to compare the 1983 plans to the 2000 plans, dates for changes are listed in the foot notes.
Norman CYYJ
Well Known Member
My older 4 uses a transmission oil cooler mounted above the engine, surprisingly it works very well.
FlyingDutchman257
Active Member
What effect did that have on the empty W&B?
Built, flew RV-4 for 11 yrs early RV-4. There was a book that compiled all the RViator's. Van's monthly news letter. It was something like 20 yrs or 25 yrs of RViator. It will be a wealth of information. (RESPECT Vne. If you are over 10,000 feet, point it nose down, fast descent, Vne is TRUE not indicated. All RV's can flutter if you exceed limits.)
Depending on year kit was produced may determine kind of fiberglass, cowl, fairings, vinyl-ester (no core), gel coat. Van updated glass parts for all RV's.
There was the short gear and later longer gear versions of the RV-4. New engine mount for longer gear.
There were old wheel pants, mid-gen two piece, than latest greatest bigger two piece (now standard for +20 yrs).
There was an old air scoop and unfiltered airbox. The FAB (Filtered Air Box) came next and standard for +20yrs. Id unfiltered change that ASAP.
Second for newer RV's RV-8 and on, if you are registered with Van's, with serial number/customer number, you can log in, look for all the service bulletins, service letters, plans updates. See if you can look up this data, give Van's a call. I am sure RV-3/RV-4/RV-6 have historical data you can look up with Van's.
Other than that there is a lot in common with RV-6 and later RV's.
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YellerDaisy
Well Known Member
Effectively none... because... that engine swap included the larger engine, lighter cowl, switch to lithium battery, along with a load of other things (firewall changes, new/larger oil cooler, new exhaust, new carb, new prop extension, and on and on) but the same prop/spinner (though the backplate had to be replaced for the larger prop bolts). Empty weight with O-320 was 970 lbs, empty with O-360 was 968 lbs. CG with normal load moved one tenth of an inch aft.
