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Fuselage Kit ready to crate

NorthernRV4

Well Known Member
I'm excited to say that my fuselage kit is now ready to go to crating. I put my deposit in 1yr ago almost exactly but I had planned for the long lead time anyway. Some home projects, including a basement finishing and workshop, have kept me too busy to really think about my -4 project in the last year but I'm excited to get it restarted in the new year.

A couple things. I've decided to go with electric flaps so I've ordered that kit. I also added the manual aileron trim kit as it was inexpensive. Since starting the project I've considered building my -4 as a Fast Back but now I'm at a decision point. I know there's some great info out there, including Axel Alvarez' documentation. Just not sure I'm committed to the Fast Back. I love the look but I know I'd be giving up visibility too. Just looking for other's thoughts on the matter. Those with direct experience would be appreciated.

Also, should I consider ordering anything else at this stage to ship with my fuselage kit? Seems I always remember something just after having a shipment sent from Vans.

Thanks all.
 
You have some time

I have to assume you haven't built a "slow build" RV in the past. The progress will likely be slow (based on mine and others experience), and you will have time to do almost anything imaginable that applies to an RV-4 up to the point of the "canoe rollover" when it comes off the jig. I chose to put electric flaps,elevator, and aileron trim on mine, so there was no need for the trim cable. I like the fastback as well, but built mine with the per plans bubble, and I'm glad I did. My wife is a picture taking machine, and the rear facing videos and pictures wouldn't be possible. She flew in my friends F1 Rocket and said she missed having the bubble visibility. I put rear seat vent ducting in similar to what was in the RV-8 plans (NACA duct in R/H wing bottom skin), and even though your in Canada, I would recommend it. I also have a NACA on each side below the cheeks for front airflow..the RV-4 in the sun gets hot. really aren't many changes to the kit to make at your stage. I also assume you have the wing kit because if you don't, the fuselage cant be built (Carry through bulkhead)..be really careful here when locating and spacing for the spar. I sure miss building, but I sure love flying my -4!
 
Thanks Bill. Yes, I've built the tail and wings already and I'm glad I did. It's been slow but I've learned so much more about the process than if I have gone pre-punched, at least that's what I keep telling myself when I question my sanity.

Thanks for the perspective on a rear seat photographer, that's one angle I hadn't considered :D I've been in the back seat of a friends -4 and it's pretty great for sure. I will continue with the kit as is and if I change my mind later I will worry about it then.

I also plan to put the NACA duct in the lower wing skin for ventilation. I also had the idea to plumb it in to a seat ventilation system to force fresh air up through the seat bottom and back for cooling. My car has that and how lovely would that be on a warm trip to Oshkosh in late July.

I'll turn my thoughts to building a fuselage jig. I know there are some plans out there and the builder manual has a sketch. Any thoughts that make that process easier would be appreciated.

Thanks in advance
Jim
 
The Jig and stuff

Jim, I used a fuselage jig that was originally built by Pat Hatch (on VAF) back in the early 90's, and mine was the 3rd -4 built on it. Pretty much the VANs specified wood type. The important factor if using a wood jig is dry,really dry lumber that wont warp during the build process. The concept is relatively simple, and the spacing of the ribs to match the plans is the important part, as is having it perfectly leveled. I even bonded the legs to the concrete floor with epoxy to keep it from moving. Adjustments are probably easiest on the wood jigs because they can be screwed too, cut and tweaked. Since I built mine during the 35MM and Polaroid film days, most of my pictures in my build manual have to be digitally photographed and compiled, but I can send you some that may clarify the jig configuration. I have attached one I did a while back for a different post regarding the wing carry through spacer. Keep in mind you will build 90% of the fuselage upside down and its easy to make mistakes!. I used a simple laser pointer through tooling holes and and sharpie marks to check alignment along the way, and all came out well. PM me with an Email and I can get additional ones to you. Also the routing of the rear seat air distribution I used may save you some thought getting the NACA in the wing to the back seat. Keep on building! Its worth it..took me 3-4 years over a 15 year span of life challenges and penny saving, but I never lost interest.
 

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Hi Bill

Can I impose on you to send me any pics you have of your fuselage jig?

I am about 1/3 through the wings andl already have the fuselage kit.

I was thinking about buying the lumber for the jib about 6 months in advance and letting it sit in my basement to stabilize?

Steve
 
Buy manufactured wood from a high end lumber yard. It is laminated and the jigs turn out straight with no warping. About 25% more cost but having a jig you can trust and repeat measurements on is invaluable

RV3B close
Flying J3 65 Cub regularly
 
Thanks for the input. If I use wood it will be manufactured wood for sure, I live on the East cost so moisture would be a problem otherwise. I was always planning to do a steel jig but I'll have to compare costs. Right now, I'd like to finalize the design. I know it's rather simple but accuracy is important.
 
One more thing,Wood vs Metal

Personally, unless going into production, I believe the wood is the best material.
The jig/fixture itself is a holding devise, and even if its slightly off, the clamping of the bulkheads to the jig crossmembers is adjustable with shims and such. You may want to screw additional supports to it, or cut interfering members away mid-build. The wood is easy to do adjustments/additions ,ect. Key is leveling and spacing the bulkheads and keeping check as you fit/drill/install the longerons and stringers and skins. Once you start, you cant take a partially built assembly back off easily and make changes to the fixture design. Also important is a very accurate "plug" the EXACT thickness of the wing spar stubs to be in the carry-through bulkhead. This will haunt you down the road during final assembly if its not done correctly.
 
RV-4 fuselage....

I've been in the back seat of a friends -4 and it's pretty great for sure. I will continue with the kit as is and if I change my mind later I will worry about it then.

I am REALLY happy to hear people are still building -4s! Mine took 6.5 years (I am a little bit of a perfectionist....) and worth every second! And (full disclosure: I am prejudice!) it might just be the best flying of all the RVs!

The full canopy, I think, looks better and the visibility is unmatched, including the -3 and -8 as there is nothing on the canopy to block the view. I would talk to rear seat passengers and get their opinions as that is a factor as well. There is a reason the F-16 is such a great airplane and part of that is visibility. There was also reason they went from the early P-51B/C models to the P-51D: full canopy and increased visibility. In a small, fast airplane you want all the visibility you can get! Hats off to the fastback builders.......;)



I also plan to put the NACA duct in the lower wing skin for ventilation. I also had the idea to plumb it in to a seat ventilation system to force fresh air up through the seat bottom and back for cooling.

Hmm....I have an NACA vent on the right wing plumbed to a large eyeball vent just to the right of the stick in the back seat and it will BLOW YOUR HAT OFF! Plumbing it to the seat itself seems a little complicated and extra work you might not need. With the front seat air flow and that vent I have never had complaints from my PIB, including the heat of Texas and Arizona.

I'll turn my thoughts to building a fuselage jig.

I think wood would be far superior to metal unless you are going into the business of building RV-4 fuselages. Wood would be easier to build and adjust. Be accurate with ALL measurements. And LOOK at the plans. I spent 30% of my building time looking at the plans and reading the construction manual. I know of one RV-4 that was built without the spar bulkhead being angled properly. When it came time to put the wings on, the rear spar was several inches above where it should have been.:eek::eek::eek: The fix: they pushed down on the wing until it lined up, drilled the holes and shoved the bolts in!!!:eek::eek::eek: Even with that (it was my first RV ride; didn't know this at the time), it flew pretty well for many years until it was wrecked for unrelated reasons..... Can you imagine the torsion on the spars....???:confused::confused::confused: Another witness to a great design that can absorb some builder "errors"....

Keep building! Every one of the 13,000 rivets driven is one closer to you having a flying airplane!
 
RV-4 fuselage fixture

Here are a couple pics of the jig I used. It was build by Pat hatch, and mine was the third RV-4 built on it. Worked great.
 

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RV-4 Fuselage jig.........

Here are a couple pics of the jig I used. It was build by Pat hatch, and mine was the third RV-4 built on it. Worked great.

Hey! That looks like mine!:D Boy, does THAT bring back some memories! Small, single car garage somewhere in the suburbs of Denver....!

My jig was given away after and I think three other RV-4s were built on it. No idea where it is now. Of course, that was "several" years ago!;)
 
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