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new builder, need advice....

tom gort

Member
Hello to all, I am a new builder of a -4. I started about 4 months ago, and am about halfway through the empennage. I have a few questions for anyone out there who can provide some advice since I have never done this before....First of all, should I go with manual or electric trim on the elevator? I am planning on keeping the acft as simple as possible, however I would like to hear any opinions on the pros and cons of both. Also, I will be ordering the wing kit shortly and would like to know if the pre-made spars are worth the cost. I enjoy the building so the thought of doing these myself is not that daunting, but it would be nice to hear from someone who has put one of these together if the time/difficulty involved makes it worthwhile to just get the completed assembly. Thanks in advance for any help, and if there are any other -4 builders in the seattle/tacoma area I would like to hear from you. (I am in Puyallup).
 
Tom,
When I started my -4's build 10 years ago I too wanted to keep it simple. I installed the manual trim and am glad I did. It is easy to operate and is lighter and cheaper than the powered trim set up. I also built Van's standard spar and would do it again if I decide to build another plane. It took longer to assemble and didn't look as nice as the anodized unit but you can't see it anyway once it is installed. The money I saved went toward all the other stuff I needed for the panel and for filling up the tanks.

Alan
RV-4 N7028K
 
Welcome, Tom....

....to VAF. I have a buddy who's building his fourth airplane, an RV-3. I mentioned to him that he could buy quickbuild wings and save a bunch of time. His reply was that he really enjoyed building and wasn't at all interested in NOT building the wings.

If you're in that frame of mind, build your spars. If you'd like to save time and have neat, anodized spars, go with them pre-built.....it's your call, after all:)

Best,
 
Thanks for the input, I will probably build the spar myself. Maybe I am the exception here, but I seem to have more time than money....plus I will end up with an airplane that I completely built myself. This was one of the (many) reasons I chose to go with the -4, I enjoy the challenge of building so I am looking forward to this next step.
 
Manual trim v electric

I have to disagree on the weight issue on the manual trim mentioned above. Yes manual will be lighter if you dont count in the weight of the cable that has to run the length of the aeroplane. I have electric on my 9 and 4 and its simple to use.

I would go with the phlosigon spars if thats what you are asking, definately corrosion proofed and built right.
 
Phlogiston spars

Will help the resale value. Most people buying a used Vans do their homework. And people love the electric trim; the weigh difference is not a factor. JMO.
 
I don't know what kind of anodizing Vans spars have, but "normal" anodizing using sulphuric acid most certainly will reduce fatigue life a whole lot.

This has been discussed extensively. It has been determined that the "plus" benefits of the anodized spar FAR outweigh the "negative".
 
Build your own!

My two cents:

I built my own spars and enjoyed the challenge and the savings.

If you radius all the edges, etch and Alodine your non-alclad parts and epoxy primer everything it will be as corrosion resistant as anodizing.
The riviting process is simple and easy to get perfect results.

I also have 15 years and 1100 hours of trouble free service from the elctric trim. I recently added the Infinity stick grip and having trim on the stick is delux.
 
This has been discussed extensively. It has been determined that the "plus" benefits of the anodized spar FAR outweigh the "negative".

Determined by who? That helicopter I linked to was "determined" by judges to become Grand Champion at Osh. The anodizing on those rods didn't exactly outweigh the negative.
 
Determined by who? That helicopter I linked to was "determined" by judges to become Grand Champion at Osh. The anodizing on those rods didn't exactly outweigh the negative.

Van's engineering department!
 
Tom, I wanted mine simple too, but several builders convinced me to go with electric trim and electric flaps. I've been told by several that said the electric trim is actually lighter especially where you need it in the tail on a 4. You might find this short thread helpful when trying to decide on the options including the trim on the elevator:

http://www.vansairforce.com/community/showthread.php?t=51592

Despite the popularity of the phlogiston spars, I still opted to build my own here. Even though they really do look nice, I don?t mind spending a extra few days building my own.
 
80 years .... at 150 hrs per year

Determined by who? That helicopter I linked to was "determined" by judges to become Grand Champion at Osh. The anodizing on those rods didn't exactly outweigh the negative.

Mel knows what he is talking about...

http://www.matronics.com/rv-list/hovan/tips/AlAnDef.html

excerpt:
Van wrote an article in the Dec 1991 issue of "The RVator" that addressed the issue of Anodized spars and the affect on fatigue strength. The issue is what does anodizing do to the service life of the spars? His conclusion was that anodizing offers more than double the corrosion resistance of priming. However, it also reduces the fatigue life by up to 50%. The normal fatigue life was computed to be 24,000 hours on regular aerobatic use so the anodized life would be 12,000 hours. That would be 80 yrs at 150 hrs/yr. Also, these are conservative numbers. If you get corrosion in a spar it also lowers the service life (and maybe yours also) so anodizing them is a good tradeoff.​
 
phlogiston spar

Lycosaurus, that was the link I was fixin' to post next as well, but you retrieved it before me. Thanks for getting it.

I think that sums it up quite nicely in that little paragraph. I suppose if one has the money, not as much in time, go ahead and get the phologiston spar. 150 hours a year for 80 years is a lot of flying time before one would start to consider spar fatigue, and I imagine corrosion would have got to the primed spars long before then.
 
There's absolutely no problem building you own spars. They're not difficult, but there's no reason to be afraid of the Flogiston spars either.
They've been proven on thousands of airplanes.
 
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Mel knows what he is talking about...

http://www.matronics.com/rv-list/hovan/tips/AlAnDef.html

excerpt:
Van wrote an article in the Dec 1991 issue of "The RVator" that addressed the issue of Anodized spars and the affect on fatigue strength. The issue is what does anodizing do to the service life of the spars? His conclusion was that anodizing offers more than double the corrosion resistance of priming. However, it also reduces the fatigue life by up to 50%. The normal fatigue life was computed to be 24,000 hours on regular aerobatic use so the anodized life would be 12,000 hours. That would be 80 yrs at 150 hrs/yr. Also, these are conservative numbers. If you get corrosion in a spar it also lowers the service life (and maybe yours also) so anodizing them is a good tradeoff.​

Thanks. Anodizing can reduce fatigue life by much more than 50% (as well as much less), and there is no way to determine the mean reduction for a component without testing it, too many uncertainties. 50% could be a conservative educated guess, but not necessarily so. There are ways of anodizing without any (known) reduction in fatigue life as well, it is a bit strange that a critical component like the wing spar haven't been anodized by those methods.

I am not saying that the anodized spars are bad, I'm only saying I don't understand the reason for anodizing all things considered. And I certainly don't see how the positive FAR outweigh the negative.
 
The toughest thing about manual trim is how and where to put the lever. Space is pretty tight in the -4. Regarding the spar, just build it yourself. It's absolutely no big thing at all and pretty satisfying when finished.
 
Nevermind. It's like I skipped a page.

L.Adamson --- 15 years with the anodized spar. RV6A
 
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Wow, I didnt think I would get this many responses, thanks to everyone for your input! I am beginning to see that there are definately a lot of different opinions out there on the spar question. I suppose either way I go I won't outlive the service life....so I think I will do them myself. Good to hear they are not that difficult, I was a little intimidated at first because I have read and re-read the wing section and it seems like there is absolutely no room for mistakes on this one...I'll just take it slow and make sure I don't end up building a twin set (hopefully!) By the way, what is the best method for you guys that have built your own did you use on the no. 6 rivets? I saw a couple of possibilities in the build manual, but if there a method you would definately NOT recommend please let me know, much appreciated. tom
 
On the floor with a c-frame and a B.F.H. (big friggin' hammer). I suspect pneumatic squeezer is easier, but hammers are cheap.
 
Trim

I have an RV-4 with manual trim, and an RV-3 with electric trim. Manual trim for me by a wide margin.

Barney, in Memphis
 
On the floor with a c-frame and a B.F.H. (big friggin' hammer). I suspect pneumatic squeezer is easier, but hammers are cheap.

That's the way I did mine. It took about 3 hours/spar, and I came away sweating like a blacksmith, but rarely has there been end-of-job satisfaction like that one was. If I were doing it again, I'd do it the same way.
 
No wrong way to do it

Van's has a pneumatic rivet squeezer they rent for fabricating your own wing spars (needed for the big rivets). That is what I did. Anodized spars are nice too so I'm not advocating either. Assembling the spars is one of the few positive sweat equity options to save money, and that was the driver for my decision.

Manual vs. electric trim; no wrong choices on this one either. My ship is a simple, light weight, wood prop sport plane. My goal has always been fun and easy to maintain, with simple systems. Yes, I have a single ?do it all? glass panel unit. Originally I installed a quadrant with manual trim lever sandwiched behind. It worked very well, but there was play in the combined throttle and mixture linkages. The thick green cables are stiff and difficult to route, and the amount of throw in the throttle lever wouldn?t hit both stops on the carb (second hole on the arm). I saw photos of Tony Spicer's 3 and decided to go that route instead. This facilitated using the manual trim lever as originally designed. I agree with the RV herd that a quadrant is nostalgic and sexy compared to knobs, but they are way easier to install, virtually no play in the linkage, lower parts count, less expensive. Also, the cables are thinner and much more flexible, and certified to boot. A collateral benefit is increased room for my long legs on the side where the quadrant formerly resided. I think electric trim is a great option too, and the big green cable is heavy. You can hold off on both of these decisions for a long time, so keep your ?research? paddle in the water and enjoy the build. You will spend many wonderful hours hashing out these, and many more decisions, in your mind. That is the essence of the fun; planning and customizing YOUR airplane.



 
Van's has a pneumatic rivet squeezer they rent for fabricating your own wing spars (needed for the big rivets).

As does Bob Avery of Avery tool. Seen Bob a few weeks ago, and he says it's nearly always avaiilable. Bob also rents out electronic scales for the weighing of your plane.
 
If electric trim, get the rate reducer

I have owned both manual and electric trim RV-4s. My current RV-4 has the electric elevator trim. The big difference this time is I also installed a rate reducer module on the MAC trim system which greatly slows down the trim rate to the elevator. In the past on both my -4s and my -6 and -8 I had the standard setup and a little bump of trim could be excessive. Now, I have no problems at all and really like my electric trim setup on my stick 'cooly hat.'

As for flaps, if you want to have someone in the back seat, get electric flaps. They are quite easy to install and/or retrofit and have been without problem. Love em!

Lastly, the 'factory' spar is excellent and does help the resale of any VANs aircraft. Remember, there has NEVER been a spar failure of an RV-4, so I would not worry about that in this particualr aircraft...the best of the VAN's fleet! (Flame bait!:eek:)

Tailwinds
 
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