Avistar Construction Questions
 

When i am building my ARF Avistar, the hinges say to use CA glue, other places i hvae heard you can epoxy them. Is epoxy okay?

Also, my fuel tank doesn't slide all the way up in the slot provided... what can i do about that?

any input would be very helpful!

thanks!


Oh yeah... i heard it's good to fiberglass the wing halves together....
How? i have all the stuff for it, where do i do it etc?

RE: Avistar Construction Questions
 

Not sure on the hinges I have always used CA.

If your fuel tank installation is like my Superstar, a little dish soap and water may help you get the stopper of your tank to go into the hole in the firewall. You may want to loosen the stopper screw on the tank and then tighten it when it is all of the way forward.

Fiberglass:
You can go anywhere from a half inch wide to as wide as I went here. I like to put masking tape about 1" outside of the 0.5 oz / yd glass cloth. This way you get a nice stepped down edge that you can sand to a feathered edge. I like the glass extended past the fuselage to prevent wing saddle wear. Unfortunately with an ARF you have to remove the covering. I'd wait for the first wing repair. If you are flying right side up the strength of the fiberglass is more valuable on the bottom of the wing than the top. You still need a good wing joint with 30 minute epoxy first.
http://www.rcuniverse.com/forum/thum...73/Lg17836.jpg

Large version.
http://www.rcuniverse.com/forum/upfi...73/Lg17836.jpg

RE: Avistar Construction Questions
 

No....the saddle that holds the fuel tank it's self is too small... thanks for the other info though!

What is CA and CA+ glue even???

RE: Avistar Construction Questions
 

Too small? By how much? Is it bare wood, or does it have plastic or rubber trim on the opening?

RE: Avistar Construction Questions
 

Use CA (Super Glue) for the hinges as those hinges are made to "wick" the CA down thru the hinge. Your local hobby shop should carry some thin CA. Get a minimal gap between the 2 surfaces you are hinging (be it ailerons, rudder or the elevator) then carefully deflect the surface downward and put 3-4 drops on each hinge. Turn the surface over (again, ailerons, rudder or elevator) and put 3-4 drops on each hinge again. Let the CA set for atleast 10 minutes, then you can move the surface up and down, to "free" it up. Also, a fine tip applicator helps avoid getting the CA all over the surface, as an example, I use an insulin syringe to get the drops right on the hinge itself. It should tell you somewhere in those instructions to use CA only, never epoxy the CA type hinge. Hope this helps ;)

RE: Avistar Construction Questions
 

As groundforce said, use CA! The instructions tell you to, which means your ARF came with CA hinges, epoxy will NOT hold them. By the way, get CA, not Superglue. The Superglue formulation is not the same as CA and while it may work, I don't trust it.

Many planes have a tank compartement that does not allow the tank to fit completely into the front section. Just push it in as far as it will go, don't force it or you can damage the stopper or fuel lines.

As long as the wings go together with a dihedral brace, and you use 30 minute epoxy to glue the halves together, fiberglassing is not necessary.
Dennis-

RE: Avistar Construction Questions
 

Thx guys, The fuel tank saddle is rubber coated....


Also, about the hinges, i did a test hinge with thin epoxy and as far as i'm concerned, if that hinge is coming out, it's going to take a whole bunch of balsa with it so i am not worried. I think CA would just be better because it's less messy and isn't going to 'join' the wing and aileron together and give it less movement.

RE: Avistar Construction Questions
 

Hi poorkid,

My Avistar ARF did not have any rubber coating saddle for the fuel
tank? It just had the forward bulkhead shaped for the tank supplied.
It was tight, but the tank slided all the way up to the firewall. Guess
maybe its a change?? The Rec./battery tray kind of butted up
against the bottom of tank..

On the hinges, I'm not sure on using epoxy? I used thin CA.. After
sliding half of the hinge into each side of which ever control surface
your working on, insure that the hinge does not move when joining
both together(i.e. slide more in on one side) make sure your control
surface is inline with the smallest gap possible, once satiisfied with
fit.. Hold the surface up, deflect the control surface with your fingers
then add 3 to 4 drops of CA, so as to "wick" the CA on to the hinge
and seating area... same for the other side.. My trainer said you
didn't have to do the inverted side, But I did..

On glassing the wings.. I was told if you insure of a good flat fit,
enough epoxy and holding together for the epoxy to completely
dry.. Glassing is not needed... But I added anyway..

RE: Avistar Construction Questions
 

I had a Hobbico plane with the rubber trim on the tank mount. At the risk of stating the obvious, make sure your control rods are above or below the tank in the round cut-outs. I remember thinking that my tank was not going to fit and I ended up with a very nice tight fit. I remember soaking the tank in hot water to soften it. I'm not sure if that worked or if I used the heat gun next to soften the rubber and the tank before it went in.
Dave

RE: Avistar Construction Questions
 

Inserting a pin in the middle of the hinge is a great way to be sure that the hinge is 1/2 in the aileron and 1/2 in the wing.

RE: Avistar Construction Questions
 

For added insurance pin the hinges once glued :D then you will sleep better at night knowing that it doesn't matter that the CA didn't wick in properly all the way as the pins act as "belt and braces" with the thin CA.

Good Luck,

Colin

RE: Avistar Construction Questions
 

raideron
Did you glass over the Monocote covering? I think that covering needs to be removed first to add the strength. I just had a wing fold because I didn't glass it. You can bet that I will following the advice next time.

BTW How well does the covering apply to epoxy? I will be doing this very soon.

dave

RE: Avistar Construction Questions
 

Poorkid,

Those hinges are specifically designed to be installed with THIN CA!

DON'T USE ANYTHING ELSE!

Also, there is a special technique to installing them. It's very easy, but it must be done right or the hinges could fail.

Here is a step-by-step "How to" for installing them. Please read the whole article before proceeding.

http://www.rcuniverse.com/magazine/a...TOKEN=55428108

RE: Avistar Construction Questions
 

I hope that you have your avistar flying. it is a great trainer that you can wring out pretty well.

RE: Avistar Construction Questions
 

My Avistar has been indestructible (knock on wood). Made it all the way through training, solo, and the inevitable hot-dogging that "happens" the first few times out at the field without the buddy cord.

Amazing!

Cant wait to get started on my Skyraider Mach II

RE: Avistar Construction Questions
 

Hey Dave,

Sorry for the delay.. No I trimmed the monokote off, than used epoxy to
apply the F.G. Then I painted with this auto paint I had sitting around..
I would guess monokote would stick pretty good, But?????????

RE: Avistar Construction Questions
 

I folded my Avistar wing (after months of flying with no apparent problems). Wing broke cleanly in the middle. My construction joint did not break--one of the end panels assembled by the manufacturer separated. And of course the wing joiner broke.

Question is, when I rebuild do I need the wing joiner? It is impossible to remove the original one that broke. My plan is to clean up the area where the wing broke, epoxy it, then fiberglass it--about 4 inches--enough to have the glass ride on the wing saddle of the fuse. If I do this, can I ignore the "wing joiner"? And, as someone has already asked will Monokote go back down on the glass? (I've already peeled it back to apply the glass).

Thanks

RE: Avistar Construction Questions
 

I would strongly suggest installing another wing joiner if at all possible

It not only adds strength it also sets the amount of dihedral for the wing.
I think your wing may fold again if you omit the joiner. You can make one out of lite ply

RE: Avistar Construction Questions
 

Forming a wing joiner isn't the problem. Removing the original joiner is the problem. It is well epoxied in and can't be removed. Afraid trying to drill it out will only result in "slipping" onto the balsa wood and destroying it.

I'm comtemplating rebuilding the wing with no dihedral anyhow.

And should the fiberglass run from trailing edge around leading edge and back to trailing edge or will just a strip on top and on bottom suffice. If I make it run aroud the leading and trailing edges, it will no longer fit in the wind saddle of the fuse.

RE: Avistar Construction Questions
 

Wing joiner on my Avistar was a metal rod. Have they changed it to a wood brace?

Andy

RE: Avistar Construction Questions
 

My Avistar with the wooden wing joiner is the ARF version. I think the select version has a metal rod as the joiner.

RE: Avistar Construction Questions
 

I did the same with my Superstar when the firewall left the plane in mid air and it ended up in a tree. I glued the wing back together and glassed the center section. It looked like a lot of work to try and repair the joiner, so I didn't. I used a single layer of 2 ounce/yard fabric (it might have been 3/4 oz.) and glassed the entire sheeted center section. That was 28 hard flights ago and it seems to be holding up fine. Takes some extra heat to get the Monokote to stick to the glass.

**********
I used one piece of fabric for the top and one on the bottom. They overlapped below the leading edge and on the trailing edge. The increase in thickness was very small and I have no problem with the wing fitting the saddle. A 2 oz fabric has a thickness of 0.004 inches. The fabric I used was a boat and tooling fabric from http://www.fiberglast.com and I used a Sig® Polyester Glass Resin

Dave

RE: Avistar Construction Questions
 

Thanks for the info davidinmi. I think I'll do something similar.