Upgrading Avistar engine
 

Was at base hobby shop today and wound up being forced to buy Super Tigre GS-40 ring. This engine has been in the case forever, and I got a pretty good deal on it. It's the older version with the non-silent muffler. Would have prefered GS-45 but this should haul the Avistar around with a little more uumph than the old LA. Should be no problem to mount, looks like exact match size wize, but is a little heavier. Was looking for some hints/suggestions from any of you that have up-engined your Avistars... and please, please don't tell me I should have gotten an FX-46, I hear that all the time at the field. S-T was a LOT less expensive! I'll post some pics as soon as I get home and get the camera out....

RE: Upgrading Avistar engine
 

Of course I'v 'way biased, but your SuperTigre GS-40 will fly your Hobbico Avistar very nicely. You'll notice quite a bit of power increase over the .40 LA. The main thing with 'Tigres is to bet them well broken-in, and to adjust then correctly. The instruction book and the web page are great resources:

http://www.supertigre.com/faq/product-faq.html

RE: Upgrading Avistar engine
 

What exactly are you looking for????

Mount the engine rebalance and fly.

maybe try an 11x5 and or 10x6 prop??

RE: Upgrading Avistar engine
 

Is an OS A3 plug considered a long plug?

RE: Upgrading Avistar engine
 

I have an Avistar and I am very happy with it. I have a OS .46fx on it and just had to move the battery aft of the servo compartment to balance it. One day last summer there was a guy flying his Avistar with the stock OS .40la and I got to see the comparison. His floated a little more but seemed to take forever to get up speed to take off. Our field is grass and is a little bumpy, the extra power really helps me. After he saw mine fly he was thinking of up grading his motor to something with a little more power. I originally I almost bought a Thunder Tiger Pro .46 but went with the OS because it was lighter. I also like the .46 because I like to run mine rich and not care if I loose a little power. The reason I bought the OS .46fx over the OS .40fx is because thier wasn't much weight or cost differences. I always have in the back of my mind not to dive it at fully power and snap the wings off. I read alot of posts saying that the .46 is over kill on the Avistar but the Sig web site packages the Avistar with an Irving .46 motor.

Don't feel bad that you didn't get the OS engine, If that Super Tiger has more power you will be happy! I almost bought an engine yesterday just because it was a deal.

Chris

RE: Upgrading Avistar engine
 

I have a MDS .48 in my avistar and it weighs a lot more. What I did was move my battery behind the servos in a closed area right under the ele. and rudder pushrods. It is still a little nose heavy but better then tail heavy.

I will try and get picks.

RE: Upgrading Avistar engine
 

The battery is in the far back. I used a few layers of duct tape which works ok. If you use duck tape it could slide back so tape the wires together so they do not pull apart. The best would be double sided foam tape that is fairly thick so it will stick to the pushrod tubes.

RE: Upgrading Avistar engine
 

Cessna I would advise against taping anything to the tubes. You will put pressure on them and may cause some binding and trim changes. Just be sure the pack is securely mounted. Maybe a wire tie can be used to tie it down.

Mark Shuman

RE: Upgrading Avistar engine
 

I mis spoke a little, I have it taped to the bottom but it is not touching the tubes. I think it would be better if you made that area a little smaller and a tighter fit so the pack is not rattiling as much by maybe having support the tubes up. But now that you tell me it can be bad you might just want to tape or glue down rubber padding to keep it from rattling and it will be more secure scence it is glued not taped.

RE: Upgrading Avistar engine
 

Well, had it in for a while. Having some problems getting it to run right, would run on prime, rich, then lean out, then quit. Was thinking that maybee the needle valve is too high, it's about 1/4 inch higher than the LA's was, everything else seems OK. Fuel lines not kinked, etc. I set up needle valve as per S-T instruction book, 3 turns open, didn't play with low speed needle. Will re-mount this afternoon after flying, at field, and see if I can't drum up some more helpfull suggestions...

RE: Upgrading Avistar engine
 

You will find that your plane will not fall out of a lot of maneuvers compared to the LA. You made a good purchase.

RE: Upgrading Avistar engine
 

I have to needle valve in the same place but yours looks like it sticks out more on the side. The only time mine ran lean was when the fuel tank was not padded. The the valve in the engine could be blocked maybe?

RE: Upgrading Avistar engine
 

I get fuel all the way up to the engine, and can -sort- of force it through needle valve. I should pull carb slide and check passages, may be some mfr. debris in one of them, who knows. I really need to borrow electric starter to do this sort of stuff, flipping with chicken stick gets old fast. Thing with Avistar is it's impossible to pad tank, it sits very tightly in formers with no room to pad. I suppose I could sand the formers back enough to get some foam in there, but I don't have any problems with the LA and I'm sure that thing vibrates more than the S-T is going to.

Andy

RE: Upgrading Avistar engine
 

It is not impossible but a real pain in the a--. You have to tape it so it slides in there with out riping. Make sure it is maybe 1/8 foam of some sort. You just need it on the top and the side.

RE: Upgrading Avistar engine
 

I tried balancing plane with S-T in the other day... seems like moving the battery behind the pushrods isn't going to be enough! It balances right on the fwd. edge of the CG range. How did you get your battery under the pushrods anyway? dosen't look like there's enough room to slide it in.... thought about a hatch.

RE: Upgrading Avistar engine
 

How many cells and is your battery flat or stacked? You need to fit it in at an angle and use plyers to slide it under. The hardest part of the whole kit :)

RE: Upgrading Avistar engine
 

A regular at the field has an Avistar with a 4-stroke in the nose. He had to cut a hatch and mount his battery as far back in the fuse. as the wires would allow. My battery pack is square, I guess I could spring the cash and buy a flat one. Would slide under pushrods a lot easier. I'm going to build a test stand next week and borrow an electric starter, will get that S-T to run or else!

RE: Upgrading Avistar engine
 

Ya mine is still a little nose heavy but it flies ok. I might think of making a hatch to put it in the next rib section.