RE: Fixing Avistar Horizontal Stab
 

I tried to get rid of the fuel with the windex and it did get most of it off. The parts that I was having trouble sticking were where the old covering was wrinkled and I couldn't push down on the new stuff to touch the old to get it to stick without doing damage. I tried ironing the old stuff to stiffen it up but that didn't work so I sealed the edges with scotch tape which seems to be ok. I'm going to keep an eye on it after the first flights and if it decides to come loose I'll try the CA fix.

Thanks!

Anyone going to Scobee field this weekend and want to help me re-tune my engine? :)

RE: Fixing Avistar Horizontal Stab
 

It will require more elevator to rotate for takeoff IF the CG is correct. If the CG is wrong all bets are off. Check and correct the CG if needed. Aft gear movement and tail repair will most likely cause a CG shift to the rear - not good if too much.

RE: Fixing Avistar Horizontal Stab
 

Did you re-check the balance on the plane?

RE: Fixing Avistar Horizontal Stab
 

I haven't re-checked the CG yet. I'll check it when I get home tonight and try to measure how far back from the LE it is. Anyone know where it's supposed to be on the Avistar? I can't remember.

How off would be too off and what would I do to fix it? I'm guessing adding weight to the front but how?

RE: Fixing Avistar Horizontal Stab
 

Balance it on the main spar

RE: Fixing Avistar Horizontal Stab
 

3 1/4" back from the LE is where the Cg is supposed to be, if its 3 1/2 it will be fine and will lift off a little quicker, but I wouldn't go much more than 3 1/2"

RE: Fixing Avistar Horizontal Stab
 

Quote from the manual. . . . .

Use a felt tip pen or a narrow strip of tape to
accurately mark the balance point on the bottom of
the wing near both sides of the fuselage. The
balance point (CG) on the Avistar 40 is located
3-1/4" (83mm) back from the leading edge.
The point at which your model should balance for
your first flights. Later, you may experiment by
shifting the balance up to 5/16" (8mm) forward or
back to change the flying characteristics.

Moving the balance forward may improve the smoothness
and arrow-like tracking, but it may require more
speed for takeoff and make it more difficult to slow
down for landing.

Moving the balance aft makes the plane more agile
with a lighter and snappier feel.

Please start at the location we recommend and do
not at any time balance your model outside the
recommended range

RE: Fixing Avistar Horizontal Stab
 

You might try cleaning with alcohol after the initial windex wipe down if you want the patch covering to stick better. It has worked better for my repair patch jobs. For balance adjustment move the battery forward - it might fit under the fuel tank if needed without using additional weight. I have done that on a couple of planes.

RE: Fixing Avistar Horizontal Stab
 

I guess my memory aint too bad yet huh w8ye. Actually, I've put three of these together in the last year and all of them required me to put the battery aft of the servo's to get the Cg in the right place. One of them even required adding some weight to the tail, but this was probably because I moved the .46 magnum a little foward and used a lot of epoxy when I took the dihedral out of the wing.

RE: Fixing Avistar Horizontal Stab
 

You did good Hugger.

I enjoy that you enjoy the Avistar. It is a good plane

RE: Fixing Avistar Horizontal Stab
 

Sure is a good plane!;) I teach a quite a few people to fly Rc, and these things are about the most agile trainers I've flown. I Got distracted the other day while letting a kid fly one on the buddy box. He had it inverted, headed straight down Wot about 30' high when I realized he was in trouble. Any other plane would have bit the dust but I was able to snap it around and pull it out about 5 feet shy of planting it!

RE: Fixing Avistar Horizontal Stab
 

That's good that you use your planes to help others learn to fly

RE: Fixing Avistar Horizontal Stab
 

I roughly checked the CG last night with a little help from my wife. We put our fingertips under the wing on either end about 2-3 inches back from the LE and it balanced pretty good. This was with about a half tank of fuel in it though so I'm going to empty it tonight and check it at 3 1/2" back per the manual. Hopefully I won't have to add any weight but we'll see.

Thanks for all the help! Really appreciate it.

RE: Fixing Avistar Horizontal Stab
 

be sure and do you CG balance close to the fuselage and not at the wing tips

RE: Fixing Avistar Horizontal Stab
 

Will do. It was difficult last night because I had to hold my 2 month old while picking up the plane. :)

Just curious, what is the reasoning behind measuring near the fuselage vs the wing tips?

RE: Fixing Avistar Horizontal Stab
 

On the stock original Avistar it is not critical but on an Avistar that has anhedral rather than dihedral it would make a tremendous difference.

Another example would be an (as original) low wing plane like a Kaos. You have to balance them up side down so more mass is below your balancing device pivot point. If you do it at the wing tips, there is less mass below your pivot point.

THE END RESULT by not balancing close to the fuselage and not having more mass below the pivot point would be over sensitivity of the balancing process and the multiplication of error. You would be trying to add nose weight but then you need tail weight. You can never find the correct spot. The plane will always seem out of balance.

It is best to get yourself accustomed to balancing up close to the fuselage for these reasons.

If you want a real aerobatic Avistar you need to try one with the dihedral reversed with the wings drooping. Looks weird but they are better balanced for the full realm of arobatics.

RE: Fixing Avistar Horizontal Stab
 

Sorry for the mistake, wrong thread.

RE: Fixing Avistar Horizontal Stab
 

After the repair's I would re- balance the plane again before flying it. JMO.

RE: Fixing Avistar Horizontal Stab
 

I made an inexpensive little jig for checking my Cg. Its just a scrap piece of 2x6 with two oversized kinder-garten type pencils dropped into two holes drilled near the sides. Just enough room for the fusalage of a .40 size plane to fit between with an inch or so to spare. Round off the edges of the erasers a little and they work pretty good for resting the wings on without damaging the covering.

RE: Fixing Avistar Horizontal Stab
 

Well I emptied the fuel tank last night and marked the wings 3 1/4" behind the LE and it balanced just a little nose heavy. With a full tank it will be great. I'm guessing it was very nose-heavy before and I never noticed a problem. Going to try to get out to the field this weekend to tune the engine and get it back up in the air. I'll let you know how it turns out.

Thanks for all the help!

RE: Fixing Avistar Horizontal Stab
 

Mine flew best when the stab was absolutely level checking the CG at 3.25. Landings are easier as well.

RE: Fixing Avistar Horizontal Stab
 

Sounds as though it is ready to go

RE: Fixing Avistar Horizontal Stab
 

[font="Times New Roman"]Should fly just fine like that, especially if you are used to landing warbirds,but like Tom Nied said, it will land slower and be a little more responsive if you can move the Cg a little farther back. Keep us posted!

RE: Fixing Avistar Horizontal Stab
 

I'm just finishing my assembly of my second Avistar and have just completed the balancing. My battery ended up 6.25 behind the rear wing dowel former. Just behind former F5. By getting the battery back there, I only had to add .77 ounce at the tail to bring it to balance. I'm using a GMS 47. If I ever would do this again, I'd be tempted to mount the rudder and elevator servos on the outside of the rear fuselage. Or maybe even better, shorten the nose portion. But it comes down to, "hey TOM!, It's just an Avistar!". Have fun with yours, They're meant to be fun.

RE: Fixing Avistar Horizontal Stab
 

On the two I've got with .40 La's on them, I ended up shoving some foam into the fusalage, aft of the servo tray to make a nest for the battery and shoved the battery back into the hole. Using a square futaba 600mah battery. Had to trim a little off the header that the rudder and elevator push rods run thru so the battery could slip in and out, but this got my Cg back where I wanted it without adding anymore weight. Its working pretty good so far. The one I've got with a Magnum .46 still required some weight on the tail.

RE: Fixing Avistar Horizontal Stab
 

Yeah if I had a square pack rather than a flat pack I think I could have gotten the battery further back in the fuselage, but I can't complain with only the addition of .77 ounces to the tail to bring it into balance. I did convert the landing gear to a conventional tail dragger and lost the weight of the nose wheel, which I think helped. I know one thing, if I didn't push the battery that far back, I would have had to add 3 ounces of weight to the tail to bring it into balance. So I feel I did good. With a little surgery it would not be too bad moving the firewall (former F1) back, and it would be easier to bring the Avistar into balance. But whatever it takes, it's worth it.

RE: Fixing Avistar Horizontal Stab
 

Been thinking about making one of mine a tail dragger. What did you do for steering on the tail wheel? Seperate pushrod, or did you tie it in to the rudder?

RE: Fixing Avistar Horizontal Stab
 

Tie it into rudder makes life much more simple

RE: Fixing Avistar Horizontal Stab
 

Before gluing the Rudder on, I glued a torque rod I made from 1/6 music wire to the Rudder. Much like what you have at the ailerons except the arms are in line with each other. So that transfers the rotational movement of the Rudder down through a small semi-circular hole at the elevator's leading edge in the center. That hole allows the torque rod to pass through. It's long enough to come just to the bottom of the fuselage. I used a Sullivan Tail Wheel Bracket http://www3.towerhobbies.com/cgi-bin...&P=SM&I=LXFV47 mounted to a block I glued behind a hatch cover I made in the rear fuselage bottom. I knew I'd probably would have to add a little tail weight, so this hatch has dual purpose. Tied the torque rod and the Tail Wheel Spring wire they give you together with just a piece of fuel tubing. So there's no direct mounting of the tail wheel to the rudder, so in a jarring landing, the rudder hinges don't get a jolt. I think you could almost get by with a "free wheeling" tail wheel, but that's not the biggest rudder to have much authority. I figured some steering would be fine and am not worried about precise steering. Haven't flown it yet, but it looks sound.

RE: Fixing Avistar Horizontal Stab
 

Well I just got back from the field and what a beautiful day! Took about 2 hours of messing around with different people at the field to get the engine tuned but finally dialed it in. I thought since it sat for a year unused some gunk had built up in there but luckily not. On the first flight it wanted to climb and climb even when all the down trim was exhausted so we landed it, tightened the clevis and went back up. Flew great! Brought it around for a landing after flying the pattern for a while and was planning on having a slow, test landing about 20 yards up but when I got over the end of the runway the engine died! I dove a little quickly and made a pretty good landing, if I do say so myself. :) I wanted to get another flight in but batteries were getting low, it was crowded out there and getting later in the day. I'm going to try and go again tomorrow when there aren't so many people there.

RE: Fixing Avistar Horizontal Stab
 

Cool! The nice thing about an Avistar and what I remember from my first is that you can get a rhythm going. Takeoff, fly around, land, fill the tank and repeat. Do that about 8 times and you've had a great day at the flying field. Socializing is great but the Avistar can be great fun and a real workhorse when it comes to gaining flight time. I'm looking forward to sport flying mine. Unfortunately the weather up here in Chicagoland is cold and a recent covering of snow, so its going to be awhile before I'll get out. Happily I can report my second Avistar is finished and ready to go.

RE: Fixing Avistar Horizontal Stab
 

I might just try a free wheeling tail wheel first. The Avistar that has the .46 on it also has a custom rudder. I made it about 100% larger than the original so it would Knife edge better. It does this excellent now so it might steer on the ground ok with a free wheel.

RE: Fixing Avistar Horizontal Stab
 

I lived in the south at one time and I remember how crowded the flying field was on Sundays on a pretty winter day.

RE: Fixing Avistar Horizontal Stab
 

The last time I flew (late November '08) it was 47 degrees. Think that's about my lowest limit for comfort while flying. As you can imagine, I've been flying RealFlight lately.

RE: Fixing Avistar Horizontal Stab
 

I cheated the other day. It was about 33 degrees out, dead calm, and no one else around, so I got back in the truck and put the Tx antenna out the window! Took off, flew, landed, refueled and repeat, all warm and cozy! No danger of interference where I fly, but I wouldn't reccomend this anyone!(one of those "do as I say, not as I do" things!):D

RE: Fixing Avistar Horizontal Stab
 

Ha! That's great. Well it makes sense to hop in the trunk to stay warm. Think I might just venture out this Wednesday just see what the field looks like these days. Going to make one more check of everything on my Avistar and then store it away tagged Flight worthy.

RE: Fixing Avistar Horizontal Stab
 

Why put it away? There's bound to be some good flying days in the weeks ahead!

RE: Fixing Avistar Horizontal Stab
 

We have at least a 4" cover of snow here. Temps this morning are only 23. I need warmer weather than that to enjoy RC flying. But being ready is a good idea for those fluke weather OK days that might come along. Your high temps today are approaching what I would consider my minimum. But you're right, we'll see what happens in the next few weeks. Might be a good time to get some pics of mine while its still whole. Ha!

RE: Fixing Avistar Horizontal Stab
 

Went flying again yesterday and had a GREAT first flight. Really enjoyed getting it up in the air and had the whole field to myself. :) Then on the second flight the engine suddenly quit and had to deadstick it in. I noticed the engine wouldn't turn through the compression stroke at all so I popped the top off and there were metal shavings on the piston. It looks like the bearing wore out so I have to replace them before playing again. Hopefully I can get it back up ASAP as it felt so great to be back in the action! :)

RE: Fixing Avistar Horizontal Stab
 

Groovin to the thought. Wish I could come home from the field smelling like castor oil.