Ok, got my CG machine. Nice little tool, seems to take very accurate measurements. Here is a picture of the airplane with the 3oz weight on the back set up for exactly 3.5":



This doesn't add up, when I did it on my finger tips it was dead level now on the balance which I trust a bit more, it's nose down, yet it flew nose up.

I did find that my ailerons where a little bit up when I took out a straight edge like adstott suggested so I can only guess that that is the problem.

I also got a incidence meter so I'll check all of those values later when I get time.

So what do you guys think, little nose heavy now? Should I add even more weight?

Also, there is a tiny little bit of fuel in the tank, the stuff my clunk can't reach when draining the fuel tank, is that going to make much difference?

schu

Yes,
that is too nose heavy. You still need to add weight to the tail of the plane. Don't worry about the little bit of fuel left in the tank. As I said earlier, don't worry about the incidence. You're main problem right now is that the plane just isn't balanced properly yet.

It flew nose up, and the balance was as shown in the picture?

I'm having a tough time with that. Even if the balance and aileron up-trim caused you to put a bunch of up elevator trim in it when flying, you should have been able to push the nose down, when deadsticking, and keep it down with elevator.

Is that the story, perhaps? You trimmed it to fly straight & level and had to put in a lot of up-elevator trim? Then when it deadsticked and slowed down, you didn't push elevator down & hold it there, to keep the nose down?

Not being critical, just trying to reconcile the obvious nose-heavy condition with your description of the flight characteristics. Something made it glide nose-up, and it wasn't that it was tail heavy.

Good luck,
Dave Olson

Yea, something is funny here, because being that nose heavy it shouldnt have been flying nose up so badly especially when stalled.

Im just trying to help, so dont think Im accusing or anything, but are you sure you have the elevator set up straight and level via the linkage when the transmitter is turned on and the elevator trim is set at center?

Also, and this sounds stupid, but is the elevator set up to move the proper way? To go up you pull the transmitter stick back and the elevator surface should be trailing edge up, and to go down the transmitter stick is forward and the elevator surface should be trailing edge down....

Its just that something is amiss here, and Im starting to think its not balance.

See if you can feel that spar there. Make sure your fingers are on it.

Oh, don't worry about me taking stuff personally, I'm an ignorant rookie trying to understand how the airplane works, so I appreciate all of your patients while I muddle though this.

First, I didn't really spend much time in the air trying to trim it out. It flew so badly that it was everything I could do to get it back on the ground. It was only up for 2-3 minutes as I made several passes trying to get it down low enough to land.

After all of the input I am pretty sure my problem is that the control surfaces where not perfectly level. After taking a straight edge to everything there are a lot of issues some that couldn't be fixed easily in trim such as both ailerons slightly tip up.

The elevator is slightly tip up as well, but that could have been trimmed out but as much as it is out it would take a bit of my throw out.

I also moved the battery and radio up against the servo tray and it's a bit better on the CG machine. The nose is only 2" lower than the tail now.

I think I'll go though my control surfaces again and then try again.

To answer some questions:

1. Yes the elevator moves the correct direction.
2. The engine was always running so I never deadsticked it, but yes I had to use lots of up elevator to point it at the ground even with the engine at idle.

Basically it has to be the control surfaces since the balance is not the issue.

Thanks again for everyones help.

schu

I've had the same thoughts too, about there is other things wrong. But after looking at the picture you can't argue that the plane is way out of balance. I think that this needs to be addressed first. I'm not saying it's not as important, but fix one thing at a time. Once the balance good then we can figure out what to do on the other issues.

RCKen,

Sounds like a good plan, I'll work on the CG issue first, then the control surfaces.

Here is a picture of how it looks with the added weight and the radio equipment moved as far back as possible:



The plane is pointed down, but only slightly. Should I run with that or reduce the weight a little?

Thanks,

schu

Assuming my floor is somewhat level, I measured from the floor to the tip of the spinner and from the floor to the tip of the elevator. The nose is 2" closer to the ground. It is pointing slightly down, but its hard to see in that picture.

akschu,
that's how it should look when balanced. If you are on the CG mark then that is where I would try to fly it. From what I can see in the picture your control surfaces are where they should be.

Yea they look pretty close when you eyeball them, but when you hold up a ruler it show a different story:

Cool, you look balanced now.

I dont think that little amount would cause much more than a roll problem. Not a nose up condition.

Check out the elevator surface with the controller and plane turned on but with the trim tab and stick at the middle (neutral in the case of the elevator) position and post a pic.

When you adjust everything (control surfaces) make sure you adjust using the actual linkage to get them as close to neutral as possible. Radio trim is the fine tuning.

Also, and VERY important. Take the servo arms off the servos, turn the radio and reciever on, then put the servo arms back on as close to the "center" point of the servo travel as possble. When the servo and radio are turned on, the servo typically will automatially go to its middle position (unless theres binding or something). Its here that you install the control arm perpendicular to the linkage so you have equal movement in both the forward and backwards directions of the servos travel. This will be the starting position of all your servos to adjust the linkage and surfaces. If you dont do this, you can introduce a number of problems.

We'll have this solved right quick.

AAAA! One more thing....Before you do ANYTHING, move all your trim tabs to their middle positions on the radio. We need to start from absolute neutral on everything. After this do the above.

Right, this stuff I did do:

Turn on TX and RX.
Move trim to center.
Make sure servo horns all as close as possible to the middle of the travel.
Use linkage to center contol surfaces using a straight edge.

Both the aileron and the elevators where pointing up, and combinded with the balance issue it made the plane fly incorrectly. Now that I have everything straightend out I'll go fly again and see if it's close enough to trim on the TX.

I am concerned about adding 4oz to the tail. Is that a lot of weight to make something balance?

schu

jwalsh1,

That aileron doesn't look like its off to much, but then again the recommended surface throw for the aileron is only 1/2" and the one in that picture is 1/4" up.

considering the motor you have on the front of it, 4 oz. isn't too much. And that motor can easily pull that weight. You're fine there.

Here is a technique that I use when setting control surfaces. Disconnect your pushrods first. Then get 2 pieces of thin wood. I use some 1/16" lite ply cut into some strips. Make sure the pieces are at least 6" or so long. What you are going to do is "sandwich" your control surface between the pieces of wood. I'll use the elevator as and example. You want one piece of wood on top of the horizontal stab AND the elevator, and you want the other piece of wood on the bottom also covering both parts. Then take clothes pins (small clamps work too) and place clamps on the wood, use as many as you can. Make sure you have both the horizontal and elevator clamped. What you looking for is immobilizing the elevator in it's center position. Now turn on your radio, center your trim tabs, and remove the servo arm for the elevator. Replace the servo arm on the servo with the control arm AS CLOSE TO 90° (from the servo) as you can get it and replace the mounting screw. Now adjust the clevis for the elevator so that you can connect it to the control arm on elevator. DO NOT MOVE THE ELEVATOR at all, turn your clevis until can be inserted into the control arm. Once you have the linkage connected you can remove the clamps and the wood.

If you use this technique you should be within a couple of clicks or so when you go to fly.

Give it a try.

Thats a good technique, Im going to use that one too if you dont mind!

Ok, got out for the second flight tonight. The plane took off fine but the trim was obviously off. I got a little altitude and worked on the trim for a minute and got it flying nice and straight. Then I had a little fun and did some loops, rolls, and even an inverted pass the length of the field. Life is good!!

When going to land I didn't cut the throttle enough and was coming in pretty fast, I touched, then bounced, then I decided to hit the throttle and climb out for another pass. Just then the engine flooded and died so I got to go rest of the way dead stick. It touched but didn't stop before hitting a chain link fence. The impact wasn't bad, the only damage was the rudder came loose. I'll glue it back tonight and maybe try again tomorrow.

Leasons learned this time:

Where to set the trim.
Run it a click or two leaner and make sure the engine transitions off of idle and back before take off.
throttle all the way back when decending to scrub the speed.

Thanks again for all the help provided, I think I'm over the hump now, flying is a bit more fun when the plane flys straight though the air!

schu

akschu,
Great!!!! I'm glad that we got the mechanical issues worked out for you. I'm glad that you are enjoying flying now.

akschu-

Glad your off the ground. Happy days with your new airship. Just keep your inverted passes at least a rudder high!

But I'm still very confused............ I'm still trying to figure how you had to give it "up" elevator to make it go down. You said this twice in your previous posts. I've heard some bizarre stuff happens in AK but I didn't think the poles were reversed down there!

I think you mean up there. AK = Alaska. Right??

Yea, Alaska, it's a great place to be.

In the earlier flights my control surfaces where pretty far out of whack, now that things are setup properly, I can land without massive up elevator.

I live pretty far north of Anchorage, and enjoy my isolation from people, which is one of the many reasons why I really didn't bother with any clubs. No offense to anyone here, and I truly appreciate the help, however, the closer I get to a big city, the more frustrated and annoyed I become with the irresponsible, superficial, materialistic, rude, inconsiderate, shallow people around me.

As far as AK goes, I have a ton of pictures. Here is a good one I took while out snowmobiling:



Go to [link=http://www.schu.net]www.schu.net[/link] if you want to see more.

Sweet! Glad to hear thats all worked out.

You photos look beautiful. I bet the skies are awesome up there at night.