In all this theory everyone forgot to ask one question.

Are you flying north or south of the equator?

If you are north of the equator I believe that down thrust will not cause the airplane to climb when power is added.

On the other hand or other side of the equator (south of it) it may very well cause it to climb.

Think about that one!

microflight ,

I think you are on to something.

Weldo

Hmmm.
When I had my trainer I took out the plain bearing .40 and put in a ball bearing .46. I also took all the downthrust out and it looped on takeoff. Hmmm.
But, I was pointed NNE. Maybe if I was pointed SSW it would have just nosed over...

Maybe it was that Solarflare!

Jeff

Well, just when I thought I had this thing figured out......Someone has to bring up the equator.......
Ya know guys.....I have read all the posts and come to one conclusion.......

We have gone from the moon to the equator...All this poor guy wants to know is why it climbs at 1/2 above throttle......What would you guys think if you read this thread and ask that simple question????????
The gentleman that ask the question has a CG problem....
I will not go into all the reasons why.......
HE has a CG problem!
Most of us do.
5x5

The problem with all of this is that model airplanes have not studied aerodynamics. They just don't read all of your theories.
But Ron Moulton, a famous modeller, once wrote "downthrust is the modeller's friend".
This is really basic stuff:
If your airplane climbs when you add power, put in downthrust until it stops doing that. If the amount of downthrust you have to add ends up being really silly, change the stab(or wing) incidence. But chances are you won't have to do that.
Downthrust is what you need.

Ok .......With all that swallowed......Don't you agree the CG should be checked first?????
Read the instructions on your toaster.............
IF TOASTER FAILES TO PRODUCE TOAST.......CHECK THE FOLLOWING:
1. IS YOUR TOASTER PLUGGED IN?
nuff said,
5x5

Fivesquare,just a little edit there,nothing to worry about.Here it is in basic of basics.More power,more speed,more airflow over wing make airplane climb,less power,less airflow make airplane descend.Eventually,most trainers having postive dynamic stability will try to regain there original flight path,I.E. climbing and descending,climbing and descending for quite awhile until they are almost back to the original flight path.This is where elevator use comes in,if you go to full power without down trim,the plane will climb away simply.Most acro type airplanes have are nuetrally stable,thats why they keep going in what ever direction you leave them until a control input is given,also with the symetrical airfoil they dont care which way is up or down.

King.....With all that you said...do you have a little "twitch" that could say ...................YOUR CG IS OFF!
I am not designing the space shuttle.......I am stating the facts one should check before one starts the butcher knife to the wing or, starts adding washers and" thingingies" to offset the engine.
This guy asked one simple question.......We have him so confused now.....He may try to fly mamma's hairdrier!
All I am saying is ::::::::::::::::::::
TROUBLE SHOOTING GUIDE.
Check CG First!
sorry ...I am rambling.......
5x5

Now dont forget to check flux capacitor ,make sure it's linked to di-fromide discharge unit and that it is not bypassing the initial compressor section.If that doesnt work,then I dont know what will

More down thrust....no I mean less.....no I mean bigger prop...no smaller prop.....no I mean positive wing incidence or is it negative.....change the throttle servo.......or is it elevator
O HELL just sell the damn thing......

Just kidding!!!

Come on guys, this isn't going to get weird now... is it?

Weldo

Weldo, this got weird after the 4th or 5th reply. JK! I just wish I could have gotten in on all of this earlier.

Now, I hate to tell you this, but all of these guys are wrong. Let me ask you this, are you left handed or right handed? Couple this with the equator theory and add......oh forget it, just fly the dang thing!

Just don't get into the tub with that hairdryer. I know, I know, Someone will argue the point.

No matter what he does, change CG, up or down thrust, It's still not going to change the character of the airfoil. It's going to climb at hi throttle, & drop at low throttle. Why is veryone trying to destroy this poor guys airplane. IT'S NORMAL!!!!!!!!

Just trim the plane at full throttle and enjoy yourself. If you don't like the way it flies then give it to a friend and let him worry about it. Life is to short, and this is getting redicurus. I like that word... redicurus. Sounds kind of ancient....

Weldo

I am going to go with trim at full thottle and forget it......

Even though this is fun to read.........

I even went out and flew this afternoon just to study the situation, It may take further research.

Bang it on top 2 times and on the side 3 times, then pick it up on one end and drop it.
If that don't fix it, it's broke!

And always remember, when at full throttle you're tongue must be on the left side of your mouth!!!

And to think, all this time I thought it was the right side of the mouth. Man, I learn something new every time I visit this place.

Weldo

The Crow, sorry about our goofing off. We like to have fun.
No harm intended.
If the CG is correct and the stab and wing are in their proper orientation, trim the model at your favorite flying speed. That way when you decrease throttle it will slowly descend. Add power and it will climb.
Trainers have a natural tendancy to climb. That is the way they are. You may want to consider moving up to a mid-wing or low-wing aerobatic trainer for a little more stable performance.
Years ago, my instructor, gave me a very important bit of advice: the KISS method. Keep It Simple Stupid! It works. The more you alter the way the canooter valve operates in relation to the kadutzit pin the more variables you throw into the equation and the greater the likelyhood of something going wrong. The frammish pin is a whole nother story.

Best of Luck,
Jeff

Nuff said,

I think it may be time to put this baby to rest......

Weldo

Crow, listen to Taildragger! ir Knocker pilots rule. (What we rule is not clear, but once we find out -look out.) (Aeronca) Champ, Mark.
Check out a book called Stick and Rudder by a German fellow named Otto #### Having a senior moment here but that should get you in the ball park.

Weldo, you just need to be flying inverted more, thats all

Fellas, thanks for all that advice.
As part of my check list, the CG's at exactly as the manual says. The only reason I notice this situation is I also have another trainer (RCM trainer 40) and it did not have that "problem". As far as this is inherent in a flat bottom wing, these two planes are both flat bottom winged.
I will try down thrust 1st and then up thrust.
After that, i'll start flying with my tongue in the left cheek to climb amd right cheek to descend. If that won;t fix the problem, i'll give it to my 11 year old son who flies better than I am
Again thanks for the input

The crow,

I just went thru this exercise on my bipe. With every throttle change the plane would climb. Everyone had a suggestion, but the thing I noticed was in level flight chopping the throttle created a MAJOR nose up attitude. It was a bear to fly and we almost crashed it on landing, everytime you backed off the throttle to flair, it would nose up!

Go by the trimming chart. Try chopping the throttle and seeing what the plane does.

I added 2 deg of upthrust and 2 more degress of right thrust and it was like having a new plane. The amount of down/upthrust and even right thrust will vary on each plane based on engine size, and also the prop. Changing props can change your thrust angles, however one or two sizes is hardly noticeable and not worth fooling with.