I sent my mx2 with a dle30 for the first time today. I was lucky to land her safely......I thought I had the plane balanced correctly. upon take & a little elevator she went straight up, I backed off throttle & got her straight again, but every time I gave it any throttle it wanted to go noes up & fly. Should I apply more weight on tail or try downthrust on my engine install. Thanks for any help.....I think I read somewhere to ignore the manual cg recommendations & go 5 1/4 for CG.....

How did the plane react on trying to land?

I flew around about 5 minutes total time. After I kept throttling down it finally deadsticked on me & It landed as normal, I did have control upon landing

How does the location of the CG agree with the one you get by using this website? Dan.

I,m not sure Dan, I got the info redwing put up on youtube about the mx2 build

Nose pulls up with the application of power= too much engine up thrust. Nose dropping when power reduced implies the same. Since you had control power off I would be using an incident meter to establish just what the thrust angles actually are.

Elevator trim can cause a lot of issues if overlooked. First flights can be a lot easier when a little nose heavy. Never, ever, trust an instruction manual to be correct with either CG or control throws. Each is an individual performance preference item with some manuals being close while others are not even in the ballpark. The safest flights will always be nose heavy. Not generally the best performing but safest for establishing a starting point. Establish CG fine tuning after the first couple of flights, using trim offsets as a general guide.

is there a method of checking the angle without buying a 50 dollar new tool, thanks.....

I suppose you could find some way to fit an angle gauge to the engine output shaft and use the same tool to establish what the wing and tail incidence are at. However, I have this outlook that if you intend to play you should have a generalset of the tools required to do the job correctly.

How much will the plane have cost per flight when it hits the dirt?

I have taken that point into consideration!!! This sort of measure is new to me. So this maybe a stupid question.... The angle thrust would vary when the plane is sitting on its landing gear versus sitting on a CG balancer perfectly balanced correct??

I do use a degree wheel to measure my elevator & aileron throws. I use a box or something until I get the degree wheel perfectly lined up with the aileron & elevator & move the sticks to get them where I want them. I have them both pretty low. 20 degress or so for first flight.

Dave, Forget what other information you got from somewhere else about the CG. Use that website to calculate where the CG should be for a stable flight. You will have to make some measurements and do a little drafting. First, measure the root chord, tip chord( ignore the wing tip), span (ignore the wing tip again) and leading edge sweep back ( ignore the wing tip again). Use those measurements to determine the following dimensions at that website;

A: With the leading and trailing edges projected to the center line of the fuselage you can now determine the A dimension
B: You have the B dimension from the wing tip chord.
S: Get S, the leading edge sweep, from the the drawing you just made.
Y: The half span Y is also available from the drawing.

Put in 30 in the "Enter %MAC Balance Point:".

Hit "Calculate CG:". This CG position is the correct one for your model. How does it compare to where you have it now?

I have a CAD program that I can do all this for you if you send me the dimensions of your wing and width of the fuselage.

Dan.

Dan, I'll get those measures, be right back

I assume the width of the fuse directly above wing tube??

Yes, you can use the one by the tubes. That will be accurate enough. Dan.

the width of fuse directly above wing tube is 7.5 inches....not sure how to measure the rest

The root has a weird flare where it hits the fuse.. are you familiar with the mx2 wing?? root = just under 20 inches wing tip including aileron = just under 10 inches

You can have a rough idea about the thrust angle, even if you don't have an incidence meter.

The thrust angle has to be way out of wack to induce the reaction that you describe.

I bet your plane is rather tail heavy.

No harm in adding nose weight and see how it reacts, while keeping the power low.

Dave, I got this image from their website. It looks like the leading and trailing edges are straight and there is a small fillet against the fuselage so I don't need the fillet information, just the straight stuff. All I need is the span and leading edge sweep. Dan.

But it sure didnt feel tail heavy when it deadsticked & floated in

Dan, keep in mind I,m kinda new to the terminology, I do thank you for your help. The wing span is 32 3/4 dont know what the sweep means

What is the manual CG recommendation?

With 20" at the root, 10" at the tip, and symmetrical tapering, 5-1/4" seems not to be reasonable.

20" + 10" / 2 = 15" MAC

0.25 x 15 = 3.75"

3.75 + (20 - 10)/2 = 8.75" measured at the root back from the LE.

That is just a rough calculation; let's see what the calculator says.

The wing span should not be 32-3/4" but bigger.

the manual says 4 3/4

if anyone reading this thread has the mx2 & understands what dan is asking for, could you post it for me thanks

Measured from?

Hi Dave, Here's an image of the dimensions you have given me so far. The black lines are what I have received. I need the question marked dimension of the leading edge. As soon as I get that, I will be able to use the CG website to get the correct location. Dan.