Help! Nemesis CG issues.

[Dreskyn]

I am having a lot of "growing pains" with the STEM FT EZ3 Space Flyers
in particular the Nemesis.
The instructional video is from 2020, and the STEM pack has been updated since then. So a lot of things are different (not necessarily bad), just different. There are no replacement props for one. This was a bit of a disappointment as we knew that we were going to crash these over and over. knowing there were replacement props in the kit, we didn't purchase any extras.

But the biggest issue we had was that we followed the directions, and when it came to the motor mounting and proper way to attach the props..... it didn't match up. So through a lot of trial and error, we finally came up with this orientation that worked. With the nose of the plane pointing at your chest, and the plane is upside down. The red motor goes on the left hand side and the blue motor goes on the right hand side. The "B" prop goes on the RED motor and the "A" prop goes on the BLUE motor. The rounded side of the prop (the part that also has the "A" or "B" stamp) faces away from the plane.

In building this model, without the electronics installed. it flies nice and strait as a chuck glider. We marked where we felt the CG was on the plane. Then when mounting the electronics, we were very careful to make sure we kept the CG the same. We then threw the plane as a chuck glider again and it flew with a little more high alpha then before, but still flew nice and strait.

The second power was added, it immediately went into a nosedive and smashed the plane to bits. We are struggling to get this plane to fly properly. At this point we have the battery poking straight up threw the wing right next to the receiver. It "flies" at a very high alpha, and if you give it full throttle, it will loop. the loop is "fun", but the flying is VERY wobbly. lowering the battery, or moving it slightly forward results in the plane doing a full nosedive.

Any advice would be appreciated. We were all excited on building these, but after all the issues with the Nemesis , they didn't want to build the others.

Oh, and as a tip from me on this kit. we did (thankfully) make tracings of each of the parts before we built the kit. So on posterboard we have the tracings. But what I found to be much better.... since you need to peel the paper off the foamboard... peel it very carefully and slowly. get it to come off all in one piece. Now use packing tape to tape that "skin" on another piece of foamboard. You now have a perfect piece to cut out, and it is reusable. each time you use it, the tape gets thicker and the "skin" becomes more resilient. Start cutting out the smallest / weakest holes first and finish with the outside edges last. I saved the "skins" from both sides.

 

[Dreskyn]

I could really use some help here. Either there is a massive redesign needed or somewhere the basic instructions are wrong. It will fly great with the electronics installed as a chuck glider.... but put ANY power to it and it will nosedive. Otherwise we have to make it be a a huge high alpha so when the power is applied it levels out at about 3/4 throttle, but any more power and it does a loop.
We bought this kit because they wanted to fly the Nemesis.

 

[Piotrsko]

Might want to start with motor offset. Adding power nosedive says you may have too much motor down thrust, and you have two. Or not enough up trim. If it does an extended glide using part power <30% I would unscrew the motor mount lower screws at least one full turn and put something under each bottom mount about the thickness of that gap and re-tighten those screws, then add a small but noticeable amount of up elevator  TRIM, what us old timers called " couple clicks of up". This will affect the motor off glide, some. It may bobble and semi stall, back off trim a click down. Technically, you may have to fiddle with trim until you get good at flying or the plane starts behaving

 

[Merv]

I could really use some help here....

Some video would help us diagnose the problem.

 

[L Edge]

1) Do a review of the build video. and buy a 8x 10 blue tarp($7.99) to say hang in cellar and put a hook in bottom of the tarp

Concept of EZ to prevent and how to avoid crashes.
What you want is the following:

To set throttle at 1/2 and when you release thrown airplane, it should try to maintain flying level. Stand 5 ft from a 8 x 10 ft hung tarp(cellar for example) that is slightly hooked on the bottom so plane hits it and slides down and stops in the hook. Hey, now no damage.

To adjust it, if it drops nose down, move battery back a small amount and rethrow until you get it right. Now move back to 10 ft, Put throttle at 1/2(same position) and chuck level. Say it starts to climb. So now you need to move battery forward slightly and retry. Point to get it so only adding a tweek/backing off a small amount makes it fly level.

Now go back to 15 ft. This time 1/2 throttle, chuck plane and play with throttle(more or less) and make it fly level.
Back up more in cellar and redo.

Concept is
approximately 1/2 throttle will have it fly level
add more than 1/2 throttle, plane will climb and yes certain planes will loop
subtract 1/2 throttle slowly and it will glide slope, pull back throttle alot, it will drop quickly(especially if it is in the wind).
turn corners, at 1/2throttle say, it will drop, so add a blip in turns.

So outside, launch at full throttle, climb, level off at half throttle and fly around play and to land, a little less and it will slope it way in to you. Turns will constantly blip and then add or subtract small amounts of throttle. Wind makes adjustments necessary and quick to make it fly under control.

Here is my B2 Spirit that has no rudders, run by the EZ system, it weighs 39.3 grams

Here is my flock of five using tarp in cellar to test my designs.

Just got out of hospital, sorry i didn't respond before.

A sideview would give you the "J" so plane stops. By sure throttle is off when it hits the tarp. When you can direct plane and feel comfortable, try left or right for turns. Start close so you can determine which switch to use.

 

[Dreskyn]

I recut a new plane.
found it's CG.
and we did another try at flying it.
and it did the same thing.
we built another one, didn't remove the paper this time. (hoping for some added strength)
for whatever reason, it flew awful, but it flew.....
Instead of trying to move electronics back and forth, we added static elevators....
It flies much better. We had to glue the canard on due to some warpage (no pun intended) instead of trying to recut the slots...

this is made from Walgreen's foamboard ($5 per sheet) it is much denser (thinner) than rediboard.... but it was what we had on hand.

 

[L Edge]

I recut a new plane.
found it's CG.
and we did another try at flying it.
and it did the same thing.
we built another one, didn't remove the paper this time. (hoping for some added strength)
for whatever reason, it flew awful, but it flew.....
Instead of trying to move electronics back and forth, we added static elevators....
It flies much better. We had to glue the canard on due to some warpage (no pun intended) instead of trying to recut the slots...

this is made from Walgreen's foamboard ($5 per sheet) it is much denser (thinner) than rediboard.... but it was what we had on hand.

View attachment 246410
View attachment 246409

2 quick questions:

1) Did you put the dihedral in for the wings? If not, build again.
2) What is the weight in grams? Above 50 grams, it gets bad and over 60, very poor flight.
3) Right CG initially from model?

Have no experience with your model, I just make my own. Still need to do my steps 1/2 throttle and then move battery to get it to fly level.

Do video where I want you to hold it vertically with throttle running and see if you can release quick and grab and have it sorta of hover. Then hold it by nose, add throttle and try left and right differential so it tic tocs.

Then make video of getting it to fly as best as you can. Don't understand why it won't do as I said it would.