Minimoa 105"

[Andy Hoffer]

Eh Bien!  Tirez-tirez!  C'est très jolie!! 

Andy

[GuyOReilly]

I was not happy with the cowling I previously made, so I made another one using @Frank v B balsa wetting method.
The prop can now fold properly.
!st photo, unpainted.
2nd view from the top.
3rd front view to show the air circulation to cool the motor.

I must say I am happy with the results.
More sanding and more painting needed when this coat has cured.

[Andy Hoffer]

Bonjour @GuyOReilly ,

Ou est le reste du pilote qui va avec les chaussures en photo #7562?!!  Est-ce qu'il disparu en shop vac?? 

Andy

[GuyOReilly]

Now that the Spitfire is completed, back to the Minimoa.
The wings will be re-done completely.
The existing construction as shown on the plan is not satisfactory as it does not allow for ailerons.
Also, the wing brace shown is small and weak (IMHO).
Step 1 salvage whatever balsa I can from the existing construction, including spars and sheeting.
Step 2 will be to cut ribs... many, many ribs...
Step 3, well I have not thought about that yet...  I will keep you posted.

[GuyOReilly]

A bit of progress, the spoiler were added.
These were not included in the original plan.
The movement is limited due to space and the servo arm hitting the spoiler when closed.
They should provide some assistance with the spot-landing.

https://www.youtube.com/watch?v=ngG3EbD_G6o

[GuyOReilly]

Guess I should change the name from Minimoa to Sortamoa.
Made multiple changes and modifications along the way.
Should be ready for wings to be covered in a week or so, depending on amount of sanding done.

[Frank v B]

Guy,

Kinda-Moa, pseudo-Moa, Franken-Moa, Chernobyl-Moa....

Seeing the photo with the head-on view it is so expected that the wings flap.

Keep going.  Easily surpasses the 50/50 rule.

Frank

[GuyOReilly]

Got back to the Minimoa (renamed "Sortamoa") and covered the wings.
Is that plane ever large!

[Andy Hoffer]

Hey @GuyOReilly

Looking good! I like the pilot's straw summer flying hat on top of the U-Haul box.  Very trendy! 

Andy

[GuyOReilly]

Oh Oh... The aileron servos jitter.  Is that fright of the flight?!? 
I found the following article : http://www.charlesriverrc.org/articles/flying/tomhoopes_solvingservojitters.htm
Which suggests the following solution, my highlights:

"... little math and collecting of empirical data (testing different values) indicates that a small monolithic or ceramic disk capacitor of 150 pf to .001 uf (pf=picofarad, uf=microfarad) will do the trick. Solder the capacitor as close to the servo as possible and connect it from the signal lead to the ground lead. Remember to use heat-shrink tubing to avoid short circuits.  ... The capacitors are generally cheaper and easier to acquire. At your closest Radio Shack, look for P/N 272-125 (470pf) or P/N 272-126 (.001uf). ...  Remember, solder the capacitor as close as possible to the servo and place across the signal and ground lead."

Did anybody use capacitors to solve this type of problem?
Thank you.
Guy

[Andy Hoffer]

Hi @GuyOReilly

Great article.  I haven't used capacitors for this purpose but the theory makes sense to me.  You might want to check some other servos with equivalent length leads to see if the problem still occurs, to determine if lead length really is the problem.  You want to be sure the problem doesn't lie with the controller or potentiometer in the aileron servos, as opposed to radio interference. 

Andy

[GuyOReilly]

Hi @GuyOReilly
Great article.  I haven't used capacitors for this purpose but the theory makes sense to me.  You might want to check some other servos with equivalent length leads to see if the problem still occurs, to determine if lead length really is the problem.  You want to be sure the problem doesn't lie with the controller or potentiometer in the aileron servos, as opposed to radio interference. 
Andy

Thank you @Andy Hoffer for the suggestion. 
I swapped one of the servos and the problem went away.
Bad servo was causing the issue and that one will be cleaned for another use at some other time.
Now, onward with the build!

[GuyOReilly]

@Andy Hoffer nope, still bad...

[Andy Hoffer]

 

[GuyOReilly]

@Andy Hoffer I took a few minutes off work (do not tell my boss please) and tried the servos.
Both work, no jittering whatsoever!!
I will use your 2 Topfire servos.
Thank you so much for taking the time and for your generous offer.
Hopefully the "problem servos" will be diagnosed and will be suitable for use in the DR-1.