A-10 Thunderbolt II 1700 mm - with plans when finished - Page 7 - RC Groups
Thread Tools
Jun 11, 2017, 07:33 AM
Scale RC Plane Lover
julescrafter's Avatar
video without music

RC A-10 #2 flight with packing tape cover (2 min 58 sec)
Sign up now
to remove ads between posts
Jun 11, 2017, 03:39 PM
Retired CAD guy
birdofplay's Avatar
Check your esc for max cells ( volts )
AND if possible Toss in a Pak with ONE MORE CELL !

Otherwise a nice stable flier.

It just needs more T E E T H !!! ;>}
Jun 21, 2017, 10:11 AM
Warbirds Lover
Dreamcatcher's Avatar
Great to see her in the air !
Jun 21, 2017, 10:08 PM
When cows fly!
Looks good! Just needs more power
Aug 13, 2017, 02:36 PM
Registered User

elevator angle of attack


Quote:
Originally Posted by eflightray
Take your pick ( a google on A-10 plans) ---

https://www.google.co.uk/search?q=A-...+warthog+plans
From these plans and looking around, do I have it right that the elevator should not be level to the horizon, but about -7 degrees?

Meaning the leading edge of the elevator should be 7 degrees lower than the trailing edge?

That seems pretty steep.

Also, I'm setting my EDF motors to +4 degrees. Meaning the the intake is 4 degrees higher than the exhaust relative to the horizon.

Thanks for any thoughts you can provide.
Sep 10, 2017, 09:42 PM
Registered User

Characteristics of A10 plane


What should be the expectation of the A10 with regard to how sensitive the elevator should be?

I've verified that the CG is in the right spot, however, when flying the plane, it seems that the elevator is very sensitive.

With other planes I've built, ensuring the CG is in the correct spot usually fixes problems such as this, but since this is the first twin ducted fan I've built, that there are likely other forces at work here.

What sort of things should I verify?

Some thoughts I have currently are:

- the angle of attack for the stabalizer is incorrect
- The elavator is too large.
- The elevator has too much throw.

While reducing the throw of the elevator will reduce the sensitivity of the elevator, it is unclear if this the best choice in fixing this problem.

Other thoughts?
Sep 11, 2017, 11:22 AM
Gravity is my enemy
Balloon Bandit's Avatar
I could be way wrong here, but I thought that if the thrust is above the centerline it should be pointed downward instead of 4 deg up. (Others more experienced than I, fell free to fix my thinking.)
Sep 12, 2017, 12:47 AM
Registered User
Quote:
Originally Posted by Balloon Bandit
I could be way wrong here, but I thought that if the thrust is above the centerline it should be pointed downward instead of 4 deg up. (Others more experienced than I, fell free to fix my thinking.)
Just to be sure I'm not painting the wrong picture....

I can fly it straight and level with no issue. If I give it more throttle, it stays straight and level, however, when going faster, the elevator causes the up and down movements to be even more sensitive.

It would probably be helpful to know that I didn't put in any expo or any other kind of mixing, so some of this would be smoothed out by some of that, however, before doing that, I wanted to make sure that the plane was configured "correctly".

Thanks for the ideas.
Sep 12, 2017, 01:48 AM
Warbirds Lover
Dreamcatcher's Avatar
Quote:
Originally Posted by Balloon Bandit
I could be way wrong here, but I thought that if the thrust is above the centerline it should be pointed downward instead of 4 deg up. (Others more experienced than I, fell free to fix my thinking.)
Hi,
it depends if the engine / prop are in front or behind the wing.
If the engine is set behind the wing (i.e. set as a pusher prop), the most high above the centerline will be the engine and the more the prop will have to be set "higher than the engine" (the angle of thrust have to pass from the engine and an area near the CoG of the plane - idealy it should be pass through the CoG spot.

This is a picture that explain why (found on the FliteTest web site) :


You can guess that if the engine's prop don't point enought toward the sky on the drawing here up, the plane will dive toward the ground when you will increase the thrust - and the plane will climb if the prop point too much toward the sky.

Have a nice day
Sep 12, 2017, 02:04 AM
Warbirds Lover
Dreamcatcher's Avatar
Quote:
Originally Posted by barjunk
Just to be sure I'm not painting the wrong picture....

I can fly it straight and level with no issue. If I give it more throttle, it stays straight and level, however, when going faster, the elevator causes the up and down movements to be even more sensitive.

It would probably be helpful to know that I didn't put in any expo or any other kind of mixing, so some of this would be smoothed out by some of that, however, before doing that, I wanted to make sure that the plane was configured "correctly".

Thanks for the ideas.
Reading that, it seems that you have near the same "problem" as we have on F3p 3D foamies that are fitted with very big control surfaces and control throws set at least to +/- 45
We solve the problem by adding a good amount of exponential on the elevator stick.

But It could be also an aerodynamic reaction that makes that the elevator could be working in a turbulent air flow at low speed and so loose of its efficiency at low speed and when you fly faster, the turbulent air flow area move backward and may be over the elevator that bring it back all its efficiency ...

Adding some turbulators in front of the elevator could help but i'm not good enough to help to calculate where and how thick they should be

or may be reducing the area of the control surfaces of the elevator could solve your problem too.

Moving (a bit) forward the CoG can also help to add stability on the pitch axis, specialy on the long nose jets because when you push or pull on the elevator stick, the long nose will act as a "mini wing" because of its big surface moving in the airflow and so it will increase the pitch force applyed on the plane.
That's why most of the fighter jets like F-18, F-5, and so many other "long noses" have their CoG located near 18% of the Main Aerodynamic Chord (Mac) - by comparing, a classic shaped aircraft and glider have generaly her CoG located between 20 et 33% of Mac

I hope this can help...

Cheers
Last edited by Dreamcatcher; Sep 12, 2017 at 02:15 AM.
Sep 12, 2017, 01:45 PM
treefinder
springer's Avatar
I tend to agree with Dreamcatcher, I would add expo before doing anything else. I interpret your comments as saying that the elevator control is too sensitive when accelerating. (is it sensitive in both up and down?). Expo can desensitize the control around neutral, while still allowing full throw when you may need it. If the total throw is just too much, than adding a half (or so) rate on a switch can help. I typically use two rates high is full throw to what I set the plane up, and low is around half that throw. I also usually add 30% expo to settle the center of throws. I often find that i want low rates for take off and landing but like high while up high.
Sep 13, 2017, 01:04 PM
Registered User
Quote:
Originally Posted by springer
I tend to agree with Dreamcatcher, I would add expo before doing anything else. I interpret your comments as saying that the elevator control is too sensitive when accelerating. (is it sensitive in both up and down?). Expo can desensitize the control around neutral, while still allowing full throw when you may need it. If the total throw is just too much, than adding a half (or so) rate on a switch can help. I typically use two rates high is full throw to what I set the plane up, and low is around half that throw. I also usually add 30% expo to settle the center of throws. I often find that i want low rates for take off and landing but like high while up high.
Thanks for the feedback.

So I'll adjust the throws so they aren't nearly as extreme and add expo. I'm sure it will calm things down.

I'm not familiar with the planes "normal" flight characteristics, so it is hard for me to know if it is behaving "normally".

It has plenty of power with the twin 70's

It seems the angle of attack for the horizontal stabilizer is working just fine.

I'm not sure how it would behave if it wasn't right, though.
Sep 13, 2017, 03:21 PM
Registered User

Franken A10


It isn't pretty, but it does fly.

It has the wings and EDF's from a previous model.

The rest of the model is in airplane heaven.

I decided to "resurrect" it...this is its new form.


Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
Discussion fms 1700 mm beaver floatman Waterplanes 2 Dec 01, 2016 06:23 AM
Discussion Is their room for 2 3s batteries in FMS 1700 mm Corsair dhenry132 Electric Plane Talk 3 Mar 02, 2016 03:24 PM
Discussion 1700 mm size planes planes weedsnager Electric Plane Talk 3 Feb 21, 2016 11:44 AM
Discussion 120 mm EDF A-10 Warthog eatond Castle Creations 0 Apr 01, 2008 01:34 PM