Is the self righting characteristic of a high wing trainer the result of dihedral in the wing or the CG being below the wing or equal combination of the two?Or in other words could one take a plane such as a four * and add some more dihedral making it more flyable hands off,a trainer that doesnt look like a trainer maybe?

ducttape,

The self righting characteristic is a result of both the dihedral and the cg location, but the dihedral is the stronger effect in most cases. You certainly can make a low wing plane more stable ( self righting ) by adding dihedral. Having said that, my observation to you is that 'trainers' don't look much clunkier that typical non-scale low wing planes, and if you buy one and fly it, you won't find it to be embarassingly ugly. When you are learning to fly, self righting is not the only characteristic that is useful. When you are landing, it is nice if the wingtips are higher from the ground, so that they aren't as likely to scrape when you have a little rocking. Get the trainer, get trained, then buy something 'hotter' looking. Just my two cents.

Good luck,

banktoturn

go with a trainer.

You will not care what the plane looks like once you fly for the first time. You will love the fact that you have a slow flying, easy to land - trainer while learning to fly.

Thanks for the replies guys,but in not in the market for a trainer. What I was referring to is a flying camera platform with plenty of built in stability......I guess I should have said "trainer like" as opposed to trainer............................

Just a thought, but if you're looking for a good flying camera platform I'd suggest going with a powered glider. Most polyhedral gliders are so stable in roll they don't even need airelons, plus they're very stable in cross winds. I've flown my 2 meter in 15+ winds with my hands off the transmitter before. Plus you'll get better range and duration then any powered airplane.

I've not flown a trainer yet that will self right despite the adverts, maybe if your a little off perfect it will come good, IF you've got it trimmed right at right power, but your not in trouble in those cases. but i've seen trainers go in because the student got it all wrong and let go to wait for the trainer to recover, what you can say is they all want to roll in and hit just past vertical.
a Lazy bee gets closest to self recovery

We've done some serious battle testing with rudder only (no airleron) high dihedral combat planes with shoulder mounted wings. There have also been several experiments (VERY Successful!) with high dihedral low winged scale combat planes controlled with rudder only (no ailerons). We have found that the more dihedral, the more they become self righting, but there is a trade off. I can't explain it in big educated terms, but...

Take a 48" wing.

3" dihedral...little self righting but very stable. Rudder control rather slow.

5" dihedral...self righting getting better...stability ok, but getting much quicker on rudder control

7" dihedral...really good self righting, VERY quick roll axis control with the rudder, this is a sweet spot for rudder only combat planes. You also begin to get a noticable in flight tail wobble as the vertical and wing work to keep the plane upright (as if they start fighting eachother for control of the plane)

10" dihedral...when you let go of the sticks it can't right itself fast enough! Even from inverted it flips over like a weeble. Self righting is amazing...but the trade off is stability. The rudder becomes EXTREAMLY sensitive (snap roll city!) and the inflight tail wobble becomes severe. This is also about the point that you start loosing lift and pitch control starts becoming less effective.

Hey Tattoo...

Very nice study...with some interesting results!

Bill

Hmmm.interesting info.....what brought all this to mind was a neighborhood electronics genius/idiot savant knew in the past I had flown alittle r/c and asked about the possiblity of GPS guided drone.I think I best just give him the number to NASA... on second thought,they might arrest me also.but thanks for all the replies.I found it interesting reading.Thanks again

Tatoo -

It is fairly easy. There is a aerodynamic term - Clbeta - defined as rolling moment due to airplane sideslip or mathematically is rolling moment / sideslip angle. Clbeta is the provider of the responses you have listed.

Clbeta basically gets bigger as dihedral gets bigger. Clbeta is higher on a cabin airplane than on a low wing airplane.

beta, the sideslip angle, gets big when the fuselage yaws and this is caused by
1. sideslip caused by rudder application or
2. sideslip that happens when the wing is upset from a stabilized condition.

So apply rudder and the high dihedral wing causes a high rolling moment.
Somehow end up upsidedown and the high dihedral rolls the airplane upright.
A little gust comes along and the high dihedral seems to take care of it right away.

It is what allowed the rudder only contest class of 40 years ago to work and what allows a rudder elevator ship to function well.

But it is neat when what you see in practice can be seen in the theory also.

Tatoo. The wobbling may be the onset of Dutch Roll. For extreme dihedral angle like that it's often good to increase the size of the vertical fin+rudder area. If it was all stable at the 5 inch mark try bumping up the vertical tail area by 10% to 15%. That should restore the groovyness with no bad side effects on the rudder response.

Old free flight trick. We are used to dealing with lots of dihedral..

For your purpose, a camera carrier, the FMA Co-pilot will do what you want.
It will keep the wings level, and a constant fuselage angle at a particular power setting.
You do the "heading hold" mode the wing-leveler provides for aerial photos.
Here's a photo I took this morning with a side-looking camera. Note the "same road"..
The plane deviated sufficiently in heading between two photos that the perspective changed enough to make the images not fully "stitchable".
For a vertical image this isn't all that important, but when looking obliquely perspective does matter..