Extra 300 rolling while doing a loop
 

Hi there I have an extra 300 1700mm kit with .76 engine. I am new to flying it. I am getting on good doing loops rolls inverted ect. The plane is ballanced. This is my first plane after my trainer. When I do a loop pulling right back the plane rolls to the right halfway through it when its inverted. It really is pissing me off. I dont know if its meant to do it or somethings not right. The throws are equal and its ballanced left right forward aft. I can do a loop not pulling right back and it wont do it. It only does this full throw, and doesnt matter if ive got power on or not or fast or slow. Any suggestions as to why it does this, is it meant to? my trainer coulod loop all day and never roll in the middle.

RE: Extra 300 rolling while doing a loop
 

If the extra has split elevator servo's, check to see that both elevators travel at the same speed and travel the same distance. If there is any difference in their travel , depending on how much, they can act like ailerons. If the elevator is single servo with a connecting rod between them, check for twisted or warped surfaces. If neither is the case then you need to probably reduce the throw on the elevator. Some planes tend to roll with too much elevator applied. Hope this helps.

RE: Extra 300 rolling while doing a loop
 

G'day Mate,
It is known as a snap roll, it happens because, you have stalled the tailplane by using too much elevator throw, cut back on the throw, so that full up elevator does not cause a snap, using duel rates or total throw, & it will stop happening. A proper snap roll is a great manouver, but a snap roll when you don't want it can cause BAD things to happen.

RE: Extra 300 rolling while doing a loop
 

Mark

The rolling you are seeing is caused by an incipient tip-stall. It is a "feature" of this type of aircraft. Thats why it is so nimble. Too tight a loop and not enough airspeed makes things worse. You mentioned that it is kit-built. Often the leading edges of the two wing-halves are not identical which could also cause this. A sharp leading edge makes the plane snap better while a blunt one softens it. Wild Hare, for instance, have 2 different wings for their 34% Extra 330LX. The original, thicker & blunter wing, did precision flying well, but fared poorly in advanced IMAC. The newer, thinner & sharper wing, solved this.

Enjoy your Extra, fly within it's limits.

Safe Flying!

RE: Extra 300 rolling while doing a loop
 

i agree, i have an older hobbico 300S AWARF w/ o.s. .91 surpass. great flyer but it's days were VERY limited when i first got it. every time i moved the right stick back more than 1/4 of the stick's movement it would go into a violent snap roll. i found out i just had too much elevator. the MAX throw on mine was only 5/16 inch (or app. 8mm) up and down. since i've corrected this, this is one of my favorite planes. however keep in mind that when flying in moderately high winds it will still snap when i do a loop flying into the wind (i guess the added wind adds to the surface throw. correct this problem and you'll have a "keeper" on your hands. keep us posted as to how it goes.

RE: Extra 300 rolling while doing a loop
 

All the above is true, but you need to also realize that a CG that is too far forward will do that as well.
Make sure your CG and CL are close.

RE: Extra 300 rolling while doing a loop
 

Yep, the aircraft is snapping and can cause catastophic results if it occurs a low altitude. Cut down on your elevator throws until it will perorm a loop without snapping out. Adding exponential on your throws will help also.
Because the snap is essentially a tip stall it generally causes the most trouble if you have to add sudden power when at low altitude such as on landing. The airplane will tend to snap out and roll over onto its back ending in a crash.

Regards,
doubledee

RE: Extra 300 rolling while doing a loop
 

Hi!
You probably just have too much elevator throw!
Also check your Cof G it might be to far forward or rearward. If your airplane is very thuchy on the sticks it is too far to the rear (or you have excessive elevator throws). Normal throw (up ) is around 1-2cm measured at the trailing edge of the elevator.

How does your airplane react in a sharp horizontal turn (ie bank to the left)?
Does it keep on going without the nose going down or up when you bank sharply?
A well balanced airplane will always hold its altitude in a sharp pylon 90 degree turn without its nose going down or up.
An airplane with too forward Cof G will nose down in turns.

Just because you have an aerobatic airplane doesn't mean is shouldn't be docile when you want it to be...

Regards!
Jan K
Sweden

RE: Extra 300 rolling while doing a loop
 

Fantastic replys guys thanks. I have quite big throws on my elevator and I fly 60% expo I dont use dual rates. I will reduce the throw and expo thanks alot.

RE: Extra 300 rolling while doing a loop
 

Guys I reduced my throws to about 10-12mm each way it worked great
I want to know if there is any other way of stopping the snap roll because I like hovering and the isnt really enough elevator travel now to do this?

RE: Extra 300 rolling while doing a loop
 

G'day Mate.
Use your duel rates, have full throws & as much expo as you need on high rates, & use for hovering or whatever, & on low rate, lesser throws, & less amount of expo for "normal flying".
That's what they are there for, you might as well use em.
Also you should trim your plane, use this trim chart & follow the steps, it will make a good flying plane, a GREAT flying plane. http://www.palosrc.com/instructors/trim-chrt.htm

RE: Extra 300 rolling while doing a loop
 

Mark,

Take the plane up to altitude, cut the power to idle and enter a steep dive to build up speed. Next you want to pull into a loop keeping power at idle. If the plane tracks straight you many want to remove some of the right thrust. It it still tracks off, then you have to start looking at the structure, setup, etc.

Hogflyer

RE: Extra 300 rolling while doing a loop
 

Cool thanks guys I will try that