I have a composite Kangaroo and I am trying to find out where to install the 4 washers under the engine mount bracket. Four on each side I think. It is difficult to tell from the picture in the manual but it looks like they go under the bracket and on the two rear bracket mounting bolts so the front of the engine tilts downward. I want to be sure before I fly it!! Can anyone help me before tomorrow. I am hopefully going to fly it tomorrow, weather permitting...Thanks for the help.

Wowa wait a minute...the engine just needs a LiTTLE down thrust 1/16 inch. easy boy....the Roo is very light on the controls...1/8 inch up on the elevators.(reflex) and take her nice and easy...Handle the controls like she's a supper model, not a dime store hore. NICE AND EASY.

have fun .......the Roo is a great bird.......

Andy

Gary,

The directions state and show four washers on each side under the back of the mount. Though I haven't flown the composite Roo yet, this seems excessive. Most of us with the original Roos ended up with 1/6" under the back of the engine. Andy was also correct about the 1/8" reflex. I do recommend that you put different rates on the ailerons as 20 mm provides a high roll rate. Have fun today.

Thanks for the help guys but I do have another question. What are you referring to when you say the elevators should have 1/8" reflex. I have been flying for almost 20 years but this is terminology that is not familiar to me. This is my first plane with elevons and I am wondering if this is something that refers to setting up the elevons. Could someone please explain and tell me how reflex should be used/setup on the Kangaroo.

"Reflex" (in this case) refers to the upward angle of the airfoil/aileron at the wing tip.

All flying wings need reflex to offset the fact they have no elevator . Elevators provide a moment to stabilize the lift of the wing. Reflex does this for flying wings. (Tailess aircraft)

It is the consensus of the Roo pilots that 1/8" of up elevon at neutral is what the this aircraft needs to fly like the trainer it's supposed to be.

Hope this helps, not just to confuse you further,

Terry, Thank you very much for clearing that up. I guess that I should have figured that out since I am familiar with reflex which I think is built in to conventional aircraft for the same purpose of stabilization. I believe that the BVM T-33 I have has reflex built into the wing tip from the factory. I will add this to my programming and thanks again to everyone for all of the help so quickly.

What you have in your T-33 is "Washout". Washout is to help with tip stall. It makes the wingtip stall after the wingroot, by decreasing the wing AOA at the wingtip.

"Reflex" is: Looking at the wingtip from the end, the slight curve upward of the airfoil at the trailing edge of the wing.

More confused?

Thanks again Terry. See that is why I am in sales and not engineering!! Good thing I don't design aircraft for a living.

I agree with Bill, the ailerons are pretty sensitive at the recommended throw. I put them on dual rate and use less travel till you decide what you like.

OR you could dial in 25% expo, Then you don't have to look for a switch.

Expo also takes the first flight "Shakes" out of the aircraft.

I typically use both dual rates and a lot of exponential (anywhere form 40-75%) for all of my aircraft. I like the smooth feel of the controls that exponential provides. The aircraft just flys more smoothly in the air I think.

I do use about 30% expo on mine, but it got me in big trouble when I used it on the rudder.
Was taking off in a crosswind and was pushing right rudder to keep it straight, when I ran out of expo and it veered sharply to the right. All that lost travel comes back in the last bit of stick travel, better be ready when it happens. I reduced the expo on the rudder and the travel.
Also added a gyro just for insurance.

No problems since.

Terry,
you said "It is the consensus of the Roo pilots that 1/8" of up elevon at neutral is what the this aircraft needs to fly like the trainer it's supposed to be ."

Does this mean when I setup the elevons instead of having them flush with the wing they should have 1/8 of up?
Won't this make the Roo climb in flight?
I should be getting the first flight on mine this week and I am trying to learn as much as possible,

Thanks RC Universe and all of you who post information,
David

David,

Most Roos trim out flying straight with 1/8 up elevator. I also agree with the expo. I use 30% on the elevons along with the dual rates. I don't like using dual rates for general flying, just the first time up just in case things are too sensitive.

Guys,

All wings need to be at a high AOA in order to create lift. in a typical tailed aircraft, either the wing is positioned at about 1 degree positive, or the horizontal stab at about 1/2 degree negative. In a tailless aircraft, the wing cannot be positioned anywhere in relation to the rest of the aircraft, since the wing IS the aircraft, so the control surfaces do the job of putting the wing at a high AOA, thus generating lift.

I hope, I have explained it correct.

BRG
Chris