Has ayone flown a Kangaroo or Hotspot with split control surfaces ( 4 servos), where the two inboard surfaces function as elevator only, and the two outboard ones are like elevons ?

How does it fly compare to a plane with all four servos as elevons ?


The reason Im asking, is because the guys at my club ABSOLUTELY want me to use 4 channels for the elevons. Otherwise they wont let it fly. But with my Futaba 9CHP I can only use 2 seervos for elevon and slave another 2 servos to the elevator or aileron, not elevon. So the last 2 ofcourse would go to the aileron function.

SJ.

Each side works together as elevons, Use a Y harness on each wing,plug on side to the elevator channel and one side to the aileron channel and mix them with elevon mixer on your radio
David

Why don't you use y-harnesses?

The elevon mix has one side of the model on ch. 1 and the other on ch. 2.

Place the two left wing servos on a Y-harness and then plug the harness into the appropriate receiver channel (1 or 2). The same for the opposite side.

Craig

Sorry DC, we must have posted at the same time!

Craig

But this would only be 2 channels from the reciever right ?

They want to use 4 channels/plugs from the reciever for redundancy......if you loose a channel.....they say.

SJ

No problem Craig

SJ be sure to get as much elevator throw that you can, It will help with your rotation on take off, (I also hav 30% expo on the elevons). Another thing is the Roo will slow down on landing (this will help keep it from doing the Kangaroo hop), I have seen alot of guys landing them fast and bounching it. I don't know about everyone else but when I slow my Roo down real slow it will start to bobble a little, that is when I let the nose come down and let it glide on in. I am not an expert but this is whatIhave learned from flying it.
Good Luck
David

I fly Futaba also and I just use channel 1 for aileron and channel 2 for elevator and mix them with the elevon function.
David

Hi SJ

Why don't you contact Leif at SimJet. They have two factory Roos plus The Demo Pilot Kel's Roo. I believe they have one or two set up with Y cables and one set up with mixed elevons.

Ed

Thanks for the fast reply`s.

DC1163: I dont quite understand. But you use Y cables ?

SJ.

Hi SJ. That reasoning seems kinda funny to me,

If you lost 1 ch in any aircraft, chances are you will have serious problems... How well would a decent prop plane fly with no elevator or aileron control? Also, the Spot required LOTS of elevator and very little aileron input. If the elevons were driven independently and 1 were to fail, the resulting roll rate may not be controllable with the remaining 3 surfaces. If they still have a problem, maybe try a dual receiver system...

I have a Hotspot, as many others do with 1 servo per wing. I use the Hitec 5945's with 2 x 5-cell packs for redundancy. They are big time overkill when set up properly so there's not really anything to worry about in my opinion. You are more likely (although not all that much if its built well) to suffer a crash from a hinge pulling out, linkage coming loose, rudder flutter, etc...

Good luck,
Kelly

wow...more fast reply`s

rcav8tr Ill talk to Kel...... It`s actuly from him Im ordereing my roo

Thanks

Thanks Kelly

I think that using 4 channels is a bit overkill.
But Im new to this Jet stuff, and realy cant disagree with the guys that overlook my model.

I have the left wing servos in a y harness plugged into channel 1, the right wing servos in a y harness plugged into channel 2.
David

Ahhhh...I thought so...

SJN,

I have 4 separate servos on my 'Roo operating independently as elevons. I simply used two receivers with separate switches and separate batteries. I connected the two outboard ones to one receiver, and the two inboard ones to the other receiver.

The place you are most likely to have a problem that would otherwise be survivable, is in a battery or switch failure. With my setup, a battery or switch failure would at least leave you with two control surfaces on either side of the aircraft that would function correctly in both pitch and roll - although at decreased rates. There is of course additional cost there, about $200 with the receiver, switch and battery accounted for, but its cheap insurance for a $5000 model, in my opinion. It does not help you in the case of strong interference that overpowers your transmitted signal, but I can't really think of anything that really helps you there!

I do think though that a club (especially one that is full of non-jet flyers) dictating what you are allowed to fly is total BS though. MOST 'Roos (and most other jets) fly with one receiver and do just fine. I did the above modifications for my OWN benefit, to protect my plane, not for any perceived safety issues for spectators. Remember, the most recent fatality in the US was caused by a small, slow prop. plane, not a jet...

Bob

Thanks Bob

2 recievers is probably a much better solution. One of the recievers doesn`t have to have as many channels as the other.

I think Ill do this.....

SJN,

I think it adds some safety. I split the other channels too to spread out the electrical load.

One receiver operates-

outboard elevons
left rudder
nose wheel servo
airbrake servo
brake servo
retract servo

The other operates-

inboard elevons
right rudder
throttle (to ECU)
aux. engine control (also to ECU)

That way, if I loose the receiver that controls the engine, the ECU will shut it down.

Bob

sounds good to me....
I wil set mine up exactly the same way.

silly question....where do you have both antennas ?

Actually, not a silly question at all. The IMAC guys run two receivers in their high dollar acrobatic planes all the time for the same type of redundancy and power dividing. They advocate placing the two antennas away from each other and at 90 degrees, if possible. This is not to keep one receiver from interfering with another, but to help the setup be more immune to noise. The theory is, with the two antennas separated and at 90 degrees, a noise source that is interfering with one is less likely to interfere with the other.

That being said, they have much more room for antennas in their 30% - 50% Extras, Caps, etc. that they fly then we do in the jets. On my 'Roo, the antennas are in the same tube that goes from the receivers, which are just behind the nose gear well, back to the wing opening, and out into the wing. The tube sticks out the side of the fuse when the wing is off, but that's not a big deal since its flexible. The two antennas are routed together because this is the only route I could find that is away both from the ECU and engine controls/battery, and the long servo extensions back to the rudders and elevons (which go out the back of the wing opening - the antennas go out the front). That to me seemed more important than having the antennas separate and at 90 degrees to each other. I get over 200' of ground range with the antenna collapsed on my 8UHS with the engine running or off, and I have never had the slightest radio hit (knock on wood!)

Bob

I would be madder than heck at these non-jet goofballs dictating how you set up your Roo. Use the elevon mixing on two channels only, Y'ed to the left and wing servos, install some fake connection to two other receiver outputs. Lie to the boneheads. Tell them you set it up like they wanted and go fly. Be sure to have fun!

Yea......well I cant do anything about it.

These guys are "gods" at the field......


SJ.

You can do something.... follow my suggestion! And become a god!

For a person who doesn't believe in one (God), how can you tell someone to become one?

Woketmans a Rocket scientist, he only believe's in science!

Richard Newman

Hence the lower case "g".

I bet this thread is headed towards the trash / closed bin!