HI TO EVERYBODY!

HERE IS MY NEW ROO I WITH P80 . I HAVE FLOWN THE MODEL APROX 20 FLIGHTS AND FLYES SO GOOD, BUT I HAVE A LOT OF PROBLEMS HANDLING THE AIRPLANE IN THE GROUND. THE AIRPLANE IS VERY UNSTABLE AND IS REALLY DIFICULT TO LEAD THE AIRPLANE STRAIGHT, SPECIALLY ON THE TAKE OFF RUN. I TRIM THE AIRPLANE ON THE GROUND AT A MEDIUM SPEED BUT AFTER IN THE TAKE OFF RUN AT HIGH SPEED THE MODELS ALWAYS GOES TO THE RIGHT!!! AND SOMETIMES THE AIRPLANES TURNS UNSTABLE AND THE RIGHT WING HIT THE GROUND AND I HAVE TO ABORT THE TAKE OFF. I HAVE TRY DIFFERENT STRUTS (ROBARTS, EUROKIT, MY OWN ONE DESIGN ) AND WHEELS (EUROKIT AND INTAIRCO) BUT WITH NO RESULTS. I HAVE ALSO TRY A GYRO BUT WITH NOT VERY GOOD RESULTS.[]

CAN ANYBODY WITH ROO EXPERIENCE HELPS ME AND GIVE ME SOME EXPLANATION AND RECOMENDATIONS ABOUT WHAT IS HAPPENING AND HOW CAN I SOLVE THE PROBLEM?

I ALSO HAVE A SKYJET (ALL COMPOSITE) WITH P120 _NO PROBLEMS AT ALL AND GREAT JET TRAINER. I HARDLY RECOMMEND TO THE BEGINNERS!!![8D]

THANKS AND REGRADS FRON SPAIN

COQUI

Make sure you have a couple of degrees of toe in on the main tires.

Make sure you have no slop in your nose gear steering.

I always used low rate rudder on take off which allowed the nose tire to move very little.

Hold full up elevator (to keep the nose light) and slowly pour coal to it. It would track straight down the runway.

Regarards

Ben

COQUI, Gary is on the money, set up your Roo's rudder on low rate for take off and landing with minimal left/ right steering deflection and high rate use for taxi only. Or set rudder expotential so you have minimal movement around center stick, you should not need a gyro at all on the Roo IMHO. Also a tip when landing, as soon as you touch down stay off the up elevator altogether as ground effect will hold model down very well.... Landing the Roo consistently without any 'Roo' bounce should be the only thing that takes a bit of practice. All things being equal during take off roll and if using above guidelines you should have 'No Worries'

P.S. I also have a SkyJet and just love it.... Have you had any problems slowing it down for landing

Add "expo" to your rudder to "soften" your steering [8D]

Don't over tighen your pull-pull steering cables,
if too tight the retract will not lock in and will give way after landing[:@]

And when all that works or doesn't work, put a $60.00 gyro on it from tower hobbies, leave the expo out, put full travel on your steering and be done with it!!

Placing a gyro on the steering with track your jet straight down the runway every time no ifs ands or butts about it.

No need for rates or expo.

Sean

I had the exactsame problem as you, tried all the tricks even the best gyro and still no luck.

In a nutshel the problem with a ROO on take off is that the rear wheels get light and the plane has a tendency to rotate around the nose wheel. When the ROO was designed it was ment for a 12 pound thrust turbine, You have a lot more thrust now.

Here is my bullet proof set up for over 100 flights.

2 degree toe in in the main wheel

make sure you have the rear caster strut form Robart for the nose wheel

adjust nose wheel to about 5 degree left & right throw on take off.

ensure one of your brakes is not dragging more that the other AFTER you applied a full stop such as on an outbound taxi.

make sure you hold FULL UP ELEVATOR until the plane takes off and then adjust elevator for the climb out angle that you desire.

I also found that my take offs are a lot easier at 2/3 throttle than full throttle.

Good luck

Peter

I totally agree with Sean, I put about 15 flights on my Roo and keeping it straight on takeoff was the most difficult part of the flight. I took his advise and put a piezo gryo on and the last several takeoffs have been a piece of cake.

Marty:

Thanks for your recomendations. I will take care of all the tricks you have advise me. I will tell you the result.

In relation with My Skyjet. The jet flies perfect but the even with the FULL FLAPS EXTENDED I can not slow down the airplane so much for landing and the entry on the runway is very fast and I need too much runway for stop the airplane.

Have you install the Airbrake? In your photo do not looks like. In this case how you do for slow down the model?

Regards

Coqui

One other thing on landing, slow it way down with the air brake. This will eliminate the Kangaroo bounce.
I have almost 300 flights on mine and have used a JR gyro from early on. Makes it so easy.
I prefer full throttle take off's, because the full thrust holds the nose wheel firmly on the ground.
I have used a 17 and 25 lb thrust engines on mine. I prefer the 17 lb engine for ease of take off and especially landing.
Use 20 degrees caster on the nose wheel. Wheel should be behind the strut turning axis for stability.

Have fun,

Pete

coqui- re, SkyJet your correct I have not fitted the speedbrake as yet. I have about 12 flights on the model so far and all landings have been quite fast to say the least, I have the flaps set currently at approx 45 degree's at max deflection but I still want to try setting flaps to 90 degree deflection more like speed brakes and see if this does the trick. I hope to try this fix this comming weekend and will let you know if it helps?

Re- Roo Peter also made some good suggestions, check the main wheels and add slight toe in and check brakes are not dragging on one wheel.
I do wonder at times how some guy's ever managed before gyro's came onto the scene [sm=tongue.gif]

Marty:

My landings with SkyJet have been made also with 45º of Flaps. Please inform me about the landings with 90º and how slow down the jet, when you try this weekend.

I will "fight" with my Kangaroo to see the results of all you recomendation taking off.

Coqui

No need for the band-aid gyro. Follow the good advice above (toe-in, full up elevator on takeoff, lots of expose on nose wheel, etc). In hundreds or Roo takeof, I only went squirrly once, and that was cause I was not paying attention.

I agree. My Rookie is rock solid on take off when those things are done.

I'm with Wocket..... Real men dont use Gyros
Sean = Sissy [X(]

LOL, if that's close to the worst you can say about me, I guess I'm not doing too bad.

However, don't let these guys fool you. Many of them have used gyros. Even the great Johnny Hernandez has steering problems with his Mirage last November, I had an extra gyro on me, stuck it in his Jet and from what I understand, all his jets now have gyro's on the steering.

Can you live with out it? Sure, do all that crap above and you'll probably be ok. $60.00 is cheap insurance for never having to worry about it again.

Todd and Wocket = Technologically Inept. [sm=pirate.gif]

Sean, I personally do not own a gyro, nor have I ever used a gyro or felt the need to install one on any of my jets or prop models in over 30 years of R/C flying. By the way all my jet models are set up the same eg. hi-low rate on rudder/steering and they all work just fine for me. I find it funny (odd) that you are referring to basic model set up as 'crap' eg, main wheel castor angles, brake setup, duel rates and expo as mentioned previously are all model rigging '101' stuff. Why on earth spend $60 dollars ++ on a gyro that can 'possibly' create additional set up and operating complexity concerns especially on a Roo that does not need one??? Geez might as well install a full auto pilot system with GPS and sit back and watch while having a beer eh!

My friend!! I have told anyone who will listen to me that this is exactly what I've been waiting for!! My goal in this hobby from day one is to put a flight on my airplane, and refuel, hit the button and watch the airplane "redo" the flight using sytems as you describe! Drinking the beer is optional!

I'm totally into the electronics available to us right now! Listen, are you flying your jets with a Kraft Radio? Or should I take a jab that you're not flying Jetcat?

I've used Gyros, Flight stabilization systems, PCM, FM, whatever. The technology is there and it works! I put a gyro on my steering in my TMAXX off road truck. When I hit the brakes, it does not "veer" to one side. You can't duplicate that without a gyro.

Look, whatever, if you want to spend the time rigging, etc. I'll bet you use resins instead of aeropoxy to put your formers in? Are you still sheeting with Sorgum glue? There are advances in this hobby that make things easier. I can't help it if I believe in them and I see every time that I fly that they work.

I'm done defending gyro's. I guarantee my airplanes take off straiter than anyone else's. And bonus that if there is significant crosswind, my airplanes adjust accordingly and I don't even have to deal with it.

I'll still have that beer with you, EH!

My 2 cents worth!

Not too much slop in steering cable
Not too much power on take off
Not too much travel on steering(Dual rates for take off)
Toe in
Check angle of the motor - there were some mods requiring spacers under the motor to lessen the pressure on the nose wheel-the Rookie has dropped the motor and therefore the thrust angle down on the nose wheel is less - this is the biggest problem with the ROO, the high motor and if you increase the thrust, you increase the pressure on the front wheel which makes it more difficult to track)
Gyro is always an option-replacing the struts and wheels is a lot more expensive!

You're definitely not alone, just as the "Kangeroo landings" - ALL ROO pilots have had one or are going to have one

Good luck

Zane

To be serious here...... The one thing that I used to do that helped more than anything stated above, lock your brakes as you spool up, this loads the nose up heavily for the takeoff run (just watch you nose strut compress) giving better steering control.... along with very low steering rate and slight toe in I never had steering issues and No GYRO

Sean likes his planes to fly for him ...... I say just hand me the radio sissy

"You're killing me Smalls!"

'The Sandlot'

[sm=lol.gif]

Sean, whats wrong with Kraft radios? aeropox whats that? jetcat??? is that what you get after feeding your kitty some good Texas chilli??? I gotta agree with you though mate on one thing bring on da beers.....

Using a gyro in a Roo IMOHO tantamount to masking a minor problem that could be easily taken care of by some of the intelligent opinions given by some experienced pilots above.

If you use a gyro, make sure it is setup to off condition when the gear is retracted or you might end up with a nose gear that would not extend when you want to land (depending on the size of your nose gear cutout).

Finally, a gyro that you could not turn off when the gears are retracted would also work your nose gear servo during flight.

With more than 700 flights on a Roo, I am speaking from experience and take it FWIW.

If I may borrow what MOROCCO told PORTIA from the unabridged version of The Merchant of Venice

All that glitters is not gold;
Often have you heard that told:
Many a man his life hath sold
But my outside to behold:
Gilded tombs do worms enfold.
Had you been as wise as bold,
Young in limbs, in judgment old,
Your answer had not been inscroll'd:
Fare you well; your suit is cold.
Cold, indeed; and labour lost:


With regards to your other airplane landing fast, have you considered using crow? My TGA Interceptor use to come in hot and I listened to an experienced pilot (Kevin Whitlow) with many turbine flights on Interceptor than any one else I could remember and added crow to my setup and the rest was history.

Secondly, check your CG and make sure you airplane is not nose heavy. A nose heavy airplane tends to land fast.

Finally, deploy your flaps/speed break on your downwind leg to help bleed-off the speed. Check your turbine idle speed to make sure that it was not setup higher than the recommended factory specifications as that would increase your residual thrust during landing.

Regards

Ben

Bend the nose strut offset back a bit so the tire is trailing. I am using a 3/8" robart offset strut on my rookie and it tracks perfect every time.
V..
ps: don`t need no stink`n gyro in this jet.