J_f_r65

Hello everyone,

I did my first flight with my New Rookie a few days ago. It was the worst flight I have ever seen...

Till today, I only could read positive feedback about this jet. But my flight was exactly the opposite !!! Unstable, nose heavy, extermely sensitive in the ailerons and the Airbrake was not functionning !
Everything was perfect for a crash landing. And it happens the way I though... a rebound with a hughe nose up followed with a 90 degree turn in direction and bank. And then impact ! Nose broken plus a few small other things. Lucky ! Could have been worth.

Now, I'm looking for an explanation. Can somebody please HELP me to find settings which are adequate for the New Rookie.

I did (at least I think I did) everything as it was written in the notice:

> CG: exactly at 130mm ahead of the front edge of the (main?) aluminium tube (a few centimetres ahead of the main landing gear…), landing gear down, hoper tank full and main tank empty. As written in the notice!

> Elevator was exactly set to be aligned with the trailing edge of the wing (logical or what?). Full trim up was not enough to maintain it horizontal at slow/middle speed.

> Canard was set to match with the marking of the fuselage ( how many degrees of angle of attack? ). after in flight trimming of the canard, I had approximately 3 to 4 degrees nose up.

> Thrust vector as near as possible of the 0 degree line of flight. ( I had no difference with or without thrust vector concerning nose up or down tendency…) So I switched it off for landing.

> Landing gear was down to be able to set the best trim for landing. (never found the right balance ??!!!)

> Take-Off Weight is 12.5 kg with 3,2 litres of fuel (ZFM is 10.1 Kg)

So what is wrong ? Why can I not find a stable attitude for landing without being forced to pull the stick (elevator) backward permanently (trim full back) ?

I thank you all for any advise helping me to find the right setting of the my Rookie.

Best Regards from Switzerland.
Jeff

Airforce7

My Feedback: (31)

How much travel do you have on your elevons? You should have at least 25-30mm of travel up/down for the elevator with some reflex (trim up) of about 5mm or so from the trailing edge. Why do you think your bottom side air brake did not work? Is this your first turbine jet, what turbine is installed? Can you share some pictures with us?

J_f_r65

Hello Airforce 7,

The Rookie is my second Jet. My first was a kind of Alphajet type (conventionnal wings and elevator with 2.2m span and 17.5 kg TOW.

The airbrake didn't work because the inner skin was ripped out at the first opening (low to middle speed, positive nose up attitude.). I have made some modifications.
The turbine is an AMT Pegasus (year 1997, with only 2 hours).

I have the 25 to 30mm of travel on the elevator and 20mm on the ailerons. I have also 15 to 20 mm travel on the canard. As said in the notice.
A friend of mine have a kangaroo and told me as well that is has more or less 4mm trim nose up on his elevator.
What you propose (5mm trim nose up), is it for take off and landing or during all phase of flight ?

So here are some pictures of my Rookie before the missed landing... and after...

Thanks for you help.
Regards.
Jeff

Thud_Driver

My Feedback: (1)

"What you propose (5mm trim nose up), is it for take off and landing or during all phase of flight?"

You need it all the time. It's more or less the neutral trim point for the airplane depending on your Cg & canard incidence. It's likely the reason you ran out of trim.

From your pics, you have an awful lot of stuff far forward in your fuselage. You may need to move it back unless your batteries offset it. Several Rookie II's that I've seen have needed the ECU battery back by the engine. The weight of the repairs won't help the Cg situation.

Just to second guess the situation, I would recheck the Cg at zero fuel and might even suggest you try it at 125mm.

LGM Graphix

My Feedback: (22)

I've never flown a rookie that wasn't already trimmed tested and flown, but my first jet was a Kangaroo and I needed about 3/16" of up elevator trim in the elevon's to maintain level flight. I've heard that the Rookies require this as well. Not sure why they wouldn't just mold the wing with enough reflex in it but that was my experience with the Kangaroo. Just a thought anyway

J_f_r65

Hi Thud driver,

Actually, all I have in the forward part of the cockpit is the DPSI Emcotec, the Rx Fut 6014 and two Magicboxes. No "heavy" stuffs...
The point is that my turbine (AMT Pegasus is almost 1 kg heavier than a Jetcat P-120. So I had to relocate almost every thing relatively forward.

My CG is (was before repair ) exactly at 130mm with Hoper tank full, gear down and main tank empty. That is the recommandation of ARF Composite.

I had already the "impression of instability" ( marked pitch up by every up correction, maybe due to a to great deflection of the canard?) with the CG at 130 ! And you think I should move it back to 125mm?

The repair will not move the CG very much as I first "dig" in the fuselage to take away all the gelcoat and glue before applying the new fiber.
But anyway, I will check the CG after completion of all the repair and move the Battery Packs backwards if necessary.

LGM Graphics,
You're right, I was asking myself the same question when I heard that we need about 5mm nose up trim.

But at least, everybody seems to be agreed on the fact that I have to trim my Rookie with 4 to 5 mm nose up.

Thanks.
Jeff

Thud_Driver

My Feedback: (1)

125mm takes some of the required pitch trim out of the elevons. You complained about it feeling nose heavy and running out of trim.

You haven't mentioned whether you used expo in the Tx. For me personally, I used around 40% expo (JR radio) on the elevons for both pitch & roll. I also used a curve mix into the canards to get the equivalent expo for the canards. In addition, while the canards were set to get about the throws you used, I limited them to 75% of that in the mix. All of this will give a softer feel and may take some of the "pitch up" sensitivity & trim issues out of the plane. Think of it as using the elevons for primary pitch control and canards to help a little until you sort the airplane out.

If you're not a fan of expo, and some people aren't, use high rates for takeoff and landing and dual rate pitch and roll to around 60-70% for up and away. You will want a lot of throw for landings.

Thud_Driver

My Feedback: (1)

Ok, I missed that you had thrust vectoring on for the flight. Really, you want that turned off for normal flying, particularly if you are flying at high power or mid to high speed. It's very effective, and, at least initally, you should plan to use it for lower speed high pitch rate maneuvers.

tahfiet

Hi Jeff!

Running out of up-trim and having a sensitive elevator i a bit curious. I did the first flights with my Harpoon with elevator trim on "zero". It does need some trimming with the canards and the thrust-vectoring. I am now flying with 2mm up-trim on the wing and a more nose-heavy C/G, which is just fine for high-speed.

With the Futaba T-14MZ I use 55-65% Expo to get the ame feeling as I had with my JR 10X with 35%. And you should try some 50% Expo on the Canard nd the thrust-vectorig as well, to make live easy for a start.

David

JetCatJimmy

Well, you get a thumbs up for the repair job. It looks very solid. Good luck on the next run and please continue this thread with your progress!

GreenAcre

My Feedback: (13)

The Rookie was my second jet and it fly great! I only had a 14lb turbine though. Wish I would have had MORE!

TUMBLER

My Feedback: (13)

man that looks familiar. My 2 buddies had the saaaaame problem. One guy fixed his nose and then it happened again. The other guy broke the nose, fixed it, but stipped it and bought somethign else. All 3 times, the plane touched down, pitched up, snapped and nosed in. So wierd.

I had over 100 flights ona Kangaroo, the predecessor to the Rookie II and never had this happen once. My only theory is that the canard gets lift under it on landing and makes it pitch up. One can only guess though, but seems strange it doesn;t happen to the kangaroo with the main difference being a shorter nose and no canard.

Sorry man.

Tumbler

Airforce7

My Feedback: (31)

Tumbler,

I had to change the nose gear strut spring in the Robart 630s I bought from Dreamworks to prevent the nose from bouncing up every time I landed. I used a much weaker spring that allowed the nose to absorb the touchdown. Also, if the nose weight isn't right and the spring is to strong, the nose will bounce and you will not be able to steer. All things I found out three years ago on my first flights with the Rookie II.

Ken

erbroens

I also have seen this typical maneuver, a Rookie lands in a "flat" attitude with too much speed, the long nose gear touches the ground first rotating the airplane nose hard up, making the plane stall and snap without control, usually landing on it´s back breaking the canopy and fins.

How to avoid this? land slowly, holding the rookie nose well high up as long as you can, touching ground with the main gears.



Enrique

J_f_r65

Thanks everybody,

It seems that the Rookie (2) is not the easiest airplane to land...

I finished the repair od the nose this afternoon.

I'm going to try new conditions. One for Take-Off and Landings, the second for normal / high speed and a third one for "future" 3 D or better said low to middle speed manoeuvring.

1) trim 4-5 mm nose up on elevator with 25 to 30mm throw. Canard set on the marking of the fuselage with a good expo. I have also to check the sevo speed you can change on the Futaba T12. And Vector on with about 15° nose Up/down. Expo about 50%.

Switching to condition 2 will be done with gear up.

2) I will reduce all the throw to more or less 70% of the TO / LDG throw. The canard to 50% and Vector off.

Then the 3 D mode will be more or less as the condition 1 with a little more canard and vector.

Generally, I will set the CG a little backward but not less than 125mm (which is also in the instruction manual of ARF-Comp)

Does it sound reasonnable ?

A few picks of the repair with a "cheap" painting as I'm not sure about my next landing...

Jeff

Airforce7

My Feedback: (31)

Repair job looks good Jeff. For the canards, you can program them to travel with the elevator. I flew mine active all the time with about 22mm up/down. Trailing edge of the canard goes down when the elevator trailing edge goes up. If you don't have the bottom speed brake fixed, then you can do two things to help slow the Rookie down. One is to turn the canards into a speed brake by setting the throw to 75-80 degrees trailing edge down. The canard should travel quickly to this position; there will be some pitch up initially. Second is to increase the thrust vectoring so that when you land the idle thrust is angled up. Be careful if you have to go around, turn the thrust vectoring off with a switch or gently ease back on the elevator stick during the climb. Hope you have success on your next flight.

GreenAcre

My Feedback: (13)

It not the easiest plane to land. I had to ease her in on alot of elevator and right when she almost touched down I was at full elevator. The mains first then the nose. Nice landings MOST of the time.

J_f_r65

Airforce 7,

The repair is 100gr. heavier than before, not to bad. I had to relocate 2 of the 3 batteries to the rear of the fuselage and take away the 100 gr weight I placed also in the back to achieve the CG. So all in all NEUTRAL !

I wanted to check the final position of my elevator just before the hard landing and it was actually as I set them before take-off ! Stange !
I checked the radio and on my big surprise, the elevator trim was at 0 ! And the throttle trim was at -50 !!!
My collegue who was helping me is flying the other mode, with the elevator on the right... So no wonder that I felt no change during the whole flight.
But at least I have one explanation to this strange behavior.

Well I will try to land the Rookie the way GreenAcre is doing but I think that we are not yet playing in the same category...

I will keep you advised.

Regards.
Jeff

Airforce7

My Feedback: (31)

Jeff,

You’re not alone, I added about half that amount of weight to the nose of my Rookie when I had a slight mishap a while back. I have always placed the turbine ECU battery right next to the turbine on the bay cover with Velcro. The Velcro strip was long enough to accommodate a larger battery or moving the stock battery further aft for balance.

Take the time to go through your radio and test all your settings, including trim, so that you know the surfaces will move in the right direction. I always do a ground check before a flight to be sure the control surfaces move in the correct direction. There was one instance that I had the jet in the start-up area ready to go when I turned on my transmitter and checked the elevons (originally ailerons and elevators) and they didn't look right. Turned out I plugged in the aileron servo to the elevator servo lead from the fuselage. Sad part was all the leads where labeled correctly, I accidently swapped them! []

Ken

high-flyer

Hi Jeff,
i had around 100 flights with my rookie 1 and have since sold the jet. After breaking the nose on the test flight i found the jet to be an excellent flyer. The first crash was due to some cheap rudder servos and a stessed out pilot. My advice is do not use the thrust vector at all untill you want to do 3D. Minimise canard movement and stick to the recomended CG and elevon movements. Landing involved airbrake on final and always hold up elevator to land on the mains. Once you learn what the rookie needs you will love it.
My first experience with the thrust vector went staight into a inverted flat spin. [Yahoo] I think my caller had a heart attack.
Best of Luck
john

J_f_r65

Hello again,

Last Thursday, I did once again, a "first" flight, hoping that, with what I could read from all of you, the settings would be ok !

And IT WAS !

3 Great flights. From low to high speed and finally to splendid landings ( on the mains...) on a grass runway.
The Rookie is an amazing Jet with incredible flight caracteristics.

I only 2 small problems with my main wheels which were bloqued on their axel (one after the other, during 2 different taxi). I had to take them off (with great difficulties) and clean the center of the axel of the wheels.
I think it has simply to do with the "new" material which needs to be formed.

I also have quite a large Turbine. The AMT Pegasus is one centimetre larger in the diametre than all the equivalent engine. Therefore, it is quite near to the top of the fuselage and it is getting VERY HOT. Today, I will cut the fiberglass to create aerations of the upper fuselage.

I'll keep you advised.
Best Regards.
Jeff

BaldEagel

J-f-r65

Reading your post is seems you have seperated the elevators and alilerons on the wing and are not using elevons, these should be combined as per the instructions and the reflex should have the elevons level with the top surface of the inner part of the wing attached to the fus, if you did not have this configeration the nose would want to pitch down all the time and you would run out of elevator trim as you are only moving two surfaces instead of all four on the wing, just an observation from your post.

Mike

seflyer

My Feedback: (12)

I never had any pitch problems or felt that it was overly sensitive, cg was at 130mm and trim on canards was around 5mm. it will fly approach and near walking speed.

Kevin

Dave Wilshere

I would say 100% it is because of the vector tube setting. I've seen this several times before.

I have had Rookies and Harpoon II models and theyare great aeroplanes and I think easy to land when you understand the model.
They are quite lightly loaded considering the wing/fuselage area.
Being a delta they must touch down slow enough not to be flying, so nose high and on the main wheels. This is easy with the Rookie when set correctly, you are only at full up on touch down. The stock AB is a little small so the model takes a long time to slow down, put the gear and AB out on the down wind leg in light winds and get the aeroplane slightly nose high all the way around the approach, as soon as the nose drops the speed builds up. On a long runway it's easy just hold the nose high and wait wait wait and it will eventually settle.
Forget gear down trimming, it is not needed, once the gear is down you want some back stick pressure to get the nose up anyways.

I set the vector nozzel on a dial pot channel for the first flight and trim the aeroplane with that (assuming correct C of G and canard angle-which sounds OK from what you are saying)

Regards

Dave Wilshere