n8zb

I am a beginning RC flyer and I bought a T-Hawk at the recommendation of some friends and based on what I had read on the internet.

I am not doing real well at learning to fly this plane. I have had some hard crashes and have had to do numerous repairs.

I am flying the silkwind 400 on FMS and I think that is helping me with my over controlling problem.

But now to my questions:

I broke the tail boom at the slots where the control rods came out. After a couple repairs, which rebroke quite easily, I ended up shortening the boom by about 4 inches and reattaching the tail. I've had it in the air since then and the repair is holding OK but the plane is still difficult to control. What consequences of shortening the tail boom should I have expected?

Pusher prop airplanes throw a stiff breeze out the back a full throttle. Does this exaggerate the sensitivity of the rudder/elevators as compared to running a slow throttle? Are front prop airplanes easier to control because of this?

The instruction do not specify a proper C.G. Someone told me that it general it should be in the first 1/3 of the wing and it is. Any comments or more specific recommendations?

The plane seems to aggressively want to climb and stall. Could this be poor C.G. setting? short boom created problem? or just my pilot error?

Also when turning the plane wants to slip in and dive. I try to compensate by giving it a little up elevator while turning and it helps. Learned this on simulator. Can this be trimmed out in some manner or is it just a normal thing I have to accept?

I read a comment somewhere that suggested raising the wing at the rear with a popsicle stick. Would this help with my control sensitivity problem or make it worse?

I have trouble hand launching the plane alone. Tossing the plane with my left hand and quickly trying to get control and get the plane to climb before it goes to the ground is a problem. When someone else launches the plane things work a lot better. Any solution to this?

Thanks for reading and I appreciate any suggestions you may have.

Bob

aaronford

Lotta questions, but I am in the same boat. Yeah, the T-hawk is a handful. Too much for a beginner, I feel. I am buying a Slow Stick to try to fly something a little slower. However, you talk about the airplane being pitchy. Make sure that the electronics are secured with the 2 way tape and make sure your battery is secure. I have replaced the foam behind the battery with styrofoam from a stack of plates cut in the proper shape. It sounds like your CG is off. The battery should be so far foward the canopy may not shut properly. That helps move the CG back behind the leading edge of the wing. Remove the wing, but leave the battery. Hold the airplane with one finger hooked toward the canopy where the wing would be. It should slightly lean to the rear. As far as the repair, I think shortening the tail boom would make it a little harder to fly. I have considered using a carbon fiber archery arrow and lengthening mine a few inches for stability. You can repair elevators with clear packing tape and wings (they fold just past the reinforcement) with a small slat of woood. I made mine with a table saw and a sander. I extended it out to 22.5 inches to cover the fold. You can download the T-hawk for FMS off of the internet. On FMS, it is pitchy and tail heavy, so the guy that wrote the program must have flown one before. The papers I got with the airplane said to throw the airplane up at a 45 degree angle. It stalls every time. Try throwing it straight but let go before you pull the airplane down. With full throttle the plane should fly straight ahead for 50+ feet before controls are needed. Make sure to apply the throttle first as it will twist into the ground if done too late. Slip in and dive is normal, fighting that myself. I found FMS after crashing 20+ times. I think it will help my next outing. Gonna try that popsicle trick...

n8zb

Well I flew again last night with much more success. Still having some problems getting it up in the air, but once flying it seems better.

I reduced the control sensitivity on the rudder by moving the control rod from middle to end hole on the horn. I tried reducing elevator sensitivity in the same way but then I could not get sufficient climb out at the beginning so it is now back to the middle.

I am having someone do the hand launches and it does seem to be critical as to technique. The launcher has to take a couple of trot steps, hold the plane high, launch at an up angle of about 30 deg. with good speed but not like throwing a baseball. The pilot must give the plane full throttle and full up elevator.

Most important the plane must be launched perfectly level. The launch combination of slow airspeed (little air on wings dihedral to keep in level) an high prop wash on the full up elevator makes the plane turn toward the low wing side if the plane isn't level.

As soon as the plane picks up a little speed you can take out some of the up elevator and climb out nicely. Once up 30-50 ft you can trottle back a little and start slow turns. Turning at mid throttle with just a little up elevator is smooth and nice. High throttle maneuvers are touchy. If you shut down the motor and glide the controls are actually quite numb and take lots of input.

This confirms to me the complex relationship between prop speed, air speed, and control sensitivity. What I don't know is how much worse pusher prop planes are in this regard as compared to conventional front prop plane. Any comments?

BTW the manual does recommend beginners start with take offs from ground. I wonder if this is the reason, in that reasonable roll on the ground would get some air speed for the wings and assure a level launch.

Bob

aaronford

It's good that you figured out how to launch. Mine launches with a straight and level throw. If I try to throw it up, it loses speed/lift and falls. Half the time I could recover it, but since I was shown how to do a level launch it has worked much better. I originally was taking off from the ground, but I oiled the axles and the wheels fell off on the first takeoff. I guess the oil got into the white retainer and loosened it. I found one, so I will need new landing gear. I forgot about relaxing the rudder/elevator controls. I did that my second time out and it really helps my overcorrecting. I am still having problems with reversing elevator controls when I reverse rudder controls. I cannot seem to seperate the two. FMS is helping though. Did you get the T-hawk model for your FMS? Try here. http://gunnerson.homestead.com/files/fms_models.htm I am not sure about the prop wash theory. It makes sense. I also suspect that yours being shorter has a little more influence than mine. At least, til I break my tail boom....

jworosylo

This was my first airplane. i am now learning with a Xtra Easy 2 glow trainer. I dont have an instructor so i'm learning as i go. As for simplicity, i think the T-Hawk was the easiest plane to learn on. It always wants to fly, not fall, and repairing is simple, mostly because you can buy spare parts for almost nothing.... compared to everything else. Taking it off from the ground is a bad idea unless you have a paved surface, the gear will not last long because you always have to bend it back after landing, and bending it too much creates weaknesses in the structure. Next, shortening the boom is a bad idea, the flight characteristics will be basically shot to hell .... i suggest just springing for a new one, i know its relatively cheap, and flying it the way it was meant to be flown. Next, when it is fully assembled, make sure that when it is in the neutral position that all surfaces are squared up to thier respective surfaces.... if you need to, move the control rods to a different hole or bend them so that they work ... that is why they have that arch in them..... this will alow you the ability to trim than plane with actual results.... Next, always be sure to use full throttle when launching your plane.... i recommend lauching at an angle of about 10 degrees with your elevator trimmed slightly up .... then once you are up you can trim it back ..... then once you are in the air, you can decrease throttle to about half so that it is easier to control ........ remember to always fly this plane in winds less than 5 mph .. because it is very difficult to fly in any kind of wind, trust me, i know first hand... once you get better, then you can fly whenever you want....... if you have an direct questions, just PM me ......

aaronford

I checked out your theory that the prop affects the tail control surfaces. If you run the motor while holding the plane in hand, you will notice that it will rotate in whichever direction you turn the rudder. I can see this making it a little touchy. It does not seem to affect the elevator, though. I am currently having problems with my motor flexing up and down, throwing props, and braking motor mount plates. I am going to try rotating the motor 90 degrees to help limit this. We will see if it works! Aaron

PS Slow tick purchase was delayed due to purchase of paint sprayer. Practicality wins again.... Dammit...

n8zb

Regarding T-Hawk motor flex.

I had that problem too after some crashes I noticed that the motor mounting place, the black disk, looked warped/bent. The plastic it fastens to was also somewhat smushed. Motor could flex if you pushed on it thru the top access.

If you look at the fuselage along side of the motor you can see molded in bosses to support the motor left and right. I poked holes in the fuselage above and below one of these bosses near the middle of the motor with my hobby knife. I ran cable tie wraps thru them. I had to use two and connect them together but one long one would work OK. When tightened up they supported the motor on top and bottom and pulled the bosses firmly on to the motor. Feels real solid now.

Bob

PS I did get and install the T-Hawk model into FMS. Flys great. Wish I could fly the plane as well as I am flying the simulator.

aaronford

I will try your method of suporting the motor. Sounds a lot less intrusive than mine. I also noticed that the fuselage has to flex out for the prop to touch the body during crashes. A Zip tie would limit that.

I agree, I am a bloody ace on the Sim Tried to take my confidence to the field, but I let my father in law fly first. He crashed. Back to the repair shop. Oh well, it was worth it. This is the man that would kindly tap you on the shoulder and ask you to move the car, if it were on his foot. You ought to see him flying, though. Different person.