basimpsn

My Feedback: (5)

Ok guy's last October I celebrate my T-33 landing by doing a Cartwheel. Wasn't pretty.. I was convinced I need a complete fuse until I consult with another modeler and got his advice on how to do the repairs. So here is my repair process so far. Any new advice for the Re-maiden? I already know why it cartwheeled but during the landing I ran out of Elevator just before touch down and from the looks of my landing speed..I didn't stall it. So my question to guys flying this Jet (and willing to help)..what's your final CG location, did you use full flaps on landing..any advice will be appreciated.

Thanks

P.S I had about 3 flights on her before the crash, during flight this jet is rock solid. But during landing with gears down and take off flaps only..I'm loosing elevator
authority. (I don't pretend I know everthing that's why I'm asking for advice)

https://www.youtube.com/watch?v=Jsth...KveP2hFdE9VOQg
https://www.youtube.com/watch?v=sG9CPVRzypw
https://www.youtube.com/watch?v=1Mpx...t=HL1386254586

Paint Job by
http://www.garybestkustumz.com/gary_best.html

Vincent

My Feedback: (61)

Classic mistake with a jet is touch down on the nose wheel first. After that you become a spectator. It would have been nice to see more of the approach and set up speed for landing but it appears you did not have everything dialed in on final and kind of forced it down. What motor are you running and how heavy is it??
Thanks,
Vin...

basimpsn

My Feedback: (5)

Hi Vincent
My first thought after the crash was a CG problem because this T-33 refuse to maintain a AOA landing configuration on final (I have flaps mix with some up elevator), then I saw another video of a T-33 doing the same thing.

Power K-180 and weight is 41 # but nose weight for CG (4)#

.

David Searles

My Feedback: (49)

Basimpson,

Actually, you did stall. Stall speed is directly correlated to your AOA at that airspeed. When you pulled up after the first bounce you exceeded that AOA.

Your jet seems to be a bit nose heavy, hence your running out of elevator. Especially for scale jets, such as the T-33, you need to get into the practice of using throttle as your primary input on landing instead of elevator. It seems counterintuitive, but what you really needed to save that landing was a bit more throttle/airspeed to help keep the nose up.

Once you establish your AOA on final, you control descent rate with throttle, not elevator input. Elevator should only be used for the final flare just before touchdown.

David S

I just watched the onboard video, nice extension speedon the retracts! Must be electric. The video clearly shows that the jet is nose heavy. As you made the turn onto final every time you got the nose up it would immediately drop down again. Sort of a porpoising motion. You never got the jet properly set up with a positive AOA for landing. Jets that are slightly nose heavy groove quite well at higherairspeeds in full flight. The problems occur when you try to slow down for landing, as you found out.

rhklenke

My Feedback: (24)

Based on my experience (maybe 20 flights or so) on a BVM T-33, if this T-33 is anywhere similar, then you really were a spectator at that point. The T-33 (BVM one anyway) has more of a tendency to bounce unless landed (fairly gently) on the mains than any other jet I have flown with the possible exception of the PCM L-1011. In addition, when it starts bouncing, you're generally so slow that there's no more elevator effectiveness so there's no way to "re-flare" and get the attitude correct. The usual outcome is a gear repair - best case...

Your only option after the bounce, and its not exactly a good one, is to nail the throttle and go around to try it again. Even then, there's still a chance that you'll wind up with a cartwheeled (or de-wheeled) jet sitting on the runway with an engine screaming at full throttle.

I think David is right - you're still nose heavy, especially if you truly ran out of elevator on landing - i.e., the stick was *all* the way back, and you're at, or over, the recommended elevator throw. If you can get more throw, it might be worth trying to get it setup that way.

Another thing that is being discussed in the Comp ARF Hawk thread is actually reducing the amount of expo on the elevator stick to give you a more connected feel to the elevator as slow speeds. That could be setup on a "flight mode" for landing when the speed is slower and the aircraft response is reduced by the flaps and gear being out, etc.

Bob

basimpsn

My Feedback: (5)

"When you pulled up after the first bounce you exceeded that AOA"

Come on.. why would I pull up. As Vincent state after the first bonce..I was just a spectator. I do think it's nose heavy and I would need some info before playing with CG.

basimpsn

My Feedback: (5)

Rhklenke I was thinking the same thing about my Expo and elevator. On my maiden flight I was on low rate elevator until its time to land..I remember calling for high rate elevator with up trim so you may have a point there. Someone suggest soften the nose spring and adjust the CG Aft.

Going back to this youtube video you could see I'm having a little trouble with the landing setup.

https://www.youtube.com/watch?v=LNLy2o5d60s

David Searles

My Feedback: (49)

Human nature. But, okay, The first bounce caused you to exceed the AOA for that airspeed. My point is, the jet did stall, from lack of airspeed.

The best way to find the correct cg for your jet is to start slightly nose heavy, then start to do test flights moving it back, 1/4 to 1/2 inch at a time, until you find the best spot for your flying style and ability. That spot can vary quite a bit from pilot to pilot. The jet will give you all the info you need.

David S

basimpsn

My Feedback: (5)

Thanks David for your input.. I'm hoping the first adjustment works great are else I'm back to rebuilding a t-33 nose

mick15

I’m not going to tell you what to do I’ll tell you what I have learnt from flying the FB Jets one for three and a half years. This experience has cost landing gear, three sets of nose bearers and one set of main mounts, this aeroplane is without doubt a challenge to land. Bear in mind the FEJ is slightly smaller than the FB one.

My CG is 220mm from where the wing meets the fuz, I have 85degrees of landing flap, coupled with this flap I have ½” of crow (up aileron) I also have ¼” of elevator down trim. This elevator works on the assumption it is more comfortable to “hold” a model off rather than push down if it balloons!

My landing begins with a take off flap pass where the gear is lowered, full flap is applied at the end of the down wind leg, at this point the model requires at least ¾ throttle just to keep it flying! On final approach the speed brake is applied, it should become apparent at this point you are striving for as much drag as is practical. Once the glide slope is established you should adjust the touchdown point with the throttle, any control deflection will unsettle the glide path.

Too many people look upon the landing as the end of the flight rather than a very challenging manouvre, to keep the expense of each flight to a minimum practice landings!

M

http://youtu.be/s7OOQjTs52Y

Ozmodeller

Noticed that you have said that you have elevator up trim with flaps deployed, should this not be down elevator trim or is it a typo?

Peter

basimpsn

My Feedback: (5)

Mick15 very nice flying

Ok what I do notice about your landing, you can hold a AOA flare before touch down (that's how it should be) and your flaps need down elevator trim mix to keep your nose down, if that's not only for FB T-33 jets? Then some thing is seriously wrong with my setup. My FEj T-33 need lot's of up trim with only take off flaps. With that data..I'm really nose heavy.

Thanks for you input man.

basimpsn

My Feedback: (5)

No it's not a Typo..this is what going on during landing.. Flaps and gear down, my nose drop, so I trim some up, but know I'm fighting a high sink rate and you can see it in these videos it looks like i'm pushing down to lose altitude but i'm actually flaring up.

http://www.youtube.com/watch?v=LNLy2...eature=mh_lolz

http://www.youtube.com/watch?v=sG9CP...t=HL1386266520

mick15

Yes, well I think it is probably nose heavy. I had the supreme misfortune to be saddled with an early 1/7th scale FEJ F15e what I pile of junk! The reason I'm telling you this is their CG recommendation was 190mm! At that setting I was lucky to survive the maiden flight. The final setting was 235mm quite a difference.

m

mick15

In response to your post 13,,,,,,,,,,,,,it may be you are trying to fly the model too slowly??

m

basimpsn

My Feedback: (5)

"CG recommendation was 190mm! At that setting I was lucky to survive the maiden flight. The final setting was 235mm quite a difference"

That's a BIG difference In CG location.. The first video was the Maiden flight @ a small airfield so I have to drag it in with power any fastest would put me in the trees tops lol.
Now I have to play with the CG and hope that fix my problem.

Thanks again man

redtail

My Feedback: (15)

Hey Basil,
It's Chic, I am now working on my jet. Not ready to fly alongside you yet but I'll get there. Sorry to hear and see what happen to the T-33. Your repair looks good. Is the fella in Wardorf doing the painting? Is he making painting our models a part of his business? Stay well my friend. Chic

mario tavarez14

My Feedback: (37)

https://www.youtube.com/watch?v=5cyU...e_gdata_player

Here is the video of the fej t-33 crash

sidgates

My Feedback: (2)

Simpsn,
You have my sympathy concerning your crash but pleased to see the repair. I have approx. 200 hours in full scale T-33 and 'HAD' a BVM T-33. Your crash video is the classic T-33 nose gear touch first then porpoise. In full scale we were warned to never touch the nose wheel first but if you do the only way to save it is full power immediately. In your case the plane stalled right after the second nose wheel touch. I am puzzled by your need for up trim with flaps. Normally flaps down and/or speed brakes cause a pitch up on a T-33.

In the "maiden" video I noticed you were able to hold the nose off till mains touched. It didn't appear that you are at a much higher air speed. I plan to get another T-33, in the mean time I have a scratch built F-94C to maiden.

cactusflyer

My Feedback: (4)

Call me crazy, but my money is on TAILHEAVY. It definitely stalled after the bounce. If you look at the video, there is down elevator as it passes the camera, then the pogo maneuver. Aft CG caused it to continue to a high AOA. In the video you can see UP elevator, then down with no effect.....you were just a spectator at that point. The bird is unstable in pitch due to the aft CG. The reason why the nose drops with flaps is because the drag slows the plane down.....it is flying too slow. Once below trimmed airspeed, the nose has to drop or thrust needs to be increased to recover.....when you add flaps, add power....every time. On my A7, I dorked it on the third flight. It looked just like your crash, only I got it all the way on its back! I set up a bad approach and I was high and a little fast, so instead of going around, I decided to force it on.....BAD IDEA! Well, the down elevator gave me wheel brakes ON and when the mains touched, it was fast and it slammed the nose down hard and rebounded nose high. I didnt go to full power fast enough and it snapped and slid upside down in the gravel.....After the re-build and 300 flights later, the CG is well forward and lands nicely......very scale-like. After the re-build, I also made the nose gear spring very soft. If I slam it on, the nose stays down with no pogo action. I know it seems like apples and oranges, but you crash looks just like mine even though they are very different airplanes

Tailwinds,

John

basimpsn

My Feedback: (5)

What you waiting for Chic? I'm a lonely Jet guy at PGRC lol..But yes Gary did the paint Job on her and she looks great..hope I have better luck next time.

basimpsn

My Feedback: (5)

Sidgates

200 Hours in the real thing that's cool man..Im glad this wasn't real lol.. Well it seems my nose down pitch with 1/2 flaps is the main problem... All other Brand T-33 is the opposite I think..another clue.. I can't find anyboby flying the FEJ T-33(I know i know FEJ is bad other brands good lol) As for going around..the flight line was close to the landing threshold and you can only see the back of the jet before touch down, so I'm not saying I didn't relax my back pressure but what happen next caught me by surprise.


P.S I also flew my S/M F-18C the same day without a problem because I could bring her in and hold a little nose high until she settle on the mains. So I know there is something wrong with my T-33

Cactusflyer

You're saying it's tailheavy.. interesting..I hope someone who have the same FEJ T-33 Jet would chime in

sidgates

My Feedback: (2)

Simpsn,
I forgot to mention in last post that it appeared your speed brakes were open or partially open on takeoff. I always retract the speed brake before take off roll is started.

basimpsn

My Feedback: (5)

I think I must have blown a airline during startup.

I'll take this time to say thanks for all your input..Its obvious I have some CG problem and I will post the outcome of my test flight.

Thanks guys

rcavi8ter

My Feedback: (19)

Mick, Is you 22mm CG empty?