BobCat Elevators
 

Since we're talking about gyros---What are your thoughts on the JR NEJ 3000 gyro??? I'm thinking about using this gyro in a Sabre I'm building as I have one lying around not being used. This gyro used to be the top of the line JR gyro until the 5000 came out. What do you guys think?????

Kevin


PS---The 5000 is a head holding gyro....The 3000 is not.

BobCat Elevators
 

Last month I asked the tech at Horizon who was working on my trans. about the JR 460 "problem." He stated that he had NOT heard of any "problems" with the 460. When I described what I had been hearing, he dismissed it as typical internet rumor. He said he uses the 460 in his planes.

My 460 still seems to run just fine (knock on wood)

Mike Jensen

BobCat Elevators
 

Mike,
With the confirmed loss of at least 2 Bobcats to a 460T gyro and almost loosing mine from the very same gyro why would you want to take the chance?

Todd

BobCat Elevators
 

Good question! Did not really follow that thread. I was too busy on a new project and a new house to think about the bobcat gyro thing. The new one (a Mig) does not have a gyro. Not sure they are worth the risk. I think I'll just go back to flying the Bobcat w/o a gyro. It worked fine for the first 5 flights before I installed it.

Thanks

Mike

BobCat Elevators
 

I have somewhere around 300 flights on my Bobcat, several different gyros, and several different servos on the rudders. The last 200 flights have been with the third 460t gyro and have been flawless. If you test the gyro throughly using a hairdryer as a heat source you should with no thermal drift you should be ok. That being said if I were building another Bobcat right now I would install a Futaba gyro in it.

BTW when the gyros went out on my Bobcat It never exhibited the tendency to snap on me. It yawed very hard to the direction it failed, in every case to the right (I had 4 different gyros fail.) Full deflection of the surface. Must be my superior piloting skills though.....:rolleyes:

BobCat Elevators
 

Were ther any bleachers on the right as the Bobcat tried to pull to the right?

Mike Jensen

this is for DC1163
 

For the record, I lost my BobCat XL with elevator non-response (failsafe hold, I guess) a few weeks back - seemed to be having the same problems with elevator response that you are. I was having problems sometimes getting it to respond to elevator commands using the recommended 3301's - it would act like I had switched to low-low rate on the elevators when I hadn't done anything. I wasn't able to completely isolate EXACTLY when it happened, but it seemed to be fairly random and seemed to sometimes happen when I did a low pass (1/2 throttle or so) and started pulling up into a pretty tight turn at the end of the runway while going to full power for climb out (I had a P120 on the BC). Sometimes it seemed to be slow coming around in a tight level turn at altitude, but I kept thinking it was a speed related thing. The BC acted like I only had about 1/3 to 1/2 my normal elevator throw and was so slow coming around I almost bent the elevator stick pulling so hard on it each time it happened. I found that if I backed off the power, it would come on around faster - almost like I was getting elevator blowback which shouldn't have happened using the digital servos. I never did figure out what was happening, so I changed the 3301's out for 9411's for more holding power and torque - just in case I was getting blowback. On the first flight with the new elevator servos, I was about half way through the flight and decided to do a 1/2 throttle, low pass down the runway - like I did before when I had the elevator problem. I lined the airplane up with the runway centerline, let it descend gently to about head height, and when I pulled elevator to level it, NO response - I had NO elevator. In about 1/2 second the BC splattered flat on the runway and self destructed - there was absolutely no indication of an elevator problem prior to the crash. The only real damage was the airframe (all my hardward survived unscathed - thank goodness my gear was retracted and the BC hit pretty flat) but the engine got really hurt. The radio (TX, RX, flight pack, and 9411's) were sent to JR for a complete go through, and everything else was checked thoroughly. Horizon changed the servo gears on one 9411, found a broken antenna wire on the RX (we don't know if it was pre or post crash damage) and pronounced the radio to be perfect after repairs and a checkout. The battery was a 4 cell 1400 mah and was cycled regularly. It cycled just fine after the crash, but JR checked it out also. I'm still flying the radio and RX, and so far haven't had any glitches, but still am not comfortable with the final lockout I got while flying the BC - AND I STILL don't know why it was so slow to respond to elevator commands sometimes. Sure makes me nervous about building and flying another jet (but I'm still working on another one anyway)!!

Hope someone else might shed some light on this issue.

Wish me luck.

Regards, Les

BobCat Elevators
 

About two weeks ago I asked a question regarding unequal elevator travel. Here is the follow-up. After trying a number of different progamming tricks (nothing worked) I discovered that some of the horns were loose. I then redid all of them. Still no success in getting the elevator halves to track together. Finally I realized that one of the halves would not move all the way though its range of motion. After fixing this the elevators now travel in near perfect synch even with just a Y-harness. Sometimes I'm just dumber than I think I am!

BobCat Elevators
 

PS Does anyone know where to get small air tanks- the ones that are only about 3 inches long?

BobCat Elevators
 

SpringAir!

www.retracts.com

Todd

9411's
 

I can't find them. Horizon doesn't even list it. Can someone point me in the right direction?

George

Loss of elevator control
 

Interesting comments about the Les' BobCat. I lost a HotSpot about 2 years ago with identical findings. 2 flights before the crash, elevator commands seemed to be getting soft coming out of loops or reverse cubans. Then on the final flight, after a high speed pass and pullup and 45 deg downline on downwind, no elevator. No bobbing, rolling, pitching....nothing. Went straight in at 45 deg down. It had 8411's on the elevons.

Battery was salvaged and check O.K. Heavy Duty JR switch got trashed, but still functioned. Plane had over 225 flights. 8411's were fairly new, having replaced older 4721's about 50 flights before the crash. Both servos were stripped, but after replacing the gears, worked fine. RX was junk.

My final impression was I lost power to the elevator servos. I was wondering whether a long term high current going to the servos fried the output to the elevon channels, but why both at the same time, or just lost power to everything, but why the soft elevator on the 2 previous flights?

Tom

BobCat Elevators
 

George, Horizon doesn't list them with the number. It's listed under "mid digital". Here's the link though

http://horizon.hobbyshopnow.com/prod...rod=JRPSDS9411

Try Chief Aircraft though, they will probably be cheaper.

http://www.chiefaircraft.com/

Bob

BobCat Elevators
 

Thanks Bob.

Air Tank
 

Roger

Call Dan at Cedar Park Hobbies in Austin. They have the small Spring Air tanks in stock. At least they had some yesterday.

512-331-2943

BobCat Elevators
 

Thanks Bob. I will.