Trex 250 build videos

[Finless]

Ooops sorry.... LINKS fixed...

Bob

[Bart101]

Thanks Bob...

[dxtarl]

Hey BOB can i have some CHEESE with my wine?

[misunderestim8]

Thanks for the videos!
I am looking forward to your tail build section as are many others I'm sure. I know that your going to build the 250 stock the first time around but it would be great to hear your recommendations on a tail servos perhaps during your flight video.

Thank you for your work. I never would have made it past opening the box of my first 450 with out your videos.

[knightofcarnage]

I really can't wait for bob tips on tail, Bob i hope you can some how squeeze in tail setups on lower end gyro (eg 401). I been trying to get the tail not to wag with the 401 for 2 months.
New tail hub , 3 new set of grips etc .... and still have WAG.

[cb3d]

Originally Posted by nightofcarnage

I really can't wait for bob tips on tail, Bob i hope you can some how squeeze in tail setups on lower end gyro (eg 401). I been trying to get the tail not to wag with the 401 for 2 months.
New tail hub , 3 new set of grips etc .... and still have WAG.

The 401 is hardly a low end gyro. I use them on all my helis except the 250 and thats only because it came with a good gyro already. If it hadnt I would probably be using a 401 on it as well. I have never used it on the 250 so I cant speak from personal experience but I have had great success on all my other helis with it and not to say you dont have your heli setup correctly mechanically, but it has been my experience in the past that if everything isnt spot on mechanically with the 401 you will get issues.

[Jasmine2501]

Originally Posted by nightofcarnage

I really can't wait for bob tips on tail, Bob i hope you can some how squeeze in tail setups on lower end gyro (eg 401). I been trying to get the tail not to wag with the 401 for 2 months.
New tail hub , 3 new set of grips etc .... and still have WAG.

Hmm... Futaba GY401? You've tried tail hub and grips, that must not be the problem... have you tried a different servo? Have you made sure your servo arm is small enough? Is the tail linkage straight? Did you try the metal tail shaft? Lube the bearings and shaft? Do you really have "wag" or is it "drift"? Have you tried the whole range of gain values?

[Schelli]

i think one of the most important things to get the tail fixed are

a) really make sure you have nothing binding at all
b) get a small wheel for the tail servo it can be as small as 4mm, some ppl even fly with shorter like 3.5 mm. if you are out at 7mm you will have a lot of difficulties getting the tail steady. just check how much travel your servo does from max one side to the other. it should at least be 45 degrees or the gyro might lack the resolution to do precise work. i think if i remember right the limit pod of your 401 should be some like 80-100.

i personally have the spartan ds760 and i am glad i have put in the extra few euros, cos the gyro is light and has an excellent performance. still, if you have the wrong setup on the tail you will have wag with this one too.

[knightofcarnage]

Jasmine, I tried DS420,S3153 right now i have 401 with G290. now i did lower the server arm travel from 9.5 mm to 7.2 (G290) and that help some. I will lower it more and see what happens.

[Jasmine2501]

Servo arm needs to be 5mm in order to get good resolution.

[knightofcarnage]

I set mine at 4.2 its much much better. However still can't get more then 18 gain (HH). BTW id did not notice anywhere in the manual mentioning the proper off set, only thing i found was on page 19 of the pdf. Now i do belive that the tail problems i was see where not from the hub but from resolution of the servo.

[Jasmine2501]

Bottom of pg 26 in the manual it says 5mm, but on the little insert for the gyro, it says 4.5mm.

On a better note, I turned up my ATV on rudder to 125%, and I'm getting a much better piro rate now, but it's nothing like what I've seen on some of the videos - with full stick it's just fast enough for a piro flip, which I suppose is fast enough, but others seem to be able to get it faster. Backwards flight and sideways flying are all working very nicely now - still using the stock stuff

[knightofcarnage]

My page 26 is Flight Adjustments and Settings. I think it depends on the kit you get , i did not have a combo with gyro. I just had the 3 cyclic servos. hmm. My manual is just like this one.
https://www.helifreak.com/showthread.php?t=102697

[Jasmine2501]

Strange, on pg19 in that manual is the same picture, but no measurement is listed. I suppose it could be different for other gyros or servos, and so they don't specify.

BTW, I can't get my gain very high without getting wag, but I don't think it's an issue. The way I understand gain, it doesn't make the gyro more sensitive, it only increases the reaction you get for a given sensor input... so the gyro is still seeing the angle changes with the same accuracy all the time, but the gain affects how much of a reaction you get. So I don't worry about the specific gain setting, as long as it's high enough to stop drift, and not high enough to cause wag. That's how I understand it anyway.

It makes sense, because the sensor inside the gyro can't really be made any more sensitive by adjustment - it vibrates at a certain rate and produces an acceleration signal with a certain magnitude - then the software applies gain to that and determines a reaction on the servo. It's kind of like how when you turn up the volume (gain) on your car radio, you don't make the radio signal any stronger, but the output is louder. I think that's how it works anyway - would be nice to know if that's correct... anybody?

[Evan T.]

well its gonna be cool the next time it rains at bobs place lol

[knightofcarnage]

Jasmine,
I think high gain translates to fast sampling rate in the firmware (that is my guess) which will send more frames to the servo.

[DaveWalker]

Read the Gyro 101 post in the Heli Skills and Setup 101 topic. Gain has nothing to do with the speed of which a gyro sends updates. The gyro senses the rotational rate of the helicopter and compares it with the desired rotational rate from the receiver. The difference is the rotational rate error, and the gain is applied to this error. The Gyro 101 post does a great job of explaining the basics.

Control theory is a very complex topic. I took an entire year's worth of classes in control theory my senior year in college, but that was 15 years ago, so I've forgotten most of what I learned.

[rcjimmy]

I have a GP750 gyro and the servo is a DS420. I am using a 10X radio and the gear switch for the gyro but cannot get the wag out of the tail - is there something you can recommend I try? They tell me I cannot use the gyro setting that is in the 10X radio, I have ot use the gear switch. Do you agree? Is there another setting I can use or do I need to change out the servo to get rid of the wag? Reply to rcjimmy@sbcglobal.net Thank you

[knightofcarnage]

Try another servo. I noticed on the DS420 (at least mine) the movment was quick by jerky not smooth.

[heliaddict22]

can anyone explain why on my mini titan the gyro is so loose when i yaw left? i keep turning the gain up (im at 86% now) with now wag, but yaw to the right is getting sharper, whereas yaw left is still loose. its like im only changing the gain of right yaw or something...can someone help me fix this disasterous problem as it has shown itself as a very bad flight risk

EDIT: its an HG-5000 gyro by Hitec