Felix21685

My Feedback: (1)

hey guys


I have my easy sport set up 98% ready to fly..
One thing that i have a problem with is that my throttle pushrod doesnt quite do the job..it doesnt quite cut engine with my trim down and throttle down..yet to reach full performance...full throttle i need to move the trim up also..so i need to move both directions.


now..on the carburator on the engine..you know how there is 2 places to put the clevis onto in the little metal arm thing..on the engine itself.
now it is in the outer hole...the pushrod is binding a little bit...will it do the trick if i bend the pushrod up a little..and straighten it out of course..and move the clevis into the hole that is closest to the carb..will it do what i want it to.
i wanted to ask before i bend the pushrod.. by the way its a TT BB 46 PRO


here is a picture of the engine..(i am talking about the thing with 2 holes in it above the crankcase) i dont know how else to describe it.



the picture doesnt like to work so click
[link=http://www2.towerhobbies.com/cgi-bin/wti0001p?&I=LXKF97&P=7]here![/link]

ok now about my radio..I have a Futaba 4VF...the one that is black.not the new one. the one with the pain in the butt trainer button instead of switch.
i wanted to know how to adjust the tension on the sticks..and the amount of servo travel.

Thanks for all the help
Felix

Razor-RCU

My Feedback: (50)

Moving the arm to the upper position on the carb. arm will help- Use the farthest hole on the servo end and closest to the carb for max. movement-

I am not familiar with your TX, but I would guess that it does not have an endpoint adjustment for the servos- you may have to do it as mentioned above (Mechanically)

Good luck!

FHHuber

Stick tension (I assume you mean the spring action that returns them to center) is adjusted by removing the back of the transmitter case. There is a screw RIGHT beside a sprin. You turn that screw to increase or decrease the spring tension. More tension... and the stick springs to center with more force. Turn as if tightening a screw to add tension.

I don't think the 4V has adjustable travel on the transmitter. you need to do the adjusting mechanically. This is a bit of a pain as you have noted... there's NEVER a set of holes that gives the exact correct throttle travel.[]

This is where "servo savers" come in. You put a spring load device on the servo arm to allow the servo to travel further after it has pulled the carb all the way closed. This is the position you will only use when shutting off the engine, and you won't be leaving the radio system turned on long in this condition.

You don't want to have to deal with the "overtravel" at full throttle, as it is all too likely for you to leave the throttle at full for extended durration while flying. The servo working against the spring load would be drawing a LOT of battery power. So you move the pushrod to the desired holes and adjust for EXACT ful throttle throw and make up for over-travel of the servo at the low end.

My favorite servo saver is 2 ball poit pen springs, 2 wheel collar and an "EZ-Coinnector" with the set screw deleted. The EZ connector is between the pen springs, which are between the wheel collars. (Its cheap and easy to set up) You adjust the travel limits by moving ONE wheel collar to increase tension or both wheel collars to maintainthe same tension. Never set it with free movement whithout compressing a spring. (never compress the springs more than 50%)

forestroke

The other option, which is not as good as FHHubers is to use that disk that comes with your radio that doesn't have any holes drilled in it and drill the hole that gives you exactly the right amount of travel so that you just get a little buzzing when the throttle is closed. It's not as easy as the servo savers, it's not as precise as well... but it works and cost nothin'

MinnFlyer

My Feedback: (4)

Here's a third option...

Due to the fact that the servo's output is rotary (as opposed to linear), by removing the servo arm and reinstalling it at a different angle will make slight variations in throw. Note the different starting positions of servos A1 and B1. Once both servos have rotated the same amount, servo "A" has moved a pushrod further than Servo "B".

Felix21685

My Feedback: (1)

hey thanks guys for all the help i will try again and see if i can get it closer..i dont trust myself with the spring option..
any more ideas...keep em comin
thanks alot...u guys help out a bunch

maiden flight of the easy sport is set next weekend.not this

Felix

Griffin_NC

My Feedback: (3)

I ran into the same problem hooking up this engine lastweek. There was a thread on the board here about throttle servos. The general consensus that I found was to use the inside hole on the engine throttle arm and then start with the inner most hole on the servo and work your way out. That seemed to work wonders for me. I struggled for a few hours getting it working prior to finding this thread. The next night I got it setup in about 20 minutes with this method.

Montague

You can also get adjustable servo arms, many servos come with them. They make this kind of thing a lot easier.

I tend to use the technique Minn described, offsetting the arm to reduce travel after getting it close.

Btw, I also try to set my engines so that:

full throttle+full up trim is wide open
Full down stick+full up trim is a high idle
full down trim + full down stick fully closes the carb and shuts down the engine.