JohnVH

My Feedback: (38)

on my topcat, the elevator, mounted similar to a bobcat, is one servo one elevator, now, the bobcat is split, I am torn between using one servo for it, which if the one servo goes bad, in goes the plane, or I cut it in two, and put another servo on it, and there is a chance I can save it.

SO, is it worth doing? is there a chance of saving it on one half?

Like to hear your opinions please as this is my next step on this thing!!

Thanks much!!

Bobman

My Feedback: (5)

John,

Personal experience speaking here... I ALWAYS use 2 servo's if possible. Saved a plane a few years back when a servo stripped in a big Ultimate bipe. Left elevator jammed at 30deg down elevator. The landing wasn't pretty, but it only cost me a broken prop! Just my 2 cents worth.

Bob

ps.. how do you like the Topcat? I'm considering it for my turbine trainer.

JohnVH

My Feedback: (38)

judging by the poll early I think I can see where its going, Itll be overkill like crazy, but Ive got 8411's for everything but rudders, but there still digitals.

The topcat is a quick building plane, I am not! You can check out my website for pics on progress and some comments on it, I am pretty much done with the major building.

I did have a couple gripes on it, but there minor and are easily fixed. But still shouldnt be that way. Ive been told there revamping the kit and doing a little upgrading so itll be even better!! Overall I am happy with it, there supposed to fly awesome, and there a whole lot more inexpensive than some other options I was looking at!! And TGA has great combo deals!!!!

Woketman

My Feedback: (6)

I did not take the poll cause option two needs to be modified to "stick with one and make it the best damn servo that you can afford and hope it won't fail". If option #2 was that, I'd say its a toss up between #1 & #2. If weight is not a big deal, use two servos and sleep well.

KXH121

My Feedback: (20)

I used one servo for the elevator on the Topcat I built (8411). I have learned form experience that if you change the manufactorers design you are asking for trouble. The Topcat was designed for one servo and the Bobcat was designed for two. I am not an aero engineer so I dont know what the effect would be to modify a proven design. When I first bought my Topcat, I asked Steve about splitting the elevators. Call and ask him his opinion. Good luck, the Topcat is a great jet!

JohnVH

My Feedback: (38)

well, I have four 8411's here, if I split it there will be two on the elevator, if I dont, there will be one there, and one on steering I guess

I have seen at least one topcat with a split elevator already, and one other person that said they were going to do it to there's too.

Thanks

RC_MAN

My Feedback: (11)

Two servos means twice the chance of things going wrong. Get the best servo. Also with one servo there will not be an assymetrical problem due to different centering and holding torques. Ask the pattern guys. Been there done that.

JohnVH

My Feedback: (38)

I was going to use two 8411's with a match box. at least thats the plan

Vincent

My Feedback: (61)

John,

You sound like your mind was made up on this before the poll but my vote is one 8411 with a solid linkage set up. From my experience (in the hundreds of turbo flights) something OTHER than the single servo failure will get your Topcat some day, you can take that to the turbine bank.

Vin...

Laura H

I would say with 2 elevators you have more chance of getting away with out a crash than with 1.....People are posting about problems they are having with their JR servos, so I would say 2 are better than 1. But thats my opinion

Woketman

My Feedback: (6)

What problems are cropping up with the JR servos?

Laura H

Woketman,
See bobcat servos post!

JohnVH

My Feedback: (38)

actually my mind was leaning towards one servo at the start, but yesterday majority was two servo's, I still have not cut them into two yet, BUT, this is how the bobcat comes, with two, BVM does there homework too right?

Chris Huhn

The BVM protoype Phantom was eventually lost to a failed elevator servo (single servo setup). Sure, it was the best servo at the time, but it took a huge load as well.

I don't know the answer to your question. Lighter weight airplane with lower loads on the servo should make it last a long time and odds are something else will get it over time.

However, a backup will likely save the airplane in the unlikely event of an elevator servo failure. Do you buy insurance or not?

Regards,
Chris

exaustgas

My Feedback: (1)

are they ailerons split? because remember if you loose one of those the jet will pack in also. I recomend either nice servos on a split elevator, or one great servo on the elevator. The aileron reason is why I like the new kangaroo. I can loose a servo in a wing and still have elevator and aileron control. If the topcat has single strip ailerons, make sure you have GREAT servos on those babies.


Justmy thoughts,
Ted

JohnVH

My Feedback: (38)

Like I mentioned already, everything is getting 8411's, unless there not the best, alot use them. I feel I can fly with one aileron, I have done it on a prop plane already, not by choice, but you never know. if its hard over it may be difficult, but likely possible with rudders?

Doug Cronkhite

My Feedback: (34)

There have been 2 people reporting problems with the 3421. That's two out of the thousands of 3421's in use. Let's not blow this out of proportion guys.

Doug Cronkhite
Team JR

DavidR

My Feedback: (1)

Read the Bobcat Servos post. And you will see our line of thinking on the 3421 servos. I have around 30 of the 8411's and have never had problems out of them. Also note that I am not ripping the 3421's out of my airplane just watching them closely right now in lieu of a problem we have had with them in one airplane. The tech people at Horizon have told us they have NOT been having widespread problems with them.

As far as the elevator in your Topcat goes what does the manufacturer recommend???? I would follow his design as he should know best what is best for his airframe. It has been tested with one elevator and seems to fly fine in that configuration why re engineer it.

David Reid

JohnVH

My Feedback: (38)

The manual says one, I want to do what I can to make sure Ill have a chance to save it if that ONE servo goes bad is all, looking for opinions from all you guys, so far, It leaning towards getting split, I cant see any problems with two, others have done it and it worked great, and BVM did it on there's for a reason Im sure.

Thanks

Gordon Mc

My Feedback: (11)

I absolutely agree, even though I'm one of the aforementioned two people who have had some problems !

When I posted the info about the failures that I had, I did that NOT to scare anyone away from the servos, or to bash JR's reputation in any way (coz I happen to think they're the best ! ;-), but to share info with someone else who had a similar problem, to see if there was possibly a common cause. So - let's see if we can keep it in that vein rather than making a mountain out of a molehill. (Remember that you are more likely to read that two people died in a housefire while they slept last night than that 300 million others didn't ! Perspective is important.)

A couple of the team JR guys have stepped up to the plate by asking the Horizon service guys to take a good close look at the servos that I'm returning. I couldn't ask for more than that.

In the meantime ... I'm heading out in a couple of hours to put a few more flights on my all-JR equiped Bobcat.

Thanx,
Gordon

mongo

My Feedback: (15)

try 2 servos coupled together to drive one linkage, then if one fails ya still have control, even if at reduced throw.

JohnVH

My Feedback: (38)

one drive linkage? got a pic of that?

RcBBQ

My Feedback: (1)

It used to not matter to me but after almost having my plane destroyed, I say TWO.
Here's the story: I was out flying with a friend and we were practicing some synchronized flying. Well, our timing fell off a bit and BAM, he took off my entire left horizontal stab and elevator.
Lucky for me it was on the opposite side of the linkage so I was able to come on down. If it were a single elevator, I could have kissed my plane goodbye.

Spit_1

In the past months we build a jet called Vienna-JET an he looks like the bobcat but we designed the jet completely new.

At beginning of the project the question was one or two servos on stab and a splitted elevator or in one piece.

After discussion we build a splitted elevator with two JR5077 servos. We have with this configuration no problems in flight and if the cause of a failure of one elevator we have the second for landing.
We canīt see any problems in loops an levelflight.

Greetings from Austria!

Yale

My Feedback: (1)

l flew maiden flight Sunday Topcat ,on the seconded flight rocket control horn screw came out ,gone landed with out elevator control,a little hot and sort of hard ,,maybe two would of been better servos that is,lf l would had longer runway would been no problem 300 feet and hot