HITEC 645 servos for giant scale airplane???
 

Hi everyone,
I am curious what you people think about useing the Hitec 645MG servos all around on a giant pitts special... 50% 1/2 size pitts that is. any thoughts on this would be great!!

Thanks for any ideas or info!!
Jon:D

RE: HITEC 645 servos for giant scale airplane???
 

TOO SMALL,i use 645's in most of my planes and they are great but way to small for that plane.maybe the 5995 tg would go the job

RE: HITEC 645 servos for giant scale airplane???
 

I think you will be OK if the the high deadband (13us) does not bother you. Be sure to use heavy duty extenders and switches to get the most power to the servos. The Hitec 5645 would be a better choice if you want a tighter deadband. Also look at the FUTABA 3050

RE: HITEC 645 servos for giant scale airplane???
 

this is a troll

RE: HITEC 645 servos for giant scale airplane???
 

what do you mean troll laryboy?

RE: HITEC 645 servos for giant scale airplane???
 

As per " Wikipedia " under Phrases you will find this definition:

http://simple.wikipedia.org/wiki/Internet_slang

1. Troll --- to try to provoke a response (as in fishing)
2. Troll -- often used for a person who deliberately makes trouble.

Jon,

If you use the engine you suggested to me in the 10' Pitts then the 645mg would be on the brink of not being quite enough. Consider that your aircraft is quite large and at sometime or other may require large amounts of servo strength or power (in. oz. or ft. lbs. of torque.)

However, please consider using a/or servo/s in this case 645MG's one on each of the ailerons =(4) 2 as per the rudder and for the elevator another 2. That is eight just for the flight controls. In the earlier days this was called cascading or cascaded servos. (this term is not widely used these days.) Some may call using this many servos Redundant: ( in possible relation as to safety and backup (I don't think it is IMHO.)

Consider this situation.... You have your aircraft in a faster than normal dive...and building up to terminal velocity...If you try to pull up and the air speeding over the control surface of the elevator overpowers the servo torque (servo stall) and keeps the elevator flattened out then the use of two servos would not be redundant if it overpowers the force of the airflow.

Other considerations would be to use four servos in the case of the ailerons... maybe redundancy again.....but consider flutter then. The causes = linkage slop or weak servos...poor design..bad hinges? If I can eliminate all of these than is it redundant ?
I don't think so.

Basicly..I would use the 645mgs as outlined above using heavy duty wire, switches, battery packs, heavy duty control horns and etc, etc..The 645's being the smallest that I would use in your case. I am sure that there are others that will disagree.

There are always some but that's life and their answers deserve consideration, evaluation and either rejection or acception on a one on one basis.

I think that the question you asked was a good one. And deserved to be answered.



So here is another Troll...As I am going to be designing and building a 10' Pitts Also just what would be your suggestions.. I am not a fan of digital servos...mainly because of the high bucks envolved..

As I to would like to know what the members suggestions are also.

Cheers

Doug in Denver

RE: HITEC 645 servos for giant scale airplane???
 

Too bad you don't like digital servos. They are better servos. Have you looked at the Hitec 56xx line? Not too expensive. Also the new Futaba 3050.
Digital servos will give you better control response and better protection against flutter.

RE: HITEC 645 servos for giant scale airplane???
 

Will those futaba servos work with a JR radio, those look like they would work perfectly for my pitts!
Is it ok to mix JR, Futaba, and Hitec servos on the same plane???

RE: HITEC 645 servos for giant scale airplane???
 

Hi, Dirtybridy...

Yes the Digitals have a lot of good points.. including programing and testing.
The Programer is of course an added expense...of $xxx.xx if you want and can afford the luxury of lets say seven digital servos + the programer..

The programer is of course usable (as are the servos) in/on multiple aircraft and eventually you will find that they will last for years.. if taken care of and serviced once in a while.

Personaly I am an old phart and do suffer from tremors once in a while and find that the digital servos actually show the effects quicker in the flight of the aircraft, even with the benefits of expotential (spelling ?). Plus am on a very small Social Sercuity monthly income that does not allow for a lot of High Buck items.

So must do with what I can, when I can. This last couple of years I have Pushed the Budget as far as I can even with the purchase of 6 ea. 645mg's at $ 40 plus tax per each..

Guess I'm pleading Poverity in this case even with the odd jobs that I get once in a while. Otherwise I would own the very best.

Ok, off the soap box. heheh

Cheers

Doug

RE: HITEC 645 servos for giant scale airplane???
 

Good Point Doug, with tremors the digitals react quicker and could put your airplane in the ground quicker than you think. I think i might use 1 or 2 digitals on the rudder or something or elevator and put the 645mg's on the ailerons (spelling?)( i should know how to spell that, hahaha) but my other question still left unanswered is: Can you or can you not mix brands of servos on one airplane. For instance JR, Futaba, and hitec?

RE: HITEC 645 servos for giant scale airplane???
 

yes in a word, I have 3 brands in my GS as do a lot of people.

RE: HITEC 645 servos for giant scale airplane???
 

Thank you andyt. Good to know! Thats what i thought just wasn't sure on it!

PP#1

RE: HITEC 645 servos for giant scale airplane???
 

Thanks Jon,

As Andyt said, you can mix and match. But some do not lend themselves well to that situation. Am not at the present doing so, except in one instance and that is my GP GS Super Chipmunk. In this case I am using the 6 HiTec 645mgs on all flight control and one Futaba 3004 for the throttle. But only after I checked the compatibility at 6+ VDC battery supply and the 127 FM Rec. and the 9 C Tx both of course Futaba's.

Later after a couple of flights I had some dither and jitters on the elevator servo which was of course a HiTec.. found the cause to be in the pull/pull connections at the nylon wire and the tube connector. The tube had worn the nylon sheith on the fish leader wire and was making metal to metal intermitent contact at that point. A drop of CA on each connector stabilized that connection and vola no more jitter/dither.

Static spark electricty and a long wire = makes a fine old time radio transmitter on all ALL frequencies..

Do a search for jitter here on the universe, there has been tons of information written on the subject. Along with mismatched servos or servos that need service.
The newer FM Radios are not as suseptable to interference although it always pays to
investigate.

The RC Universe is the best source of information anywhere, anytime.

Try it--- if you get even one bobble Don't Fly, Till You Know Why--- Then Fix It !!!That's the best advice I can give you on that subject..

Cheers

Doug in Denver

RE: HITEC 645 servos for giant scale airplane???
 

I don't know why you would need that programmer. They come set up the best way out of the box.
I got two Futaba 3151 servos from servocity last year for $40. They aren't as strong as the 645 but they will seem like it as they give you all they have sooner.

RE: HITEC 645 servos for giant scale airplane???
 

Dirtybird do you know anything about how the fma coreless 88 0z # s3501m servos are or anything about them?

RE: HITEC 645 servos for giant scale airplane???
 

Sorry. I have not had one of those

RE: HITEC 645 servos for giant scale airplane???
 

Dirtybird: Is there lots of flying sites near you in Arizona? How warm or cold is it there now. Dec 15..... Thanks Capt,n

RE: HITEC 645 servos for giant scale airplane???
 

I'm also looking at these 645mg's for a 27% plane. I have a few of them on various aircraft and they seem to function adequately. Now I'm debating on these or the Futaba 3305's that I have not had experience with. They are very similar in specs. and price. Anyone have experience with both servos? Which one has the advantage?

RE: HITEC 645 servos for giant scale airplane???
 

There are two flying fields within ten miles. One with asphalt runway and the other has a dirt surface. I prefer the dirt surface as its easier on props. The jet guys don't like it though. You can read about our site in Stu Richmonds column in RCR. Old issuses- he has retired.
It was 67 degrees on Dec 15. It was cloudy, quite rare for here.
The sun is shining today (16) - more like it. I plan to spend the day at the field.