I can understand the thinking, I just haven't read anything about it on any of the Hitec sites and really would like to see what they have to say about it. I know that the Sukhoi at idle and on the ground really shook the tail feathers and it had crossed my mind more then once, never had a problem though. I may have just gotten lucky?? If you look you can see how close I had both the elevator servos mounted to the elevator halfs and I used short 4-40 control rods. The Extra doesn't vibrate much at all?? Surprised me!! The 6985s work outstanding on it too. I found a close out once on the 6985s at Servo City and bought up a big pile of them, very good servos!! Talk about a deal!!!

I am a proud new owner of an O.S. FT-120 flat twin four stroke. 9.95cc x 2 .  Got it for a steal. Now for the stripping, cleaning, then rebuilding. Fun stuff if you ask me.

Lucky!! I have never had one myself but would like to try one out some day. That would be my engine of choice in a nice Cub.

HAHA funny you should mention...I took it out a 105" wingspan cub. Gunna get a gasser for that one though. Probably a DLE-30. I was told that would be the perfect engine for that size cub.

A Cub can fly with just a stiff wind, they need almost no power, a nice rubber band would do it. I have flown giant Cubs with the G-23, today it's the G-26 but same thing. The 30cc would be great in it. Just for fun go look at the CRRC engines, I fly with a few guys using them with good results. I think they go from the 26 right to the 40 but if I had the choice between a 30 and 40 I would go with a 40 every time. I has more uses down the road in different planes. The yellow Sukhoi I posted uses the Brison 2.4 40cc gas engine, it's an 80 incher but very light for it's size, I built it from plans I bought in MAN and did the mods for the gasser, it was designed for the 1.20 FS glow. Most anything with an 80 inch wing I go right to about 40cc gassers. I have the Brisons and they are more high performance then the new gassers from China.

Oh, those are nice, and the prices aren't bad either. I don't think 30 would be a bad size at all. I found a site that sells DLE-30's with electric start for $240. My dad has had a 105" Piper Cub kit for about 6 years, and I finally got him to want to build it.  Who knows...A couple rubber bands would save lots of time and money

I thought this was common knowlege, there were some rather long threads on this subject in the radio section and also in the Hitec support thread. You can run what you want too, but why take the chance. I do know for a fact that Hitec does not recommend using Karbonite geared servos in gas engines if you don't believe me do a search in the radio section and the Hitec support section.

Don’t buy garbage servos. You will undoubtedly progress to advance airplanes and need good servos (btw as others have stated the extra is an advance flying aircraft.) If you are new to this you should be looking at a midstar or 4 star to learn on. With a simulator like the Real Flight it is very possible to go from a midstar to an extra in 3 or 4 months. (This really depends on how much you are willing to fly…) We have members in our club who have done it. In fact it is actually a smart way to go. Skip the bad habit planes like the sse and twist, jump to a good stable plane that flies like an arrow.

With servos you want to pay attention to strength (torque) speed, gearing (metal, karbon nylon) With a 60 size plane 60-80 in oz of torque is good. Speed around .15 to .17 is good. Faster servos make the plane more responsive. 15-17 is not fast. If you want to see fast check out a .08 servo. The general need for a fast servo is on 3d aircraft where the surfaces are moving very quickly. The Goldberg Extra doesn’t need speed and you won’t be 3ding for at least 4 years.


With hitec there are digital and analog. If you are certain you will be flying large scale gas then digitals are the way to go. The 5625 ($50ish) is a generally good fast strong servo that can be used on planes up to 27% with 6v. 35% aircraft need more omf like a 7955 ($100ish). You should buy your servos with the next plane or 2 in mind. Some people look at this as overkill I see it as an investment… With my 2, 27% aircraft I use 5985 ($80ish each) all around. My current Goldberg 60 size Ultimate I have 985 on the ailerons and rudder and 625 on the elevator, I will be switching out the 625 for 985 when I can afford it. I like the precision of them. I also like a good strong rudder…

If you get digitals get some decent batteries as they suck the power! Make sure your battery can handle a constant 1 amp draw. This is a good idea with either analog or digital…

With analog, the boiled down choices, 625 faster-weaker, 645 slower-stronger (cheaper cored motors) & 965 faster-weaker, 985 slower-stronger (more expensive coreless motors.) They are all ball bearing and are metal geared. They work great in a direct pull-pull. If you are not experienced you won’t notice the difference between a 625 and a 985. For the Goldberg extra the 625 would be great on all surfaces on 4.8v plus they are about $30 each, the 985, 965 are about $70 each but are very smooth very precise. If you were to be doing precision pattern or imac flying then the coreless is the way to go but for general hucking on a 60 size plane the 625 is a good cheap choice.

Hope this helps.

So is the HS-6635HB's a "garbage" servo? That's what I was planning to get from what others have said.

This could sort of lead to a which is better Chevy or Ford. IMHO the 6635's are great servos but for the Extra and planes to come i would suggest you consider the 5485's, they are a great new standard digital, 72 ouces of torque and considerably less money. For whatever it may be worth, i have some in my new CG Extra.

This is what I did, I did a search on karbonite geared servos and came up with guys making statements, Mono vs Ultra type of stuff, normal RCU chit chat. I went ahead and emailed hitec direct and posted the question to them. I have been using them in 40% IMAC and giant scale IMAA planes for a very long time and running some very big gas engines. Perhaps I have just gotten lucky?? Maybe I just set up my planes so well I never have problems?? I will post up the answer from HT when I get one. I only use Ultra!! Mono is OK for trim!

LOL ,yea it could but it is not my intention. Garbage is probably a harsh term. For that I apologize. I am meaning entry level ie 325, 425, 475 that quickly become one of those things that collect dust. (And as my other half puts it, if it collects dust garbage it...lol) They are good for 40 size and circuit flying 60 size. Once the flier has progressed past this they become unused. People will say to use them on the throttle but I found that after a year or 2 I was looking for a very fast servo for the throttle for more response. Definitely buy in your price range but try to keep the next plane in mind when buying to avoid wasting money. As you progress the aircraft becomes more expensive. It also depends on how long you want to fly a particular plane. It took me about 7 planes before I found my nitch (extras and ultimates, mainly extras, no other plane does a lomkavek as beautiful as a scale extra 300 and no other plane flat spins better than an ultimate)

I don’t know about the 6635. I tried a 635 once for a pull-pull and found that even tho it was ball bearing and good torque and speed the tension put on it by the pull-pull caused the centering to become terrible. 635 is not an entry level servo either... One of those servos that I completely dislike and sits in its box un-used… I wasted $30 on it… Good thing I only bought one!

To each his own. Some people will like some servos other people will hate those same servos.

Keep in mind that servos do wear out. Their motors die, circuit boards fail so don’t buy with too many planes in mind. I usually buy with the next size of aircraft in mind. With a 40 size I get something that can stand up in a 60 size and with a 60 size I get something that can standup in a 120 size etc… That way I can replace the gear set and get another season out of them and I can trust that they are less likely to fail from stress. You will reach an impasse tho. When you become a more aggressive flier servos will wear out faster. I am usually pretty hard on mine. Full power blenders and fully power crazy water falls. My buddy (who is the video below) is counting how many more blenders I have with my reactor before he thinks my servos will fail. (and probably will) Seriously the blender spins so fast and so hard the whole maneuver including the flat spin is a blur.

I have a friend who flies 44% imac/pattern and he changes his servos out completely every season. Talk about expensive at $200 a servo across 13 high voltage jr servos. But when your plane is worth $15,000 it is minor compared to a complete loss.

Here is a video if any one wants to see him fly. The vidographer cut out all of the rolling loops unfortunately. The rolling loops are text book great, even the bottom of them. Too bad they were cut out. Including a rolling loop that consisted of 1 roll for the whole loop. I have personally watched him do harrier rolls 20 feet off the deck with this plane and 10 feet off the deck with his 35%. Lol, I could feel the wind from the spinning wing tips on my face! The plane below is a one of a kind Extra 330, very few were made. Hand crafted no less!! All composite.

[youtube]http://www.youtube.com/watch?v=RYwe6IC5nrI[/youtube]

More pics and stuff are at our website http://www3.telus.net/rrcc

For cheaper servos and 60 size planes I usually use 625, 645, 5625. I consider these cheap. Keep in mind that I am hard on my planes hence the reason for the stronger servo. With my recent 60 size ultimate and having tried 985, the 985 is my personal choice but it is expensive.

Here's some pictures of my plane so far, I pretty much only have to Ultrakote it. I don't think it looks to bad..

Looks great! But I'd wig out if that was my pool table...hope there's no oil dripping from that exhaust

It's a brand new AX 120, never been run, so it's fine. I always put a cover over it, but I must have been playing just before the picture.</p>