amram

Hello,
Can someone provide me with some practical infrmation As to the Central-Hobbies D.E.P.S ?
Goods things, Bad things etc.
Thank you in advance to all answers.
Amram Leshed
F3A Israel

wildnloose

Ok, I'll give you a bone....then you have to finish yourself.

First, Check out Troy Newmans' install article on Central Hobbies site: http://www.centralhobbies.com/instru.../depsinst.html

Then read his other one: http://www.rcuniverse.com/forum/fb.a...25232&key=deps

Now that's what I call a good start...to see more you will have to search this forum. All your answers are here...

jonlowe

My Feedback: (12)

My take, based on one airplane with DEPS.
Pros:
Once elevators are set up, they stay in synch. Don't have to worry about using two channels and differences in servo end points, slight differences in speed, etc.
If you need to change a servo because of worn pots, etc, you can do it in 5 minutes.
Short servo leads
There are some REALLY fast servos for elevator, such as the JR 8417, faster than those in the smaller servo sizes.
Maintenance free. No bellcranks to wear. Very simple setup.
Essentially friction free.

Cons:
Significant changes in trim day to day, and minor changes flight to flight. Apparently the balsa fuselage grows and shrinks a lot, day to day. This is true with my all built up balsa Aggressor, and others have told me the same thing with other built up airplanes. You need to trim a LOT on the first flight of the day, especially if you use fine trim steps on your transmitter. Don't know if this is true with composite airplanes. In contrast, a dual servo set up does not change trim at all, in my experience, over several different airplanes.
No redundancy on servos for elevator. Had a friend successfully land with one working servo this year with a dual servo setup.

You'd think there would be a weight savings over two servos, but there isn't really, by the time you finish adding everything up for both methods. the single servo is heavier to start out, and you need to side mount it.

While I DESPISE setting up two servo elevators, and I like DEPS because of its simplicity, my next airplane will use dual servos, because of the trim issues with DEPS. Really annoying worrying about trim on every flight, and hoping you get it just right on the trim pass.

Just my opinion.

Jon Lowe

wildnloose

Now that Jon has made it easy for you....let me concur with Jon. I only have experience with 2 deps systems, I have noticed the trim changes (minor, but I'm not that experienced either). But let me add that if you want to take weight out of the tail deps is probably your best option. Personally I take what the plane gives me, if its too difficult to install deps then I don't, likewise for dual elevator servos in the tail.

MHester

My Feedback: (1)

I'm gonna ditto exactly what Jon said, with one slight disagreement: It is a bit lighter. This could be important on al electric plane, but not really enough to make a difference on a glow plane.

On composite fuselages, the trim does change, but not nearly as bad as a wood airframe. It's still there, even though some planes are so dead around the elevator you'd hardly notice, hence why some say it doesn't change...it does, but it just may not be an issue.

On a wood plane, it's enough of an issue that I won't do it again. I love the simplicity and the weight, and for an electric it's a great way to go. But on my planes I think I'll use 2 servos in the stabs because the trim changes are substantial enough to make you crazy on wierd days. In the summer time, just trim on the first flight and you're usually set for the day. But if you move your plane from the sun to the shade and back to the sun, you have to trim again. I wouldn't say it's bad enough to never do it or totally abandon the idea for wood planes, it's just that the trim changes under certain contitions can be a PITA.

I'm still looking for the ultimate light weight elevator system for a wood plane, but it looks like I may have to invent it. LOL

-Mike

AWorrest

My Feedback: (5)

If the DEPS has temperature expansion problems, wouldn't a carbon fiber pushrod have the same problems? As I don't want to go the dual servos in the tail route for a plane with a wooden fuselage that I'm about to start, what would you recommend? A fiberglass or wood pushrod?

Allan

amram

Hello,
The airplane i am talking about is 2M Full-Composite F3A.
The JR DS8417 is too heavy while featuring amount of torque which in my view is not necessary for 1/2 elevator.
Can anyone advise me mini digital servo with nylon gear and 2BB that can do the work. (Futaba, JR, hitech etc)
Thanks allot
Amram Leshed

jonlowe

My Feedback: (12)

I only use 8417's with DEPS. For dual elevator servos, DS3421sa's work well.

Jon

Aresti-RCU

My Feedback: (1)

Futaba 9650 also works well. I have a dual 9650 configuration in my Genesis

Scott Smith

My Feedback: (4)

I'm going to give the Sullivan Precision Rods a try. With the bend shown in the picture, they are still silky smooth...you could never do that with the .007 cf rods! Packaging claims less trim change due to temperature.
They do seem heavy though at 28 grams each (full length.)

rcstavros

Looking at the CF pushrod routing in Scott Smith's arrangement I wonder if the curve is acceptable (for .007 rods) or it must be a straight shot from elevator horn to the junction of the two CF rods. Of course curving the rods (and the tubes) makes it easier to set them perpendicular to servo horn. Otherwise there is always an angle between servo travel and carbon/tube line. How much is acceptable ?

jim woodward

Echo Jon's and Mike's statements. Huge trim changes in a built up plane. The way the carbon rods work you need to really get the exit angle to match nearly perfectly with the exact location off the surface control horn. If not, you WILL get friction in the rods. I've done this on 4 planes now and will go strictly with dual elevator servos in the future, and plan to convert my current setups to dual Futaba 9650's. If you use the included Teflon guides and wrap thread around the system to secure it, and you wrap maybe 2 sprials of thread a bit too tight, you get friction. If you don't get the exit angle exactly correct, you get friction. If you disgard the teflon guides and slide carbon rods into carbon tubes, you get a near zero-friction setup, but it will rattle with the engine shaking. It is about a 100% perfect swap in weight between a dual elevator setup and a DEPS setup (I measured everything this summer while getting ready to make weight flying electric for the nats). It is really a question of weight distribution. In retrospect, it just doesn't make sense to use two 40" or so pushrods if you don't really need to, given the better mini-digital servos available today and with thier use and associated 3-6" pushrod. If you are super-weight critical, use the smaller gauge wire on the extensions and you can save 50% of the extension weight with just that change
Thanks,
Jim W.

apereira

I had the Sullivan for years in my Goldberg Sukhoi, I did not had any trim changes, I used to love that, it was always perfect.

Have anyone stripped the gears on the 3421SA on the first pull during installation, it happened to me an the same on a friend's Impact, no binding at all off course.

Regards

grotto2

My Feedback: (2)

If you're flying a two-stroke and need to bring your weight distribution forward, it's hard to beat pull-pull. After going through DEPS on one plane I'm going back to P-P. Absolutely no trim change from flight to flight, month to month. If you want redundancy, you can put a servo on each cable set.

As to difficulty in setup, I'd say pull-pull and DEPS are about equal. Pull-pull requires an openness that doesn't exist in some wooden planes (like maybe an ARF) because of formers and whatnot.

rcu-eur

Hi

Using dual servos on elevator , is there a better ( light) option than the small futaba digitals 9650s , used these before and there is noticable slop on them , even from new, thanks

Scott Smith

My Feedback: (4)

No, you could never get away with that much bend when using the .007 rods...in fact it must be dead straight or it will bind. The Sullivan rods however are very smooth as shown. Regarding trim changes, quoting from the packaging: "Precision Rods are matched to airframe materials to eliminate trim changes from thermal expansion" We'll see!

How about the 3421SA's? I used them sucessfully in a Brio.

BillB

I used DEPS in my last pattern plane and am not going to use it again. The last three that I built (2 Temptations and an Impact) used the MK dual elevator bell crank from Central Hobbies. In the time it took me to get the DEPs system working correctly I could have installed three or four bellcrank systems. The DEPS system changes trim almost every day. With the bellcrank system it was trim it and forget it.

Bill

flyncajun

I have to say that with a little effort the deps system is the best system out there right now
I have used it on my last three airplanes and have no trim change issues with this system
it is not quite as light as the pull pull but it is superior in the wind and lighter than anything else out there
I believe if you take the time to set it up properly it is superior to any thing out there
when I saw Troys first set up I knew it was better than any thing I had used ,,including dual elevator servo`s
which I had continual problems keeping the centers constant
but if you take the time to set any of the above mentioned set ups they all work ok
I just think the deps system is the best overall

TeamVertical

My Feedback: (9)

I just finished installing my second DEPS system and must say it is much quicker the second time. I think it is the most maintance free system out there.

On the ones I have done I routed out the 1/4inch wood to house the teflon tube. This way you will not crush/crimp the teflon tube when you wrap it with thread and cause binding.

Dave

rcstavros

Is it posiible to have a photo of the installed DEPS (servo end) ? I am especially interested to see the angle between the pushrods before their junction. I assume that the 1/4 wood support is straight.
Thank you.

Stavros

Scott Smith

My Feedback: (4)

Not installed, but here's what's left of a salvaged DEPS. The .007 rods are attached using thread and CA. Put about a fifty wraps on the center rod first right at the end, then attach the .007 rods. This will get the .007 rods heading in the right direction (slight V) rather than straight back.

rcstavros

Thank you for the answer Scott. I suppose that the binding produced between the V and the tubes when the servo is moving, is insignificant.
Happy new year.

Scott Smith

My Feedback: (4)

Here's the servo end with the Sullivan push rods...

rcguy!

My Feedback: (69)

.070" diameter, NOT .007" diameter?
Dave