I am going to install an OS 120ax at a Revolver 70 ....

Besides , landing gear reinforcement , Robart Pin hinges , and a stronger Firewall what more can I do ?

Will use Blue Bird digital servos , and will use 2 of them (7.2 kg) at elevon , one 10.4 kg at rudder , and another 2 (7.2kg) at ailerons

dont know how to post pics ..


Could someone help me ?

Hi Ice

Sounds like you are pretty much on the mark with your plans. Servos sound more than adequate. Your bird is likely to be pretty nose heavy with that engine, and the servos installed by the book. You might think about dual elevator servos, mounted aft. Search my name this thread, and you will see detailed pics of how to do it (with two different R70 builds).

Good luck with it. If you have specific questions, ask!

Bill

Thanks Bill , I will search about your servo location , but...

I will install 2 LiFe Hyperion Packs over the servo tray ... I think it can help with balance ....

but I have a quastion ..

1/8 or 3/16 Robart Pin Hinges ?


Best regards

Need to get cold ...

1/8" is perfect

ICEMAN - You can always mount a battery aft of the servo tray - I create a small platform back there and and tie-wrap the battery down. Also, you may want to re-epoxy the wing servo trays - they have a tendency to slip out mid-flight on the Rev 70. Good luck with your build.

btw - the way I post pics is to hit "reply" to the last post - then you have an "attachments" option.

Here is some pics...

I was thinking to make an "in cowl muffler" , just not to make an oversized muffler window .... but I gave up ! To much work and could make engine run wrong , without compression or with to much compression , so ...

Today I install Bison Pitts muffler and cowl ...

And install glow plud driver

Where do I need to re-epoxy the wing servo tray ?

ICEMAN - To anchor those wing servo boxes what I (and others) have done is to add a "floor" (actually a ceiling) to to the box and epoxy that floor onto the wing foam and then to the box sidewalls. Just be sure to use thin wood, else you'll use up space needed for the servo. Some pics attached (my epoxy job could have been neater).

The general idea is to make the attachment of the plywood servo box more secure to the wing's structural foam.

Most of us put epoxy into all the interior joints of the servo box, and work some down the outside of the box between the plywood and the foam.

These boxes have come loose on a number of R70s, particularly those that are flown hard. Losing an aileron is not quite as bad as losing an elevator, but can certainly cause a crash.

-
I just missed Mike's post above, which is more informative with pictures.

Consider adding more wood to the tail wheel area where it is glued to the fuse, it is a weak spot also, there are pics of how otheres have done it on this thread

+1 on the recommendation to strengthen the tail wheel mount. Lite ply at a minimum, and a small piece of hardwood, spruce, or basswood may be better. You will probably need to chisel out a recess for the new wood. An alternative seen on this thread is to install blind nuts from the inside backed up to a piece of light ply, and then to use bolt to hold the tail gear in place. That of course requires that you are comfortable cutting and repairing the covering in the tail. The balsa back there is really soft, and if you land on grass, your tail wheel is certain to tear out, even with good landings.

and what Tail wheel are you usually using ? Dubro .40 - .90 ?

Agreed with wjcalhoun. I embed a piece of basswood in my tail section. It's about 3/8 x 3/8 x 3". Requires digging out a hole, and you need to be careful not to dig TOO deep, or you'll go straight through to open space. Need to leave a box of foam to epoxy the basswood too. Once dry you file it down (if needed), cover with trim and screw the third party gear in. Unlike the production rear gear, this mount will never fail. (it does add some weight to the tail, but that seems more than offset by the larger engines most of us are using).

Sullivan, 5-12 lbs I think, have had no problems with it since upgrading

You can get by with just peeling away the covering at the tailwheel mount area and soaking the balsa with thin CA to harden it. I did that and used the Sullivan tailwheel and have not had any problems and I fly from a grass runway. Of course, the better way is to install some basswood or lite ply.

Ice
I have used the sullivan - a good wheel system
My current R70 build has a great planes scale gear; i like the look a bit better, but honestly, the tail gear is about #15 on the list of imporatnt things.

if your going to put our servos in the back of this bird here is  a good video to consider   <h1 style="margin-top: 0px; margin-right: 0px; margin-bottom: 5px; margin-left: 0px; padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; border-top-width: 0px; border-right-width: 0px; border-bottom-width: 0px; border-left-width: 0px; border-style: initial; border-color: initial; border-image: initial; font-size: 1.8333em; background-image: initial; background-attachment: initial; background-origin: initial; background-clip: initial; background-color: rgb(235, 235, 235); height: 1.1363em; max-height: 1.1363em; line-height: 1.1363em; color: rgb(51, 51, 51); overflow-x: hidden; overflow-y: hidden; font-family: arial, sans-serif; text-align: left; " id="watch-headline-title"><span style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; border-top-width: 0px; border-right-width: 0px; border-bottom-width: 0px; border-left-width: 0px; border-style: initial; border-color: initial; border-image: initial; background-image: initial; background-attachment: initial; background-origin: initial; background-clip: initial; background-color: transparent; " title="revolver 70 servo to tail 001.AVI" dir="ltr" id="eow-title">revolver 70 servo to tail 001.AVI</span></h1>

Chandley ... ohh man ....

I´m not to good enough for this job !

Its amazing , but I am a rookie flying , could you imagine me making airplane modifications ?? I´m afraid doing this ...

I think about plling up the pull-pull servo and installing both elevator servos at the same original place ... pull-pull incenter and elevator one in each side...

Your job is beautifull but I am afraid ... I Think balsa job will not be the problem , but realy the monokote , its a big problem to me !

Hey guys, I was wondering if anyone had an extra set of wheel pants. I would like to get a set if possible. Otherwise I will have to get new ones from tower.<div>Thanks</div><div>Ed</div>

hey guys, what throws are you guys using (not real aggressive hard core flying).  The recommended aileron throws seem okay, but i just set up my elevators and the recommended 5/16" low, and 3/4" high seem really shallow. On the low rates it'd seem like this thing would hardly get off the ground on take-off.

I set it to 1/2" low and 1" high, which seems like it would be good but still not too aggressive to get into trouble.

Thanks,
Jeremy

I am using the recommended throws and the plane flies great. Low throws give smooth takeoffs and landings with large loops. High rates give snappy performance. Remember, the tail is airfoil shaped and therefore does not need as great a throw for it to have an effect. I suggest you start with the recommended throws and adjust from there for your flying style.

Bruce

Jeremy
I also found the recommended rates VERY tame. However, as stated above, there IS sufficient throw to control the plane. Unless your airframe is BADLY out of trim, you will have plenty of control with the book rates.

The advice to use recommended until you are comfortable with the plane is good. You, like me, may find that the R70 is more fun to fly with bigger throws.

Microdon , I have just finished the wing servo floor , " piece if cake " ...

But now I have been thinking of that external sider elevon servo !! I want to change that but Im afraid to damage my plane ....

Ice
It is pretty straighforward; several of us have done it. You can search my name for pics of how to add structure aft to support the servos.
Bill

good to know that it flies well with the low elevator throws.

i am doing the recommended set-up with the single servo and the two rods linked together with the collars. The left elevator has a tiny bit more throw when it goes up an inch or more. It probably wont matter unless i get real aggressive with the throws. By the time im flying it with enough throw to be an issue, Ill probably have done a dual aft servo conversion.

I do however wish that this plane was designed from the get go with a pull pull rudder and dual elevator servos....oh well.