A few shots to show my paranoid reaction to the rudder hinging design. As designed, it would leave about 3/8" of unsupported Robart hinge to either side of the hinge line, i.e., the mounting points are rather deeply recessed into the skins to make it all look nice and have the rudder's rounded LE fit within the fin's TE skin, but the concern this raises in my mind is that the Robart's will flex and stress a good bit this way. Though not all the closeup pictures of the rudder mods didn't come out well, the last one shows fairly well what I did to make myself feel better abuot it all. Just CA'ed some hard balsa inside to firm things up for the hinge points. This required sawing off the bottom piece of the rudder LE to allow me to slip the balsa pieces up through the rudder LE, but the scar hides well down there with all the tailwheel HW clutter.

A little more detail on the inside to show the LG setup, the pipe mount, a view aft inside the fuselage. Nice, neat work they do here.

What type elevator control linkage are you going to use ?

tommy s

I'm still puzzling through how I will do the elevator connection. Most likely, a CF pushrod, standard stuff. It's interesting though - they provide some nice little FG laminated balsa pieces to build rudder & elevator servo trays from. Now, based on the stock dimensions of the trays, the rudder servo will wind up completely aftwards in the radio bay, right behind the access hatch for the pipe. This leaves only a spot in front of it to lay the elevator servo on it's side. It appears to be a really tight clearance to get the CF rod to go under the rudder servo. I can modify everything and all that, but it just looks a bit tight by factory standard design. I spoke to Carla at Planes Plus today and a photo instruction disk is on the way. To be completely fair, I think the reason I didn't get this with the order is because I had a buddy take this straight back from Toledo and in all the post-show rushing around, the disk got forgotten. Everything is pretty much self explanatory anyway and so much work is already done for you, it's almost criminal .

Thanks for the info, I've got one on order. I was wondering about the control linkage,
if pull-pull or maybe a MK bellcrank would work better. I guess if we could stuff all the
linkage and equipment into our old 60 size airplanes from a few years back this one
should be easy.
Thanks

tommy s

You're thinking about maybe doing pull-pull on the elevator? At a glance, the locations for the phenolic horns appear to be a bit too far outboard to make that an attractive solution, meaning that the cables would probably have to exit the fuselage fairly far ahead of the stab location. I think it should be fairly straightfoward to do typical bearings or pushrod guides in the tailpost.

Instead of using a CF rod, I just put two mini digitals in the stab. Plane balanced with the battery right in front of the wing tube.

hmmm, I could do a pair of 9411SA's. Combined weight is about .8oz more than the mini's I think, but it's what I happen to have. It would sure go together more easily.

Yes, putting two minis in the stab is definitely the easiest way to go. I've never
done that , always worried about them moving exactly alike.

Robert,
How far are you from the first flight ?

tommy s

The plane is ready to fly, I am just waiting for the weather to co-operate!

I installed an MK bellcrank in mine. Seems to work well. I'll post some pictures when I get it all hooked up. Robert I'd sure like to see the completed airplane with the custom paint work!


Greg G.

Ok guys I finally flew it today with a 12 mph cross wind and wow!! the plane took off, without incident and it continued to climb. the plane required one click of right aileron and one click of up elevator. Knife edge using the left rudder pitched a little to the belly so you I willl have to mix some up elevator to mix it out. Right rudder no mixing, not sure why yet. Uplines were great and down lines were as strait as an arrow. I need to put a few more flights on it though, but overall I am very happy. with the plane. I am hoping to fly it again this weekend and I will let you know some more details.

Flew the Otop again today, and the bird still wants to pull to the belly. I added a mix rudder to elevator, but it still pulls to the belly. So the next option is add more mix or and wing adjusters and decrease the incidence of the wings. I will try to easy way first by adding more of the elevator mix, I reaaly do not want to use an y more than 11%. If it still pitches to the belly after using more of a mix, will use the adjusters. Will let you know, how it comes out

Hey Robert are you sure your not tail heavy? Mike

You know Mike I may play around with the CG a little more but when I took the airplane off the first time, I really did not notice that it might hav been tail heavy becuase I did not add any down elevator. I added one click of up. I like the way it flies otherwise, so I have to figure a way out to make it perfrom knife edge. May,be I will try moving the battery forward a bit and see what happens. The only bad thing about this plane is that it does not come with wing adjusters!

Hey Robert,
I'm a little concerned about the airplane being too fast as compared to the widebody stuff. How would you compare the speed range with the Eclipse you flew?

Greg

Gregg the plane does not fly fast at all, it may be a tad faster than the eclipse but it presents very well. I don't think you will have a problem with the speed. I am going to try for the first time this year to experiment with a four bladed prop.

Yeah, it would be nice if it had adjusters. I suppose it wouldn't be too hard to add a set if really needed though. Just curious, have you checked the incidences to see if they are right? BTW, I did have to make a small adjustment to the left stab on mine, as it was almost 2 degrees negative compared to the right stab. Turned out to be really easy to do, just a bit of scraping inside the pin opening and then I just permanently glued the CF pin into that side, with everything set to the correct angle.

You could also do minor changes in a similar way to the wing, though it is tedious. What I've done with the large gas aerobatics planes is to widen the opening on one side and then build it back up with resin and micro balloons on the other, then fine sand it to fit the AR pin.

It would actually be easy to add adjusters to this plane, as the phenloic for the adjusters would fit nice and snug in the carbon fiber wing retainer. not quite sure if I want to go that route yet.

Did you use the stock hinging on the rudder and if so are you happy with
how it works ?

tommy s

Tommy I did use the smaller robarts hinges, at first but they broke, so I went with the next size up.

Went and flew the plane again today, and the conclusion is that it needs wing adjusters. I have about a 10 mix on the elevator and when I add in the rudder to straghten to the plane in cross windy conditions, is does some funky things. I typically do not like to use a mix and I feel that once i add the wing adjuster to this plane, it is going to be one of the better planes that I have flown. The plane does not screw out of tight loops go up and down like and arrow, spped is very constant. I seem to prefer it right now over my Impact, something about this plane just feels right. I experimented with moving the CG forward, I did help a little with Knife edge but not enough for me to not add the wing adjusters. The wind has been crazy here in Nebraska for the last few days, so I have not really gotten to trim the plane like I would like to. As metioned before in my previous post one click of right and now with the CG more forward three clicks of up. NO rudder trim. Again I hope to fly it in some calm conditions to really tell what it's going to behave like. It however does handle the wind really well. I will keep adding more info as I fly it some more.

Got the first two maiden flights on my OTOP today. Only two since it was about 40 deg F, 20 mph winds and I froze myself running a few tanks through the new OS 1.40 in the nose. I will have to get out on a calmer day, but it was possible to tell that it's going to be a very good airplane indeed. Running a tad tail heavy right now, since I caved in and went with dual servos in the stabs (9411's). Even with a 5 cell 2700 mAH NiMH in the nose, it needs more, maybe another 2 oz I reckon. But, this thing has a set of rails it wants to follow through inside and outside radius's. Flew my Focus II today for comparison and the OTOP was steadier, even in it's tailheavy condition. There is pitching to the belly ofcourse and I hope that with the corrected CG, I won't have to go for wing adjusters too.

Nice steady speed, good brakes coming down, can't wait for a better day and a flatter pitched prop (only had a 16x13 handy). Looking good so far...

Any more flying updates out there?

Hi Guys,

I'm flying for a UK distributor this season, one of the planes in their catalogue is the OTOP.

What's the best motor for this model?

Any advice greatly appreciated - I' ve got to get this bird set up quick!

thanks

Julian