I'm not being clear enough. The extra brace I'm going to use is to allow the rear wing tie-down bolt to actually contribute something to the front-back support for the wing. As it is, only the front wing hold-down bolt is bolted into a support that has front-back rigidity. By giving some of that rigidity to the rear cross-brace, the rear wing hold-down bolt can backup the front. As it is, the rear brace has no front-rear strength to transfer into the rear bolt. Until it has that strength, the rear bolt does only half the job it could do so very easily.

As it is, the front bolt will have the opportunity to wear out it's support in the wing. As it becomes loose in the wing, there is no backup to it's front-back wearing. By stiffening the rear support by utilizing the surplus rigidity of the front cabane and it's DIAGONAL brace (the brace that supplies the triangulation we both understand completely), the rear bolt will double the front-back support for the wing. That way, the front bolt actually won't have as open an opportunity to worry it's support from within the wing, and there will probably be no wearing.

Sorry that I've not emphasized that point more strongly.

i get it. by putting in the additional brace, you double up (or rather try to elimininate the need of) the wing as a side of the structure thereby reducing the strain on the wing bolts. makes total sense now!!!

and there's an added bonus: when you take off the wing, the rear cabane will not be rigid and it's movement may wear the lower joint. by doing your mod, you ensure that even with the wing off, the structure stays rigid.

awesome, darock, show us some pics!!!

darock,

Did you use the stock aileron pushrods for your aileron mod? They seem at first glance like they would be kinda short since your control horns have more of a distance between each other.

Colin.

Back to the aileron linkages.

I have found several smaller planes around .40 or so that use the same "abberant" linkages, although most of the slightly larger ones favor Darock's solution...

e.g.





Where you can clearly see that the links look just like the WM ones.

wollins,
Sorry I didn't see your post. Yes, the pushrods that were supplied were too short. I picked up a couple of longer ones at the LHS for something like 75cents each or something like that. The ones that're threaded 2-56 on one end. You find them in bulk in a tube in a display. Almost all my pushrods have the metal solder clevis on one end and screw-on clevis on the other. That setup gives an almost bulletproof connection that fits both ends with no "twists" and a straighter run.

opjose,
Interesting "paint" scheme on that green/white airplane. Ozark hasn't been around since????? Truth is, the lower connection design on that airplane is somewhat closer to being "square" than a lot of them and wouldn't cause too much differential. When the biplane has positive stagger the connection that causes the most differential is the upper one. It's absolutely amazing to me that the plane in the lower picture is almost a standard example of the usual rigging. It would seem that at least one or two of those "designers" would actually look at how that rigging works and ask themselves if that was the way the ailerons are supposed to work. I think there is actually an assembly booklet that has a diagram of the correct way to have your pushrods square to servo arms and surface axis of rotation, and then their bleedin' ailerons are rigged just plain dumb and not even close to their diagrams.

Darock, you will have to post some pics of your setup. PLEASE

Darock:

Re: Ozark

Yeah since the 80's I believe. I flew that airline a few times and did like their service...

Re: Aileron's.

I was studying the GP .40 ultimate manual to see what they say...

The Great Plane's .40 ultimate uses the same setup as the WM Ultimate.

The only minor differences are

- They mount the servo in the same place, but aligned along the fuselage.
- The put the control horns all the way back, but tell the builder to install them the same way as the WM.

Of course I'm going with Darock's solution...

Now does anyone make a stock control horn that solves the problem?

A stock control horn could work, but only if the bottom hole in the horn is very close to the base.

The important thing to remember is that since the connecting rod between staggered wings is at an angle, the right angles needed for proper connections made at the top aileron and at the bottom aileron are going to decide where the connect points should be. And the connect point for the top aileron (on a top wing forward stagger) will have to be above the aileron just like the connection at the lower aileron. It will have to be as far above the top aileron as the connect point for the lower aileron is above the lower aileron.

The reason that I cut the base of the control horns and used only the "horn" part was because of the above. It was far easier to simply saw slots to epoxy those parts into the ailerons than it was to find a really short horn that would work for both the top and bottom ailerons.

If you do find a very short horn, then it can be located on the top of the top aileron and on the top of the bottom aileron. It will need to be overhanging the back of the top aileron of course.

That makes sense and is a good suggestion. Thanks.

If I can change the subject on you...

I'm in the middle of building mine with a .46 engine that I plan to side mount with a Pitts muffler, so that the muffler exhausts hang out the bottom.

I'm wondering what I should do about the fuel tubes.

I was planning on using a filler valve on the fuselage to fuel the plane, but realized that I would not be able to easily disconnect the muffler exhaust tubes from the Pitts muffler to tell when the tank is full.


Do I not worry about this because the muffler faces down, so the fuel spills out anyway when the tank is full?

If I go with Uniflow I'm also wondering where to put the pressure relief vent. Is this worth it on this plane?

BTW: spot on about the differences between the WM and the Nitro planes versions, you were absolutely right.

I quit making uniflow tanks about 3 or 4 airplanes ago. They just weren't needed. I run a two line setup when I have easy access to both lines. I'll fill through the feed line. I pull the line off the carb or remote needle and fill until I see fuel start into the muffler line. The muffler pressure line goes to the very top of the tank as any overflow would. The tanks run excellently well. The uniflows couldn't run any better since there is no room for improvement.

I've been running a similar setup with just one modification in both the Ultimate and the CAP. Both cowls give no easy access to the lines. So.......

I've placed a T in the fuel pickup line between the tank to the carb. The branch line simply goes from the T to a hole in the side of the cowl. The hole is just slightly larger than the silicon fuel line. I make a poor man's fuel dot setup with the size of that hole. My line plug does what every effective plug would do, it slightly bulges the line. I size the hole in the cowl so that bulge will slip fit through it. When I push the excess line back into the hole, the bulge pops through the hole and keeps the excess line inside the hole while the head of the plug keeps the end of the line from going through the hole to be lost in the cowl. Obviously, the head of the plug sits there outside the cowl, but it's not exactly noticable. And it works great. Works just like the expensive fueldot hardware and actually costs nothing. After all, it's just a hole and a plug I'd be using anyway.

To fill, I grab the head of the plug and pull the excess line out to grasp it. Pull the plug out and fill. Stick the plug back in the end of the line and then push the excess back into the hole.

Ok thanks, then I should not have a problem with the cowl fueling valve.

I've recently finished assembly of a Skybolt ARF. It also has the lower ailerons driven by servo with the upper ones attached to the lower. Before cutting up the provided hardware for those connections (to use to make my more accurate rigging) I measured the whole deal and mapped it out on paper so it'd be easier to measure the "differing differential" movements.

I actually made full size cutouts that could be hinged and connected to work exactly like the ARF would work with the provided hardware. And took some pictures of the setup. I'm attaching one picture that shows the Skybolt ARF's "problem".

I'm also including a couple of "drawings" I made of the Ultimate situations. One is the stock arrangement. The other is the design of my rigging setup. I'm attaching two of the drawings that show the Ultimate "problem". The drawings were not as accurately done as the cutouts.

Since both airplanes obviously fly good with their stock rigging, it isn't exactly a big deal. But if you'd like for your Skybolt or 40s Ultimate to have ailerons that work like the larger biplanes (that use a servo for each aileron), then the pictures will show why they don't and how to rig them so they will.

Good illustration.

Would you think that in a case such as this, that it would be OK to place the stock aileron horns facing backward, so that both were on the upper side of the wings... ideally hanging back to provide enough clearance for the control wire?

To minimize how strange this may look, the horns could be cut down to the lowest holes.

I'm working on a small 29" electric all wood Ultimate Biplane where this may be the only way to get enough structural support for anything.

You betcha.

The idea is to place the horns so that whatever hole you choose for the connecting rod in that horn, a line drawn from the hinge line to it would then have to turn exactly 90degrees to follow the connecting rod.

The green lines on the picture represent those imaginary lines from the hinge line to the connect points. The red line would be the connecting rod. The idea is obviously to have the red lines make a right angle with the green line.

The picture below is actually a very good representation of how I have rigged my Skybolt. Since the Skybolt will put an appreciable force on the ailerons, I chose to move the horns inboard to gain support from and purchase on the aileron in a thick area of the aileron. So I wound up cutting a small slot out of the upper aileron to give clearance to the connecting rod.

OK, here's a picture of the Skybolt. Reason I went ahead and posted it was it shows the way I use the horns that're supplied in the ARF's hardware. Reason I wanted to show that was it is a way to actually lighten the overall installation.

I cut off the bottom of the horns and simply slot the aileron itself. Epoxy the horn into the slot and you've got a very strong installation. Since you're not using but half the horn itself, that saves weight, but that's not the big savings. Not using the "other part" of the horn and not using the screws saves the most weight.

On your little airplane, you'd be getting rid of a ton of weight.

With the smaller airplanes, we used to avoid using manufactured horns in the first place. They are just too heavy for the application.

We'd simply use some thin plywood. Use it like I've used the plastic horn remnant shown in the Skybolt photo. It's plenty strong enough and we'd strengthen the hole with epoxy, and it'd last forever too. And it cost nothing.

Cost almost nothing.
Weighs even less.
Easier to do.

Good modelers can make or fix anything.

That picture is EXACTLY what I was contemplating doing with a couple of planes.

The small slot to give it needed clearance... Excellent.

I also see that Hobby Lobby has some Graupner Elevator horns that mount at the very end of the control surface.



The second from the right in the above image.
I may order some to see if they also will work.... though cutting existing horns as you've indicated would be just as effective.

Thanks.

I think that hobby lobby solution is a winner for this application. Of course there are much cheaper options but that one looks like a good bet. Try and let us know how it works. I think hobby lobby has a lot of great gadgets. Too bad many of them don't work that well!

Yes, the Hobby Lobby hardware does look good. The 2nd from the left looks the best. It would place the connecting point closest to where it needs to be to be "perfect". And of course, it's proven that perfection isn't an absolute necessity.

That hardware actually will suit some biplanes better than others. The problem of making the connections right angles is most affected by the stagger of the two wings. Lots of stagger causes the most problems. Very little stagger and there is almost no problem. Very little stagger and the 3rd from the left would work. The other thing that contributes to the problem is the size of the ailerons. Longer chord ailerons permit you to move the connecting point away from the hinge line. The farther you can go, the less problem.

I would suggest that y'all seriously consider using the regular horns and slotting them into the ailerons. It's a very simple, quick, and easy job. And it gives a much stronger structure. The epoxy strengthens the balsa around the horn. The other methods usually wind up crushing to a degree, and if the screws aren't perfectly tight, the base will work loose.

All it takes is an Xacto and epoxy. OK, and I use a small drill. I slice the base off the horn. Using the drill bit in my fingers, I put some holes though the horn where it will be buried in the aileron (the glue through the holes links the aileron's wood through the horn). Use the Xacto again to slot the aileron. Apply some epoxy into the slot and press the horn into it. Wipe the squeeze-out away and it's done. It actually takes me less time to do that than to get the bloody screw holes lined up and the screws through the stupid horn flats. They never line up and the screws never want to thread into the flat.

Nice looking ultimate
Hi Just wondering what size spinner that is? 2.75" ?

Just got the nitroplanes version of this plane so will do the mods suggested.


Also I want to get some decent clevises and connectors etc for this plane and a couple of other .40 size planes I have so do I need 4-40 or 2-56?
I am guessing 2-56?

Thanks

The World Models 46 Ultimate takes a 2.25" spinner. At least, that's what's on mine. The one in the picture looks very much like a WM.

No need for 4-40 size at all. Matter of fact, they'd be unnecessarily heavy. Not a lot heavier, but absolutely not needed. In theory, all the weight added to any surface increases the probability of flutter depending on how far aft from the hingeline and the amount.

Here is a picture of the rigging done on my Skybolt. You can see that only the top part of the provided aileron horns are used. The bottoms of the horns are removed, and just the working part of the horn is epoxied into the slot cut into the aileron. Simple, and almost no weight needed. My pushrods are always made with a solder clevis on one end and a screw clevis on the other. I like clevis connections as they cause no twisting torques and like to have one of them rigid, which solder does. No excess solder of course. Same rigging is done on the Ultimate but the picture is better of the Skybolt. Those rods are so short and the air loads so light there is no problem with flexing.

Awesome thanks Da Rock
I will have a look at doing that on my knock off.

I have a 2.75" spinner coming for one of my other planes so I will see what it looks like on the Bipe.

Otherwise I will get another Aluminium 2.25" one at a later date.

I also noticed that the nitro planes one has two screws securing the top wing mount to the fuselage (bracing).
Should I still make up a cross brace?

I guess better to be safe than sorry.


Also will a OS 70 Surpass four stroke be too much weight for this plane? Or would I be better off running the SK .50 and pitts I have coming?
I have both engines on the way. the 70 I bought for my Harmon Rocket III, but the biplane would sound cool with a 4 stroke.

I am guessing not as the biplane was originally designed for a .30 so most likely way overkill. (I dont even know for sure if the .70 is the same size crankcase etc as a .40 2c)

Sorry for all the questions. I want this bird to fly right.

I think the Nitro model has only front and back cabane frames. WM has a diagonal that goes from the top of the front frame to the bottom of the rear. A diagonal really is needed. The WM setup really stiffens the fore-aft rigidity of the cabanes. Truth is, the WM setup stiffens the fore-aft of the front frame. When I put my backup WM Ultimate (the 1st flew so excellently well, that I ordered a backup within a month) together, I plan to take one of the diagonals and reverse it. No added weight, and both front and back frames get extra fore-aft rigidity. Or maybe run a brace straight back at the top of the frames. whatever.........


For sure, that little sucker doesn't need any more power. I've tried to hover mine and the surfaces aren't 3D capable and it's a rocket of a biplane with the OS46AX. I'd use the lighter of the two engines in the Ultimate. Well, if they're both heavier than a 46AX, that is.

It was designed as a .30 size, and really is fast with the 46AX. Mine did balance without added weight with the 46AX however.

Ok cool. Thanks for the info.
I have a 46AX here in my trainer at the moment. I love that engine. I got it second hand from a guy at the field in my original trainer. The motor had done gallons and gallons of fuel, but still had lots of compression and had had the bearings done not long before I got it.
Tons of power, but as its a bit long in the tooth I might leave it in the trainer for slow sunday flights when I get good enough to fly the Ultimate.
I will weigh the SK .50 and the OS 70 and see which one is lighter. My guess would be the 2 stroke SK .50


I will also do the cross brace mod, aileron horn mod and brace the landing gear block.

Anything else I should consider doing?

While I agree with DaRock on the benefits of the cross bracing, I've both the WM and Nitroplanes versions of these planes ( at least two of each ).

I've had one of my NP Ultimate 40s cartwheel end over end very violently on the airfield w/o any apparent damage... ( other pilots were quite impressed with the plane as a result... )

Then I flew the plane all day... performing many high G stunts...

The next day I discovered that one of the interplane struts had broken off after the cartwheel incident, and I had been flying with ONLY the carbane and the remaining strut holding the wings together. They are stronger than they look!

Bottom line, yes you CAN do as he said, but as I discovered it's not NEEDED with the NP version.. but it never-the-less may be a good idea.

BTW. the NP version has a thicker metal center carbane assembly so this may have something to do with it too.
I also only had one screw per leg holding the carbane to the fuse.