Vector 40 Wing Saddle Block

[Peter in Fairfax, VA]

Should the lower wing saddle block, which also holds the main gear, be fastened to the forward fuse just forward of the LG plywood or block?  Vibration and strength-wise, that makes sense.

Not sure what wood is present.  Some ideas are to:

1. Leave it alone.
2. Read the instruction manual and check my other un-assembled Vector NIB.
3. Razor blade off some of the covering and pack in some five minute epoxy when it gets somewhat stiff.
4. Plywood doubler.
5. Screws from the tank compartment back.

thanks,

Peter 

[Peter in Fairfax, VA]

And the outboard wing rides about three inches high, but not inverted.  Requires plenty of attention to tension on the glide to landing.  Plan there is to bend the flap horn, without destroying the flaps.

Having the fun,

Peter

[Brett Buck]

Should the lower wing saddle block, which also holds the main gear, be fastened to the forward fuse just forward of the LG plywood or block?  Vibration and strength-wise, that makes sense.

Not sure what wood is present.

   Of course, what else would you do with it? Clean the rear of F2 (plywood fuse bulkhead) and the front of F2a (front bulkhead of belly pan) completely bare wood on both sides. Fit the belly pan to the wing to the point that it is flush with the rest of the fuselage by adjusting the saddle on the belly pan. When you are satisified with the fit, cut a bit of end-grain balsa to fill the gap at the front so that you can solidly glue F2a to F2 across the full face of F2a. You will certainly have to cut it too thick, then glue it to F2A, then sand it to fit, so the belly pan goes back in place. Note that you want to fit the belly pan perfectly *first*, so that when you go to fit the gapfiller you will know for sure that the only thing that needs an adjustment is the gapfiller. When that fits perfectly, go fix the gap that probably now exists at the rear of the belly pan, so everything fits properly with no gaps. Then glue it all together with lots of glue at the front (because the end-grain wood will suck up a lot of it). I forget how this belly pan goes on, you might have to put the doublers across the rear joint into the fuselage first, because there may not be access to it once you install the belly pan.
 
   Again, I don't recall, it's possible that there is no F2a, in which case, you have to make one, then proceed as suggested. You might be able to dispense with the gap filler if you can install your own F2a, just fit the pan, and if the gap is small (<1/32") you can just install F2a in the right spot to take up the space.

   You *might* be OK just leaving the gap, but then all that holds the engine is the glue joint on the top part of the fuselage. Magnum 32/36, PA40UL *might* get away with that, no way with a Fox/MCoy/Johnson, it will start stress cracking before you even get it started the first time.

    Brett


p,s,, the later messages suggest *you have already flown it this way*. In any case, this just makes it slightly more difficult, square off the gap, clean it as well as you can, then insert a shim to take up the gap with LOTS of epoxy. I might also inset spruce longerons into the bottom and sides.
   

[Tim Just]

I would follow Brett’s advise before your next flight.  One of my ARF E Vector 40’s fuselages folded in flight at that station.   There is very little structure in the fuselage directly above the leading edge. 

Tim

[Peter in Fairfax, VA]

Ultimately, I was able to force plenty of epoxy into the joint.  Bent the flap horn, too.  100% ready for my next visit to the flying field.

Thanks again for the advice,

Peter

[Mark wood]

I would follow Brett’s advise before your next flight.  One of my ARF E Vector 40’s fuselages folded in flight at that station.   There is very little structure in the fuselage directly above the leading edge. 

Tim

Currently working on an E Vector and you just confirmed what I was concerned about. Thank you Tim. I also had troubles with the ball joints colliding on the flap horn. Here's a question. Which holes do they, in fact, go. I put the bellcrank to falp in the top hole and the elevator in the middle one.

[Geoff Goodworth]

Mark, I have that problem with an ARF Oriental when I replaced the MS threaded clevises with a ball joint and 4-40 clevis on a carbon fibre tube rear pushrod.

There was just enough up elevator for the model to fly the pattern but nothing spare.

Having learned from the Oriental, I'm replacing the horn on my Vectors with Tom Morris horns.

As for the lower fuselage, I'm not convinced that the saddle fit is all that flash

Steve Teerlinck (Flying Models article October 2011) made a couple of saddles that held the wing in tight with rubber bands while he fettled the wing fuselage joint.

I plan to do that and use 'biscuits' like those used in furniture making to reinforce the joints on the sides.I suspect that when everything is tight and aligned, there will be space at both the front and back of the lower fuselage saddle that will require filling with thin ply.

I can add that we've had a couple of Vectors at our club break their fuselages at the back of the wing on heavy landings — not significant crashes. Therefore, reinforcement of the joints between the saddle and the fuselage will be beneficial.

Another issue is the stabiliser. The way the rear fuselage is constructed, you can set everything up at 0-0-0 but you could also lift the stabiliser LE to give about 1° of incidence.

Some of those here, much more expert than me, suggest this is a good thing.

[Brett Buck]

Another issue is the stabiliser. The way the rear fuselage is constructed, you can set everything up at 0-0-0 but you could also lift the stabiliser LE to give about 1° of incidence.

Some of those here, much more expert than me, suggest this is a good thing.

    That sounds like a lot too much, to me. I more-or-less started the idea in modern times, but use only 1/4 degree and that means a lot less on my stabilizer than on the Vector. Just make sure it is not past 0-0 on the side of "up" elevator.

   BTW, back the belly pan, you have to make solid wood joints on the front and back, and have a doubler on the rear joint. I also note, even though it may be obvious, that you want to install the belly pan *before* you put on the stabilizer, so that you can line it up. The other way around, there's a good chance that the aft fuselage will get tweaked when you put in the belly pan.

     Brett

[Air Ministry .]

The Olde long straight stick on the stab trick , .

To see its aiming biased up . Scrawling lines , some people use 1/16 to 3/32 across the full Stab./ Elevator chord. Half that ( or less ) on just the stab .
Seems the longer the moment the less. Around past 20 inch , 0-0 may be wiser .

The deal is to EVEN THE TURN RATE , whilst the elevators are in line with the stab . Flaps & controls at Neutral .SAVES dialing in unsightly ? Down Elevator , for and even turn
insides & outside manouvres . 

[Brett Buck]

The Olde long straight stick on the stab trick , .

To see its aiming biased up . Scrawling lines , some people use 1/16 to 3/32 across the full Stab./ Elevator chord. Half that ( or less ) on just the stab .

WAY too much.

   Brett

[Dave Harmon]

Currently working on an E Vector and you just confirmed what I was concerned about. Thank you Tim. I also had troubles with the ball joints colliding on the flap horn. Here's a question. Which holes do they, in fact, go. I put the bellcrank to falp in the top hole and the elevator in the middle one.

I assume you are working on a Brodak ARF E-Vector.
I built the glow version and soon discovered that the control system was crap.
I'm not going to have a Z bend on any of my airplanes especially at the bellcrank so I removed the wire and installed a Du-Bro ball link with a carbon tube to the flap horn.
The flap rod connects to the outside hole of the flap horn.
The middle hole goes to the middle hole of the elevator horn.

Also....in the Brodak ARF the goofy ball links are far too large to fit on the flap horn and on the elevator horn.
I replaced them all with the large Du-Bro ball links...can't remember the part number but not the huge links....the next size larger than the standard size.
To make this all fit onto the flap horn without jamming I had to grind a flat on the O/D of the link standoff for clearance.
The links are mounted on opposite sides of the flap horn.
It is close but very secure with stop nuts.....and it will not jam.

The carbon rod that came with the ARF looked suspect to me as well so I made a new one.
The elevator link is a tight fit inside the fuselage so I had to enlarge the cut out in the side of the fuse to allow the bolt to clear.
This airplane was a bit more tedious to assemble due to it's smaller size but I could see right away that I was going to have to do a fair amount of Jake leg engineering and dry runs to ensure everything was gonna fit and work smoothly.
The entire installation is Cadillac smooth!
I used Du-Bro pinned hinges.

I like to place the flap and elevator coupler on a surface plate and bend the coupler to be exactly flat.
Then, lay down both flaps and a straight edge on the hinge line, insert the coupler into the clip with epoxy and tape it all down to the surface plate.
Now both flaps are level with each other and the coupler is in alignment with the hinge line.
Then take it up and it fits exactly onto the wing without any adjustment later.

I added a trim tab as well to correct for any misalignment that is almost always there due to the outer fixed trailing edge.
On these Brodak ARF's....the mfgr ALWAYS glues on the outer trailing edges waaay off....I wish they would not glue them on at all because on every one of these ARF's I have always had to saw them off and fit them back on in trail.
A real pain....

This Vector flies great....no trim needed yet.

[Dave Harmon]

And the outboard wing rides about three inches high, but not inverted.  Requires plenty of attention to tension on the glide to landing.  Plan there is to bend the flap horn, without destroying the flaps.

Having the fun,

Peter

Peter.....check the trailing edges outboard of the flaps.
See my previous post.

[Geoff Goodworth]

Hi guys

Listen to Brett's comments re stabiliser incidence.

I was running on memory from a discussion that Brett and I had some years ago.

The rear of the fuselage has a bed for the stab that I expect to be 0-0-0.

However, the stab on my ARCs is tapered and, if I remember correctly, you could build in about 2°, maybe more, if you lifted the tapered stab so the top surface was at 0-0-0. That, I accept, is way too much. However, given the way the rear fuselage has been constructed, the flexibility is there if you want to experiment.

As for the lower fuselage saddle — which is where this discussion started — I am certain that, if you align the saddle with the bottom of the fuselage and the wing, there will be fresh air at the front and rear of the saddle and possible on the underside of the wing.

My suggestion is that, since woodworking adhesives that wet the timber soak into the balsa and make it stronger, however you choose to fill the voids, ensure that all the voids are filled with balsa or ply so the joints are tight.

[Peter in Fairfax, VA]

Dave,

> I added a trim tab as well to correct for any misalignment that is almost always there due to the outer fixed trailing edge.

Adding a trim tab sounds like a good idea.  Exactly what is this trim tab like?

thanks,

Peter

[Dave Harmon]

Dave,

> I added a trim tab as well to correct for any misalignment that is almost always there due to the outer fixed trailing edge.

Adding a trim tab sounds like a good idea.  Exactly what is this trim tab like?

thanks,

Peter

Peter.....
I don't have a picture of the Vector trim tab but here is how I did my P-40 ARF tab.
Pretty simple....nothing new here but I've never seen a picture that details how to do it.
I did the same thing on the rudder of the P-40.
It flies very well with a Rojett 51.

On the Vector you can cut off the outer t/e and hinge it in this manner or if both t/e are way out of alignment....cut both of them off, glue the inboard t/e back on in trail, then hinge the outboard t/e for some adjustment if needed.
Of course this is assuming that the flaps and elevator are pretty close in alignment.

[Peter in Fairfax, VA]

Dave,

Thanks for showing that mod.  I have a Cardinal with a similar trim tab.  And whoever mentioned that the ARF Vector TE is often angled in an adverse way matches my experience.  My plane would possibly fly better if I sawed off the TE outboard of the flaps, though I do intend to create a similar trim tab.

Peter

[Peter in Fairfax, VA]

Dave,

As shown, I implemented your suggestion and look forward to testing it.

thanks again,

Peter

[Dave Harmon]

Dave,

As shown, I implemented your suggestion and look forward to testing it.

thanks again,

Peter

Looks good Peter.....that should help out with the flight trim.