Mustang Fever

My Feedback: (2)

Mine showed the fin as solid 1/4, as well, but I was out of it so I used the built up method. I've had enough solid surfaces warp on me that I've about given up on them. Seems to work ok for rudders and elevators, but even large, solid stock ailerons and flaps can be problem.

Redwulf__34

Bob,
How did you put your wing together? I have seen a couple of different methods suggested but I can see potential issues with them all. The original Jensen said to "block" up the trailing edge and glue the ribs into the lower spar and trailing edge at the same time. The other method I have seen suggested (not from Jensen) is to glue the ribs into the trailing edge laying flat, then glue in the top spar, flip it over and glue in the lower spar.

It seems to met he best method would be Jensen's, blocking up the trailing edge and glue them into the lower spar and trailing edge at the same time. It would be easier to make sure the blocking is straight.

Thoughts?
Sean

Mustang Fever

My Feedback: (2)

Sean:

That blocking up of the trailing edge takes place only at the very tip- the top and bottom trailing edge sheeting "taper" to match the wing tip piece. Everything else is flat on the table up to and including the last rib. I would wait until the tip piece is glued on before bending the top and bottom sheeting to match. (Actually, I didn't do it that way. I ended the trailing edge sheeting at the last rib and just used a thicker tip piece. )

Redwulf__34

I'm not sure I'm totally following you Bob. I'll check closer tonite to see but I was pretty sure they show blocking up the entire trailing edge. If I understand you correctly are you saying the rib should fit over the lower spar and sit down on the trailing edge sheeting as is? The angle of the cut out for my lower spar is such that it brings the trailing edge up off the table. I may have to scan or take some pics to explain it correctly..

Sean

Redwulf__34

I didn't look close enough. Your were right it was blocking up the tip. I think I find an alteranative method there as well. Hopefully time will allow me to start putting the wing together tonite. Did you use spruce for the secondary (frontal) spar too?

Sean

Mustang Fever

My Feedback: (2)

Sean:

For a while there I was beginning to wonder if the Jensen plans were different. Sounds like they are the same.

I used balsa for the front spar. (3/16 sq?) Can't remember.

8178

My Feedback: (17)

I’ve built a bunch of Jensen kits and I think there maybe some confusion here. The wing rib is flat from the back edge of the rib notch all the way to the trailing edge cut out. Each wing panel is built by laying the ribs down on the flat area. The block shown on the plans is used to twist the trailing edge at the last rib so it will line up with the wing tip piece. You can do that part after the wing is completely built. Again I highly recommend you build in a small amount of dihedral to avoid the goofy drooped wing look.

Mustang Fever

My Feedback: (2)

That's what we said, only different. The section "C-C" on the wing plan shows it pretty clearly.

My wing's flat and it don't look droopy, and it flies so much better than it did with the first, dihedraled wing.

Redwulf__34

Thanks 8178, I do see it exactly the same as you described. I looked at it too quickly and didnt see it all.
Gonna start putting her together tonite. Bob, I was planning on balsa on the secondary frontal spars. I thought I better make sure.

Sean

Redwulf__34

Wow, lots of work today! The spar notches on my rib jig were not right. I thought about correcting it but figured I would just hand notch them. That was a mistake! It took way too long. But they are right. Got it all layed up and she is nice and straight. I have to trim down the center ribs 1/16 for the sheeting yet then I can glue it all up.

I don't know why my spar notches were off on the jig. I had actually spot glued the two sides together when I made them. For some reason when I stacked all the ribs between them and bolted them together they were not lined up square across from each other. They were just a tad undersized and I could have set up my router table with a 1/4 bit and fixed it right up with the ribs in place. But my router table was buried under a ton of balsa. On hind site it would have been easier to dig it out!

I'll get some pictures up when I get the wing all glued up.

Sean

Redwulf__34

Hey guys,
I got the wing all glued up now. Last night I got the top spar, and frontal secondary spars in. I'll get the leading edge in tonite. I have a few pics here before I glued in the upper spars.


I made a slight change to the trailing edge. I got some trailing edge stock and I'm using it for a solid trailing edge. I descreased the thickness of the trailing edge sheeting to 1/16" while doing this. One question, my trailing edge stock isnt' going to be "deep" enough for the wing bolt location. I am assuming filling the section with solid balsa is good? It doesnt need to be hardwood in between the sheeting, does it?

Sean

Mustang Fever

My Feedback: (2)

Sean:

Lookin real nice. Good call on the TE. You won't regret it. I found I was able to get the LE stub ribs in after all the spars and the LE piece were in place. Don't forget em. I nearly did, had some covering ironed down before I realized it.

Block balsa "between the sheets" will be fine for wing bolts. Just glue it in before the top TE sheet goes on, a little higher than what you need, and sand it flush with the tops of the center section ribs. One thing I do with wing bolts is to counterbore down into the block a with a 5/8 Forstner bit, then glue in a 1/16 or 1/8 ply reinforcing washer so the bolt doesn't crush the balsa every time it's tightened.

Redwulf__34

Thanks Bob,
I'm thinking of gluing in those LE stub ribs before the LE. I figured it could be done later but it would probably take a little extra work.

How much do you guys use CA type glue and how much do you use regular wood glue? I'm finding most of my fits are pretty tight and I'm using thin CA for most everything. I'm asuming it holds as well if not better.........Hope I am not making a bad assumption!

Sean

Mustang Fever

My Feedback: (2)

Sean:

The thin CA will work well on balsa to balsa with a tight fit. However, I have developed the habit, after building several SIG kits, of going over each joint several times until the CA starts to build up on the surface. It's either that, or I'll use the thick stuff (with kicker) to form a fillet at every joint. Glue is very light compared to everything else we put in the airplanes. The trick is to make sure every piece is bonded to every other piece. SIG stresses this in their instructions and it sorta took.

Redwulf__34

Bob,
So do you actually countersink the nylon bolts? I was thinking that I might not get that "fancy". I have some nylon bolts with a fairly flat head I was going to use. I thought I might just put in a small section of 1/16" ply where the bolts drill through. I didn't want to add it to the top of the balsa sheeting. What I thought was to just "splice" it into the top sheeting at the bolt location. Is there any reason I can't do it that way? All my other models I added it to the top. Then I had to get into some filler and feathering to shape it in. I wanted to get away from anything like that.

Hoping to get some work done today! It's raining out here. Temps are coming up to the mid 70's and we got rain! Spring is here!!!!

Sean

Mustang Fever

My Feedback: (2)

Sean:

What you describe sounds good to me. The amount of drag the bolt heads will add is very small compared to that big, thick airfoil.

I'm gonna fly tomorrow! Wanted to today, but it rained all night and it's still hazy.

I put a Cline proportional fuel system on the Stik last week, and the engine can now be set to peak before takeoff, and will stay there, regardless of attitude or fuel quantity remaining. If it flies as well as it does on the ground, I'm going to start using them on all my birds. Two stroke engines are such a value compared to anything else out there, it's a shame that many people have problems with them. About 99% of those problems have to do with insuring an adequate fuel supply. Cline has been selling these things since 1990, there must be something good about them.

Mustang Fever

My Feedback: (2)

Sean:

Guess you can tell by the pix I went flying yesterday.

The Cline system must not be adjusted quite right. Engine ran fine for more than a half tank, two landings, and a lot of aerobatics including vertical. Then it quit during a vertical, and I lost track of the (*&^%$#@ electric fence by the horse paddock. It went under the lower wire after touchdown, during rollout, clipping the pole with the wing and the landing gear. About half the landing gear block ripped out of the bottom of the fuse, and the left wing panel was amputated even with the flap. No other damage.

I think I'll just start busting them up right after they're completed. That way, I skip the intermediate step and get right to the repairs. Whaddaya think?

Redwulf__34

Oh my! Well, part of the flying is the building! I know my old sweet stick went through a ton of what your doing now! I had a bomb rigged to it with a drop. I remember the first crash. We had a spot on the runway seeing who could drop the closest to it. I let my buddy have his turn and he was more interested in where the bomb fell than where the plane was going!!!!!! Need i say anymore??? [>:]

I didnt' get a bit of work done this weekend. The rain never came so there was a lot of playing outside and not much work going on inside! I'm thinking about these wingtips. I think I may run the 1/4 all the way back and eliminate the 1/16 sheeting. I can just shape the 1/4 at the rear a little and just let the covering do the rest. How did you do your tips?

Good luck with the repairs! Remember your building character into the plane now!

Mustang Fever

My Feedback: (2)

Sean:

That's exactly how I did my tips.

Yeah, I'm gonna make up some tree and fence decals for the nose to represent my "victories".

Redwulf__34

Bob,
How did that Dubro tailwheel assembly work? Do you need any blocking in the horizontal stab for it? I'm re-thining my trike gear.............

Sean

Mustang Fever

My Feedback: (2)

Sean:

I put some sheet balsa near the TE of the stab to fill in the gaps between the sheeting, then inserted two 5/8 dowel plugs on the screw centers for the TW. I set the whole thing up so that the TW strut is almost vertical coming out the bottom, and goes up through the stab and the bottom of the fuse even with the TE of the fin. I waited until it was installed and I was ready to hinge the rudder before bending the end of the strut over to fit into a hole in the bottom of the rudder, so when the rudder moves, the TW steers.

Don't know if that makes any sense. The pix might help.

Redwulf__34

Well, not much happened here the last few days. I've been busy at work and a couple birthdays back to back! Time to get back because the flying weather is here!!!!!!!

I need a little help. I want to use a single servo with torque rods for the ailerons. I'm not sure how to do it since the ailerons basically attach to the TE. There is no place to "hide" or "hinge" the torque rod. Any ideas? I've always used them but usually the aileron is set inside the TE and the torque rod "hides". I've had a few ideas but they aren't very good. Does someone make something that would work like a hinge? Something that I could insert into the TE and it would "wrap" around the torque rod?

Sean

jatik

Hi Redwolf,

Back to early 80's when we had "Stick" we used to use Bicycle spokes as torque rod.

- take spoke, bent it 90 deg on thread end (see picture), insert longer end of rod into suitable plastic tube (which is to glue with epoxy onto TE, check that length is correct), then bend other end and eyeball the place where you fix this to aileron strip.....

Bicycle spokes are easy to get, cheap, strong, allready threadded...

On this picture there is pictured dubro 3/32 aileron system or use heavy duty ones 1/8... up to you.. they cost you on LHS like 3-5US$

Mustang Fever

My Feedback: (2)

Sean:

Is there enough width in the TE near the center of the wing to cut off about a 1/2 inch wide strip to use as a torque rod hider? If not, I think you'd be better off to go with a pair of servos.

I always liked torque rods for their simplicity and lightness, but the wing has to be constructed with them in mind.

Redwulf__34

I really don't want to use two servos. I'm gonna try to add to the TE like you suggest bob. That is my idea. There is no issue with the wing, my bigger concern will be how to tie it to the fuselage. If I had been thinking earlier I would have added a little height to the rear of the fuselage to accomodate it. Ideally, if there was some type of tubing like Jatik is showing above with a flat. If there was a "tube" that wrapped around and had a "flat" that could be "slotted" into the trailing edge like a hinge that would be great and simple. I'm not sure how well epoxy will hold the tube to the trailing edge.