Yes, another Javron cub

[bcone1381]

Thanks, guys. Do you use something like a 10 oz cloth or what? How do you finish it? Gel coat or just fill and sand or something else?

Wayne

Use Rutan Bi-directional 7725 cloth. I think is 8.8oz fabric. google 7725 fiberglass and youll see its common. Spruce has it. Cutting on the bias means cut it on a 45 degree diagonal. If you are worrying about waist when you cut it off the roll your doing it right.

Finishing it....
You would get a lot out of going to EAA Sport Air Workshop "Composites for Vans Aircraft" class taught by Scott VanderVeen. If you go to it you'll do this task in class and have a stronger lighter windshield fairing. I cant do it justice using this type of communicating.

But you asked.....when you order your cloth buy a pound of flocked cotton and a pound of glass bubbles aka micro balloons. Micro Balloons aka Micro is like dust particles of glass beads. So use a mask, do not breath it in. Mix up your epoxy like you lay up some glass cloth, then start adding in the Micro. it will take about 5X volume of Micro to Epoxy. ABout 5.5OZ of Micro to 1 pump of West System Epoxy. mix in a little at at ime until its like cake frosting and the tips of it done fall over. We call the mixture of Epoxy and Micro Balloons "Dry Mirco" when the mixture has so much Micro that the mixture looks dull for 3 to 5 seconds after you stop mixing it.

Now frost your window fairing like your frosting a cake and let it cure. 8 hours at 70F or 3 hours at 120 F if you can get it warm. Then sand it with 80 grit and the corner of a small block of wood as your sanding block on 45 degree pattern across the line of the fairing.

I attached a photo. I did this last week. Its not for the windshield. I'm modifying a vans cowl scoop to fit my cowl. I first fabricated a sharp fillet of 50-50 ratio of Flox and Micro mixture becuase Micro is not structural, Flox is. But flox wont sand much at all, Micro sands fabulously. I then immediatly applied two layers of Epoxy impregnated cloth over the fillet let it cure. Then I applied a 20-80 ratio of Flox - micro over the top of the sanded glass cloth to form a gentle fillet and immediatley applied two more layers of glass cloth. Let it cure. Then I frosted it, sanded it, and did it two more times to get it looking good. I dont have a photo of that part handy.

If you dont sandwhich the fillet then I'd use more than 4 layers of cloth. Bob Barrows calls for 8-10 layers for the Bearhawk Patrol fairing. I bet the sandwhiched process is lighter and stronger and and better looking.

 

[bcone1381]

This is what a frosted part looks like after it cures, and then after its sanded.

 

[bcone1381]

. ABout 5.5OZ of Micro to 1 pump of West System Epoxy. mix in a little at at ime until its like cake frosting and the tips of it done fall over. We call the mixture of Epoxy and Micro Balloons "Dry Mirco" when the mixture has so much Micro that the mixture looks dull for 3 to 5 seconds after you stop mixing it.

Not 5.5OZ, rather units should be Grams. 5.5g to one pump.

 

[Skywalker]

When adding filler to epoxy adding too much filler means pumping up another minimum batch of epoxy to liquify the mix a bit. So you waste time creeping up to a mixture that will not run. (Thixotropic mixture) Somtimes I think its too thick and it still runs. Adding colloidal silica when you get close makes a reliably thixotropic mixture that still seems sorta wet. Much less critical. West has it , the boat builders call it Cab-O-Sil.

 

[Mr. Ed]

This is what a frosted part looks like after it cures, and then after its sanded.

View attachment 106035View attachment 106036

I use micro bubbles and fumed glass with WestSystems epoxy for filler also but I don’t put it on that thick. I go as thin as I can, otherwise it’s just more work sanding it off. It does sand well but less work is a good thing.

 

[fishhook]

I used the standard 3 inch wide clotch on a roller aircraft spruce sells. Went 8 layers deep, just rolled and padded the cloth together. Came out about .125-.140 thick, some hand sanding when done and wiped a skim coat of the beads and voila, ready for primer. Sure its a little heavier then getting all fancy with bagging it or other methods, and the standard weave laid down just fine. Its hell for stout too. Stiffens the boot cowl up a lot. Make sure the windshield is lightly strapped with a strap or bungees back into the bootcowl and backup strip when laying up the outer strip. Once you add felt and subtract the masking tape and packing tape the gap fits snug with the windshield. Also oversized the holes slightly to allow some movement for alignment. Once I bit the bullet on masking it all off, I really only had 3 hrs or so into getting it all laid up to cure. Another 2 for clean up and drilling/sanding. Less time and frustration then farting around with those aluminum strips... To make the inside backup strip you can just make a foam block that fits into that area snug and well, then use that to make the piece on the bench. Worked great! Next time I would make a slightly wider backup about 14 inches maybe 15 inches wide, and use plaster and waxpaper to make a very tight fit piece.

 

[stoldriver]

Thanks guys, for all the helpful suggestions. Put down a layer of blue painters tape and a layer of clear packing tape. I marked on the blue tape the limits of where I wanted the new retainer to be with a black sharpy. Put 3 layers of wax on the packing tape. I ordered some 7725 and started cutting strips on the diagonal. I figured I needed about a 2.5 in strip so I measured and cut a strip. Took it to the windshield and all of a sudden, it was maybe 1.5 in. Turns out there is a lot of pliability in this fabric which is probably why it was suggested. So back to the cutting table and I figured out how many threads I wanted (about 32 gave me the width I wanted). I wound up using the narrow fabric strip (plus another one) below the windshield so I didn't have as big of a step. My next mistake was to mix up a 6 oz batch in a solo cup. Started laying tapes and it seemed OK at first but the batch cooked off, melted the solo cup, and made a mess. I'm in Phoenix area where it is currently pretty warm and very dry and I think that made it go sooner. Mixed another 6 oz batch (I never learn) but at least this time I used a paint mixing cup. Still cooked off before I was done but didn't melt the cup and didn't make as big a mess. Made a smaller batch and finally finished laying 8 layers (not counting the narrow layers I put below the windshield). I think 8 layers is too much. Four probably would have been plenty. Rolled it with a ridged roller to get the air out and let it set for a day. Came off pretty well. I did some initial trimming with a multi-tool using a saw blade and then a sander. Put it back up and used a hole finder to drill all the mount holes. Marked where I wanted to trim to and trimmed again with the multi-tool. Mixed some micro balloons with resin and hardener and did a skim coat on the out side and sanded that to a finish. I'll have to drill the holes out again. Seems to be ok. It's a bit heavy but not too bad.

Also worked on a sight glass. Looks like this which I believe is more or less how atlee dodge does it. I took mine all the way over to the fittings in the tank. I'll have to check it often to make sure it works out.

Wayne

 

[bcone1381]

Cutting the fabric on the 45 degree bias is exactly right. Next time
-put a large piece of 4-6 mil plastic down on your work bench,
-cut a piece of glas cloth oversize and weigh it (lets say you have 6 oz of fabric),
-mix up only that much epoxy (6 oz in this example) and dump it on to the fabric.
-place a top piece of plastic over this mess.
-Push the epoxy into the fabric using a bondo spreader or hotel key card (or your drivers license...haha) a 1 in diameter steel tube rolls it out nice too.
-Now, mark out the shape you want...like you wanted a 3.5 inch strip to cover your 2.5 inch wide finish dimension of your windshlied retainer.
-so far you have no mess....just cloth and epoxy between visqueen plastic.
-cut the shape you marked out with scissors, and take it over to your windshield joint....remove one side of the plastic and lay it down as you remove the top piece.
-Take a throw away paint "chip brush" and make sure your glas/e[poxy fabric is free of bubbles and in exactyl thte right location.

I don't like to pre-impregnate more than two layers of glass cloth at a time. But you can impregnate a number of strips at one time. Also, when you dump out your epoxy it cools so it wont thermally run away and get hot on you.

You will have very little waist epoxy by weighing what you will use. 95%.of the time will not need to add more to the layup. I try to leave a small amount in the cup so when I hit with the chip brush I can add a bit more epoxy to the layup if its dry.

 

[stoldriver]

Thanks bcone.
Covering turns out to be somewhat therapeutic for me. Kind of like doing it. I decided to use Stewart's system. All of the control surfaces have now been covered plus the door through silver. Started with the bottom side of the stabilizers which won't be seen so much. I definitely learned as I went and the last pieces are better than the first. As soon as I get the wings back off, I'll start on the fuselage and prep the wings.

Things I've learned so far - I ordered direct from Stewart's and went by their recommended super cub quantities. It said it should take 50 yards of fabric. That probably is plenty if you know what you are doing but I don't. I'd probably say order at least 55 yards, maybe more. Fabric is fairly cheap per yard but shipping it is not, so order plenty. You can probably get 5 more yards for the price of that second shipment. I probably use more anti chafe tape than I should but I also found this quantity to be low. I used up the single roll pretty quickly. I could also see that I would run out of grommets pretty quickly. Their list included 50 seaplane grommets. I ordered a bunch of standard grommets and will put those anywhere I don't think water will be such an issue. For instance, I used seaplane grommets on the flaps but used standards on the ailerons. I've also wound up buying more 2 inch pinked tape. Again, I probably use too much but there it is.

I am a cheap skate which sometimes translates into I spend more than I would have if I wasn't. I decided to try to save money on the iron and bought a Toko T14 ski wax iron. It's a great iron, digital and all, but will only go up to 330 degrees. Since pretty much every system says to take the fabric to 350, I questioned myself for about a month before I finally just broke down and bought a Fabric Pro iron.

On the surfaces done so far, I brushed diluted glue over all of the white like the directions said. I sprayed the silver outside the hangar one side at a time. Picked up some crap in it but it all gets sanded anyway. Sanded between each of 3 coats. I will sand the last coat when I'm ready to prime it.

I've used poly fiber a little bit and it's great but it can be difficult here in Phoenix to get the fabric to the glue while it's still wet. That stuff flashes pretty fast when it's over 100. That's not an issue for a lot of the time with Stewart's. You let the glue tack up anyway before positioning the fabric. You lay tapes in to wet glue but you can do it in small enough lengths that it doesn't seem to be an issue. Then there the mask thing. Using mek, you should mask up every time. I've been able to go all the way until spraying silver without masking up. I pretty much decided not to use polyfiber early on but waffled between Stewart's and Aerotech for quite awhile. I think acetone is a lot better than mek but it's nor exactly benign so I eventually settled on Stewart's.

Bad things about Stewart's, the glue cleanup can be a little bit of a pain. Literally. The easiest way to remove it is with the glue eraser and it works very well, but if there's any hair where you have to erase glue, there won't be when you are done. Also, if you get it on your clothes, it's there forever. Also also, if you are like me, you will inevitably spill a little cup of glue on the floor. If that happens, just plan on spending some time cleaning it up. Other than that, I really don't have much negative to say. I can't speak to longevity of the cover yet, of course.

Wayne

 

[bcone1381]

Tools for Glue application.....
I ditched the cup/paper plate thing after I knocked it/spilled it a few times. I switched to using 30ml dropper botttles. I used less glue, it was quicker with the bottle. Just apply it on the parts and then spread it with the chip brush. when I knock it over its ok. When I forget to place the cap back on, its easy to clean out and no glue dries inside. With the cap on the bottle the glue stays fresh for months. I bet glue consumption when down +15%

 

[Gary Raser]

I have just bought a set of wings from Javron for my experimental PA-11. I really like the workmen-ship. I am also using Stewart system. I am not ready to cover them yet but was wondering if there is any prep to the aluminum before covering?
Thanks

 

[stoldriver]

I usually just wipe it down with acetone prior to glue application to make sure it's clean. I couldn't find anything in the manual saying to do anything special but I figure cleaning is a good thing.

Wayne

 

[Gary Raser]

Thanks I’ll do that

 

[stoldriver]

Took the wings back off awhile ago to start prepping for cover. I thought I had everything done that I needed the wing on for but I did not figure out the window latch. Soooo, I put the wing back on and marked where to install the latch. Made a doubler plate with nutplates to screw it onto and then bonded and riveted the doubler inside the leading edge.

Wing covering is a fairly long job for me. First, putting everything into the wing that needs to be in there before cover. For me on my rh wing, that meant the doubler mentioned above, lite bracket, magnetometer, wiring for those two, aileron control cable down the front spar. It's probably easier if the other aileron cable is in there too, but I fished it thru. I did put it in the lh wing before cover. I did the cover with the wings sitting on a couple of tables. Worked out OK but did wind up on the floor underneath a few times to do something. I found that it was important to take some care how you support the wing on the tables. Parts of the wing are plenty strong to rest on but some, like the tabs for the jury struts, are not. I pretty much followed the YouTube videos for covering wings with Stewart's. There are details they don't really cover tho. Anti-chafe tape was easy enough, but one spot that I probably should have put it was on the aft spar on the bottom of the wing tip. The fabric is basically touching. I did put a finish tape on it outside. Cable exits are something to be careful with. I thought I had it figured out by measuring when I had it all rigged on the fuselage and took photos. That was a number of months ago and some of my photos were a little cryptic. I wound up with some holes bigger than I wanted, not that anybody can see them, but I know. It's a thing to really pay attention to if you want minimal sized holes. The area around the strut fittings wound up not being very attractive, especially the forward one. Functional, yes, pretty no. Turned out a little better on the second wing. Here's how I installed the strut fillers. The little one has a couple of rivets holding it. No way to dimple it but since it is completely non- structural, I just csink'd it. I think a universal head rivet would be fine there tho. The big one I essentially just taped in place with good foil tape and a couple of rivets into the flange of the leading edge. I noted in another thread that Steve puts them in after putting fabric on. I did them after. Not sure what advantages either has but I suspect Steve knows more about this than I do.

Stitching was done just like that young blonde girl on YouTube with the island and the palm tree. I watched a whole bunch of videos and that one just seemed easier to remember. I started the first stitch 1 inch behind the forward spar on the RH wing which turns out to be probably the worst spot. There's a bunch of stuff going on right there and I ended up moving the first stitch a few times so the starting stitch is not consistently located. The time to think about that is before you start, not after like I did. I used my rivet spacer to mark stitch location every so often and a straight edge to mark the ribs between.

I tried to do a thorough layout of the tapes. I even numbered on the fabric to remind me which tape went first. Mostly came out OK but I struggled a little with what locations needed them. I also had a few places where, after I was done, I thought I should have laid that other tape first instead of the way I did it. I doubt my boo-boos will be as evident after painting.
Wayne

 

[fishhook]

I would put the rectangular inspection plate or make the whole bay at the flap bellcrank a panel. Flap spring changes will then be a cakewalk.

 

[stoldriver]

I thought I had a picture but can't find one. I put nutplates in on the top side to screw on a rectangular cover over the flap spring. Thanks.

Wayne

 

[phdigger123]

I thought I had a picture but can't find one. I put nutplates in on the top side to screw on a rectangular cover over the flap spring. Thanks.

Wayne

Something like this?

 

[stoldriver]

Pretty much but I think mine is further outboard.

Wayne

 

[stoldriver]

As an additional update, I received my engine recently. Ordered from Titan July 18, 2023. Received Nov 4, 2024. I only got it that early because I finally gave up on the magnesium sump and no, I did not get a discount for going to the aluminum. I ordered mine with a carb and e-mags. Oddly enough, it came with the auto spark plug leads from e-mag but did not come with spark plug adaptors or spark plugs. I've temporarily hung the engine with a plexiglass firewall and am currently installing sensors and laying out the firewall penetrations plus figuring out how everything else goes in forward of the firewall. I'm thinking maybe I should use this oil cooler. should keep it cool here in the summer.

Wayne

 

[bcone1381]

Tell us more about your oil cooler choice.

 

[stoldriver]

That one's from a Wright 1820. Might have to upsize my oil pump.

Wayne

 

[stoldriver]

Received my engine in October and hung it pretty quickly after that. Used an acrylic "firewall" and have been laying out where firewall penetrations will be. I have purchased two cabin heat boxes from spruce and mounted one on each side with the intent that one would be front seat and one back seat. Two control cables from spruce which are the A730 glide free cables. Also bought an A740 ratchet cable for carb heat. The exhaust is vetterman which installed easily. Vetterman says to pick up a couple of sump bolt for supports but I tried a few different ones and didn't like the geometry so I clamped both supports to the mount. I drilled all of the exhaust pipes for egt sensors and installed them plus cht, carb temp, oil temp and press, manifold press. The egt sensors call for a press fit for good sealing. So you shouldn't be able to just drop them in. I wound up using a little persuasion in the form of hammer and punch to gently get them down to the flange which the instructions say is ok. Installed the two solenoids and the voltage regulator on the aft side of the firewall and a shunt on my avionics shelf. Just received yesterday my b&c alternator and will install it right away. Installed fuel flow sensor on a little bracket that goes on the engine side of the fw. Fabricated flexible fuel lines using Phenix along with their firesleeve. Using a Vans gascolator so the lines go from there to the fuel pump inlet on the engine then fuel pump outlet to the red cube then red cube to carburetor.

Speaking of control cables, I ended up doing some things that weren't exactly planned. I purchased a throttle cable I'd seen recommended online, spruce a920, I believe, in the 5ft length. Nice enough cable and has 10-32 ends. I put a 10-32 rod end bearing on the carb end and that worked as planned but on the other end, the throttle handle has a 1/4 in hole. I couldn't find a rod end with a 10-32 thread and a 1/4 in hole so I put the 10-32 one on. Problem now is the .19 bolt is in a .25 hole in the handle. My solution was to fabricate a step bolt. That worked out pretty well. I also started with the cable mounted in the lower hole and the connecting rod in the upper but I had some issue getting enough throw at the carb and I swapped them to get more arc length. This worked except now the interconnect rod was lower and contacted the usb power outlet that I mounted in the throttle box so that had to move. I purchased the mixture cable after all this so I very smartly bought a cable with a .25 thread on the end so I could put a .25 rod end on the carb end matching the lever arm on the carb. Problem is the fixed solid section at the end of the cable is longer than I figured. I've got it working but the bend radius of the cable at the firewall is a little tighter than I like. In addition, I put an970 washers on the bearings to retain them if the ball/ housing interface fails. Well, a 1/4 in 970 washer is pretty big and the area at the mixture arm is pretty small so there was contact of the washer before the stop. I drilled out a #10 washer and that worked out OK and is still big enough to retain things. Not ideal and maybe rod end bearings weren't the cats meow for this.

Future plans are to continue firewall planning. I've got to come up with an oil cooler solution that fits and might allow me to fly summers here in Phoenix. Once that's figured out, I'll pull the engine and gear off and cover the fuselage. That's pretty much the only thing left to cover. Once it's covered, I'll start bolting things up to it for real. Somewhere in there, I have to build the cowling and baffling, too.

Wayne

 

[skywagon8a]

The exhaust is vetterman which installed easily. Vetterman says to pick up a couple of sump bolt for supports but I tried a few different ones and didn't like the geometry so I clamped both supports to the mount.View attachment 110132

The exhaust should be mounted to the engine since it moves with the engine. The mount doesn't move. Also the clamps around the exhaust pipe should be a slip fit. There is a lot of heat expansion and shaking on those pipes. What is there to prevent those blue hoses from sliding on their tubes? Those hose clamps are only fooling you. Exhaust pipes which are incorrectly supported can crack and break on the first flight around the airport, even new ones. Their fit is more fussy than one imagines. They must be stress free.

View attachment 110136 Not ideal and maybe rod end bearings weren't the cats meow for this.

These rod ends are difficult to get tight in the center because when you tighten the jam nut the "wrong" piece moves a bit. If you start with the ball end against the side as shown, then tighten the jam nut, it will usually end up near the middle where you want it. You have to fuss with it, but try to get it near the center where it should be.

 

[Skywalker]

I was thinking the exhaust mounts are too stiff because the bits of hose are in push-pull instead of bending. Almost impossible to have enough give and provide any meaningful support.

 

[hotrod180]

Received my engine in October and hung it pretty quickly after that.View attachment 110129 Used an acrylic "firewall" and have been laying out where firewall penetrations will be. I have purchased two cabin heat boxes from spruce and mounted one on each side with the intent that one would be front seat and one back seat.View attachment 110131 Two control cables from spruce which are the A730 glide free cables. Also bought an A740 ratchet cable for carb heat. The exhaust is vetterman which installed easily. Vetterman says to pick up a couple of sump bolt for supports but I tried a few different ones and didn't like the geometry so I clamped both supports to the mount.View attachment 110132 I drilled all of the exhaust pipes for egt sensors and installed them plus cht, carb temp, oil temp and press, manifold press. The egt sensors call for a press fit for good sealing. So you shouldn't be able to just drop them in. I wound up using a little persuasion in the form of hammer and punch to gently get them down to the flange which the instructions say is ok. Installed the two solenoids and the voltage regulator on the aft side of the firewall View attachment 110133and a shunt on my avionics shelf. Just received yesterday my b&c alternator and will install it right away. Installed fuel flow sensor on a little bracket that goes on the engine side of the fw. Fabricated flexible fuel lines using Phenix along with their firesleeve. Using a Vans gascolator so the lines go from there to the fuel pump inlet on the engine then fuel pump outlet to the red cube then red cube to carburetor.

Speaking of control cables, I ended up doing some things that weren't exactly planned. I purchased a throttle cable I'd seen recommended online, spruce a920, I believe, in the 5ft length. Nice enough cable and has 10-32 ends. I put a 10-32 rod end bearing on the carb end and that worked as planned but on the other end, the throttle handle has a 1/4 in hole. I couldn't find a rod end with a 10-32 thread and a 1/4 in hole so I put the 10-32 one on. Problem now is the .19 bolt is in a .25 hole in the handle. My solution was to fabricate a step bolt. That worked out pretty well.View attachment 110134 I also started with the cable mounted in the lower hole and the connecting rod in the upper but I had some issue getting enough throw at the carb and I swapped them to get more arc length. This worked except now the interconnect rod was lower and contacted the usb power outlet that I mounted in the throttle box so that had to move. I purchased the mixture cable after all this so I very smartly bought a cable with a .25 thread on the end so I could put a .25 rod end on the carb end matching the lever arm on the carb. Problem is the fixed solid section at the end of the cable is longer than I figured. I've got it working but the bend radius of the cable at the firewall is a little tighter than I like.View attachment 110135 In addition, I put an970 washers on the bearings to retain them if the ball/ housing interface f

 

[hotrod180]

I've seen where people use a see-through panel mock-up for layout purposes,
but I think this is the first time I've seen a clear firewall mock-up like that.
Good thinking!

 

[stoldriver]

Pete, there's an awful lot of vetterman exhaust systems out there using pretty much what you see in these photos and I haven't heard a ton of bad press on them. Vice versa, actually. They are usually pretty highly praised except for maybe the cabin heat output. Once I squeeze down on the clamps, I can't move the rod inside of the flex tubes. I'll see how it works out. I will, of course, carefully monitor everything during testing.
Wayne

 

[Bill Rusk]

Wayne. Two thoughts.
1) They don't put out squat for cabin heat. Just basically none.
2) They block a lot of exit air making it tough to get your CHT's down.

Hopefully it will work for you.

Bill

 

[tackdog]

Pete, there's an awful lot of vetterman exhaust systems out there using pretty much what you see in these photos and I haven't heard a ton of bad press on them. Vice versa, actually. They are usually pretty highly praised except for maybe the cabin heat output. Once I squeeze down on the clamps, I can't move the rod inside of the flex tubes. I'll see how it works out. I will, of course, carefully monitor everything during testing.
Wayne

I installed the Vetterman exhaust hangars on my Cub last weekend (although I'm using a slightly different exhaust). I mounted two of the small lugs onto the rear sump bolts, then added that cross piece that ties the two hangers together, so everything is only attached to the engine. I used my old pipe flare tool that I grabbed from some hot rod shop, to stop those clamps slipping off. A few local RV's have had those hoses slip over time - yet none of them either flared or crimped those pipe ends. Another friend, simply drilled some small holes into the ends and fitted some screws - I guess some big headed pop rivets may achieve the same?

 

[phdigger123]

Wayne. Two thoughts.
1) They don't put out squat for cabin heat. Just basically none.
2) They block a lot of exit air making it tough to get your CHT's down.

Hopefully it will work for you.

Bill

I have the Vetterman exhaust on my Javron. I installed front heat from one muffler and an additional air box to draw heat from the second muffler for rear heat. I can fly at 0 F in just a sweat shirt and be comfortable. I have no problems with CHTs. I typically run 350 to 375 in the summer here in Minnesota. I really like my Vetterman. I wish I could put it on my certified PA18.