N200LZ: Chapter 14

[TMann]

I figured while I was waiting for micro to cure, I'd get started on Chapter 14.

I built the spar jig today. I took my time with it. It gets a little hard to get those cuts just right.

8.41, 7.35, 6.12, 32.87 DOH! I cut that one at 32.86"

Do over!

[rickh]

Small world... I just bondo'd my jig to the table a few minutes ago.

 

Rick

[TMann]

I got my Crush Plates layup done today and it's curing in the vacuum bag as I speak. I cut two pieces of MDF (left over from jig construction) at 24 x 15. I put down a piece of poly then peel ply followed by 15 plies of BID 11.5 x 20. Followed that up with peel ply, perf ply, breather/bleeder and another piece of poly. I put the other piece of 3/4 MDF on top, added some duct tape to keep it from shifting and popped the whole works into the vacuum bag.

 

No need to add weights to it. The atmospheric pressure will 'crush' the crush plate.

 

When it's cured I will cut it into two pieces measuring 5.4 x 19 .

 

NOTE: This step is required for the Infinity Retracts.

[JTest]

G'day

 

I have been working on my spar for almost 7 weeks now. I hope to have it finished this week. I only have the end cap lay-ups and the cuttting of the opening for the centar section left.

 

Be sure to cover the jig with plastic wrap! I only used Duct tape on mine and the micro had bonded with the jig.... As TMann said do over. Yeah, I had to recut and redo the whole thing....

 

Now that it is almost done it looks pretty good. I used the BID lay-ups until lay-up 8 and then used the two layers of UNI for the front.

 

Jeff

[gullikson]

Well, it looks like a few Longs will hatch sometime in the not-too-distant future. I am going to start building my centersection spar jig towards the end of the week. It will be good to have another couple of builders with recent spar time to talk to should there be any questions. Looks pretty straight forward. Any comments on any section of this particular part of the build would be welcome.

[rickh]

... Any comments on any section of this particular part of the build would be welcome.

Don't know about the Long, but the Cozy destructions say to precut the interior bulkheads 'in advance' then install during the initial one big layup.

 

If I had mine to do over again, I'd make them a skosh tighter, then use a bar clamp between the 'rear' spar jig and the 'front' urethane foam (with a 1x board skid under the clamp) so they stay tighter when I'm glassing them in.

 

Rick

[JTest]

G'day

 

If I had to do mine again I would not use the Urithane foam! Use 1" foam that was used on the fuselage. I have been reading old changes/mods and many folks have said the Urithane foam delaminates and is a pain....

 

Oh, don't miss the templates for the spar Uni lay-ups (page A-11) for Open EZ and Long EZ drawings. Figure around 70 hours to complete... It took me about 80 hours and I still have another 10 or so to finish the last lay-up and cut the center section out.

 

Feel free to ask me any questions. I may have already learned the answer, but then again maybe not....

 

Jeff

[TMann]

I cut out all my hard points (aluminum) after work. I treated them with alodine and should be ready to install them this weekend. Once I get the first couple of layups done I'll have to wait a couple days for it to cure which should give me the time I need to put the top spar and skin on the canard.

 

It would be great to put a lid on 10, 11 & 14 by the end of the month.

[JTest]

I cut out all my hard points (aluminum) after work. I treated them with alodine and should be ready to install them this weekend.

 

G'day TMann

 

How are you treating with alodine? I looked into the process, but it looked like several large tubs of chemicals for only a few parts. I welcome your solution if it is different.

 

I did the last end BID 45 degree lay-up on my Open-EZ project, Thursday. I will trim the 2 1/4" access hole later today and will put the spar to the side. I have a hanger move in the next couple of weeks and need to pack everything....

 

I have lots of parts that need to be stuck together when I get back from OZ in September. I won't get much more done until then...

 

Thanks

 

Jeff

 

Thanks

[TMann]

Here's the description from the Wick's site:

ALODINE Brush-on chemical to condition aluminum for paint, to improve paint adhesion and corrosion resistance. After precleaning with Alumiprep #33, apply full strength with brush or sponge. Rinse with water and surface is ready for painting. The visible coating leaves the surface with a golden coloration. One quart treats approximately 100 square feet. Meets Mil-C-5541B, Class 1A, Method B. Store above 40 degrees.

 

After sanding all sides, it's a great time to drop the pieces in an alodine bath. I use a brush on the surface as it sit's completely covered in the stuf and then rinse it off.

 

I believe it is a good practice to protect these parts. With any luck, I'll never see them again.

[TMann]

I finished up the additional work for the Infinity R/G.

 

I'm looking over the (Step 6) shear web lay-up and they call out 3 plies of BID with 1 inch overlaps...... which is extremely wierd when compared to the instructions for the shear web on the canard or wing.

 

I looked at the AeroCad instructions which call out 4 plies of UNI at 45 degrees in a criss-cross pattern. I have to believe this makes for a smoother layup than the BID with overlaps ........ not to mention stronger.

Even if I had to go 6 plies, I would feel better about the part than to use the method in the plans.

 

Sound reasonable?

[Marc Zeitlin]

I'm looking over the (Step 6) shear web lay-up and they call out 3 plies of BID with 1 inch overlaps...... which is extremely wierd when compared to the instructions for the shear web on the canard or wing.

Could easily be that that's what Burt and Mike had laying around when they got to the shear web for the main spar.

 

I looked at the AeroCad instructions which call out 4 plies of UNI at 45 degrees in a criss-cross pattern.

Yep. That's the COZY scheme, which AC copied (hell, they copied 98% of the plane :-) ).

 

I have to believe this makes for a smoother layup than the BID with overlaps ....

Smoother, maybe, although smooth is hardly meaningful for something that's never seen.

 

... not to mention stronger.

And you shouldn't mention stronger. There's almost exactly the same amount of fiberglass in two layers of UNI as there is in 1/2 of three layers of BID, measured both by weight and by thickness. Any differences in strength due to the different glass weaves will be swamped by differences due to builder skills.

 

Even if I had to go 6 plies, I would feel better about the part than to use the method in the plans.

While you might feel better about it, there wouldn't be any technical reason for you to do so, and you'd be adding weight for no reason.

 

Sound reasonable?

Nope.

[TMann]

There's almost exactly the same amount of fiberglass in two layers of UNI as there is in 1/2 of three layers of BID, measured both by weight and by thickness. Any differences in strength due to the different glass weaves will be swamped by differences due to builder skills.

... okay, so am I to assume that the same layup/method used in the afore mentioned design (AeroCad/Cozy) would be acceptable for my Long=EZ bird.

[Marc Zeitlin]

... okay, so am I to assume that the same layup/method used in the afore mentioned design (AeroCad/Cozy) would be acceptable for my Long=EZ bird.

Certainly should be - they both weigh more than the LE, so the loads in the shear web will be larger. Given the almost identical construction methodology and design, I can't imagine why using the COZY layup schedule in the main spar shear web wouldn't be adequate for a LE, even given the theoretical differences between the max G loads (4.4 vs. 5.0). If I had a Long-EZ, I'd limit it to the Normal category (3.8 G's) anyway, given the inconsistencies in the V-N diagram and V speeds.

[TMann]

Certainly should be

Thanks Marc.....you da man!

 

The 6 plies quote in my earlier post referred to ' If I had to go to that level to be safe, I would be okay with it'

I was digging for my hexcell spec sheet without any luck.

(Back to work)

[JTest]

G'day TMann

 

I wish I had known about the BID vs. UNI when I built mine in June/July. I think the finished spar was around 54 lbs according to the bathroom scale.

 

I looked back and see I forgot to thank you for the Alodine post. I followed up and purchased it from Wicks. Thanks. I am using it to treat the aluminum parts I am making for the carard (Chapter 10) I am building.

 

What has been your delay on the spar? I see you started in July. I moved my shop to another hanger back in late July and then took the family to Oz and Fiji to visit rellies in Aug. Had to rebuild the shop Sep and 1/2 Oct. Hope to finish the canard, Chapter 10, this weekend....

 

Thanks again for the advice!

 

Jeff

[TMann]

I wish I had known about the BID vs. UNI when I built mine in June/July. I think the finished spar was around 54 lbs according to the bathroom scale.

I know what you mean. It just didn’t sound right to me. I didn’t like the lack of continuity of the BID approach so I started checking some other resources.

The data sheet from Hexcel is located here:

http://www.hexcel.com/Products/Downloads/Fabrics+Data+Sheets.htm?map=P1&t=Fiberglass+Data+Sheets

Four layers of the UNI measures out to 30.8 mils and a combined weight of 29.2 oz/yd

Three layers of BID measures out to 27.9 mils and a combined weight of 26.4 oz/yd

No overlaps and a continuous fiber seemed like a better Idea.

What has been your delay on the spar?

 

Yeah ...... I got stalled out on this.

When I built my house I built a basement (“the bunker”) under my garage. I ended up with a 750 sf shop area that's pretty descent to work in. I got flooded out this summer and had to tear up the driveway in order to get to the area where they cut out around the garage doors. They left a seam about 10 inches below grade that they never sealed properly.

After fixing the problem, I added a drain tile that slopes to daylight so that should be pretty solid now.

While I’m working on finishing up my spar and canard, I’m also trying to wire and insulate “the bunker” before I move back in. Currently I’m in the basement of the house. Anything I can weasel through a set of double doors, I can get in and out. In other words….. I have to be back in the garage by the time I get to the strakes. I can get out with one strake finished but not two.

[TMann]

I had a pretty good weekend. I floxed in my aluminum hard points, installed the shear web and also the top spar cap.

I'll have to hold off on the bottom spar cap until the weekend. I had to order more tape.

[TMann]

My Spar Cap on the Center Section Spar seems to be a tad shy of the top of the foam (say 1/16th). I added all the proper layers but I think I could even add 1 or 2 full length spans to bring it up .............. or should I trim the foam to the top of the spar cap and move on?

 

I use a heatgun when I do the spar caps and I think I'm ending up with a layup that has very little excess epoxy which is good but I noticed with the canard, I ended up putting in more tape than was called for in the plans by maybe 25-30%.

 

Any thoughts?

[TMann]

I measured and it looks to be about .08 shy towards the ends and .16 towards the center of the spar.

 

Am I overly concerned??

[Marc Zeitlin]

I measured and it looks to be about .08 shy towards the ends and .16 towards the center of the spar.

Since the COZY/Aerocanard plans (which were pretty much direct copies of the LE plans) state explicitly in Step 6, Spar Cap Layups, that:

 

"It is acceptable to use one or two layers more, or one or two layers less, to fill up the trough."

 

I'm not sure what your question is (unless the LE plans don't have that disclaimer). Follow the plans. If they don't say that, then just put on one or two more layers.

[TMann]

Yeah .... they don't say that but that fits right in with my logical side. It seems much better than anything else I can come up with. I think I can fit in 1 tape almost full length, and at least one possibly two shorter lengths.

[steve]

when you add wings,engine covers, and fuel tanks, you mite add up to a 1/4 inch of mico to flatten it all out.

i think mine was lite and i could of added 2 more but did not:mad:

[gullikson]

I just finished laying up my L.E. centersection spar caps a couple of weeks ago and ended up adding one ply full length top and bottom and a couple of shorter plies on top and one shorter ply on bottom to fill the trough. Just did the 4 ply UNI over the top, bottom, and aft surfaces and bonded on the LWA's. Should have it finished soon.

I was going to start the canard or wings next but I think I'll wait till the outside temps warm up in the spring. Will be attaching the fuse sides to the bulkheads and then finishing up the fuselage assembly next. Does anyone know if Bob Davenport still sells his extended nose plans?

[TMann]

Well I added a full length ply another 100 inch and 1 to the bend and a shorter section. It looks much better.

 

I'll know better when I do the flip side later in the week.

 

I did review my Long-EZ plans and there is no mention of the possibilty of not filling the void up to the correct level. I reviewed the same process in the Aerocad plans and as Marc stated (for the Cozy plans) there is mention that the tapes may not measure out to exactly .025 once the cross thread is pulled. I can see where not only the depth would be a major factor here but also the width seeing as the object is to fill a defined volume.

 

Maybe I was off here or there. No matter.

Next step get more tape and find something to do while I'm waiting.