Chapter 14 – Mounting Spar to Fuselage
3 November 2015 — Since the weather was good, I decided to wash off all the sanding dust off my motorcycle and then cut the 4130 steel engine mount extrusions. Now, as far as I know you can’t buy 1″ 4130 angle “iron,” so I bought 1″ x 1″ x 1/8″ square tubing a couple of years ago for the engine mount extrusions. I figured I would merely cut the tubing along opposite corners and Voila, I would have my L-shape angled 4130 pieces.
About 6 months ago I called a local steel company and asked them how much it would be to have them cut these for me. They said they didn’t do it and referred me to a local machinist, who wanted nearly $200 to cut the damn things. Well, a couple of months ago a friend of mine’s elderly father unfortunately passed away and she had the small table saw below that she very graciously gave to me. Since it was a little beat up and since it’s much more inexpensive than my larger portable table saw, I would use it with a metal cutting blade to cut these 4130 square tubing engine extrusions.
Here’s the square 4130 tubing for the engine mount extrusions.
Ahh, the well laid plans of mice & men! Unfortunately the blade would flex to the side under the pressure of the hard 4130 steel so it wouldn’t really cut the corners cleanly. I played around with it for about 15 minutes before finally realizing it was a lesson in futility. With the corners thinned a bit, I grabbed my Dremel and tried to cut it freehand. Well, that’s the hardest 4130 steel I’ve seen because by the time I got from one end to the other my Dremel cut bit had disintegrated.
Ok 4130 square tubing! You won round #1, but I’ll win in the long run! Ha! With that, I moved on to more important build tasks at this point.
15 September 2016 — Today, while I had the saw out, I took the opportunity to go ahead and cut my lower 3/16″ thick angled 2024 engine mount extrusions.
Here you can see I cut the lower engine mount extrusions to the plan’s 8″ length.
16 September 2016 — Today I hit another HUGE milestone in my Long-EZ build: I mounted the fuselage to the CS Spar/Wings assembly!
First, I spent about an hour organizing & cleaning the shop. I then spent over 45 minutes cutting the BID tapes for securing the fuselage to the CS spar. I also cut out the 3″x3″ BID pads to cover up the inboard 5/8″ pilot holes I drilled on the CS Spar to facilitate drilling the wing bolt holes. Since the front face of the spar makes up the aft wall of the fuel tank, then the inboard holes clearly need to be re-glassed.
To get the fuselage into place on the spar, I needed to get rid of the sawhorse out from under the spar.
To do this with least amount of hassle and disturbance, I simple cut the 2 front legs of the saw horse. Since I had routed the water level lines through the legs of the saw horses, the most expedient way of freeing the water level tubes was to simply cut the cross members of the sawhorse. You can see all this in the pics below.
Voila! Here’s the saw horse with its front legs trimmed down and easily removed out from under the spar without disturbing the spar.
Here are the wings & CS spar, with the spar out in free space and held in place only by the wing bolts.
I then needed to get the fuselage out to the wings/spar setup. Here’s my fuselage on climb out! Of course I really lifted the nose high to get the table out from under it.
This is the first time my fuselage has ever ventured out into the world (aka “beyond the garage”).
Looks “long” with that nose on there. Love it!
Getting ready to back ‘er up.
Doing a little 3-wheelin’!
Over the storm drain & through the woods . . .
Ah, this is where this belongs! Looks awesome with the fuselage set in place on the spar. It was pretty EZ to line it up because I had taken some time when I mocked this all up in Germany back in 2013 to align the fuselage on the spar, at which point I marked the spar with alignment lines. I had actually forgotten about those alignment lines and seriously didn’t even notice them until today. What a nice surprise!
Spar is still level Left & Right.
Here’s me re-checking the CS spar level, left & right sides. I don’t have pics, but the incidence on top of the spar looked spot-on as well.
Ah, nice & level across the longerons!
Now, the nose was a bit high so I ran into the garage, got my battery and mounted it in the nose.
I then raised the nose gear until the longerons were level at 0°.
Then rechecked the left longeron to confirm 0°.
I tried to use the laser level to shoot down the CL of the fuselage, but it was just too bright out to see the laser mark, although I could see well enough to line up the spar with the back of the front seat CL mark. I then ran a string to confirm all was centered between spar & fuselage.
I do have to admit that a persistent problem that has plagued me all these years is that my fuselage has a slight twist to it. It essentially “droops” down to the front left just a hair. It’s about 0.2° low on the left side at F22. There’s nothing I can do about it, and I even tried to load up the fuselage with offsetting weights to cure (pardon the pun) this problem when I post-cured the fuselage, but it made scant difference. The main issue it causes is with mounting the canard, and it simply means that the canard may be lopsided a hair when mounted to F22. However, we’re talking about the canard being mounted maybe 1/8″ higher on the left side. This issue is one major reason why I want to mount the canard with the wings & spar in place so that it will be straight in relation to the wings! Not a horrible issue, just one to note.
All-in-all, it only took me about 30 minutes total to align the fuselage with the CS Spar. In addition to the steps above, I made a whole slew of measurements from the aft outboard corner of the spar to instrument panel & F22. Measured from the front outboard end of the wings to the the panel & F22. I also measured the aft outboard TE of the wing to the very tip of pitot tube: 247-3/4″ on the left, and 247-1/2″ on the right. I looked at all my other measurements and noted that indeed my fuselage was tracking just a hair to the right. A very small nudge on the nose and all my measurements were pretty much exact, if not within a 1/8″ of an inch off at a point or two. I remeasured from the aft outboard TE of the wing to the pitot tube and got a perfect 247-5/8″ on each side. It was clearly time to get down to brass tax and get this fuselage mounted while my fuselage-spar alignment was spot on!
As I started the actual attachment process, one thing that I had going on –since I made the spar cutouts on the aft fuselage exactly to the plan’s dimensions– is the foam on the fuselage is higher than the spruce firewall/gear hard point (LWY). I could just fill this area with flox, but I’d rather use a thin piece of spruce as a spacer. I measured the gap at 0.150″.
I grabbed a good piece of scrap spruce and then set up my saw for right around 0.150″ (or ~5/32″).
And made two 5.7″ spacers to go under the spar. I would have preferred 6.5″ long spacers, but this piece of spruce was the best I had available, so I used it.
I then laid up the BID tapes!
My fuselage & CS spar are now officially one assembly!!
I’ll of course wait to layup any glass on the inside longerons until I mount 10-ply BID pads for the engine mount extrusions.
And here it is, the wings mounted to the CS Spar now mounted to the Fuselage! Yes, it’s bit cluttered around the plane, but I’m in the process of building it . . . if ya haven’t heard! ha!
Also, for those folks concerned about me not using a sawhorse up front and relying on that “squishy” front tire to maintain the fuselage level, it did fine. To account for that, I used fast hardener –which let me tell you, is fast!– and worked in phases starting from the bottom spar connect points moving upwards. I also rechecked the level and center measurements a number of times. Hours after I was finished it was still sitting at 0º on the longerons.
I then cut a 1-1/2″ x 1-1/2″ piece of 2024 Aluminum for one of my upper engine mounts. I trimmed it down on the table saw to 1-1/4″ on the leg that will be sticking upright as it is mounted on top of the CS Spar. Just a personal preference to not have such an oversized extrusion mounted in the cockpit area.
[The steps below are technically Chapter 19 and are shown there as well] I then cut the inboard 5/8″ pilot holes on the spar –used for drilling the inboard wing bolt holes– out to 1″ since the edges of the 5/8″ pilot holes were really oily & dirty from all the metal shavings & the spotface pilot rod rubbing against it.
Here are my 3″x3″ pre-pregged 2-ply BID pads, and the 1/4″ foam I used to back fill the holes.
I don’t have any pics yet, but I micro’d in the foam into the holes and then glassed up the 2-ply BID pads over the holes. It was dark and I really couldn’t get any decent pics of this, so I’ll get them tomorrow.
I then set up a heat blanket & a couple of heat lamps on the new layups.
17 September 2016 — Today was a light work day since I’m heading out to Dulles for the annual Airplane Pull & aircraft display. I spent over an hour cleaning up the surrounding area around the airplane (I think I can say that now!).
I wanted to get a pic of what I didn’t last night, and that’s of the inboard holes filled with foam & micro and then glassed over with 2 plies of BID. You can see that this is the initial shot & exactly what I saw when I pulled the heat blanket off for the first time.
Here’s a shot immediately following me pulling all the peel ply. I haven’t cleaned up the layups so it’s all stiff a but rough. I am, however, very happy with the quality of the layups.
Since I found out last night that we may have a chance of thunderstorms this weekend, and I’ll be very much out & about, I decided to really ensure that the tarps were secured well to keep the sun off the raw composite surfaces, and to minimize any moisture… especially in the nose — which I covered with plastic.
18 September 2016 — This evening I wanted to check how the fuselage longeron angles were looking. Since there’s been some fairly significant swings in temps with the weather over the past couple days, I was curious to see if it had affected the front tire at all. It didn’t and the fuselage is still locked at 0°.
19 September 2016 — Today I wanted to temporarily mount the firewall, which required the trimming of the end glass hanging from the layup I did to mount the CS Spar to the fuselage. I marked the glass, as you can see in the pics below, in order to have a reference line while cutting the glass.
I then used the Fein saw to trim up the dead glass. After trimming the glass, I hit the edges with my sanding block.
It was then time to mount the firewall on the fuselage. Uh, just one slight issue. When I marked up the CS spar with the fuselage attached back in 2013, apparently I did it with the firewall off the fuselage. Thus my lines were a hair farther out (say, 0.03″ to 0.04″) than if the firewall had been mounted in place. Doh!
Well, it was fairly tight, but with the help of a “persuader” (rubber mallet) the firewall went back on. Besides my one little spacing SNAFU, everything else with the firewall looks fine!
22 September 2016 — Below shows the final fuselage mockup with the upper cowling. I’m posting these pics on this page since the CS spar is integral to all of this.
Removing wing bolts:
Moving fuselage back into shop:
Tight squeeze, but it all fits!
Side yard is back to normal!
30 September 2016 — Today I finally cut the 1″ x 1″ Chromoly steel engine mount square tube extrusion into 2 “L”-shaped angled pieces. I know some may question exactly why I’m throwing in only one mount of 4130 steel. Well, I was actually going to install two 4130 steel mounts catty-corner from each other, but when the bottom mounts required the use of 3/16″ angled extrusions, I simply decided that between the weight and cost of buying more/thicker 4130 steel, I would punt and simply put only the one top side in. Yes, I considered both top engine mount extrusions being 4130, but now with my engine weighing in heavier, I’m going to employ a little Operational Risk Management here and just go with the one side to keep the weight down, and to keep from having to buy more metal! A little odd? Perhaps. But I’m going to be a little eccentric and go with this!
By the way, after I got it all cut, I matched it up to the engine mount and it was a good match!
[Note: I posted this here since it’s listed in the plans and relates to mounting the spar to the fuselage. However, I also posted this in Chapter 23 since it clearly relates to the engine.]
1 October 2016 — Here’s a pic of today’s work, with the WA16 Spruce engine mount-to-spar-to-longeron wedges at the top and the engine mount extrusions at the bottom right.
Yet another bunch of material I cut but didn’t get any specific pics of are the pieces that will make up the U-channel wing bolt securing bracket (in the middle of the pic above). This will allow me to put the wing bolts in the spar facing out (aft) and be secured against moving. This will greatly facilitate the speed & ease of putting the wings on & off.
3 October 2016 — I started on the engine mount extrusions today by drilling a #12 hole down into the upper left engine mount extrusion’s bottom reinforcement plate. I then countersunk the hole in the outboard 2024 aluminum angle “L” bracket. I didn’t want to drill the other 2 holes on the other side since I wasn’t sure how much compression there would be when the engine mount was actually bolted in place (the plans say 4 AN3 screws according to a CP… but I seriously don’t know where 4 holes would fit for AN3 screws. There technically is 4 screws/bolts going through the extrusion plates into the lower reinforcement plate, IF you count the 1/4″ bolt that holds on the engine mount tube).
I did realize after I Alodined these parts (below) that I had a major brain SNAFU and should have at least drilled & countersunk the screws on the top (long) extrusion. I could then have simply drilled the holes into the lower reinforcement plate later, since it connects both sides… oh, well. No huge deal, just definitely not optimized as for as Alodine coverage.
Now, my main Alodine goal for today was to at least get the Engine Mount Extrusions Alodined. I cleaned all the parts with a quick wipe down of Acetone. Then I cleaned them with a 3M pad and Simple Green, and rinsed them thoroughly. I then took them outside and Alodined them. In addition, I was also actually able to prep & Alodine the Aluminum parts for the wing bolt brackets that will allow me to mount the wing bolts in the spar quasi-permanently facing aft to greatly simplify wing mounting/removal.
You can see below that the 3 aluminum engine mounts and the outboard spar wing bolt brackets are Alodined. Clearly I still need to finalize cleaning up the edges of the 4130 steel engine mount.
4 October 2016 — Today I spent almost 2 hours cutting all the BID required to install the top & bottom engine mount extrusions (4 total) to the CS spar & longerons. Probably not a very exciting pic… but cutting glass for nearly 2 hours isn’t exciting either! ha!
Although towards the bottom of my task list today, I finally got sick of looking at all the peel ply boogers on the CS spar-to-fuselage layups, so I gave it a higher priority! You may have noticed in my blog post yesterday the significant amount of dust & debri in the nose from mounting the canard (which is now gone…the debri, not the canard!)… with all that was going on I simply didn’t have enough time before heading out to Rough River for a good after action cleanup, and am just now getting around to it. I spent well over an hour cleaning up all the layups from mounting the CS spar to the fuselage, and also the inboard holes in the CS spar forward face I filled with foam & glassed. If you remember, I made those holes for drilling the wing bolt holes. I still need to another good hour in ridding the spar (and then later the wings) of all the offending bondo.
5 October 2016 — Today I started off by cutting the upper left 4130 steel engine mount extrusion into 8″ & 1.6″ lengths.
I then trimmed the lower 0.1″ reinforcement plate for a final fit to the upper left engine mount extrusion pieces.
I then drilled the countersunk screw holes in the upper left extrusion mount pieces.
Here’s a shot of the 3/16″ countersunk screws mounted in the upper left extrusion mount pieces.
And all three 3/16″ countersunk screws mounted in the upper left extrusion mount pieces.
I then drilled the countersunk screw holes in the upper right extrusion mount pieces.
Here’s a shot of all three 3/16″ countersunk screws mounted in the upper right extrusion mount pieces.
Below are the 3/16″ countersunk screws & lower reinforcement plates in place on the upper extrusion mount pieces.
6 October 2016 — I started off today working on the engine mount extrusions. I cleaned all my engine mount extrusions with Acetone, and then gave them a final wash in Simple Green. Once dry, I painted just the ~1.6″ tips of the 2024 aluminum extrusions with a high end silver paint that my buddy –who is an auto body guy– let me borrow a while back. I did this to protect the part of the extrusions that are firewall aft (engine compartment) and to simply make them look a little snazzier than the Alodine look.
Wth the 4130 engine mount extrusion, I primed all the individual parts and then hit the last ~1.6″ with that silver paint. Clearly I’m not concerned about the firewall forward areas on any of these, because the top ones will get painted with the cockpit interior, and the bottom ones will be buried away in the hell hole.
I have to say I had a total brain fart and used packing tape on all the aluminum extrusions when I painted them. What do you get for trying to be too snazzy? An hour of using Goo-B-Gone to get baked on tape off your extrusions!! What a waste of time, and a hard learned lesson in finding out what material in the known universe that packing tape actually sticks to!
I then took a few minutes to sand the Spruce WA16 wedges to their final shape and round over the top edges just a hair in prep for glassing these into place. [I then spent a good 45 minutes cleaning all the bondo off the top of the CS spar. I chiseled the bigger chunks away be hand, then sanded the remaining bondo remnants off].
10 October 2016 — You’ll quite often here me refer to the “sins of the past” in regards to the build coming back to haunt me in various ways. Although, there’s an often number of times where a “mistake” turns out to actually be serendipitous in that it’s better for my specific build or better meets my requirements. Case in point is when I cut the GIB seatback Spruce hard point LWX at the plans 35° on my saw, which in reality should have been 55° on my saw for a more acute angle. When I lined everything up on the numbers, this is what created that small 0.15″ gap between the fuselage sidewall foam (underneath the CS spar) and LWY when I was mounting the canard. It also resulted in there being a slight gap betwixt the GIB seat back and the face of the CS spar. No worries though, since I actually want my GIB sitting more upright, and although this is a very minor difference in angles, the seat back is slightly more vertical than before.
Of course now I have a gap I have to contend with. Again, no worries. I just grabbed a long thin scrap piece of Divinycell foam and sanded to shape to fit in the channel between top seat back and the lower face of the CS Spar.
I then whipped up some micro and micro’d it in place.
Then let it cure.
There is actually a secondary gap between the aft side of the foam filler piece and the dip inward of the glass on the bottom edge of the race-track looking hole in the front of the CS Spar. Again, I think this might turn out better since that edge can be a bit of a snake pit just waiting to bite unsuspecting forearms as your leaning forward, a bit off-balance either trying to stuff stuff into the spar for storage, or when holding a wrench while mounting the inboard wing attach bolt. Thus, I will fill in the secondary channel with pour foam and then shape a smooth bull-nose type transition in prep for 2-plies of BID.
11 October 2016 — Here’s the pour foam application on the back seat / spar junction where there was still a slight gap after I embedded a foam wedge/spacer in between the seat back & spar.
And a closeup shot of the pour foam…
I then sanded the entire foamed area and the glass areas that would receive BID tapes.
I then mixed up some epoxy, micro & flox. I micro’d the fresh foam surfaces and then floxed some slightly uneven glass transitions (mainly from previous BID tape layups) towards the corners.
I then laid up three separate 2-ply BID tape segments: 2″ wide x 4″ long in each corner, and 2.25″ wide x 11.5″ long for the center piece. Admittedly, the overlap of the center BID tape was only about 1/4″ over each of the outboard corner BID tapes, but I think that will be fine for this application.
By the time I finished peel plying this layup, the MGS epoxy with fast hardener I was using was getting very tacky. Since the temps outside were dropping to the mid-40’s F, I went ahead and put a couple of heat lamps on the layup. I then cleaned up, brought the wings a motorcycle back into the shop and then uploaded these pics to the site. I then checked the layup well over an hour later and all looked good, so I took one of the heat lamps away & simply left the other one on to keep the layup above ~70° F overnight.
12 October 2016 — Although I only got about 5 hours of sleep today, strange things were afoot in the shop as I slumbered. The last thing I did before going to bed was I checked the GIB seat & CS spar intersection layup, and it looked it great. It was a bit chilly last night so I left a heat lamp on the layup so as not to have to turn on the heat in the garage for a layup that was essentially cured (or so I thought).
Wanting to check out my masterpiece this morning I was of course taken aback when I saw a HUGE delam bubble running down the face of it. Wow! The only thing I can guess is that perhaps the pour foam was still off-gassing just a tad and over the hours it created a bubble. Or maybe I just need to stop my shenanigans of combining heat lamps with fast hardener… might be just a bit too much for these layups to handle. I’m going to try a mini experiment with that and not use heat lamps on fast hardener layups for a while and see if there’s a difference.
Ok, so here’s this hideous monstrosity of a delam . . . Boo! Hiss! Argh!
It was a few hours before I got around to working on it, or even taking these pics and I swear it GREW! Stand back folks, this ain’t your garden variety delam… this here is a Mojamma delam, and it requires extrication! So I marked off the area for surgery.
And cut it out with my Fein saw….
This is what a close view of sheer disgust looks like!
So of course I had to cover it up… with 1-ply of BID of course. That’s after sanding it and floxing the transitions. I also injected a couple of smaller bubbles with pure epoxy off to the left (in the pic) of this delam,..where you may note the vampire bite marks.
Later, I checked the layup on the GIB seat/CS spar. It looked good & quite well cured, so I pulled the peel ply to get a good look.
it honestly looks really good! It may seem like it still has jagged edges and all, but as I’ve said before, that’s the blessing & curse of MGS, you can see everything. So it may still look a bit delam’d, etc. but the new layup is fine.
25 October 2016 — Today, to mount the upper engine extrusions, I started out by lifting the fuselage nose to get the longerons to a level 0°.
Longerons at a level 0°.
I then checked the firewall and it was dialed right in at 90°, perpendicular to the longerons.
I calculated the thickness of the firewall (since I haven’t glassed on all the BID yet) at 0.355″ and simply rounded that up to 0.36″ and added it to the 1.6″ for the part of the engine mount extrusion sticking out aft of the firewall for the engine mount to attach to.
After removing the firewall, I mocked up the engine mount extrusions (remember, the top ones are a mixture of 4130 steel on the left side and 2024 aluminum on the right) and then checked the WA16 Spruce wedge spacers. Since my fuselage is just slightly more curved, I cut the WA16s 0.4″ at their widest point vs the stock 0.3″. This of course turned out to be a wasted effort since even though the fuselage is more football shaped than stock, the plans 0.3″ wide wedge spacer dimension is still the correct size. Ahhh, so I did even more cutting and sanding to get these things thinned down.
I then clamped and set the engine mount into place, only attached to the upper engine mounts for the initial look.
Then came the ENIGMA: I have no idea why, since I thought I was Uber diligent in my measuring of all fuselage dimensions at the beginning of this build, but the face of my firewall is setting at about FS 125.4 vs the plan’s FS 125.0. I have to admit I was remiss in double-checking the firewall dimensions when I installed the CS spar into the fuselage, since I assumed that my spar notches were good due to the fact that I did re-check their measurements. Plus, the firewall fit flush and appeared aligned, which it is . . . just 0.4″ aft where the face of it should be.
The real affect, although over-comeable, is that the top set of engine mount brackets are setting at FS 134.5 vs FS 134.2. 0.3″ may not seem significant, but it certainly is to the W&B when you’re talking about the mounting of the 250+ pound engine, the heaviest component on this entire craft.
My initial concern was that if I simply move the mount closer (which will require some trimming of the upper engine mount stems) that it would negatively effect the clearance of the forward-mounted engine components. But since I’m using Electronic Ignitions in both magneto mounts, they won’t require the forward space that Slick mags do. Thus, if I trim a hair over 0.3″, and mount the engine with it’s normal engine mount stem to firewall spacing, I should be very close to spot on with the FS 134.2 engine mount setting.
[BTW, the measurement below was taken from the face of F28… so, 28 + 106.5 = 134.5].
This shows the gap between the end of the right longeron and the upper right engine mount stem. Note that if the engine mount stem were left at the length in the pic below, it would actually be embedded into the firewall. The aft face of the firewall will be just forward of the double horizontal extrusion plate shown just underneath the engine mount stem.
26 October 2016 — Today marked up the firewall to cut the slots so each engine mount extrusion could transit the firewall.
Here’s a shot with both upper and lower engine mount extrusion slots shown marked for cutting.
I started each extrusion slot by drilling a few 1/8″ holes for the top extrusion slots and 3/16″ holes for the bottom extrusion pass-through slots. I then transitioned to using a saber saw to finish cutting the holes.
After finishing each hole with the saber saw, I then sanded down the pass throughs with 32 grit paper.
Here’s a shot of the firewall mounted with all the engine mount extrusions pass-through slots cut.
Here’s a closer shot of the engine mount extrusions.
I then tested out the engine mount by clamping it in place on the upper engine mount extrusions.
Again, here’s a closeup shot of the upper right extrusion.
My earlier trimming of the top engine mount posts did the trick. Now I can dial in the upper engine mount rings to FS 134.2 as per plans.
I then pulled the firewall off and mocked up just the upper engine mount extrusions before I glassed them in place.
After verifying that the extrusion spacing was good, I then went to town sanding the areas that will get glass during the mounting of the engine mount extrusions.
I then vacuumed up all the sanding dust.
I have to say that this is quite a detailed layup. The time lapse between the pic above and below is over 4 hours. Regardless, here are a couple of shots with the upper engine mounts glassed & floxed into place.
And a shot from the aft side , , ,
I then verified that the left side extrusion’s firewall alignment mark was good, which it wasn’t. So I spent a few minutes tweaking both side, then once I got them straight, I snapped this shot. The line at the top equates to the forward side of the firewall, while the bottom line equates to the aft side of the firewall… Thuss why I paid so much attention to getting these marks aligned properly.
Here’s the right side extrusion firewall alignment mark. Due to the angle of the camera, the extrusion and the spar, it looks a bit off.
But if you look at it from this angle, it’s spot on.
Here’s a final shot of the aft end of the fuselage with the engine mount being used to ensure the upper engine mount extrusions are set in their correct positions.
27 October 2016 — First off, as per plans I let this the engine mount extrusions cure until late afternoon to ensure a complete curing of the layup.
I then cleaned up all the excess glass with the Fein saw and really gave both side layups a good sanding.
One reason I went with 4130 steel on the left side extrusion is that I wanted a higher strength extrusion than stock due to a much heavier and more powerful engine. But I also wanted a low profile extrusion on the left side, since that’s where the passenger enters. I understand it’s back on the spar and out of the way, but I did want no more than an inch high extrusion on the left side.
On the right however, where the canopy is, the extrusion is 1.25″ high. The base leg is even wider at 1.5″ wide. The upper right extrusion is of course 2024 Aluminum. I pretty much left the thick pad of glass that I laid up between the right side extrusion upright and the longeron at the same 1.25″ height as the vertical extrusion leg, but I did taper it down into the longeron surface. Still, the glass under both these upper extrusions is thick, stout & strong!
I then cut the pass through holes on the firewall for the engine mount extrusions. I figured I would have to open up those pass through holes a bit, but it was really tough getting the firewall on. And although I checked the lower longerons to see if anything was messing up the re-mounting of the firewall, I couldn’t see anything.
I opened up the holes based on what I thought was some binding, but I was bamboozled by the firewall in that the real problem was at the bottom, not the top. Since the bottom longerons (or stringers) curve upward, then a bit more needs to be removed from their mounting holes to install the firewall with a straight in motion.
The next issue I encountered was the right engine mount extrusion 1.6″ bottom reinforcement & connecting plate. Since it matches the 1.5″ width of the upper right side extrusion, and due to the slight angle that the extrusion is mounted to the longeron at, I simply just could not get the screws mounted into it because it kept hitting the firewall. Obviously, this clearance issue will only get worse when the Fiberfrax and Stainless steel final cover is added to the firewall.
So I marked a slight angle on the forward side of the 1/8″ reinforcement plate (it’s still attached to the outer angle that the engine mount tube is attached to).
I then trimmed the edge using the Dremel Tool (and a face mask of course!).
I then was able to get the upper engine mount extrusion assemblies installed, and then clamped the engine mount in place.
I then focused on the lower engine mount posts for a bit.
The extrusion pass through holes needed to be modified just a bit, so I marked them up.
I then marked up the upper engine mount extrusions to be drilled in order to receive 1/4″ AN4 bolts. Below is the right side with its drill bit holes marked.
I then did the same for the left side.
And here’s a shot of both sides . . . Ok, ready to drill!
I started drilling the right extrusion first. Of course drilling straight down on these holes doesn’t present any real challenges . . .
But Boy, drilling the side holes sure do! I used a flexible drill shaft that I picked up from Home Depot a while back specifically for this purpose.
I focused on the left side 4130 engine mount extrusion because if anything is going to tear up my drill bits, it will be this hard tough stuff (although its not anything near as bad as stainless steel!)
I rounded up some AN4 bolts and fit-checked the bolt holes. Nice and snug!
It got pretty late, so I needed to stop drilling for the evening, but here’s a shot of both sides with the their one bolt each installed.
Finally, here are a couple pics off the top “ceiling” of the interior CS spar showing the nuts and large washers holding the bolts in the extrusions in place. I am happy that my Spruce hardpoints embedded in the CS spar are in the right spot and that I’m hitting them with my bolts!
28 October 2016 — Today was kind of a slow build day, but I did get a couple of things knocked off the list.
The first thing was I drilled the 1/4″ holes into the vertical leg of the upper right engine mount extrusion & through the longeron.
I then test fitted a couple of AN4 bolts in the holes. Nice & snug and the holes look good.
(The second task I knocked out was finally glassing the front face of the firewall with 1 ply of BID).
29 October 2016 — Today I spent a good 45 minutes looking at the configuration of stuff on my D-Deck area. The 1/2″ square 6061T6 bar that you see will traverse across the fop front side of the CS spar, attached at the front corners of the top engine mount extrusions. Yes, this is a modification of the GIB seatbelt mounts and is NOT per plans. This bar will be mounted with the AN4 1/4″ extrusion bolt on each end (with 2024 inserts inside each of the bar for strength) and also have center mount countersunk screws to keep it secure. That will allow the GIB to simply slide the upper seat belt shoulder straps inboard or outboard for comfort. I weighed all these components, and this modification is within an ounce (probably less) weight-wise as the plans configuration.
The black GIB headrest and components shroud cardboard mockup (that I made in Germany) is a modification I’m doing ala Wayne Blackler (see second below). I like this configuration INFINITELY better than the plans shroud that has the GIB with their essentially in coffin or something…. Blech! With my GIB upper seatbelt bar mod I did have to trim the depth by about 3/4″, but it still looks as if everything I had planned to get mounted inside the headrest will still fit comfortably.
Wayne’s GIB headrest and component housing:
2 November 2016 — Tonight I cut the 1/2″ x 1/2″ square 6061T6 Aluminum tube that I’m using in lieu of the plan’s GIB upper seatbelt mounts. This tube will allow the upper seatbelt straps –with the webbing merely wrapped around it– to slide inboard and outboard to allow the GIB to have a much better variance in adjusting the upper seatbelt straps to their comfort.
I then carried those lines back onto the top of each end of the tube to mark the center point for drilling on each side. I finalized trimming 3/8″ x 3/8″ square 2024T3 inserts, each about 1.25″ long, that slide into place on each end of the tube with the outside face of the inserts close to flush on the each side.
I started with a small drill bit about 1/16″ thick and then stepped my way up until I had a 1/4″ hole drilled down through the seatbelt crosstube ends into the extrusions and then through the Spruce hardpoints embedded in the CS spar, respectively of course.
Here’s a closer shot showing the forward bolt hole on the right extrusion very close to the same spot as my original mark. Up on the longeron is the end of the GIB seatbelt cross tube with the 1/4″ bolt hole drilled through it as well. In this pic you can see the 2024 insert in place (very snugly) in the end of the tube. I’ll remove the inserts and Alodine them before re-inserting them before the final mounting of the seatbelt cross tube.
With the GIB seatbelt cross bar mod and the fact that my longerons are wider in the back than stock, it took me a good 20 minutes to figure out the best length of AN4 bolts to use in all but the aft horizontal bolt position on the extrusions (which is the stock plans size bolt obviously).
Here’s another shot of the bolts that will get mounted into the upper right engine mount extrusion, right longeron, and CS spar hardpoint.
Here’s a shot of the all the upper extrusion mounting hardware. As you can see, I also put the firewall back in place.
I then did a quick check to see how my GIB headrest / component shroud fit & looked (maybe I’ll start calling it something a bit catchier like, “the vault” or something).
It fit fairly well. Of course some minor tweaking will be in order, but so far I’m happy with the configuration back here with the D-Deck and all.
3 November 2016 — Today I worked on the upper engine mount extrusions. I grabbed a 1/2″ drill bit and used it to ream out the glass & foam surrounding the outboard bolt holes in the longerons.
To avoid the same issue that we have when mounting the landing gear extrusions with small washers in subsequently having them embed themselves into the comparatively soft Spruce structures, I decided to use AN970-4 washers on the outboard side of the bolts holding the engine mount extrusions to the longerons.
I started by marking a line the width of an AN970-4 washer over each hole right at the junction of the outboard longeron edge and the attached foam and glass. I used the Fein saw to cut a slot over each hole. I then used a 1/16″ drill bit in a cordless drill to carefully “grind” out the foam to enable me to slide an AN970-4 washer into each slot.
As you can see by the pic below, in standard configuration the AN970-4 washers are too tall and peek out of their slot. I expected this would most likely be the case, so I simply marked each side of the washers and used my Dremel tool to shape them.
Here are the 4 outboard AN970-4 washers shaped to fit into the slots I made on the outboard sides of the longerons (… without poking out).
Here’s a shot of the port-side longeron with the engine mount extrusion holes. You can clearly see the modified AN970-4 washers through the outer 1/2″ holes.
After I got the washer slots made and the AN970-4 washers trimmed to fit, I then moved forward with sealing the bolt holes that I drilled through the Spruce wood hard points. Per the latest CSA and in conversations with Terrry Schubert, apparently over longer periods of time the bolts will actually start corroding due to the moisture in the wood. To remedy this, any bolts placed through wood should have the bolt holes sealed with epoxy first.
I didn’t know about this nor did I do it on the main gear bolts, so I’ll just have to remain vigilant and watch those bolts. But from here on out all bolts & screws mounted through wood will have the wood holes sealed first. As per Terry in the latest CSA newsletter (October 2016), the way to do this is to mix up some epoxy and then simply add just a bit of alcohol to the mix. Apparently this allows the mixture to flow much better and really seep into the wood. The one thing I had forgotten before I reread it tonight is that it takes multiple coats to seal the holes… so no finalizing the extrusion mounting tonight! Again, as per the CSA plans I used a Q-Tip to apply the epoxy/alcohol mix into each hole.
As my first round of epoxy/alcohol mixture was curing inside the wood bolt holes, I went through the process to Alodine the two 2024T3 inserts in each end of the GIB upper seatbelt bar. I first submerged the pieces in Alumaprep for about 3 minutes, giving them a good scrub about half way through. Then I rinsed them thoroughly and set them in place in the Alodine as you can see in the pic below. I let them sit in the Alodine for just over 3 minutes . . .
And then again rinsed them thoroughly with water. I then let them dry out on a paper towel, as you can see below.
Before calling it a night, I applied one more (and final) coat of the epoxy/alcohol mixture to the top engine mount extrusion bolt holes in the Spruce hard points. I’ll let this cure overnight then start tomorrow by actually bolting the upper engine mount extrusions in place.
4 November 2016 — I started off my shop work today by figuring out the exact dimensions & locations of the support spacers for the GIB seatbelt crossbar. The spacers will be a couple of inches from the CS spar CL on each side. Since the right side arm rest and right side horizontal part of the engine mount extrusion are both wider than their left side counterparts, I decided to skew the seatbelt straps over about a quarter of an inch to the left as well.
I marked the spots where the initial holes would be drilled for the eventual installation of AN3 countersunk screws.
I then drilled my marks with a small 1/16″ bit through the square upper seatbelt crossbar tube and into the top of the CS spar, but not all the way through.
I then drilled a series of holes with increasingly bigger sized bits… again, only down until I felt the tip of the drill bit hit the bottom side of the upper inside CS spar skin (on the inside ceiling of the spar).
Once the holes were decent sized, with still a bit more to go for the screws to fit, I stopped drilling for the time being.
And pulled off the seatbelt crossbar to expose the holes. I then spent a good 45 minutes using a scribe to dig out the foam through these holes and shop-vac’ing the chunks out. I essentially created an open cylinder under each hole all the way down to the bottom/inside CS spar skin (remember, I DIDN’T drill all the way through). I would say the resulting air pocket I made for each hole was about .6″ to .8″ in diameter.
I then made up some wet flox with fast hardener and poured it into the air pockets I created under each hole in the CS spar. As you can see, I’m simply making hard points in the CS spar to secure the center GIB seatbelt cross bar screws.
With the leftover flox I then installed the right side modified AN970-4 washers after slathering them with flox. After the washers were in place I installed the AN4 bolts. As you can see in the pic below, I have some trimming to do on the some of each washer peeking out, but overall I’m very pleased with these washers and am very glad I did this mod.
Here’s the flox curing inside the GIB seatbelt crossbar inboard mounting screw holes.
I grabbed a bar of G10 Garolite that I had on hand and sanded down one end so that it was the same thickness as between the top surface of the CS spar and the bottom side of the GIB seatbelt crossbar (approx. 0.2″).
I then flipped it over and marked it to make 2 support spacers for the inboard crossbar screws.
I started by making a center cut that will result in 2 x 0.75″ wide pieces.
I then cut across the G10 to give me the 2 support spacers measuring 0.75″ wide x 0.4″ deep x ~0.2″ thick.
I then set the spacers in place and clamped the GIB seatbelt crossbar over them to secure them in place.
I then drilled a series of holes starting from smaller to larger both through the G10 and also down all the way through the CS spar into each of the hard points.
I then actually drilled the holes out all the way with a #12 bit to accept an AN3 screw.
I drilled countersinks into the freshly drilled crossbar mounting holes and then installed a couple of AN3 screws into the holes. You may also note that the left side bolts are installed securing the engine mount extrusion to the longeron –utilizing the modified AN970-4 wide area washers of course!
It took a bit of fiddling about with the holes to get the screws to slide in without being “motivated,” but I after a good 10 minutes everything was working fine.
Here’s one last shot of the temporarily mounted GIB seatbelt cross bar & the 6 (six) permanently mounted AN4 bolts securing the upper engine mount extrusions to the CS spar and the longerons, respectively.
5 November 2016 — I started out today by gathering up the upper GIB seatbelt straps to modify them to work with my seatbelt cross bar configuration.
I took a big breath and marked the mounting brackets for cutting with my ‘Dremel’ tool.
Here’s a closer shot of my cut marks on the seatbelt brackets.
I then took an even bigger breath and cut the seatbelt mounting brackets at the lines I had marked.
These brackets are some tough metal and I really had to put some oomph into it to pry the cut sides apart to slide out the seatbelt webbing.
Here’s a shot immediately after I removed the seatbelt mounting bracket from the webbing.
And here’s a shot of both upper GIB seatbelt web straps sans mounting brackets.
Now, obviously I had made a decision and planned on going the route of using a crossbar for the GIB upper seatbelt straps, but before I actually glassed in the support spacers, I did want to ensure that the seatbelt straps would work in their “new” (compared to plans) position. Of course everything looked & worked fine.
I put the firewall up & added the “Vault” (headrest & component housing) to get an idea of how it all looks and fits together.
Here’s some closer shots, essentially the same as above.
One thing that I really like about this mod is that it allows the GIB to strap in with the upper seatbelt straps up to 3″+ inboard of the stock plans strap placement. I really do think this will add a lot of comfort for the rear-seater . . . or maybe better stated: won’t add any discomfort from too-wide, off-angle upper seatbelt straps.
With the final hurdle cleared, the mod was a full go! Time to get the support spacers in for good. I 5-min glued the support spacers in place on top of the CS spar.
Here’s are some aft shots of the support spacers 5-min glued in place.
I then whipped up some epoxy & flox using fast hardener. I added a small flox fillet to the forward & aft sides of the seatbelt crossbar support spacers.
Here’s a closeup view of a flox fillet on the support spacer.
I then prepregged a 1-ply piece of scrap BID and laid up one ply on the forward and aft sides of each of the two support spacers. As you can see, I then peel plied the layups.
Again, here’s an aft shot of the 1-ply BID layups on the seatbelt crossbar support spacers’ layups.
A few hours later, with the 1-ply BID layups cured, I cleaned up the GIB seatbelt crossbar support spacer layups.
Below are pics of the cured left support spacer, and then the right, respectively.
And a final shot from the aft side of both seatbelt crossbar support spacers glassed in place.
12 November 2016 — Today I re-drilled the GIB seatbelt crosspiece screw holes, since I had inserted G10 hard points to buttress the square cross tube.
Here’s a closeup shot of the initial drilling of the G10 hard point in the GIB seatbelt crosspiece screw hole.