Genie From the Middle

[gklimber]

Way back in the summer I contributed a bit to another Genie Build thread and then, as often happens, the project got semi side tracked, but I've taken up the tools again and hope to make some progress this winter as long as the fingers stay thawed out.

The fuse and tail are done (pictures are included) and I've taken on the wings. So far I've only split the cores, made the end caps, and cut the CF spar pieces to length. Next is the bolt hard point. We have to "wing it" re the length which doesn't seem critical. I'm thinking I'll make it out of some cherry I have which is easy to get to. There's a big piece of bass in the wood pile, but it just seems too much effort to dig it out -- I know, I know -- sloth.

The front end of the fuse has a piece of paper stuck on it as a first attempt to develop a bit of decoration. I can't claim to be original with that or the color scheme. I saw the colors in Harlie's gallery. I figured I could match white in monocote with the rattle can white easier than trying to match yellows for instance. The original scheme was blue fuse and yellow wings and tail.

When I first took the fuse to the field everyone wanted to know where I got the mold. The thing is glass over wood. ;)

Well, that's a start on this thread. More pix when there's something to show.

Cheers,
jer

[dion9146]

Jer,

Looking forward to the continuation. I'm a builder at heart and just finished up an Allegro Lite, but want to build a Genie as my next big 'build'. That and I need to perfect my soaring skills a bit more so I don't doink the thing. It's too pretty of an airplane to sacrifice to my flying skills right now!

Good luck with the next phase of the build.

Dion

[kablair]

Jer,
How much does your fuse weigh (w/o radio)? I'm in the process of laying up my SGP fuse in a mold I made and would like to know how much less (if at all) it could weigh.

Thanks,
-Keith

[gklimber]

I was afraid to weigh the beast, Keith. But, I took the plunge. The stabs together weigh 1 3/4 oz. (38 gm.). The fuse without the battery and receiver, but with the servos and rudder weighs a massive 1 lb. 10 3/4 oz. (766 gm.). With the receiver and battery pack: 2 lb. 1/2 oz. (932 gm.). I didn't detach the rudder 'cause it is "wired" in place.

I've no idea how this weight stacks up, but it doesn't seem heavy when I hold it in my hand. There's 4 oz. of lead in the nose which Harley recommended. It makes the thing balance pretty close to where it should. I'll tweak the battery location and should be OK balance-wise.

Tonight I finished the wing bolt hard point by laminating it up out of scrap 1/16 ply I had left over from the Spirit Elite. The thickness etc. worked out just like Harley said it would -- funny thing about that. :>) I also got all of the blade boxes made and started to grind the angle in the 1/2" spring steel blades.

I suppose tomorrow I'll get the spar webs made and maybe tomorrow night I can get a start on putting the spar together. It's supposed to rain through the weekend, so I guess it's build rather than fly.

Cheers,
jer

[chrisco]

Jer,
Thanks for sharing your Genie, it looks really good to me. I am getting ready to build the Easy LT/S version. Which Genie version are you building here?

Chris

[gklimber]

It's the Big Genie. Shortly after I started this thread, I realized that I never said which version it is, but then never came back to the idea. Thanks for asking.

jer

[gklimber]

Today I ground the angle into the 1/2" joiners and fit them to the blade boxes. I ground very slowly and frequently dipped the metal in some water so as not to spoil the temper of the steel. I was able to do it all on the wheel and didn't need a file.

I assembled the spar using methods essentially as per Harley. Also as per Harley I made up a jig for "hot rodding" the cores. The actual rodding didn't go as planned. Of course the first section of core went perfectly just to lull me into a false sense of security. It's mate has a slanting hole exiting from it's bottom. I managed to get a pathway cleared, but it's gonna take a little creativity to run the wire -- I think it can be done though. The other pair of panels went the same with another hole in the core bottom. Of course I burnt my finger in the process.

I'm gonna have to seal the slanting holes well so epoxy doesn't leak into the channels and spoil my day later on. The channels in the cores are usable as long as you pass the "fishing" wire in the right direction. I've taken notes for later. :>)

I joined the cores back together and tomorrow I'll wrap the spar and install it between the cores. That's about all I have to report

[gklimber]

Spar wrapping was sort of fun after I got the spar supported at the end and the kevlar thread set up so it unwound under tension from the spool. All I had to do was turn the spar. The center section is all together with the spar in place etc. Now it's on to beveling the end caps and installing the new brass tube/nylon sheer bolt tip joining system. I almost went nuts trying to figure out why the end caps I had in my hand were 3/4" thick when the instructions kept talking about the caps being 1/2" thick. Then I remembered to look at the original version of the instructions and there I found it -- when tape was the only option for tip joining, end caps were 3/4" stock fit between tip and center section, beveled on both sides and split.

Tomorrow, that's how I'll proceed and then we'll fit the new tip joining system to the beveled caps.

Cheers,
jer

[soholingo]

any pictures?

[kablair]

Jer,
How closer are your spar wraps? My last Genie was thread-to-thread for about 60% of the length. Took 4 hours to complete. From the other thread here on making a Supra spar, I was considering using Dr. Drela's suggestion of using glass.

-Keith

[John Lueke]

Hot-rodding the wire tunnels was the scariest part of getting the cores ready, but when I actually got around to doing it using the jig, it was no problem. Moving the rod at the right speed to keep from melting too much foam is the key. The hole comes out larger in diameter where you first plunge it into the core because the rod is at its highest temperature.

[gklimber]

Sure, be glad to post some pictures -- I just assumed that most would be familiar with the appearance of this stuff given Harley's detailed instructions.

The gashes in the bottom of the cores might be of interest from the standpoint of getting some suggestions as to how to best go about fixing them. And then there's the 1/16" misalignment of the front core pieces on the spar and the small shim I added to correct this. Might be educational -- no doubt therapeutic -- confession and all that.

The spar wraps -- I'll post a picture of this, but it's mainly just how it's shown in the "script", but with more wraps. The thread count is pretty dense (right much overlap) at each end of the blade boxes and at each end of the bolt hard point. The rest of it is probably two or three times as dense as shown in the script -- that is out and back on each side with the wraps about 1/8 to 1/16" apart each way. I wrapped the outboard (tip) blade boxes VERY densely with lots of overlap -- pix later.

John, I was at a loss to explain why the rodding setup worked so poorly. Maybe I didn't get lined up well enough to begin with, but it looked ok to me -- somehow the rod was wondering vertically -- OK, it just hit me -- I was using a slightly shorter rod than shown such that I was getting pretty close to the end of the guide board at the end of the pass. The distal end of the rod couldn't have helped but to droop a little even though I had firm contact with the guide board -- leverage etc. -- next time I use a longer rod and have lots of it in contact with the guide board when that 8" mark is reached. I may even install some sort of additional guide hole so the proximal end of the rod can't lift -- such is the price we pay when we are both Scotch and impatient !!!!

Last night -- late -- I started to fool with beveling the end caps -- I'll get on with that today and hopefully post some pix of that and what I did in the past few days. I just thought that pictures of this stuff would be boring to folks who no doubt already knew the details of the build, but I guess not -- at the least they may generate additional interest in this design. It's a beautiful bird and something just about anybody with just a little skill can complete.

more later,
jer

[harleym]

About beveling the endcaps, I initially used 3/4" thick wood and beveled both outer edges with a 10" disk sander I splurged for. This involved a jig to slide on the sander table to bevel each side of the wood 2 degrees. Then the work was divided down the middle to make a pair of endcaps.

Then, a few weeks ago, the light came on how to do the beveling on the bandsaw. The picture of the setup does show a no longer used 3/4" thick endcap I had laying around, but the text in File 3 does now specify using 1/2" thick wood to bevel to 3/8" wide at the bottom edge.

If you go for the tapped pieces of 1/8" aluminum for the "No Tape Tip Attach System", you want to size and position them on 1/2" wood so the blade clears them during the beveling process.

As always, "sticking to the script" is encouraged. I've made enough "uh-oh's" to go around for everybody and eventually have figured out how to avoid them. I've also had the dismal experience of "hot-rodding" tunnels out of the top and bottom of the cores. The setup used and procedures detailed avoid that.

Updated web pages were posted a week ago, but promptly get outmoded if I'm building something and stumble onto something worth incorporating. I wear a path from the workbench to the computer to detail new discoveries.

The surprise ship, performance-wise, of the Genie line is the "Easy LTS". With it's non-bagged, Monokoted, balsa-skinned, foam core wing it flies far better than I expected that it would, even with all the wrinkles in the covering. My film covering skills are amateurish. I used a Teflon coated travel iron, no longer owning a sealing iron with a protective sock. Since that last posting a week ago, I've totally redone File 11 about it and will shortly have friend Jay Decker replace what's in there now.

For you fellows who are not ready to get out of your comfort zones to do a real carbon skinned, bagged wing, the Easy LT/S is a major step forward compared to a sticks and ribs built-up winged ship.

[greyhound flyer]

As you can see with this tool, it has a fairly wide entry tunnel to support the heated rod as it goes through the foam. Some of the things I remember about burning the holes are:

1. Make sure the foam core is held down with lots of weight to not only keep it from moving, but to keep it as straight as possible while burning.
2. Heat the music wire to cherry red and plunge it into the foam immediately.
3. Go at a pace of about 2-3 inches per second, twisting the wire as you go. At first, you should feel absolutely no resistance at all, but it will slow a little as you go.
4. If you start to feel resistance, don't force the wire any further. Pull it out, heat it back up and proceed. Harley recommends not burning more than about 24", iirc...
5. You may need to come in with a boring tool made from sharpened brass tubing to line things up and prevent snags.

This concludes the foam burning tutorial, thank you. My name is Dr. Ruth Westheimer; I'll be here all week, please try the veal... :D

[gklimber]

The pix of the jig are very informative. Looks like the idea of two supports for the wire has already occurred to someone -- i guess aiming is just a matter of sighting down the poker. Red hot -- boy. Part of my problem I think was not knowing exactly how hot I had the thing. I tried to judge this by feeling the rod at the eight inch mark.

Harley, I'm not trying to re-invent the wheel with the end caps. I guess I'm lazy, but I started the wing part of the project using a printout of the script as it existed back when I started -- months ago. After I finished the end caps I found the new updated version and started using it so I found myself having made the 3/4" caps where the new plan specified 1/2" -- I think it will be a simple process to adapt the new fastening system to the 3/4" caps I have and still do the beveling on the band saw.

I have posted a mess of pix. They show the spar from both ends, the shim to correct the front core misalignment (BEFORE TRIMMING TO SIZE), gashes, outboard blade boxes, and the band saw setup. The I'm just using the tilt table on the band saw to get the bevel after several trial cuts in waste stock to set it just right -- I measure it with a large protractor. The wood thing on the band saw table is a magnetic knife holder I use as a fence. It sticks to the table very well as the magnets are strong. These pictures should answer moist of your questions -- if there are more, just ask.

Gotta go.
jer

[greyhound flyer]

Jerry,

I was looking at your overburned holes, and an idea came to mind for how you might fix them with minimal fuss. Get some 3/4 oz or 1.4 oz glass and wet out some pieces large enough to cover the exposed tunnels. Let that glass cure and then sand a slight relief around the overburned areas to accommodate the thickness of the glass--probably about 1/64" or less. You can then attach the glass with a little epoxy or polyurethane glue, and it should not be visible through to the skin.

What I'm not sure of is whether or not that area might cave in under vacuum. You should probably test a sample and see if it works. The thick mylar should prevent it from happening, but it would be a shame to ruin a set of cores experimenting. :)

--Byron.

[gklimber]

Something akin to that idea was bouncing around my brain, but conventional old pink spackling won out. Actually, I might do both. Fortunately, the burnt out gouges don't communicate with the wire carrying passages, so they can be completely filled with something. The glass patch would assure a good seal against intruding bagging epoxy and the spackling would supply some support. Whadayathink ?

jer

[John Lueke]

Just to add a comment to support Harley's praise of the "Easy" LTS. I flew mine in a 2 day contest(man on man) last weekend in Cincinnati. This was only the second contest I have flown in and had a terrrible time launching in the 15 to 20 mph winds. In the third round of the first day, I had a really bad launch and hit my head with the left wingtip. The Genie headed left in knife edge flight about 5 ft off the ground and before I could hit the rudder hard enough or get off the pedal it did a cartwheel on the ground - left tip, then nose then right tip then right horizontal tail. I don't think anyone there thought the Genie would fly anytime soon as they saw it shedding parts. After about an hour and a half at home it was ready to go the next day. No damage to the fuselage, RDS aileron pockets needed to be repaired along with a corner of a flap and some monokote repair to the horizontal tail. The next day, again in 15 to 20 mph winds, but with someone throwing the Genie for me on launch, I advance well beyond my level of incompetence and found myself in 4th place after 4 rounds. So there I was on the line for the last round in the top flight group with my battle damaged wooden wonder surrounded by 2 Icons, 2 Supras and a Fazer. Reality set in when one of the Supra buried everyone in that flight group and I fell back to the middle of the pack. The bottom line is that even the low tech version of the Genie is a good windy weather flyer. It was able to handle full pedal launches in the wind with mild zooms and could get upwind searching for lift.
My last panel for a carbon skin LTS wing came out of the bag Friday, so soon the "Easy" wing will get an upgrade of a layer of 1.4 glass to get rid of the high maintenance non-sticky monokote.

[kablair]

Jer,
If it were me, since these burnt out areas don't connect with wire carrying ones, I'd try to fill the hole with bits of foam and then finish it with spackle.

I couldn't tell, but it looked like it was the top of the wing. If so, and if it's near the spar (where the loads are greatest) then I would be concerned with a potential buckling of the top skin in an area where there's an underlying depression. Depending upon how confident I was of the core repair, I would consider sanding down the nearby area and laying in a piece of spanwise carbon. If it's the bottom, then I'd just put something in to keep it from 'oil-canning' while bagging.

-Keith

[harleym]

Guys. . . on the "hot-rodding" issue, if you read the instructions, you'll see that I'm burning tunnels less than 8" deep in any of the core pieces, not 24" as friend Greyhound Flyer mentioned. I also explain how to align the tunnels to each other in adjacent core pieces.

It's good to see some narrative feedback from others that support my assertions about the ships in the Genie line. Your ideas are welcome. I'm always receptive to suggestions that may make something better or easier to do.

Another modeler I had never heard of or met mentioned grinding opposing flats at 45 degrees on the drive shafts so the setscrews could be easily accessed. However, He had no idea how to do it.That prompted me to create the simple shaft holder detailed in File 6 to use with a bench grinder. This greatly simplified RDS shaft securing in the Kimbrough couplers.

Just today, it dawned one me how to install a very durable slot in the ailerons of the Easy LT/S before the top balsa skin is attached. Details will be in File 11 of the web pages shortly. In fact that entire file has been redone to better support building that inexpensive, but very fine flying bird.

An issue I am still stuck on is pre-installing durable aileron slots in a bagged wing without ruining the cores, interfering with cutting the ailerons loose or beveling the aileron for down deflection. The post-bagging epoxy/CF slot works fine, but I want to simplify fabricating and installing one with a slightly snug fit and that can't split. If I get it figured out, the next problem will be to explain how to do it.

[gklimber]

The gashes are on the bottom and I like the idea of filling them with pieces of foam and epoxy. Might even shape the hole some to make the plug of foam fit better. Can also make it (plug) a little lower than the surface and fill to the surface with spackle which will be easier to sand without messing up the surrounding foam.

When I get to the aileron pockets I'll think on how to do it in the pre-baged phase. If Harley ain't figured it out -- doubt I will, but I'll think on it some.

jer

[jfrickmann]

I suggest you fill out the gashes with some Gorilla glue mixed with a little bit of water. Cover with tape while it dries. I will foam and fill the holes nicely.

[gklimber]

Thanks for the suggestion. I think I would worry about the foaming action being sort of out of control and the foam going up the holes to where they do join the passages where the wire will go. The "gashes" represent channels which branch off of the "real" ones. The wires will pass through but only if inserted from the correct end so that they encounter the Y branch from the top of the Y and coming down the correct arm. The foam entering the other branch may block the junction of the arms and mess things up. That junction is fairly close to the gash. Epoxy and a foam plug is much more controllable. So far it seems the best way to go. Any other ideas out there??

Jer

[jfrickmann]

I suggest you simply plug the main channels with a rod covered by tape whil the Gorilla glue dries.

[harleym]

Well. . .today I got it figured out how to pre-install the hard slot for ailerons in a bagged wing. It will be in File 11. Check the website in a few days.

[tdkamila]

Just tossing a building tip out there.

This worked out well for assembling my fuselage. Cut a piece of wood one and a half inches in thickness to the bottom profile of the fuselage with nose block and a slot for the aluminum skid. Mark centerline ,formers and tow hook location. Locate two pins for the front and rear tow hook holes. Build away.

Tom

[kablair]

Can't wait to see the updated File #11!

Just in time too.... I'll be cutting some new cores soon for my next SGP.

-Keith

[gklimber]

I have a question about the new brass tube / set screw/sheer pin arrangement. Does the nylon set screw penetrate the wall of the brass tube or does it just bear on it?? If it penetrated it would act as a sheer pin if the tube was yanked out the sharp wall would cut thru the screw. If it just bears on the wall like a set screw, the holding power would be less, and the tip would come off easier. An up side to this is that the nylon screw would not get as buggered up as it would if it penetrated the tube wall -- eventually it would loose it's threads. Which way is it -- penetrate or bear ??

I am coming along on the end caps -- pix when there's something to see.

jer

[harleym]

I have a question about the new brass tube / set screw/sheer pin arrangement. Does the nylon set screw penetrate the wall of the brass tube or does it just bear on it?? If it penetrated it would act as a sheer pin if the tube was yanked out the sharp wall would cut thru the screw. If it just bears on the wall like a set screw, the holding power would be less, and the tip would come off easier. An up side to this is that the nylon screw would not get as buggered up as it would if it penetrated the tube wall -- eventually it would loose it's threads. Which way is it -- penetrate or bear ??

I am coming along on the end caps -- pix when there's something to see.

jer

Jer. . .the last 4 lines of that section addresses your question.

[gklimber]

Hi,

I'm on my second set of end caps having thoroughly messed up the first set. It took a while for the design to sink in for some reason. Anyway, since I was fresh out of hard balsa I ripped up some wood I had been told was bass. On section it looks suspiciously like maple, but hey it's fairly light.

I made the new end caps out of this and they look good. I didn't inlay any hardwood blocks, but drilled the 1/4" holes right in the end caps and then inlayed the tapped aluminum pieces along the inboard edge of the center caps. Then, as per the script, I extended the 1/4" holes on into the tip caps, installed the back plates and then drilled the center cap holes and back plates to 17/64" .

I did all of this prior to beveling the caps as per the script. I beveled the caps by setting the table of my band saw to 2 degrees (measured with a protractor against the blade) and sawing such that the bottom edge of the caps came out 3/8" thick. This went fine.

Now, we have the holes drilled square to the non-beveled faces of the caps so that when the tubes are inserted they hold the caps such that they do not take on the angle of the bevel.

It would be better to extend the 1/4" diameter hole through the tip cap AFTER the bevel has been cut so that when the tubes are inserted the caps meet evenly along their beveled edges. The hole in the tip cap would be angled slightly downward -- off of square.

In looking back on it, the only real difference between the script and my method is that Harley tilted the cap against a wedged up board and I tilted the table -- both would give identical results -- the problem is that the holes are being drilled square to the cap faces prior to being beveled.

It'll be no big thing to re-drill the holes in the tip caps, but they will then be a bit big/loose. If they are too loose, I can partially fill the holes with epoxy and then re-drill. Also, I think I have the next size larger tubing and perhaps can redo the holes with it in mind. If all else fails I'll have to do a third set of caps. :(

Jer

[gklimber]

FOLLOWUP

I was able to re-drill thru the tip end caps and with a little fiddling -- the caps fit flush. It's better to do the drilling earlier in the process before the center cap holes are enlarged since the larger holes are a sloppy guide for drilling the tip caps, but all's well that ends well.

jer

[gklimber]

It seems I've been a more active builder than a poster. Here's what has happened since the last post.

The end caps have been glued in place and the section 2 joiner boxes were epoxied in place. I used semi-thick epoxy and filled the space above and below the joiner box. I placed a piece of fairly heavy plastic (from the long bag the tapered spars came in) over the epoxy and taped it down. This gave a nice smooth surface to the epoxy.

I filled the space above the spar with 1/16" balsa set in epoxy. This fits well on the ends of the spar, but stands proud of the surface in the center. It needs sanded down before the spackle is applied. The shallow space over the spar on the bottom surface has been filled with spackle between tape and is drying.

The epoxy over the end caps needed to be roughed up a bit so the spackle would stick. This is drying as well.

The spackle I'm using is by DAP and may not be up to the task. Phil Barns recommends the pink Red Devil stuff. I may have to find some of that. This light weight stuff is more difficult to handle than the regular stuff.

I have taken the leading edge off of the two end section cores on each side and joined both these cores and their beds. The bed for the outer section is thinner than the next section in, but it's a small thing I can glue some 1/16" balsa top the outer bed and they will be even.

Finally, I've plugged/filled the gashes in the bottom of the center section where the hot rod exited too soon. I used epoxy and the pieces from the leading edges. I inserted the foam plugs only as far as needed to keep the surface from collapsing under vacuum. I was able to tell where to stop the plug by feeling the surface over the false tunnel and stoping where the foam felt firm.

Next I plan to sand spackle and foam plugs , cut off the LE of section 2 and the center section, and join section 2 and it's bed to the rest of the tip sections.

Hopefully, I can take some pix some time soon to jazz up this story a bit.

Cheers,
jer

[gklimber]

I know, I know -- I owe you pictures. I just can't find a spot to stop and take them. Currently, I've spackled the spar, the end caps where they join the cores, and too many dings to mention. The DAP spackle seems to work OK -- just takes a while to dry. I have removed the leading edge on the band saw from all of the cores. The next thing is to join Section 2 of the tips to the rest of the tip sections which have already been joined and add the balsa leading edge.

I did a little experimenting with my vacuum pump -- a Gast which I appropriated a few years back from the hospital lab I ran. I've had that pump for years just waiting for a good use to put it to. It has a "variable leak" vacuum adjust and dosen't seem to heat up at all when running. I suppose I could run it continuously, but I think I'll check out using the vacuum switch I bought, an "accumulator" made from some PVC pipe, and a one way valve just to see if I can cut down on the noise. It's not bad, but after a while it sort of bores a hole in your head. It pulls a solid 25 inches of mercury.

Pix soon -- I swear.
jer

[soholingo]

I am still reading...

Jer, when you had the problems with the end cap holes how far did you stray from the script?

[gklimber]

I departed from the script in that I made the end caps out of one piece of hardwood eliminating the need to insert blocks. With regard to the steps involved in drilling and beveling (which is what you are referring to I think) I followed the sequence described in the paragraph following the picture and drawing on page 25 of the newest version of the instructions found on the web page. There is another description ( less detailed ) of the process to be followed after the blocks and aluminum plates are installed on the previous page. I followed the paragraph I did because it was explicit regarding the sequence of events.

Why do I feel like I'm defending myself? I followed the directions to the best of my ability and the result needed correction. It is still better to drill on through the tip block after the blocks are both beveled and not before as instructed.

jer

[gklimber]

Wow -- paranoia seems to have set in last night -- sorry for the curt response.

Tonight the cores and beds got joined together and the trailing edges trimmed. I took off very little -- 1/16" or less. This edge was then sanded down to nothing -- very carefully -- by supporting it on a strip of foam maybe 3/8" thick and sanding with 120 grit.

It seems that the leading edges don't match up chord-wise so I evened them up by sanding the wide one down. It didn't take much -- 1/8" maybe. The leading edge thicknesses were equal when I finished.

The leading edge strips beveled at 25 degreed do indeed fit nicely. It's sort of a judgment call as to just how much of the corner to take off. I guessed right, but don't know how to tell you guys how to judge this. I guess it depends on how close to 1/4" you got when you took off the leading edge. My leading edges seemed to vary some between cores even though the sawing seemed accurate when it was done.

Standing the cores on edge to epoxy the LE in place is a problem with the trailing edge sanded to a fragile nothing. I got around this by sliding the core out of the beds so the LE was exposed by about 1". I then put several long "T" pins through the beds and cores to hold the core in place. I taped the beds together at the ends. They will stand on edge quite nicely and the TE is protected between the beds. The balsa LE can now be epoxied in place and held there with tape strips over the edge of the core. This went quite easily.

I'll include some pictures of all of this soon. It's late and I'm going to bed.

Cheers,
jer

[soholingo]

No need to apologize. When someone strays from the script, I like to know if it was successful or not. I have some ideas I want to try but I am really thinking its better to stick to the script.

[kablair]

The only place I've been successful at deviating from the script is to use a hot wire cutter for the spar slot. And that's only because I can't cut a straight line with a bandsaw.

If you choose to go the hot wire route, make sure to allow for the excess wire kerf.

The other place I've deviated is in making a mold for a composite fuselage. It's okay if you want to learn a new building skill, but I could have built a half dozen fuselages in the time it took me to make one.

-Keith

[gklimber]

This afternoon I got some pix taken and finished the wing joiner retrofit on my Spirit Elite. Now I have 2 semi-winch tolerant planes -- OLY2 with steel joiner and Spirit ditto. But I stray...

I took a picture of the end of one of the tapered LE strips and one showing how it fit to the end cap LE shape so you can see how to cut the angle on the strip. The closeup of the end cap/leading edge combo also shows a closeup of the setup for gluing on the LE. Like I said above the core is advanced out of the beds and pinned there with long T pins through the beds and the cores. The beds are taped together at the ends and then the LE can be epoxied on using tape over the top to hold it while the glue sets. This protects those nice feather edge trailing edges. I'm finding out that they are a pain to have around, but there's nothing for it but to be careful -- very careful. I'll tell you -- I have never been more aware of my every move than when working with these cores.

There are some pix of the end caps that I made out of "hardwood". You can see liberal amounts of spackle covering up my indiscretions and on the bottom view, the tapped aluminum pieced are visible in their notches. I didn't drill thru the wood beneath the tapped holes in the metal. I figure this eliminates one place where epoxy can sneak in and spoil the party during bagging.

The filling over the joiner boxes is visible. This is epoxy thickened with cabosil beneath spackle. The shiny epoxy surface (from plastic applied to allow thickened epoxy to be brought close to completely filling the void) was roughened with a Dremel tool to give the surface some tooth so the thin layer of spackle would adhere. It did. The bottom view of the center tip also shows the repair of the gash in the bottom due to the wayward hot rod. Boy -- I sure hope I can get through the tunnels which are left. On the outside of the cores I have marked the direction in which I need to pass the wire. Now I have to remember to write that down somewhere so I can refer to it after bagging.

That's about it for the slide show. Just respond with anything that needs clarification.

Yes, following the script is necessary. There is a whole lot of information there and as Harley pointed out somewhere, making one change means a whole cascade of changes (such as page numbers) which need to be made. Just keeping that set of instructions current and clear is a huge job. That is why, I suppose, that little things like the description of the sequence for making/beveling the end caps gets included twice and why reading everything multiple times from beginning to end is necessary. Sometimes tidbits of info which are needed at the beginning of a process get mentioned further down the line. I would hate to be the one responsible for keeping that octopus under control and can only say that Harley has done a masterful job of letting us get into his head and see into the bottle where the Genie is born.

Like Harley has said on multiple occasions -- the script is a work in progress and as such isn't perfect. It probably never will be with the number of builders critically thinking over the process and contributing tweeks here and there.

So, we soldier on -- one day the bird will be in the air and it will have all been worthwhile. Thanks, HM.

Cheers,
jer

[gklimber]

Hi,

Since the last post I have plugged the holes in the ends of the caps, applied the over caps, and extended the beds.

I then shaped the leading edges and applied the glass tape to the LE. I also ironed it on. That's a trick I learned after reading the Slow Supra build thread -- lots of good info in there.

I installed the two bits of balsa in the trailing edge where the flaps end. Next time I'll install stuff like this -- where the part must be sanded flush to the foam -- with a softer glue. The epoxy doesn't sand well unless microballoons are added. I suppose something like Gorilla glue would work a bit better.

The cores have been given their last application of spackle and have undergone the steam treatment to remove dents. They are ready to bag. The plan is to bag up the center section first so I have only cut mylars etc. for it.

I cut out the center section mylars and then, with a cabinet scraper, thinned their .014 in. leading edges down to .005 in. over a distance of 3/8". I checked the thickness as I went with a dial caliper. Hopefully this will allow the leading edges of the mylar to conform better to the core and make shaping the leading edges a little easier. This is another trick I learned from the Slow Supra build thread.

Cutting the CF cloth went about as planned. I now have two pieces 60 X 11 inches. The glass cloth required a little thought. It is cut on the bias and the top and bottom pieces must have the same orientation with respect to the warp and fill threads to prevent possible wing warping (according to Dr. Drela). I used waxed paper with a very light coat of 3M as a "carrier" for the glass cloth. In order to get the "carrier" on the correct side of the glass such that the orientation will be correct, the top waxed paper "carrier" was applied to the glass on the bias with the corner of the glass folded over. This means that the "carrier" was actually placed on the bottom of the glass as it was lying on the table. The bottom waxed paper "carrier" was simply applied to the top surface of the glass -- again on the bias -- and parallel to the waxed paper applied above. This results in the waxed paper ending up on the top of the glass as it is put in place on the mylar. It also results in the top and bottom glass having the same orientation. Lots of words. Probably totally confusing.

The plan is to wet the mylar, lay on the glass, remove the waxed paper, lay the carbon on the semi-dry glass and adjust it's position and then wet out the whole thing. The carbon will be "mashed" with a hard roller and paper toweling used to blot up excess epoxy.

I suppose it's possible to slip the layup into the bag for a minute to take out the excess epoxy, but it seems that the layup for this wing shouldn't be super dry.

I've decided on a paint scheme for the thing, but will reveal it when the wing is done.

Well folks, that's about it for now. Lemme know if there are questions or if there's something you would like a picture of.

Cheers,
jer

[Hostage-46]

Good luck Jer... looking forward to seeing how she comes out of the bag.....

[gklimber]

I finally took the plunge today after some hand holding from Harley.

Prior to the big event I worked out a written step by step plan and posted it above the bench. I even had a dress rehearsal with pieces of brown paper for the mylars and core. I'm glad I did both of those things. Also, I built a pair of light boxes -- a coffin with 3 - 100 watt bulbs for incubating the layup during cure, and a small (1 cu.ft.) box with a 40 watt bulb for warming the epoxy in my cold garage. Both were total overkill with respect to the wattages, but dimmers made control possible. I heated the epoxy to 90 F prior to mixing and held the layup at ~90 -- 100 during the evening. I'll probably back off some for over night (~75 F) just because I'll feel better if things aren't too hot while we are asleep.

I also got a pair of "brooder lamps" (which are low power heat lamps) and aimed them at the mylar I was epoxying. They served to keep the epoxy from cooling off too much.

I used E-Z LAM from ASC which has a pot life of 60 minutes. I made two 4.5 oz. batches and used the second batch for the second mylar. The roller (3/16" foam) took up right much epoxy so a second small batch was made up to finish the wetout on the first (bottom) side. There seemed to be plenty of time from the standpoint of the epoxy remaining fluid enough even though I went over the 60 minutes, by then I was on the second batch and had the first mylar in place on the core. It was still plastic enough to flow under vacuum.

I followed Harley's directions pretty much to the letter except I used a piece of brown paper under the mylar and taped it in place -- MISTAKE. I needed to rip it off PDQ to make room for the breather/plastic combo which would have stuck to the epoxy on the paper.

Cutting the excess fabric off around the mylar produced a slight bit of fraying of the CF even though I meticulously removed all wisps of CF from the edge prior to wet out. There were really no other surprises. Be sure to wet out the patch of CF over the extension area on top before the end so you have some epoxy to use. I had to go dumpster diving and rescue some from the mixing cup. What little was left in the mixing cup after that was placed in the coffin with the layup to check on the progress of the epoxy setting up.

The small patch of kevlar for the hinges was placed in the bag between some plastic along side the core. It stuck out of the coffin so I aimed one of the brooder lamps at it to cook it some.

I certainly didn't beat Harley's time of 40 minutes, but considering that everything was plastic when it went under vacuum, it should be OK from that standpoint. It probably took ~80 minutes. The count down timer went off after an hour, but didn't start counting up -- just sat there, so I'm guessing at the 20 extra minutes. I was cutting off the edges of the second mylar when the timer went off -- you figure it out. :D

There are a million things to worry about after it's done -- will the breather batting make a pattern in the epoxy, will the TEs be ok, is it well enough adjusted to the beds etc. etc.

I just have to wait and be patient now. :o More when I know something. Sorry for the lack of pictures, but those of you that have been here know why that is. ;)

Cheers,
jer

[Hostage-46]

Can't wait to see what comes out of the bag!

Wish my ACP stuff would show...:(

[kablair]

jer - as much as you'll want to, and I know just how hard it is, the best thing to do is leave it in the bag for a full 24 hours. I know you've accelerated the cure by adding the heat, but I'd still let it go for the full amount of time.

When you do take it out of the bag, and assuming this is the first time you've done this, remove the mylar from the bottom of the wing first. This way any mistakes in peeling it off will be less visible. I've found that peeling it off in a single smooth motion - like a bandaid, but not as fast - produces the best results. My experinece with peeling it off in a jerky motion can leave lines where the mylar stopped and started.

To pull the mylar off in a smooth single motion, make sure all the edges are free by lifting them away from the core and the inevitable epoxy/fabric mixture that laps over the edge. Once they're free, pick a spot and pull it off - not fast, but continuous.

Let us know how you make out. But, if you can stand it, you'll be better off to not pull the mylars for a day or two after taking it out of the bag. I've NEVER been able to wait, but I thought I'd pass along the sage advice. Assuming you don't wait, handle the panels very carefully as they will be quite susceptible to many kinds of hangar rash for a couple of weeks.

-Keith

[gklimber]

You're right -- first time here. I'll wait a good while before I "look". I've used epoxy a lot in other applications and realize it can take a while to cure. Too much invested in this thing to ruin it in haste.

The advise about the surfaces being tender for a while is well taken too.

Thanks for keeping up with things.
jer

[greyhound flyer]

Jer,

I left mine in the bag at least 24 hrs and maybe even 36. The longer the better, since it will be that much more cured, especially in the hotbox.

As funny as it sounds, you should handle the wing with cotton gloves right out of the bag in case the paint winds up being soft or tacky--you'll leave fingerprints in the paint otherwise. :eek:

Best of luck being patient. It was hard for me to wait it out... :D

--Byron.

[gklimber]

Wait I will. There's nothing more to do until Monday when the order of Mylar gets here from ASC. I figured wrong on the original order and had to get more for the tip panels. Monday I can cut mylars and fabric on the dining room table and still keep suckin' on the bag.

The literature with the epoxy says that it cures over night at room temp. We'll see. I'll let it go longer than seems necessary. It bothers me some to run the pump all that time even though it was designed for continuous operation. Maybe I'll hook up the vac switch I bought with a reservoir so the pump can rest a little.

ciao,
jer

[kablair]

If you bought a vacuum pump rated for continuous duty, then don't worry about it. They use them in hospitals and never turn them off. With a resevoir and switch, you'll just be introducing more complexity and leak sources. That's why I only buy continuous duty rated pumps.

-Keith

[gklimber]

That's where I got it -- in a hospital. It's the kind they used to use to provide suction for chest tubes and the like. It was not being used, so I appropriated it with their blessing. It can be used as a compressor too -- air brush etc. It's just that somehow it bothers me to let it run -- It's just me. I agree on the complexity issue.

jer

[John Lueke]

Not to hijack your thread, but while we are waiting for the wing to come out of the bag, here are a couple of pictures from the beginning. I just finished cutting parts for two Smooth Genie Pro fuselages. My bandsaw doesn't care whether its cutting parts for one or two, so I made two sets. The first picture shows the slab sides being doubled up with carbon. The second shows all of the parts, a fuselage alignment jig, and the all important script. I will finish one fuselage and take the other one to the glassing point. Wing bagging will wait for spring.

[gklimber]

Oh, wow -- you bound yours up in a nice notebook. Mine's just stapled together. I'll bet your shop is really neat too. ;) I am real careful how I take pictures not to include all of the clutter I seem to live in. The "shop" (read end of garage) is small and everything I need seems to be on the work surface at the same time -- it's not where it is -- just how deep.

jer

[gklimber]

PS -- Why are you avoiding the frostbitten joy of Winter bagging??
jer

[John Lueke]

Waiting to bag the wings will give me time to work on the fuselages. I also just got some foam cutting equipment and will be practicing to cut my own cores. I hope I don't need to go through $100 worth of foam to get a set of cores that I could buy for $80. Otherwise, the garage is unheated and we just don't keep the house warm enough to cure epoxy. If I get impatient, I might build a hotbox to cure the wings in.

[gklimber]

OK -- you're excused. :>)
jer

[gklimber]

Well, as usual, there's good and bad.

The good is that the mylars peeled off without a hitch. The leading and trailing edges are sharp and will require minimal labor it looks like. Most of the bumps and imperfections I was worried about don't show and the color is beautiful.

There are minor problems on both surfaces. On the blue bottom, there is this small strange looking whitish area which looks like dust from the spackle. I think it's an area where there may have been a slightly thin area in the paint which is allowing the white overcoat I put over the blue to show through. It's not (too) objectionable and certainly won't affect the flight characteristics. Besides, it's on the bottom. I took your advice, Keith, and did the bottom first. The mylars came off without a hitch. Loosened around the edges and just peeled them off.

On the top of the wing, which is white, there is a vary faint area where there was some bleed through of some black magic marker I had used to mark one side of the mylar. It turns out that I had marked the side in error and went back and removed the marker with a spray parts cleaner. I didn't want to use acetone after having read of some problems someone had with it on mylars. I could not see any residual writing on the mylar, but could see a slight amount of smeared marker. Anyway, you can read "BG top" upside down and backwards right in the middle of the wing top. Elsewhere there is some black residual along the leading edge from the magic marker I used to trace the outline of the wing on the mylar. This is after I thought I had removed it all. This is not objectionable though. In looking back at the mylar, I still can't see any writing. Must all be on the wing now. :>)

I suppose I will have to figure out some cool decal that I can put there in the center of the wing to hide the offending words. I think I've seen some sort of Genie thing on some of Harley's planes.

I guess the moral of the story is to put some masking tape on the mylar and mark on it with ball point or something which will not stick to the mylar. Now I worry about using this mylar again. I think I won't since I sliced through it with a razor blade getting the tape off of the edges -- long story, don't ask.

So -- all in all -- I guess I'm satisfied. Too bad the writing is there or I'd be ecstatic. I guess there's always something to improve on.

There's been enough excitement for the evening -- now for Monday night football. There's no free memory in the camera. I'll have to off load some stuff, but will follow up with some pix of the ghost writing and of the end caps etc. as they are revealed.

Cheers,
jer

[Hostage-46]

Looking forward to pics..... My ACP stuff showed up today :)

[gklimber]

Pix soon. If the "Genie" decal will cover the area I may put it over the bleed thru writing. Failing that, I'll just put my AMA number in 2" letters over the area.

The wing tips should be no problem now that I have been through the process.

I too got some stuff from ACP -- more mylar. This time I unwrapped it and opened the tight roll immediately so the curling I had with the original order should be no problem.

Cheers,
jer

[harleym]

Jer. . .it is good that you got complete paint transfer. I have some nice looking pressure sensitive, black and gold Genie logos that will cover the unwanted lettering. They cost me $4. See near the end of File 3.

When the paint is well cured (many days) put a little auto polishing compound on a rag and see if will take the mark off. It sounds like it would be on the surface of the paint.

[gklimber]

First, the dog is a honey-do which was in the shop so he tried to upstage the picture. You can barely see the ghost writing next to him. The rest of the pix are pretty well self explanatory. There are two pix of the white dusty smudge just to give a sense of scale. Please take special note of the omnipresent script casually thrown in the corner of the mess.

Now it's time to cut the mylars and fabric for the tips. Nice job as it can be done in the nice warm dining room.

Cheers,
jer

[kablair]

Jer -
just beautiful! Those small cosmetic imperfections shouldn't be too visible when you're still going up at 2000' :)

-Keith

[Hostage-46]

Yep have to agree with Keith, I only hope my biggest worry has to do with which decal and where!

[gklimber]

Come to think of it - the reflection on the blue isn't too distorted. ;>)

JER

[gklimber]

Did I mention that I have dyslexia and adult ADD?? Well, finding the main wing bolt hard point under what used to be a pristine top wing surface was an adventure.

Dyslexic me wrote the measurement for the center point of the 1/4" hole in the hard point as 3 5/8" instead of 2 5/8" back from the wing LE. Needless to say, there was nothing in the foam beneath the small hole I put at that point. After locating the spar, I realized that the measurement was off and that what I was hunting was on the forward side of the spar. By then I had a series of pin holes in the skin. Later, when I've returned to my right mind, I'll figure out what to do about the deformities. That Genie logo will have to cover a multitude of sins.

I also finished cleaning up the end caps and sanding the skin back flush with their outboard ends.

I guess I got a little bold, 'cause I also cut the flaps away from the wing. They are reasonably straight considering they were cut freehand. Next time I may consider using a constant chord flap/aileron arrangement. That will allow the use of a fence on the band saw and may produce somewhat better flaps and ailerons.

I have a set of mylars painted for the port wing tip which I probably will get in the bag tomorrow. Maybe I can also paint the other mylars this weekend and get the other tip bagged the first of the week. We'll see. I got a big list of "honeydo" stuff done today, so I'm in the clear for a while. ;)

I'll post again when I have some pix of all this.

Cheers,
jer

[gklimber]

The first of the tips is in the bag. There's a learning curve (55 minutes) but this core is smaller too. I'll give it the usual 48 hours and post some pix Sunday.

Jer

[kablair]

I just put my first tip in the bag today too. It does get faster and faster. I don't think it took me 20 minutes to wet it all out and put it in the bag.

It did take me over an hour to get everything ready :D

-Keith

[soholingo]

Do you mind me posting my Genie EZ/LTS build here? I just cut the slab sides, and could document my fuse build here, which is similar for all the Genies.

Jay

[gklimber]

Gopherit -- this build is lacking the fuse details anyway.

20 minutes huh -- I too took a while to get stuff arranged. That's the key -- that and a handy list of the steps so you don't make a stupid mistake.

This evening I'll be making the masks for painting the mylars for the other tip. I'm using a three color paint scheme. Basically a blue swoop in a red field near the wing tip which is demarcated from the more central white portion by a curved border. This takes two masks -- one for the swoop which goes on first, then a second for the curve which forms the border of the red tip background. The central part of the wing tip is painted white. The colors are painted in the above order.

I experimented in QuickCAD till I liked the look of the swoop and curved border and their position on the wing. I then scaled up the swoop and cut out the printout to make a template. Same with the curved border.

I have pieced together a few large pieces of brown wrapping paper to keep overspray off of the mylar and outlined the carrier on both sides of this paper. I did this twice -- once for each shape to be painted. For the swoop, I cut out an oversize hole where I wanted the swoop to be and then put waxed paper underneath the brown paper so that the hole covered it. I used masking tape for delicate surfaces (purple) to fill in from the edge of the hole onto the waxed paper such that the swoop template would sit completely on the tape and be in the position I wanted. After I cut out the outline, I had a swoop shaped hole bounded by masking tape with its sticky side protected by waxed paper. The curved border was made the same way. It was a simple matter to position the mask on the mylar by feel using the marked outline, remove the waxed paper and stick the mask in place. After painting, the whole thing must be whisked away quickly to get a good border. This is a little exciting given the size of the paper I used, but so far I've been lucky.

To do the opposite tip, turn the masks over and cut away the masking tape. Again, with waxed paper beneath the hole or curve, apply another series of masking tape strips and cut out the pattern from this side. Line up the pattern on the mylar using the outline and you are home free. Just be sure that the outline is the same on both sides -- that is to say that if you could draw the outline once and have the ink print through the paper, this is what you want. It also helps to mark the location of the template on both sides of the paper with pinholes before the enlarged hole is cut out and then make surmarks across the template on both sides so you can locate it in the same place in the cutout area when you turn the pattern over. Trust me on this says the dyslexic with ADD.

I'll take a picture of this and post it with the rest after the tip's out.

Tomorrow we'll see how the whole thing turned out -- and so will you.

Cheers,
jer

[gklimber]

Here are the pix of the masks. I hope the "couldn't wait" didn't get your hopes up for pix of the wing -- It can wait till tomorrow when it's less likely to pick up fingerprints.

I should have just posted these -- would have been quicker for all of us and less reading too.

Cheers,
jer

[gklimber]

The pix below tell the story. The tip looks great. I just took it out of the bag, sanded off the CF whiskers and took the pix. I dolled up the center section some by painting the foam and end caps with acrylic. A word of wisdom here. Make the acrylic just concentrated enough to nicely cover the foam and keep it off of the krylon. If a more concentrated paint is needed for the wood end caps, be very, very careful to keep the acrylic off of the krylon. The less there is to remove with your fingernail the better. I thought the acrylic would chip off cleaner than it did. Fortunately, I have a set of micro-abrasive pads and was able to polish off the stubborn spots of blue paint from the white. It didn't matter as much on the bottom. Incidentally, the micro-abrasive didn't touch the bleed through in the center of the top. Just made the paint there more shiny.

The Pix of the multiple hold down bolt holes tells it all. I think I'll be able to fill the false hole, paint the filled area with a spritz of white sprayed through a small hole in a shield, and then polish the paint patch out with the micro-abrasive. It worked on the fuse where I had to patch a place where I sanded thru the paint.

For now that's all there is to report. Stay tuned though 'cause there might be some excitement when I remove the overcap from the tip. One of the brads I put into the overcap to hold the mylar in place came mighty close to one of the brass tubes which sticks out into the overcap. It came out without too much fuss, so I'm hoping it just grazed the tubing. We'll see.

[Hostage-46]

I'm maintaining my build log here.... finally got up the nerve to cut the spar slot...

http://www.rcgroups.com/forums/showthread.php?t=787996#post8758751

[gklimber]

Good luck Dan. I'm sure we all will be following along if not in fact at least in spirit.

I'll be out of town for the next week -- Christmas in Louisville, KY. When I get back, I'll tackle the overcaps of the tip with those sticky-out tubes, get on with painting the last set of mylars and delve into the mysteries of the RDS.

Till then, have a wonderful Holiday.

Cheers,
jer

[Hostage-46]

Guys I can't get Kevlar thread. I did get some 1/8" Kevlar ribbon that I guess I can use for the blade boxes.

How about spectra fishing line from the sporting goods section? ACP does not have it.

Dan in Dallas....

[John Lueke]

I had an interesting flight today that says something about the Genie's flying qualities. A few of us got together today to fly. It was a gray overcast day in the mid-thirties in Ohio. I launched my EZ LTS on the winch and may have overdone the zoom a bit. On the downward flap of the wings that happens on Genies, the monokote/tape hinge job on the left aileron ripped from one end to the other. I hit the dual rate switches to get as much aileron and rudder as I could. I am happy to report that the Genie was still in the air and handling fine five minutes after the aileron reached the ground. I usually figure it is too cold to fly when the tape won't stick well enough to hold the wingtips on. I will have to check tape hinges in the future.

[kablair]

Dan - Try these folks http://www.thethreadexchange.com/miva/merchant.mv?Screen=CTGY&Store_Code=TTE&Category_Code=KEVINFO
This is where I bought the thread for my Genie.


-Keith

[kablair]

John,
Sounds almost as good as what happened to me at the San Antonio contest this year. I bent one of the wing joiner blades about 30 degrees during an aggressive zoom. Obviously that means I lost control of the aileron (but didn't lose it off the wing), but still managed to get an 8:30ish flight.

My next Genie (about 70% complete) is being built with the .050" blade instead of the .042" one....

-Keith

[Hostage-46]

Guys I could use help on a decision, what type blade box should I go with?

Straight blades or ground blades?

Seems like grinding them will weaken them, any comments?

[John Lueke]

I used the .050 blades ground to the dihedral angle. I just liked the idea of building a length of wing joiner box and cutting it the lengths that I need, but it does take time to grind and smooth the blades.

[gklimber]

Hey guys,

I liked the survival tales -- sounds like this is a tough bird and a forgiving one,

I used the ground blades. I liked the idea of having "heavy metal" there and also the fact that the blade boxes could just be rectangular and not ground off at an angle with the blade. Shaping the blades was quick and easy on a bench grinder. Just go slow and quench the blade often in some water to keep from ruining the temper of the metal. Marking the metal with a scribe (thin line) makes grinding to an accurate fit easier. I held it with a pair of regular pliers or by the tips. A good support near the wheel is essential.

I got a spool of the Kevlar (aramid) thread from CST -- item K902 -- 400 yards. It's the only thing I bought from them. I'm surprised they don't have it.

Yesterday I painted the last set of mylars and as luck would have it, it was an adventure. I've been aware that we have to get the masking off of the paint before it sets up too much and we have to pull the mask in the correct direction to avoid smearing. The swoop went well, but when I went to remove the mask for the curved margin of the red background, I pulled the mask toward the painted area rather than away from it. A large sheet of the paint stuck to the masking tape, detached from the mylar and flopped over onto the painted surface. It also stuck to the edges of the masking tape. I shouted the "F" word, scratched off the excess paint to get a clean edge on the mylar and got the paint off of the masking tape as best I could. I was able to re-stick the mask and paint in the void. There is a slight ridge between the old and new paint, there was one tiny area where the paint didn't scratch off of the mylar cleanly and the white that I put on as a backing for the colors looks like it may have dissolved a little of the new red paint. It looks OK through the mylar and I'm gonna chance it. Maybe if I didn't have a cold and had more energy, I'd be more inclined to strip the mylar and start over. The only fear I have is that the tiny area where the paint didn't scratch off cleanly will stick when I peel the mylar. I'm hoping that the new paint applied over the stuck paint will adhere and it'll all peel OK.

I'm not sure what the best way to take the paint off of the mylar would be anyway. Seems there should be some way of peeling it off?? Acetone seems messy.

I recently bought more CF cloth, so I can do it right on the next one -- a SGP. :>)

Hope you all had a good Christmas (or Holiday as the case may be).

Cheers,
jer

[kablair]

It was surprisingly easy to grind the blades so it's worthwhile going with the thicker ones. I also liked building a straight box instead of having to angle it.

Deja Vu! I had to scrape the paint off my mylar since I used two different brands and they interacted unpleasantly.

It was surprisingly easy - using a credit card (my favorite epoxy spreader), simply scrape the paint off the mylar. Actually, any relatively thick and straight piece of nylon or mylar would work as well. There will still be some residual streaks - use some acetone to clean the whole thing off and then rewax.

I did all that and forgot to cover one of the panels while spraying the other. Now I have a nice red overspray on one of my yellow wing tips.... oh well.



Kevlar thread at the threadexchange.com - about 50 different sizes and styles for very low cost.

-Keith

[gklimber]

Kieth,

You make removing the paint sound so simple that I suppose I'll have to do it. I'll have to make new masks though -- both of the old ones have been used twice and are getting thick with paint not to mention being wadded up in the trash. They didn't take long and I still have the master templates. Lord knows I have plenty of paint.

Maybe tomorrow. Achoo !!!
jer

[soholingo]

Keith,

What size/type thread did you order and how much did it cost?

Jay

[kablair]

jer,
It was depressingly easy and fast to remove all that paint. It took less than 5 minutes once I figured out how to hold my scraper just right. I did find that the credit card would gum up on an edge and it wasn't worth trying to get it clean enough for another pass. Simply use another edge (the shorter edges worked best since they didn't bow as much) and then get another card.

I was also surprised just how much paint I had put on. One tip panel had at least 25 grams of dried paint. That means I could be putting on 4-5 ounces of weight just due to paint. NEXT time I'm putting on thinner coats of paint - so what if the weave shows through a bit.

-Keith

[kablair]

Jay,
Here's the pictures of my roll of thread. I've already used about 400 feet off of it and you can see how much is left. This spool cost $18 including shipping. It is cheaper because it's right twist; which as you'll read on their information page make a difference to weavers but probably not to 'spar wrappers'.

I should have put a ruler next to it for some scale, but it's about as tall as a beer can.

Good product, nice people, great deal, and a wealth of information about kevlar.

-Keith

[gklimber]

$18 ?? That beats the heck out of CST -- theirs cost almost as much and the spool was LITTLE.
jer

[gklimber]

I took the plunge and scraped the paint off. Glad I did. There were a few areas where I had to deal with some minor fish-eyes which turned out a little thin. They would have shown through.

The paint came off cleanly. I used a small rectangular sample piece of formica. I have a bunch of them and they come in handy just as credit cards do. The paint came off in large sheets in some areas - that's how I was able to see the thin spots.

It's raining today, so I'll just make the masks and wait for better weather. Plenty to do on the other wing sections, but I have to admit, I'm no bundle of energy.

Sniff. Snort. Sneeze......
jer

[kablair]

Jer,
If you haven't gotten to it yet, I found a 'fix' for a problem I had on my last Genie.

I made an improvement in the "HEMS" servo holders. On my last Genie, I found that the glue joint between the 1/16" ply and the rail could break when the brass strap was screwed in. Since the only thing holding these together is the glue, I decided to drill a hole through the rail and the plywood through with I inserted a wood dowel. Now there is a mechanical connection and the wood won't interfere with whereever I decide to screw in the brass strap.


Hope you're making good progress. Mine's going a bit slow since my wife has wanted me to go play golf with here this weekend. Oh well, when it's 75-80 in January, you kind of have to go out and play...
-Keith

[gklimber]

Thanks for checking Keith. Thanks for the tip -- better is always good.

Over the weekend I re-did the tip paint job and bagged up the starboard tip. It came out great -- flawless -- sort of. There are two trouble spots.

In judging where to put the mask for the curved junction of the red and white paint, I made small errors on both sides. The curved junction is not at the same place on each tip. I was using the break in the line of the leading edge to position the mask and since it's a gradual curve, it doesn't give a very accurate location to guide on. Since the tips are well separated, there won't be a problem -- next time I key on the end of the tip mylar.

As I was setting up for the bagging I re-read the section in the instructions and noted that the patch over the tip blade box goes on with the CF tows running CHORDWISE. I had made all of the patches at one time and they were all with the tows running SPANWISE. I fixed the problem on the starboard tip, but the port one is wrong.

Harley says that he built a plane like that once (see, he really has made all of the possible errors :>) ) and it flew fine if care was taken on launches in the wind etc. He also said that I could take the paint off of the tip in the area of the bottom patch and vac bag another one over the first one. I think I can do that and use a small mylar to paint the area. It'll be on the bottom -- a good thing.

I can scrape the paint off with my cabinet scraper in an area about 3/4" larger than the patch, then feather the edge of the paint-free area with acetone so the new paint will blend well at the edges. I can remove the wax on the surface at the edges with micromesh cloth so the paint will stick there, then put a new patch on, cover it with F-glass and a dry layup. A mylar will stick to the area with minimal ooze of epoxy at the edges. Then I'll smooth up any unevenness in the paint surface with micromesh after the bagging is done. This should be minimal especially if I fade the paint at the edges on the mylar.

Before I do all of this -- does anybody vote to just LEAVE IT ALONE ???

Cheers,
jer

[gklimber]

PS --

Keith -- did you bag the tips with the brass tubes in the end caps and sticking out into the over caps ??? If so, how'd you even up the end of the skin to match the endcaps ?? The instructions say to leave the brass in the tips and plug the openings etc. I suppose I'll use a jewler's saw to take the end of the skin off close to the end cap -- avoiding it's edge and the tubes -- and then take the skin down to the end cap with a small file.

Has anyone else dealt with this ??

Jer

[John Lueke]

Patch the patch! With all of the fibers running spanwise, there is nothing to spread the load of the joiner box to adjacent fibers except the outer layer of cloth. This may not be enough unless you want to launch conservatively.

[gklimber]

Yea John, that's what I was thinking, but I just needed a little push.

jer

[kablair]

Jer - sorry I didn't get back to you sooner...

I sort of forgot to put in the brass tubes so, by default, this one will have to be joined with tape.

I, too, would want the fibers oriented chordwise. I managed to bent a blade on launch and not affect the wing at all.

-Keith

[gklimber]

Well, the chords have it. I bagged up the patch just a bit ago. The pix show the cleaned area where the patch and f-glass covering will go as well as the carrier with the patch and f-glass in place before wet-out. I used the marks to locate where the fabric should go -- drew the outline of the carrier on the towel and then matched up the corners of the bare area. As usual with this thing -- it's all upside down and backwards. I took pains to smooth the wing tip edges so that they wouldn't puncture the bag. There's less risk of this using the breather/drop cloth method ala Barnes.

I had to make more epoxy up than needed to get an accurate measure of the 2:1 ratio -- 6 drams total -- drams -- sounds like alchemy -- but they were the handy units to use on the little dispo medicine cups I filched from somewhere.

I used a piece of foam roller about 3/4" wide on a small holder for the wet-out -- didn't take a lot to wet the roller. I then used the hard roller and paper towel to blot up the excess epoxy. I carried the epoxy right to the edge of the carrier at the end and along the leading edge nearest the patch. I went out far enough on the other two sides that I was beyond the area I had de-waxed with 250 grit paper, but not to the edge of the carrier. The theory here is that the epoxy will adhere right to the edge of the carrier on the end and the leading edge, but will hopefully "peter out" in a feathered edge before it gets to the other two edges of the carrier. After bagging I can start the separation of the carrier at the corner where the end and leading edge join. This way I will peel the carrier toward the petered out (hopefully feathered) edge. The paint will have less of a tendency to separate from the substrate this way. I suppose the paint-epoxy bond is tight enough that this is not a concern, but better safe than sorry. Hopefully, all I will have at the edge is a fine raised edge of paint which I can level out and polish with micro-mesh pads.

What I don't know is how well the carrier stayed in position on the wing. I didn't want to risk taping it in place and having the tape lift the paint on the top after having been in the bag for 48 hours. There's no carrier protecting the painted surface over the wing away from the small patch carrier. I worry a little about the mottled pattern of the breather fabric getting pressed into the painted surface. I lowered the vacuum some -- to 19 inches of water -- on account of this.

We shall see.

Here are the pix.

[gklimber]

PS -- I think the mottled stringy white appearance of the bare patch area is due to the white paint I put on the mylar "over" the blue to give a deeper color. The white paint is in little dips in the glass cloth between the CF tows. At first I was worried that this was the result of epoxy voids in a too dry layup, but that's not the case.

jer

[gklimber]

Well, as usual there's good news and slightly less good news -- none really BAD.

The paint color was not an exact match or the lack of a white backing coat had an effect. Not a horrible problem -- just wish I could have used some white (it would have shown) or had been able to tell which almost empty can of paint was THE one so at least the lots would have matched.

Next there's a small bubble under the paint at the edge of the patch. Probably not worth messing with unless/until it pops. Then it'll be spackle, sand paint and micro-mesh.

The breather/ground cloth had a tiny film of epoxy on it in some spots which stuck loosely to the painted surface away from the patched area. This flicks off with a fingernail, and will be no problem, but the breather/ground cloth did permit the surface to become slightly roughened. This happened because there was no mylar over most of the wing to spread the pressure of the vac bag which tended to press the surface into any tiny pattern of irregularity which was beneath it even though I used reduced vacuum. Thus, the CF tow pattern is slightly visible where it was not before. In retrospect this could have been avoided by just reusing the whole original mylar and just spraying paint on the end over the patch -- it would have worked fine -- duhh. The top surface mylar could then have been put in place and the two taped together. In this way, the mylars would have kept the surface clean from the epoxy on the breather layer, at the same time spread the vac pressure so the underlying pattern wouldn't have shown through, and kept the patch properly positioned.

It'll be fine -- it's the usual thing where only the (hypercritical) builder sees the flaws -- everybody else has to study a while. I keep having to remind myself that this is my first exposure to this method of building a plane. That's what learning curves are all about.

I'll just take the "good" wing tip to show-and-tell at the club meeting Wednesday night. Mum's the word.

Now it's time to dig out the overcaps, sand back the skins to the end caps, true up the trailing edges, shape the tips and cut out the ailerons.

Cheers,
jer

[Twizter68]

Jer, bring it out next Saturday...I may have something that'll clean it up sweet!

Bill

[gklimber]

I like sweet. I'll throw it all in the truck. By then it may look like a wing -- sorta.

I dug out the overcaps this evening and taking the skin down level with them was no problem. I used a fine jewler's saw to saw around the periphery of the skin and then just went at the remaining overcap with a pointy tool (scribe). There was some epoxy around the brass tubes, but it popped off from the waxed surface. Likewise, the balsa plugs came out of the tubes and blade slots without a problem. I used the sanding blocks to take the skin back level with the end cap. The maple caps made a firm surface to sand to -- CF skin is softer than maple. When I fit the tips to the center section there is a 0.5 to 1.0 mm. gap on the top surface at the joint and NO gap on the bottom -- wouldn't you know it -- the neat work is on the bottom. If the gap offends me too much a strip of white tape will fix it. The gap is smaller than that on a molded Supra I saw today, so I'm not too unhappy.

I have started to even up the TE to match the center section on each side. There's a mysterious difference between sides in the amount of TE which must be removed. Rather than take away something which can't be replaced, I'm taking a break to scratch my head and measure.

To get a straight TE, I glued some 1" sanding belt material too the edge of my 4 ft. level. The wing part sitting in the lower half of the foam bed puts the TE in the middle of the sand paper. The level is kept square to the TE because it sits on the bench top -- it's an easy matter to slide the level back and forth while putting pressure at various places along the wing to keep the sanding action even.

As soon as I get the TE's even I'll cut out the ailerons -- always a sweaty proposition since it's a freehand job on the band saw. Maybe that's good reason to use a constant chord for the flaps and ailerons. ??? Too late for that -- I'll just take the plunge.

Cheers,
jer

[kablair]

I have started to even up the TE to match the center section on each side. There's a mysterious difference between sides in the amount of TE which must be removed. Rather than take away something which can't be replaced, I'm taking a break to scratch my head and measure.

To get a straight TE, I glued some 1" sanding belt material too the edge of my 4 ft. level. The wing part sitting in the lower half of the foam bed puts the TE in the middle of the sand paper. The level is kept square to the TE because it sits on the bench top -- it's an easy matter to slide the level back and forth while putting pressure at various places along the wing to keep the sanding action even.




Don't be surprised if there's a different amount of TE to remove. This just means the mylar carriers shifted more on one than it did on the other - they both shifted some!

I took a cue from Phil Barnes video. I was able to buy a piece of damaged formica from my local big box building supply and made a 7' straight edge. I also made a piece for tracing out the flaps and ailerons. Worked very well.

No sweat on cutting those parts loose freehand on the bandsaw. It only took me about 90 minutes to make those 4 cuts :eek: They came out pretty good and only had to do a minor amount of sanding.


-Keith

[gklimber]

How'd you hold yer breath for 90 minutes ?? The straight edges are a good idea. Somewhere I have/had an 8 ft. one I made from some plywood a long time ago for a 34 ft. boat I was/am building. I'll have to look in the corners of the "shop".
Funny, last night I was thinking about how to get the whole TE straight and even with the 4 ft. sander. that may/may not be possible.

Too many indecisive slashes in this post.

/jer

[harleym]

QUOTE (No sweat on cutting those parts loose freehand on the bandsaw. It only took me about 90 minutes to make those 4 cuts :eek: They came out pretty good and only had to do a minor amount of sanding.) QUOTE

90 minutes?????? Did you have the band saw turned on? About 5 minutes a freehand cut is about what it takes.

No. . .don't make the ailerons constant chord. . .way overkill for turn authority with absence of servo mass and stuff in the tip sections. Looks like heck too when not tapered.

HarleyM

[kablair]

QUOTE (No sweat on cutting those parts loose freehand on the bandsaw. It only took me about 90 minutes to make those 4 cuts :eek: They came out pretty good and only had to do a minor amount of sanding.) QUOTE

90 minutes?????? Did you have the band saw turned on? About 5 minutes a freehand cut is about what it takes.

No. . .don't make the ailerons constant chord. . .way overkill for turn authority with absence of servo mass and stuff in the tip sections. Looks like heck too when not tapered.

HarleyM

I told you guys that I can't cut a straight line with a bandsaw... that's why I use the hot wire to cut the spar slot and the hole for the servo wires.

-Keith