A Supra with bagged wings, a Luckenbach fuse and a Polecat tailboom

[tonyestep]

This thread is about a scratch-built Supra, but it starts after the flying surfaces are bagged. Jon Stone has a thread going about the bagging process (http://www.rcgroups.com/forums/showthread.php?t=437733) (http://www.rcgroups.com/forums/showthread.php?t=437733%29), and Glauco Lago has promised to do one too. This plane is a co-operative project with Glauco. He’s building one almost like it, but with a Lachowski fuselage. He did the bagging for me, and did a magnificent job on the wings and empennage. They’re all done exactly to the specs as called for in Mark Drela’s plans http://www.charlesriverrc.org/articles/supra/supra.htm

and Glauco hit the target weights specified by Drela – that’s no mean feat, as many who’ve tried it can attest.

To build my plane, I bought a fuse from Terry Luckenbach (terrylasw20@juno.com) and a Supra tailboom from Denny Maize (www.polecataero.com (http://www.polecataero.com/)). The Terry fuse comes with a tailboom that’s a straight cylinder, Mantis style, but I wanted the lighter and skinnier true Supra boom.

Even with bagged wings, a molded fuse and a pre-made boom, there is a ton of work left to do. This build log will follow the assembly of those parts into a finished plane.

[tonyestep]

Glauco and I both got CNC-cut cores from Les Horvath (www.compufoamcore.com) (http://www.compufoamcore.com%29). His work is beautiful, much better than we could have done with templates and a hot-wire cutter. While I was waiting for Glauco to finish the bagging, I made a servo tray and ballast tube arrangement for the fuselage. The tray sits on rails epoxied to the fuse.

[tonyestep]

The ballast tube holds up to 24 ounces of tungsten slugs.

[tonyestep]

I also tried a few schemes for a wing hold-down arrangement. The original plans called for a wing bolt to go right through the ballast slug, and that plane would hold only 16 oz. of ballast. The Supra is designed to be light, but contest experience in our region of the country has shown that planes in the 70 oz. range do best. Therefore, my Supra is going to need a bigger and more convenient ballast system, hence a different wing attachment.
The Luckenbach fuse has a wasp-waist cross-section, so I was able to take advantage of it with the part shown. Note the little slots at the sides near the bottom; the pushrods go through those. Another pic of the part test-fit in the fuse shows them better, with carbon rods stuck through them to check the alignment. Note that the part is tapered, narrower at the front. To get all the compound curves right took some fiddling. I didn’t glue anything yet, because I had to get the wings to be sure everything fit right.

[tonyestep]

The block where the rear wing bolt will go is shown here next to the front block (upside down, before the slots were cut in it).

[tonyestep]

When the bagged parts began to be finished one by one, I started on the wings. Let me say again what a fabulous job Glauco did on this project. The hinges are integral; the flaps, ailerons and rear surface of the wing panels are faced with fiberglass; the alignment of the panels is perfection; the leading edges are excellent, the trailing edges straight and razor-sharp.
The original Supra had RDS linkage for flaps and ailerons, but I have already had one plane with RDS, so I don’t have to do that again. I prefer the Pike arrangement of bottom-hinged surfaces with top horns.
When I cut the servo pockets, I realized that the thin airfoil meant that there was no foam left at the bottom of the pocket, just the bare bottom side of the wing skin. I could have realized this before, but I’m a little slow sometimes.
This called for a change of plans. First, there was no way to use the nice servo frames that I had so carefully machined earlier, because the cutouts would have to be too big. I decided to make the cutouts as small as possible without having to glue in the servos.
Second, I knew I would never be happy with unsupported skin on the wings, so I decided to make a floor of 0.010 carbon for the servo pockets.

[tonyestep]

In the center panel, this still left room for the 368 servos, but in the tip panels, the 368s were now too thick. I had to go to JR 168s instead.
I have heard some bad reports about the 168s, but I looked at the specs, and opened one up and looked at the brass gears, and made the commitment to use them.

[tonyestep]

Then I made wood parts that I could bond to the foam and the carbon floor, so I could screw the servos in place.

[tonyestep]

The best setup I’ve ever used is bottom-hinged surfaces with top horns, and that's what I planned for this Supra.
I made cutouts and horns for the ailerons and flaps.
The linkages are solid and the setup is excellent both for the flaps and the ailerons.

[tonyestep]

To attach the Luckenbach fuse to the Polecat tapered tailboom, you have to figure out a way to make the boom fit the cylindrical opening at the back of the fuse. Here’s the trick.
The boom goes into the fuse 3 ¼”, and over that length, its diameter tapers down by 0.025. What we need is a way to gradually add thickness, zero at first, growing to 0.025 at the 3 ¼” mark. It’s easy; we just wrap the boom with fiberglass.
I had on hand some Sig medium-weight cloth that is 0.0025 thick, so I need exactly 10 layers at the narrower end of the boom. That’s 5 wraps (not 10!). Those 5 wraps have to add zero at the thick end. Since the boom’s diameter at that end is (on average) 0.820”, each wrap has to be 3.14 * 0.82 in length. Five wraps therefore is 12 7/8”. We wind up with a triangular piece of glass as shown:

[tonyestep]

The boom has been wrapped with the triangle of glass, which went around it exactly five times. It looks like a cylinder, and it is; a micrometer shows its diameter to be 0.820 all along the wrapped portion. It now fits exactly into the fuselage, a tight hand fit, no wiggling, no slop.

Before gluing the boom in, I painted the fuse and made provision for a towhook. I machined the hook out of some T-shaped aluminum stock.

[tonyestep]

Next I glued the wing mounts into the fuse.
Note that the wing mounts do not come near the top surface of the pylon. I’ll have to make two more parts to go above the mounts to fill in that gap, because we don’t want empty space under there.
Both mounting blocks have a lot of gluing surface area. The lower front block, which takes most of the load, has about 1 1/2 sq.in. of gluing area. It locks mechanically into the fuse, and there's an upper block with another 1 sq.in. as well. But let's suppose that the lower block takes all the load. If the line tension is 150 lbs. (a full F3J launch), that's 100 psi of shear load. I found a website that rates the shear strength of an epoxy joint at 3700 psi. So even if they're exaggerating by a factor of 10, it ain't gonna bust.

IMPORTANT NOTE: The above analysis is ok for the glue joint, but there could be an issue with the nut eventually tearing through the wood. For more on this, and the solution, see posts 25 - 30.

[tonyestep]

To make a wiring harness like the one shown in the picture above, get the following parts from Mouser (www.mouser.com): (http://www.mouser.com%29:)

571-17946172, 571-17946162, 571-7946113, 571-794613-3

Those part numbers represent male and female connector shells, pins to go in one, and sockets to go in the other. Tom Hoopes uses Molex and these are made by Tyco,but they are identical -- you can plug one into the other. Get a crimp tool from Maxx Products (www.maxxprod.com) (http://www.maxxprod.com%29). Get plenty of extra pins, and maybe a couple of extra shells too, because it’s all too easy to mess something if you have to learn to crimp as you go. There are web pages showing how to do it – here are two:
http://gorobotics.net/index.php?option=com_content&task=view&id=102&Itemid=46
http://www.acroname.com/howto/crimp/crimp.html

[tonyestep]

There's a matching plug coming out of the wing, of course:

[tonyestep]

Note in this picture the black rod-like object running along inside the fuse. That’s one of the carbon tubes through which the .035 wire pushrods run. To install the pushrods, follow this sequence:

Insert the pushrod through the front bulkhead (the one that supports the ballast tube)
Push it back far enough so you can thread a 5" length of carbon tube onto it
Pull it forward until the carbon tube fits between the front bulkhead and the guide hole in the wing hold-down, then feed the pushrod through the hole in the wing hold-down
Put on another piece of carbon tube just long enough to guide the wire back to the slot where it exits the pylon.

[tonyestep]

I made covers for the servo pockets from 0.010 styrene plastic I bought on Ebay (a lifetime supply for 20 bucks). You can use Plastruct from the model railroad store, too; it makes great vacuum-forming material.
I formed the covers over carved balsa molds, using a vacuum-forming machine I bought from a used dental-supply outfit on Ebay.

[tonyestep]

The recommended c.g. is 3.6” behind the leading edge. I had known since the beginning I’d be able to get there without adding nose weight, due to the extra length of the Terry fuselage. In fact, I was worried about the plane being nose-heavy.
To forestall this possibility, I stuck the receiver behind the servo tray. That left a large amount of empty space up front, and I made foam spacers so I could slide the battery back and forth.
Mike Lachowski tipped me off on the right kind of battery to use to avoid having the plane come out nose-heavy: a 1400 mAh NiMH pack from www.cheapbatterypacks.com. Here it is shown in two positions.

[tonyestep]

Here's a pic in the shop when it wasn't quite completed. I'll post a nicer one taken outdoors if the sun ever comes out.

Ya know, I have some other wonderful planes, but there’s something special about this one. Anybody can have a nice molded plane; you put your name on the list, wait for what seems an eternity, pay your money, and put it together. And they are great, no doubt – I have several and I’m sure I’ll have more. But a plane like this is something that few will ever have. It may not fly better, or look as slick, but it is a unique artifact, and when it was all done and I picked it up and admired it, the feeling was pretty incredible.

I said to Glauco, "When I think of all the hours that you put in, and the hours Terry spent making the fuse, and then it took me fifty hours minimum to build it out..."

He just laughed. "That's why not many have them."

[djklein21]

Great work. There is nothing like the feeling of maidening your scratch built work of art.

[Glauco]

Nice work Tony. Can you tell us the RTF weight?

If you don't know Tony is facing a terrible problem. He has three new gliders ready for the maiden flight and doesn't know which one is going to be the first. His beloved one of a kind Supra or the other two everyone has, the Pike Perfect and the Espada RL :D

[nuevo]

with that kind of fleet.... no more excuses. ;)

[tonyestep]

Jon, I'll be ready with plenty of excuses. You know if I had time to build three airplanes that I had time to concoct excuses.

The RTF flying weight is 1491 g, 52.7 oz. The parts Glauco made would have been on track for a sub-50 oz. plane. However, the Terry fuse pod is larger, stronger and heavier than Drela's original pod, and the wood parts I built added weight that wasn't in the original: removable servo tray and rails, bulkheads, etc. Not that the weight matters - the molded ones weigh about 65 oz. and they're still too light. Some guys report using 8 oz of ballast on dead-calm days.

[regis]

Execllent write up - thanks! I have the pod and boom and would like to use them - your log will be most useful. Now please let me where I can get a bagged supra wing. ;) Regis

[nuevo]

I forgot to mention. All the work looks SUPERB. My compliments to the chefs. Best wishes on all 3 planes.

[markStockton]

The block where the rear wing bolt will go is shown here next to the front block (upside down, before the slots were cut in it).

Hi Tony

I have to ask. Isn't the grain of the wood in the main block running the wrong way.

Mark

[tonyestep]

Mark,
The grain of the front block, the one that takes the load, runs vertically, from top to bottom. Therefore the load of the wing bolt pulling on the imbedded nut is taken by the end-grain.

On the rear block, the grain runs from front to back, which is weaker. However, this block takes less load, and there's more wood above the nut, so I can't picture it getting crushed.

[Kiesling]

Tony,

I think what Mark is getting at is that it may be better for the grain to run across the width of the pylon. This will make the block act like a short beam in bending. As you have it you are relying on the shear strength of the wood to hold your wing on.

I quickly looked up some shear strengths of some typical woods (pine, spruce etc.) and they range from 650 to 1100 psi. Eyeballing the dimensions of the front block (without the added piece on top) the shear area between the nut and the top of the block appears to be around 0.5^2 inches (0.5"x0.5"x2). So the shear strength using the non conservative 1100 psi would be 550 lbs. This with the extra piece of wood at first blush would seem to be okay. However, if there is any gap between the wing and the block, the wing bolt will preload the shear joint a certain amount depending on the size of the gap and the amount of torque used on the bolt. This can rapidly reduce your margins. Also with a few dorked landings the wood may split.

So while I expect the mount will work for a given number of launches, it would be prudent to add a few layers of 3 ounce glass on the front and back of the mounting block. The weight penalty will be minimal, but the peace of mind will be priceless.

FWIW
Tom

[tonyestep]

Tom and Mark,
Thanks! Your analysis is very helpful. It'll be easy to add the glass, and I'll do it posthaste. I was focused on the shear strength of the glue joint, but I should have been thinking about the wood too.

[markStockton]

Very well put Tom. I know that my wing mounts on my Supra take a real pounding on landing.

[tonyestep]

To address the point raised by Mark and Tom, I put two layers of 3 oz. glass both on the front and the back of the wing block, extending about 1/2" onto the fuse. This will spread the loads that might tend to tear the nut vertically out of the wood, splitting the grain. Don't omit this step, which takes only a few minutes. After more exchanges of info with Tom, I'm convinced that it's a very wise precaution.

Update: See Post #33 for a simple trick that greatly reduces the load on this joint.

[tonyestep]

Well, today it had its maiden flights. A perfect day for trimming: almost calm, steady non-turbulent lift.

Despite my best efforts to get all the trims set right on the ground, it took a few tries before it wanted to cruise straight and level. It's built nice and straight, and doesn't drift off-line when doing consecutive loops. Tried one roll, which was pretty darn axial. Without ballast it flies darn slow, and I kept trying to get the speed smoothed out even though the wind was only 3-5 mph.

Launches were okay, but I need to practice with it; I couldn't get it nearly as high as I think it can go. I also maidened my Espada RL today, and it launched about 100' higher than the Supra. But I think it's just a matter of working through the setup and the technique on the Supra.

It climbs in the lightest lift, as one would expect. And its handling in the landing approach is really sweet.

I didn't get a full picture of the way it responds to tweaking the trailing edge. It penetrates better with reflex, but at 53 oz. everything is in slow motion -- and positive camber didn't really improve the climb in thermals, slowed it down too much. So that will take some study as well.

I need more days like today to really figure it out. But it shows a lot of promise!

[markStockton]

Well done, it sounds like you have a winner.

[tonyestep]

The wing/fuse attachment takes a lot of stress, not so much from the straight pull on the towline as from torsional stresses on landing. Moreover, sharp rudder control can actually yaw the fuse relative to the wing. This is inherent in the design of the pylon and mount system.

The solution is to transfer more of the loads evenly around the pylon. After some thought, I realized that there's a really easy way to do this.

I bought a 1 mm sheet of rubbery silicone stuff at the grocery store, where it was being sold as a "Garlic Peeler." Two bucks, good deal.

I cut out a wing/pylon pad as shown and stuck it to the wing with 3M77. Presto -- with very little torque on the wing bolts, the wing is many times more secure to the fuse, can't twist, loads spread all around the pylon.

[Phil Barnes]

That is a great tip. In fact it reminds me of Tom Kiesling's original Mantis sailplanes that had pylon mounted wings. He used a piece of tire inner tube for the very same purpose.

[markStockton]

Brilliant and so simple. I will definitely do the same on mine. If I ever finish the molds :eek:

[Kiesling]

The original Mantis also only used one bolt. This allowed the wing to pivot in the event of a not so straight dorked landing. The frictional joint also absorbed energy in the event of a midair etc.

The trick was to have enough frictional force to keep the wing straight under normal operating loads. This was a function of having a good fitting wing saddle and the appropriate amount of torque. As long as you had these things the method worked very well.

If you didn't have the right amount of friction, you would end up flying with a skewed wing. My current Supra has two steel bolts and I just do my best not to screw up my landings and avoid midairs.

Tom

[markStockton]

My current Supra has two steel bolts and I just do my best not to screw up my landings and avoid midairs.

Tom

Have you thought about using a plastic rear bolt that is able to shear during a hard (skew) landing or midair.

Mark

[Kiesling]

Yes,

My second and third evolutions of the Mantis used a nylon rear bolt.

The Supra I currently am flying has a very narrow pylon and only allows for 8-32 (~4 mm) bolts. I don't feel comfortable using a nylon bolt this size.

Since the model is relatively light it can tolerate some abuse. But mostly I do my best to avoid skewed landings and midairs.

Tom

[Jim Frahm]

tonyestep, JonStone, and Glauco,

You all did a great job on the build threads. I just ordered the cores, tail boom and pod based on your recommendations. I don't have any experience bagging wings and was wondering if you could recommend someone who provides this service?

Thanks again for a great build thread,

Jim

[tonyestep]

Whooo. I've heard that inquiry before, and as far as I know, Catch-Air, there is nobody who does custom bagging. Phil Barnes is the gold standard of commercial bagged wing makers, and you should contact him and see what he has to say, but his construction method is different from what is designed into the Supra wing.

The bagging design for the Supra is significantly more complex and difficult than the typical bagged wing. Jon Stone's meticulous thread documents it very well, and there's also a blog by Gerd Nieuwodt that covers some of the same ground.

Phil has perfected a different technique, which you can learn by ordering the instructional DVD:http://www.rcgroups.com/forums/showthread.php?t=190214
The wing he builds on the DVD is done differently than the Supra wing, but you'll learn a lot.
One reason that the Supra wing is so hard to build is that there are many pieces of cloth, some Kevlar and some carbon, that have to be butt-joined, which means they have to be cut to close tolerances and then placed perfectly. The goal is to make the wing and control surfaces strong enough, particularly in torsion, with minimum weight. You can simplify the construction by simply building it somewhat heavier. One way might be to make the spar and fit it into the core as shown on the plans, then add carbon panels, then glass over the whole works with medium bias glass, similar to the layup shown on Phil's DVD. I have a composite Bubble Dancer built that way, and it came out very nicely and has lasted five years and survived hundreds of violent launches. Others may have better suggestions, but the idea would be to simplify the layup so that a first-timer could get it to come out.

A particular hot spot is the hinged surfaces. Jon and Glauco did them the truly-fabulous way with the facing applied before bagging, but it is bitchily hard. You could do them the somewhat easier way shown on the DVD.

Now I don't want to discourage you -- in fact, just the opposite. I think it's cool that you're undertaking this, and it's a rewarding project. I flew mine today, and as I learn the plane I love it more and more. Launches now are on a par with my Pike Perfect, which is to say they are massive, and when the plane hits lift its response is dramatic and thrilling. The Terry fuse is a work of art, and when you mate it to the Polecat boom as shown in this thread, it makes a great setup.

I think the thing to do is just to make a stab, then if you don't like it make another, and keep making stabs until you have the bagging figured out -- then just go on to the other parts, one by one. And be patient. In the best of circumstances it's a one-year undertaking.

Tony

[Jim Frahm]

Baby steps, yah I get it. ;) I'm working on a DLG as we speak. I just picked up the cores from the maker of the Encore, and the pod and boom were made by a fellow club member, so I'm learning a lot about the building process. There are more tips and tricks to laying up glass than any other form of building I've done. :eek:

I've viewed Phil Barnes' DVD several times, and I've read several threads on bagging and molding. I'll continue to monitor build threads, watch the DVD and help/learn from the local guys; the only reason I wanted bagged wings is the time factor.

Thanks again for all your efforts on the thread, I'll post some photos once I'm at that stage.

Jim

[tonyestep]

Yeah, definitely post your photos, that would be cool!

[skyboyken]

Tonyestep,

I'm planning to build myself a Supra by buying fuse and boom and making wings and tails myself. I would really appreciate some pictures and description of the wing joining system in your plane please.

Thanks!

skyboyken

[tonyestep]

Ok, Skyboyken, I'll take pictures of the joiners.
Since everything's buttoned up, there isn't much to see, but I suggest you look at the Supra plans:
http://www.charlesriverrc.org/articles/supra/all%20PDFs/kev_tube.pdf
http://www.charlesriverrc.org/articles/supra/all%20PDFs/joiner_build.pdf
http://www.charlesriverrc.org/articles/supra/all%20PDFs/supra_wing.pdf
The Supra joiners are not explained as clearly in those drawings as they were in the Allegro plans, perhaps because Dr. D assumed that by the time the Supra came along the reader would know how his joiner system works. Therefore I recommend you check out the Allegro joiner:
http://www.charlesriverrc.org/articles/allegrolite2m/joiners.pdf
The Supra does not have as much dihedral angle at the break, hence the joiners are easier to fabricate than for the Allegro.
Finally, be sure to read the very helpful text file from the Allegro plans:
http://www.charlesriverrc.org/articles/allegrolite2m/joiner_build.txt
That should get you going.
Now, with that background, here's the link that REALLY shows you how it's done:
http://www.charlesriverrc.org/articles/bubbledancer/PDFs/joiner_V2.pdf

[Jebera]

Hello all!

Sorry by asking it here but can't find more interested and skilled people out there!
so, the question is:

What woul be the weight penalty if I use the 1.7oz kevlar for all lay-up?
Could I make some lightening holes on the wing tips and tail group and then cover with Oralight? :confused:

Please, sugestions are wellcome cause cant find 1.0oz kevlar in Brazil and it's very expensive. :eek:

Thanks!

André.

[stanradzikowski]

good stuff there :)

im actually in the process of getting some cores cut and bagged for a supra as well.

[markStockton]

What woul be the weight penalty if I use the 1.7oz kevlar for all lay-up?
Could I make some lightening holes on the wing tips and tail group and then cover with Oralight? :confused:


The weight penalty won't be very high. The model with out lightening holes should come out at around 1.8kg (including carbon doublers and reinforcing) which is the same weight as the molded model.

[Jebera]

The weight penalty won't be very high. The model with out lightening holes should come out at around 1.8kg (including carbon doublers and reinforcing) which is the same weight as the molded model.


Very good, thanks Mark! :D

And what about the lightening holes, how much wheigt i could save and what geometry for that holes?

Course I would like to maintain the same structural integrity as the original version.

Thats May be a question for Dr. Drella !:p

Anny other sugestions?

[little flyer]

I got the chance to see Tony's Supra in person and I can say I was very impressed. The finish on the wings was exceptional and almost looked molded. I didnt get to see it in the air but at 52.5 ounces I know I didnt want him in my flight group.

Jeff
PS. Thanks for the calling :)

[tonyestep]

Thanks, Jeff! It was a pleasure meeting you and your dad and watching your outstanding flying. Keep practicing with Karl and Richard and you'll soon be on the WC team.

[tonyestep]

BTW, note above prediction made June 3. Jeff is indeed on the WC team!

[John Walter]

Tony: That was indeed a very good call. The Gateway Open was only his second open class contest yet you predicted the ultimate result like you had seen the movie! :D

[nuevo]

How have the clevises worked out? IMHO, you should go with metal clevises.

A little story... I was flying a Sharon V-tail during F3J at the NATS a few years ago. As soon as the zoom was done, I knew something major was wrong. The plane was, shall we say, difficult to turn. I knew I had pitch control, as I had just completed a zoom. Trying flaps, I knew I had power to the wing. Just no turning. Well it did sort of turn. Kind of like an 145" span Oly 2 with no dihedral, and 3 ounces of lead taped to each wingtip. :rolleyes: I finally gave up, punted the round, and just got the plane safely on the ground. Took a bit of effort just to get it down safely.

It turns out that both plastic aileron clevises gave way. :eek:

[tonyestep]

Yeah, you're absolutely right. I did indeed change to metal clevises after I took these pictures. I had a clevis failure on a different plane and it scared the heck out of me. My story is identical to yours, the ailerons fluttered on launch because of flex in the clevises, and it just ate up both aileron clevises. Got the plane on the ground, went home, and threw away all my plastic clevises.

[Robert Burson]

It turns out that both plastic aileron clevises gave way.

Three years ago, 15mph to 20mph, SOAR OVSS contest, Zoom funny sound, no control of the wing. Semi-controlled landing ( crash ), four disconnected plastic wing clevises. The Pike Superior lived to fly another day, amazing ships. All metal ever since.

I know this will be topped, but it is still fun to be part of the process.


The Best Soaring

Robert

[Glauco]

I was Bob's timer when his clevises exploded. First time timing him and was some of the longer 10 seconds I ever saw. Must say Bob's flights are much longer nowadays.

Funny too because I bought the plane Tony mentions above which had the same kind of failure. When I saw Tony had the plastic clevises I told him a sad story about a guy in Chicago flying his Superior but he didn't believe me...now he does :D

[BrianSmith]

While more costly, I wonder if an Ava fuse and tail would be a good combo for your home built Supra wings. I have a Thermal Dancer wing I just installed on an Ava fuse and tail and I'm just delighted with it. Brian Smith
PS I have put a number of other wings on Ava fuses, and not a bad flyer yet.

[tonyestep]

More on plastic clevises:
I had a scary incident last Saturday with a plastic clevis. It was screwed onto a coupler with at least 1/2" of threads gripping. I made a violent maneuver that put a hard pull on the pushrod, and the threads inside the clevis gave way, causing it to slip about 3/16" on the coupler! Needless to say, I crashed, but fate was with me and the damage was practically zero.
So again, as a reformed sinner, I say: get religion, ye who use plastic clevises. Run right to the shop, unscrew them all, throw them in the trash, and replace with metal.

[StevenatorLTFO]

Here is a strange twist on all of your tales of woe.....

The other morning, I was by my workbench, and I look down, and see half of a metal clevis... the half with the hole.. I have been looking over all my birds, and I can't find where this might have come from! Somewhere I have half of a metal clevis on an airframe, and so far, I have no clue where!!!!!

Steve

[nuevo]

Tony,

I'm confused. Didn't you say in post #54 (March 08) that you threw away all your plastic clevises?

[Mark Miller]

That's what happened to Brendan's Resolution last year. It was very cold out and the stab hit his head on launch and it broke the plastic clevis. No more plastic for me.

Mark Miller

[tonyestep]

"...Didn't you say in post #54 (March 08) that you threw away all your plastic clevises?"
============
Ah yes, but two of the damn things escaped the purge, and that's what bit me Saturday.

[nuevo]

thanks for clearing up my confusion. Glad the plane is completely safe.

[Twizter68]

Finally started on mine; got the stab out of the bag yesterday, came out pretty good, except for fisheyes in the blue paint...oh well!

[gklimber]

Way to go. Finally started on the Supra !! I was just looking at the plans tonight and thinking I may start on mine since I've almost got the OLY 3 done. The thing is, I have all of the composite material for another Genie (SGP) and really should just go ahead and do that one rather than invest in the kevlar etc. needed for the Supra. It's always money.

Cheers, Jer

[tonyestep]

HELL FREEZES OVER!

Glauco's long, long-awaited scratch-built Supra is finished and flying. I hope he'll post pictures here. It is beautiful in its Brazilian blue/yellow paint scheme.

I believe that it's been two and a half years since Glauco and I started scheming about the Supra builds. It took us months just to get the materials together. I drove 100 miles to fetch a gallon of MGS epoxy; he bought a fuse pod from Mike Lachowski at a contest, and I bought one from Terry Luckenbach; he got the .DXF files printed full-size; he made special gizmos to drill the joiners, taper the edges of the mylars, and so forth. It was slow going. Glauco is a meticulous guy, and the last thing was the RDS installation in his wing, which is a slow process for anybody. But now it's done. Let's see some pix, Glauco!

[Glauco]

Here you go

You can see a little report here (http://www.mvsaclub.com/mvsa/Flying_Reports/Entries/2008/6/10_The_Supra_Flies.html)

Took pictures during the whole construction so I just need to find a bit of time to post them.

[nuevo]

Wow!!

[BrianSmith]

WOW !!!! I say it louder !!! :D Nice work friend. Brian

Wow!!

[tonyestep]

Isn't that gorgeous?!

Note that the ailerons do not go to the tips, and the flaps don't meet in the middle. These little modifications are very valuable. Aerodynamically, it's better if you build it according to the design, but in practice, taking the plane from your basement to a hot field changes the trim of these surfaces a little bit, and it may keep changing through the day. I have found it hard to keep the thermal, cruise and reflex settings the way I want them, and would definitely prefer to have the reference provided by the tabs at the tip and center as on Glauco's.