ASW-24 4M Rescue

[mlachow]

There are lots of old sailplanes out there. Unfortunately no all are in flyable condition. This is an old ASW-24 from around Y2K. It had a rough landing that damaged the fuselage, and wing. Some rebuilding was done but it wasn't completed. It took a while to figure out what it was and if it was interesting enough to rebuild. The fuselage has markings from Krause. It is interesting that the decals on the fuselage said ASW-27. The wing was just a double taper ailerons and spoilers. So the best match is ASW-24 which the owner thought it was. The wing damage was all past the spoilers. Fuselage damage wasn't that bad and the joiner was soft enough that it bent The canopy was in good condition. You can't always find replacement canopies for old stuff. So it needs some repairs, some servo replacement, new joiner 12mm joiner rod, and finishing. One thing I did like is for the age, it wasn't some big fat, high cambered airfoil. It looks like an HQ/W 2.5/12 So it should perform fine.

[mlachow]

The wings were a joy to strip to return to kit form. The monokote was old, really old. If you just tried to pull it off, you get clear plastic and all the color and glue remains on the airframe. The old tape hinge and mylar gap seal were pulled off to remove the ailerons. Then a heat gun was used to assist in removing the covering. It was dialed up to around 300F to heat up the old glue. If you warm it up then the covering can be slowly pealed off the wing. If you move too fast and it starts leaving all the junk on the wing. push the plastic back down and heat it up and rub the plastic back into the color/glue. Then resume slowly pealing off the monokote making sure the entire area being pealed is warmed.

This method is not perfect, some color remains. Since the wing is obechi, it was easy to scrape a lot of this stuff off with a single edge razor blade 90 degrees to the surface. It is scraping, not cutting the glue off. If you get the vast majority off the wing, the last bits can be sanded off. Some areas might still have a little bit of grain filled with color but it will be minor.

The bottom of the wings were clean out to the servo area. No visible damage or repairs.


The tip areas showed damage and repairs beyond the servos.



The color was marker used on the area to show when things had been sanded out. Some strips were routed and hard balsa was glued in those areas. Obechi isn't that much different from really hard balsa. The last half meter of the wing isn't that critical for bending strength. Some minor filling was all that was needed to get this area into shape where it would be hard to tell from the undamaged areas.


Here is another bottom repair beyond the aileron servos. This one had some new wood spliced in.

[mlachow]

One wing panel had damage to the top skin at the end of the spoiler. The repairs here were filled with a layers of fiberglass/epoxy to replace the obechi. So far the repair behind the spoiler was removed. This was done with a dremel set up on a router base and some strips clamped to the wing to guide the dremel at the edges. The wing was cut down just to where the foam core starts The edge of the cut was tapered. The filler piece was cut and the end grain edges beveled. A piece of fiberglass was also cut just slightly longer spanwise. First the glass was placed in on the core, then the balsa using laminating epoxy. Really hard 1/16 balsa was used. It stands outside the obechi. After the resin cured, the balsa was first planed and then it was sanded to the proper level even with the obechi. Some covering scraps were applied over it to double check that the wing was smooth in that area..

[mlachow]

At this point it was time to do some testing. The sailplane weighed in the 11lb range. Time to gather up about 10 lbs of tungsten weights to test the wing. The concern was bending from the start of the spoiler out to the tip.



A 12mm rod was put into the root of the wing and a foot of the top foam wing bed was placed on a workbench. The rod was then clamped to the workbench to hold the wing upside down. The wing from the spoiler area out hangs over the edge of the bench.

The test weights were evenly distributed from the tip to just past where the aileron starts. This is still outboard of the spoilers. About 10lbs of weight was placed on the tip. This deflected the wing by about 4 inches. A pretty good test of the repaired areas.

You can do the math on how many g's you need to pull to have 10lbs of force on the outer half of the panel with an 11lb sailplane.

[mlachow]

The wing has a long skinny aileron. It had some JR341 servos on there. Modern technology is so much better. New round mounts were cut to fit in the round holes for MKS HV6150 servos.

[mlachow]

The stab was easy. Just strip the covering.


The fuse shows some cracks in the gel coat at the bottom of the T-tail. The question is it just gel coat damage or is anything more visible inside. The rudder post needed to get pulled anyway since it was partly unglued. The elevator linkage was through a bellcrank. The elevator pushrod was also bent a bit so there was lots of friction.



The post pulled out easily. The bellcrank was nicely mounted to the fuselage on a brass standoff that had some c-clips to retain/remove the bellcrank if needed. Nice setup for the day but now you can get some nice light weight servos and put them in the tail.

Nothing obvious for damage internal to the base of the fin. You can see where the extra layers of cloth are placed in the fin. It is still worth sticking an extra layer of cloth internally. On the outside, the gelcoat will get sanded, and some light fiberglass applied to the outside.

[mlachow]

The wing roots need some work. The old tubes were already removed. Not much glue was used originally. The spoiler servo mount in the fuselage was in the wauy and that was removed.



The fuselage looked pretty good inside but it had some gelcoat cracks along the wing root and canopy frame on one side. There was a surface patch done on the outside by the wing root. This was removed with some heat applied to soften the epoxy. After some sanding to remove the gel coat, some cloth was applied on the outside. A thinner repair to the gelcoat for cosmetic purposes.




The real repair is on the inside. Several layers of fiberglass were cut and fit. The one side just had extra glass near the joiner while the other side had pieces by the joiner, yo above he wing root, and forward past the leading edge and under the canopy opening.

[mlachow]

New joiner tubes have been cut and glued in place. The front end of the fuselage is fine. The tow release operates fine after digging out some dirt in the nose. The canopy is good enough.

[mlachow]

Replacement wing rod tubes have now been added. Time to double check to make sure the wings look good. Visually they look like they match and the meter agrees.

[mlachow]

The base of the fin was sanded to remove the gelcoat that was cracked. One side was obvious. The other side you had to look carefully to see some cracks. Flexing the fin there was no obvious movement. Looking into the fin there were no cracks through on the inside of the fuselage. The gelcoat is pretty thick. The nice part is then putting some light glass on the outside, things will blend in pretty easily. Some heavier satin weave cloth will go inside. The satin weave cloth conforms better to the compound curves.

[Sinkhappens86]

Very cool, I love a good restoration project!

[mlachow]

I also have some smaller sloper rescues. The Zipper one is real simple. They Coyote is really ugly. It has hit a few trees but the fuselage is OK.

[mlachow]

I haven't taken any pictures lately and I've also been putting time into Zipper and Coyote rehabs. The Zipper is all recovered and just needs new control rods, RX install, balancing. The Coyote was pretty beat up but now that is also almost ready to cover.

The ASW24 has a new elevator servo mount. The brass post on the bellcrank was ripped out and a MKS 6150H servo mount was epoxied around that position. A new fin post has been cut. A new spoiler servo mount needs to be cut. The fuselage also has a quick prime and paint in the repaired areas with some rattlecan stuff. The fuselage will get a total repaint after I see how it flies.

New aileron servo mounts for MKS 6150 servos were installed. And the ends of the wires have new connectors installed to replace the 20+ year old connectors. A little more filling surface shaping has been done on a few places to get a nicer airfoil on the wing. The wing is almost ready for a new covering job.

[mlachow]

The wing and stab have been recovered. Some of the old covering that came with the model was too old or stored at some odd temps. If behaved like really old covering where the color peels off the plastic. Fortunately I had some other old rolls that I have had around for a while and those worked well The backing on oracover usually comes off really easily but the bad stuff was a little harder to peel off. At least I'm clearing out the old covering stock.

The repaired areas of the wing have one layer of 1.2 oz fiberglass applied to the outside just. By putting release film (not peel ply) on the glass, you can squege out most of the air and you get a pretty smooth finish.



White on top, red on the bottom with two stripes.

[mlachow]

The ailerons and the elevator have been hinged. Budget technique, 3/4 wide strips of Oracover top and bottom.

Much more work on the tail. The old rudder post and hinge wasn't the prettiest thing so I built a new one. Stripped off all the stuff from the LE of the rudder. Added new tube for the hinge wire and some balsa to cover the gap. Then made a new post for the fin with three wire supports. The TE of the rudder also had some chips missing. It was trimmed straight and a new strip of hard balsa was added.



The elevator is changing from long wire to bellcrank to elevator to just an elevator servo at the base of the fin. The old bellcrank pushrod was pretty heavy and the bellcrank mount was a turned brass piece. The other wire was around 1/16. So some parts weigh less while I added an MKS 6150H to the fin. It should not change the CG that much.

[mlachow]

The tail is now glued up. The clamps were a little stronger than I needed. One of them distorted the fin a little. Alignment done with the laser level. It's not perfect but it looks fine. They all bend in the air anyway.



A new servo mount was installed in the fuselage for the single spoiler servo. Remember when servos were much bigger and less powerful. I changed the ends from clevis to snap on ball links. The old spoiler pushrod is also a cable, not music wire. So the stiffness of the last few inches inside the fuselage depended on solder. I put a piece of brass tubing over most of that to keep it straight.


Pushrod and servo works fine for the elevator. The servo weight is almost the same as the old pushrod and bellcrank. The new pushrod is a scrap piece from some of the lightweight high modulus pushrods from F3b models. Hardly weights much more than the clevis and pushrod end.

Next up is mounting the elevator servo wire and stringing new pull-pull cables for the rudder. Swapping out the ancient rudder and release servos for some older JR metal gear servos sitting around and installing the wing servos. The model is pretty close to a flyable. There is no retract or wheel in there right now.