DAW 1-26 HLG Page
If you got here from the main RC_Sailplanes page, you will find information about selecting the 1-26 HLG for a thermal plane and for a slope plane on the Choosing Your First Glider page.
I built a 1-26 HLG to use at the slope. Take a look at my DAW 1-26 Pictures page.
Here are some links for the 1-26 HLG:
http://www.davesaircraftworks.com/ Manufacturer's site -- info on plane,
Foamie Construction Tips, links, etc. Price $59.95 + $6.00 S/H in Cont.
U.S. (CA Residents add $4.50 sales tax) (prices as of 2/2001)
Excellent customer support :-)
http://www.hobbybarn.com/gliders_sailplanes_slope.htm Price: $52.99 + $?.?? s/h
http://members.home.net/cliff/daw126.htm Cliff Schwinger's pictures
Eric Shanon's page Story of Eric's experience with this glider in Kentucky and Guatemala, including pictures.
Skyfishers A fun club that flies this glider and others. Includes some excellent pictures of several different 1-26 HLGs.
Fred's 1-26 Fred Guilfoyle's 1-26 page, includes construction pictures
DAW 1-26 HLG Shopping List -- What you need to get started
DAW 1-26 Pictures
1-26 HLG Construction Tips
First, be sure to look at the Foamie Construction Tips at http://www.davesaircraftworks.com/ . Next, here are several Schweizer 1-26 HLG Construction tips generously contributed by Robert Steinhaus in answer to people's questions on rec.models.rc.soaring:
Robert Steinhaus wrote:
The Schweizer 1-26 HLG is one of the nicest sport slope gliders available. I like it especially with ailerons and with reduced dihedral (2 degrees) straight wings (no polyhedral for the slope). You can build in the 2 degrees dihedral when joining the wing panels by laying one of the wing panels flat against a flat surface while propping the wing tip of the other panel up 2" with a small block. I would not recommend building the wing totally flat as a little dihedral (2 degrees) is valuable to improve spiral stability and recovery. It is easier to use mini/micro servos (HS-81 or HS-85 or equivalent) in this glider. Metal gear servos are better as wing servos (HS-85MG or HS-81MG). If you plan to fly the aircraft on the slope I would install a rudder and rudder servo even though the glider can be flown nicely without it (ailerons and elevator only). The additional servo helps balance the aircraft at the correct CG (Schweizer tends to build up tail heavy so effort should be made to mount the battery and servos as far forward as possible) and rudder adds to the aerobatic qualities of the glider and allows you to practice making coordinated turns (rudder/ailerons) which will serve you in good stead in the future with more advanced gliders. Starting at the manufacturer's suggested CG is fine (you will generally have to add a little nose weight around 4 oz.). Some pilots move the CG back 1/4" or so as they become more advanced. The rearward CG makes the glider more neutrally stable and more aerobatic but I would start with the standard manufacturer's suggested CG initially (Don't skip checking the CG and getting it in the right range however). Substituting balsa tail surfaces tends to make the airplane fly better (if you select light balsa it also helps with the intrinsic tendency of the airplane to build up tail heavy). If you choose to keep the coroplast tail pieces (which are more rugged) you can straighten and stiffen the horizontal stab by inserting bamboo barbecue skewers in a coroplast channel in the middle of the surface. I like polyethylene hinge tape for hinging the ailerons. One source for good hinge tape is CR aircraft (their phone number is 760-451-0056). A roll of 15 yards (enough for quite a few aircraft) is $3.99. I would tend to apply 2" width strap tape span wise to the leading edge even though this was not suggested in at least the early versions of the instructions from Dave's Aircraft Works. The strap tape on the leading edge will help reduce crash damage and is worth the small amount of weight for the slope. Make effort to not warp the fuselage when strap taping it. The bottom of the fuse (from the rear wing saddle to the tail) should lay flat on a flat surface after you have applied the strap tape. The decalage (angular difference between the wing and tail) should be around 1.5 degrees. This is difficult to measure (building the fuse straight so the rear of the fuse lays flat on a flat surface should get you close enough). A Schweizer 1-26 set up for slope can be optimized at an even slightly smaller decalage angle than this for maximum speed and penetration (the factory decalage is more optimum for thermal gliding). Slight bending of the rear of the fuse while heating with an iron or heat gun will help you make small adjustments to the pitch trim. It is surprising how much difference getting the decalage optimized can make to the flight of the Schweizer (especially on the slope).
> Actually instructions say 5.5" of dihedral plus 3.25" of polyhedral for the polyhedral setup, 3.5" dihedral for
> aileron setup. They say the dihedral will relax 1/2" on either setup, leaving you with 5" or 3".
> I assume you still recommend further reduction to 2", right?
Robert Steinhaus wrote:
That is correct David. I find 2 degrees (2" on one tip) of dihedral is about right for an aerobatic aileron style 1-26. EPP does flex under airloads even with the strap tape caps over the spars. Dynamic configuration does actually alter very slightly from 2 degrees but nothing to worry about. If your 1-26 is primarily for the slope I would also recommend strap taping the sub trailing edge of the wing (along with the 2" wide tape around the leading edge and the 2" wide tape on top and bottom of spar). If the wing is going to snap it often tends to break near the root of the wing at approximately the location where the aileron starts near the root. Strap taping the trailing edge helps to strengthen and distribute crash stress near the trailing edge of the wing. I actually like to add a little wood reinforcement right behind the sub trailing edge near the location of the end of the fixed trailing edge and the beginning of the aileron (if you end up with a little extra sub trailing edge [1/8th" x 1/4" spruce approximately] you can glue a 6" piece of this behind the stress point at the root fixed trailing edge to aileron transition as a reinforcement). You have to remove a small sliver of foam to glue the reinforcement in. It is actually useful to angle the ends of the reinforcement a something like 30 degrees (not just chop at 90 degrees) to try to distribute the stress at this point (the joint will bend a little rather than just snapping off under stress). This is in the way of a refinement and not strictly necessary (just my funny way of doing it). [See DAW 1-26 Pictures for detail picture of this reinforcement]
> Could anyone who has built a Schweizer 1-26 (not 2M), suggest optimal
> Hitec compatible servos - aileron model, I cut slots to fit GWS S3002
> STD and they are too wide for the fuselage (always find out once its
> been cut). Also the instructions don't say much about fitting the servo
> in the wing. This is my first aileron model, so can't go on past
Robert Steinhaus wrote:
The Hitec HS-81MG or HS-85MG metal gear servos are what I would suggest for wing servos. Even these small mini servos do not fit that easily in the Schweizer 1-26 HLG (these servos are approximately .5" thick and the Schweizer wing is barely thick enough to accept these servos). You will probably need to install the wing servos closer to the root (where the wing is thickest) even though it is desirable from a aileron linkage stiffness standpoint to drive the aileron from a position closer to the middle of the aileron. Choose a spot for the wing servo pocket that is as far out toward the wing tip as practical but still thick enough to accommodate the .5" thick HS-81MG or HS-85MG servos. Use the servo arms (cut off all of the arms but one) instead of the servo wheels for wing servo installation. I have also used Cirrus CS-21BB servos as wing servos for gliders of this size. These servos have nylon gears and are thinner (about .4" thick) and easier to get into the wing but can not take the day in day out beating wing servos must put up with without breaking gears and having to be removed from the wing frequently. I tend to wrap mini wing servos like HS-85MG in masking tape and then Household Goop the servo into a pocket in the bottom surface of the wing. The pocket for the servo can be burned out with the tip of a hot soldering iron a little easier than cutting the foam with a knife (guide the tip of the hot soldering iron with the edge of a metal straight edge and you will get a smoother pocket). You will have to probably cut the wing servo pocket all the way through the foam (you will be able to look through the wing) although it is nicer if you can leave about 1/8th inch of foam on the wing top surface to help maintain a better representation of the airfoil shape. Goop the wing servo into slots cut in the foam for the servo and servo ears and try to get some glue on the sides and bottom of the servo. Use a piece of white 3x5 inch card to cover the openings on the top and bottom of the wings and tape the card in place with a little strap tape. Leave only a slot large enough for the half servo arm to stick out of the bottom surface of the wing. It is considerably easier to install mini servos like the Hitec HS-85BB (nylon gear) into the fuse of the Schweizer than standard servos like the HS-3002. If you are stuck with the HS-3002 try to mount them as far forwards as possible (the airplane typically builds up tail heavy). The Schweizer fuse is taller than it is wide. I believe the width of the Schweizer fuse will accommodate the thickness of an HS-3002 oriented vertically (1/2 servo arm on top of servo pointing out the side of the fuse). You want to match the minimum dimension of the servo (width) with the minimum dimension of the fuse (width). It is unfortunately hard to get two standard size servos like the HS-3002 into the fuse for both rudder and elevator. It is practical to get two mini sized servos like the HS-85BB into the fuse (and that is my first recommendation if you have the money). The glider is a little nicer with rudder/elevator/ailerons for aerobatics but will fly fine just ailerons/elevator.
Robert Steinhaus wrote:
The Schweizer 1-26 HLG is a super versatile and rather aerobatic slope glider. It is a relatively average hand launch glider (the Schweizer 1-26 HLG wing loading is just to high with normal radio equipment to be competitive as a true hand launch glider and its sink rate is too high). Being EPP the glider is very durable and will fly under a very wide range of slope lift conditions (when you go out flying with a Schweizer 1-26 you will almost always be able to fly and fly well whether you are experiencing ultra light "Gentle Lady" style lift or quite strong coastal storm lift). When built with reduced dihedral of around 2~3 degrees the glider is quite agile and aerobatic (I prefer the aerobatic handling qualities of the glider at a dihedral of about 2 degrees but a slightly higher 3 degrees of dihedral might be preferred by those who are more interested in gentle sport flying and less interested in aerobatics as the aircraft is slightly more roll axis and spin stable). Dihedral is typically introduced into a wing by laying one half of the wing on a flat surface and propping the tip of the other half of the wing up by some fixed amount. To introduce a 2 degree dihedral into the Schweizer 1-26 HLG wing you need to prop one wingtip up 2". A wing with 0 degrees of dihedral would be flat. A wing with 2 degrees of dihedral exhibits 2 degrees of elevation to each half of the wing (if you consider the included angle of the top surface of the wing a wing having two degrees of dihedral has an included angle of 176 degrees). To get the best performance out the Schweizer 1-26 HLG I would suggest building it carefully somewhat on the light side and this means using a pair of mini metal gear servos for the wing aileron servos (like a pair of Hitec HS-81MG or HS-85MG servos) and nylon mini servos (like Hitec HS81BB or HS85BB servos) for the elevator and rudder servos in the fuselage. Most important from a weight standpoint is a good lightweight battery pack since it dominates the weight of your airborne package. I recommend the Cermark 4KR600AE flat pack (about US$12+$3.50 for the connector for your radio system). This battery fits in the nose of the Schweizer 1-26 HLG and is 2/3rd the weight of a standard 500 mah flat pack yet has more capacity (Cermark phone order number is 800-704-6229). The larger Schweizer 1-26 (2 meter) glider is a better match to standard size servos and 500 mah flat packs (you will still benefit from metal gear mini size servos as wing servos like the HS-85MG even on this larger glider).
The Schweizer 1-26 HLG is a fine slope flyer (especially in the aileron version with reduced dihedral of 2 degrees). I feel everyone who slope flies should have a sport glider like it that will allow you to have real fun under almost all lift conditions.
It was clear to me that Robert knew what he was talking about, but it is also
clear that Dave Sanders of Dave's Aircraft Works knows his stuff, so I wondered
why the suggestions on amount of dihedral were different. I asked Dave
Sanders the following question:
Robert Steinhaus, one of the big proponents of the 1-26 HLG on the rec.models.rc.soaring newsgroup, suggests reducing the dihedral to 2 degrees (wing tip elevated 2" when other wing flat on table) on the aileron version for sloping. He seems to be very knowledgeable about sailplane design in general and many of your planes as well. I was just curious what your opinion is of reducing the dihedral to 2 degrees on the aileron version. Obviously you know what you are doing and know your planes better than anyone.
That's fine - go ahead and do it. He's trying to de-couple the yaw and roll axes with that change which is good for aerobatics. His suggestion is perfectly okay.
> I will be mostly thermaling with the 1-26. I would like to get on the
> slope a little, although I haven't found a good site around Chicago
> yet (I'm sure there are some sites).
> Am I nuts to build this as a 4-channel aileron plane? I feel pretty
> confident about my flying and learning abilities in terms of flying
> with ailerons, but will this hamper the planes ability to thermal?
> Is there a big diference in thermal performance between polyhedral and
> dihedral planes?
Robert Steinhaus wrote:
If you mostly thermal fly you can still utilize the full aileron/elevator/rudder configuration to good advantage. Most large competition thermal soarers have this configuration. The best dihedral/polyhedral may be a little more a matter of discussion. Reduced dihedral (~2 to 3 degrees) works out wonderfully on the slope and is more aerobatic. It is quite possible to thermal soar well in this configuration (but it takes a little more effort to keep the wings level especially when soaring at a great distance). The factory recommended dihedral/polyhedral produces a very stable configuration for thermal flying that may be slightly more comfortable for you if you are a beginner since it improves the airplane's roll axis stability. The glider built with the factory wing dihedral/polyhedral has excess stability for a pilot who enjoys aerobatics (as a pilot you always end up fighting the built in self stabilizing characteristics of the model). The reduced dihedral glider has just as good soaring efficiency but you have to expend slightly more effort holding the wings level when flying it.
Jeff Reid wrote:
It's just a weight issue, 4 servo setup will be heavier than 2 servos. A polyhedral setup with roll and pitch stability will be easier to fly and therefore easier to thermal, but this is a flying skill issue, not a glider issue.
And lastly a few notes from David:
When purchasing your covering, keep in mind that there are different weights of Ultracote/Oracover (two different names for the exact same product). The transparent colors (called "Lite" by some vendors) weigh less than the opaque colors. The opaque colors are more durable and many people think they look better on EPP than the transparent colors do. It is a trade-off, and I can't tell you which is the best option -- the EPP is durable either way, and it is nice to have less weight, but it is also nice not to have to repair the covering very often. I went with opaque red and yellow for my Highlander (see the Highlander Pictures page) and plan to use opaque white and red for my 1-26 HLG. As for color schemes, follow the links at the top of this page to see pictures of a variety of color schemes, ranging from simple to really sharp.
Unless you are concerned about the color scheme, I strongly suggest not covering the coroplast -- just leave it white. This will reduce tail weight, thus reducing nose weight and lightening your plane. Also, you can't heat the covering over coroplast, and trying to stick covering to coroplast with Super-77 and no heat is a really frustrating process. Another note, be sure to spray the foam LIGHTLY with Super-77 and let it dry at least 10 minutes before covering - the Super-77 sticks to the foam well, then the heated covering sticks to the fully dried Super-77. It doesn't stick so well to wet Super-77.
In addition to implementing most of Robert's suggested modifications such as reduced dihedral and tape on the leading edge, I decided to make the horizontal stabilizer bolt-on rather than gluing it on. I also did not glue in the aileron wing. What the manual says about it being nearly impossible to remove the wing with aileron linkages in place is true; however, all I have to do is remove the two screws holding the control horn to one aileron, leaving it free to swing around to remove the z-bend from the servo horn, and then push the servo horn around to where it does not stick out of the slot. Now I can remove the wing, remove the horizontal stabilizer, and the whole thing fits in a flat box I can carry on to an airplane when I travel!! See DAW 1-26 HLG mods if you want details on how I accomplished the modification to have a bolt-on horizontal stabilizer. [See DAW 1-26 Pictures for picture of this modification] I also added a tow hook.
I used the Cermark 4N-350-AAC battery pack (4 Sanyo cells, flat pack, 350 mah, same size as a 270 mah pack), a Hitec 555 receiver, and four HS-85MG metal gear servos. I put everything way forward in the nose (see DAW 1-26 Pictures) and used lighter aileron control rods, and it balanced perfectly with no additional weight, much to my delight. Total weight is 19.25 ounces. If you build the polyhedral version for thermal flying, you will have two less servos, no hinge tape, no aileron control horns and push rods, and thus it should weigh less.
To add a tow hook: Take a piece of hard wood about
1" long by 1/2" wide (about 1/8" thick). Good hard plywood
in this size is ideal, or you can use some really hard wood trim or something,
which is what I did. Trace your piece of wood on the bottom of your fuse
where the center of the 1" wood is about 1/4" in front of your Center
of Gravity (C/G) location (see the plans for your plane). Now cut a plug
out of the bottom of the fuse that is the same size as the piece of wood but
about 5/16" deep. Glue the wood into the hole, then use the plug you
cut out (or a piece of scrap foam if you used a dremmel to cut out the plug) to
fill the hole, and trim to match the fuse. Once the plane is covered,
drill a starter hole through your covering, foam and the wood 1/4" in front
of the C/G. Be sure the drill bit is smaller than the tow hook threads.
Then thread in your tow hook. I used a No. 14 X 13/16 screwhook (steel,
not brass, and I would call it an eye-hook rather than a screw-hook, but
whatever). I straightened out the bend at the top of the eye, and it has
worked perfectly. Easy to remove/reinstall.
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