|Available From:||ICARE Sailplanes|
Fullscale glider buffs will tell you the ASW28 is something special. Eastern Sailplane's site boasts "The ASW-28 is Schleicher's new high performance glider for the FAI-Standard Class. This glider incorporates the very latest technology, both in wing section and boundary layer control, and uses the most advanced carbon, aramid and plyethylene fibers in construction. The ASW-28 will be type certified for cloud flying and semi-aerobatics.". For more information, visit:
In the model glider world, in my opinion, to have a successful scale sailplane design, the requirements are to have the right balance between weight, airfoil, proper dimensions (main wing to elevator distances/size) and most importantly the construction. I have heard many positive experiences about Let Model sailplanes, mostly from individuals that fly 1:3 scale models. It came to my attention that Let was offering a smaller model 1:6 scale ASW 28 3m. I figured that if a lot of guys were quite happy with their larger models, perhaps their 1:6 size may also be a good design for a scale sailplane in the 3m class.
The kit arrived well packaged, and most importantly, unbroken -- as one would expect from ICARE. The quality of the kit is exactly what one would expect from Let Model with ONLY one exception -- the ASW 28 is a 3 meter, not a 6 meter model. Let Model’s focus is mostly around manufacturing 1:3.75 to 1:3 scale models and although the ASW 28 3 meter model is 1:6 scale, the quality has not been compromised. It possesses the same high quality craftsmanship and finish as their larger models.
The kit came with:
The cockpit has a scale finish with microphone/levers, seat belt harness, instrument panel and a folded up map in the side pocket of the cockpit.
The control surfaces are:
I'm not going to go into much detail about the assembly of the model. However, I will mention some of the "install" frustrations that I found.
From an assembling and disassembling perspective the model is easily transportable. Each wing is about 1.45 meters and the fuselage is 1.09 meters long.
I recall cutting a plastic horn from an HS 50 servo and gluing it to the elevator (I drilled out a slit with a Dremmel tool and slid it through the "obechi" to the underside of the oracover - top covering). It is important that the plastic piece is glued well to the elevator. The control linkage coming out of the fuselage is bent 90 degrees and slides through the glued plastic horn. This way I was able to get maximum deflection downwards.
The wings are quite skinny, so I decided to utilize JRDS168 on the ailerons. The digitals may be an overkill, however, I don't have to worry about the servo integrity.
I decided to go with the HS 50 servos for spoilers. In my opinion, the servos provide enough torque, therefore, I had no issue using them. There may be some argument/discussion around "servo integrity (HS 50's on spoilers)"; however, I have had 50+ flights with this model and I have not had any issues (knock on wood).
Have a look at the pictures below for details of the install. There are many ways one can move around and position the electronics and wires within the fuselage. I found the best way to place my electronics as illustrated below.
Balancing: I did not have to place any lead in the nose to balance this model. I positioned NiCd 4xSanyoAA1100mAh batteries in such way to achieve the desired balance. This is the first time that I did not have to utilize any "lead" in a scale model - very impressive indeed!
CG: 45 mm (smack in the middle of the wing rod)
In a nutshell, regardless of the flying facility, the ASW was a joy to fly.
Performing loops, rolls and upside down flying is what I would consider normal (for this model) in terms of "aerobatics", and she does it well, as seen on the video.
As far as inverted, I would suggest that be done with a bit more velocity, thus, the model is recoverable to level flight with minimal vertical height loss (when rolling from upside down to level fight). I do find the requirement to compensate mildly with down elevator when inverted; however, I would consider the compensation normal for a model that weighs 1.5 kg's at a comfortable CG for glider flight.
There is slight ballooning on spoiler application - there is only very "mild" elevator down required - I usually compensate manually. I do find the correlation that larger models do not need as much "elevator" correction for ballooning (i.e. 4m scale models) I have about 5% mixed in (elevator down) (linear with no delay at maximum spoiler deploy).
This model does very well on the slope. It has good speed range, excellent penetration and surprisingly, good energy retention for a model that only weighs 1.5 kg's. The responsiveness of the model is superb. Mechanically, the control surfaces are designed well, the fuselage is a good design (with a great(!) paint job), and the wings are strong and have a nice flex to them.
If one is flying slower with marginal lift it is important to get the model on speed when making a turn -the model is very forgiving on slope with low velocity turns. During straight flight the model is able to fly quite slow.
Tip stall of the model is quite predictable; however, when it does tip stall it is important to have enough height or speed to recover - nothing new here for more experienced scale model flyers.
Landing on a slope is not an issue. The key is to plan your approach and slow down the model by utilizing spoilers and the elevator to achieve the desired speed and height. In order to be safe with a low velocity landing, when slowing down the model ensure that the wings are level - hold a straight course until the model lands.
Individuals that are both slope and thermal flyers will tell you that the two "disciplines", if you will, are not entirely compatible. Behavior of a model on a slope and flat field (thermal flying) is quite different. This difference in "behavior" of a model is more unique when it comes to scale gliders.
I would definitely say that slope flying is much easier if one stays within the lift envelope. Thermal flying is much more demanding because the "strong lift" that is constantly present on the slope is absent. The closest "thing" to slope flying on a thermal field are huge thermals that come in packets at certain time intervals and are developing over a particular location.
The model has to be flown a bit faster when thermaling. Tighter circles, when thermaling, is achievable through aileron and rudder coupling utilizing elevator (I couple manually - as needed). The tighter the circle, the more important is to understand the "limits" of the model. At a certain "turn radius and velocity" the model will tip stall if it slows down too much. This behavior is not abnormal; however, larger scale models (i.e. I find that 4 meter scale planes are more "forgiving" when it comes to tight circles and tip stall). In my opinion the "tip stall behavior" of the model is acceptable and predictable.
Finding lift is easy with the use of Picolario. In addition, air density plays a huge role in terms of how the model behaves. I have flown this model at sea level as well as 3740 feet above the sea level in Calgary, Alberta CANADA. My findings are that the model behaves "more favorable" in denser air. For example, I was able to fly slower and turn tighter circles at sea level than 3740 feet.
Landings are a bit longer at the thermal field. I utilize the spoilers and elevator to control the speed and elevation when landing.
In Part II of the ASW 28 review for ICARE Sailplanes, I will focus on electrifying the model. This "electric" alternative provides the pilot more freedom to fly this model virtually anywhere and eliminates the dependency of aerotow pilot. In addition, slope flying becomes a non issue "whether the slope has sufficient lift". If the lift is not sufficient simply turn on the motor and either ride the light slope lift or seek thermals.
In conclusion, I have to admit that it is hard to beat the quality and the design of the Let Model ASW 28 in the 3 meter scale plane class. The overall package is definitely there for the design and performance. I will continue to fly this model on slope and thermal fields alike. I like this kit so much that I ended up buying another kit. The brand new kit is currently sitting in my basement "just in case".Last edited by AMCross; Aug 16, 2006 at 09:33 AM..
I see that the second part of the review will be dedicated to a powered version, but not being able to wait I'd like to ask is anyone can comment on the wing strength of the 3m version: is the wing itself and the way it is mounted strong enough for safe flying with the extra weight of the motor and the large battery in the fuselage? I understand that it is always easier to fold the wing with a heavier fuse, but is the model designed to fly with that extra load? Or does become borderline dangerous?
I've ordered this model, the desicion was based on this review and recomendations. There are some delivery time on the model, but I want to have all the other equipment ready for when I get the plane.
This is what I'm thinking:
HS-125 for the ailerons
HS-81 for the brakes
HS-81MG for elevator and rudder
HS-225MG for tow hook and retract
5 cell IB1400 batterypack
8 chanel micro synth receiver
Will this servos be OK or are the 81's to fat for the wing? Are the 225MG's overkill, should I just go with 4 81MG's in the fuse? Or something all different?
Thank you for your help!
For ailerons I recall that JR 168 fit the best for two reasons:
(1) They were flat enough that they would not stick out of the skin
(2) JR 168 is a reliable servo to use
I do believe that the HS 81's are too thick for the wing airfoil.
For the breaks I would suggest a smaller servo - I do not think you can fit the HS 81's. The skin is a bit skinny to fit the HS 81's.
The rest of your thoughts for electronic "set-up" are fine. You may have to be a bit creative to fit in one servo for both aerotow and retract - I decided to use 2 servos for a much easier fit. I'm utilizing the "scale tray" seat, seatbelts, etc.and the fit is fine.
My personal preference is not to use 5 cells; however, that is your choice. I run 4 cells in all my models and I have never had any servo problems. To me it seems that individuals that continue to have "chronic" servo problems tend to use 5 cells – however, this could be a coincidence.
Good Luck, I'm sure you'll really enjoy the model.
I used HS81mg's for the ailerons - no problem, they might be 1mm too thick, but it isn't an issue.
The brakes use tiny 9g servos (I think) Saturns or similar. They work flawlessly and need only a small amount of torque.
Rudder and Elevator are multiplex ms-x3's I think, HS81 size anyway.
Every time I look at this model it makes me smile, just wish I could afford a big Let model, the workmanship is superb.
This is a nice kit. Fit and finish rivals anything I have seen so far. My equipment will be HS 125's for ailerons, Dymond D60 for brakes, HS 85 for elevator, aileron and tow hook. This one did not come with a retract which IMHO is not needed on a light weight 3M ship. There are some problems with the kit. The elevator control rod has some resistance due to the bend in the wire going up the vertical fin. The rudder horn was so close to the rudder surface it only allowed 1/2 right rudder throw. The stab is misaligned (bolt holes). The airframe weighed in at 38.5 oz. This kit came with no hardware, no servo covers, and no instructions. The Let web site has a manual but it lacks the basics.
I want to keep the glider pure.. But dont have easy access to slopes. I have easy access to huge grass field .
Adding electric motor , i am afraid will ruin the flight characteristics and add too much weight .....
What would you recommend?
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