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DYNAFLITE DAYDREAM 
Name DAYDREAM RCM PROTOTYPE SUMMARY  Ever since the creation of the class, the simple 2-meter polyhedral sailplane has been the staple of thermal and slope soaring. Most of the built-up kits in the class are geared toward entry-level builders and fliers and most have conservative, easy to build, flat-bottomed airfoils and light weights to aid in thermal detection. With their new Daydream, Dynaflite retains the virtues of easy assembly and light weight, but also added robust structure and modern airfoil technology to instill a higher performance level. The Daydream was delivered in a 3.5" x 6.25" x 37" box with a full color label showing a brightly decorated classic polyhedral soarer. The founder of Dynaflite, Mark Smith, is a multi-time National Soaring Champion whose exploits are legendary and his picture on the box is a reminder of the credentials of the new design.  Construction: Full-size plans are printed on a single rolled 36" x 50" sheet and are bolstered by a nicely done 32-page instruction manual. I skimmed through the manual and the plans before starting construction. As is my habit, I punched out all the die-cut parts first thing. I have built Dynaflite kits in the past and let me say that they have greatly improved their die-cutting. It is now as good as the best I've ever seen. Great Planes Medium and Thin CA's were used for most construction, with some Great Planes 30-Minute Epoxy and wood glue here and there. The tail is built over the plans from various sizes of 3/16" balsa sticks. After framing it up, I hinged the elevator in place so it could be sanded and tapered with the stabilizer. The same was true for all the steps for the fin and rudder. The tail feathers were ready for covering in about 90 minutes. The fuselage is a simple balsa box. First the 1/8" balsa front and rear doublers are connected to each other using 1/8" x 1/4" longerons. These are sheeted with 1/16" balsa (make a left and a right) which is then cut to the outline. It would have been nice to have the outer fuselage outline pre-cut then assemble the doublers and longerons onto it. Plywood bulkheads are used at all stations. Before installing the bulkheads, I drilled 3/16" holes in them to serve as guides for the supplied Great Planes plastic tube-in-tube pushrods. From #1 bulkhead to the just behind the wing saddle, the bottom of the fuselage is 1/8" plywood. The remainder of the fuselage bottom and all of the top sheeting are 3/32" balsa cross-grained sheeting. It's easier to install the pushrod sheaths before completing and planking of the rear fuselage - guess how I relearned that? The nose block is balsa and you will save yourself a lot of sanding by cutting it to rough shape before installing it. After rounding off the corners of the fuselage, the last step is to cut off the canopy per the plans. Fuselage assembly took about two hours. Wing construction is a robust variation of the classic floater glider. The quality of the die-cutting really showed here in that all the ribs fit perfectly. Unusual for a glider of this class, the Daydream uses the S-3021 airfoil which has proven itself in glider wars and which is easy to build in wood. Also unusual is that the spars are 1/8" x 3/8" basswood, rather than the 1/8" x 1/4" normally seen in 2-meter gliders. The inner panels of the 4-panel polyhedral wing are sheeted from the spars forward, forming a very robust D-tube structure. The Daydream calls for a rubber-banded wing and two 1/4" dowels are supplied for the task. However, since I really dislike rubber-banded wings, I modified the Daydream for a leading edge dowel and single trailing edge bolt. I added a 3/8" balsa doubler on the forward root ribs (back to the spar) and a similar doubler at the rear 2" of the root ribs. In the outer wing panels the leading edges are not sheeted and the spars revert to balsa - but the stresses are much lower and the lighter outer wing structure helps assure quicker control response. The wing was built in four separate pieces using the supplied angle gauge to set all the rib tilts at the dihedral joints. This made it easy to sand out all the wing panels in relatively small subassemblies prior to joining together. 1/8" plywood is doubled up for the center dihedral joint, and a single layer is used on the outer polyhedral joints. I have never built a wing that came together better at all the dihedral joints. Not called for and probably not needed except for my piece of mind, I added a layer of fiberglass cloth to reinforce the center joint. Total time to assemble the wing was about four hours. Back to the bolt-on wing mod. I used some scrap 1/8" plywood to double up the top of #2 fuselage bulkhead, and layered up some plywood and a maple block to accept the wing bolt. After the wing was built I aligned it with the fuselage, drilled a hole through #2 bulkhead and into the wing leading edge to accept the dowel, then drilled/tapped the back of the wing for a 1/4-20 nylon bolt. If you add up all the subassembly times, you will realize that I framed the Daydream in a single all day Sunday building session. Covering: The Daydream was covered using Top Flite MonoKote; Transparent Red with Gold trim on the flying surfaces and an all Gold fuselage with a Dark Platinum canopy. It is easy to inadvertently cause a twist in the open structure of the outer wing panels, so after covering they have to be carefully straightened. The instructions specifically state no washout is needed - and none was used. The tail surfaces were covered and straightened before attaching them to the fuselage. As is my habit, I MonoKoted through the hinge lines in the tail surfaces to seal the gap for efficiency. Radio: I have picked up several Cox Cobra 2 and 3-channel radios both new and off of EBAY. One of these was just the ticket for the Daydream. The Daydream plan shows two standard servos mounted in tandem as the fuselage is about 3/16" too narrow for a side-by-side installation. The review model was equipped with two Hobbico CS-35 mini servos that could have fit side-by-side, but that would have made the servo arms and pushrods a little too snug to adjust and optimize. Therefore, I opted for a tandem arrangement with the CS-35's slightly displaced toward their respective pushrod. I also moved my servos somewhat forward of that shown on the plan and got enough room to sneak the Cox receiver under the canopy instead of under the wing as shown on the plan. I used the Cox 4-cell "AA" battery box with alkaline cells - it's heavy but it also provides ballast. Only 1.5 oz. additional nose weight was required to reach the aft C.G. limit. The entire fuselage under the wing is also available for ballast for windy weather conditions.  Flying: The instruction book includes the recommended control throws, which I matched for the elevator and went a little over on rudder travel. An all night covering/finishing session got the model finished and ready to fly at a monthly club contest - then I slept late, arrived late, and lost out on practice time! Two hand tosses showed that the Daydream was flyable. This was a contest so I grabbed a timer, headed over to the winch, and commenced with the test flight! Not to worry, the designed tow hook position was right on target, and the Daydream tracked up straight and true without any control inputs. The robust spar construction exhibited negligible flexing and, after a modest zoom, I settled in and started to get the feel of the new bird. The balance seemed right, and control response was right on. As stated in the instruction manual the Daydream did not act like it needed any wash-out, with no signs of tip stall, even when I slowed it way down while squeezing out some extra time. Again, this was just the first flight but the Daydream inspired that kind of confidence in its handling. The light wing loading helped show off in the light morning lift, and the responsive controls made it easy to core any lift found. In the third round the Daydream hooked its first boomer, quickly turning into a speck for a max. Without spoilers it required a tight spiral (full left rudder and full up elevator) to lose several hundred feet of altitude. Later, I think I will fit it up with a hook type landing skid so I can land it hot and still get it to stop. I have always liked the simplicity of flying off a hi-start, so the next time out I took a Dynaflite standard hi-start for the launching duties. This is a total package, which includes the surgical tubing, braided line, split rings, ground stake, parachute, and a plastic reel. It was easy to get launch altitudes equivalent to the winch without a lot of stress on the airframe; the only thing missing is the winch launch zoom. With practice a little bump can still be achieved at release. The Daydream is perfectly matched to this hi-start and the combination provides the epitome of no-hassle sailplaning. With a fresh set of alkaline cells in the radio, this is an all-day sailplane package limited only by the pilot's endurance.  Conclusion: Dynaflite's Daydream is well conceived and executed so that even inexperienced modelers can build a good bird. At the field, the Daydream has wonderful handling that will help the Soaring novice succeed. Expert fliers will note that the good handling does not come at the expense of flight performance; with the S-3021 airfoil delivering better performance than is typical for this class of soarer. I think that Daydreams will prosper in both 2-meter and the new 3-function sailplane class. Novice and expert will appreciate the robust spar construction every time they step on the winch pedal. The Dynaflite Daydream is a winner. Photos by Dennis Adamisin. Reprinted with permission.June, 2001 R/C Modeler Magazine Editor: Dick Kidd Copyright © 2003-2008 Hobbico, Inc. Terms of Use All rights reserved. Do not duplicate or redistribute in any form. |
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