SR Batteries Cutie Review
Kit and Accessories Available from:
Bellport, NY 11713
Review by Ken Myers
My kit arrived in its triangular US
Postal Service packing box on Saturday, July 27, 2001. Iíd looked the
prototype over at the April 2000 Toledo Show, and decided I just had to
have one. My X-250 had turned itself into my favorite plane, so I knew the
Cutie had to be added to my stable. I LOVE the way Larry designs.
I started by covering the front of F1
that would not be under the cheek cowl area, the little tab on the
top back of F2, the top of F3, the cheek cowl caps, and the inside of the
wing hold downs with covering to match the fuselage. Iíve found it easier
to do this BEFORE assembly. Of course, any of this covering that covered
an area where glue would go was removed.
By the end of Day 1, Tuesday, at dinnertime, the fuselage was formed up except for the hatch and bottom sheeting.
Day 2 started with the building of the unique hatch and sheeting the bottom. Here I "learned" to read ALL of the steps to a procedure before doing it. Iíve sheeted a "million" fuselage bottoms, so I just went merrily on my way, not noting that the landing gear holes needed transferring to and through the bottom sheeting. I was able to get the gear holes punched through from inside the fuselage, and then I used a pin to "find" the other holes for the landing gear mount hold down. I didnít put the holes in the rear mount provided for mounting floats.
Sanding the fuselage went well, but took a while. Luckily, I was able to do it outside, as there is a lot to sand away to make the hatch. It would have been easier, had I had the Midwest sanding tools Larry mentions in the directions, but they were ordered after the kit arrived, and I was already in the building stage. They did arrive on Thursday, so they were used to finish up the work on Friday and Saturday.
When attaching the landing gear, I was reminded how much I enjoy working with socket head screws. There is no slipping and gouging. Wonderful touch!
At the end of Day 2, Wednesday, the fuselage was done and ready for final sanding before covering, the tail feathers were glued together and ready for sanding and the right wing panel ribs were glued to the spar and leading edge.
The Cutie, in this construction stage, was taken to the Midwest R/C Society meeting, where it generated a lot of interest. Many folks found the construction of this plane unique and interesting. Day 2 also included the hour and a half round trip to the hobby shop for more thin CA.
At the end of Day 3, the wings were framed up and the fuselage covered. The horizontal stab/elevator and vertical stab/rudder were hinged and covered. Scott Rellinger came over that evening and we worked on installing the power system for his Herr P-51. Itís looking good, and the Astro Flight 15 on 9 cells is performing as expected on the bench.
At the end of Day 4 all covering was completed. Hinging was done while covering using Monokote style hinges, as used on all my planes. To see how I do this, check my X-250 article online. The horizontal stab and elevator become an assembly, as well as the vertical stab and rudder. It is easier to add the control horns and tailwheel strap at this time. The hatch tab and lock were added.
Day 5 started with the gluing in
of the cabanes, carefully adjusting and gluing on the horizontal
stab/elevator unit and then gluing on the vertical stab and rudder unit.
Finally the Monokote hinge, already installed on the bottom of the rudder,
was ironed to the fuselage, under the horizontal stab.
The "test flight" took place at the EFO flying meeting on Sunday, and proved to be a "non-event." The first light lasted about 10 minutes. The wind conditions were perfect - NONE! The temperature at 10:00 A.M. was about 80 degrees Fahrenheit. On flight 2, fellow EFO member Wally Brandel took the controls, as his Cutie is on back order from SR. Again, the plane generated a lot of interest. Several EFO members mentioned they have the kit, it is on order, or will purchase one soon. On flight 3, Gus Nuerenberg took the controls and flew it around for a while. EFO VP, Richard Utkan did all of flight 4, and this flight was timed at 8 minutes 30 seconds. Richard wasnít trying to see how long it would fly. He was just doing whatever he wanted. He discovered a very interesting flight characteristic. When the plane is throttled WAY back and full up elevator is applied, nothing happens. The plane just keeps flying straight-ahead, not even stalling or galloping, just flying slowly straight ahead with its nose pointed up. On flight 5, I did loops, stall turns, floated it around, and did several Richards, all the while talking about a lot of other things.
This plane, in a very good way, is
a no brainer. It is relaxing to fly, and can be flown "close in" and "far
out." It is definitely a Park/School Yard flier, and Iím sure Iíll be able
to fly it easily in the Oakland Yard golf dome this winter. If you are
looking for this type of flying, with a plane not made from the "shipping
container", this is it. It is easy to build, easy to fly and has real
Here are some hints that might help other builders of this plane.
Hint 1: To keep from building two right or left wing panels, carefully
glue the rods on the W2 ribs. They are the tip ribs. Slide a couple of W1
ribs about half way down the tubes and spaced out a little from each
other. Use the paperclip and rubber band "clamp" to hold things together.
Set the assembly vertically over waxed paper with the W2 rib lying flat on
the waxed paper and the tubes pointing toward the ceiling. Align the tubes
with W2 being sure they are square using the square gauge provided by
Hint 2: While gluing on the horizontal stab, if you donít have two carpenter levels to level the horizontal tail using Larryís method, use a carpenter level to level the wing hold downs while a heavy weight rests on the saddle. I used a brick. I used a balsa shim under the fuselage near the wing saddle to level the wing saddle. Then I used the level to level the horizontal stab as per Larryís instructions. I moved the level back and forth to check things, but everything stayed in alignment just fine.
Hint 3: Put the control horns on the elevator and rudder right after the covering is finished on those parts. Donít forget the control arm strap for the tailwheel.
Hint 4: Keep all of the small "punched out parts" and other small parts in a reusable lunch bag so that they donít "run away."
Hint 5: (Only applies if you are doing the modified version.) Remember to cut off the front tubes for the wing saddle if you are making a modified version like mine, so that the larger battery can slide through F2.
The following lists what I used during the construction of the Cutie.
single edged razor blades
2 oz. thin CA
less than 1/2 oz. thick CA
1 roll red Econcote (because I had it)
1 roll yellow Towercote
recloseable plastic lunch bag (small parts storage so they donít get lost)
Wing Area: 360 sq.in. (mfg.)
Fuselage: covered with wheels etc. 6 oz.
Total airframe weight inc. horns and all: 12.6 oz.
Motor/gearbox/speed control/switch/prop/spinner: 5.4 oz.
All Up Weight (AUW): 27.6 oz. with 6 #64 rubber bands
When Larry ships the kit to you, this is
what youíll find.
While the manual consists of a lot of pages, it should really be thought of as a "learning guide." The expert can get by just concentrating on the parts with an exclamation point, but it is a whole lot of fun discovering where Larry, the expert, made mistakes so that you donít have to. The beginner can be guided through the first aircraft with the equivalent of an expert standing in the room helping and guiding. While it may seem "massive", the pages fly by in no time at all, and the outstanding photos are a perfect compliment to the simple, straightforward and many times amusing text. The manual is your friend. Read it! Enjoy it!
First, I must state again, this power
system change is in no way necessary if you want a Park/School Yard
The modifications are listed below:
Mod 2: Make another battery support 3" long of 3/32" balsa. It can be made from fuselage side scrap. Be sure it is square and the grain is going across the fuselage. Cut the slot for this "new" battery floor in the sides of the fuselage doublers. Use the battery support slots already cut into the side doublers as a guide and extend the slots on the right and left doublers for 3" towards the tail from F2.
Mod 3: Make new 1/8" thick slots for the bottom front wing mount closer to the top of the fuselage side doublers and aligned with the bottom of the top F2 tab. The photo illustrates where it goes.
Mod 4: Open the servo tray for larger servos. I used HS-60ís because I had them, but HS-81ís would be appropriate as well.
Mod 5: Chamfer the motor mounts at a 45-degree angle so that the angle goes with the motor that is hung under the mount.
Mod 6: Leave out one on the cheek fillers on each side of cheeks. This allows easier access when installing the larger motor.
Mod 7: Note so much a modification but a note. Only put VelcroTM on the "original" motor mount for mounting the 6-cell pack. I used two parallel strips, even though it is not needed to hold the stock pack in.
Mod 8: Drill 4 new mounting holes in the motor mount about ľ" in front of the original holes. Leave the original holes alone if you are going to be switching back and forth between power systems. Also open up between the two holes in F2.
Mod 9: Make the front cross anti-spreader piece from plywood. I used 3/32" plywood cut to ľ" wide and glued appropriate size pieces of plywood to just retain the top of the motor. The picture shows what it looks like. Be sure to mount the anti-spreader before using the Nyrod motor strap.
Mod 10: Form a 4" piece of yellow inner Nyrod into a "U" shape by holding it between your thumb and middle finger while gently pressing together and heating with a heat gun. Do this slowly, with not too much pressure, and form a nice "U" shape. Let it cool before letting go. Cut a Ĺ" off of each side of the "U". Most likely it will have to be shortened a little more. Itís a try and fit kind of thing.
Mod 11: Use the original power system screws, if you have them, or purchase some DU-BRO No. 2 x Ĺ" Socket Head Sheet Metal Screw Cat. No. 381. Use the screws to attach the "U" to the bottom of the original motor mounts and the anti-spreader bar to the top. Slide in the motor and snug them up so that the motor canít move, but do not over tighten the screws. Be sure that you donít have a lot of up thrust or down thrust in the motor.
Mod 12: Shims made of small pieces of brass tubing may be needed to adapt the prop to your prop adapter for the Magnetic Mayhem.
With the modifications listed above and 6 RC2000 cells, the new All Up Weight is 37.6 oz. Thatís a 10 oz. weight increase. The new wing loading is 15 oz./sq.ft. The initial static amp draw is 26.4 amps and the initial static RPM is 9,900 using the aero-naut 8x5" and 6 Sanyo RC2000.
Flight tests of this power system were completed in the evening of Monday, August 6. The temperature at the field was 93 degrees Fahrenheit at 7:30 P.M. The wind was 10+ MPH. Even with the less than ideal conditions, this system worked well, and as expected. The plane increased its top end speed with no changes in trim from the stock system. It easily took off of the not too neatly cut club grass. Loops, rolls and stall turns were extremely easy to do when the throttle was opened up. Full up elevator with the throttle pulled way back was still a non-event, with the plane just moving forward with its nose up and losing altitude, but not rolling off, even at the higher wing loading. Using throttle management, which is required to fly this plane like it is intended, flight times were l-o-n-g with the Sanyo 1200SCRC cells and super long using the RC2000 cells.
With flight characteristics more like an old-timer, it seems that my prop selection is over-pitched. The next flight tests will be with an 8x4" prop.
While the Kyosho Magnetic Mayhem is an inexpensive and easily obtainable motor, there are a few other motors that will most likely be appropriate in this power/prop application. While it is impossible for me to actually test all of these motors, if you have one of these motors, you can mount an 8x4" prop, use 6 cells and see what RPM and amp draw you get. Remember that you are looking for a motor that will turn an 8x4" or 8x5" prop in the 20 to 25 amp range and between 9,000 and 10,000 RPM. The motor statistics indicate that these motors should work equally well in this application: Strontium 150, Graupner Speed 600 BB SP 8.4V #6309, Graupner Speed 500 SP 8.4V #6308, CEM-05 Cobalt, Astro Cobalt 05 7T#20 #605, and Goldberg Turbo 550.
The Cutie builds into an attractive, easy
to fly, Park/School Yard flier with the stock power system. With my power
system modification recommendation, it is easily convertible to a
trainer/sport plane, which is at home in a mixed field environment.
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