Ultra-Micro J-3 Cub BNF
|Landing gear:||fixed mains, steerable tail wheel|
|Transmitter:||Buyer must supply a 4 channel DSM2 transmitter|
|Receiver/ESC:||DSM2 part # PKZ3351|
|Battery:||3.7V 120nAh Li-Po|
|Prop:||100mm x 60mm|
|Charger:||Battery powered single-cell Li-Po 0.3A charger|
|Available From:||Horizon Hobby and fine RC hobby stores|
Ultra-Micro J-3 Cub RTF
|Landing Gear:||Fixed mains, steerable tail wheel|
|Transmitter:||MLP4DSM 2.4 GHz 4 channel dual rate transmitter|
|Receiver/ESC:||DSM2 Part # PKZ3351|
|Battery:||3.7V 120mAh Li-Po|
|Prop:||100mm x 60mm|
|Charger:||Battery powered single-cell Li-Po 0.3A charger|
|Available From:||Horizon Hobby and fine RC hobby stores|
I have been really looking forward to the release of the ParkZone Ultra-Micro J3 Cub. It just looks like it would best fit the style of flying I want to do indoors in the smaller size rooms available to me, and it should perform well in the tree-lined street in front of my house. I love the demonstration stunts in the promotional video.
The RTF comes with its own transmitter and the four AA batteries needed for the transmitter. The BNF requires that the pilot have his own DSM2 transmitter to bind with the BNF Cub. I will be reviewing the RTF, and Dick Andersen will be using his Spektrum DX 7 transmitter to fly the BNF Cub.
Kit Contents J-3 Cub RTF:
Kit Contents J-3 Cub BNF
Items Author supplied for the RTF:
Items Author Supplied for the BNF:
Obviously the transmitter that came with the RTF J3 Cub will operate the plane. The RTF or the BNF J3 Cub will work with the following transmitters:
There was no assembly for either the RTF or the BNF. For both I simply installed four supplied AA batteries into the charger to power it. The RTF version required that four supplied AA batteries also be installed into the transmitter. I fully charged the 3.7V 120mAh flight battery that came with the planes that was only partially charged as shipped. That was all there was to do unless except to bind or rebind my Cub with a transmitter.
It was necessary to have the receiver in the J3 Cub Bound to the transmitter. They bound the J3 Cub to the receiver at the factory. It arrived ready to operate. Should I ever need to rebind the receiver to the transmitter it is a simple process. I did rebind the RTF version to confirm the process for this review.
RTF Rebinding the Transmitter:
BNF: Binding to the Spektrum DX7
The instruction manual that came with both the RTF and the BNF J3 Cub explained the binding process for all of the transmitters named above. Once the transmitter and plane are bound, I ALWAYS turn on the transmitter first and then the plane. When I’m finished flying I disconnect the battery on the plane first and then turn off the transmitter. The instruction manual also covers how to make some repairs to the Cub that might come up as the result of crashes affecting the motor or propeller shaft.
With the transmitter bound to the plane, I turned on the transmitter, plugged the battery into the plane and connected it in place using the hook and loop material on the bottom of the fuselage and one side of the battery. I was ready to fly. I visually inspected the alignment of the rudder and elevator surfaces making sure they were in the neutral positions. On my RTF they were in the neutral position, and so no adjustment of the trim buttons was necessary. I also checked to make sure the throws were in the correction direction on both planes. Control of throttle is on the left stick and rudder and elevator controls are on the right stick. Rudder is on what is normally the aileron control stick. That was normal in North America and when I first learned to fly it was with a rudder/elevator controlled glider and both controls were on the right stick just like the J-3 Cub.
The Ultra-Micro J-3 Cub is a three channel plane. The RTF Cub flew level with throttle set a few clicks below half throttle. As I increased throttle above that setting the Cub would climb with a neutral elevator. At full throttle she could climb into a stall (full scale planes climb in the same manner from level flight with neutral elevator when throttle is increased). When I gave her full power she climbed very well and would have stalled had I not started to hold in some down elevator during the climb. Holding in some down elevator on the right stick at full throttle she flew level and fairly fast. She could easily perform a small loop de loop from level flight. Turns were made with the right stick starting with rudder movement. When the Cub started to bank from the rudder input I would pull the right stick down/back a little bit to feed in some up elevator. At the same time I applied up elevator I eased off of the rudder and moved the stick back towards the center line and eventually back up to the neutral position at the completion of the turn. This combined use of rudder followed with up elevator was the combination I used for all turns. How long I held in rudder and elevator depended on how far and how sharply I wanted to turn.
The Cub had very good penetration and speed. She was not as fast as my ParkZone Ultra-Micro Mustang but she flew with good authority at full throttle. The Cub could be slowed down and still flew very well but she was not a floater at any speed. Most of my flying time was two clicks below half throttle. With that throttle setting she flew nice and level for most of the battery charge. At half throttle she was in a slight constant climb through most of the battery charge. I was having a ball flying my RTF Cub and had no trouble holding in down elevator as needed when I gave her more throttle.
She looks great, in my opinion, with nice looking Cubbish wheels, landing gear struts, decorative motor and her "Cub" paint job. The wing even has molded in ribs on the wing's top surface. She doesn't have the wing struts of the full size Cub but I could live without them quite nicely. The wing is undercambered which helps some with lift but makes inverted flight difficult as it requires almost all my down elevator (which was supplying up when flying inverted) to fly level inverted.
I have had no trouble controlling the RTF Cub in my normal flying. I have seen a few people try to fly their Cubs way too slowly and thereby induce stalls while turning at very slow speed. The turning stall could be a very hard snap stall, not something I wanted to do accidently, especially close to the ground. With that said, I have seen pilots in close to the ground stalls shut off the motor and crash with no damage to their Cub ... just to their ego.
With my normal flying my Cub behaved very well. I had no problems with control at all. At my favorite throttle setting she flew nice and level. She was not a floater. Some E-Zone readers have complained about the Cub stalling. I intentionally avoided stalling initially, and my normal flying would not cause a stall. As a test I used the elevator trim buttons to program in some down elevator for level flight at increased speed and that worked well. I just adjusted elevator using the elevator trim buttons as I changed speed. I didn't experience anything close to a stall during the first battery pack. Since I didn't want to accidently stall at slow speed I did it intentionally, on later flights at altitude to learn at approximately what speed and/or how sharp a turn it occurred. On a calm, windless day I flew outside and went up to about 70 feet and intentionally stalled the J-3 Cub in climbs and turns. I could climb into a straight stall at high speed. On this forward climbing stall the Cub dropped and then recovered in a straight line doing a little porpoising and she continued to stall until I added some additional throttle and leveled her out. Or if I turned too sharply when flying very slowly I could stall the Cub as she turned. Stalls in turns at slow speed were much more severe then straight stalls. Stalling in a turn the Cub would dive into a spiral. I had no trouble adding some throttle and pulling out with counter rudder and up elevator but it took some altitude and I would not want to do a turning stall at low altitude. ParkZone recommends low rates for the first few flights and this is important for newer pilots as they tend to over steer or over correct, with elevator and rudder. Using low rates lessened the chance of that happening with their reduced movement of the control surfaces. When flying slowly with high rates it would be easy for a newer pilot to apply too much rudder and cause the plane to stall while turning. To avoid the very slow speed turning stalls I just made wider turns and was ready to put in some up elevator when the inside wing on a turn started to drop and add some throttle when needed. By doing these intentional stalls at altitude, where there was time and space for recovery, I learned what not to do. Frankly, the type of slow flying that lead to the stalls was not something I was likely to do by accident. In my intentional stalling I learned it was best to be easy on the controls, especially at slow flying speeds and stalls could be avoided completely.
My RTF Cub was a very easy plane for me to fly. I enjoyed flying my Cub in a nice smooth fashion with a few acrobatic tricks and I want beginner pilots to have the same favorable experience. My flight tips to myself: Don't try to fly the Cub too slowly. Keep speed up enough for good air to flow over the tail section. Turn using the combination of rudder and elevator. Don't do anything stupid, especially near the ground. Fly the plane to the ground and land with power on when possible.
Since the BNF Cub had the same plane that was in the RTF kits, if I used the same transmitter that came with the RTF the results would be the same. Most of what was said above about the RTF version applies for the BNF version as well. For this review I used my Spektrum DX7 and then Dick used his DX7 to control the BNF plane. I flew the RTF for several flights before working on the BNF version. Based on my experience with the RTF version I programmed in 30% exponential for both ailerons and elevator (Remember that the rudder is on the transmitter's aileron channel.). I also programmed in throttle/elevator mix at +50. As I moved the throttle up my mix moved the elevator slightly down. I had to adjust the plane's elevator's initial position setting using sub-trim a little down for it to be in the neutral position at low throttle. With this programming the BNF Cub stayed in neutral flight as throttle was increased, the mix adjusted the elevator down. There was no need to adjust the elevator down manually on the transmitter as throttle increased. To climb it was now necessary to use some up elevator. With the programming described above the BNF version was easier to fly then the RTF version. Dick was thrilled with the way the plane performed for him with my transmitter and so he programmed his the same way. Dick had no problems flying the BNF version.
Flights can be started with a gentle toss forward from the hand or by takeoffs from the ground or a table. If flying outdoors with any breeze I recommend that takeoffs be into the breeze. If there is any cross breeze, corrections will need to be with the rudder controlled by the right stick. The Cub has plenty of power, and I have had no problems with my takeoffs as I use firm if not full power and fly straight and climb a bit and then reduce power and level off. I build up speed before doing any acrobatic maneuvers. I have seen a few pilots have some post-takeoff crashes when they took off at a low power level and started to turn without first building up some speed and they put their Cubs into a stall turn. Low speed turns close to the ground are not recommended as the Cub can stall in slow turns and drop somewhat quickly as described above.
I like to make three legged landings with reduced throttle on and land in front of myself just as I do with my 1/4 scale Hanger 9 J-3 Cub. When outdoors that is downwind, cross wind and then I turn the plane into the wind over the runway and fly level and slow down while flying straight forward into the landing. Indoors with no wind I still take the same approach and keep up my speed until I have completed my turn onto the final leg.
As discussed above a small loop de loop could be performed in level flight provided I had enough vertical space if flying indoors. A slightly larger loop de loop could be performed following a dive but the increased air speed was not well retained so only a slightly larger loop was possible. With no ailerons some acrobatic maneuvers were not possible. However, a number of tricks were still possible with the Cub. Two of my favorites were shown on the original demonstration video of the Cub with a one wheel touch while turning in a circle or partial circle. I love doing that. Additionally, the Cub does a great climb and with reduced throttle and hard rudder a wing over looked very good. When I kept doing that repeatedly I was flying as if I was flying in a half pipe. My favorite slope maneuver now can be done in a large gym or in front of my house. Dive, climb, hard rudder and full up elevator and I perform a corkscrewish barrel roll. I only have done that outside so far and at altitude because it is a trick in progress. (Translated that means I still mess it up at times.)
My favorite trick is simply flying in a very smooth and controlled manner around the street in front of my house. No jerky motions, no forced direction corrections. A loop, a wing over and a landing at my feet. My friends who haven't seen me fly before think I'm an expert. The smoothness of the Cub really conveys the control and an impression of skill to those who see it for the first time. It is also important that I feel confident so that I can keep calm and thereby look professional while flying.
When not flying I like to keep my Cub in its original box for both storage and transportation. The plane is held in place when purchased by two pieces of foam that were secured over the plane and held in place with masking tape. I could continue to use masking tape but I preferred to glue some Velcro to the top and bottoms of the foam pieces where they meet in the box. I used five minute epoxy to glue the eight of Velcro pieces to the foam. I used four pieces double the size of the first pieces of foam to hold the foam top pieces in place. These four larger pieces are held in place just by the Velcro. With the foam cover pieces held in place with Velcro my plane is safely protected in its box.
I do not keep my transmitter in the box as it can move about inside the box once the plastic tie was cut and removed. If I wanted to keep the RTF transmitter in the box I would secure it in place with a new plastic or metal twist tie so that the transmitter couldn't shift and possibly damage my Cub. If I am taking a trip and bringing my Cub I may use a reusable metal twist tie to secure the transmitter inside the box.
This can definitely be flown by a beginner. I recommend a little time on a flight simulator and a little ground school and recommend the first flight be outdoors in a large space and in calm conditions if possible. Indoors and the more confined space adds additional pressure which isn't helpful on first flights for beginner pilots. The larger the space and the calmer the conditions for the beginner the better. Beginners should keep the transmitter oriented with the direction the plane is flying until they get their head into the cockpit. Finally, in my opinion, the beginner should not fly much below half throttle unless they are about to crash or on final while landing. Indoors I have flown at 1/3rd throttle and some can fly on as little as 1/4 throttle. But over steering which beginners are likely to do are more likely to cause stalls at those slower speeds. The really slow flying is more for intermediate pilots and above. As mentioned above ParkZone recommends beginners use the low rates when first flying the Ultra-Micro Cub.
I only had to install the batteries in the transmitter of the RTF version and charge the flight battery. With the BNF it was charge the flight battery, bind the plane to the Spektrum DX7 transmitter and do some easy programming of exponential, throttle/elevator mixing and adjusting elevator sub trim. The Ultra-Micro J-3 Cub was a very nice flying plane. She went where I directed her and could do so even in a little breeze. She allowed me to show my hobby in front of my house to my neighbors and my non-flying friends. In calm conditions she flies so smooth and level I look like an expert pilot who is so good I can do it with what they mistakenly think is a toy transmitter and plane. The Cub's handling is definitely Hobby grade. Outdoors especially the Cub is the smoothest flying of the Ultra-Micros in my opinion and I have flown them all. As a Cub she looks great doing it. As described above I started by flying the RTF version and had no trouble controlling my Cub with the included transmitter. But with a programmable transmitter setup as described using first mine and then Dick's Spektrum DX7 the flying experience was even more enjoyable.
My thanks for the assistance of Dick Andersen and our editor, Angela H for their help with this review.Last edited by Angela H; Mar 30, 2010 at 09:25 AM..
|Mar 30, 2010, 04:21 PM|
This is my favorite indoor flyer. It flew perfect right out of the box. Way to go Parkzone. Can't wait to see what is next for indoor flyers. Great review Michael!!
|Mar 30, 2010, 05:05 PM|
Great review Michael, i agree with most of what you have said, after owning this plane for just over 2 months, it sure is a beauty
now i know the way it flys i just set my DX7 up with 80% DR and 25% Expo then just "Fly It!"
heres my latest vid for those that haven't seen it yet lots of flying styles in here
|Mar 30, 2010, 06:04 PM|
This is a good and complete review, thanks. How do you compare the flying speed with that of the UM P-51 that also has am undercamber wing ? I ask because our gym for indoor flying is pretty small. I can fly the P-51 in there but would be looking to buy the cub if it flies significantly slower.
|Mar 30, 2010, 06:12 PM|
|Mar 30, 2010, 06:20 PM|
|Mar 31, 2010, 07:34 AM|
I have had one for about two weeks now, still no maiden flight yet but SOON. I am a beginner pilot with only some heli experience and now some recent Ember indoor and outdoor experience. I think I am ready for the Cub, just don't want my first flight to be in my neighborhood where I have been flying the Ember.
I have the BNF with a DX6i and think I have the same DR settings as Chuck.
Because I am new, I like the mixing idea mentioned. If I struggle too much with the Cub and it wanting to climb too much I may try the suggested mixing.
Great info all...
|Mar 31, 2010, 08:59 AM|
|Mar 31, 2010, 09:45 AM|
On the BNF version, could you bind it to one of those cheap hobby king 2.4 GHz transmitters?
This one specifically:
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