|Wing Area:||310 sq. in.|
|Weight:||28 to 38 oz. (33oz as tested AUW)|
|Wing Loading:||21 to 26 oz/sq. ft.|
|Servos:||Hitec HS55 (2)|
|Battery:||Common Sense RC 3S 3850 10c|
|Motor:||Typhoon EDF-2W 450W|
|Fan:||EDF 400, preinstalled|
|ESC:||Castle Creations Phoenix 60|
|Manufacturer:||Electric Jet Factory|
|Available From:||Electric Jet Factory|
Many years ago, Andy Telzer designed the Minx 300, which was a great success. This bird took everything one wants to see in a jet - looks, ability, ease of flight -- and put it into the beginnerís hands. Andy allowed EJF to produce a kit of this bird and then later EJF.com came out with the Minx 400 kit for 70mm EDF units. These were great kits; however, they required a good amount of foam carving, which kept some novice EDFers out of the build on this bird. Now, using a combination of balsa built-up construction and lightweight epoxy gel-coated components that has a minimum of final assembly, this jet is a great first entry into the world of EDF -- or for the experienced flyer looking for a great handling Sport Jet to toss around the field!
The kit arrived in quick order with all the necessary parts to get this bird into the air.
As should be with any kit, the first step is to read the manual. However, the first few shipments of this kit will not come with a manual, because there was a mix up in the customs between the paperwork and the kits. At least the kits made it through! Note that subsequent shipments will come with a manual.
Due to this issue, this review may be helpful to be referred to during the build. Also, this thread in the EDF Forum can also be referenced.
The Sport Jet 70 comes with the fan unit already installed. The fan unit is designed for speed 400 brushless motors or similar sized brushless motors up to around 450 watts. If you wish to upgrade to 700watts, the plane itself will accept the popular HET 6904 EDF unit and the MiniFan 480 70mm unit, both available from EJF.com.
First, we must prep the fan housing unit so we can mate it with the fuselage and ducting. The fan housing is designed to be removable and needs some alignment pins to insure proper alignment. These pins are glued into the ply former, which will be later glued to the intake ducts.
Once the ducts are glued to the former, both assemblies are placed onto the fuse, in order to glue the duct assembly permanently to the fuselage.
After proper alignment of these previous assemblies is achieved, we need to mark the fuse so we know where to apply the glue for the ducts.
I choose to trace the duct where it contacted the fuse. Next, pull the duct off and use a soldering iron to cut the covering away from the fuse, then glue the duct assembly to the fuse. I like to use the soldering iron, as it will not cut into the wood.
With these items completed, all that remains is the fan assembly. The assembly of the fan is rather straight forward, as the unit is already installed into the housing, all that must be done is to install the motor into the unit and the impeller onto the motor. However, one thing that is worth mentioning is that the fan housing will need to be drilled to allow the motor wires to gain entrance into the fuse. A hole will also be drilled into the floor of the wing saddle, to allow these wires to access the fuse.
The tail is very straight forward and has a great amount of prep already completed for you.
The slots for both the horizontal and vertical stab have been cut into the plane, we just need to cut the covering that covers these slots, remove the balsa left in place and begin fitting the stabs.
With the slots open, slide your horizontal and vertical stabs into their corresponding locations and check for alignment. My vert stab was about a 1/4 of an inch too tall, so I slowly trimmed it down until it fit perfectly.
Once you have the correct locations and measurements for the stabs, mark them so you can remove the covering in order to glue them to the fuse.
The Sport Jet only requires two servos: one for the elevator and one for the ailerons. Hitec HS55's were used. On the underside of the fuse, aft of the fan housing is a hatch for the elevator servo.
The wings come about 98% complete. The ailerons are hinged; the control rods are installed; linkages are ready to go; lastly, the location of the aileron servo has been laser etched into the root rib.
Next step is to insure that the wing is mounted onto the wing saddle correctly. We need to install a blind nut for the wing hold down screw. The best way I found to do this is to install the wing and measure to ensure I have identical measurements on each side from wing-tip to horizontal stab tips. Once this is complete, using the wing hold down screw hole, drill a hole straight down through the wing saddle floor.
Since the kit has arrived, there appears to be some delaminating on the inner ribs. EJF.com has confronted this issue head-on and has added two addendums to the manual and kit. First - the spar has been replaced with a dense wood. Second -- it is recommended that a 1" to 2" strip of fiberglass be epoxied onto the wing joint. I had already been flying my airplane when there were reports of folded wings, so I did my glass strip as an afterthought. If I were to start another kit, I would not change the order I built them, with the exception that, before epoxying the ply servo tray onto the wing, lay your strip of glass onto the joint and glue the tray on top of this.
After all these steps have been accomplished, all one needs to do is setup the canopy magnets and give her a shot of paint or trim covering.
To add the magnets to the canopy, I use a very simple solution. I glue 1 set of magnets into the provided places in the cockpit. I place a layer of wax paper over this and stick the magnets that will go on the canopy into place, making sure to get the polarity correct. I then add some 5 minute epoxy and cover the back of the magnets, and then lay the canopy on-top and hold it in place with some masking tape. Works like a charm!
I also like to prove the aircraft will fly before I put too much time into painting it. I guess it lessens the pain if I plant one on maiden.
As with all model planes, these are built to fly, so the time had come to put some air under the wings of the Sport Jet. I had to wait several days for weather to cooperate with me so I could fly the jet. Finally, a perfect day came...light winds, sunny and above freezing temps, what else could I ask for?
I got the bird packed and headed to the field, where I went through the customary pre-flight rituals. Range checked, made sure all the parts that should go up did, and all the ones that should come down followed suit.
I had read in a thread that one of these had already met the balsa reclaimer via a hand launch gone badly, so I was a bit nervous for the first launch. I also thought this bird could ROG, but I was just as apprehensive to go this route. I decided I would hand launch it and be sure to give it a throw followed with some elbow gusto.
I walked out into the field and gave the bird one last check, everything was a'ok. I brought the throttle to "military power" and gave it a decent toss with the help of a small crow hop. Off it went and was climbing very well - we didn't destroy it, whooo!
The Sport Jet was climbing out like it was as ready to fly as I was to fly it. It needed a couple clicks of left aileron and we were off to the races.
I started out with a couple of passes by the field at a decent altitude to make sure everything was kosher. It appeared it was, so I then started bringing her lower with each pass. Something about a low flyby of a JET that rocks. After each pass I climbed to a decent altitude and swung back towards the field bringing the throttle up for the high speed pass. I love the sound of an EDF swooooosshh.
The Sport Jet goes where you put it. It is a very sleek airframe and slices through the air with no worries. The plane is plenty quick to keep an experienced pilot entertained but docile enough that a beginner EDF flyer should have zero issues.
With the completion of several high speed runs, it was time to wring her out a bit. Loops are large and good looking. It pulled through the loop just like a jet should. Rolls are a non-event. The plane does not have a rudder so snap rolls and rudder maneuvers are not possible. After some loops and rolls, I pulled the throttle back to check out the slow flying of the bird. At 1/4 throttle this plane stays in the air very well, which would be great for a newbie EDFer getting used to the plane. Inverted flight is as crisp as it is with the cockpit pointing "right side up." Just a click or two of up elevator was needed to keep it nice and level while inverted.
I opted to forgo the addition of landing gear; however, they can be purchased separately from Robert, at EJF.com. I decided to do this because I felt the Sport Jet would be able to rise off the ground even without the gear. I was right.
There are two ways to launch this bird - hand launch or a semi-traditional ground take off. I use both methods, depending on my mood. The belly take offs really impress the guys at the field and they are much more relaxed than the hand launch, so I tend to do that, more often than not. However, having that said, the hand launch is not a strenuous activity. It is very easy to accomplish a beautiful hand launch of the Sport Jet.
Landings need a small amount of planning in order to allow the Sport Jet to stick to the ground. The Sport Jet loves to fly and, if you allow it to kiss the grass with too much speed, landing you are not, and will find yourself back in the air, possibly running out of battery juice or smooth ground.
In the first flight, I brought the SJ by and swung out for a "jet" pattern. Keeping the pattern nice and wide and allowing the plane to bleed off airspeed while descending worked well and the plane simple slid to a halt.
The Sport Jet is pretty sleek and glides very well. Landings need to be made from a nice wide pattern with either very little power or power completely off. Just bring it in and allow it to slowly bleed airspeed off while getting closer and closer to the ground. The bird is not hard to land, it just needs to be coaxed down.
No, this is NOT for a beginner flyer. However, I would have no issues recommending it as a first time EDF for an experienced flyer. The Sport Jet is very well behaved and should bring a smile to any newbie EDF fliers.
I would give this plane a healthy thumbs up. In fact, I would give it two thumbs up!
I have been dragging the Sport Jet out to the field with me as much as possible. The current power setup is great for a beginner EDF enthusiast and is easily upgradeable for those speed freaks. This thing flies great on 450W -- I cannot wait to see 700W in her!
If you have been considering getting into electric ducted fans, and are looking for a great looking, quick building, wonderful flying EDF kit, here is your chance.
It is a great flying bird, give Robert at EJF.com a call and get one for yourself!
Last edited by AMCross; Mar 09, 2007 at 09:30 PM..
Do you know what your amp. draw is? How hard are you pushing that 10C pack? I have a Sport Jet almost ready to go. One of the recommended packs is a TP 3S 2050 Extreme. I was going to go with that, but was concerned over possible low flight times.
How much duration are you getting on your pack?
Mickeydee - I do know, but if I told you, I'd have to kill you.. I am out of town and cannot remember what the numbers are.. I was thinking about that last night, I should have put those numbers in the review.. I will be home Sunday night and will get those numbers for you.. I am getting about 8+ minutes of flying time..
I just looked through all the pics and noticed there are a few not shown on the review. I especially liked the great photo (did not like the outcome) of the battery and canopy ejecting, did the plane survive?
Your review and videos convinced me to order one as well as the same 2W motor you are using. I have all the rest of the equipment I need as well as several 2100mah 3s packs. What kind of flight times were you getting with the 3850's?
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