Radjet 800. First Flight.

...back better than ever

The arrival of the Radjet, my second and a replacement for the much loved and even more battered original, was much anticipated. The pretty original had been the subject of countless crashes as I struggled to learn the secret of getting it into the sky.

Along the way I learned about the delicate balance required with speedsters, and not to get the Radjet into flat spins form which it struggles to escape. I also learned, and relished in, the Radjet's capacity for rock-solid performance and high-speed stability.

My arrival of MkII caused some angst as nearly a year had elapsed since it's predecessor had retired after the incident with the sapling. Fortunately, and remarkably, my lessons learned were so entrenched that the pretty speedster launched and flew virtually perfectly.

Something that I never had the opportunity to appreciated before it was pummeled through launch training, was just was cleanly the Radjet flies, swift cruise at half throttle and effortless acceleration out of dives.

So, despite the nervous anticipation, the Radjet is back and reinforces my perception that this must be one of the best-value foam speedsters around...

Radjet 800 Unboxing

...what's in the box

The Radjet comes nicely poackaged - double-boxed with all items individually wrapped in plastic, so there's no damage.

The parts are nice-quality EPO, and the kit also includes an underside protector skid. The canopy is a loose moulded plastic part which needs to be attached to the base, which includes magnets for attachment.

This kit, the PNF, includes a pre-installed 1850kv motor, and a 20A speed controller, good for 100-120kph performance with a 4S battery.

All parts fit neatly together, with the tail & wings needing to be glued. Note that you'll have to add some sort of reinforcement to the wing joins, preferable some sort of spars or strips because the basic joint isn't going to cope with the wing loadings of this pretty speedster...

Radjet 800 EPO. Paddock Flypasts

...fast fun

Breezy afternoons don’t suit too many planes; of mine the pick are the Rarebear, Stinger and Radjet. This particular afternoon there was a fresh northerly blowing and I headed right into the paddocks, my favourite spot for speedy planes free of any obstructions making it great for low-level, high-speed flypasts.

I find the Radjet a very stable high-speed plane and able to handle wind with aplomb, so I had a great time speeding it upwind and downwind, always at full throttle as usual. Unfortunately, by the time I got to the fields this particular afternoon, the sky had got a little hazy causing glare.

As a result the video struggled a bit with the contrast and, although I tried to balance colours and lighting manually afterwards, it’s very difficult and the video still doesn’t look quite right.

Nevertheless, the flying is quite entertaining and the sky, although not as lovely as it had been earlier in the day, was still a lovely backdrop to the speeding Radjet...

Hobbyking Radjet 800. Sunrise.

...high-speed fun

The other morning I took the Radjet along with me. I hadn't flown it for a while so the launch is always a slightly tense affair, but my launch technique is still solid, with the Radjet launching into the growing sunrise. 

It's still pretty quick, although slightly off the pace when it was flying the little 850mAh nanotech, however it's quick, and stable enough that you can bring it over on super-low flypasts with confidence.

It was a most enjoyable flight and, as the battery died off, I turned the Radjet around for finals. The Radjet is surprisingly easy to land; with power off it is pretty floaty, and it glides in surprisingly easily.

Except this time when I had it headed into the tree behind me...

How to Launch a Radjet Part II

...celebrating a dozen happy launches

I have, on several occasions in the past, sworn I wouldn't fly the  Radjet again after suffering another abject failure. Yet, a few days later, I'd glued and taped the tough jet back into flying shape and was trying again. And again. And again.



So, having finally mastered the art of getting this flighty craft into the air, this is an opportunity to share the experiences I've had in the hope that I save other aspirant Radjet pilots some of the anguish I've experienced.

So I've done another video on launching a Radjet so you could see the launch trajectory a bit better. This was something of a masterclass, a celebration of long-overdue success with the often-exasperating little plane...

How to Launch a Radjet!

...I think I've finally got it

The last half-dozen launches I've had with the  Radjet have been virtually flawless, so I think I've finally succeeded in developing a robust technique that will get the touchy buzz-jet launched consistently.

Tip 1 - Opposite Aileron
I've been launching at about two-thirds throttle and about the same right aileron. This keeps the  Radjet almost perfectly straight on the launch and with sufficient power to maintain its trajectory. Don't worry about putting in a little too much right aileron as, if this is the case, all you need to do is back off a little and the plane will follow, as it wants to roll to the left.

Tip 2 - Trajectory
You need to launch it upwards at about thirty to forty degrees, so that you'll be well clear of the ground - no more snapped props or crumpled nose cones. In conjunction with power as above, this will have the  Radjet climbing smoothly.

Tip 3 - Power Transition
Once the  Radjet is stable and flying, perhaps a second or so after launch, all you need to do is ease up to full power and back off the aileron correction. If this transition is a little ugly is doesn't matter, as the plane will be high enough off the ground to give you plenty of space to correct orientation or direction...

Above Expectations

...a great morning's flying

Yesterday's weather was a remnant of summer; a hot day extending into a hot evening. Things, however, were to change, with the northerly bringing the annoying desert flies to be replaced by a cooling breeze off the southern ocean. Such events are portended by wild and unstable weather, as confirmed by forecasts of winds followed by rain. As such the plan was simple - get into the air as early as possible, wind permitting.

The morning turned out quite promising; a steady northerly was still blowing although now cooler. Unsure about flying the Phoenix 1600 in these unsettled conditions while still in its underpowered state, I opted for unpacking the Radjet. Having blasted the little jet around the field until the battery faded I glided in into the breeze for landing. It's flying a neutrally and stably as ever, exemplified by it's steady approach evening in the breezy conditions.

Determined not to risk damaging the Phoenix, I was nevertheless deeply tempted to try it out in these conditions; the breeze was still there, but steady and not too fast... Throwing caution to the wind I hauled out the big glider and lobbed it up on full power and left the throttle there for the duration, just to be on the safe side.

The flight was most entertaining, the Phoenix showing off it's exemplary flight characteristics and agility. It's also surprisingly fast - I am so anticipating the new motor, expected tomorrow or the next day at the latest!

Radjet 800 Second Attempt

...and crashed it again

That evening I did some searching regarding these lesser known flight characteristics of the Radjet 800. I found one video post indicating that the standard centre of gravity was too far forward and recommended moving it right back to the finger grips.

I had used the specified battery, a 1300mAh 3S unit, which pushes up against a stop in the fuselage. Easy. Simple. Except that this doesn't seem to work, at least not in my case. So I cut nearly an inch from the internal stop so that the end of the battery is now just inside the fuselage tunnel. I also moved the receiver position a little further back, the combined result of which was that the centre of gravity had moved substantially rearwards, although not quite as much as suggested in the video, but that should be fine.

The repairs complete and the Radjet suitably taped-up, I returned to the field with high expectations of a fun flight. The launch went well, with the plane zooming low over the paddocks towards the hill. Having launched with generous elevator based on my previous experience, I was dismayed to find that setting the elevator to neutral caused the Radjet to dip swiftly down. Not good, and by now the plane was well away and heading towards the woods.

I tried to turn it but was rewarded with a multiple snap roll instead, so now having lost orientation as well as almost losing sight of the plane, the result was virtually a foregone conclusion. A second attempt to turn and climb ended up off course and the little jet ploughed into the hillside, triggering the sudden flight of a pair of frightened birds.

It had been a while since I'd tramped the paddocks in search of wayward aircraft, but now I headed through the paddocks again, greeting the kangaroos as I headed up the incline towards the downed Radjet. The nose was still intact this time due to the fibre tape applied during repairs, however this had resulted in the nose to becoming a crumple zone instead which was probably worse. The canopy had also taken a beating with a section of the plastic shattered which would need fixing.

I'd chosen the Radjet because it looked different and fun but, so far at least, it hadn't worked out that way. Considering the problems I was experienci

ng it did cross my mind that the Rarebear probably would have been a better choice, with its conventional layout and more stable flight characteristics. On top of that it's also faster than the Radjet, although somewhat more expensive. Still a Radjet that doesn't fly isn't really much of a bargain...

With the parts in hand, I headed towards the car wondering what I should do next...

Radjet 800 First Outing

...and crashed it three times

I was very excited when I watched the video clips of the Radjet flying - high speed and lots of fun  on a modest budget appeared to be the order of the day. So I happily put the plane together anticipating an exciting outing when the weather cooperated with a calm morning.

Well, a few days later and I was at the field on a calm cool morning with cattle happily absent on the adjoining paddocks and the regular kangaroos contentedly foraging for their breakfast. I wasn't too sure with how much power I should launch the Radjet, so I opted for around two thirds throttle and hoisted it aloft at a fairly steep angle to give it plenty of air.

To my astonishment i was rewarded with the Radjet diving down rapidly and hitting the deck before I had a chance to react. With no apparent damage done and not to be put off, I put the battery back in place, refitted the canopy and had another go with a little more power.

Unfortunately the result was much the same with the Radjet again behaving like a brick, except that this time the tip of the nose was broken off. The brief flight has demonstrated clearly that the Radjet wasn't generating enough lift to stay in the air, even with the amount of elevator I had applied to try getting it airborne.

My final response was to add a healthy dose of up-trim on the elevators which finally managed to get the Radjet into the air at the third attempt. All was not well, however, as I quickly discovered that I could only keep the plane in the air by applying full elevator. Furthermore, as the Radjet rapidly disappeared towards the forested rise, I discovered it was turning to the right probably as a result of the elevators not being completely even.

I managed to turn the Radjet around to head back towards the field, however having to keep full elevator and compensate for its bent towards the right finally got the better of me and it plummeted to earth, just across the boundary fence but fortunately short of the flooded drainage ditch, in a brief flurry of scattered parts.

The damage was bad but repairable with the front of the fuselage snapped clean off. After a short hunt in the grass I also managed to find the battery which had disconnected and been flung out of the plane during the impact.

So I headed back to the car disappointed and with handsfull of parts. As always I didn't get a shot of the crash as it's a sad sort of occasion, imprinted on the memory so it doesn't really need a photograph...