flashback-review (6K)
Flashback250 (13K)

By Heather Mardon

Construction

I am not going to reproduce every step here, just point out any areas that may need special attention. Construction begins with the fuselage which is a bit different from most other kits I have built. The theory is that the fuselage is less likely to suffer from "hanger rash" than the wing while left lying around.

The manual is superb with good photos and informative text. At no point did I need to pin any part to the building board. Every thing jigs together and glues together with thin CA. Virtually the entire wing is assembled like a jigsaw puzzle before any glue gets near it.

I had one part missing from my kit, a piece of 1/64 ply for the undercarriage sandwich. This was not too much of a problem as it was just a rectangular piece that I replaced with a bit of 1/32nd ply and sanded it down. The only point of the instructions that had me a little confused was the rigging of the pul-pull controls for the rudder & elevator. There were four openings in the rear of the fuselage but you only seemed to need three of them? It appears that the fourth cut out was made to keep the fuselage sides symmetrical. I used the spare hole to bring my antenna wire out.

TB-Flashback-bare (14K)
Here is the air frame ready for covering. Weight = 130g!

Covering

The kit is supplied with some clear "Doculam" covering film which I have used before with some success. However I chose to cover my flashback using Solite covering to give a more colourful look. (You can paint the Doculam covering) I was a bit more adventures in my covering this time around. I used a technique of prejoining panels of covering before applying them to the airframe. This enables you to have joins where there is no wood underneath. To do this you cut out your sections of film, strip the backing off and then lay them on a clean sheet of glass. Use a slightly hotter than normal iron (The glass sucks some heat away) and seal the seam between the two sheets. I found that you need at least 3mm for the seam. The sheet can then be carefully pealed off the glass and stuck down to the airframe. The other trick with Solite is to use a heatgun to shrink the film rather than the iron, just be careful to not hold it one place for too long....

Equipment Used

The kit is designed around the GWS EPS400 drive unit. I replaced this with a MPJet 25/35-20 MKI Brushless motor with a 4.1:1 gearbox. The speed controller is a MGM-Compro TMM18-3s. Power comes from a 3s1p KONION Lithium Ion pack that I was also keen to try out. I used an APC 9x6 'E' prop as Motocalc predicted a full throttle rpm of over 8500rpm (Slow fly props work best under 6000rpm)

2x GWS Naro Std & 1 x Hitec HS55 servo's were used along with a 555 Hitec Rx with the case removed.
With this equipment the all up weight was exactly 500g. Full throttle current is about 12.5A.

C.G & Control Throws

The battery was positioned to place the C.G at the front of the range indicated

Control throws were set to the "Low rates" settings given in the instructions.

Flying

Well You'll have to wait a bit for some flying pictures as I was by my self for most of the flights so far.
As for the maiden flight.... Well thats quite a story.

With everything looking perfect I commenced the maiden flight. This however was far from perfect. Lasted about 2 seconds after a hand launch, dived pretty much straight into the ground even after much elevator was applied. Damage was minimal, a broken motor mount. This was repaired and it was on to round two.
This time a different site was chosen suitable for a ROG takeoff. Well..... what a handful, she's up & down all over the place. After gaining some height I tried to trim it out but gave up, after a few attempts managed to land with out breaking anything.
It seemed it had all the symptoms of down thrust in the motor, although none was measured.
I'll skip the next too attempts (Which resulted in another broken motor mount) and cut to the cause of all my troubles.
The light bulb finally went off when I got my partner to hold the model while I revved up the motor..... Oh my god the elevator moved. Yes folks... I had reused a model memory that had a throttle to elevator mix enabled .... and it was set to 35% arrrrggghhhh

I have since had four flights on this model, all lasting 10+ minutes. If I was to comes up with a single word to describe how this plane flies it would be "Crisp". With the power system I have it is capable of vertical climb with a good bit of speed as well. The KONION cells are a great match for this plane and motor combo, good performance and good duration at a reasonable price ($75 for 3 cells).
I am about as far from an expert as you can get from a pattern flier but I am hoping that this plane will give me plenty of stick time for learning various manoeuvres. I did manage a bit of knife edge and a spin on top of the more usual loops rolls, cuban eights and stall turns.

Conclusions

If you enjoy a bit of building without being too taxing then this kits a winner. With a bit of imagination in the covering you can make yours stand apart from the crowd. Excellent pattern trainer for small field flying. I'm thoroughly enjoying mine.

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