Showing posts with label 70mm. Show all posts
Showing posts with label 70mm. Show all posts

Tuesday, 14 June 2016

Fun With the FT Viggen.

...fast and fun

The Viggen has proved to be a great addition to the fleet, being fast stable and distinctive in the air. And, all this despite it being my first Flitetest build.

Most amazingly is how easily, and stably, it launches; being flat underneath you have to launch it underhand and yet it climbs stably without threat of stall or spin.



It's benign characteristics are a combination of it being a delta, but also certainly due to the calming effect of the canards, keeping the nose up and reducing the load on the wings.

You can turn the Viggen as sharply as you like and it won't do anything nasty. In fact, so effectively will it turn that it's almost like it has vectored thrust, being able to keep on looping almost about its own length.

And it's quite quick too; my version runs a common-or-garden ebay fan with a 50A ESC and is good for about 100kph. You could load it up with a 12 blade fan although I'm not sure how much aero load you'd want to put on a foam board plane...

Saturday, 30 April 2016

Firstar V2. 70mm EDF Conversion.

...flies and sounds better

The flight performance of the Firstar has been very disappointing, mainly I think because of the effect of the negative thrust angle which effectively just increases the wing loading.

So, like I'd long considered with the Floater Jet but never actually did, I've replaced the pusher prop with a low-mounted 70mm EDF installed directly on the body mount used for the stock motor tower with large cable tie straps screwed in place.



The EDF is rated at about 1.2kg thrust, far more than required, so I'm only running it at 60% speed on a 3000 4S lipo, which is more than adequate. In conjunction I've also replaced the stock 30A ESC with a 50A unit.

The thrust line of the EDF is virtually through the centre of lift on the wing, and this shows on launch with the V2 flying straight and then beginning to climb as the speed climbs, in stark contrast to its behavior with the tall pusher prop where it always nosed in and was reluctant to climb.

The much sleeker form, with the tower and foam shroud, means that it's also faster through the air, if required, and glides very well. And, if you needed more benefits, it also sounds brilliant...

Thursday, 28 April 2016

Flitetest Viggen. First Flight.

...no bites from the vegan

Preparing for the first flight of the FT Viggen I was both excited and nervous; it looked to be a great flying plane made a little more forgiving with the canards. However, having a completely flat underside, it was also the first plane that I’d ever have to launch underhand.


So, as I’ve done several times before, I headed into the depths of the paddocks to a launch spot with long grass, just in case I needed an arrestor bed. As it turns out not really but it didn’t hurt since, at my first attempt, the trajectory was too flat, and the Viggen simply disappeared gently into the foliage.


The second attempt was good, the Viggen holding an upward attitude till I could bump up the throttle and then it was on its way.