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TN Folland Gnat


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I don`t see a build thread on this so far other than Tony`s own.

I have always been impressed by this aeroplane since the Arrows flew them. Also, when airshows were held at Gaydon I remember the commentator announcing that a Gnat would be coming in low and fast from the right which it did very close to the spectators. It was scarcely visible and the sound followed later.

No point in doing a blog on this but any observations I make on the build will be reported and photos put on later.

I have cut out a kit for myself. Power train will be FMS 3s fan and YEP 40A esc. I have dug out a very tiny servo and will probably use this to fit a rudder.

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Hi Martin

I've just finished my version, you shouldn't find too many problems but will be interested to see how you tackle some of the details.. I was a bit of a lazy git and used TN's wood pack which apart from the ply bits was really nice soft balsa. I think using soft throughout is key to achieving the weight, mine is 21.5oz ready to fly. Hasn't flown yet but I'm looking forward giving it a go.wp_20200131_17_14_04_pro.jpg

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dfd16d18-5ea9-44fd-af56-e84ba9fbe4ea.jpegMartin

build the Provost first . Great model and flys ok . But then build the Gnat and OMG... amazing .. such a great looker and flys so much better , smooth and with less power . Cruises on half.. your going to love it !!

Steve

Edited By Steve Jones 2 on 15/02/2020 20:16:26

Edited By Steve Jones 2 on 15/02/2020 20:17:02

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  • 3 weeks later...

Got mine finished at last, a longer build than I anticipated. A problem point was that one of the the outer sides did not fit, despite being identical to the other. I should have given it more attention because it governs the tail position. The turtle deck kept splitting down the pencilled in centre line but I got it fitted OK eventually. I was in two minds as to whether to cover the wing before fitting and risk damaging it when sanding the upper intake parts but this worked out fine. The tail and fin plus any possible fus. parts were filmed before assembly.

I decided to add a rudder to make the model more versatile and intended to fit the servo under the deck but forgot, so it is just at the front of this with a 2mm carbon link rod.

Weight is 22oz with a 2200 Lipo or 23.5oz with a 4Max 2600. My stock of 2200`s are seriously below capacity due to neglect so may go with the latter after a test flight.

Pics.

gnat 001.jpg

gnat 002.jpg

gnat 003.jpg

gnat 004.jpg

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I've built mine with four servos, and kept the control arms inside the fuselage. It's added a little extra weight of course, and I only had 9g servos available for the ailerons. I also decided to make the ailerons a slightly bigger chord, and hope they can be used as effective flaps too.

For the finishing.. Clearly film covering a small, curved model when built is a pain, and paint (to a decent standard) adds rather a lot of weight. What do you recommend? The current weight RTS but no covering or paint is 610g.

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Love the build myself and my son are both building TN Mini Jets. I have recently found time to start the Gnat while my son has started the Hunter.

We are both using the FMS 3S unit and while I am finishing the Gnat as a Red Arrows one, the Hunter is going for camo finish, but have considered it being finished in silver.

Both aircraft types lend themselves to many options on colour scheme.

Both should be finished in time for some decent flying weather - I hope.

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Posted by Graham Stanley 3 on 09/03/2020 12:17:43:

........................................

For the finishing.. Clearly film covering a small, curved model when built is a pain, and paint (to a decent standard) adds rather a lot of weight. What do you recommend? The current weight RTS but no covering or paint is 610g.

I can't help you with the weight of film, but tissue covering (to hide the wood grain) followed by paint added a total of 56.5gm to mine. The vinyl decals added another 4gm. There is a photo of it (without decals) on the other TN Gnat thread.

Mine also uses 4 servos and the all up weight ready to fly with a 4s 2200 Lipo is now 680gm.

Dick

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Posted by Graham Stanley 3 on 09/03/2020 15:51:44:

Thanks both. I'm concerned about the weight and (lack) of thrust. I'm measuring about 440g of thrust, 3S set up. I was hoping for more installed thrust, and potentially even more in the air. Time to go an get a fresh battery and retest..

HI Graham, I ran a static test on my 3S FMS unit and while kitchen scales are variable in the level of trust, I did unsurprisingly find that the battery pack type made a difference; the lower the C rating, the lower the power. Using two different manufacturer packs (both 35C saw about 27g variance), but using the better pack to repeat the test when the room temperature was 8degC cooler saw a drop in thrust of 24g.

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Covering such curvy fuselages with film is a bit of a pain but I don't think I could have got anything like a comparable finish with tissue and paint without adding a load of weight. I have no idea how much weight the Oracover I used added, but the overall weight came out on target.

I haven't bothered with testing static thrust, I'm not sure it's a particularly reliable indicator. I'm just going to chuck it and see when the weather gets better.

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  • 3 weeks later...

I've since flown my Gnat. After two less fast throws the third got it away, and it flew very well. Initially, a tad of a handful as the ailerons needs trimming. I forgot to throttle back until reminded, so fast, small, and a bit tricky to hold level. But once I managed to feed in the trim, absolutely lovely. Not for the faint-hearted, as the roll rate lives up to "twinkle" rating! On the next flight I fed in even more exponential, as well as reducing the throws to about 25%. Roll rate them a little less than scale, so will be increased for the next outing

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