Uno Wot wing build Question.

[TartanMac]

This is my first build of an aeroplane. I have been out the hobby for some time but wanna get back into it and decided I wanted a good beginner plane for my Weston UK .25 Combat engine. This was the only airframe I could find that met the spec I wanted and what a great kit and brilliant design in many respects.

It has come to the point of the wing. There is no mention of wing incidence and was wondering if there was a sweet spot ?

Also the wing in 4 channel config is completely straight. Does this airframe roll over on rudder or does it just yaw left and right when built like this ? Do I need to put in some diehedral to get it to roll with rudder ? Or does it do it anyway and is there a spot for that too ?

Great kit Chris Foss really did a great job with this one. Also just out of curiosity do you say YOU KNOW WHAT or is it UNO WHAT like Fiat uno ? Just wondering.

[Cuban8]

These are well sorted models, just build as per instructions and drawings. As for pronunciation, I reckon just say "you know what".

Edited By Cuban8 on 04/08/2017 20:49:25

[Biggles' Elder Brother - Moderator]

Well, first of all, as you say its agreat kit, well proven, so just build it as it is. If you are doing the 4 channel version, don't add dihedral and don't alter te incidence from where it sits naturally.

In the 4 channel version doesn't roll on the rudder it rolls on the ailerons. The rudder just yaws the model.

Now that's the ideal - in practice there is nearly always some coupling between roll and yaw - but it will be very small in this case.

BEB

[TartanMac]

There is 2 configs 3 channel and 4 channel 3 channel has alot of diehedral. If it won't roll on rudder in straight wing config I will be pretty disappointed and will have to change it.

[TartanMac]

Thanks biggles great info I don't wanna mess this up it really is a great kit. 62" wingspan and just 4lbs and the fuse it very rigid

[Biggles' Elder Brother - Moderator]

Yes - the 3 channel version needs dihedral - because it has no ailerons so you need to couple the rudder with the roll. But the 4 channel doesn't - the ailerons will do the whole job for you!

BEB

[David Davis]

At risk of being accused of pointless repetition TatanMac, just build the model as it is without altering the dihedral, wing incidence or anything else for that matter.

The Unowot was my second radio controlled model and it flew beautifully on an Irvine 20. Mind you, that engine had once powered a radio controlled car and seemed to produce much more power than a standard Irvine 20. I wish I had never sold it now.

You're going to love it with a high performance 25.

[Denis Watkins]

Yes those 20s were "tuned" David. I can still do it today. All internal ports were polished and smoothed and any

Internal corners in the air or fuel flow were smoothed out, with hand tools may I add

Good advice on the UNO WOT, as it is designed to the Nth degree and any tampering with Mr Fosss' alignment would be a mistake

[Dai Fledermaus]

I have a Uno Wot. The build instructions for the 4ch wing are :- 1.5 ins EACH win tip for the novice and 0.5 ins for the more experienced flyer. You'll find this on page 7 of the build manual. There is no mention of the wing being built flat. Hope this helps.

 

Edited By Dai Fledermaus on 05/08/2017 09:42:39

[Cuban8]

Just for info, does the Uno Wot come as a single kit with the option of selecting 3 or 4 channel version, dihedral settings, aileron cut-outs etc? Not had one myself but seen plenty over the field and they're good performers from what I've seen. Can't really see the point of building the three channel full dihedral wing version these days though, even as a basic trainer.

[Dai Fledermaus]

Posted by Cuban8 on 05/08/2017 10:21:21:

Just for info, does the Uno Wot come as a single kit with the option of selecting 3 or 4 channel version, dihedral settings, aileron cut-outs etc? Not had one myself but seen plenty over the field and they're good performers from what I've seen. Can't really see the point of building the three channel full dihedral wing version these days though, even as a basic trainer.

Yes it does. To maximize appeal you can build a 3ch or 4 Ch trainer from the same kit.

[TartanMac]

Posted by Dai Fledermaus on 05/08/2017 09:19:49:

I have a Uno Wot. The build instructions for the 4ch wing are :- 1.5 ins EACH win tip for the novice and 0.5 ins for the more experienced flyer. You'll find this on page 7 of the build manual. There is no mention of the wing being built flat. Hope this helps.

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Edited By Dai Fledermaus on 05/08/2017 09:42:39

Yep just read it. Good of you to point that out. I might go with 1.5". I like the way trainers roll with rudder so I can correct with aelirons. You get a nice tight turn I would like if anyone has experience with both. I had a BH Twister I did not like it much with the flat wing on rudder much. This CF Uno Wot I 'm sure will be way better.

I was planning on using a 9x4 APC I'm getting 16,400 rpm but that is with a pipe that is not tuned I will get the West pipe for it should get 17,000 rpm I think. That should be plenty thrust do you guys think 9" prop wash is enough ?

I have also never used a foam wing and also never fibre glassed a wing I have the zap epoxy and got rhino glue for the adhesion to foam from west and also for hinges. I plan on glassing and painting the whole plane. Should I cut a top sheet and bottom sheet or just wrap the wing in the cloth ?

Thanks for the help so far. I have seen that there were some Irvine 20 car engines on eBay my dad has the old pylon engine I heard they are actually pretty powerful. 25-36 is a great engine class especially with tuned pipes my Irvine 36 aero engine turns an APC 10x6 @14,000 rpm with a genesis throttle pipe that is the same as an O.S 46FX by memory I had an APC 10.5x6 @ 13,500 I know it gave 1.2hp Irvine made great engines. That 20 in the uno would have been great such a small capacity in such a large rigid airframe bet you got no vibration I have experienced that small engines in light small flexible airframes raise idle as the fuse moves when the engine fires and releases some energy by moving side ways. I like that there is no hollow pieces to act like a drum on this airframe too. Can't wait to fly it with the combat 25 just out of curiosity what prop did you use on you r Irvine 20 ?

[Dai Fledermaus]

Personality, I would only reinforce the wing join as described and cover the model in shrink film. I see no point in adding extra weight and giving yourself extra work by covering the whole model in a glass cloth and painting over it. One point, if you use a shrink film, paint the fuselage with Solarfilm Clearcoat, it will prevent fuel or oil getting under the covering and lifting it.

 

[David Davis]

Posted by TartanMac on 05/08/2017 12:46:10:

...Can't wait to fly it with the combat 25 just out of curiosity what prop did you use on you r Irvine 20 ?

I used a 9x4 and a 9x6 prop on it.

Two things confuse me TartanMac.

On the one hand you talk about building the model with 1.5 inches of dihedral under each wing tip to ensure maximum stability and in the next breath you speak about fitting a very powerful engine boosted by a tuned pipe no less.

If you are an experienced pilot why not just glue the wings together as they are so that you get a nice responsive model aeroplane with half an inch under each wing tip?

If you are an inexperienced pilot why are you fitting such a powerful engine to it? It could get you into trouble PDQ.

17,000 rpm eh? I hope you have understanding neighbours.

PS. To get 1.5 inches of dihedral under the wing tips, you need to sand away a small amount of the foam at the wing root to allow for the greater dihedral angle, leaving the bottom of the wing section intact.

[TartanMac]

I might be assuming the wrong thing basicly I'm thinking that if I build in 1.5" dihedral when I initiate a turn with the rudder it will start to slowly roll as it turns. I kinda miss that type of trait as every other aeroplane I had after a trainer won't do that. They just yaw and fly kinda side ways at the same time. I like using rudder then correcting the roll with abit of opposite aeliron then feed in abit of elevator as it slows with throttle it is good fun to have an airframe that fly's like that and is fun to use all 4 channels in that way for simple turns. The engine is really for climbing quickly then backing off to rpm under the pipe the West can idle down to 1,600 rpm and safely idles a 1,900-2,000 rpm it will use hardly any fuel at all if I,m just blasting it to climb.

That is really how I am looking at it to perform but I don't know if it will roll slowly on rudder at 0.5" or even 1.5"

The engine with a 9x4 should give 17,000 rpm

5.6lbs of thrust @65mph it should be perfect for climbing.

9x4@10,000 rpm is just on the pipe so nice smooth running and gives around 2lbs of thrust @ 40mph perfect for cruising on the way down and only making around 0.19hp my 9 oz sled should last a good while I can also fit in my 11 oz tank which I find brilliant.

That's my thinking behind the whole plane and engine combo. I had a Hawk by Tony nijhuis originally with an O.S 25SF then upgraded to a Leo 37 and then an Irvine 39 8x8@16,000 rpm I flew that for 2 years before crashing it doing a low fly past and clipping the ground with the wing tip so I should be fine with the Uno Wot. If not then at least I have peace of mind that the Uno is way stronger lol that hawk turned into splinters really fast. It was all over the runway.