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Oodalally

My latest quickie design

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D for Donald09/02/2014 19:22:06
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73 forum posts
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Aha! I'm not in the business of asking for trouble! I ask as the design is not too dissimilar from an Acro Wot and a few degrees of flaperon have worked reasonably successfully on one of those. However, near disastrously on Alex Whittaker's Super Slinky.

I'd be interested in your reasoning Peter.

AJ09/02/2014 19:37:35
143 forum posts
12 photos

Donald, I tried setting flaperons on my oodalally, to be quite honest they didn't make a lot of difference. The only effect I could see was an abrupt roll to the left as I switched it in. This was put down to one servo operating faster than the other. Once set it returned to straight and level. I also tried mixing in some elevator but again no real effect. Could just be my lack of flying finess, perhaps a better pilot than me might see some effect.

I am going to try building another wing next, this time splitting the ailerons so the inner half can be used as flap. I will use 4 channels so I can experiment with degrees of flap/aileron on the inner sections whilst keeping the outer half as pure aileron. The current ailerons are very responsive so I am thinking it should still fly fine on just half the surface.

Andrew

Peter Miller09/02/2014 19:42:20
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9807 forum posts
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Oodalally is lightly loaded and so will land slowly anyway. The wings are tapered meaning narrower chord at the tips.

Flaperons increase the effective angle of attack and this is more pronounced at the tip where the chord is narrower. You do not want more angle of attack at the tips, the opposite of washout.

Now add some aileron as you come in to land and that angle of attack suddenly increases on one side.

Now you may get away with it. You may not. If you don't you have a nice pile of scrap balsa. Actually, being light the model may not be damaged too much.

As I said, let me know how it crasheslaugh

D for Donald09/02/2014 20:04:35
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73 forum posts
8 photos

Thanks Peter - when good advice is given I take it. I doubt that I'll be trying them in that case !!

D for Donald09/02/2014 20:11:39
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73 forum posts
8 photos

Very interesting Andrew. Could the roll be as a result of the tip stall advised by Peter? Please post how you get on with the new wing. Careful experimentation is half the fun.

AJ10/02/2014 19:37:14
143 forum posts
12 photos

Well it will probably be a month or so before I can start the new wing as I want to finish the current build first, but I will certainly post my experiences as soon as I get it in the air.

Peter what are your thoughts on doing this? At the moment I am flying on reduced rates most of the time so I reckon there should still be plenty of control with half size ailerons and increased rates. I was going to simply split the ailerons 50/50, or would I be better trying say 60/40?

Worth noting that mine is electric so landings are carrying the same weight as takeoff. Unfortunatly batteries weigh the same full or empty sad

Andrew

Peter Miller10/02/2014 19:59:28
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9807 forum posts
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Should work fine. The most effective part of the strip alerons is out towards the tip. Not sure how much effect the narrow flaps will have but can't hurt.

I don't really think that 6 ounces of fuel makes that much difference as it is burnt off. Might make a bit if the CG was close to limits but mine is not.

D for Donald17/02/2014 17:29:33
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73 forum posts
8 photos

Finished my Oodalally now. Ic engine but it needed several oz of lead to get the CoG in the right place. Was this anyone else's experience with an ic engined version?

Shane Sunday18/02/2014 10:46:54
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342 forum posts
160 photos

Well she flew. The first flight I realised I had up thrust on the motor. so I had to cut into the fuse and sort that out. Last Sunday I managed to get to the field on a beautiful day and really take this girl for a spin. On the day I started with a 5 cell battery and this was sufficient, I dare say 4 cells would do it but would require more weight to ballance. The roll out required a little right rudder to see her off good and straight and when in the air only a few clicks of right aileron had her flying straight and level hands off. I need to sort my ailerons as the rolls require a lot of input but loops are fantastic. Cuban eights are a doodle and split S is just fun to watch. I've not attempted knife edge yet as I'm still getting use to her.

The first landing is as you said Peter, fast, far too fast and I had to fix the rudder as it struck on one of the bounces. The next 2 landings were better as I was getting use to landing speeds. This model can float down to a point and required a little flair in the end to make it perfect. all in all a lovely model to build and fly. Thanks again Peter.

Peter Miller18/02/2014 10:58:45
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9807 forum posts
1156 photos
10 articles

Great! Another happy customer.

Glad you are enjoying her.

Terry Walters18/02/2014 11:22:54
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1831 forum posts
1068 photos

Well my airframe is built and servos are in - just need to cover it and fit the engine! Only started it last August so for me not too bad!!!! Enjoyed the build Peter - just need to get it finished and then there will be another!

Terry

AJ18/02/2014 17:03:01
143 forum posts
12 photos

Shane, interested in your choice of batteries, I fly mine on a pair of 2200 3C in parrallel, ie 3C2P 4400mah which gives me 20 -30 mins depending on how I fly.

Andrew

Shane Sunday03/03/2014 15:13:12
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342 forum posts
160 photos

Hey Andrew, my model is quite a bit heavier than the original and I've had to make a few changes to get it to work. Hence the extra weight and battery choice. I got a couple flights with her today and she's real sweet. I've a video up on YouTube but I'm unsure how to link to it ushering my iPhone. It's called Oodalally electric 5th flight. It was shot on the iPhone and I'm still trying to get the hang of the landing speeds. Flown on 5s it's a pussycat. 6s she really comes alive. I've added some tape fins on the can of the motor to facilitate the movement of air inside the cowl and that's the sound you hear. It must be flapping off of a bit of gorilla glue. Sounds cool though I think.

Shane Sunday03/03/2014 16:49:29
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342 forum posts
160 photos
Rob Tothill08/03/2014 13:30:51
111 forum posts
8 photos

Hi everyone,

My Oodallaly has come on quite a long way. I have completed the fuse and put together the tail surfaces. One wing is almost complete too, so it won;t be long before I have to attempt covering my first model!

My modelling mentor noticed that on the plans the elevators do not appear to taper towards the trailing edge being shown as 1/4" thick all the way across with a radius on the trailing edge. He said that usually the rudder and elevators would be thinned towards the trailing edge to combat flutter. Does anyone know whether I should be thinning them or just leave them as they are?

Rob

Peter Miller08/03/2014 18:20:27
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9807 forum posts
1156 photos
10 articles

You will find that most sports aerobatic models do not have tapered control surfaces. It will make no difference to the flying perfomance.

In fact some models do not even round the edges off as this is supposed to reduce the chance of flutter.

If you look at a lot of full size aerobatic aircraft their control surfaces are just made from tube with virtually no taper.

Of course if you want to taper them, go right ahead. I will warn you that this will make the edges much more likely to suffer from hangar rash if you hit them against anything.

Rob Tothill08/03/2014 22:18:32
111 forum posts
8 photos

Thanks for your response Peter. I will leave them as they are, especially as I'm quite clumsy and my models do tend to suffer more hangar rash than most!

Shane Sunday26/03/2014 20:22:49
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342 forum posts
160 photos

heres a more spirited flight for you guys. I really enjoy flying this model now if I can just get that landing right.

D for Donald26/03/2014 22:10:05
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73 forum posts
8 photos

It certainly shifts Shane - I would say faster than mine with an OS 40 FP in it!!

Peter Miller27/03/2014 08:21:25
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9807 forum posts
1156 photos
10 articles

Very nice.

There were only three times that mine flew straight and level. Just after take off, when flying inverted and coming in to land. The rest of the time I was trying to tie knots in the fuselage.

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