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Author Topic: DPC Sopwith Triplane - Kit Scale - Build  (Read 8132 times)
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Yak 52
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« Reply #200 on: May 01, 2013, 05:52:49 AM »

Hey Russ,

A couple of trimming questions from the giant leap thread:

What incidence does it have on the tail? The WW Widgeon has positive tail incidence (negative decalage) and that has a similar high drag centre with the parasol wing. I heard that someone (Bernie IIRC?) had built it with the normal 3 degrees negative on the tail but it had then needed massive downthrust.

So is there any scope for reducing the decalage? Although this alone would increase the trim speed, if you also remove noseweight you will maintain the speed but reduce longitudinal (pitch) stability.

This will depend on where the current CG is. It's possible that the combination of too much decalage and too much noseweight is giving you the power stall from excessive longitudinal stability. The model will try and fly at one speed and any extra thrust causes it to nose up. After a point just adding more and more noseweight will exacerbate the power stall.


One other thing: it looks like it's flying uncoordinated, ie slipping in the turn (not the only model doing this on Sunday!) I think you would get less phugoidy flights with more left rudder and some wash in (trim tab or aileron deflection?) on the left wing. The positive turn should put excess power into the turn and avoid the stall and slip pattern. The coordinated turn would also reduce drag.

I think your lower pitched prop idea is a good one, especially with a draggy tripe, but it may need a reduction in power (thinner motor?) too. What prop do you have on there? I'd be quite interested to see how Prop Picker assesses it.

All this is a stab in the dark without looking at the plan or specifics of the model of course....
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Russ Lister
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« Reply #201 on: May 01, 2013, 06:31:53 AM »

Just nipped in so a quick reply for now.
I will move the peg/ reduce weight first. Only earlier flights had bad sideslip - for a tripe I am fairly happy with it in that respect. I avoid rudder as much as I can - it was part of the problem I observed with your Beagle at one point (the rudder turning into down elevator. The down thrust I am using is not huge so I would accept a little more. I agree though - my Piets need a little positive on the tail
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Russ Lister
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« Reply #202 on: May 01, 2013, 06:57:29 AM »

A lovely calm day and puzzled by your 'un-coordinated' comment I have had to nip up the green. A lovely flight reaching about 30' high and over 20 seconds with a steady descent! Just a tiny bit more weight added. Hope to get a vid in the light tonight! ..... Then in the box for  Old Warden! Suddenly happy  Smiley
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Yak 52
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« Reply #203 on: May 01, 2013, 07:24:18 AM »

Russ, sorry, all I had to go on was Rich's video of your first(?) flight?

Went back to the night video you posted and it does look better (from what I can see)
Glad it's working, look forward to more vids.

Yes the Beagle was very sensitive to rudder, it was either opening up too much or spiralling in!
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Russ Lister
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« Reply #204 on: May 01, 2013, 04:16:50 PM »

Sorry Jon, yes, the earlier flight in the video was when the downthrust was increased but some noseweight removed in case it wanted to 'doff in'.

I must admit that I do like a more challenging model to trim ... I have 'easy trim' models sat in boxes once they have been sorted. I think I just enjoy the buzz of constant failure  Wink

Easy as Bostonians can be to trim, they certainly always seem to be a challenge to fly well at Impington in the narrow hall minus nets, minus tables, width available!
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Russ Lister
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« Reply #205 on: May 05, 2013, 04:07:28 PM »

The wind dropped again this evening .... that's at least twice this year!  Roll Eyes A vintage year already, compared to last year especially.

Another run up to the green, this time with my wife's phone camera.

Just under 700 winds on this I think.
Watch for the cat at the end of the video! .... this cat is not afraid of hunting my models!

http://www.youtube.com/watch?v=X-5YaqdXVKA
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Rich Moore
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« Reply #206 on: May 05, 2013, 04:33:10 PM »

Looks great!
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Yak 52
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« Reply #207 on: May 05, 2013, 04:36:16 PM »

Perfect!  Cool
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Russ Lister
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« Reply #208 on: May 05, 2013, 04:42:47 PM »

Not going to mess with it for the outdoor season, but it looks like it could do with a tad more right thrust and a little left rudder for indoors .... bit tight on the first circuit and opening up at the end.
If I can get the duration up and we get a calm evening at the free flight nats I might make up the numbers in one of the events ran by Bill Dennis (is the second event the one for any scale model?)
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GAJouette
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« Reply #209 on: May 06, 2013, 11:20:23 AM »

  Russ,
Great flying video clip my friend.
Highest Regards,
Gregory Jouette
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Russ Lister
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« Reply #210 on: January 02, 2014, 04:19:04 PM »

I decided to have a look over the Triplane for the first time in a while today.
I thought I would analyse things with an eye to making a few changes.
I spent over an hour picking out the blu-tack nose weight ..... this turned out to be over 12 grams!
The weight had gone up from just over 30 grams empty to over 52 grams with rubber and balanced to fly.
If my calculations are correct, I may be able to get a flying weight of around 40g ..... I'll let you know how when I find I can actually do it!
If I can't ... this thread will remain quiet!
 
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Don McLellan
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« Reply #211 on: January 02, 2014, 06:27:32 PM »

Hi Russ,

Somehow I missed the video of your triplane in flight.  A very nice flight!  And you are exceptionally brave:  there are just waaay too many things to run into when flying that model outside.

Looking forward to some more flight vids (even if the model is more than 40 grms  Cheesy)
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« Reply #212 on: January 02, 2014, 06:48:40 PM »

Thanks Don .... I'm in the process of fitting a GM63 CO2 motor that I am hoping will give the advantage I have mentioned.
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Russ Lister
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« Reply #213 on: January 03, 2014, 02:52:58 PM »

A simple and quick conversion for a start to see if the model performs any better with the GM63 motor.

Attached files Thumbnail(s):
Re: DPC Sopwith Triplane - Kit Scale - Build
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Don McLellan
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« Reply #214 on: January 03, 2014, 03:31:29 PM »

Looks very nice Russ.  Very interested in hearing how it flies.

Don
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Russ Lister
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« Reply #215 on: January 05, 2014, 04:43:09 PM »

Enjoyed a busy club indoor meeting at Bushfield today ..... pleased to say that the CO2 conversion for the triplane was a success  Smiley

It was a fairly cold and damp day so when the motor was not producing as much power as expected I put it down to this.
The model was flying OK from the start .... I just had to adjust for a turn. None of the early flights were much more than ten seconds though.
Flying with Pete Iliffe he has remarked on many occasions how important it is to keep the motor well oiled ... with this in mind I fetched the oil from the car and gave the motor a good oiling.
Next flight the model very nearly hit the ceiling! It was now producing far too much power. Playing around with the charge and the motor setting, but nothing really with the model, it was beginning to fly like this .....

http://www.youtube.com/watch?v=swqrAB-TRoA

Pretty happy at the result!
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Andy Sephton
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« Reply #216 on: January 05, 2014, 05:04:03 PM »

From what I saw this afternoon, the model was transformed.....or to put it another way, it looked just like the real thing. Well done!
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Too much thrust is never enough!
Yak 52
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« Reply #217 on: January 05, 2014, 05:07:51 PM »

Nice one Russ! Shame you didn't get video of that post oiling flight  Cool

Next flight the model very nearly hit the ceiling!

Nearly hit about 5 times you mean  Grin quite a heartstopper but you're a jammy beggar  Grin
Perfect greaser of a landing too.
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Pete Fardell
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« Reply #218 on: January 05, 2014, 06:14:55 PM »

Brilliant, Russ! Well done, and how nice when a plan comes together. Suddenly the CO2 conversion option looks tempting for all sorts of things.
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Don McLellan
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« Reply #219 on: January 05, 2014, 07:17:12 PM »

Very, very nice Russ!!
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Russ Lister
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« Reply #220 on: January 06, 2014, 06:21:13 AM »

Thanks all  Smiley

Still a little phugoid and sideslip, but I'm really happy with the transformation.

I did still leave my 'proper ' video camera at home - though I did take the camera bag!
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« Reply #221 on: January 06, 2014, 07:31:15 AM »

Thanks for posting that Russ. Grin
So good to see those vids.

Tony

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« Reply #222 on: January 06, 2014, 08:21:42 PM »

Russ,
From things you have said recently I gather that life has been on a bit of a downer.  Two calm evenings and a new model performing like that - wonderful.  When the hobby is going right other things seem to follow.  I hope so, you deserve it and I hope it continues for you all through the year!

John
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Russ Lister
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« Reply #223 on: January 07, 2014, 04:21:29 AM »

Thanks John,

Yes, just as things had become very good for us, I started having trouble with my shoulders. That has lifted quite a bit, I'm working better again and the models are performing for me again ..... surely it can't last?!
I will try to adopt a more optimistic approach from now on!
The triplane has certainly given me a renewed enthusiasm for scale.

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Russ Lister
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« Reply #224 on: November 09, 2018, 06:20:57 AM »

This one has been on the 'naughty step' since 2014!
It's the first time I have had a proper look at the model .... still got to fix the motor since the 2014 Nats.
It's not looking as tatty as I remember (all the main damage underneath) ... and it's not really the model's fault!
It needs slightly more power than the GM63 can give... especially for a ROG.
Bar the ROG problem it has given what are possibly the best scale flights I have had.
I locked the motor and mock engine in on the day of the Nats, so I'm hoping I can get the motor out cleanly and try the Gm63BB that I have.
Any experiences of what sort of power gain I can expect please?

I'm also going to try one of the wooden scale props I carved to see if it will actually fly with it.
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Re: DPC Sopwith Triplane - Kit Scale - Build
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