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EssexBOF

Watts New

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EssexBOF

Have finally completed the above model flies very well and completes an ambition to create a built up model to compete with the moulded models.

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Rafale

Brian

That does look good! can I have the tracing paper back now!!  :D

I will speak soon.

Nige.

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EssexBOF
On 02/05/2014 at 16:59, Rafale said:

Brian

That does look good! can I have the tracing paper back now!!  :D

I will speak soon.

Nige.

You will not get the same result from the tracing you gave me, Nige :rolleyes:

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Rafale

Had to try! B)  

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EssexBOF

Decided to fly the Watts New in the Bartletts event on Sunday flew well despite my best efforts to foul it up, by making C--- decision at crucial times. Still 5th against the Supra's, Explorers and Shadows was very pleasing with a home built model.

1 Wainwright, Paul Open 4992.2
2 Smith, Simon Open 4990.6
3 Fisher, Keith Open 4979.7
4 Mitchell, Peter Open 4946
5 Austin, Brian Open 4927.7

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Rafale

You should be well pleased with that Brian especially when you still at the early stages of the flight testing!

 

N.

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EssexBOF

Nice to receive the Eppler Trophy for this design plus other over the years, from BARCS, yesterday.

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Austin

Congratulations Brian and well deserved.  :thumbsup:

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EssexBOF

I now have plans available for those interested in building one rather than looking at all the moulded ones sitting in the corner on a cold rainy day ;)

PM me for details.

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EssexBOF

Makes it worthwhile:

Quote

 

Brian,

Many thanks! Brilliant plan, must have been a lot of work!

Another question, I'm planning to make the ribs with a CNC cutter. How did you make yours, also with a cnc-cutter?

Splendid Christmas Eve for me, studying your plans, the rest of our family is watching some nice movies, this is my own little adventure  ;-)

Regards,

Jacob

 

 

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Norman

nice drawings and glider.

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EssexBOF

Some pictures of Greg Englands Watts New in Tasmania. Has a few changes from my original, in having reduced dihedral, a moulded fuselage pod and sprung loaded elevator that allows the servos under wing, cutting weight in the nose.

He says it turns fine with the reduced dihedral using reverse differential on the ailerons. See his post on the RC Groups site

thumb-madien flight with spring in the elevator[1].jpgthumb-DSC_4151[1].jpgthumb-IMG_3050[1].jpg

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EssexBOF

The bit below is from Greg Englands reply on the RC Groups

I was interested in his bit on using reverse aileron for turning which seems to go against general use of ailerons

Those who fly  D L G might be able to comment on this as he mentions using this method on them

 

Servos are mounted under the wing, pull pull line to rudder uses Dacron 5kg breaking so no stretch and no slack. Lines were installed tight and that's how they have stayed. The elevator uses the spring string setup common on nearly all DLG's works very well and thinking of doing the same to the rudder. The aircraft can turn on a dime, using reverse differential on the ailerons same as the setup in my rudderless DLG (more down than up on ailerons) although adding rudder does make for a nicer turn. Having not much dihedral means the ailerons are very effective and the rudder less so. Probably handles more like a hot liner flying wise which I find Ok. May build a new centre section down the track as per Brian's original plan to see what the difference is. Like the Hotliner/Glider Brian very nice, you are truly a master builder

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mikef

Hello Brian, may I chip in?  It sounds as if Greg is using reverse differential rather than (or perhaps as well as?) reverse aileron.

I imagine the model in a banked turn.  With reverse differential, if the model keeps trying to increase its bank angle, out-of-turn aileron will hold up the inside wing and produce pro-turn yaw.

I have never flown a rudderless F3K model but I do find myself turning my F3Ks with a bit of constant rudder and slight opposite aileron now and then.  Come to think of it, I used that technique in my former life......

My main experience is in free-flight glider (yes no radio control!).   I had a lot of success models having a slight tip-to-tip wing twist, with more incidence on the inside of the turn - opposite aileron if you like.  The 'auto-rudder' was set pro turn.  The tip-to-tip warp was aimed at holding up the inner wing in the turn.  Given that the left and right wings are doing a slightly different airspeed, the outer wing travels further in the same time to get around in a circle.  The total twist was about 0.75 degrees in a 2.2 metre span.  This warp also makes the glider seek and hold thermals - the presence of an up gust gives a favourable drag redistribution - the inside wing approaches the pre-stall drag rise first.  (Both wing tips had built in washout on top of the overall twist.)

 

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EssexBOF
20 hours ago, mikef said:

Hello Brian, may I chip in?  It sounds as if Greg is using reverse differential rather than (or perhaps as well as?) reverse aileron.

I imagine the model in a banked turn.  With reverse differential, if the model keeps trying to increase its bank angle, out-of-turn aileron will hold up the inside wing and produce pro-turn yaw.

I have never flown a rudderless F3K model but I do find myself turning my F3Ks with a bit of constant rudder and slight opposite aileron now and then.  Come to think of it, I used that technique in my former life......

My main experience is in free-flight glider (yes no radio control!).   I had a lot of success models having a slight tip-to-tip wing twist, with more incidence on the inside of the turn - opposite aileron if you like.  The 'auto-rudder' was set pro turn.  The tip-to-tip warp was aimed at holding up the inner wing in the turn.  Given that the left and right wings are doing a slightly different airspeed, the outer wing travels further in the same time to get around in a circle.  The total twist was about 0.75 degrees in a 2.2 metre span.  This warp also makes the glider seek and hold thermals - the presence of an up gust gives a favourable drag redistribution - the inside wing approaches the pre-stall drag rise first.  (Both wing tips had built in washout on top of the overall twist.)

 

I tend to think he means Aileron Differential which he does actually state in his text. Even so I not sure I would try it myself. Martin Simmonds in his book on Model Aircraft Dynamics pages 137-139 goes into some detailon the subject.

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EssexBOF

Have now flown a new version of the Watts New, with a few mods. Main one is to lengthen the nose to use a lighter battery than the 2.2 3 cell as on the original. The version with the fibreglass pod was a failure IMHO from CLM Pro, as their pod has to short a nose to balance out and they have no Idea as to what the decalage is when asked. So reused the boom and tail feathers from that on a new OD fuselage with longer nose..

Needs a bit of sorting out, only flown it for the past week last Tuesday, but used it in  the comp at Little Bentley yesterday, for the last 2 rounds due to a servo mount breaking up on the original.

Managed to save approx 300 grams over the original. This was done by getting contest grade 1/16" balsa for the wing sheeting, but this gave problems when handling as it was so soft. breathed a sigh of relief after glassing he wing that it was a lot more servicable.

A couple of pictures for interest.

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EssexBOF

Have now uploaded a picture of the difference between the old version and the new one as a comparison.
The more observant will see that there is no former behind the motor. This is to allow the battery to be moved around till the best position is found The larger battery is 2.2 3 cell where as the the small one is 1300 3 cell, so reckon the an 850 3 cell would work OK for one run as in F5j

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EssexBOF

The use of C L M Pro fuselage sets, has been raised several times for this model. Those of you who have followed the thread,s will know that I did try one of these sets(what one not sure now), but it was not a success due to the short nose length.

Have checked their site, which does now include a set that fits the latest version that I made, regarding the nose moment arm. This is Set133.
They say that they are in the process of selling a ballast tube as well, for this version. This shows the nose diameter for a 32mm spinner diameter, so small motor/gearbox required.

It may be possible to put rudder/elevator servos under the wing, but access is a bit limited plus the rear wing bolt fixing will need to be moved forward, due to the wing seat being less than the wing chord.

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