Lucas's Ballerina

[Lucas Hofman]

To understand the modifications to Peter's design it may be useful to do a short introduction. I started aeromodelling four years ago, and only fly electric. Most fields are electric around here.

During the summer season I participate in F3A competitions, which strongly influences my flying style. Geometrical, gracious and not keen on "low and risky".

During the winter (which is long and very dark here in Norway) I try to build a bit. Nigels Tucano was my first (although a year or two late to join the mass build) but this year I will try to join the pack.

It is the first time I do a build thread here on modelflying so moderators, please let me know if I misbehave.

Well, let's get started.

[Lucas Hofman]

Since this will become en electric ballerina some thinking is needed. That should be allowed before Januare 1st without incurring the wrath of BEB I hope. I am keen on a program called motocalc to play around with batteries, motor and propellers. This has resulted in the following for the powertrain

Motor: Turnigy SK-3542 800 kv

ESC: 45A

Propeller APC 12x8E

Battery: Turnigy 4S 2200 mAh.

This results in a weight saving of 200 grams compared to the prototype. I hope to be able to shave off another 100gr to achieve an AUW of 1700-1750 grams.

Max power with this combination in will be around 500W and max thrust should be about 2000 grams. Expected flying time 6-7 minutes with good throttle management.

The local copy shop makes pdf files of the plan, which I can print out to pencil on. First find a place for the  battery plate:

Peter can design a whole plane and get the C.G. right. I cannot so I'd better make a big hatch so the battery can move around. Roughly from F1 to F5. That means F2 need to be split, and the opening extended downwards:

Edited By Lucas Hofman on 18/12/2015 15:52:53

Edited By Lucas Hofman on 18/12/2015 15:54:14

[Chris Barlow]

Will be following along. It'll be interesting to see if people come up with different ideas for an electric conversion or follow a generally accepted solution.

Where abouts in Norway are you?

[McG 6969]

Hello Lucas,

I will be following along as well.

Planning to build a Depron/electric version together with Dave Hopkin - well, he's my 'teacher' in fact, I'm a total newcomer - who started his build blog 'Anyone else for a Depron Ballerina'. Welcome over there for a visit, of course.

Cheers

Chris

Brussels, Belgium

 

Edited By McG 6969 on 18/12/2015 18:45:48

[kc]

Lucas you may be interested in my thread " Prima Ballerina" which is also electric.

Note that it has been stated that the dowel hole in F2 is placed rather too low and that it should be 1/2 inch from base rather than 1/4 inch. Actually drilled a little higher to allow filing to fit wing. Dowel slot in ribs should be altered too. This thread covers this point and also mentions changes to grain direction .

Edited By kc on 18/12/2015 19:07:17

[Peter Miller]

Posted by Lucas Hofman on 18/12/2015 15:47:59:

Peter can design a whole plane and get the C.G. right. I cannot so I'd better make a big hatch so the battery Edited By Lucas Hofman on 18/12/2015 15:52:53

Edited By Lucas Hofman on 18/12/2015 15:54:14

More luck tnan good judgement! I keep a lot of lead in stock just in case

[McG 6969]

Lucas,

Are you intended to move your battery box up to F5? In that case you have to move the servo tray as well, right?

If you stop your battery tray at F4 & move F1 around 40 > 50 mm forward, - depending on your motor length -, you have plenty of space to shuttle your battery around & no need to shift your servo position. Just a thought.

Happy calculating

Chris

Brussels, Belgium

ps: ... and i'm wondering why I consider Peter being a very humble great designer. Speaking of 'luck' after so many years of design... 

Edited By McG 6969 on 18/12/2015 19:33:16

[Geoff S]

Posted by Chris Barlow on 18/12/2015 16:56:29:

Will be following along. It'll be interesting to see if people come up with different ideas for an electric conversion or follow a generally accepted solution.

Where abouts in Norway are you?

Well I've gone for an SK3 4240 740rpm/v and a Plush 60 amp esc and I'll probably use a 3600 maH 4S LiPo. Unfortunately the motors I had in stock were either too big or too small and the highest current esc is a Black Mantis 50 amp. I have several Black Mantis esc and would have bought another except Giant Cod, who sold them, no longer exist.

My first ever trip abroad back in 1966 was to Norway. We went in my then girl friend's mini and it had to be craned on and off the ferry on the way from Newcastle to Bergen. We did it on a the then £50/person travel allowance but it proved a very expensive trip - I proposed a week after we got back Beautiful country.

Geoff

[Lucas Hofman]

Posted by Chris Barlow on 18/12/2015 16:56:29:

Where abouts in Norway are you?

Haslum, a suburb a little west for Oslo. It is a big country so we drive far to the various events and competitions. But often those drives are through beautifull mountain area's so that is part of the fun.

Edited By Lucas Hofman on 18/12/2015 22:43:43

[Lucas Hofman]

Posted by kc on 18/12/2015 19:03:49:

Lucas you may be interested in my thread " Prima Ballerina" which is also electric.

Note that it has been stated that the dowel hole in F2 is placed rather too low and that it should be 1/2 inch from base rather than 1/4 inch. Actually drilled a little higher to allow filing to fit wing. Dowel slot in ribs should be altered too. This thread covers this point and also mentions changes to grain direction

KC, I am following the Prima Ballerina thread. And thanks for the summary of errors to the printed plan!

[Lucas Hofman]

Posted by Peter Miller on 18/12/2015 19:08:15:

Posted by Lucas Hofman on 18/12/2015 15:47:59:

Peter can design a whole plane and get the C.G. right. I cannot so I'd better make a big hatch so the battery Edited By Lucas Hofman on 18/12/2015 15:52:53

Edited By Lucas Hofman on 18/12/2015 15:54:14

More luck tnan good judgement! I keep a lot of lead in stock just in case

Consistent luck = compentence. It is the same in F3A competitions: the same pilots correct just right for cross wind. If you ask them how the do it they often cannot tell you. The "just know".

[Lucas Hofman]

Posted by Geoff Sleath on 18/12/2015 20:32:29

Well I've gone for an SK3 4240 740rpm/v and a Plush 60 amp esc and I'll probably use a 3600 maH 4S LiPo.

My first ever trip abroad back in 1966 was to Norway. We went in my then girl friend's mini and it had to be craned on and off the ferry on the way from Newcastle to Bergen. We did it on a the then £50/person travel allowance but it proved a very expensive trip - I proposed a week after we got back Beautiful country.

It may very well be that I need to add weight in the nose to get the CG right! Then I can first use a bigger battery or step up to the 4240 moter. We will see!

Nice to hear that something good came out of your trip to Norway!

[Lucas Hofman]

Posted by McG 6969 on 18/12/2015 19:29:00:

Lucas,

Are you intended to move your battery box up to F5? In that case you have to move the servo tray as well, right?

If you stop your battery tray at F4 & move F1 around 40 > 50 mm forward, - depending on your motor length -, you have plenty of space to shuttle your battery around & no need to shift your servo position. Just a thought.

Hi Chris. No, the battery plate will stop at F4. But I think it is easier to make the hatch big. Easier with thick fingers and battery leads. Servo's will be up to F4 as drawn.

Moving F1 forward makes the fuse heavier, and the sides just longer then one sheet of balsa. I think it is not needed. The next post will explain how I think it can work.

[Chris Barlow]

Must be something about Norway as the wife and I spent 2 weeks there on our honeymoon in 2002. We spent a few days in Oslo then drove north through Lillihammer to Kristiansund then down to Bergen for a few days then back to Oslo for the Constitution Day celebrations on the 17th finally flying home on the 18th.

I agree it's a beautiful country and fantastic to drive through the mountains and Fjords.

Edited By Chris Barlow on 18/12/2015 23:33:48

[kc]

Don't forget that if you do move the servos forward then all Peter's carefully plotted holes for the 'snakes' in F6,7,8,9, & 10 will not be the same! The snakes are plotted so they run in a straight line to the servo arms in the positions shown. If you move servos & want to re-plot all the offsets for the holes then remember the fuselage drawing shows the UNDERSIDE view.

Also formers are drawn showing the front facing view. So if you drill a former as per the plan then if you hold it upside down over the fuselage underside plan with front facing front then you can see the holes line up correctly.    Hold the formers upright and the holes dont line up!    ( especially noticeable with F6 )

 

 

Edited By kc on 19/12/2015 12:14:56

[Peter Miller]

Sorry KC It shows the top view!!

I draw the fuselage top and side views. Add the heavy dotod lines and then plot the holes on the formers with dividers.

My snakes are not alwasy dead straight!!

 

Edited By Peter Miller on 19/12/2015 12:18:04

[kc]

I am expecting ( well hoping ) that by moving the motor bulkhead forward about 1.75 inches on my model that a 4S 3000 lipo ( now able to move forward by that much ) will just about get the CG right without lead. And I have found a particularly light piece of balsa for the tailplane, fin and rudder. So I am expecting that your 4S2200 will not be sufficient weight- but I might be wrong!

[kc]

Peter, I am referring to the printed RCME plan. That shows the underside view I think. Anyway the formers as drawn by RCME with holes drawn by them fit as though its the underside. I have just cut and drilled an F6 from the RCME plan and it fits the RCME plan (face front when inverted.) The RCME draughtsman has drawn the holes in F6 quite differently to your original. Almost but not quite a mirror image. I suspect that the RCME draughtsman saw the wing bolt plate and assumed it was the underside view!

[Peter Miller]

I think that I want to cry!!!!

Actually it is the right way round but the hole the hole on the left is 5/16 to far to the left.

Then F8, F9 and F10 are 3/16" too wide but it doesn't really matter because he has drawn the rear fuselage too wide at the rear so they will fit.

If the moderators could read my mind at the moment they would want to delete every other word.

Why can't the pillock draw the plans right. He obviously doesn't know how to use his computer.

What really makes me furious is that when people build the models I get the blame for errors not the (words fail me) draughtsman who can't stick to the original drawing.

You wait until my Peyret Mauboussin plan comes out, that should really be impressive.

[WolstonFlyer]

Obviously the CAD person likes to put their own little design changes in here and there, which is not a great, hopefully the model will still build from the plan though?

[Steve McIntosh]

Following, This will be my first build.

And just to make it harder going electric

[Chris Barlow]

Posted by Peter Miller on 19/12/2015 14:19:33:

I think that I want to cry!!!!

Actually it is the right way round but the hole the hole on the left is 5/16 to far to the left.

Then F8, F9 and F10 are 3/16" too wide but it doesn't really matter because he has drawn the rear fuselage too wide at the rear so they will fit.

If the moderators could read my mind at the moment they would want to delete every other word.

Why can't the pillock draw the plans right. He obviously doesn't know how to use his computer.

What really makes me furious is that when people build the models I get the blame for errors not the (words fail me) draughtsman who can't stick to the original drawing.

You wait until my Peyret Mauboussin plan comes out, that should really be impressive.

The big reason novice builders should wait for the other build blogs to appear. It's somewhat normal for plans to be slightly incorrect and for the builder to make alterations to get parts to fit and line up. Hence the term builder & not assembler! Also another good reason for cutting your own parts as you can measure the former, measure both places where that former fits and spot any errors before cutting.

All this rush to get parts cut and get started may result in a second set of parts cut and a few glue joints broken apart to be re-done.

Novice builders please hold back for these discrepancies to be discovered & don't be put off. With experience you'll soon learn to pick up on these anomalies in plans just like KC has highlighted.

[Geoff S]

IIRC, where I worked, the people who formalised the design draftsmen/women's drawings were called tracers. It seems the tracing paper must have slipped a few times when your design was drawn for publication.

Fortunately all my design work was electronics or software so I never got involved in mechanical design. Anyone flying in aeroplanes with Rolls-Royce engines should be grateful for that

Geoff

[McG 6969]

Peter,

I feel very sorry for you discovering what the 'redesigning computer-man' did to your drawings.

After the wing dowel & F2 mishap, this adds another dimension to the situation.

Please don't worry, nobody is going to blame you for this.

As a nationwide (and more) leading publisher, I hope they will be fast to correct this publicly by providing their subscribers and readers with an appropriate 'correctum'.

I'm afraid this could hardly convince lots of people to start building.

And I'm really not talking about me here.

Take care

Chris

Brussels, Belgium

[Biggles' Elder Brother - Moderator]

Posted by Chris Barlow on 19/12/2015 17:00:42:

The big reason novice builders should wait for the other build blogs to appear. It's somewhat normal for plans to be slightly incorrect and for the builder to make alterations to get parts to fit and line up. Hence the term builder & not assembler! Also another good reason for cutting your own parts as you can measure the former, measure both places where that former fits and spot any errors before cutting.

All this rush to get parts cut and get started may result in a second set of parts cut and a few glue joints broken apart to be re-done.

Novice builders please hold back for these discrepancies to be discovered & don't be put off. With experience you'll soon learn to pick up on these anomalies in plans just like KC has highlighted.

I would totally support this. I know you are really keen guys - but the whole point of the Mass Build is that there will be experienced builders to follow - you will have not one, but loads of step by step examples to follow and inform your build. But for this to work you have to allow them to start! We will start together on 1st Jan 2016 - some of the experienced builders will start straight away (they are chomping at the bit!) and once they start believe me they'll go much quicker than a beginner - simply because they don't have to "think it out" so much. So you'll have lots of guidance really quickly.

So, just be a little bit patient - remember a lot of the fun is the anticipation!

BEB