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Mark's Ballerina MK1

A pretty standard build, Saito FA40a powered

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McG 696913/01/2017 10:14:13
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2608 forum posts
987 photos

Very nice & tidy indeed, Mark.

... and you even thought about the 'paper tubes'... yes wink

Cheers

Chris

Mark Elen13/01/2017 12:30:36
401 forum posts
738 photos

Thanks for the generous comments guys.

I've got the engine on a test stand this morning and I'm just a little in awe. All set up, primed, turned the prop backwards till I felt compression, glow on, then to my amazement, the little Saito started first flick backwards.

So, first four stroke, first time trying the 'reverse flick' method and the first time I have ever started a new engine on the first flick. I'm going out now to buy a lottery ticket. wink

Cheers

Mark

Peter Miller13/01/2017 12:40:03
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10244 forum posts
1224 photos
10 articles

Yes, it does happen sometimes, A memory to treasure

Mark Elen13/01/2017 12:42:16
401 forum posts
738 photos

It certainly put a smile on my face this morning. Peter, do you have any experience with 4 stroke twins? Is it a good idea?

Regards

Mark

Peter Miller13/01/2017 12:53:29
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10244 forum posts
1224 photos
10 articles

I had a Saito 90 Twin about 30 years ago. A truly lovely engine. I never had any trouble with it and flew it in two or three models.Had to sell it in the end.

I have coverted the Saito 60T ever since it came out but never been able to afford it. One day I will have one but not in this life unless I win a lottery

Mark Elen13/01/2017 13:10:00
401 forum posts
738 photos

Sorry, I should have given you more detail.

My current building plan at the moment is:

Finish, cover and fly the Ballerina.

Start on the next project which is a 72" span Grumman Cougar from the 1980 Dennis Tapsfield plan. The plans for this show 2 off .25 2 strokes as power (shown as os25 Schnurle ported) I'd nearly fixed myself on a pair of SC25s, one reason being the price, the other being they would fit in the nacelles with no modification to the plan.

The only downside to this is the thought of a pair of screaming 2 strokes in what is a stand off scale model. I'm now wondering if a pair of Saito 40s would a) give it the power it needs and b) sound much better.

My concerns are if it is advisable to power a twin using 4 strokes and also the changes necessary to the nacelle to accommodate the longer engine/engine mount (it would need the firewall moving back in each nacelle about 1/2" which would then make the fuel tank bay too short to allow a standard tank to fit.)

One option if the 4 stroke is chosen, is to move the firewall back and construct a custom tank to fit the bay.

As I said earlier in this post, I'd pretty much decided on the SCs but now after running the Saito a few times this morning and it starting so easily and just wanting to run, its got me thinking again.

Any pointers?

Regards

Mark

john stones 113/01/2017 13:29:26
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10695 forum posts
1480 photos

No question 4 strokes would be fine in a twin, look at what size tanks you would be able to fit ? they're very frugal on fuel so you might have the room already ?

John

Peter Miller13/01/2017 13:45:50
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10244 forum posts
1224 photos
10 articles

Sorry, got the wrng end of the stick!!

I can see no problem with a couple of .40 four strokes. Yes you might need a little more space in the cowl and possibly a fraction longer cowl. In fact you might find that a model that size would be better with the larger props.

I haven't flown a four stroke twin but I see no problems. Get them set up well and that is it.

I have flown quite a few twins with SC engines and absolutely no trouble at all. Funniy enogh they seem a bit less noisy in a twin. My Grumpy Tigercub (SC 15s) goes like a rocket even after one engine stop. IT also is so forgiving that you can turn it into the dead engine with care.

Mark Elen13/01/2017 13:46:51
401 forum posts
738 photos

Hi John,

I'm just getting the plan ironed out in my head before I start the build. It will be a few months yet though.

nacelle.jpg

nacelle1.jpg

As you can see, the 6 oz shown is a nice tight fit in there, but there is a lot of unused space above it.

Cheers

Mark

Peter Miller13/01/2017 13:49:04
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10244 forum posts
1224 photos
10 articles

Simple answer Make a metal tank. See my Destiny build blog

john stones 113/01/2017 13:52:50
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10695 forum posts
1480 photos

Yep looks tight but there's different shaped tanks about ?

I agree with Peter as well, 2 stroke twins sound better than you might expect, seems to be a deeper hum to em.

John

Mark Elen13/01/2017 13:58:45
401 forum posts
738 photos

Hi Gents,

Many thanks for your helpful info. I'm looking forward to getting started on this one although it won't be for a while, Flaps, Retracts and a Twin, again all firsts.

Regards

Mark

onetenor13/01/2017 14:11:00
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1900 forum posts

It seems a bit odd that a couple of peeps can order Sanders from a company when someone else is told the firm only stock the flat bar type.Needs looking into I think Which is correct?

McG 696913/01/2017 18:18:14
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2608 forum posts
987 photos

Tomtom was right regarding the sander, Onetenor.

I went to the RC World website and ordered one when I saw the 'Great planes' sander...

Unfortunately, when delivered it was the "flat bar type"... I should have checked a bit more about the description. Silly me again. blush

So, just ordered one from the US. And I now hope Colin didn't make the same mistake? surprise

Sorry for 'clogging' your thread, Mark.

Cheers

Chris

Mark Elen13/01/2017 18:36:59
401 forum posts
738 photos

Hi Chris,

No problem, I went a little 'off topic' this afternoon too.😁

Cheers

Mark

Mark Elen14/01/2017 14:13:41
401 forum posts
738 photos

One servo box done:

image.jpeg

image.jpeg

image.jpeg

Cheers

Mark

Mark Elen21/01/2017 17:36:02
401 forum posts
738 photos

Hi all,

Seems like lots of time doing things, but not much progress, today I've been flying and got started on the U/C

image.jpeg

Engine has been on a he stand this week and is now we'll run in

Just nailing those last few jobs now before covering.

Cheers

Mark

McG 696921/01/2017 18:50:10
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2608 forum posts
987 photos

Still following, Mark.

... and quite a bit envious about that great wire bender... surprise

Cheers

Chris

Mark Elen21/01/2017 19:07:55
401 forum posts
738 photos

Hi Chris,

Don't get me started on tools.... I love em. I always work on the basis that 'you can't do the job without the correct tools' ........

This weeks tool purchase was a servo connector crimp tool to shorten the aileron servo leads so that they fit in the servo boxes without coils of cable and I can still take them out if needed.

image.jpeg

Cheers

Mark

Mark Elen25/01/2017 21:40:36
401 forum posts
738 photos

A little more done tonight:

image.jpeg

Not had much time this last couple of weeks due to work. Progress is being made, but it's slow going.

Cheers

Mark

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