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Mass Build 2014 - Mini Jazz

Mass Build 2014 - Mini Jazz

The plan build article by Malcolm Corbin

Kevin Fairgrieve15/10/2013 19:59:36
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1614 forum posts
2886 photos

So kicking this off then.

I have built 1 Mini Jazz in the past.

And a scaled up version. Or as I call it a Maxi Jazz.

p2191149.jpg

I have dusted off the original magazine article with the plans on and will be getting a set of photo copies done on Thursday.

I have a BNIB SC12 ready doing nothing at all. Have a big supply of tree wood ready. Just need to get the mini servo`s undercart and RX.

Lets see what you are all doing, even if it is e@#%$*c

Thought ideas comments suggestions all welcome.

Kev

David Ashby - Moderator16/10/2013 10:07:18
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10934 forum posts
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Yep, me too Kev. I think I'd soon be bored by the other models that wouldn't get flown much so Jazz it'll be....electric of course smile

I'm just ordering the parts and plan although I haven't thoght about the power system yet, more on that later.

New and potential Jazz builders will want Malcolm Corbin's 1997 article which is available here on the site. It was a massively popular model when published to the extent that .15 two-strokes were hard to come by so some distributors told us.

karl grey16/10/2013 12:54:21
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100 forum posts
12 photos

Hoping to build this to and been looking at power systems all morning. Will be my first electric model so still scratching my head round the power set up.

Plans not ordered yet but will be soon

Sparks16/10/2013 13:06:12
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261 forum posts
55 photos

One question I have been trying to get an answer to is the change in the angle of incidence of the tailplane between the original RCM&E article plan and the latest plan MAG227.

Originally it was 0 deg, but now it is +3 deg (the main wing is also +3 deg but that has remained the same)

Does anyone know why the tailplane angle of incidence has changed?

David Ashby - Moderator16/10/2013 13:52:46
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Just made some enquiries Sparks.

Well I'm told that the plan had an error on the wing incidence which for some reason was corrected by tailplane incidence later.  That said, there's a correction in the Jan '98 issue stating that tail incidence shouldn't be negative (as printed) but zero!

I've just ordered a plan myself so I'll check to see what that version says but I'm told that the incidences should be zero on both, which I guess shouldn't be too difficult to do.

Kev, any thoughts?

 

 

 

 

 

Edited By David Ashby - RCME on 16/10/2013 14:07:40

Nev16/10/2013 14:04:38
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592 forum posts
221 photos

Surely if the wing is up +3 and the tail is up +3, the net result is 3 deg down trust on the engine, albeit scaled over the entire fuselage but I’m more than willing to be corrected.

I haven’t signed up yet but I will be building the mini Jazz too. In fact I already have the plan and I think a wood pack, that’s been sitting around for nearly 12 months waiting for me to start.

John Roberts 916/10/2013 15:03:16
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187 forum posts
167 photos

I am just starting to think about my build, especially with regard to a suitable power train.

I have a 300 Watt BRC motor lying around already LINK which might be suitable. Oddly, despite the motor reference number (2814), this has a diameter of 35mm rather than the implied 28mm.

Another option, which I am probably more attracted to, is a 12 quid HK offering LINK. This is the same size (35mm) and weight (102g) as the BRC motor but, if the quoted spec is accurate, should produce around 400 Watts on a decent 3S LIPO. With an anticipated all up flying weight of around 2 pounds this should be pretty lively face 1

Speed controller will be LINK if I use the BRC motor (just because I have one in my spares box) or LINK if I go for the more powerful HK motor.

Servos will probably be some TowerPro MG90s LINK because, again, I happen to have a few in my box.

More than happy to reconsider any or all of this in the light of more informed opinions!

Cheers,

John

Kevin Fairgrieve16/10/2013 16:21:05
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1614 forum posts
2886 photos
Posted by David Ashby - RCME on 16/10/2013 13:52:46:

Just made some enquiries Sparks.

Well I'm told that the plan had an error on the wing incidence which for some reason was corrected by tailplane incidence later. That said, there's a correction in the Jan '98 issue stating that tail incidence shouldn't be negative (as printed) but zero!

I've just ordered a plan myself so I'll check to see what that version says but I'm told that the incidences should be zero on both, which I guess shouldn't be too difficult to do.

Kev, any thoughts?

All.

Both of mine were built from the free pull out plans.

The Mini Jazz plan was photocopied for the first build (Mini Jazz) and then enlarged to 114% for the (Maxi Jazz) giving a wingspan of 49" and a fuselage length of 43".

Both had no change to either the wing or tail incidences.

Both fly impeccably and are lots of fun.

I too would like to see a copy of the latest plan to see if there is any significant difference.

Mini Jazz

Engine SC12 2st.

Servo`s 5 Hitec Hs81`s

RX FRSKY V8R7 ACCST

Battery 400mah 4 cell Mini AAA

Maxi Jazz

Engins OS40FP 2st

Servo`s 4 Tower Pro SG-5010`s Throttle 1x Power Pro MG90s

RX FRSKY D6FR ACCST Telemetry

Battery 2300mah 4 cell Eneloop.

One mod that I think everyone should consider is a 64th or 32nd ply doubler along the length of the fuselage between F2 and F3.

This was the result of a not to hard arrival, albeit into a high crop adjacent to our site.

Kev

Sparks16/10/2013 17:04:14
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261 forum posts
55 photos

My Motor thoughts:-

The weight of original glow motors, say OS10 or OS15 would have been in the range 120>200 grams.

So my thinking is to use an electric motor of similar weight to avoid unproductive lead weight up front to achieve correct CofG.

The Turnigy Easy match motors seem to fit the bill:-

1) Turnigy G10 1100kv

hobbyking.com/hobbyking/store/__45151__Turnigy_G10_Brushless_Outrunner_1100kv_UK_Warehouse_.html

2) Turnigy G15 950kV

hobbyking.com/hobbyking/store/__31771__Turnigy_G15_Brushless_Outrunner_950kv_UK_Warehouse_.html

These motors weigh 149g and 159g respectively, so in the mid-range of their glo counterparts..

Perhaps not the cheapest option, but they do look very robust with 5mm shafts and bearings compared to the more lightweight offerings with 3 or 4mm shafts. An important factor if you have seen some of my landings!

As a matter of interest, the G10 and G15 Turnigy motors have very similar weights/dimensions and electrical characteristics to the more expensive Eflite 10 and 15.

Sparks

David Davis16/10/2013 17:20:55
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3525 forum posts
635 photos
Posted by Sparks on 16/10/2013 17:04:14:

An important factor if you have seen some of my landings!

Sparks

Nonsense you're an expert!!

Or are you referring to your attempts to fly an autogyro?

smiley

John Roberts 917/10/2013 10:41:26
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187 forum posts
167 photos

Hi Sparks

Your thoughts on motors are interesting, especially the weight comparisons with the IC equivalents.

Like you I don't want to end up adding weight to the nose in order to get the CG right. The HK motor that I was leaning towards is about 50g lighter than your suggestions so it would be helpful to know from others who have already built a Mini Jazz how the CG turned out. Particularly whether additional balancing weight was needed on the nose or the tail.

The other issue to factor into this consideration is the weight of the LIPO battery & ESC. I intend to use 3S 2200s in mine because I already have lots of them. My expectation is that the combined weight of a 2200 (180g) and an ESC (around 50g) will probably weigh more than a tank of glow fuel and this ought to compensate for the relative lightness of the electric motor.

Thought and observations from others gratefully received.

Thanks,

John

Andrew76718/10/2013 17:44:10
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809 forum posts
4 photos

Not many MJ builders yet!!....I wasn't going to join in this year but the current build is nearly finished so why not?..Well there almost is a reason.....dug out the old mags and it looks a nice easy build, canopy and cowl in 1997 £6.50 inc postage...looking good!....2013 prices..£17.90 + postage!!!!!...What!!!..i know there has been inflation,but this much !!?...Is there a cheaper source? or has anyone made their own?..Please help if you can, otherwise i'll have to hold my hands up as MHS draw their pistols!!smile p

Andrew

Ian Jones18/10/2013 18:23:54
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3219 forum posts
1397 photos

Mini Jazz

Mine was originally built by someone else for IC and I rather uncharacteristically converted it to electric. As you can see it needed a lot of weight on the front. Some years ago now and can't remember what the problems were except that it seemed rather unpredictable. It showed the same weak spot a Kevins did in a hard landing though the damage was less serious on mine. I passed it on to someone into electric flight but haven't seen it since.

So I too would recommend beefing up the fus above the wing and it may also be worth planning ahead re weight distribution.

Ian

Kevin Fairgrieve18/10/2013 18:24:36
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1614 forum posts
2886 photos

Hi Andrew.

Welcome to the Jazz Club!.

My first Mini Jazz had a proper cowl and canopy from new. Post argument with the ground it was fitted with a "pop bottle" canopy. The cowl I found to be next to useless and a complete pain to fit. So the Mini Jazz still fly`s with a "pop bottle" canopyand no cowl. My enlarged "Maxi Jazz" has the cowl from a long dead Priory Models Silloutte.

This time round I am going to use a slightly smaller engine in the Mini Jazz, an .12 as opposed to a .15. I am hopping to do a built up cowl, Canopy this time? I think I may have a go at a home brew version as described recently by Tim Hooper in the August 2013 issue if RCM&E.

Kev

Andrew76718/10/2013 18:41:51
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809 forum posts
4 photos

Ok Kevin....I'm in!!

I'll try a built up cowl and i might even produce a plug for the canopy....going to use the electric bits from an Acro-Wot foam-e. With a bit of help i might even post some photos!..This is your fault Kev!!

Andrew

Kevin Fairgrieve18/10/2013 19:28:22
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1614 forum posts
2886 photos
Posted by Andrew767 on 18/10/2013 18:41:51:

Ok Kevin....I'm in!!

I'll try a built up cowl and i might even produce a plug for the canopy....going to use the electric bits from an Acro-Wot foam-e. With a bit of help i might even post some photos!..This is your fault Kev!!

Andrew

yes

Kev

Robin Kearney18/10/2013 19:48:56
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1077 forum posts
183 photos

I'm in wink

I've just opened the box on a West Wings Fournier, so that'll have to come first, but hopefully I'll get to the Jazz in the new year. Electric for me thanks to flying site restrictions, which is a shame because I have a OS10FP sitting in a box which would have been perfect!

r.

David Ashby - Moderator19/10/2013 07:16:17
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10934 forum posts
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613 articles

Ah yes, the good old Jazz Club .........smile

 
Just waiting for my plan at the moment.
 
Power system-wise I'm vaguely somewhere in the G10-15 area with a 40 amp ESC and 3s Li-Po but I'll probably start building it and see how light it seems to be before finally deciding.
 
 
 
 

Edited By David Ashby - RCME on 19/10/2013 07:16:43

John Roberts 919/10/2013 08:36:45
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187 forum posts
167 photos
Posted by Ian Jones on 18/10/2013 18:23:54:

Mini Jazz

Mine was originally built by someone else for IC and I rather uncharacteristically converted it to electric. As you can see it needed a lot of weight on the front. Some years ago now and can't remember what the problems were except that it seemed rather unpredictable. It showed the same weak spot a Kevins did in a hard landing though the damage was less serious on mine. I passed it on to someone into electric flight but haven't seen it since.

So I too would recommend beefing up the fus above the wing and it may also be worth planning ahead re weight distribution.

Ian

Hello Ian

Thanks for the photo and comments.

It does look like it is carrying lots of lead ballast at the front. Do you have any recollection of the motor/ESC/battery combo you used?

On the face of it the heavier motor suggested by Sparks LINK might be the preferred choice for my build.

Cheers,

John

crispin church19/10/2013 09:42:01
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442 forum posts
102 photos

i used a emax 2826 with battery right up front no lead needed on a 11x7

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