Jump to content

Mini Jazz builders hangout.


Kevin Fairgrieve
 Share

Recommended Posts

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

Link to comment
Share on other sites

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.

Link to comment
Share on other sites

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?

Link to comment
Share on other sites

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

Link to comment
Share on other sites

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.

Link to comment
Share on other sites

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

Link to comment
Share on other sites

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

Link to comment
Share on other sites

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

Link to comment
Share on other sites

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

Link to comment
Share on other sites

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

Link to comment
Share on other sites

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

Link to comment
Share on other sites

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

Link to comment
Share on other sites

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

Link to comment
Share on other sites

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

Link to comment
Share on other sites

Posted by Steve Hargreaves - Moderator on 19/10/2013 10:11:06:

Just joining the Jazz Club......I have a Mini Jazz kit under then bench & a plan that Kevin sent me ages ago (I'm sorry Kev I still haven't built her!!! embarrassed) & some servos & an ASP15 so I'm pretty good to go.....when I find some time.....

Now now Steve, you know you can make time. The Maxi Jazz that started me off sending you the plan has had many flights now.

Kev

Link to comment
Share on other sites

Well the bench has been tidied & all the parts brought out from their various hiding places.....thumbs up

Just poring over the plan it seems a pretty straightforward build...I intend to angle the ASP at 45 degrees so the silencer exits underneath the fuselage. & I'll probably build up a cowl around the engine rather than fit the moulded version.

Where I am confused however is the slot cut for the tailplane (I have the MHS CNC cut wood pack).....it has significant positive incidence. The plan appears to show it at zero relative to the wing....any ideas whats going on?

Also a couple of other questions to Mini Jazz builders.....what tank did you fit & where did you source the U/C??

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

 Share

×
×
  • Create New...