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Power my Zagi


Phil May
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I'll try to keep you informed BB.
Shame your so far away, I'd love to fetch the Wild Thing and Weasel.
 
Interesting to see your club only allow's 2.4, have you seen my other thread.....Club Bans 35 MHz..........
 
Phil
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Your model will fly. Although you do seem to have removed a little more of the wing than most mods I have seen.
 
Most of the mods normally limit the changes to cutting some of the aileron away.
 
Where there is a CG issue, more frequently encountered with the glider version, where the Lipo is much further reward and the fuselage top can be made for a glider. The motor will be sited as far back as necessary to minimise work to the ailerons, the lipo being moved forward as necessary to achieve the required CG. The fuselage top then being modified.
 
The motor seems quite meaty, I am guessing an E-Max of some specification. If so I am using a smaller E-Max BL2215/20 , which pulls this around like a pylon racer
 

so I am guessing your model will be rocket like .
 
Look forward to hearing of your success and first flight
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Erfolg,
the motor is an E.MAX BL2215/25, so a lower kv than yours and I think slightly less power also.
 
The section cut out was tapered from 1"to nothing on the wing centre line ( a V shape IYKWIM ) I hope it was not a mistake........
Only time will tell, I'll let you know how it go's.
Hopefully it will have a fair pace
 
Phil
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It's ready for it's maiden, tomorrow if weather ok.
 
I have two questions I'm afraid,
 
Firstly, is it best to do a glide test to check trim.
And secondly, what is the best way to launch the model, I know that may be a daft question.
 
Thanks guys
Phil
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Some people like the "pizza box toss" (kind of like a HLG launch). Personally for my test flights on the Zagi I just got some cardboard, folded it into a "T" shape and taped it onto the bottom of the wing like a keel. Easy to hold for launching and folds out of the way for landing...
 
You could do a test glide but I'd just fly it check the CoG and go!
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As Ben has suggested, that is what happens in our club. In recent years, i have never seen a test launch as such, other than thermal gliders (powered or not).
 
Light the fire and a side arm launch, is pretty typical. On the first flight, normally someone else does the launching.
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BP......try and launch and then turn on the power....keep your carol singers away from the prop....or you wont be carol singing this christmas........i've seen two people catch the top of their launching hand with the prop...very decorative but deadly....
 
ken anderson ne..1 carol singers dept...
 
 
ps...carol singers=fingers.
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Hi Guys
 
It went well,
I did not bother with a glide test, just put it on full song and launched it like a frisbee.
It dropped a bit, but with a little up elevator she was off .
 
Just a couple of clicks on the trim and she was level, not that I stay upright for long.....
It is not fast, nippy would be the best way to describe it. I guess maybe 30mph + in a dive followed by a nice low pass.......this is the model to practice fast, low inverted passes.
 
Most of the first flight was on full power and I was only getting about 4mins before I started to notice a drop in power. ( it was cold today, so maybe that affected duration)
 
Second and third flights I was a little more reserved with the throttle and managed a couple more minutes out of the battery.
But these things are not to be flown slow - flat out is for me....
 
My conversion was a bit 'agricultural' IYKWIM, not very neat, but now I know it works I'll tidy it up.
 
I think I'll soon be changing for screaming, high KV motor if it will give better
 performance.
Thanks for the advice and Ken, I still have all my carol singers...lol
Phil

 
 
 

Edited By Big Phil on 20/12/2011 17:16:22

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I've started to tidy up the wiring,rx etc and was wondering,is it ok to cover the esc, which is in the old battery recess, with some covering tape to match the rest of the model, or is it best to leave it exposed to keep it cool?
 
I plan to make and fit a pod type of cover over the lipo so I may fit the esc under this and cut some vents.
 
Any ideas guys
 
Thanks
Phil
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ESC's benefit from being kept cool.
 
How hot a ESC can become does depend on a number of factors. If the ESC rating matches the actual amps it is handling, it probably will get hot. If the motor is continuously run at full power and not switched of (only the BEC operating), it could get hot. If no ventilation is providedthe risk of overheating is increased.
 
There is a danger in my opinion, if the esc is allowed to overheat, it could shut down, as one of my own has. It was operating at about 70% of its rating. I found that the motor shut down. I do not know if the BEC also shut down, as I was operating with a separate Nicad battery to the Rx. This occurred a number of times
 
I subsequently fitted a small duct ( a bit like the radiator ducts on (Spitfires and 109) about 1/8 * 2" wide, with the heatsink in the duct, thereafter I have had no problems.
 
I have seen very large intakes into the bodies of models, which seem excessive. I have seen some Zagi types with a hatch/moulding, which have pre-moulded louvers in them, which either work or do no harm.
 
ESC's should not be allowed to get hot.
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  • 2 weeks later...
Took it out again today to a local football field, actually it is the same field I got my little 'lecy bipe stuck up a tree........guess what, the darn trees have a habit of grabbing out at my models.........
 
Luckily it was low enough to poke down with an old tree branch......
 
 
Anyway, as usual I have a question .
The motor is bolted to an aluminium angle, which in turn is bolted through the foam (tube spacers used as not to crush the foam) but the angle plate is moving side to side a bit.
 
What adhesive is best used to stick the ali to the foam to stop this movement.
Any ideas,as usual, greatly accepted.
 
Thanks guys
 
Phil
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Phil
 
As with all things there are many solutions. Most though will involve some re-enforcement to spread loads and or create a hard point.
 
I would attach a 1/16" patch to the wing as a minimum thickness, sufficiently large to distribute the forces, that is generated when flying and landing.
 
I always have some reservations about sticking things together, when metal to wood, but you could epoxy your motor mount to the plate.
 
An alternative is that you could just put screws from the mount into the ply, although i would suggest 1/8" ply.
 
On can type motors, cable ties are often used.
 
There are many other ways, none right, none wrong, all depends on how you want to create a secure mounting.
 

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Thanks for that Erfolg,
 
I was thinking of using a normal two part resin to fix a piece of lite ply to the top and bottom of the wing and then bolt the ali mount through the wing, then bolt the motor to the bracket.
 
Is this type of adhesive ok to use with the foam on the Zagi?
 
Cheers
Phil
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Hi Phil
 
I tend to think that there are not many wrong glues as a concept, other than some will react adversely with some materials, some will take for ever to set, some set to quick etc.
 
In the case of a typical wing, it will be made from foam, often white (polystyrene foam), obechie veneer in the UK, some balsa, and a covering, these days often film, in the past wrapping paper.
 
So what is compatible?
 
In the case of the film, little will stick firmly to it. So on any jointed area, it is locally best removed, as little as is necessary.
 
With respect to the rest of it, wood and foam, PVA will do, foam friendly cyno (often called odorless) will do, but generally does not fill gaps and goes of quick, normally. Have you noticed all the qualifications, as within a group of adhesives, there are some variations, that you normally pay a bit more to have.
 
Sticking metal to wood, or metal to metal, or foam to wood etc., then epoxies take some beating, but they can be heavy, if over used and are expensive.
 
So I see no obvious issue with what you are planing on doing.
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Ken
 
You have just given me a fantastic idea for my need for speed,
now where did I see that cheap Wren turbine advertised...
 
..........Big Phil..............need for speed dept.............
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  • 2 months later...

Heres a link to a video I filmed of the Zagi the other day.

It was filmed using an 808 HD11# key fob camera attached to my cap.

Sorry about thew quality, I have a few gremlins to sort out.

Any way, as you can see I need more power!!!!

 

Phil

 

Ps

  I must fly closer to the camera

 

 

 

 

 

 

Edited By Big Phil on 26/03/2012 12:05:07

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  • 2 months later...

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