[wingtipper]

Mate im no designer but i think the 1st pic without the flares might be ok . As smuzz pointed out previously it is a short rudder . Try it 1st then add the balsa flare and try it again . My bet is it will fly better without . And if it drags reduce the rudder length

[secant0give]

Mate im no designer but i think the 1st pic without the flares might be ok . As smuzz pointed out previously it is a short rudder . Try it 1st then add the balsa flare and try it again . My bet is it will fly better without . And if it drags reduce the rudder length

Too late for testing with out fairings now,

The fairing are in place the plane has been balanced and it's ready for a test flight.

Adding the fairings won't decrease the effectiveness of the verticle fin, Which is what I think you mean to say, as this plane doesn't have a rudder.

The verticle fin is no bigger than it was before but it has been moved back this will facilitate the desired change, which is, moving the center of lateral area further aft. You've got to remember that it's not just the size of the fin that matters, it's the area on the side of the fuse too, and it matters how far back that area is in relation to the C of G.

When there is too much lateral area too far forward then then forces are generated that want to make the plane fly sideways, So it Yaws. If the geometry is bad enough the act of yawing generates even more yawing force and things get really out of hand.

Putting the fairing on doesn't change the lateral area. It will reduce drag tho' and it should cause the air to flow around the fuse/fin junction rather than up the ramp that Kizza pointed out.

The sugestion was that the ramp might cause a pitching moment and that was to my mind a greater concern than the extra drag. Although the fairing should in some way improve both.

Of course it's all academic untill it's tested and even then it's sketchy because you have to repeat things many times to prove something for certain. I don't want a repeat of the first flight ever again let alone many times

I might get in that test flight this arvo if things go well

---

After watching the video quite a few more times. I can see that the plane leaves my had pretty straight and with the wings level. Just after it leaves my hand it Yaws hard to the right and then begins to roll to the right. Jag corrects the roll with ailerons and then it Yaws the other way, this time much harder, it also has the torque working with it on this side, it goes spinning off totally out of controll.
If you watch it closely you can see the tail go out as tho it was given a heap of right rudder just after it was launched, then it swings the other way initiating the spin.

[wingtipper]

well the mark 2 version , was an extreme success . wait till you see the video of this thing. 270km/hr +( tick) ,able to withstand 50g's ( tick) , slippery ( tick) stable ( tick) hand launchable at 1/2 throttle with ease and no torque roll ( tick) landing speed of a trainer ( tick) . wait till you see the video of this little piece of dynamite .

[smuzz]

Yeh - I stopped off at the field on the way to get some State of Origin "supplies", because I could hear the testing going on from my place.

I was shocked at how it could be transformed from diabolically bad stability/controllability into a top-notch machine at all ends of the flight envelope with just the one modification! I've had a few lessons in aerodynamics since getting back into this hobby, but that one was remarkable!

Nice work Kizza for making an accurate diagnosis - and to Secant0give for so rapidly getting it all tweaked

[Flying fisho]

So pleased you have got all the quirks out of this labour of love. A happy ending is what we all dream of. Congratulations on a remarkable effort. Hope my earlier attempt at humour was not received with any ill feelings. I obvously am not design savvy & had no idea of how to fix your problem. Was just trying to help raise the sprits after a disasterous result of much effort.

[secant0give]

Well it worked !!
I'm just uploading the edited video to you tube.
For some reason it takes hours and hours to upload just 5 mins of video ????
I guess it is in HD and the file size is about 1/2 a gig but it is in the preferred format .mov

Anyway enough winging about my internet connection's upload speed.
IT FLIES !!! not only does it fly , it flies really well.

It turned superbly well at full speed and handled great at low low speed as well, with no sign of having a nasty stall despite having a wing loading of nearly 20 oz per sq ft.
Which I think is reasonably heavy for a model that size. It’s not much bigger than a rare bear. I ended up having three flights with it yesterday evening before we ran out of light. I can say that in no uncertain terms it does fairly shift along!!

I havn't done a Doppler shift analysis on any of the video yet so I'm reluctant to comment on the speed but I can safely say that it's the fastest thing I've ever flown by some margin.

I'm inspired now I'm going to keep the same moments and dimensions and clean up the shape of the back of the fuse in the form of a plug. Then I can make a set of moulds for a glass fuse and hatches.

The 3000 Kv motor 4.5 X 4.5 prop and the nano tech 4S 1300 lipo pack are near perfect match allowing for just under 2 mins of flat out flying with enough left to get around slowly for a bit, before landing

Here's some video

http://www.youtube.com/watch?v=ZXWtJh4Szmo

---

So pleased you have got all the quirks out of this labour of love. A happy ending is what we all dream of. Congratulations on a remarkable effort. Hope my earlier attempt at humour was not received with any ill feelings. I obvously am not design savvy & had no idea of how to fix your problem. Was just trying to help raise the sprits after a disasterous result of much effort.

Thanks Wayne, I quite enjoyed your earlier comment even tho I didn't quite understand the science behind it

The earlier crash was a bit a bit of a low point I must say after quite a bit of effort had gone into, not just building the model, but photographing it at various stages and writing it up.

I was super glad Claudio filmed the first flight and super glad that Jag was flying it too. It gave me the opportunity to have a number of very smart people have a look at what happened. And paved the way for the final successful result. A big thank you to Kieran for his input and to Doug Owen who also looked at the video and emailed me back arriving at a very similar diagnosis to Kieran's. Many thanks to everyone who commented and provided advice. I appreciate it all very much.

[wingtipper]

mate thanks for posting that . thats one very fast plane . !!!!!

[gbanger]

Absolutely stoked that it flies so well Jason... it does sound very noisy though mate... Will have to do a db test on the little sucker on the weekend... hope it is under so you can continue to enjoy that speed.
One of the points on tonights agenda at the committee meeting was the increasing noise levels from aircraft down at the field.... we will be clamping down on noisy models over the next few months.

[secant0give]

It is noisy with that prop but not way over the top. I've got a couple of Graupners on order
That should quiet it down a bit.

[gbanger]

I wasn't having a dig mate... just using your noisy little plane to make a point to all the other members.

[secant0give]

I wasn't having a dig mate... just using your noisy little plane to make a point to all the other members.

Gazz I fully understand and I agree we can't have noise complaints.
We have never had any before and we want to keep it that way.

The Dynamite will need some need some improvement in that area. It's all part of the development process.

There are a lot of things that can be done to reduce noise, In fact it takes quite a bit of power to make noise and that power is always better used creating thrust rather than sound energy.

A better prop and careful balancing will help, I havn't done that to the dynamite's yet.

Another thing that you might find surprising, and it surprised me, that potting the windings reduces noise a lot. It made a very noticeable difference to my RareBear, After potting with 5 min epoxy it about halved the sound it makes. Not that they are overly loud but there was a very noticeable reduction in sound. I aslo did the G160 in my big HK yak 55m and that stopped a lot of the crazy noises coming from that.

Another option is to go for a lower KV motor and use a bigger prop. We've seen Samste get good results by doing that with some of his speedsters.

[secant0give]

Well It passed the sound level test today measuring just 78.6 Db Quite a bit short of the allowed 80, since an increase of 3dB equals about double the sound energy.

It's early days yet and there's still room for improvement, I'm sure I can reduce that quite a bit more.

[secant0give]

Here's a short clip from the flight Frank R filmed for me yesterday.

I was able to get a decent Doppler shift speed measurement from it.

It also show's just how tight this little thing will turn at speed. I slowed the pass down a bit and tacked it on the end, it certainly is manoeuvrable at speed.

I did tame the elevator back by reducing the rates a bit more and increasing the expo a bit more as well

Dr Martin Hepperle really did design a sweet airfoil section for us

http://www.youtube.com/watch?v=-YySKZ1Li-0

[wingtipper]

Awesome stuff

[secant0give]

Here's the rest of the video Frank R took from Yesterday

http://www.youtube.com/watch?v=keRcYI8HcrU&feature=youtu.be

and here in HD

https://www.youtube.com/watch?v=FYhTZ5LTefo

[secant0give]

Work has started on a plug for a fuse mould.
It's mad from Sugger pine, mainly because I had a nice peice laying around and it's very nice timber to work with.
Balsa would probably have been better but beggers can't be choosers
   

[samste]

Work has started on a plug for a fuse mould.
It's mad from Sugger pine, mainly because I had a nice peice laying around and it's very nice timber to work with.
Balsa would probably have been better but beggers can't be choosers

Nice, are you going to do a dip type method or brush glass and slide out ?

[secant0give]

I'll make the mould in two halves, from the inside out it will be as follows:

Gelcoat then strong bog in the sharp corners then 2 oz cloth, then 4 or 5 layers of 6 oz cloth, then I'll back that up with 2 layers of heavy Bi-axial glass cloth and I'll make a few frames from 1/2 plywood to hold it all nice and stiff.

Once the mould is made it should be very quick to knock out a fuse or 2 or 4.

I think it's worthwhile making a mould of this one, it's just such a lovely flyer. It handles beautifully despite being reasonably heavy for it it's size.

It doesn't have to be built that heavy either
With a Rarebare motor in it and the 1300 4S pack it would be quite a bit lighter than it is now. It would fly for ages and still be quicker than a rarebear. Being lighter I'm sure it would fly even nicer as well.

There are also some in-runners that might go very well too running 3S lipos.

There is heaps of room in the fuse to take any number of different configurations of motor esc and lipo pack.

I was actually supprised at how quick and easy it was to rough out the shape of the plug. Much quicker than building up a fuse from Balsa sheets
Here's the plug with a little more work done to it. I've probably spent a little over an hour on it so far.

   

[smuzz]

I like the vernier calipers positioned in the photograph mate - certainly lends an air of precision engineering

[secant0give]

I like the vernier calipers positioned in the photograph mate - certainly lends an air of precision engineering

Love my Mitutoyos cant be with out them, would you believe it's my third set.
I've worn out too other sets, literally, the slide gets loose in the middle and tight at the ends after a while, They say a good set of callipers should last a life time, but when you use them dozens of times a day for years they do wear out. This last pair are still pretty good tho

[samste]

I will place an order for 1 plane please
I have plenty of high powered setups that i could put in it.
Steve

[secant0give]

No probs Steve, I'll crank up the sausage machine again tomorrow

[secant0give]

A bit more tinkering with the plug early this morning

Aligning the fuse to machine the incedence of the tail at zero to the cord line of the wing. The thrust angle (front end of the fuse) and the gap for the elevator servo hatch were all machined in the same set up. All zero, zero like the prototype. Although the thrust angle can be adjusted easily enough in the finished model, if you wanted too.

   

Here's the modified first fuse, the new plug with the section for the front hatch cut out, and other fuse in it original configureation

   

[secant0give]

Wing fairings have been fitted to the fuse and it's ready for a little filler a light sand and some sealer/primer

   

[secant0give]

A few laps around the mulbery bush,

Paint fill sand, paint fill sand, paint fill sand, paint fill sand,


Paint fill sand, paint fill sand, paint fill sand, paint fill sand,

   

[secant0give]

It's no good useing abrasive paper on the end of your finger 'cause you just end up carving a groove in what ever your working on.

Here's some picks showing the polishing sticks I used to sand into awkward the corners and hard to get at shapes.

I've just cut a sheet of 400 grit into strips and work away with them wrapped around the end of the stick. It's good to move the paper allong and expose a fresh section the moment it becomes loaded.

   

   

More paint ready for the nest round of paint fill sand....paint fill sand...paint fill sand................

   

[wingtipper]

nice work mate

[secant0give]

Thanks 'tipper !!

Here's the plug for the motor/ESC access hatch, it's bonded on to it's parting board ready for another coat of primer.

   

[secant0give]

Last coat of paint !!.............. Few........
It's not a perfect finish but it should make a nice mould.

After pulling the plug out of the mould any blemishes will be little pips sticking up instead of being little hollows like in the core. These should be easily sanded off the surface of the mould with 800 grit paper if need be.

Here's a pic if the plugs with the top coat on. I'll let this harden for a week I think before I try to take a mould off them.

   

   

And here is the board that will for the part line of the mould. I've marked it out just by tracing roughly around the plug. Then I'm going to drill a hole through to get a saw blade in and cut out the shape.
I'm also going to fit a couple of Pins to the parting board to make sure that both halves of the mould line up spot on every time they are put together.

   

[secant0give]

A bit more done, some aluminum pins to line things up. The parting board is all cut out ready for the plug when the paint hardens a bit more.

   

---

The moulded glass fairings for the servos and the controll rods cut to size, made to fit and bonded on with thick CA, touched off with Kicker before it could run off and do any mischeif.