Hi,

My first idea was to make a build thread of the plane like I did in the spanish forum AeromodelismoVirtual.com, but here the thread is long, and my english is not very fluid, and I´m so lazy....

But I´m receiving a lot of questions about the plane, so here I am

First of all, if you know spanish, go to the spanish thread. It´s my native language and probably I expained all much better there.

But if you don´t know spanish I´ll try to do my best here

The overall thought about the plane is that it´s not a plane for newbies because needs a lot of work to assemble like a FPV ship, needs a lot of adjusting to fly properly, and it´s soft foam (not elapor) with thin parts that make durability a weak point if you have some crash.

The strong points are it´s a pusher plane with its benefits, fits a 8 inches prop (with a little trimming) what gives good thrust for a pusher plane, has ailerons, has landing gear with steerable nose wheel, and has a lot of room to fit all the gear you want to fit.



The kit:

When I received the kit the first impresion was: "hey, it´s finished!" Even the horns and kwick links were attached, but once you start to look at the details.... OMG!!!

The glue used to join the fuse and plywood reinforcements is... I think a chewing gum would work better

By andres125sx at 2007-06-09

By andres125sx at 2007-05-27

If I´d have to buil another one probably would detach all I could to glue it with foam safe ciano, instead of gluing only the detached parts like I did.

The wing spar is a joke. There are two carbon spars joined with an aluminium pin at the middle of the wing, so the part that will handle the biggest efforts is a 2mm aluminium pin that obviously can´t handle the efforts. A guy here in RcGroups totalled his Busy Bee (not fpv) due to this pin


By andres125sx at 2007-06-09

I removed this one and glued a entire 4mm spar (used a solid one because the LHS didn´t have hollows spars, but it´s 10g more that I think is not neccessary)

In this pic you can also see the glass fiber tape I used to reinforce the aileron horns. They came loose or too tighten crushing the foam . I also replaced the hinges that were of paper and didn´t like them.

By andres125sx at 2007-05-27

One thing I liked was the molding work, it has no dots or mold marks, very smooth.

The tail (horizontal and vertical) are plastic laminated foam, I like it.

- Modifications:

I modified two things, the rubber bands to hold the wings didn´t like me (since my first rc plane 14 years ago I had forgotten this system ) and the motor mount.

To hold the wings I used some spare parts of my GWS planes for the front part, and a 4mm screw (I initially thought about using a nylon screw, but finally used a steel one) for the back, sitting in a plywood plate in the wing and screwed in a nut glued to a balsa block in the fuse, all glued with 5min epoxy.


By andres125sx at 2007-05-27

By andres125sx at 2007-05-27

By andres125sx at 2007-05-27


The motor mount must be reinforced if you have planned any setup above 100-150W. Mine is 220W and when I passed half motor the mount started to sake violently

I did two reinforcements with 1mm steel. It´s like a "L" girder to achieve good rigidity in both axis. Only with one I was able to hit WOT

By andres125sx at 2007-07-13

By andres125sx at 2007-07-13



I´ll continue after the nap

Originally Posted by AndrésMtnez

- Modifications:

The motor mount must be reinforced if you have planned any setup above 100-150W. Mine is 220W and when I passed half motor the mount started to sake violently

The "Shaking violently" part sounds more like a prop balance issue than the motor mount issue.

If a motor mount is not "sturdy enough" then it would simply fail and break, not shaking violently. Only prop out of balance/center would cause violent shaking at certain RPM range due to resonance.

The prop was balanced, but if the mount can be moved around 1cm to each side with a little effort with a finger then the result is not a fail or break, but a shake.

Like in real metalic structures calculation, the limiting factor is not the resistance, but the warp

Everything must have a fixed rigidity according to the efforts that is going to handle, and if you fit a motor with double the power of the stock motor then it´s normal the mount can´t handle it.


But thanks for the comment


Andres

Like you may see in the last pictures, I also replaced the wood screws of the mount with others with nut. A wood screw in a motor mount is an assured fail in the future IMO.


When a plane with ailerons uses one servo for both ailerons and it´s in the bottom of the wing, if you use a straight servo arm you have a mechanical differential in the wrong way (the ailerons would move more downwards than upwards). To solve this I used a servo arm with two arms at 90 degrees. With 45 degrees back each arm minus the angle of the aileron pushrods you have a little differential, less than what I thougt, but after the flight test it´s perfect

I didn´t want a big throw then I fixed the pushrods to the inner hole of the servo arm, but the kwick-link bump with the servo shaft. With metalic kwick-links and a dremmel it´s easily solved. If you watch the video I posted recorded in third person I think you´ll agree the rolls are almost perfect, much better than what I expected with this plane

- Fitting the equipment:

This is what I had planned


But the main battery was a hard fit under the wings with the esc and BEC. Also there would be three heat generators in a tight place, and didn´t like me. From the picture the only change was the two batteries that now I fix in the canopy at the back of the camera, and the 5v regulator and servostretcher, that I fixed to the pan/tilt mechanism to make it easier to change to another plane (I have planned a FPV glider too). Now all the fpv gear is in the pan/tilt mechanism, except the tx. To hold it in the plane I glued two pine sticks in the canopy floor after dremmeling the foam to make a hole and fit inside the sticks. They are around 14cm long to ensure they wont pull out the foam. With two screws it´s safe and fast to change.

With this layout the CG is a bit too forward for my taste, I like it around 70mm from the LE.

It look nice. But it's amazing everything you need to change, I hope it will not broke somewhere you did not expect

Well looks like Andreas did his homework and reinforced where is was needed with keeping the weight down at the same time

Love your plane.. truely!!! You did do major changes and seems to me you enjoy taking on challenges and making this whole project work successfully!

Denis: BTW I quite enjoyed how your SUPER DUDE moved his arms with the ailerons.... ok I'm jealous now

Originally Posted by VRflyer

It look nice. But it's amazing everything you need to change, I hope it will not broke somewhere you did not expect

Thanks Vrflyer

Yes it needed a lot of work, I´m not sure if I would have bought it if I had known all this before the purchase, it´s the problem of being the first, but now that it´s finished and adjusted I´m very happy with the BB

Originally Posted by JMSTECH

Well looks like Andreas did his homework and reinforced where is was needed with keeping the weight down at the same time

Love your plane.. truely!!! You did do major changes and seems to me you enjoy taking on challenges and making this whole project work successfully!

Denis: BTW I quite enjoyed how your SUPER DUDE moved his arms with the ailerons.... ok I'm jealous now

Thanks, but the next time I´ll ask you how to paint it before

This was a disaster, I have to improve my painting technique a lot, specially after seeing your EZ, that´s a nice job!


Andres

I had not mentioned the incidence problem that some people have had. BosTom had to raise 6mm the LE of the horizontal stab. Mine was 2 degrees off and didn´t change it, but when I modified the wing support maybe I corrected it



- Maiden flight:

I did the maiden before fitting the FPV gear to test and adjust it. The CG was located at 65-66mm and the motor incidence was like the motor seated in the mount. Both were wrong

The CG was too forward, and this caused an unestable behaviour at slow speed, fell down quickly and needed more runway to take off.

The motor incidence was adjusted three times to correct the dive tendency with motor on, but after this I ended up the easy way dialing two mixes with the rc tx.

This is my first pusher plane and I´ve noticed a big difference. When flying slow the tail does not receive the flow of the prop loosing some control. If you stall (tip stall does not exist, only loose altitude) will need more altitude to put the nose up. I think another difference is that when flying slow the angle of attack is high, but the motor is not pushing with the same angle since this configuration needs a much lower incidence for the motor, and then it´s pushing almost horizontaly and that doesn´t help to mantain a leveled and stable slow flight. This also causes you need more motor to perform slow turns, or will loose altitude. With a plane with the motor in the nose the motor incidence is much lower and with the same AOA the motor is pushing the plane more upwards, what helps a lot to fly really slow. But with only two clicks of the throttle stick over the minimum motor position where the plane can fly leveled this problem disapear. Probably the problem is that I like too much flying near the stall speed

Anyway this is the problem of a pusher plane, but the benefit it gives (perfect views for FPV) for me is more important than the "problem". I would change the views I have for nothing and once you get used to this behaviour it´s not critical or treacherous, indeed, I think it´s a realistic behaviour for a plane.

When I was adjusting the motor incidence and CG I had a crash due to another tx with my frecuency Fortunately there was no big damange (I expected a totalled plane ), but the tail bent a little. It´s soft and thin foam and is easy to bend. The problem is that this changes the tail incidence. I´d reinforce the tail with two 2mm carbon or wood rods to prevent this if I´d have to build another one.

Once all is adjusted the Busy Bee flys nice, if you don´t fly near the stall speed the stability is good (for a 1m foamy ), and it´s much more agile than what I expected. Roll rate is around 1 roll per second with the aileron linkage I did. The AUW is around 900g (32oz) and does not glide well, but it´s not the purpose of this plane. Flying inverted needs some elevator push to mantain it leveled, but can climb from inverted easily. An odd behaviour I found is that if you fly inverted at slow speed and push the elevator it perfoms a half loop that remind me to a heli flip, it turns over without climbing This must be caused by the motor incidence, that flying inverted is pushig the plane upwards and facilitate this turn.

I´ve just posted the last part of the Busy Bee video in the FPV videos thread, but I´m going to post the four videos I have here too.

Maiden flight in third person with the CG and motor incidence still not adjusted:

Estreno Busy Bee (5 min 52 sec)

Or to download with better quality:

http://www.fileflyer.com/view/ojxF2AM
or
http://www.megaupload.com/es/?d=ZKQ7PXPB



FPV first part:

Kinepolis 31julio07 p1 (4 min 32 sec)

To download it:

http://www.fileflyer.com/view/CJ9DgB4
or
http://www.megaupload.com/es/?d=QSMZX0N0



FPV second part:

Kinepolis 31julio07 p2 (3 min 22 sec)

To download:
http://www.fileflyer.com/view/wd2aiBb
or
http://www.megaupload.com/es/?d=4DCG0TNH



FPV third part:

Kinepolis 31julio07 p3 (5 min 39 sec)

To download:
http://www.fileflyer.com/view/kDO6dAg
or
http://www.megaupload.com/es/?d=QABQMDXE



Hope you enjoy them

Andres

Hey Andres...

I had to watch those videos again... love em! The last one has some really great city night shots! Really pleasant and relaxing! Keep up the great work!
Oh about how I painted the elapor styro foam, I should perhaps post some pictures of the products I used? I don't know only if people wanted to know.

Originally Posted by JMSTECH

Hey Andres...

I had to watch those videos again... love em! The last one has some really great city night shots! Really pleasant and relaxing! Keep up the great work!
Oh about how I painted the elapor styro foam, I should perhaps post some pictures of the products I used? I don't know only if people wanted to know.

sure post the pictures we do want to see them!


Damian

Thanks JMS

I´ve watched the last one around 20 times, my best one so far, love it