I was quite impressed by the looks of this model and thought to build one. I
leant that pattern planes should be build with precision so this build will be
using more balsa wood and an almost equal proportion of Coro. There were quite
some differences from the original black magic plane so, I took the liberty of
naming the plane as ZEUS.
Specs:
Fuse length (Spinner to Rudder tip) - 50 to 54 inch
Wing span - Same as Fuse length
Power - OS 108 FSR (Over powered??)
Prop - 15 x 6 (I am not sure if this will be fine for the engine, but bench
testing shows that its is fine.. any suggestions appreciated.)
I have completed 70% of the fuse. The pics show the progress made till date.
Will update as a when I make progress. Since I work only on weekends, please
don't expect the plane to be complete in the next 2 - 3 months.
Thanks,
Ismail
Original Black Magic aircraft developed by Mike
Hester
June 30, 2008
The targeted weight break up as follows:
Fuse (without engine) - 1.5 Kg (right now it is at 800gms)
Wing with the joiners - 1 Kg
Engine with muffler - 0.8 Kg
The overall target is to keep the AUW under 3.5Kg. I have not calculated the
wing area/loading yet. I may increase the wing area such that I get the wing
loading appropriate for pattern type plane.
BTW, this week's update
1, Reinforced the tail section.
2, Installed the rudder servo and the pull-pull setup... (pull-pull setup is
such a PIA!)
The pics will say it all...
July 01, 2008
Updates on the build....
1, Installed the elevator servo. - Same pull-pull linkages which need to be
changed later on
2, Installed the turtle deck
3, Cutout the wing panels
4, Trial fitted the wing to the fuse - This may not be the final config. Will
undergo some more modifications.
Pics attached.
July 06, 2008
Ok folks... this weeks (minor) update.
Well, after a lot of head scratching I figured out a way to mount the wings. I
hope it would be reliable, sturdy and durable. Only time would tell how it
performs.
As I said in my earlier post, I will be using a alum tube for the wing joiner.
This tube will slide into the pvc tubes in the wings. Now, I have decided to
replace the pvc tube in the wing with fiber glass tube. I made the fiber glass
tube out of glass fabric and epoxy. Its quite strong and very light compared to
pvc.
Then, I made a failed attempt to make a fiber glass cowl for the engine. The
mistake I did is to use acetone for thinning the epoxy and apply it over a
thermocol die... I knew that acetone would eat up the thermocol... but it struck
my mind just after I finished applying it. It was too late and by then acetone
has already started attacking the foam.
Now for the pics...
July 13, 2008
Here is this week's update:
1, Finished the wing construction - Servos are yet to be mounted
2, Reinforced the landing gear region in the fuse.
Pics will tell it all...
July 20, 2008
This week there not much progress as I had other stuff to do. Whatever time I
spent on this model is more on planning rather than building.
So, here are the things done this week:
1, Braces for the tail feathers.
2, Wing attachment on the fuse. (This took a lot of time!)
3, Changed the ball link in the engine to the usual clevise mechanism.
4, Made the power module. (This is the engine with the throttle servo mounted on
the cutting board)
5, Bench tested the engine.
Well, after bench testing, I am a bit skeptical to use this 1.08 size on this
model. The vibration seems to be quite high. May be I should balance the prop
properly or better change to an new one. I will try this engine one more time
mounted in the model and see if the structure holds the vibrations. If not I
should change the engine to 60 size. (I have a super tiger 60 waiting for that -
just another power module)
July 24, 2008
I got some time work on the Zeus yesterday. I could finish the wing mount to
the fuselage. However, I am yet to figure out a mechanism to retain the wings to
the fuse. Ideas please...
BTW, the current weight of the model is about 3Kg. I guess after all the
finishing it would be about 3.5Kg.. which is about 21oz/sqin wing loading. I
would prefer a wing loading of 15-18oz/sqin... So, I am seriously thinking of
using a 60 size engine for this one... May be I will give this engine a try and
see how it performs with the extra power.
July 27, 2008
This week's update:
1, Wing servos mounted
2, Wiring for all the servos done. (Extensions required for all servos)
3, On board glow driver - Circuit from the net
4, Battery pack out of 4 GP 1600mA NiMH cells
5, Landing gear brace
August 12, 2008
Things done:
1, Covered the fuse
2, Installed the electronics.
3, Installed the fuel tank and the engine
4, Some stickering work done
Pics attached.
The AUW at this point is exactly at 3.5Kg. But I think this will increase as it
needs more nose weight (It will weight like a pig - May be a flying pig..). I
have ordered a 4.5 inch Alum spinner. Once I install it I will do the maiden.
With the increase in weight, I kind of reduced my expectation on the performance
of this plane.
August 16, 2008
I did the maiden today. I am glad that everything went well,
except for some minor mishaps.
The first two flights were short. Need to bring here down for engine tuning and
some CG adjustment. In both these landings I bent the landing gear wires. The
thin landing gear wires are not for this plane. On third flight, I tuned up the
engine properly and added some nose weight. I then had a nice flight. I will put
up this video shortly. On the fifth flight, I had a dead stick and made a hard
landing. Broke the tail wheel and again twisted the main gear. Its a simple fix
though.
As said earlier, the plane is tail heavy and with the huge power source at its
nose it starts to climb as soon as I open up the throttle. I am thinking of
using a good 60 size engine and extend the nose far out for correct CG. But this
will not happen in near future.
On a scale of 10, I would rate this plane about 6.5 to 7.
Positives:
1, Very sensitive on all the controls
2, Good vertical climb
3, Very less rudder input for Knife edges
4, Good at Split-S, Immelemans, loops etc. - Just the basic aerobatic stuff
never tried anything extraordinary.
Negatives:
1, Without engine power its a falling rock / Too heavy - @ ~3.7Kgs
2, Extremely Weak landing gear - Need to replace it
BTW, I have corogamied an engine cowl. Some pictures attached. Will post the
video shortly.
Here is the maiden flight video
If you have any questions or suggestions please contact me on
ismail -at- chenpro.com
