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My heli "store" has lots
of heli deals, useful
parts & other great
offers to help out
learner pilots...
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I thought it might be of interest to some of you to start to keep a
log of the rapidly growing number patients that are passing through
my heli-hospital scheme.
I will be trying to detail the damage found as well as
other information, so that perhaps a pattern will emerge of the
classic damage caused by "heavy" returns to earth.
| Type |
Power |
Cause |
Pilots skill level |
| Esky Belt CP V1 |
Electric |
Heavy landing |
Learning to hover |
This had pretty well all of the usual problems,
bent mainshaft, feathering shaft, blades damaged, tail shaft
bent, boom damaged, Flybar bent, Link on loop
connector on head broken.
|
| Esky Belt CP V1 |
Electric |
Heavy landing |
Learning to hover |
This had a lot of the usual milder problems,
feathering shaft, blades damaged, boom damaged.
|
| Esky Belt CP V2 |
Electric |
Crash in long grass |
Learning to hover |
Not too much damage due to the long grass, only
flybar and feathering shaft bent. However, basic
mechanical setup was utterly wrong, which probably caused
the crash.
|
| Century GL450 |
Electric |
Uncontrollable in
flight |
Expert |
| Only the feathering shaft was bent in this landing,
but the pilot was used to nitro helicopters, and this was
the first electric she had flown, and she found it to be
very nose heavy and too soft to be able to fly, especially
indoors, which was her plan.
I was asked to
investigate it's setup and correct it so that it would fly
as she expected. The major cause of the flight
characteristics described was the GL450 head design
itself. This has a rather weird setup which allows a
GREAT DEAL of TEETER on the head. The pilot finally
provided me with an Align 450 Clone head she had as a spare,
and after fitting that, the aircraft was totally
transformed.
|
| Hirobo Schweizer 300 |
Nitro |
Full build from HIROBO kit |
Expert |
This was a
commission to build the Schweizer 300 from scratch through
to test flying it. There is a build report of this
interesting build on this site - CLICK HERE
|
| Esky Belt CP V2 |
Electric |
Crash while on training skids |
Learning to hover |
Damage was caused by the stock plastic central hub
of the training gear breaking, causing the rods to jump up
into the path of the main rotors. The flybar and feathering
shaft were bent. Both blades wrecked, boom bent and
tail shaft bent. In this case the basic mechanical setup was
pretty good, apart
from the setup of the EK2 0407B HH gyro
which was way out.
|
| Esky Honey BEE King 2 |
Electric |
Crash while on training skids |
Learning to hover |
| Damage was caused by a sudden dive
to the ground from about 3 feet. The boom is bent, both
hiller mixer arms broke off at the connecting balls &
the mainshaft is slightly bent.
While
investigating the causes of the crash, I noticed that those
rather stupid bent wire 'S' connection on all the cyclic
servo horns really do allow & even promote far too much
free play at those most critical of points. Proper ball
connectors really should be used on all connections to the
swash plate, even on helicopters of this size.
|
| Esky Belt CP V2 |
Electric |
Mild Crash while training |
Learning to hover |
| This heli
didn't hit the ground very hard apparently, but one of the
aileron servos stripped it's teeth, the tail driven gear HAD
NO GEAR ON TOP AT ALL, flybar bent, feathering shaft bent,
and the general setup prior to strip down was
"poor". One rotor blade was a lot too tight, the
drive belt was far too loose, the lengths of connecting rods
to the swash were uneven and the swash was not even close to
level. |
| Esky Co-Commanche |
Electric |
Just would not fly |
Learning to hover |
| This was
virtually brand new, but flatly refused to come off the
ground. I stripped and lubricated it, fitted the extreme
longer inner shaft with locking top cap, "Bent"
the flybar to add efficiency in banking, and reset the swash
plate. Also added a full set of "indestructible"
rotor blades. Flies quite nicely now... |
| Esky Belt CP V2 |
Electric |
Would not fly |
Able to hover + circuits |
| This was
another virtually brand new Belt CP V2 helicopter that had been
involved in one light crash only, and the owner had replaced
the feathering shaft, which was the only apparent damage.
The whole helicopter felt far too tight, with no proper
movement of the main shaft or the blade grips.
Initial
checks showed a bunch of pretty normal issues - rear belt
tension wheel not able to rotate, belt too tight, swash
plate not level, COG wrong etc, but even after removing the
motor completely, and totally loosening the belt, the
mainshaft was still very tight to rotate.
Further
investigation showed that the one way bearing was half
seized, so we replaced it with a new Interceptor 400 main
gear and bearing. Reset the motor and adjusted the
tail belt which promptly tightened every thing back up
again, so I removed the tail gearbox and belt to find that it was of course
twisted twice. Corrected that and we had nice free
rotation again.
I then
checked the feathering shaft, as the blade grips were far to
hard to turn. I found various spurious washers in the
assembly that I removed, and then reassembled it correctly
and set the tension on the 2 5.5mm nyloc nuts to get the
grips moving just nicely, and a good pressure on the O
rings.
I then
went through the entire mechanical setup, gyro setup etc,
and we took her out for a test flight. All was pretty good,
but the tail still wanted a tiny bit more
adjustment.
The
final task was to strip the TX down and reset the throttle
trimmer correctly so that it was possible to get full
throttle, and to start to spool up before 50% stick.
The heli then flew very well again.
A
pretty typical Belt CP really, and one that everyone out
there should take note of , as it is a classic example
of what is wrong with Belt CP's - right out of the
box........
|
| Esky Belt CP V2 |
Electric |
Just would not lift off the ground |
Capable at hovering |
| This was
virtually brand new, but had just had a nasty crash that
only caused the rotor blades to be totally
"trashed", but after replacing those, the owner
found that it would not lift off at all, and made some
rather strange "slipping" noises.
The
crash was caused by a total loss of radio communication
(stock Esky Radio) and the heli landed upright, but then
turned on one side and "beat itself to death" on
the ground until the Lipo was disconnected
Further
examination showed that the Helimax 400 main gear, which had
only been fitted quite recently, was completely intact as
far as the teeth were concerned, which was quite a surprise,
and in fact the slipping was being caused by the entire one
way bearing housing rotating inside the nylon wheel.
Obviously,
the gear teeth had taken the power just fine, so well in
fact that it had forced the one way bearing to spin inside
the main gear, which caused the nylon to melt around it and
"squirt" out of the top end as molten nylon.
The
cure was simply to replace the main gear.
This
does illustrate very well just how strong these Helimax 400
gears really are.
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