Depron Heinkel HE162

The launch was actually at half throttle. It is not easy to hold with its rather high thrust line.
As it sank to the ground I applied full power and it climbed vigorously but as soon as the motor stopped (you can hear it cut out) there was no control of anything!
It stalled and the nose dropped as the speed decayed and went into a right bank dive. No response from the ailerons or elevator. As soon as the nose started to lift I put on down elevator but it stalled again. The throttle was open the whole time.

Anyway the damage was fairly severe. The impact caused the wing bolts to pull out locally disrupting the fuselage. The complete engine nacelle partially broke away from the fuselage and of course the nose was quite severely disrupted. The wing itself only had very slight RH tip damage.
Repairs underway with the damage round the wing mount and nacelle stabilised with making tape and the glue drying.

The nose back to the canopy will have to be completely rebuilt.
The nose cut back and a new former "C" added.

Note the negative wire on the Deans. It was held in pace by the shrink wrap. :woohoo:
It would appear my first suspicion was correct.



.

At least you now know!

A start on the new nose section.
My usual vertical planking.

Seriously wobbly to start with and using up a bit of my scarce 2 mm rear Depron. :woohoo:

The nose planking complete and the new nose glued on.

Not perfect but adequate and with little or no weight gain.
The Battery Box is replaced onto the cockpit floor. The box also supports the OPTO ESC and SBEC.

The front half of the canopy surround is a slightly different shape so the "battery hatch" canopy will have to be partially rebuilt to give a good fit.

Nearly there!

At last video!

Unfortunately the camera did not like the very bright clouds so nearly 2 minutes had to edited out.
Actually it was its second flight as the camera did not work on the first. It needed a factory reset!
It does fly ridiculously slowly.
I suspect the CofG is still a touch aft and even with the oversize fins it has marginal lateral stability close to the stall. At the stall it drops a wing and then just sinks sideways. The only recovery is full power to get it moving forwards again. :woohoo:
Not very clear but you can see it start to do this in the video at 1:45

I agree.Judging by the way that loop tightened up dramaticaly after going 'over the top' and the flip-loop a bit later, where it appeared to be in a vertical dive at the trees - I'd say the c of g is too far back, but not by much.

As Eric said, "not by much" you should be really pleased with that Simon.

As the HE 162 now flies reasonably well I thought I would risk ruining it by removing the over size fins and putting back the original scale ones. :woohoo:
To compensate I have arranged that the battery in the nose can go forward by up to 30 mm which should help restore the directional stability.
At the same time I finished off its 'decoration'.



Something like correct but there was little commonality at the time.
Whether I dare fly it in front of an audience at a club is another matter.

Well that didn't go to well1

I fear the reduction in area from the scale fins significantly increased the directional problems which it had even on the previous successful flight coupled with a bout of significant wind and turbulence along with me struggling to keep the speed up sufficiently.
The wing tore out the mounting bolts, again, and crumpled a wing tip a bit more!
I have a sneaking suspicion it really needs working rudders controlled by the gyro.

Anyway to make up for the disappointment directly after the rain stopped the wind died away completely so I flew the all black Hunter F6 which behaved very nicely. The only issue is its 50 mm EDF whilst powerful and quiet doesn't half gobble up the juice. 3 minutes max and that's with a degree of throttle management. :woohoo:

Simon, that looked more like a CoG problem to me, very difficult to see.

The reason I am not sure it is a simple CofG problem as it is already at about 20% of the mean chord.
The thin line is the root balance point which is just 18.75% of the root chord.

The wing section is pretty conventional so providing the tail to wing incidence is not way out it should if anything fly a touch nose heavy.

In the video from 00:13 to 00:15 you can see the HE162 simply does not react to the influence of the fins indeed it is almost travelling sideways until it stalls nose high, drops almost to the vertical and recovers. :woohoo: Not really visible in the video but it repeats such a manoeuvre a couple more times.
My own feeling is due to the substantial fuselage area ahead and above the CofG beyond a certain yaw angle it becomes laterally unstable. I also suspect the relatively low exit velocity of a low powered EDF compared to a proper turbine means the airflow over the fins and tail plane is readily effected by any pitch and yaw of the plane. This is why I am considering means to add rudders so hopefully the gyro will prevent a severe yaw from developing.

I have been working how I might organise giving it working rudders.
The original had each rudder split top and bottom to clear the tail plane.

A complication I can do without!
The elevator stops short of the fin so with a cut out in the tail plane I can use a one piece rudder.
My idea is to mount a single bell crank at the centre of the tail plane on the tail cone and move the rudders with 2 mm carbon tube push rods.

The bell crank would be moved by long pull/pull lines from the 5g servo up front nearly 1.5 m away.:ohmy:
So a bit of printing.

A revised tail cone which includes a mounting for the printed bell crank. Made as light as possible simply because any weight added is at the extreme rear. It should be countered by the servo that will be placed well ahead of the CofG.
Hopefully the complete rudder installation will only add about 12g.
Actual fitting will have wait until the carbon tubes arrive.

After several attempts I have fitted the the bell crank and 2mm carbon push rod to the left hand rudder which is now a single unit.

It all seems to work ad is very free running which just as well as it is a small servo.
Now to do the same on the other side and then mount the servo up front, 1.1 m away! :woohoo:

A short video of the rudders working on the He 162.

Not entirely happy with it so revision no.3!

The Mk2 rudder linkage with a longer arm bell crank.

The longer arm better matches the travel of the rudders and puts the nylon monofilament under less load.
The rudder servo mounted in the top of the fuselage just behind the cockpit.

The servo has a printed arm extension to match the longer arms of the bell crank.

It is a 'click' fit over the existing servo arm so needs no glue.
There are two sets of guides between the servo and the bell crank to ensure the lines are kept well above the wing so it does not interfere with its installation and removal.
One advantage of mono filament line apart from being cheap is that unless you get the light angle correct it is really quite hard to see.