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Ultralights

Savannah 1000hr inspection notes.

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A lot of people have died in Landcruisers over the years simply because the chassis transfers the load onto the occupants, machines are stronger than people.

 

 

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Ever seen a forklift bounce? You wouldn't want to be strapped to it. I'm a great believer in crumple zones and all parts of the vehicle body designed for what it might encounter. In modern times you shouldn't expect less. Try driving an original military JEEP on a rough road. Nev

 

 

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good point on the seat belt attach points, maybe the trick would be to use a softer metal to add a little strength, something that will give a bit before deforming and breaking, acting as a crumple zone, but adding enough strength to prevent complete failure before the forces have dissipated completely

 

With the hinge pin bolt, is it a standard bolt in there? with a plate riveted over it? in not getting much idea from the construction manual..

 

image-L.jpg

 

 

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It is a standard AN bolt welded through a hole in the flat steel plate with the seven holes drilled in it to match the holes in the end rib, you could grind the welds and reuse the plate once you get it out, as mark said you will need to open the skin to get it out though just as you have to when you stuff up and put the long bolt plate on the wrong side.

 

 

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good point on the seat belt attach points, maybe the trick would be to use a softer metal to add a little strength, something that will give a bit before deforming and breaking, acting as a crumple zone, but adding enough strength to prevent complete failure before the forces have dissipated completely

With the hinge pin bolt, is it a standard bolt in there? with a plate riveted over it? in not getting much idea from the construction manual..

 

image-L.jpg

Interesting, on the 701 the hinge plate is a welded assembly but riveted on the outside of the end rib. Instead of a bolt it's a drilled rod.

 

 

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You too Steve? hahahahha we must be twins

I hadn't rivetted, only clecoed, when I checked! It happens becauces you sit it on the bench with the mounts sticking upwards, opposite to how it mounts on the fuselage. I did it once before at Reg's too, and he corrected me when he did the pre-rivetting check.

 

 

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Rob, I had my head in a CH 701 belly the other day and I noticed two alum straps abut 1.5" wide that run back ino the tail directly from the seatbelt shoulder strap attach points.This simple mod may be worth considering as I noticed on a crashed Savannah Bingo that these belt attach points had been severely stressed.

 

Obviously they had done their job ( both occupants survived the high impact nose down crash) however any Xtra strength here could be a good idea........

Maj, this 1.5" strap in the Zenith. Does Zenith just use 1.5" wide aircraft aluminium, i.e., the same thickness as the skin on the fuselage for this? How far back into the tail did these straps go?

 

And on the subject of the solid rod throttle linkages....in this same crash which had severe frontal crushing, the throttle rods were pushed back into the occupants chests breaking ribs in both. The large circular knob on the throttles should always be used as otherwise chest puncture wounds could have been the result..................Maj.....

That's good information Maj. Those large knobs are really essential!

 

Great feedback. Are there any other lessons from this event that you think we should know about ...and can learn from?

 

 

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Is welding an AN bolt an acceptable practice? I wouldn't have thought so. Nev

I would not have thought so either!

 

 

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Is welding an AN bolt an acceptable practice? I wouldn't have thought so. Nev

Factory performed and approved, welded to the same standard locally should be just dandy for a 19 rego! These bolts aslo are a mounted threaded pivot point not a bolt used under tension if that eases your mind.

 

 

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No it doesn't ease my mind at all, actually. I'm concerned about a heat treated item being welded. The factory MIGHT do the right thing but the principle is dangerous. Nev

 

 

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Is welding an AN bolt an acceptable practice? I wouldn't have thought so. Nev

An AN bolt ceases to be an AN bolt if it's exposed to welding heat; it becomes a piece of Cr-Mo alloy steel whose ultimate tensile strength will be around 80 KSI (instead of 125 KSI minimum). Provided the designer recognised this change in the tensile strength, there's nothing wrong in principle with using an AN bolt as the starting point - tho breathing the cadmium fumes from burning off the cad. plating may not be good for the welder . . .

 

The danger with welding Cr-Mo steels lies mainly in the consequences of fast-cooling them; they must be slow-cooled to avoid embrittlement. They end up in what metallurgists call the "Normalised" condition, if the welder knows what he is about.

 

 

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e

 

Maj, this 1.5" strap in the Zenith. Does Zenith just use 1.5" wide aircraft aluminium, i.e., the same thickness as the skin on the fuselage for this? How far back into the tail did these straps go?

 

 

 

That's good information Maj. Those large knobs are really essential!

 

Great feedback. Are there any other lessons from this event that you think we should know about ...and can learn from?

Knts.....I think they went back maybe a meter...... And thicker alum than the skin maybe .065 " at least...seem to be attached to the sides...next time I'll take some photos.............I've also seen some aircraft use cables to achieve the same thing, I think the Highlander has that. As far as the throttle knobs go, yes when you see those stainless throttle shafts protruding half a meter out of the dash...post - crash ....they do make sense ..Maj.....

 

 

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Knts.....I think they went back maybe a meter...... And thicker alum than the skin maybe .065 " at least...seem to be attached to the sides...next time I'll take some photos.............I've also seen some aircraft use cables to achieve the same thing, I think the Highlander has that. As far as the throttle knobs go, yes when you see those stainless throttle shafts protruding half a meter out of the dash...post - crash ....they do make sense ..Maj.....

Maj, do you know if this was a Zenith plan addition (it's certainly not in the 2006 version) or an "unofficial" mod?

 

 

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Just finished with the Elevator, and noticed something that could be considered important....

 

The Bolt connecting the trim tab pushrod to the servo motor has worn significantly

 

image-L.jpg

 

the bolt is located here (new bolt ready for re-installation)

 

image-L.jpg

 

image-L.jpg

 

i am thinking of making a small busing to go here to prevent prevent thurther wear into the bolt/screw.

 

 

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You could easily do that, then you could tighten the bolt against the shoulder and it wouldn't work around as much in use. Slightly chamfer the ends so they don't burr. (But you know that already). You are doing a thorough job. You could overhaul my aircraft anytime. Nev

 

 

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Just finished with the Elevator, and noticed something that could be considered important....The Bolt connecting the trim tab pushrod to the servo motor has worn significantly

 

image-L.jpg

 

the bolt is located here (new bolt ready for re-installation)

 

image-L.jpg

 

image-L.jpg

 

i am thinking of making a small busing to go here to prevent prevent thurther wear into the bolt/screw.

Trim tab bolts (usually 3/16 " bolts) wear pretty good on many types, the Cessna Caravan ones are pretty good at it. I'Ve got a theory that things vibrate pretty good back there without transmitting it back to the the controls....

 

 

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Into the home stretch now, i know its been almost 12 months, but i am only working on it about 1 day a week... anyways, finally got the repaint completed.. just a few touch up spots left to do with a small brush around rivets etc. and a few treated corrosion spots around joins.

 

also, its new wheels are installed.

 

10929161_10152994207044754_7173749782568049780_n.jpg?oh=33dea879f4df0d6009901b2ea4b8745a&oe=555207CE&__gda__=1432828843_d29232f33612604426a3067558333a88

 

All thats left to do now is finish the panel (2 ipads 1 MGL extreme EFIS, Transponder and radio), install the transponder encoder, the 3 AHARS units for the ipads and MGL and fuel flow meter, then the last mod is the duplication of the throttle cable to be straight on the right hand carby. then its new weight and balance calculations, fuel calibration, and dynamic prop balance. and then another 100Hrly as its been 12 months since its last flight.... fingers crossed its next flight will only be a few months away..

 

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now to get it in the sun for some proper pictures, and wash off whats left of 12 months of hangar dust

 

 

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Looking good ultralights:thumb up:

 

Love the paint job.

 

Also looks like a fine array of toys in that hangar:thumb up: From floats to red bull:yes:

 

 

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