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CriCri MC-15 in NZ

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MadRocketScientist

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May 16, 2009
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Canterbury, New Zealand, Earth, Milky Way Galaxy.
Hi Shannon
I have just purchased a set of original plans. Are you in the business of licensing or selling a copy of the CAD drawings you put together?
Thanks
Nick
nickjrowley@googlemail.com
Hi Nick,

Glad to hear you got a set! I am not going to release my CAD drawings at this stage. I have posted some of them on this thread. Mainly the parts that needed changing slightly.
 

MadRocketScientist

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Canterbury, New Zealand, Earth, Milky Way Galaxy.
How does that work in reality ?
The trim lever is attached to the elevator system by elastic bands so when the trim is moved it puts pressure on the stick fore and aft. The elastic is in the system to provide artificial stick forces at low speeds. With the all flying elevator the stick forces are so light it is easy to over-stress the air frame.
 

Speedboat100

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Nov 8, 2018
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The trim lever is attached to the elevator system by elastic bands so when the trim is moved it puts pressure on the stick fore and aft. The elastic is in the system to provide artificial stick forces at low speeds. With the all flying elevator the stick forces are so light it is easy to over-stress the air frame.

Any pictures to share of it ?

------

Here on the right ?


 
Last edited:

MadRocketScientist

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May 16, 2009
Messages
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Canterbury, New Zealand, Earth, Milky Way Galaxy.
Any pictures to share of it ?

------

Here on the right ?


How about a screenshot from the plans ;) Section B-B is on the side of the fuselage, the stick is in the center on a common tube.
CriCri trim setup.PNG
 

Vigilant1

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Ahh, the old days.... when Heinz and Colomban were still on speaking terms.

I bet you got a chuckle out of the "500-600 hour construction time." Maybe the kit was very complete.

Thanks for the article, it is an interesting read.
 

MadRocketScientist

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Canterbury, New Zealand, Earth, Milky Way Galaxy.
Back then you could d a lot in 500 - 600 hrs with tools and a set of paper drawings.No computers or internet.
I think the 5-600 hours was always a little bit optimistic for the CriCri. Later articles seem to state around 1000 hours, which seems more reasonable for a build exactly to plans. It isn't really a quick aircraft to build by any stretch of the imagination. Simpler aircraft such as the hummelbird should be able to be completed in much shorter time.
 

MadRocketScientist

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May 16, 2009
Messages
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Location
Canterbury, New Zealand, Earth, Milky Way Galaxy.
While searching for details on how the MC-100 tailplane was removed for trailering, I came across an interesting elevator pivot failure on a MCR-01 Banbi. While this doesn't apply directly to the CriCri and there are no reported failures of the plans built CriCri elevator, it does give pause for thought since the CriCri elevator pivots are mounted the same way.

One MCR-01 had a complete loss of the horizontal tailplane in flight. (first link below) Incredibly both occupants survived the uncontrolled crash into trees but with serious injuries. The cause of the failure was attributed to stress corrosion in the aluminium elevator brackets holding the spherical bearings. The replacement pivots were manufactured from stainless steel and the bearings glued into place rather than a press fit and staking. There seems to have been no further problems with these new parts. Also of interest is that the pivots were the same thickness as the ones on the CriCri but on a two place aircraft with its higher flight loads.

The second failure was detected in the hanger as one of the pivot attachments on the fin had cracked and allowed the elevator to move slightly but was caught before it failed completely in flight. This is also attributed to stress corrosion cracking from the elevator pivot bolt being over tightened along with no corrosion protection coating or paint on the bracket itself. In response the LAA in the UK were looking at changing the inspection schedule for the MCR-01 that required the wings and tailplane to be removed every 3 years to inspect the metal attachment points for signs of corrosion.

As far as I can tell there have been no failures of this type on a CriCri, however it does show that good corrosion protection and care is needed when inspecting these parts. I found it interesting and I hope someone else might too. I still haven't found out how the tailplane is removed for transport on the MC-100:rolleyes:

Links here ⬇ and I have attached the .pdf files themselves as internet links are notorious for going AWOL.
 

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Speedboat100

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They are pivoted near to above the center of lift. The flutter in the zenair Cricket occurred due to the much too flexable flapperon link tube and then only because the flapperons work against each other, once one side is no longer connected the flutter stops.

Screen capture from the plans..⬇

Flex is no good in flight control arms.
 
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