CriCri MC-15 in NZ

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Kenneth Higdon

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Apr 12, 2020
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Shannon -
What is the advantages over the 3W engine. Weight, HP, rpm, cost, dependability ?

Kenneth Higdon - Alabama Beach builder
 

MadRocketScientist

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May 16, 2009
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Canterbury, New Zealand, Earth, Milky Way Galaxy.
Shannon -
What is the advantages over the 3W engine. Weight, HP, rpm, cost, dependability ?

Kenneth Higdon - Alabama Beach builder
Hi Kenneth, I am assuming you mean compared to the ZDZ210/250?

The ZDZ is around half the cost of a similar 3W engine. A plus for 3W is that many of the 3W engines have dual sparkplug heads. What sold it for me though was that the RC pylon racers were running the ZDZ210's at 9000rpm and 40+hp on methanol and they hold together just fine, ground impacts aside. There have been also some issues with the 3W crankshafts and prop hubs in the past, quite a few failures talked about over at the Flying Giants forum. I had a good hunt around the internet for failures in the ZDZ210's and didn't really come up with much, there are a few that got overheated and seized but that is an installation/operation issue. Good CHT and EGT will help stop a lot of overheating/ lean run issues.

Do you have any progress pictures? Feel free to poet some here!:cool:
Shannon.
 

proppastie

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NJ
but I have plenty of 1/16" stainless steel cable.
do you recommend 7x19 or 7x7 I can mill spec. with extra lubrication from Mcmaster...choices choices.....helps to get other opinions. Do you need end caps, Boden cable do not have them.
 

MadRocketScientist

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do you recommend 7x19 or 7x7 I can mill spec. with extra lubrication from Mcmaster...choices choices.....helps to get other opinions. Do you need end caps, Boden cable do not have them.
I think all the 1/16 cable I have is 7x7, in that small cable the strand size for 7x19 is pretty thin! Some of my 1/16 cable is generic bycycle cable and some is aircraft cable.
 

MadRocketScientist

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Canterbury, New Zealand, Earth, Milky Way Galaxy.
Another 'little' job almost sorted, this one took me all afternoon and its still not finished!

I dug out the canopy latches and after checking that they worked okay I took them apart and gave them a good working over with the scotchbrite pad. When I was happy with the finish I alodined them.
I was thinking of painting these red all over but the other day in the shower I had the idea to paint the insides red and the outside white to match the other control knobs. The red should be easily visible to see when they are unlatched.
DSC09557 (Medium).JPGDSC09559 (Medium).JPGDSC09561 (Medium).JPG
I masked off the outsides and painted the red on. Once that was dry I masked out the inside and painted on the white. I painted the top coat directly over the alodine finish and some of the red paint still lifted in places. I tried leaving the paint a while and letting it bake in the sun but it didn't seem to help. Maybe I should have used primer.
I needed to remake some of the pivot pins as the previous ones I made were a little too short. They were quite quick to make in the lathe. I peened over one end before putting the pins in the latches. I will let the paint harden up some more before peening over the other ends and locking the pins in place.
The last two pictures are taken here at home where the lighting isnt the best but the red contrasts nicely with the white.
DSC09564 (Medium).JPGDSC09567 (Medium).JPGDSC09568 (Medium).JPG
 

ALPER SARISAN

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May 13, 2019
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362/5000



Hello to everyone .
I started cri cri construction 3 years ago. Your manufacturing know-how has been very useful to me. you can see my construction stages on my page below
I have a question for you.
Where can I get cri cri's canopy bobble flour?
I would be very glad if you could help me with this ...
 

MadRocketScientist

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Canterbury, New Zealand, Earth, Milky Way Galaxy.
After waiting for over two months, the shipment with the ball lock pins finally arrived from china!

The quality is actually alright. The push button springs do have a slight variation in the pressure required to release them but still not bad for under NZD$10 each. I think I will cut all the cables off to keep weight down. ;)

The other thing is, I had completely overlooked that the holes that these go into will need to be reamed to fit, but do you think I can find a 6mm reamer around anywhere? I will have to order one and wait for it to arrive, so until then I can't fit these secondary pins to hold the wings in place.
 

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proppastie

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those pins from China....Slightly hollow? How hard/strong???? If the plans called out for AN hardware or equal for the wing attach bolts I am not sure I would trust Chinese hardware without testing and certainly a hollow shaft of the same diameter and hardness as solid shaft will not be as strong.
 

MadRocketScientist

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Location
Canterbury, New Zealand, Earth, Milky Way Galaxy.
those pins from China....Slightly hollow? How hard/strong???? If the plans called out for AN hardware or equal for the wing attach bolts I am not sure I would trust Chinese hardware without testing and certainly a hollow shaft of the same diameter and hardness as solid shaft will not be as strong.
The plans have two versions, you can make your own pins from 4130 tubing or use off the shelf pins. The China pins are stainless and there is a mechanism through the middle that locks and unlocks the balls. They should be plenty strong enough.
 

Jim_MC15

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Oct 30, 2018
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2
The plans have two versions, you can make your own pins from 4130 tubing or use off the shelf pins. The China pins are stainless and there is a mechanism through the middle that locks and unlocks the balls. They should be plenty strong enough.
Wait... What? You didn't make your own??? Probably easier than say, dual spark plug cylinder heads, wheels, formed wing tips, canopy latches.... LOL :)
 
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