Originally Posted by chaps

Hi Mike

Mann that plane is a beast, do you think you'll have it at monarto and what mode
Once again that is an awsome plane and i hope we get to see it at Monarto and i hope you get the prop spitting sorted out.

Matty

Hey matty , , I can put it onto matty mode but your old man will need to bring that cheque book of his

Just waiting for Bill to get back to me about prop and spats and as TD has suggested will need to have a good look at motor and check the crank etc. No chance for Monarto.
Maybe next year.
Mike

Originally Posted by 3dubya

hi mike, wise words from howie when a prop came of a DA150 at the masters one year, he said "only 2 reasons a prop comes off, bolts were done up too tight or they were too loose". Unfortunately when all these boxer motors fling a prop its highly likely the crank gets knocked out of alignment (remember mine came off at monarto last year, it got knocked out a mile, most of the repair work that was done on mine by uncle ernie that night was realigning the crank). Continuing to fly it with miss-aligned crank is a very very bad idea even if its slight. The motor will potentially fling a prop again with all the vibration, and all sorts of things will come loose like the heads and gaskets will suck in or blow out.

Take it to a good gocart shop and get the crank dialed up, it may not be out at all but its not worth the potential nightmare. DA-3W-DL all are POS if the crank is out.

Thanks TD, all sounds like good advice. I will have to draw the conclusion they were to tight as I know they were not loose. The Beila carbon I used had a wooden hub and a few guys have looked at it and said the centre may have collapsed as all the carbon has broken of like a washer on the back of the prop.

its definitely hard to get the tension right on a wood hub cause the dam things crush, big forces would be on that size donk. id be drilling out the bolt holes in prop inserting metal collars down the bigger holes so the bolts do up on the collars to stop crushing. Maybe there would be problems doing this but its an idea

That is a good idea. There is no stress marks on the top or sides of the prop only on the bottom.
The other freeky thing is the motor kept running after it spat the prop. I havn't seen that before.

I use a torque wrench for all my prop bolts including wood. with the wood I generally torque it in 5-10lbs increments until I get to the desired torque. this essentially "crushes" the prop evenly.

Originally Posted by Aussieaero's

Hey matty , , I can put it onto matty mode but your old man will need to bring that cheque book of his

Just waiting for Bill to get back to me about prop and spats and as TD has suggested will need to have a good look at motor and check the crank etc. No chance for Monarto.
Maybe next year.
Mike

Got your email.... no problem on the spats and the prop. The Tru-turn (3) blade will take time as these are a custom cut. I do have a C/F (3) blade that is much cheaper if interested.
Anyway, look for my email, I will get an invoice to you.

BIll

Originally Posted by toc pilot

Got your email.... no problem on the spats and the prop. The Tru-turn (3) blade will take time as these are a custom cut. I do have a C/F (3) blade that is much cheaper if interested.
Anyway, look for my email, I will get an invoice to you.

BIll

Hi Bill, think I would prefer to use the Tru turn again.
Thanks for your help
Mike

Another thing I would look at is the length of your prop bolts. Wind them into the prop hub without the prop fitted until they bottom out, then measure the exposed length of the bolt, then measure the thickness of the prop hub, make sure the prop hub is at least 4mm thicker than the exposed length of the bolt, this will ensure you get positive clamp up, and not a false impression of the bolt being tight as it bottoms out. We have seen this before.

Originally Posted by kevinf2501

I use a torque wrench for all my prop bolts including wood. with the wood I generally torque it in 5-10lbs increments until I get to the desired torque. this essentially "crushes" the prop evenly.

Thanks for the advice I will have to do this in the future I think.

Originally Posted by rcdart

Another thing I would look at is the length of your prop bolts. Wind them into the prop hub without the prop fitted until they bottom out, then measure the exposed length of the bolt, then measure the thickness of the prop hub, make sure the prop hub is at least 4mm thicker than the exposed length of the bolt, this will ensure you get positive clamp up, and not a false impression of the bolt being tight as it bottoms out. We have seen this before.

Hi Mick, Your suggestions just found me back in the shed double checking as I had to replace the original prop bolts with longers ones to suit the biela prop. As it appears the prop has come loose before it departed there was a good possibility in what you suggested, however, I just rebolted what was left of the prop back into the motor using the same size bolts and am able to bolt the prop up tight with out the spinner backing plate. The spinner backing plate thickness is about 5mm in the centre and of course this was on for the maiden. So the mystery continues, thanks for your help.
Mike

Originally Posted by Aussieaero's

That is a good idea. There is no stress marks on the top or sides of the prop only on the bottem.
The other freeky thing is the motor kept running after it spat the prop. I havn't seen that before.

its a shame Mezjlic don't make a prop for that size motor, there must be a market for them by now

maybe contact them and see what their plans are http://mejzlikmodellbau.inshop.cz/in...es/contact.htm

Originally Posted by 3dubya

its a shame Mezjlic don't make a prop for that size motor, there must be a market for them by now

maybe contact them and see what their plans are http://mejzlikmodellbau.inshop.cz/in...es/contact.htm

just sent them an email

Originally Posted by Aussieaero's

Hey matty , , I can put it onto matty mode but your old man will need to bring that cheque book of his

Just waiting for Bill to get back to me about prop and spats and as TD has suggested will need to have a good look at motor and check the crank etc. No chance for Monarto.
Maybe next year.
Mike

oh thats no good. , i hope the fix is easy and doesnt lighten the ewallet too much. The Wild Hare flys really good as well so i guess that will be your weapon of choice. I still havnt got the SuperXtra going so i will be flying the 2.6 still. I hope to have it going by the asaa at dubbo though.

matthew

Originally Posted by 3dubya

its a shame Mezjlic don't make a prop for that size motor, there must be a market for them by now

maybe contact them and see what their plans are http://mejzlikmodellbau.inshop.cz/in...es/contact.htm

TD heres there response.

Hello Mike,

The largest prop we are making is 34x12 2-bladed or 31x12 3-bladed. We do not plan to make bigger props for now.

Best regards,

Aleš Randáček
export sales manager

ales.randacek@mejzlikmodellbau.com

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MEJZLIK MODELLBAU

Ph: +420 54321 8888

Fax: +420 54321 8880

Cell: +420 776 337763

www.mejzlikmodellbau.com

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Here is the video of the maiden, sorry about the wind noise. You can see the prop and spinner come off at about 3.11 .

50% edge maiden Flight (4 min 38 sec)