Today's Message Index:
----------------------
1. 12:40 AM - Re: Aerodynamic clean-up ideas (douglas.lindsay)
2. 06:03 AM - Re: Re: What a joke (Mark Hubelbank)
3. 06:24 AM - Re: Re: What a joke (Paul Mulwitz)
4. 11:45 AM - Re: Re: What a joke (Afterfxllc@aol.com)
Message 1
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| Subject: | Re: Aerodynamic clean-up ideas |
Thanks everyone!
We've now bought the aircraft so going to fly it for a season and then implement
as many of these ideas as we can over the winter.
Happy flying!
Doug
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=338721#338721
Message 2
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Is it being suggested that the loctite is not really required? It
appears that the original nuts were locking and the replacements are
not. Still we use other bolts in critical places which have no locking
method like head bolts. I find the idea of using Loctite questionable as
I believe it can increase the risk of improper torque applied and if one
has to remove it, Loctite claims the temperature to weaken it is 250C,
To get anything that hot, parts are much hotter. One would think the
bolt strength would be compromised by over heating. According to SAE
J429 heat treated bolts should not be subject to temperatures over 260C.
I think this means that if a nut ever has to be removed the bolt (and
cylinder?) has to be removed.
On 05/02/2011 1:20 AM, Thruster87 wrote:
> --> Zenith601-List message posted by: "Thruster87"<alania@optusnet.com.au>
>
> A local flight training center that has been using Jabiru aircraft for the past
12yrs, swears by the new nut modification,they found that the new nuts can
be torqued more easily [the small nuts feel like they are going to strip the threads
during torquing] and since doing the SD have NOT had any more issues.Also
they have a wobble bar [10"] which they ground to move about 10 deg and they
ground the socket walls so it would fit in.This way NO need to remove any bits
from the engine.The jury is still out on the need to use loctite,as without
it it would make it a lot easier to re-torque the nuts/studs. Cheers
>
>
> Read this topic online here:
>
> http://forums.matronics.com/viewtopic.php?p=338613#338613
>
>
--
Mark Hubelbank
NorthEast Monitoring
2 Clock Tower Place
Suite 555
Maynard, MA, 01754 - USA
mhubel@nemon.com
978-443-3955
Message 3
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Hi Mark,
I don't know why I am getting into this conversation, but I guess my
experience making knives comes into play here.
When heat treating steel, the temperature is raised to a desired
temperature to reduce brittleness. For tool steels this is usually done
to at least 900 or 1000 degrees F. I'm not sure exactly what
temperature aircraft bolts are heated to, but I'm quite sure it is well
above 250 C. So long as the temperature is kept below the heat treating
(tempering) temperature I don't think the characteristics of the steel
will be impacted.
I also wonder what role LocTite or other friction devices might play
here. The large diameter nuts in question should be torqued to a very
high and consistent level. I would hope this would keep them from
coming loose under expected conditions of vibration and temperature.
Lastly, I wonder why amateur builders think they know more about how to
keep an engine running properly than the designers of that engine.
Paul
XL Jab 3300 soon to enter flight test.
On 5/3/2011 5:57 AM, Mark Hubelbank wrote:
>
> Is it being suggested that the loctite is not really required? It
> appears that the original nuts were locking and the replacements are
> not. Still we use other bolts in critical places which have no locking
> method like head bolts. I find the idea of using Loctite questionable
> as I believe it can increase the risk of improper torque applied and
> if one has to remove it, Loctite claims the temperature to weaken it
> is 250C, To get anything that hot, parts are much hotter. One would
> think the bolt strength would be compromised by over heating.
> According to SAE J429 heat treated bolts should not be subject to
> temperatures over 260C. I think this means that if a nut ever has to
> be removed the bolt (and cylinder?) has to be removed.
>
> On 05/02/2011 1:20 AM, Thruster87 wrote:
>> --> Zenith601-List message posted by:
>> "Thruster87"<alania@optusnet.com.au>
>>
>> A local flight training center that has been using Jabiru aircraft
>> for the past 12yrs, swears by the new nut modification,they found
>> that the new nuts can be torqued more easily [the small nuts feel
>> like they are going to strip the threads during torquing] and since
>> doing the SD have NOT had any more issues.Also they have a wobble bar
>> [10"] which they ground to move about 10 deg and they ground the
>> socket walls so it would fit in.This way NO need to remove any bits
>> from the engine.The jury is still out on the need to use loctite,as
>> without it it would make it a lot easier to re-torque the nuts/studs.
>> Cheers
>>
>>
>>
>>
>> Read this topic online here:
>>
>> http://forums.matronics.com/viewtopic.php?p=338613#338613
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>
Message 4
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Well Paul
If you read 4130 it has standards that I and everyone else needs to follow.
I have shown this fix to a few A&P's that have said they would NOT sign off
if this was on an engine this way. Jabairu has a history of an engine that
overheats and distorts cylinders and this is just another example of piss
poor engineering.
Ask yourself if you would see this on a lycoming or Continental and the
answer is no and the reason is because they have to build them to standards
where others use experimental as a way to get away with anything.
Jeff
> Lastly, I wonder why amateur builders think they know more about how to
> keep an engine running properly than the designers of that engine.
>
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