REFLECTOR: It's been really quiet this week

Tue Feb 18 09:43:10 CST 2014

Hmm, I am a proponent of reducing timing to lower CHT's, and have my mag 
and EI set to 28BTDC, advancing to 32BTDC above 2600 RPM.  The book 
value is 28-32 degrees.

I will retard it some more and we'll see what happens.

On the EI, I am running NGK Iridium IX plugs, with a fairly shallow 
reach.  I don't have the exact rating available at the moment.

I am seeing conflicting data.  My gasket thermocouples are reading 
redline temps on takeoff, but the bayonet thermocouples are reading 
cool.  Do you know what could be causing this?

On 2/18/2014 8:51 AM, John Dibble wrote:
> On 2/17/2014 11:44 AM, Brian Michalk wrote:
>> I've been flight testing.  It's a slow process for me, since my 
>> engine design while Franklin based, has EFI and EI.
>> I have been battling high CHT's even in the cooler weather, and am 
>> seeing positive results as the engine breaks in.
> Sorry for repeating myself, but I really think you need to reduce the 
> timing advance to 24-25 degrees.  My anecdotal experience has been 
> that any departure from the mag/massive electrode combination 
> increases the detonation tendency for the Franklin engine. Further, 
> multiple changes compound the problem.  When I bought my plane it had 
> one mag and one EI, both using massive electrode plugs.  I experienced 
> minor detonation symptoms such as an occasional plug fouled with metal 
> and an occasional high CHT. When I switched to auto plugs for the EI, 
> the symptoms worsened with more frequent plug fouling, erosion of the 
> electrode and an occasional engine stumble right after takeoff, a real 
> attention getter.  When I switched the mag plugs to fine wire, the 
> engine stumbling became more frequent and I had to replace a cylinder 
> and piston due to severe pitting.  I have eliminated the symptoms by 
> reducing the timing advance.  I manually increase the EI advance once 
> I'm above 9k for max power.  Maybe Mike W will comment also.
>
> John
>
>>
>> Specifically, I've been testing the forward CG limits, and have 
>> decided that my decision to move equipment as far forward as possible 
>> was a bad one.  I was intending to have Juanita be able to fly the 
>> airplane without ballast, but with my weight, I can't really carry 
>> much in the copilot seat.  I mounted a big Optima Red Top at a 15 
>> inch arm location.  This weekend I relocated it temporarily to just 
>> forward of the whales tail, but for a permanent solution, I am 
>> looking at some of the really lightweight batteries that are out 
>> there, and am having a hard time making up my mind.
>>
>> Option 1: some lightweight lead/acid battery
>> Option 2: an alternative chemistry
>>
>> For option 1, John mentioned the Braille batteries.  I looked online, 
>> and people seem to think that Braille is stretching their performance 
>> numbers, but if Velocity is using them, then that's a pretty good 
>> endorsement.  There are also Odyssey batteries that look pretty good 
>> as well.
>>
>> Option 2 for me would be the new LiFe (Lithium Iron) batteries that 
>> are used in some motorcycles, snowmobiles and jet skis. Those are all 
>> pretty high vibration environments, which was my first concern.  
>> Next, they are really incredibly lightweight.
>> Now, when these batteries reach 13 volts, they are basically dead, 
>> with 30% capacity remaining.  They are fully charged at 14.3 volts, 
>> and appear to take a charging voltage up to 15 volts.  For me, I'd 
>> need to convert my internal regulated alternator to external, and 
>> bump up the voltage to accommodate these new batteries.
>> Another down side is, like the LiPo batteries, these need to have the 
>> cells balanced.  There is a special connector that ensures all of the 
>> cells are charged to their proper voltage, but balancing a battery 
>> doesn't have to be performed for every charge.  I also think that 
>> rather than charging through the balancing port, a person could use a 
>> hobby grade balancer that places a load on cells to draw down their 
>> voltage, achieving the same goal.  Bulk charge through the terminals, 
>> then balance by discharging excess capacity.
>> And another downside is that they like to be stored at something like 
>> 80% capacity.  This may be fine for our needs. As long as they can 
>> start the plane, they can be charged at high currents, so within a 
>> few minutes after starting they would be at 100%.
>> Okay.  For one final upside:  The higher operating voltage will spin 
>> a prop faster, and will have smaller voltage drop in your cables.  
>> I'm solid state switching, losing a couple of tenths of volts across 
>> each solid state relay.  This bump up in voltage would really be nice 
>> for my electric gyros, which are always complaining about low voltage 
>> until I bring up the engine RPM's.
>>
>>
>>     LFX19A4-BS12MSRP: $199.95
>>
>> SHORAI LFX Lithium-ion Powersports battery,19AH 12V, "A" polarity, 
>> Case Type 4
>> Length 5.83"
>> Width 3.39"
>> Height 3.46"
>> Weight 2.32lbs
>> CCA 285amps
>>
>> I would need two of those, which would put me at the lower end of my 
>> CCA requirements.
>> www.shoraipower.com
>>
>
>
>
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