Eagler's Nest
Airframes => Single Seaters => Topic started by: Steve on July 13, 2016, 01:57:23 PM
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PRO's-----------
-The Minimax weighs 1.1 pounds - Milholland prototype battery weighs 7.2 pounds
-Using the Minimax you can eliminate the Voltmeter and ignition switch, approx 1 pound installed
-Can be recharged in car or at home
-Does not need to be hard mounted and therefore not part of the empty weight
-7.1 pounds that you do not need to carry on every flight...
-Dead simple primary ignition circuit - a grounded receptical and a hot wire to the Blue Coil
-Les Holman says his 009 distr engine runs better and starts easier than the mag fired engine (he flys both)
CON's
Reliability in our service application is unknown
No one has done the testing in an engine stand
This is a real opportunity for a new engine builder to do some R&D
Link to Minimax battery: https://www.amazon.com/MiniMax-29916-Portable-Charger-Minimax/dp/B01CJH1ZBO/ref=sr_1_1?ie=UTF8&qid=1468441070&sr=8-1&keywords=minimax+battery (https://www.amazon.com/MiniMax-29916-Portable-Charger-Minimax/dp/B01CJH1ZBO/ref=sr_1_1?ie=UTF8&qid=1468441070&sr=8-1&keywords=minimax+battery)
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Specs on that battery say "7,800mAh" which is 7.8 Ah. What is the current draw for the 009 Distributor ignition?
A 7 lb Yuasa (first specs I could find) battery runs about 11 Ah so you are giving up 30% of the battery capacity. Might work. For awhile.
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What is the current draw for the 009 Distributor ignition?
Great Plains lists a 4 cylinder, dual plug, dual coil 009 with wasted spark setup as 4 to 5 amps.
I take that to mean a single coil 2 plug setup up with 2 cam lobes ground off should be 1 amp or so...
http://greatplainsas.com/screardr.html (http://greatplainsas.com/screardr.html)
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What is the current draw for the 009 Distributor ignition?
Great Plains lists a 4 cylinder, dual plug, dual coil 009 with wasted spark setup as 4 to 5 amps.
I take that to mean a single coil 2 plug setup up with 2 cam lobes ground off should be 1 amp or so...
http://greatplainsas.com/screardr.html (http://greatplainsas.com/screardr.html)
I found a cross reference on the 009 on 4 cyls drawing about 4 amps...
However, when the distributor 1 & 3 cyl lobes are ground off the primary coil circuit is hot a much longer time per revolution... To reduce the load time the distributor lobe valleys between 1 & 3 would need to filled with weld and ground true with the lobe tops to get it down to less current per revolution...
My guess is the Minimax battery is good for about an hour... I saw a rating somewhere for it to be between 2 & 4 ah's...
A direct Lithium replacement for Leonard's lead acid sealed battery is found here: http://www.powerstream.com/LLLF-12v-7ah.htm (http://www.powerstream.com/LLLF-12v-7ah.htm)
It weighs 4.9 pounds less!...
It still needs ground testing to figure out when to charge up because the voltage has an abrupt drop off in Lithium batteries!...
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My yellow eagle with 009 uses about 2 amps. Intse a 7 ah batter and get 2 hours easy. I believ i can get closer to 4 before it would affect engine operation. With 2 @ 7ah i have been to 6.5 hours
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If one wants to get "experimental" with electrical power source...
Something like this is becoming feasible: 40W semi-flexible solar panel (http://www.eco-worthy.com/catalog/worthy-semi-flexible-monocrystalline-solar-panel-p-218.html)
Spec'd at 3.3 lbs and 2.3A output. Add another 0.24 lbs for the solar controller.
Would still need a small battery but the size could be reduced without impacting duration.
I would also think with a total loss electrical system instrumentation something like this: Bayite digital display voltage/current/power (https://www.amazon.com/bayite-6-5-100V-Display-Multimeter-Voltmeter/dp/B013PKYILS)
I just put one of these in my RV and they are small and light and track current in real time and calculate power consumed so you would know how much battery you used/had left. This meter is a bit limited in a solar system as it only tracks current out, not in, so you lose some important information whenever solar output exceeds the load (and thus battery charging occurs).
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I found a cross reference on the 009 on 4 cyls drawing about 4 amps...
However, when the distributor 1 & 3 cyl lobes are ground off the primary coil circuit is hot a much longer time per revolution... To reduce the load time the distributor lobe valleys between 1 & 3 would need to filled with weld and ground true with the lobe tops to get it down to less current per revolution...
I did a little more digging...
The blue coil has a primary resistance of 3 ohms. Current equals Volts divided by Resistance, commonly written as E = IR.
So yes the current would be 4 amps. This with the "key on and the points closed"...
However with the engine running it comes down to how long the points stay closed (dwell angle), inductance, capacitance, ETC.
So it comes in less than the 4 amps, and it comes in less the higher the rpm, because the dwell is less like Steve said.
And like Steve said about the lobes on the distributor cam, you would need to put roundness between the lobes instead of flatness to keep the points open.
The Pertronix hall effect trigger (http://pertronix.com/prod/ig/ignitor/) would accomplish this if you simply removed 2 of the magnets, but who knows if it actually would save battery current, overall.
All this being said, I am still perplexed at how Great Plains came up with 4 amps with 2 coils. Probably has something to do with the wasted sparks...
The Tesla has nearly 7,000 Lithium Ion 18650 cells. (http://www.teslarati.com/tesla-move-away-battery-technology/)
These are readily available and would be a worthy experiment because you can control the capacity by adding more cells.
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I, running a Geni Pod to recharge my system = even with starter motor, radio, Blue coil and 009 im finding with a 30 /45 min flight
im coming back in with what i took off with, i am a bit quicker (DE) than a LE for spinning the Geni Pod
The last 3 hrs have 5 engine starts with couple ground runs (carby Set Up) and just under 2.7 hrs flying and have not had to apply
a battery charger yet = Total worth the purchase of the Geni Pod