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Discussion Starter · #1 ·
In the Solitron Jr. thread I was reading that Jr. is good for powering 200hp continuously. What DC motors (if any) out there can produce 200hp continuously? Also, would arcing be a problem for DC motors at high altitude where the air is thinner?
 

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don't know about the DC motors, but I do remember my magneto's arced like crazy above 15000 (not that I was supposed to be up there). Most of the EV planes I've seen via the EAA don't go that high or use odd motors.
 

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Discussion Starter · #3 ·
don't know about the DC motors, but I do remember my magneto's arced like crazy above 15000 (not that I was supposed to be up there). Most of the EV planes I've seen via the EAA don't go that high or use odd motors.
Yeah, I think they focus on AC motors so they can run "brushless."

Your magnetos shouldn't be arcing at only 15,000' - in WWII fighter planes using the same technology flew to over 30,000' without difficulty and I routinely fly that high with no trouble (only one mag, replaced the right with electronic ignition). But, I'd be curious to know how you knew they were arcing, or why you would say that you shouldn't be up there (that's usually still VFR airspace)? Is it an ultrlight? Well maybe best you not say since this is a public forum... :D
 

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Yeah, I think they focus on AC motors so they can run "brushless."

Your magnetos shouldn't be arcing at only 15,000' - in WWII fighter planes using the same technology flew to over 30,000' without difficulty and I routinely fly that high with no trouble (only one mag, replaced the right with electronic ignition). But, I'd be curious to know how you knew they were arcing, or why you would say that you shouldn't be up there (that's usually still VFR airspace)? Is it an ultrlight? Well maybe best you not say since this is a public forum... :D
High altitude aircraft engines deal with arcing one of two ways - usually they use pressurized magnetos or might also design larger mag's which have increased distances between the (distributor block's) electrodes for the various cylinders combined with small plug gaps (to make it easier for the spark to occur where it's supposed to, i.e. in the combustion chamber).
 

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Discussion Starter · #6 ·
High altitude aircraft engines deal with arcing one of two ways - usually they use pressurized magnetos or might also design larger mag's which have increased distances between the (distributor block's) electrodes for the various cylinders combined with small plug gaps (to make it easier for the spark to occur where it's supposed to, i.e. in the combustion chamber).
That may be true - but in general anything below 25,000' isn't considered "high altitude." I routinely fly up to 17,500' without any evidence that my mag is arcing.
 

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That may be true - but in general anything below 25,000' isn't considered "high altitude." I routinely fly up to 17,500' without any evidence that my mag is arcing.
Not sure if magnetos are OT, but there are many variables that go into whether arcing will occur. Yes, altitudes <18,000' may not be considered to be high alt., but neither are they necessarily low altitude. I think many if not most aircraft engines designed for use above 12,000' (i.e. turbocharged) have pressurized mags. I'm not sure but that might be the difference. Non-turbo engines would have low cylinder (manifold) pressure and may not experience arcing for that reason - whereas a turbo'd engine could if the mag wasn't pressurized also. Since you have one mag and one electronic ignition, I might assume you're flying an amateur(home)-built craft in which case it would depend on the components you selected for your engine.

More On-topic: I'm considering installing electric drive to my homebuilt rather than the ICE in the original plans. However, I'm not planing to use it over 10,000' so I don't think I'll need to worry about arcing. Are others here thinking about installing electric drives in their aircraft?
 

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well: no o2, service ceiling was 12000 (1930 technology), and the engine misfired something fierce, found burned stuff inside the mag when I got down and tore it apart. BTW way above 15000 in a thermal.

i'm thinking something with advanced brushes or interpoles probably should be OK, but not a 36v forklift motor running on 300v.

I also only used max throttle at takeoff, usually only 65% during normal flight so perhaps 50 hp would be enough if over amped for takeoff?
 

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There is just something not right about an electric airplane. I wouldn't step 1 foot in one. :)
 

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There is just something not right about an electric airplane. I wouldn't step 1 foot in one. :)
Why is that?:confused:

As an Ev'er, you know about the MUCH greater reliability of an electric motor over ICE. The lower noise and vibration are less fatiguing on both the people and the airframe. Then there's the lower cost of operation (fuel, oil & maintenance).

And a farfetched reason - electric aircarft can't be used as a flying bomb :eek:, therefore would be better for national security.
 

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Discussion Starter · #11 ·
Not sure if magnetos are OT, but there are many variables that go into whether arcing will occur. Yes, altitudes <18,000' may not be considered to be high alt., but neither are they necessarily low altitude. I think many if not most aircraft engines designed for use above 12,000' (i.e. turbocharged) have pressurized mags. I'm not sure but that might be the difference. Non-turbo engines would have low cylinder (manifold) pressure and may not experience arcing for that reason - whereas a turbo'd engine could if the mag wasn't pressurized also. Since you have one mag and one electronic ignition, I might assume you're flying an amateur(home)-built craft in which case it would depend on the components you selected for your engine.
That sounds right, I've heard of pressurized mags but also know many aircraft without turbos flew in WWII. I have one of these (sample photo, not mine), and one day would love to strip the ICE and go electric. So, in seeing Solitron Jr. advertised as 200hp continuous I started thinking... :D That, BTW, would be 40hp more than I currently have at Sea Level on a "standard day" (which almost never happens in Atlanta). I suspect I'd see over 2,000'/min climb with 200hp constant power...

More On-topic: I'm considering installing electric drive to my homebuilt rather than the ICE in the original plans. However, I'm not planing to use it over 10,000' so I don't think I'll need to worry about arcing. Are others here thinking about installing electric drives in their aircraft?
See above - yes very much so but not until the range issues are solved. I would settle for a bit more weight (not much) to retain my 1,000 mile range. Electric would have another advantage in that I could completely close out the cowling (or, simply have very small "blast tubes" for cooling). That means that I would have less drag at the same airspeed, which would make up some for the extra battery weight.

But, it will have to wait until some of the infrastructure starts getting built out to accommodate electric. "Around the lake" planes are no problem, but for a cross-country plane you need to know you can charge up at your destination...
 

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Discussion Starter · #12 ·
Why is that?:confused:

As an Ev'er, you know about the MUCH greater reliability of an electric motor over ICE. The lower noise and vibration are less fatiguing on both the people and the airframe. Then there's the lower cost of operation (fuel, oil & maintenance).

And a farfetched reason - electric aircarft can't be used as a flying bomb :eek:, therefore would be better for national security.
Anything can be used as a weapon.

But, you are more right about reliability than you know. Many failures BESIDES the engine are caused by ICE engine vibration - gets expensive when a $10,000 radio takes a nap because of too much shaking... :eek:

Electric will be a HUGE improvement. Since electric creates full hp over a wide range of RPM, it virtually eliminates the need for a variable pitch propeller. Simply pitch the prop so that during climb you only turn 1/2 of max rpm - you will still be making nearly full hp. At cruise, just let the rpms climb. As they increase, the prop provides more resistance until it balances drag against torque.
 

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OK, now to the hard questions: How much KWH can you put in there, and about how much energy do you need for 1000 mi with reserves?? a BTU derived from gallons burned conversion is in order. batteries in the wings?

Never saw an airfield that couldn't run 110 out to the plane, 220 meant you have to find a mechanic/hangar.

I'm guessing a Lanc 235 or the next one up in the line? opening up the wings will be a real joy.
 

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Why is that?:confused:

As an Ev'er, you know about the MUCH greater reliability of an electric motor over ICE. The lower noise and vibration are less fatiguing on both the people and the airframe.
Not speaking so much as reliability, but useful fuel load, range, and reserves to be practical. Battery energy densities just are no where close to being practical for electric aircraft in my opinion.

EV motors at cruise speed are a lot like their ICE counterparts in that they only require 10 to 20% of their full power rating. However aircraft engines and motors need to run at 70 to 90% full power at cruise and thus use substantially more power for a given weight.
 

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That sounds right, I've heard of pressurized mags but also know many aircraft without turbos flew in WWII. ... I suspect I'd see over 2,000'/min climb with 200hp constant power...

... Electric would have another advantage in that I could completely close out the cowling (or, simply have very small "blast tubes" for cooling). That means that I would have less drag at the same airspeed, which would make up some for the extra battery weight.

But, it will have to wait until some of the infrastructure starts getting built out to accommodate electric. "Around the lake" planes are no problem, but for a cross-country plane you need to know you can charge up at your destination...
RE: WWII engines - most combat aircraft were supercharged in some form (turbo or gear driven) to perform at altitude or just make more hp for given size engine. However, reliability was low - Mustang's Merlin had 500hr TBO.
An electric aircraft (EA) motor would benefit you in two ways - first, you've already noted is significantly reduced cooling drag and its associated other heat problems. Second, hp is maintained with altitude - effectively acting like a "turbocharged" aircraft.

RE: infrastructure - springing for the cost of hangaring for the night would gain you access to power for charging, quite possibly 220V as most shops have large air compressors or welders that require it. Many FBOs have let me plug in my RV when at their field. (but then I was buying 100's of gallons of avgas for my WWII aircraft, an SNJ/AT6.)
 

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OK, now to the hard questions: How much KWH can you put in there, and about how much energy do you need for 1000 mi with reserves?? a BTU derived from gallons burned conversion is in order. batteries in the wings?

Never saw an airfield that couldn't run 110 out to the plane, 220 meant you have to find a mechanic/hangar.

I'm guessing a Lanc 235 or the next one up in the line? opening up the wings will be a real joy.
You're right, Piotrsko, stored KWH is an issue just yet but won't be for long. However, I expect significant improvement soon. I just a few years I've effectively doubled or even quadrupled my expected range for my MG. More than 20miles was unrealistic using Pb in it. Now, with LiPO4, I can easily expect 60mi. or more if I'm willing to give back the trunk space I gained by changing battery type. Better chemistries are on the way now that it's of commercial interest to auto and renewable energy companies. I can't say for sure but Moore's Law may apply to energy storage as well as transistors for processing power.

Putting storage lockers in the wing is definitely possible provided structural integrity is maintained. And for efficient craft like Phantom's Lancair, and hour to two endurance can get you 200-500 miles "down the road". While not exactly transcontinental, I would call that cross country range. Besides, these days my bladder doesn't last any longer than a few hours.:D
 

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You're right, Piotrsko, stored KWH is an issue just yet but won't be for long. However, I expect significant improvement soon. I just a few years I've effectively doubled or even quadrupled my expected range for my MG.
That is still not enough IMO. Right now LFP is what? At best case 0.72 MJ/Kg compared to gasoline/diesel of 46 MJ/Kg. I hope to live long enough to see it, but I am not holding my breath nor would I wager my grand children would see it.
 

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what is it going to take to cruse at the low cruse 50% power level . Most of the aircraft engines don't make advertised power(engines tested without exhaust systems ) , who knows what the real power is at 1/2 power . how much thrust is developed ? thrust moves the airplane not hp . Hopefully ev power will need to be somewhat less then gas numbers would indicate .
 

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That is still not enough IMO. Right now LFP is what? At best case 0.72 MJ/Kg compared to gasoline/diesel of 46 MJ/Kg. I hope to live long enough to see it, but I am not holding my breath nor would I wager my grand children would see it.
That's the energy content of the fuel. In terms of fuel doing actual work it's more like 10MJ/Kg (3 KWH/Kg) for a perfectly tuned test stand engine. That's 30X large prismatic LiPO4 cells (~100 WH/Kg). If Moore's Law were to hold for electric energy storage, we will have effective parity between liquid fuels and electric storage in 10 years. I think that's within OUR lifetime and certainly with our children's.

OTOH, the motor would be ~100Kg less the ICE. Typical small aircraft has 200 Kg Ice plus 150 Kg (~50gal) fuel load; that's ~82KWH assuming 100Kg for motor/controller, etc. for current off the shelf components. Ignoring performance improvements available from electric power as discussed previously.

Further, electric power has the advantage of high torque at low RPM; the most efficient thrust comes from slow turning, large diameter props/fans. That's why modern jet engines (747, 777) have the size/shape they do vs. small diameter pods of the 1960's (727, DC9).

So Phantom, better start thinking about conversion for your Lancair. The EPA & FAA want to get rid of 100LL fuel soon anyway. :D

Edit: I'm planning on skipping the ICE for my current airplane build project (Avid Amphibian) and going straight to electric - but first I need to get the MG done for my wife. She want to show it off to her friends.
 
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