Author Topic: Mike Palko's P51 (Read 3783 times)

Bill Mohrbacher · « **on:** June 13, 2008, 07:37:09 AM »

I was down at Brodak's yesterday and saw Mike's new P51. Beautiful plane and very nice flight.

Dennis Toth · « **Reply #1 on:** June 14, 2008, 03:56:33 PM »

Great looking ship!!!!!! Whats the setup?

Best, Dennis

Bill Mohrbacher · « **Reply #2 on:** June 15, 2008, 05:07:56 PM »

Mike will have to give you the details

Mike Palko · « **Reply #3 on:** June 15, 2008, 07:03:07 PM »

Hi Guys,
First off I have to thank Bob Hunt for inviting Dan Banjock and myself into his shop about 8 years ago to build the Mustang(s) you see here. Dan finished and flew his "Miss Suzy Q" from ~2002-2006. Little did any of us know it would take me 8 years to finish mine and that the piped PA .61 would be replaced by a motor and batteries...... You Reno fans will recognize her as "Bardahl Miss".

Motor: NEU 1907/2Y (inrunner)

ESC: Schulze 18.46K F2B

Battery: Thunder Power Prolite 5S2P 4000mah

Timer: Z-Tron V.4 (with needle valve)

BEC: Z-Tron (prototype)

Prop: Brian Eather 13x6 Yatsenko (sp?) copy.

AUW: 68.75oz

I only have 16 patterns on it so far, but she flew good enough off the board to bring it to the flyin. There are several trim issues I need to sort out, but it shows the most promise of any airplane I have built. I look forward to sharing more as I make progress.

Mike

Crist Rigotti · « **Reply #4 on:** June 15, 2008, 09:07:24 PM »

Mike,
Very nice airplane. do you have a copy of the instructions for the ESC? i'm interested in just the F2B instructions. I'd appreciate it. I have a 18.46K and I'm thinking of getting it converted but I'd like to know what are all changes.

Alan Hahn · « **Reply #5 on:** June 16, 2008, 07:43:26 AM »

Mike,
Nice looking plane.

Out of curiosity, what do your level flight power levels look like. I am trying to correlate some stuff in my head. Also how much capacity is left in your pack after a flight?

Dean Pappas · « **Reply #6 on:** June 16, 2008, 09:37:11 AM »

Hi Mike,
Yes, I am eager to hear how much capacity you use per flight, as well.

Dean

Dennis Toth · « **Reply #7 on:** June 16, 2008, 09:47:47 AM »

Mike,

In addition to the draw down information what do you have the flight time set at? Also why the in-runner?

Best, Dennis

Dean Pappas · « **Reply #8 on:** June 16, 2008, 11:45:22 AM »

I can answer the inrunner question!

1) To begin with, everything Steve Neu makes is top quality, and domestic made.
2) Based on the resistance and magnetization current numbers, the Neu 1900 series will be more efficient than any outrunners (though just you wait for if and when Steve produces an outrunner). More efficiency means you can carry less battery weight.
2A) I might have chosen the next up step in Kv and stayed with 4S, for a 55 to 65 ounce ship.
3) The inrunner construction of bearings at the ends of the case will do wonders for solving the chronic outrunner bearing loosening/wear problems. These are often caused by "give" in the bearing mounts in the center pylon of the outrunner. Anyone who has heard the screech of loose/bad outrunner bearings raise your hand!
3A) Only Hacker (in the A40 and above motors) and Plettenberg have a handle on that problem with their large circumferential bearings at the end of the magnet "bell". Unfortunately that costs weight.

later,
Dean Pappas

Mike Palko · « **Reply #9 on:** June 16, 2008, 04:25:23 PM »

Crist,
Kim Doherty would know better than I, but the F2B ESC has the governor with break enabled and the RPM range is limited from ~7,000 to 12,000 RPM. This is done in an effort to get a finer RPM adjustment for fine tuning lap times/power levels. There may be other changes I am not aware of.

Alan,
So far I have not data logged a flight. I can tell you the capacity put back into the pack varies from ~2550-2750, depending on the needle setting. This is with the 13x6 prop so things may change as I close in on the "right" prop.

Dennis,
The motor run time is 6min. From switch ON to wheels stop is usually ~6:30. Dean hit on many of the reasons for inrunners. The 19XX series is also available through special order with a 6mm shaft (very ridged). The motor case is machined to accept larger bearings to support this shaft. An optional fan is offered which I did not go with. Motor temps were well within check at Brodaks in the 95 deg. heat. The 19XX series is nick named "ORK" or "Out Runner Killer". It was designed to outperform the outrunner with inrunner efficiency.

My Plettenberg Orbit was very good to me for four years and Kim and Paul have also shown their reliability. I saw the potential advantage of the NEU motor, so I had to find out. So far I am very happy with it, but it is to early to say if there is a real advantage.

Dean,
Expect outrunners from Steve in the near future. It will be tough to beat the Orbit motors, but I think it will give us another very solid motor choice.

Mike

Crist Rigotti · « **Reply #10 on:** June 16, 2008, 04:37:15 PM »

Thanks Mike. Very interesting set up. See you at the NATS.

Dean Pappas · « **Reply #11 on:** June 17, 2008, 07:39:31 AM »

Quote from: Mike Palko on June 16, 2008, 04:25:23 PM

Crist,
Kim Doherty would know better than I, but the F2B ESC has the governor with break enabled and the RPM range is limited from ~7,000 to 12,000 RPM. This is done in an effort to get a finer RPM adjustment for fine tuning lap times/power levels. There may be other changes I am not aware of.

Alan,
So far I have not data logged a flight. I can tell you the capacity put back into the pack varies from ~2550-2750, depending on the needle setting. This is with the 13x6 prop so things may change as I close in on the "right" prop.

Dennis,
The motor run time is 6min. From switch ON to wheels stop is usually ~6:30. Dean hit on many of the reasons for inrunners. The 19XX series is also available through special order with a 6mm shaft (very ridged). The motor case is machined to accept larger bearings to support this shaft. An optional fan is offered which I did not go with. Motor temps were well within check at Brodaks in the 95 deg. heat. The 19XX series is nick named "ORK" or "Out Runner Killer". It was designed to outperform the outrunner with inrunner efficiency.

My Plettenberg Orbit was very good to me for four years and Kim and Paul have also shown their reliability. I saw the potential advantage of the NEU motor, so I had to find out. So far I am very happy with it, but it is to early to say if there is a real advantage.

Dean,
Expect outrunners from Steve in the near future. It will be tough to beat the Orbit motors, but I think it will give us another very solid motor choice.

Mike

Hi Mike,
So far my 0.7 W-H per ounce figure holds up. It predicts 2640 mAh! Yes, when Steve releases an outrunner it will be a killer. I suspect, now that he has a machine that will allow him to make magnets with some interesting geometries that we will see some interesting stuff. You know, a 4S 4200 has just enough energy to leave 20% capacity and you could take 4 oz out of the ship. I don't know that I would, seeing how the reports I heard say that the ship flies beautifully, but it is an option!

later,
Dean

Archie Adamisin · « **Reply #12 on:** June 17, 2008, 07:43:46 AM »

Mike,

Can't say again how great the Mustang performed. You really have something there. I was curious on the power panel you have with the anti spark switch and the main power interupt. Is that a purchased unit, or did you have to fabricate that yourself? It is difficult to make a clean electric installation with it being so new to PA and most everything happening now is experimental. Your installation was suburb. I look forward to seeing you at the NATS. I won't be competing, but I live 1.5 miles from the site.

Archie Adamisin
Muncie, Indiana

phil c · « **Reply #13 on:** June 17, 2008, 08:28:13 AM »

Dean, taking 4 oz. out of a 68+ oz. plane could only help it. The biggest negative with the smaller battery is you would be pushing it a lot closer to its limit. More likely to shorten the battery life. At $50 a cell or thereabouts I'd hate to see one burn one up!

Dennis Toth · « **Reply #14 on:** June 17, 2008, 11:11:49 AM »

Mike,

Great information will look into the NEU motors. With the in-runner what mount did you use?

Dean, What is the formula and inputs for the 0.7W-H per oz to get 2640mah for the 68oz ship? I know this must be on this board some place but I don't have a clue what to search under, please give the formula and an example.

Best, Dennis

Dean Pappas · « **Reply #15 on:** June 17, 2008, 01:14:12 PM »

Hi Dennis,
The 0.7 W-H/ oz. figure is experimental, based on a survey of a number of airplanes that are out on 70 of line (or very close to it).
I'll bet you were expecting something all fancy and theoretical

Yes Phil,
I would expect the excellent flight performance life to be reduced, but not horrible. For a wild guess, the first 100 flights on a particular pack would be competition-worthy, and the next 100 would be for practice-field or good-air use only. As a result, you would always keep a mix of different age packs. It depends.
As an extreme example, some pattern guys actually use a 4200 mAh battery for Finals flights at NATs and Worlds that saves them 1/2 lb out of their 10 lb A.U.W. (rather than the normal 5300 mAh) but these packs are probably only good for 25 flights at that useage. I certainly don't think of that as an option, but then again it's been a long while since I made the Finals!

later,
Dean

Dennis Toth · « **Reply #16 on:** June 17, 2008, 02:48:30 PM »

Dean,

OK so the formula is: 0.7W/oz*68oz= 47.6W: then using P=IV or I= P/V for a 5 cell pack at 3.7volts per cell or 18.5V we get 47.6W/18.5V=2.573Amps or 2573 mah, if running volts are 18 ish you get 2644mah, OK.

Is this correct? Sorry to be so anal but I'm and ME and like to see it laid out so I can apply it to my ship, which for the 3s2p A123 cells @ 3.4V or 10.2V and the new ship at 45oz is 0.7W/oz*45= 31.5W 31.5W/10.2V=3.088Amps or 3088mah, seem reasonable for the 4600mah pack.

Best, Dennis

Mike Palko · « **Reply #17 on:** June 17, 2008, 04:26:29 PM »

Archie,
It was nice to talk with you throughout the week. The Mustang is still in it's teething stages so it will only get better. I am looking forward to seeing your electric progress at the Nats, even if it is only show and tell.

The anti spark/arming switch is a mix of off the shelf and fabricated items. The arming switch is a modified Maxx Products unit. I removed the Deans connectors and eliminated the negative lead. I hard wired it in series with the positive lead. The first switch closes the circuit between the battery and ESC (arming the ESC). A 10ohm resistor increases the charge time of the capacitors preventing the normal spark. When the capacitors are charged (I usually wait 2 to 3 seconds), I plug the arming switch in and turn the first switch to the OFF position. Finally, I turn the second switch ON to start the flight sequence. When the flight is over I pull the arming plug and no power is supplied to the motor or ESC.

Dean,
I know you are a light weight high efficiency flier. I agree with the efficiency, but I have found power to win me over (so far). The Nats wind has been 20mph plus at times for the past 4 years or more. The Philly home field is also full of turbulence (really is a horrible field), so the extra power is nice to have. The added weight helps penetration in my opinion, so I felt I made the right choice (the only choice in my situation). This airframe still has ply doublers and other IC construction methods adding a small amount of weight. The yellow paint scheme surely added more weight than a color with better coverage. I bet you could get an easy 2-4oz out of the airframe right there. A 4S power system will give you another 4oz off easy. An AUW should be in the 60oz range without much effort. The only way to know which is better would be to try it. Banjocks Mustang tipped the scales at 62.5oz when new. 6oz of 5% & 22% Power Master weighs 5 7/8oz putting his takeoff weight very close to mine.

Just for comparison, if you got a chance to read the "Thunder Gazer" thread on SSW you would see Davids combination is ~630 sq" 65oz and a PA .75. He is looking for power/penetration in the wind and turbulence in France. Remember he still needs to add about 7oz of fuel.

Dennis,
The motor is mounted from the front using 4 3mm cap head bolts. The back of the motor rests on a ply cradle with a home brew clamp system to reduce the torque load on the front firewall.

Mike

Crist Rigotti · « **Reply #18 on:** June 17, 2008, 06:17:13 PM »

Mike,
How about some pictures of the innard's?

Dean Pappas · « **Reply #19 on:** June 17, 2008, 09:02:58 PM »

You know what, Mike?
I think I see your point! Not only that but battery life will be great at 2700 mAh.

So you are flying a 13-6. Here's the next thing you must try before the NATs. Go find a 13-6 that is available in both normal and pusher directions. It may not be the best prop, but just do the A versus B test to see what the benefits of a left-hand rotation prop are! This will of course spawn a new thread.

This is a true advantage of E-Stunt over wet. I am not exaggerating. Then of course we will have to get Bolly or Eather or APC to make the prop we want. By the way, APC make both direction 12-6 Es.

Dennis: Yes you have the math right, just remember that the units for my 0.7 figure of thumb are "watt-hours per ounce".

now that I've made enough trouble,
Dean

Mike Palko · « **Reply #20 on:** June 17, 2008, 09:18:05 PM »

Dean,
Using a pusher prop is on my to do list. I have a 13" 3 blade pusher waiting patiently in the flight box. Bob said he loved his pusher.

Crist,
I will get some pictures together and post them shortly.

Mike

Crist Rigotti · « **Reply #21 on:** June 17, 2008, 09:20:56 PM »

Thanks Mike.

Alan Hahn · « **Reply #22 on:** June 17, 2008, 09:36:43 PM »

What the heck, let me be a little controversial here.

I do understand that the inrunner is a mechanically more rigid setup than the outrunner, primarily because the outer case of the outrunner (with the magnets) is cantelevered off of the front bell. So in a high g (and gyro) maneuver like a square, the magnets can come pretty close to the laminations.

Also the inrunner is suppose to be more efficient. This is where I don't understand why that matters? Efficiency is important if the battery is kept to minimum capacity and weight. However most people seem to be stuck at the 4000mAHr sizes (4s and 5s) and are using roughly only half the capacity. So who cares about motor efficiency when there are amps to waste [and extra weight to carry]?

Yes the lightly loaded batteries last longer, but they cost a heck of a lot more too (not to mention these inrunner motors). What I am getting at is that if I have to replace my cells after a year (for example), then I get a new set the next year. If the cost is nearly half, then it is a wash (except I have new cells which might be better than the old). Now I don't know how my setup will last over time, so I'll see at the end of this year.

Dean Pappas · « **Reply #23 on:** June 18, 2008, 07:34:55 AM »

Hi Alan,
High efficiency has another benefit aside from the ability to carry less battery for the same plane. Motors with better efficiency, especially those with lower winding resistance, will apply more instantaneous current and torque for every additional percent of drive that the governor applies when the RPM is loaded down in a maneuver. This improves the governor loop and airspeed maintenance.

Of course, the stuff that Igor has been working on will provide yet another level of improvement.

later,
Dean

Dennis Toth · « **Reply #24 on:** June 18, 2008, 07:53:59 AM »

OK, being relatively new to electrics (6 mths or so) I am still learning how this goes together. To date I have stayed with the AXI out runner motors and have had reasonable success with my first ship. Now with Mike showing that the in-runners can work well also it opens up some new chooses.

One thing that is not clear is which motor type produces the higher torque for a given Volts and Current load? I thought that was the big advantage of the out runners. Also class for class (read that similar power output) which type has the weight advantage? Last, again class for class, which type can pull the most continous current (this is important if you use the A123 batteries because to get the weight reasonable you use a lower voltage, say 3s2p ~ 10V, and pull higher current say 35A)?

With the in-runner it seems that the installation would be simpler and wire routing less of a hassle since you don't have spinning parts in the motor compartment.

Best, Dennis

Mike Palko · « **Reply #25 on:** June 18, 2008, 03:48:38 PM »

Hi Dennis,
The reason this inrunner does what it does is because it was designed with using a blank sheet of paper to compete head to head with outrunners. Because of this, it is the only inrunner I know of that will give the results I am getting. NEU does offer a full line of 19XX motors, so it does open the door for other size airframes also.

I have seen graphs for the ORK motors. If I come across outrunner graphs of the same size/weight I could compare torque curves.

The mounting is not a deciding factor. It might be slightly easier/cleaner, but it depends on the room available in the fuselage. The motor is 50mm in dia. so it limits you in other ways. This to me is also not much of a limit because a wider fuselage can be built stiffer, allows for better cooling and you can use a wide range of battery configurations if you so choose.

Mike

Alan Hahn · « **Reply #26 on:** June 18, 2008, 04:39:15 PM »

Quote from: Dean Pappas on June 18, 2008, 07:34:55 AM

Hi Alan,
High efficiency has another benefit aside from the ability to carry less battery for the same plane. Motors with better efficiency, especially those with lower winding resistance, will apply more instantaneous current and torque for every additional percent of drive that the governor applies when the RPM is loaded down in a maneuver. This improves the governor loop and airspeed maintenance.

Of course, the stuff that Igor has been working on will provide yet another level of improvement.

later,
Dean

But Dean, in fact I am seeing no indication of rpm sag for my application--from my datalogger---and I am not sure anyone else is either.
How fast you can supply current only has to do with L/R, L being the inductance of the windings and R being their resistance. A lower R actually increases the rise time. Of course a lower L decreases the risetime. Maybe that is what you mean.
I really don't know how fast the governor ramps up, but the ESC is flipping the currents around about 14 times per revolution on an outrunner (every time a magnet flies by!). So on that time scale the current is able to ramp up from basically off to on (as the commutation switches). Since that is more often than a single revolution---which must relate time-scale wise to how the governor is sensing rpm changes, I have a hard time seeing that it matters!

As I said, might as well add some controversy!

Mike Palko · « **Reply #27 on:** June 18, 2008, 04:53:48 PM »

Here are some detail shots of the install. The battery tray is 3 layers of c-grain 1/32 balsa. The grain runs at different angles on each layer for stiffness (balsa ply). There is also carbon mat between each layer. The assembly was then glued together with epoxy.

The fore and aft battery stops are light ply and hard balsa. I did this to get precise CG adjustments. I used velcro in the Silencer along with a temporary balsa former as a battery locater. If I needed to move the CG I had to remove and reglue the former as needed which was tiring not to mention the velcro wears out. The battery retaining plate is 1/8" lite-ply with 2oz glass laminated on each side. The bottom side also has carbon toe for extra strength.

The ESC and timer mount very neatly. The V.4 Z-Tron is flat so it velcros to the inside of the fuselage (out of sight). This makes the timer easy to get to, but out of the way. The ESC is now mounted with a strip of velcro to make it easier to remove it need be.

The arming plug and On/Off switches almost dissapear in the black checker. The top switch is the anti-spark switch. The middle is the arming plug and the bottom switch starts the flight sequence.

Mike

Crist Rigotti · « **Reply #28 on:** June 18, 2008, 09:18:47 PM »

Very cool Mike. Thanks.

Alan Hahn · « **Reply #29 on:** June 18, 2008, 09:35:29 PM »

Mike,
That is a really nice and clean installation.

Dennis Toth · « **Reply #30 on:** June 19, 2008, 07:18:16 AM »

Mike,

Great installation pic's. One question on the other NEU 19XX in-runners, I looked at their site and tried to use their motor calculator to size for the A123 pack and a 12x5 APC E. With this battery and prop I normally run around 8700 rpm on the AXI 2820/8 for 6mins. The NEU calculator came up with their model 1902/3Y with is a 1320 rpm/V motor, I though their model 1902/2y would be a better fit for the A123 pack in that the 2Y has lower resistance and can pull higher amps then the 3Y. The NEU calculator does not allow partial throttle so the comparison comes in the predicted run time. Do the in-runners react to the part throttle settings the same as the out runners?

Best, Dennis

Mike Palko · « **Reply #31 on:** June 19, 2008, 09:37:54 PM »

Hi Dennis,
On average the inrunner will shine at higher current levels. However, I don't know that I consider the current you pulling high. There have been some purpose built outrunners used very successfully in high current levels, but it is not the norm. That being said the 19XX motors will handle anything you throw at them in PA.

I noticed NEU does not offer a 1500 Kv motor like the AXI 2820/08. If it were me I would go with the motor that will work with the pitch you want to run. If you are using a 5 pitch and want to go with slightly less pitch use the 2.5Y. If you want to use slightly more pitch use the 3Y. I think the 2Y will be a little to hot with a Kv of 2035.

Mike

Dennis Toth · « **Reply #32 on:** June 20, 2008, 07:21:53 AM »

Mike,

Thanks for the input I am leaning towards the NEU 1902/3Y because it is close to what has worked with the AXI 2820/8 and I would like to go to the APC E 12x5. That said I estimate that the rpm needed will be around 8500 rpm on 65ft @ 5.0 lap. The NEU calculator indicates the a the 3Y will run 4.55 min with the 3s2p A123 pack at full throttle they get 9306 rpm. If I throttle back with the timer to get the 8500 rpm ( approx 9% reduction) would that reduce average current by 9% and increase run time by same, giving 4.95mins?

Best, Dennis

Mike Palko · « **Reply #33 on:** June 21, 2008, 05:41:30 PM »

Hi Dennis,
I can't say for sure if reducing the the throttle 9% will gain you 9% (seems to easy). Have you flown a similar setup at a 9% reduction? If it were me I would want a little more head room for the governor.

If you would like I can plug the numbers in MotoCalc, I can vary the throttle and see the results. How accurate it would be I do not know......

Mike

Dennis Toth · « **Reply #34 on:** June 22, 2008, 09:52:06 PM »

Mike,

It would be a help if you could run first cut numbers in MotoCalc for the NEU1902/3y and 2.5 with the A123 3s2p pack at 8500rpm, APC E 12x5 (which should be around 91% throttle if the NEU calculator has it right). With the AXI 2820/8 the draw down for 6min is 3850mah (38.5amp).

Thanks, Dennis

Mike Palko · « **Reply #35 on:** June 23, 2008, 04:32:44 PM »

Hi Dennis,
The MotoCalc results were not very good. Only the 2.5Y NEU was able to turn the required 8500rpm and it did so at 92-93% throttle. If you see a variable I missed let me know and I will rerun the numbers. You will find the results attached.

Mike

Dennis Toth · « **Reply #36 on:** June 23, 2008, 07:12:57 PM »

Mike,

Thanks for running the numbers, you selected the componets I have. About the only thing that I was surprised at was the motor amps at 51, is that the static or in air amps? I would expect that the actual will likely be <40 so it seems that the NEU 1902/2.5Y for the A123 3s2p is the way to go. This could be interesting.

Thanks, Dennis

Mike Palko · « **Reply #37 on:** June 23, 2008, 08:44:23 PM »

Dennis,
All numbers are static.

Mike

Larry Wong · « **Reply #38 on:** July 06, 2008, 06:57:16 PM »

Mike how much cooling do you have ? I didn't notice if the battery is on top were are the cooling intake and exits and it looks like the ESC is on the bottom cooled by intake scoop for motor.

Mike Palko · « **Reply #39 on:** July 06, 2008, 08:55:38 PM »

Hi Larry,
The cooling air enters through the front cowl opening and exits just in front of and through the scale radiator door. The battery is centered (top to bottom) in the fuselage. The fuselage is very narrow (2" wide battery Vs. 2 1/4" ID fuse) so cooling has been a bit of an issue. I have a lot of ideas on how to improve cooling, it just takes time to put each into effect. Starting with the least invasive.

Mike

Author Topic: Mike Palko's P51 (Read 3783 times)

Alan Hahn

Alan Hahn

Alan Hahn

Alan Hahn