RE: RX LiFe's left connected is OK???
Actually if there is any device drawing current then no battery should be left connected for a long period of time. LiFe's are can be ruined by discharge to zero, especially if held at zero for a period of time. Example - some of the newer Rx switches are fail-safe which actually draw current when in the off position. This is a very small amount of current but a drain none the less. LiFe batteries such as the A123 for instance have been ruined by folks that have left their batteries plugged in during the off season without use or cycling while installed in these fail on systems. Best of luck John
Posted on: 4/19/2012 6:39 PM by Author "john4648" in the forum "Batteries & Chargers"
http://www.rcuniverse.com/forum/fb.asp?m=11049204

RE: TBM Shock Jet
Wires?
Posted on: 3/22/2012 7:15 AM by Author "john4648" in the forum "RC Jets"
http://www.rcuniverse.com/forum/fb.asp?m=11010503

RE: Dual LiFe Packs Question
Ok guys. I am using a Schottky Diode 45V 15A in a TO-220 Case like this: http://search.digikey.com/scripts/DkSearch/dksus.dll?WT.z_header=search_go&lang=en&site=us&keywords=497-2753-5&x=0&y=0 Data Sheet: http://www.st.com/internet/com/TECHNICAL_RESOURCES/TECHNICAL_LITERATURE/DATASHEET/CD00000819.pdf Now this is overkill (there are a bunch of technical reasons for this selection though) but for $.99 I dont care. The 1N100X series is too light in my opinion. Does not matter if you insert it in the + or - lead of the source. However be consistent. What I do using the A123 26650 cells is lay the diode between the cells. After soldering leads to the diode on the bench, use super glue to attached the diode to the mid side of the cells. Also super glue the diodes leads to the cells, so there can be no movement of wires. Then I use heat shrink over the entire pack. GL John
Posted on: 1/3/2012 6:41 AM by Author "john4648" in the forum "Batteries & Chargers"
http://www.rcuniverse.com/forum/fb.asp?m=10889224

RE: Dual LiFe Packs Question
Ed, Have been running dual A123 packs in my Jets and Pattern planes for several years. Always use diode isolation. Never had an issue. Have never tried dual A123's without diode isolation, would imagine that with the very low internal resistance of the LiFe (or any of the Li cells) that if you were to develop a very low ohm short across a cell that you would in very short order drop the pack voltage of the good pack. Perhaps with more than a little heat. Do not wish to find out! GL John
Posted on: 1/2/2012 11:21 AM by Author "john4648" in the forum "Batteries & Chargers"
http://www.rcuniverse.com/forum/fb.asp?m=10887906

RE: TBM Shock Jet
Steve, Tough question, they are all good turbines. I personally have flown the SJ with a Wren 54, Jetcat P70, and a K80. Personally from[i] my perspective only[/i], the Kingtech Kerostart is the way to go. This because they are such a good value. I think the importer is running a Holiday Special at this time so you are able to save even more than normal compared to the other turbines. BTW I personally will not buy any new turbines that are not Kerostart. They all run well, seem to last and have good service (have used service on all three Jet Central, Kingtech and Jetcat) Now having said this the Jetmunts VT80 (Dreamworks) is interesting. Installation is so simple with just a Turbine and the Pump along with a battery. But have not held or seen one run, so just throwing it out there. GL John
Posted on: 12/26/2011 12:00 PM by Author "john4648" in the forum "RC Jets"
http://www.rcuniverse.com/forum/fb.asp?m=10876846

RE: Dual Switches
Blake, Heard to know without them in front of me, but a guess might be that one is the RX lead the other a charge lead? John
Posted on: 11/27/2011 1:50 PM by Author "john4648" in the forum "Batteries & Chargers"
http://www.rcuniverse.com/forum/fb.asp?m=10831578

RE: S9074SB Servo
Bax, Apparently I did not communicate well. In the servo specs "BLS" is used.The "BLS" is NOT used in the descriptors at the bottom of the page. Does this mean that this servo is brushless? What type of motor is in this servo? Maybe that would be the more appropriate question Thanks John
Posted on: 11/22/2011 9:57 AM by Author "john4648" in the forum "Futaba Radios Direct support forum"
http://www.rcuniverse.com/forum/fb.asp?m=10823951

S9074SB Servo
Servo motor type question: on the Futaba website http://www.futaba-rc.com/servos/sbus.html the S9074SB servo is described as "2BB, BLS, MCC, MG, WP" does this mean this SBus servo has a brushless motor? Thanks John
Posted on: 11/19/2011 9:57 PM by Author "john4648" in the forum "Futaba Radios Direct support forum"
http://www.rcuniverse.com/forum/fb.asp?m=10820288

RE: KingTech K-80
Joey, I think you all ready know this but just in case, Futaba throttle needs to be reversed at the Tx. Then go through the Tx calibration procedure for ECU. GL John
Posted on: 11/19/2011 9:14 PM by Author "john4648" in the forum "RC Jets"
http://www.rcuniverse.com/forum/fb.asp?m=10820252

RE: Modelbau MB339 buildout
Nice work Dave, Did you by any chance save templates of the formers, etc you have made. I also have the MB339. Looks like that would save some effort in my construction effort (not started yet- still in the big box). Thanks John
Posted on: 11/14/2011 7:14 PM by Author "john4648" in the forum "RC Jets"
http://www.rcuniverse.com/forum/fb.asp?m=10812463

RE: Whats the lipo or A123
The A123 is, at least at this point in time, a unique animal. It is not specifically Li ion nor is it LiPO. Rather it is a version of LiFe that A123 calls Lithium Nano Phosphate. They can be ordered from several vendors such as Duralite https://duraliteflightsystems.com/index.php?_route_=batteries/duralite-plus-a123 or can be obtained from Dewalt packs such as http://www.ebay.com/itm/DeWalt-DC9360-R-H-Duty-36V-NANO-Battery-Pack-WARRANTY-/350360259285?pt=US_Power_Tools_Batteries_Chargers&hash=item5193194ad5 (just an example many more are listed). There are 10 cells in the Dewalt pack. Black & Decker had a line called VPX and each battery pack contained two of the smaller 1100ma cells. This line was discontinued some time ago though there are still some packs floating around. When searching for cells beware the standard LiFe is not the same as the A123 cell. The charged voltage of 2 A123 cells is 7.2V vs 8.4 for two LiPO's. Lightly loaded the A123 2 cell voltage drops to 6.6V which is pretty close to a 5 cell NiCd pack of about 6.25V. Hence why we are not running regulators. You will probably not need the regulators with the A123's. Loosing the regulators simplifies as well as rids the craft free of another failure point. On my 2.4G pattern craft I assemble the plane at the field and plug the batteries in direct to rx. They remain plugged in until I disassemble the plane to go home. After flying about 8 flights each pack needs about 250ma to top it off. These are the 1100ma cells, the smaller ones. No need for switches either. Eliminates another failure point... this is just what I do - no recommendation here. You will have to draw your own conclusions, yes? All the best John
Posted on: 11/13/2011 11:12 AM by Author "john4648" in the forum "Batteries & Chargers"
http://www.rcuniverse.com/forum/fb.asp?m=10810013

RE: Whats the lipo or A123
I have used A123 exclusively for several years now. Do not fly the large ignitions but do fly jets. The A123's have several advantages, first is no chance of fire if abused or mistreated. Second can be recharged in as little as 15 minutes. Third they seem to last forever. Forth no regulator is normally needed, with [i]most[/i] receivers/servos made today you may power the airborne electronics directly. Fifth cost is relatively low at about $10 per cell (26650 2300ma), two cells per pack of course. I have a set on the bench (electronic test bench) that have over 3500 cycles (APR18650M1-A 5 amp charge/2 amp discharge). Now they have not failed however they are down to 50% of stated capacity and 60% of actual original capacity. Normal recommended use is to 80% of stated capacity. This was still over 1000 cycles. Probably more life than you are experiencing with the LiPO batteries. The industry is getting better producing LiPO's all the time. The C ratings of the LiPO's far exceed the C rating of the A123 which is really only important if using the different chemistry for propulsion. The A123 have to managed differently. The charge cutoff voltage is different. Balance is not as critical when the cells are newer but becomes an issue as the cells age, so they do need to be balanced. A123's like LiPOs do not like to be discharged to zero volts. The A123's will take it maybe once or twice but each time capacity/life is reduced. (dont ask me how I know...). I always use two packs in parallel, two switches and the packs are isolated with high current diodes (low volt drop). That way if a pack fails, voltage drops or shorts it is removed from the circuit. Good Luck John
Posted on: 11/13/2011 6:56 AM by Author "john4648" in the forum "Batteries & Chargers"
http://www.rcuniverse.com/forum/fb.asp?m=10809631

RE: JetJoe OWNERS thread
Yes, I have a JJ1400 call me for details 402-525-6111 or j@neb.rr.com John
Posted on: 2/14/2011 5:52 PM by Author "john4648" in the forum "RC Jets"
http://www.rcuniverse.com/forum/fb.asp?m=10336534

RE: The new Tornado sport jet
Hello Rich, Have used the S-Bus in several jets. See attached pic of a CompArf Flash. One cable out of receiver thats it. Just aft of the main board and just above the three airline disconnects is the single lead going to the aileron and flap servos in the wing. Works BUT I am not sure long term of any benefit that is not out weighed by added risks. Like the good news is there is only one lead going to the receiver, thats also the bad news no redundant leads. Can plug batteries in anywhere in the chain but then how do you service them? Then there is the use of multiple leaded octopuses to get the signal down line. Y harnesses are loathed by most users. I make mine own so feel some reassured that they are made up properly. Have for the most part used the decoder setup rather than the S-Bus servos. Very irritating that Robbe Europe has a decoder capable of driving four servos when we in the states can only get decoders capable of driving three servos. That four device decoder would be nice for wings. Jury is still out. After we get a couple hundred flights on one install we can talk again.... John
Posted on: 1/14/2011 7:49 PM by Author "john4648" in the forum "RC Jets"
http://www.rcuniverse.com/forum/fb.asp?m=10264357

RE: TBM Shock Jet
Thats what I came up with as well Ken. Not very far in front of the neutral point. Interesting and not good for stability. I am flying at at 3/4" in front of manuals balance point. Or let me rephrase, when the 8 inches of snow sublimates so we have I runway again I will be flying.... Will try CG at 3/4" and also about 1" forward as well see how it handles. Flying about 1/2" in front of the manual's CG now. Inverted flying is OK. Then perhaps the spin test. But then this is my last SJ so maybe not.... Generally there is some latitude on these more stable platforms. The small stabilizer concerns me. Maybe someone more learned can expound on all of this and the correlation to possible elevator stall with a more forward CG and a smaller than normal horizontal stab area? Perhaps we can turn a pretty good airframe into a really good one... John
Posted on: 1/14/2011 4:08 PM by Author "john4648" in the forum "RC Jets"
http://www.rcuniverse.com/forum/fb.asp?m=10263862

RE: TBM Shock Jet
Hi Ken For some reason a lot of pictures are no longer showing up on RCU. Perhaps it is just me but I have no pictures on your old post. At any rate the rear of my tank is 6.75" from the wing leading edge. The CG as shown in the manual is 5" from the leading edge so with full fuel I am nose heavy which is OK. CG check should be performed in the configuration which would make the planes CG the most rearward which in this case is empty fuel in the main tank. An interesting task, follow this link http://adamone.rchomepage.com/cg_calc.htm and enter the measurements from you setup. Then compare the calculated CG found to the CG as specified in the build manual. See a difference? I did. Let us know what you find. Also interesting the horizontal stab, on most designs, normally runs 20-30% of the wing area. The SJ horizontal stab area is about 15% of the wing area. The reason I bring this up is because of the SJ's nasty spin characteristics and because of this where you might want to place your CG. Disclaimer - No I am not an aero engineer.... Best of luck John
Posted on: 1/14/2011 10:17 AM by Author "john4648" in the forum "RC Jets"
http://www.rcuniverse.com/forum/fb.asp?m=10263016

RE: TBM Shock Jet
Hi Ken Conventional wisdom says balance the plane with UAT full, main tank empty. Am running the Kevlar Jettech tank. My tank is located forward of the recommended CG so the CG moves aft as fuel is burned. Which tank are you using and where is it located? John
Posted on: 1/14/2011 6:31 AM by Author "john4648" in the forum "RC Jets"
http://www.rcuniverse.com/forum/fb.asp?m=10262507

RE: TBM Shock Jet
Currently the SJ has a JetCat P70 (P70 just came back from JetCat for new bearings and ECU repair), but this same SJ has seen a Jet Central Super Bee II and a Jetjoe JJ1400. All flew it just fine. Kind of use the SJ as a test bed for the smaller turbines. Currently I am about an inch in front of the recommended 1 1/2" forward of the gear with the wing on. In other words 2 1/2" in front of the front edge of the landing gear with the wing on. UAT is full and main tank is empty. Keep moving the CG forward in hopes that if I forget (likely) and put the SJ in a spin that I might be able to get it out before it impacts terra very firma. Half an inch forward of recommended was not enough... John
Posted on: 12/20/2010 10:48 AM by Author "john4648" in the forum "RC Jets"
http://www.rcuniverse.com/forum/fb.asp?m=10207952

RE: TBM Shock Jet
Very similar to mine, right at 15# depending on which turbine it has in it. Just a thought might consider keeping the CG towards the nose, perhaps even farther than the recommended. The plane is not CG sensitive to the nose and a little forward might help if you enter the dreaded spin.... again just my sentiment. John
Posted on: 12/20/2010 9:40 AM by Author "john4648" in the forum "RC Jets"
http://www.rcuniverse.com/forum/fb.asp?m=10207841

RE: TBM Shock Jet
Use the Hanger 9 "Digital Servo & Receiver Current Meter" http://www.hangar-9.com/Products/Default.aspx?ProdID=HAN172 tells you how much current the servos are pulling. If not much more than the at rest current of the servo with no linkage attached I let it go. If the servo is being loaded as indicated by the current draw I investigate and correct. Holding the flaps up against natures gravity will need a little current but if pulling several times more than the unloaded current than there is a binding issue along with gravity. Using the current meter a few times and rapidly you will acquire an understanding of what is workable and what is not. Hope this is helpful. Happy Holidays John
Posted on: 12/19/2010 2:28 PM by Author "john4648" in the forum "RC Jets"
http://www.rcuniverse.com/forum/fb.asp?m=10206617

RE: JetJoe OWNERS thread
Have a JJ1400 that am getting ready to list. Complete full autostart. Has new combustion chamber, NGV etc. Serial #606. Thinking in the $900 range. email me at j@neb.rr.com if interested.
Posted on: 12/17/2010 4:55 AM by Author "john4648" in the forum "RC Jets"
http://www.rcuniverse.com/forum/fb.asp?m=10202202

RE: TBM Shock Jet
Think Gerry might be working on something [:D]....will let him expound though [;)]... John
Posted on: 12/13/2010 7:15 AM by Author "john4648" in the forum "RC Jets"
http://www.rcuniverse.com/forum/fb.asp?m=10194075

RE: TBM Shock Jet
Limeybob, I have one of your Jetmach60's it is a wonderful flyer! and will come out of a spin [:D]. Problem is for a lot of folks is construction. Most just do not have time, space or the skills perhaps to construct the Jetmach. I have looked and looked at your Super sport. Would really like to have one - - - - built [:D]. Would purchase it in ARF form if it were to come that way. Have several boomerang style jets but sure get tired of putting the plane togther each time I fly. The booms, outer wing panels, horizontal stab, and all the leads.... gets old. Could get a trailer and leave it all together but covenants will not allow for parking/storing a trailer. If you could just get your line going in ARF form...I would be pretty happy! Others might too?
Posted on: 12/10/2010 9:42 AM by Author "john4648" in the forum "RC Jets"
http://www.rcuniverse.com/forum/fb.asp?m=10188461

RE: TBM Shock Jet
Sad SJ is no longer being carried by TBM. Perhaps there is a "new version" by MFJ? If not then maybe some other company will import the SJ. Is not TBM also changing their direction? Might relate to why TBM is no longer interested. If Hinshaw is around, he could probably shed some light on this. Happy Holidays to all John
Posted on: 12/10/2010 6:52 AM by Author "john4648" in the forum "RC Jets"
http://www.rcuniverse.com/forum/fb.asp?m=10188110

RE: What and when did an rx battery fail on you
About 40 years ago when I was flying Logitrol lost a couple NiCad rx packs Gould as I recall. Switched to GE and at that time cured the issue. No problems since that era. Have been flying only A123 for several years now. Always redundant packs. Diode switched in case a cell shorts or a pack goes flat quickly. Never seen an A123 fail in any way other than capacity loss. Have an 1100 two cell A123 pack that currently has over 2200 charge/discharge events (1100 cycles Chg 5A/Dis 2A Bench endurance test OMG China A123s) and has lost about 20% of its original capacity. Amazing cells. BTW the 1100mah batteries that came from the now discontinued Black Decker VPX packs are known for poor spot welds. I always solder mine however I am on and off quickly with a gun. Always make sure you balance a newly assembled A123 pack. Cells seldom are well matched from the initial onset. This includes cells from new sources such as OMG in China. I have a number of cells from them and they are not well matched (initial charge state) at the onset. After the initial balance they hold balance remarkably well over a long period of time. Sorry a simple question was asked but having read some of the posts I felt more information might be helpful. And no I represent no one... John
Posted on: 11/30/2010 5:25 PM by Author "john4648" in the forum "RC Jets"
http://www.rcuniverse.com/forum/fb.asp?m=10168071

RE: Boomerang Nano!!!
Interesting electric retracts. How are they holding up for them? How many flights? Flying off turf or hard surface? What are they doing for wheels and brakes? Thanks John
Posted on: 11/28/2010 10:58 PM by Author "john4648" in the forum "RC Jets"
http://www.rcuniverse.com/forum/fb.asp?m=10165874

RE: TBM Shock Jet
Like using this fitting when going from 6mm to 4mm http://dreamworksrc.com/catalog/product_info.php?products_id=97 Cheap and simple without doubling up on tubing which works OK as well. Safety wire this, if you wish, to be sure there are no air links or if on the pump outlet side that high pressure will not separate it - not that the pressure could the tubing is a pretty tight fit. John
Posted on: 11/27/2010 11:30 AM by Author "john4648" in the forum "RC Jets"
http://www.rcuniverse.com/forum/fb.asp?m=10162553

RE: TBM Shock Jet
Has anybody put the SJ in a spin, a developed spin, and recovered? If so at what point is your CG? Also did you do anything special to recover? Thanks John
Posted on: 11/22/2010 12:04 PM by Author "john4648" in the forum "RC Jets"
http://www.rcuniverse.com/forum/fb.asp?m=10151868

RE: TBM Shock Jet
My experience has been that an indication of a stall does not necessarily mean a spin. When I see the SJ start to drop or dip a wing at slow speed, I put the nose down to gather speed again. I do a lot of vertical climbs which end with the nose up close to stall position but I just push over and get out. The two spins I have had were intentionally entered from slow forward flight the plane stalled then sticks full deflection. When the sticks were neutralized the spin continued. Nothing and I do mean nothing would stop the spin, including full throttle and application of flaps. The spin appears to be too flat with no airflow over the tail. We joked about balancing the plane with a pound of lead attached to the fuselage at the rear with a release attached to a servo so that it could be jettisoned (or allowed to shift forward) in a spin to make the plane very nose heavy and get the nose down to get some airflow over the tail. BTW the CG I am currently flying with is a good inch forward of the recommended CG, my hope is that if I do get into a spin unintentionally the CG might be far enough forward to let me get out of the spin. Although I do not want to test it! The CG on the two planes that spun in were on the recommended CG. Gets pretty expensive to do the flying for the spin testing, especially if one dings a turbine. Even considered removing the turbine and adding an electric setup -pusher -instead. Still would break the airframe but thats cheap compared to the turbine. Would think there has to be a setup, CG, that would allow spin recovery. But how far forward is the question? Like the plane but will move on after the current SJ is re-kitted. Too much worry to keep on flying the SJ. John
Posted on: 11/22/2010 10:35 AM by Author "john4648" in the forum "RC Jets"
http://www.rcuniverse.com/forum/fb.asp?m=10151649

RE: TBM Shock Jet
The SJ I am flying currently has a P70 that seems to perform quite well. Advertised at 17.5# but seems like more. The SJ weighs 14.5# empty and contains the Jet tech tank. On take off climbs at a steep angle goes until I stop it. Seems almost from takeoff the plane will do unlimited vertical. Never thought about turning it down - other than using the left stick. Lot of the flight time is less than full throttle. Getting about 9 min with about 1/4" left in main tank, includes taxi out and back adding perhaps 1.5 to 2 minutes of additional run time. Do not bother with a ground run tank on this one unless the field is really busy and the takeoff might get delayed. Also ran a Super Bee II in the prior SJ. Pulled the SJ just fine but of course not like the P70. Verticals were pretty much unlimited after a couple of minutes clicked off on the timer. Seems most of the flame outs I have had, and they have been very few occurred just after takeoff. Nice to have the excess power to get quickly through the worry zone. John
Posted on: 11/20/2010 8:58 PM by Author "john4648" in the forum "RC Jets"
http://www.rcuniverse.com/forum/fb.asp?m=10148406