Mike Freeman

Hi Denis, This is a useful table for comparisons.. https://www.spektrumrc.com/Content/Media/PDF/SPM_Transmitter_Comparison.pdf HTH, Mike

Hi Phil, No, the DX6e isn't obsolete. It is a brand new Tx which came out at the end of last year. It is available in DSMX only in Europe and DSMX/DSM2 elsewhere in the world, as discussed above. It is an entry level Tx which, some say, will replace the DX6i but I think it is so close in spec to the DX6 that a lot of newcomers will hop straight onto a DX8 when they get bitten by the bug, potentially making the DX6 obsolete! Mike Edited By Mike Freeman on 01/03/2017 07:42:14

Point taken Phil, thanks. However, the DX6e is neither G2 or G3. It is a first generation tranny which only has a single (but adjustable) antenna.

The DX6e transmitter has a single diversity antenna - there is no antenna in the handle. The single vertical antenna is adjustable so it can be set to an angle to suit how the Tx is held. I think the diagram Denis is referring to is on page 45 of the English portion of the DX6e's manual which looks to be a generic clause on safe distances from the aerials for all Spektrum Txs. Denis is correct, the DX6 has dual diversity but the 6e is definitely single. For what it's worth the single diversity antenna on the DX6e has never caused me any concerns. The antenna fades count I see on the telemetry are always within the normal range of 50-100 per flight.

If I may please put the case for the defence... Spektrum are a global player and the DX6e is available in DSMX and DSM2 modulation so, technically, my Datafile table is correct. My understanding is the DSMX only label applies to European sets only, DSM2 is still available elsewhere in the world. In hindsight, I can see a reference to this in my review would have been helpful so my apologies for that, During my research I came across the document at the bottom of this post which states that DSMX and DSM2 Tx's and Rx's are both ways compatible (I have enlarged the relevant part just in case the text pixalates too much). From the posts above this appears to be not the case and I know that David has spoken to Spektrum about this and they have confirmed this document is wrong. I imagine David will be clarifying this point in the next issue of RCM&E. With regards to Maurice's comment on the statement in Model World, I don't read this magazine myself but, looking at the Traplet website, I see they ran a review of the DX6e in their Feb issue. It could be their reviewer made the same assumptions as me and listed the modulation as DSMX/DSM2 and their comments in the March issue are a similar correction. Modulation aside the OP asked if anyone had any experience of the DX6e. Well, I think it is a very capable set with lots of features for a reasonable price! More detail can be found in my review in the March issue of RCM&E. Thanks, Mike

Posted by Robert Hynes on 16/01/2017 12:43:46: Just wanted to say thanks to Mike Freeman for this article on parallel charging. As a result of reading it I went straight out and bought two paraboards and will be buying more. I particularly enjoyed the detail in the article and the technical account of the risks. I currently have three electric aircraft with four LiPos each. The fact that I can now charge all twelve packs in less than an hour will change my life. I do agree that safety is paramount and will be writing a reference article in Aerobase in the near future crediting your article as the source Mike. When that is finished I will post a link to a new thread on the ModelFlyingForum here for input. Again thanks, I really enjoyed the article. Bob Hynes. Thanks Bob, I'm glad you found the article useful and thanks for your kind comments. It's great to hear you've had a go at parallel charging and are enjoying the time saving it offers. I'll swear my packs are also better balanced since I've been parallel charging! My exploits are very much at the club flyer level but, from some of the posts on here, it looks like there is some serious parallel charging going on out there! Some very interesting reading. The principles are the same, its just the size of the equipment that changes! Cheers, Mike

Posted by Trevor Crook on 20/12/2016 23:12:21: Yep, I disregarded serial charging as soon as I got to the second part of the article. Thanks Trevor, That is how I intended the article to be read..... Introducing the reader to the two options of multiple lipo charging - quickly dissing the Series option, saying there is a better option.. "Parallel" charging and going into the detail. I know there are folks that prefer series charging but the only benefit I can see is the individual measuring of each of the cells voltage in each of the multiple packs. The limitations on number of packs a charger can charge and risks of incorrect connection, as described by Bryan, are not worth the hassle IMO - parallel charging is the way for me! As Martin says above, a faulty balance plug would not be picked up with parallel charging and you are quite right in your post above that this would be picked up when checking the charge state of the packs to be parallel charged. Parallel charging is safe to do as long as we are vigilant, treat the Lipos with respect and follow the golden rules! BTW the Paraboards are good value for money and save the hassle of knocking up a homemade set of leads. I could do a similarly detailed article on Series charging if there was a demand but I think most will agree that Parallel charging is the better option!!

Thanks for the feedback Bryan, I wanted to describe the series charging option as it is a legitimate method of charging cells. If I had just talked about parallel charging with no reference to series I wouldn't have been giving readers the whole story. I agree that series charging isn't ideal and I say this in the article calling it "the least favourite option" and "pretty restrictive". I also raise the points/concerns you eluded to ie the states of charge and capacities of the packs. You mentioned the risk of a short circuit in the balance plugs. There are balance connectors commercially available that allow the balance plugs from two individual packs to be joined to make a single pack so this is a recognised method of connecting packs. Series charging is only mentioned early on in the article and, I thought, having described the principle and rubbishing it early on would help readers focus on the much better option of parallel charging that followed. I'm sorry if you disagree. The rest of the article is geared around parallel charging, Indeed, the title uses the word "Parallel" so I'm confident your concern of someone skim reading the article and ploughing straight into series charging is pretty unlikely. Whenever I skim through a document I usually read the Conclusion first and it gets my full attention. I'm sure I'm not alone in this practice and the first two words in my Conclusion are "Parallel charging". Anyone who did skim through the article and had a mind to give it a go would surely go back through it in detail. I know I would! I hope this puts your mind at rest, Regards, Mike

Here is the drawing I mentioned above....

Good evening All, I thought I would share a bit more info on my review of this little beauty! Especially how I managed to hide most of the gear inside the profile fuz. Here are some photos that didn't make the final article which hopefully show the details.: The final radio layout under the canopy After boring the cable routes though the fuz I cut the sides out to make room for the LiPo. The cut out is slightly smaller than the LiPo to "grip" it when inserted. I have found this works fine without needing any velcro. That bit of the fuz side was thinned down to cover the LiPo once inserted. Here the ESC is being drawn into the nose through the battery access. I have found no problems with the ESC being buried like this, no signs of overheating. The Lipo just before being connected and pushed into it's EPP crevis. The thinned down EPP side piece hides it from view. I hope that gives you a bit more info. When I find out how to upload a pdf I'll add a drawing of the fuz to show a bit more detail. Cheers, Mike

Posted by PatMc on 20/12/2015 17:45:14: Mike, the thrustline is only relevant when refered against the angle of attack. In level flight your model will have some AoA depending on how fast it's going. The thrustline when refered to level flight will vary by the same amount. I prefer to control the climb rate by manual adjustment of throttle & elevator in most models though I'm not averse to using some Tx mixing with, for example, some E-gliders. I don't follow your comment "I find elevator compensation doesn't work particularly well on electric models. It might be ok at the start of the flight but as the power falls off towards the end of the flight the compensation becomes overpowerin Hi PatMc, my experience of elevator comp on an electric model was with an electric glider kit - no names! but it had a terrible tendancy to balloon up when the throttle was opened. Wing and thrustline on the same longitudinal line but no down thrust. I programmed in some elevator comp (lets say 3mm of down elevator with full throttle). This worked fine and stopped the ballooning at the start of the flight when the battery/motor were producing maximum thrust but then, as the battery wore down and the thrust reduced, the 3mm of down elevator was too much for the lower thrust and, as a result the model dived down. Elevator comp will work on an oily lump with constant thrust (until the tank empties!) but even then, introducing down thrust is the "proper" solution. Edited By Mike Freeman 1 on 20/12/2015 18:00:24

No worries Martin. Going back to Franks OP I think downthrust is required to compensate for both the drag of a high wing model and the increase in airspeed. The TABOO has a mid position wing with the wing and motor almost on the same longitudinal line - no significant thrust/drag moment. My downthrust is mainly required because of the extra lift generated from the semi symmetrical wing as the speed increases. Had I built the model with a high mounted wing and done the same experiment I'd bet the downthrust would have been slightly more. I agree with Martin's comment above, trying to fudge the design by introducing elevator compensation to do the job of the downthrust isn't the right way to go about it.  It's far better to balance the aerodynamics and thrust lines to achieve self compensation.... especially on an electric powered model! Edited By Mike Freeman 1 on 20/12/2015 17:15:58

Yes Martin, that is my point - no matter what throttle I use there is no change in pitch. The 2degs downthrust I arrived at via experimenting achieves the self compensation you mention. I don't like models that balloon up when the power is applied and the above post was my way of making sure it didn't happen by adding downthrust. Obviously, the time honoured way of fitting washers behind the motor would have achieved the same effect but the nose of the TABOO wouldn't have worked with washers!

I find elevator compensation doesn't work particularly well on electric models. It might be ok at the start of the flight but as the power falls off towards the end of the flight the compensation becomes overpowering. Even on sports aerobatic models with semi-symmetrical sections and/or models with high wings I think down thrust is beneficial and I always add some to my designs. When I designed the TABOO (electric sports aerobatic model - free plan Feb 2012 RCM&E) the semi-symmetrical wing and tailplane were set at zero-zero and I built a profile fuz with an adjustable front former so the thrust angles could be adjusted. I then did lots of flying trying different CofG positions and thrust angles (down and right) until I found a set up I liked. The end result was 2degs down and no right thrust. The original is still flying a treat, when the taps are opened there is no change in pitch right from the launch until the end of the flight. These photos should give you the idea. 1/64" ply shims were added/taken away until I was happy - then I built the proper fuz to these angles.

Since I finished the review in the Aug 2015 issue there have been a few more tweaks.. Those who have read my blurb will have seen I was surprised there was just one servo controlling the ailerons. Well, in the interest of experimentation I have swapped the single for a servo per wing. this has removed a little bit of double neutral I was getting and allowed a bit more differential to be added plus some camber changing and adding spoileron air brakes. The model flies fine as it is - out of the box but these mods have made it better.. This first photo shows the original bellcrank and the replacement Ripmax SD100 servo which just fits. The existing cut away for the bellcrank is just big enough! The next photo shows a close up of the servo. I had to cut the pushrod outlet shroud off but turned it over and stuck it in the slot under the pushrod. I cut a slot for the servo lead which follows the route of the original pushrod outer and stuck some white insulation tape over the top. The servo lead exits through the original pushrod hole which needed to be enlarged to get the wires through. It was necessary to pull the wires out of the plug to thread it through. The hole in the side of the fuz had to be opened up slightly to allow the plug to get inside the fuz where it plugs into a fly lead - one channel per wing. This mod has allowed me to increase the differential. I now have 18mm up aileron and 9mm down. I also fly it with about 80% up aileron as spoilerons and no elevator compensation is necessary. This makes landings much easier. I also mix in some flaperons with about 3mm up flaperon for aerobatics and inverted. That undercambered wing is always going to struggle with aeros but this mod has certainly made a difference! Even after quite a bit of airtime the EPO "living" hinges are still a bit tight so I freed them up by carefully sanding the EPO down with some sandpaper wrapped around a bit of 1/16" balsa sheet. Do this carefully and keep holding up to the light to check the thickness and it does the job.. Finally, I have been tweaking the CofG back bit by bit. The furthest I have gone is 58mm at the root but this makes the model neutrally stable. Put it in a dive and it will stay there! I find 56mm about right - slightly behind the review point. This made the elevator a bit sensitive so I have dropped the throw to +/-6mm. Moving the CofG like this means I have been able to remove the 10g weight that is pre-fitted in the nose!! The end result of all these mods is an additional 5g in weight but a more enjoyable flying experience which wasn't that bad originally to be honest!! You can't stop a Tweaker tweaking!! Edited By Mike Freeman 1 on 11/07/2015 18:04:35 Edited By Mike Freeman 1 on 11/07/2015 18:07:02