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The rules for any event should be as stable as possible. The
changes in what batteries are available is the only reason at
present for any rule changes in E-36. I fllew the event at the
Nationals and saw no problem with the rules, except for the possible
interuption of availability of the allowed batteries. As a minimal
change, perhaps we should allow any nicad or nmh battery weighing
no more than the present 4-pack of 190s.At the NATS I flew my E-36 in Class A electric with a 4-cell NiMH pack made from KAN400AAA cells: Check them out here: http://www.cheapbatterypacks.com/main.asp?sid=372932&pgid=loosecells&chem=NIMH. The cells and packs are readily available and really cheap. The pack is slightly lighter than the SR190. The performance of the airplane is a little bit better than with the 190’s, but ,of course, still not good enough to compete with the real Class A ships. rivers
Hi All,
Why not allow any nicad or nmh weighing 40 grams or less? This
would permit all packs now in use and would be easy to check since
the CD will always have a scale if the pack is not one everyone is
familiar with. Capacity is not too good a criterion for rules since
it is subject to upgrade, as happened to the N cells, and it would
preclude nmh cells such as the KAN400AAA which generally
rate higher in mah.What say you all?
Chuck,
Here are the weights of my 4-cell packs:
SR190 Nicad 37.6 grams
KAN400AAA NiMH 35.0 gramsBoth weights include a 3 inch, 20 AWG cable and a Deans micro connector. They both meet your proposed 40 gram limit. They both perform roughly the same in the airplane, with a slight edge to the KAN400AA. On static test the KAN400 yields about 10% more RPM, but it’s hard to see the difference in the air.
Does anybody know the weight of a 110 Nicad pack? Can you get to 5 or 6 cells and be under 40 grams? I think a 6-cell pack with a 7.2 volt motor would perform better because of improved motor efficiency.
riversThe weight of an N110AA cell is listed as 8 grams so 5 of them will
just make the 40 grams without connectors. I use bare tabs with
holes for screws so that ought to make it foir a 5 cell pack. The
weight of these cells used to be 7 grams. We should weigh a bunch
to find out. Six of them will definately not make it. Of course, if
a rule change is made, we could adjust it to, say 42 grams to
accomodate the 5×110 pack, if that is what we want to do. The
5-pack of 110s will definitely give more power with most of the
motors we use for E-36.I have a 5-pack of N100AA with a few inches of wire and two light connectors. It weighs 37 grams. A loose N110AA greenjacket I
found weighs 7 grams.I have a 5-pack of N100AA with a few inches of wire and two light connectors. It weighs 37 grams. A loose N110AA greenjacket I
found weighs 7 grams.Chuck,
Cool, now we have 3 packs that will meet your proposed 40 gram limit:
1. SR190 Nicad 4-cell
2. KAN400AAA NiMH 4-cell
3. Sanyo 110 Nicad 5-cell
This gives some choices, so I’m beginning to like the battery weight limit idea.
riversHello Richard,
Two things we ought to do:
1) We ought to measure the open potential and internal resistance
of these three so we have an idea which is best (probably 5 x 110).2) We ought to think of how to propose it to the rest of the forum.
Sincerely,
ChuckYou guys need to be communicating with Vic Nippert and Rex Henson. I think that you are on to something.
Hi Guys,
A bench test of a 4 pack of SR special 150s, which are the same size
as 190s, yielded an internal resistance of 50 miliohms per cell. Some
KAN 400s are ordered — to be tested when they arrive.Jim: How do we reach the people we need to talk to about this rule
suggestion?Chuck
Chuck,
It will be interesting to see your results with the KAN400’s.With my SR190 pack I cannot get as low an internal resistance as you do. See my SR190 Battery Test thread. I get .270 ohms for 4 cells (.067 ohms/cell) vs. your .200 ohms (.50 ohms/cell). I’m familiar with your test methods, so I think your results are accurate. My setup includes 1 Deans Mini connector, 1 Deans Ultra connector, 1 big toggle switch, and about 8 inches of #16 gage wire. I’d be very surprised if these components could account for .070 ohms difference; it’s very unlikely.
riversDick,
The reason you get a higher resistance than I do is that you are
testing standard SR 190s. Mine are SR “special 150s”, which are a
special run of the 190s that Larry made for some client who needed
low resistance more than capacity. I got these when the rule still
called for 150s or lower, and Larry (SRibnek) sent me a certificate
verifying that the capacity was less than 150, i.e., legal for E-36. I
measured it too and came up with numbers in the 140s. These are
great batteries–I hope he makes some more!The KANs haven’t come yet. Maybe when I get back from the
weekend’s bike trip they’ll be at the door.Thermals
ChuckHi Guys,
I tested the KAN 400 cell and it is very good. Weighing only 7 grams,
it has an intermal resistance of only 55 milliohms. This is a figure of
merit of 7×55 = 385 gmo, as compared to 340 gmo for the old Sanyo
470AR. This NMH is 85 percent as good as the best nicad ever made,
is cheap, and therefore its a damn shame we can’t use it for E-36.Thermal,
ChuckAll, consider this. This discussion started over a concern about the availability of batteries. Sanyo 110ma cells are one of the most common cells on the market, and they are cheap. Coupled with the GWS motors that most have settled on ( most common on the market ) the 110ma. cells provide decent power. In my humble opinion the only aspect of E-36 rules worth looking at is the Min. weight of 150g. By restricting wing area and weight we are getting close to a one design event. I have made 4 attempts at E-36. The first 3 attempts came in between 120 and 130g. All 3 proformed well, untill I added the weight to make it legal. The point I want to make is that it is possible to build and fly an E-36 that performs well with the componets that we are currently using. I completly understand the original intent of the class rules, and I support them. I am an Electric flyer that wants nothing more than to see participation increase in all electric events. I also agree with Chuck’s comment about rules being as stable as possible but restricting wing span and weight is too restrictive. Droping the min. weight will increase the proformance, but not enough to change the “entry level” status of the class. I also believe that it will increase the number of participants and the diversity of models. This is a very important issue. E-36 has the potential to have a big impact on the future of Electric Freeflight. It is OK to disagree, but it needs to be discussed. Comments please.
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