SEN 1209 3 May 2008

Table of Contents - SEN 1209

  1. Rubber Lube
  2. A bunch of bom stuff
  3. Biggles on balsa

Rubber Lube

From: Paul Rossiter


Back in April 1 SEN, Ross asked about rubber lubes and mentioned that he was using Sil-Slick (if I recall correctly). The other favourite is Son of a Gun (which is called ArmorAll over here in Oz).

I recently did a comparison of ArmorAll with silicon grease (7000 cs)using 10g Coupe motors from April 07 Tan Super Sport. These were wound (as I would for a Coupe competition) to 30 in-oz and I measured the turns and torque as the motor was unwound (at 4 turn intervals). Four of the motors were taken in sequence from one box of April 07 and two from different parts of a second box.

While the results for the six motors are hardly statistically significant, I found that any possible effect of the different lubes (if there was any) was hidden in the variability of the rubber (particularly that from different boxes), with the possible exception that the silicon grease consistently allowed for about 20 more turns (in about 450), which would give a slightly longer motor run right at the end of the cruise. there was very little difference in the burst and mid cruise.

Has anybody else done a comparison of the different lubes? (I seem to recall that there was one done some time ago in NFFS symposium and also found little difference).



BOM Editorial Comment

SEN is primarily about FAI Free Flight events. Many of our readers fly other events and we publish information about them too. This  current BOM rules decision is about AMA Classes and does not directly concern FAI Free Flight.  It's probably not appropriate that we comment about it in detail. I have read much on other web sites and news groups and am in agreement with Chuck Markos below and others that the BOM rule is the least of our problems.  In reading the material I find it very divisive, discouraging to beginner and confusing to outsiders and not focussing on the more important things. I agree with Gil and Anselmo that some people are clearly capable of building a better models than they can buy, so more power to them. It's good that we have programs for young people to build airplane, that's not incompatible with BOM it just helps get people started at a reasonable cost and goes towards forming a more complete aeromodeller. None of this is a reason to have a BOM

For these reasons I feel that we have presented a number of different points and now the debate should be continued elsewhere.

BOMing out

It appears that those who argue for or against BOM requirements are not familiar with the current interpretation of the rule.  I cannot quote it exactly, but the BOM interpretation requires only that completion of the aircraft requires more than an hour or two of skilled work.  That is, covering of the wing would be suficient to qualify the model.  I would therefore venture that vast majority of the models that show up at AMA or FAI contests satisfy the BOM.   There is really no need to keep the argument going.
Chuck Markos

BOM and AMA gas

Recently Gil Morris posted a message regarding eliminating Builder of Model for AMA events. Essentially, he postulated that elimination of BOM will run off a lot of AMA Gas fliers. I believe he is absolutely correct with his reasoning. Eliminating BOM will most certainly turn AMA 1/2A and A Gas into an event dominated by F1C and especially F1J long wing bunter planes. Larger B and C planes will take a bit longer to dominate, but it won't be a long wait. Fliers who don't already fly these FAI events will not go out and get these planes. They will walk away and fly other events or they will simply not come to the field. By way of proving this theory, we need look no further than the F1J event itself. When it was first introduced, a lot of guys would take their 1/2A Gas planes to the field and fly. 7 secs for 2 minutes in rounds and then a little flyoff. Hey, this is kinda fun. When the long wing bunters arrived a couple years later, the guys with the simple 1/2A planes realized that they could not compete in the flyoff with the LWB planes and simply quit participating. Entries are down. I know of 2 guys who fly locked-up planes in this event. One is stubborn,the other is more stubborn. I love them both, by the way. Now, the event can seldom be settled on the day it is started.

Category 3 AMA Gas and Classic Gas boil down to making a 2 1/2 minute max on a 4 second engine. With a locked-up plane, this isn't really as easy as it sounds. I figured this out pretty quick when I returned to the hobby in 1998. I first did it at the 2006 NATS.I can state that I fully expect to make the first 5 maxes with my planes. I guarantee that Bob Hanford does also. We can both tell you, smiling, that it doesn't always happen. There is a myth about a horsepower race requiring a Nelson or Cyclon engine to compete in Classic Gas. Nelson's weren't on the top podium at this year's NATS and a Cyclon didn't win 1/2A Classic. The most successful AMA Gas plane in the last 5 years is a Satellite with stock K&B engine. No one can take seriously the idea of flying a NosGas plane in either event. Remember that 4 sec for 2 1/2 minutes thing.

I have no delusions about retaining BOM. Its a given that it will go. If not this cycle, then the next for sure. There is a serious effort to eliminate Classic Gas as well. This is in response to dwindling entries in AMA Gas events. The belief is that Classic Gas has siphoned off some fliers. Certainly, it has done a bit of siphoning, but a lot of those siphonees will simply not join the marathon that the LWB planes require. They fly Classic or something else or stay home.

Elimination of BOM is really only going to have a serious effect on ONE event----AMA Gas. No one is going to get serious about building RTF planes for AMA FF events. There is not going to be a huge advantage to the high-tech planes in the other AMA events. AMA Gas will deteriorate to a few diehards flying FAI planes against themselves. It'll take about 3 years. If you guys want to see gas fliers at the field after eliminating BOM, then I would strongly urge you to retain the Classic Gas event. If not, you're not gonna see many fliers. I believe this so strongly that I'll bet a NFFS Life membership on it.

Thanks to all for your patience with my little diatribe.
Dan Berry

BOM the UK angle

Nurse SCAT,

Its interesting to read the discussion on dropping the BoM rule for some US classes. We went through a similar sitiation a few years back in the UK where we dropped BoM for all but scale events, ie for all duration events. I read the comment :-
"If the change allows more comeptitors, then more power to it.". Well the evidence this side of the pond is that it has made little or no difference; you simply don't get lots of additional people buying or brrowing models to compete. You perhaps get a few guys buying models to compete in a few other classes. If the ONLY reason to drop BoM is to induce additional flyers then I think you'll be dissapointed. The problem is that you then can't go back; its a one way ticket.

Best of luck with whitchever decision you go with.


Last Word From Ross

Thank you all for the support of my BOM comments. I would like to address a few points raised in the responses.

My district representative who serves (I think) on the FF contest board sends me e-mails polling FFers in the district when these proposals are submitted. That is how my opinion is represented in these matters. If there is a way to vote directly I would like to know it too.

Larry is right, the BOM is a drop in the bucket. My point is that is someone who manages to get to the CD table at a contest with a model in their hand, overcoming those cultural and geographical barriers we both agree are nearly insurmountable, should not be stopped by a rule that has nothing to do with the primary criteria governing the competition (flight time).

As for John's point that I am getting old, I must unfortunately agree. The scary part is that even though I'm middle aged, I am still one of the youngest guys on the field (when I manage to get to the field).


Re: Just Out - The 2008 BMFA Free Flight Forum Report:

Indoor Wood Selection - Bob Bailey

Here's a little tip that's always worked for me.  Go inside, turn on
the light and close the door.  I find this makes wood selection that
much easier than doing it in the garden, especially if its blowing
half a gale and raining !

-  Biggles

Roger Morrell