ORIGINAL: J Lachowski
ORIGINAL: nonstoprc
From Lachowski's weight change petition posted on AMA Site:
''here is currently a very limited number of choices of internal combustion motors available for pattern use. Increasing the weight limit by 200 grams will allow for the inclusion of various gasoline motors with the added impact of reduced operational costs that gasoline affords over methanol based fuels. In addition, the increased weight allowance will give electric flyers increased choices in available battery technology and motors. The trend in battery technology is a higher “C” rating with heavier weight. There is a very limited number of choices available in lighter battery technology that meets current needs. Increasing the weight limit will allow for the use of the heavier higher “C” rated batteries. This too will have the added impact of reduced operational costs. The weight restriction for Sportsman should be removed since it is a provisional class where most Contest Directors opt to eliminate or modify the weight requirement to encourage participation. These changes will allow flyers the ability to have a broader choice of airframes if they choose. With these changes, airframe choices will no longer be limited to pattern specific designs at all levels except F3A. In addition, the need for expensive carbon fiber spinners and props will be at the pilots option instead of being an expensive requirement with airframes that are marginal in making weight under the current rules. Gasoline engines have been proven to be a viable option by some people already ,but it requires some creativity(machining, etc,) to get the weight under the current rules.''
My understanding is that
1. 20c 5s 5000mah packs have been on market at least for 5 years and the pricing trend is steady and even downward. The choice and availabilitybof of such batteries are plenty;
2. Carbon fiber spinners at knock-off price are available on the market;
3. Expensive F3A spinners, whether carbon fiber or aluminum, are built with extra features, such as cutouts for forced ventilations, or short in height thus help meet the 2m rule;
4. Other than being lighter, carbon fiber props are much more rigid and durable than those made with traditional material. There is actually a cost saving using a carbon fiber prop over long run for extra benefits;
5. Techniques/tricks exist to trim off extra weight to meet the current weight rule, from existing planes WITHOUT $$$, as documented in this and other threads.
Seems that the reasons to have a weight increase, at least from E-power perspective, are not adequate?
Unfortunately, there are people on this thread who think, otherwise. I don't, but there seems to be enough out there that do. Don't forget the size limits and noise limits are still there. We will still continue to fly the same size airframes. Just because some people can afford the more expensive stuff to make weight, dosen't mean everyone else can.
In my book, 20C packs are marginal for our use and are only really good for about 75 flights tops before they degrade. I'll bet you in time there will not be any 20C packs out there. It is obvious that most manufacturers are not as much concerned as they have been in the past to make lighter packs. Thre are maybe a couple 20C packs out there that I consider light enough to meet the current rules with ease. All the rest are heavier.
Yep, techniques and tricks are there but many do not have the time or resources to make use of them.
Cost savings with carbon props. It just takes one strike of the ground and that blows that out of the water.
Let people have the flexibility to do what they want. If they want to fly a heavy plane let them. There is no significant advantage to the extra weight in my book. My justification may not be as strong as it could be, but so be it.
Everyone has an opinion. Mine is let more people play and lower the resistance to getting there. I have nothing to gain from the proposal I put up. I will still continue to fly a plane under 5kg and do whatever it takes to get there.
Joe,
I do not know about you or others but one of the top FAI pilots in my club uses 3300mah per P11 or F11 with his 20C packs. I have been using the same 20c packs as his for my class, with Neu F3a + CC 80 ICE HV. The max current drawn is around 80A, 20% less than the max current a 20C pack can deliver. To me, 20C is plenty and any extra discharge capability => extra weight.
For the two cases of over-weighted planes we studied in this thread, one is 2oz over and the other is at the mark of the 5kg + AMA allowance. Cost-effecitive tricks definitely exist to trim a couple oz off and both pilots do not object suggestions. In my opinion, there is no need to spend $40 dollars to get it done.
I just worried that there may not have prevalent number of way over-weighted planes to begin with. So if most of these planes are 1-2 oz over, why not recommend some easy solutions, and instead ask for a rule change?
If the same argument comes up next year, will we recommend another round of weight limit increase again?