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Pattern Weight Limit Why?
Hey guys, I am wondering about the weight limit for AMA and NSRCA Pattern planes? I know that in the sportsman class, no one at a regional contest is going to weigh your plane and kick you out for being over the 11lb limit. But at the higher classes, and at the NATS, your plane must be below the limit to be legal. If someone from the AMA or the NSRCA would care to explain the reasoning behind the 11lb weight limit, I would like to hear the answer. It seems to me that with modern electric components, you have about 6lbs of airframe including wheels prop/spinner, and about 5lbs for motor/ESC/Servos/Battery/Etc..... If your plane is heavy it will not perform the same as a lighter plane, but why make the bar so low and restrictive? is it just to drive up the cost? Why on earth would you drive the cost up for everyone? Does not make any sense to me.....
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I agree. I see pilots spending hundreds of not thousands of dollars with carbon fiber parts and expensive in-runner gear drives just to make weight. If the limit was 5.5 kg...about 12 lbs., the cost to fly would come way down.
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Originally Posted by R3d Ryd3r
(Post 12210123)
is it just to drive up the cost? Why on earth would you drive the cost up for everyone? Does not make any sense to me.....
However as you have already mentioned a lighter plane performs much better. But in some cases it does not fly nearly as well as a heavy plane. Seeing as your from Hawaii I am sure you know all about the wind factor. I think as long as you do not plan on going to Nats or at worlds I would say most regional events do not weigh planes. Just go out have fun, meet people and become the best pilot you can. |
Originally Posted by big_G
(Post 12210145)
I agree. I see pilots spending hundreds of not thousands of dollars with carbon fiber parts and expensive in-runner gear drives just to make weight. If the limit was 5.5 kg...about 12 lbs., the cost to fly would come way down.
Originally Posted by R3d Ryd3r
(Post 12210123)
Hey guys, I am wondering about the weight limit for AMA and NSRCA Pattern planes? I know that in the sportsman class, no one at a regional contest is going to weigh your plane and kick you out for being over the 11lb limit. But at the higher classes, and at the NATS, your plane must be below the limit to be legal. If someone from the AMA or the NSRCA would care to explain the reasoning behind the 11lb weight limit, I would like to hear the answer. It seems to me that with modern electric components, you have about 6lbs of airframe including wheels prop/spinner, and about 5lbs for motor/ESC/Servos/Battery/Etc..... If your plane is heavy it will not perform the same as a lighter plane, but why make the bar so low and restrictive? is it just to drive up the cost? Why on earth would you drive the cost up for everyone? Does not make any sense to me.....
I have a BJ Craft Essence that weighs 4860g ready to fly and is a fully competitive airplane in FAI as well as AMA schedules. I also have a BJ Craft Nuance that weighs less than that. These two airplanes do not have a scrap of carbon fiber or in-runner drives. I did splurge a bit though and use a Mejzlik 3 blade prop. I am not the only one....there are many guys that have these airplanes and I would guess that they are all well under the 5kg limit. You would be amazed at how well they fly compared to almost anything else....properly setup though....setup is everything. Dave |
Dave...I was partially thinking on the lines of the initial price of the plane. Most higher end aircraft are designed to be light....Both of my less expensive planes, a Vanquish and Caelus will not make weight (5K), even with the carbon prop and spinner. Now I fly Intermediate, so I have an increased weight limit if I go to the Nats. Many of the guys flying Masters and FAI are using 5,500-5,800 ma. batteries, so they have a tougher time than I do making weight.
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Originally Posted by big_G
(Post 12210161)
Dave...I was partially thinking on the lines of the initial price of the plane. Most higher end aircraft are designed to be light....Both of my less expensive planes, a Vanquish and Caelus will not make weight (5K), even with the carbon prop and spinner. Now I fly Intermediate, so I have an increased weight limit if I go to the Nats. Many of the guys flying Masters and FAI are using 5,500-5,800 ma. batteries, so they have a tougher time than I do making weight.
Personally I have been using F3A-Unlimited Power Unlimited batteries for over 4 years now. I have the 5100mah 35C and they are physically a lot larger and heavier than the 5400mah 25C packs which I will be using this year. These have plenty of power to fly all the Patterns. IMO...we don't need the larger continuous discharge ratings...ie 35C, 75C etc....as the helicopter guys do. We need more capacity but at a lower more constant current draw...so we can get away with a lower C rating and save weight. Dave |
I understand people spending big bucks on high performance lower weight components, they want the plane to perform. What I don't understand is how a heavy plane gives the pattern flyer an advantage? Yes wind is a factor, but a heavy plane is not going to be a significant advantage in light winds, or even in a moderate wind. Just wondering the reason for the restriction.
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Originally Posted by Dave Harmon
(Post 12210155)
Not really......
I have a BJ Craft Essence that weighs 4860g ready to fly and is a fully competitive airplane in FAI as well as AMA schedules. I also have a BJ Craft Nuance that weighs less than that. These two airplanes do not have a scrap of carbon fiber or in-runner drives. I did splurge a bit though and use a Mejzlik 3 blade prop. I am not the only one....there are many guys that have these airplanes and I would guess that they are all well under the 5kg limit. You would be amazed at how well they fly compared to almost anything else....properly setup though....setup is everything. Dave http://www.rcuniverse.com/forum/atta...mentid=2161094 |
I have a 2 meter Vanquish (@$750.00 not counting shipping), an inexpesive motor (Tacon 160 @$56.00 not counting shipping) that is powewrful but heavy, and the servoes are various Hitecs high voltage high torque and an Airtronics radio. The whole plane ready to fly with batteries (2 Zippy Compacts, 25C, 5000mah @$45.00 each) is slightly under 5KG. It can be done. I am flying Intermediate, but I have seen several Vanquish planes in Advanced, and at one contest saw someone fly Masters and placed.
Sheldon |
Originally Posted by Smooth Pilot
(Post 12210205)
I have a 2 meter Vanquish (@$750.00 not counting shipping), an inexpesive motor (Tacon 160 @$56.00 not counting shipping) that is powewrful but heavy, and the servoes are various Hitecs high voltage high torque and an Airtronics radio. The whole plane ready to fly with batteries (2 Zippy Compacts, 25C, 5000mah @$45.00 each) is slightly under 5KG. It can be done. I am flying Intermediate, but I have seen several Vanquish planes in Advanced, and at one contest saw someone fly Masters and placed.
Sheldon |
If you set the limit to 5.5kg someone will whine about it not being 6kg.
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Originally Posted by rgburrill
(Post 12210292)
If you set the limit to 5.5kg someone will whine about it not being 6kg.
I think the 5kg limit came about a long time age, before electric. Glow engines are much lighter than equivalent electric systems, especially when you factor in the weight limit for glow is without fuel. |
Originally Posted by R3d Ryd3r
(Post 12210189)
I understand people spending big bucks on high performance lower weight components, they want the plane to perform. What I don't understand is how a heavy plane gives the pattern flyer an advantage? Yes wind is a factor, but a heavy plane is not going to be a significant advantage in light winds, or even in a moderate wind. Just wondering the reason for the restriction.
Originally Posted by R3d Ryd3r
(Post 12210202)
So the Essence is a 2M Plane made by BJ-Craft. At $2200.00 its not exactly cheap, and the cost to outfit the plane with new components from F3A-Unlimited WITHOUT the Transmitter and SHIPPING is around $4000.00 I know there are more expensive birds out there, and that this is a great airplane, but I'm just wondering if making the 5000g weight restriction is the reason the sum of the parts are so costly.
http://www.rcuniverse.com/forum/atta...mentid=2161094 (edit....because of the way you worded your above comment....I assumed that you did not include the cost of the Essence...."cost to outfit the plane". Motor $560 Esc $150 4 servos about $110 each Replacement hardware about $50>$75 depending on choice Spinner Falcon $70 Prop...the most expensive 3 blade is about $150 Motor mount about $50 4 sets of batteries about $800 for the good stuff Misc stuff glue etc...$50 Total $2345 not counting the radio. I don't get you thought process.
Originally Posted by rgburrill
(Post 12210292)
If you set the limit to 5.5kg someone will whine about it not being 6kg.
Originally Posted by big_G
(Post 12210331)
Most everyone could meet 5.5 kg using standard quality/priced components....
I think the 5kg limit came about a long time age, before electric. Glow engines are much lighter than equivalent electric systems, especially when you factor in the weight limit for glow is without fuel. Of course....E-power does not have the vibration problem so everything can be built much, much lighter....this includes the hardware, linkages and all other stuff. I have not mentioned the additional weight of glassed surfaces and painted wings and tail, adjusters and more glue and structure. Electric planes don't need most of that stuff.....except paint...of course paint is just preference by the builder but most painters don't know when to quit...including me. One other thing that I was told a long time ago....'no one flies inexpensively.....you can minimize the cost but flying is always expensive.' And.....you get what you pay for. Dave |
The 11lb limit comes from the FAI limit for pattern of 2x2M max size & 5Kg max weight
Quite a few years ago there was also a 10cc (60) engine limit. There were calls at the time to have an unrestricted engine capacity limit to lower the cost of pattern as the 10cc engines were becoming quite specialised for pattern & therefore expensive. If the engine size was unrestricted then cheaper but higher capacity engines could be used. Well engine capacity did become unrestricted, so did that lower the cost ? - NO it had the opposite effect and we got larger capacity Specialised F3A engines that were even more expensive !! IMO if the weight limit were increased then a similar effect would occur and cost would increase - I can imagine, for example, if a weight limit of 6Kg (13.2 lb) was allowed then we could get super “bloated” BiPlanes with full 2M wingspans and exotic/super expensive power systems to drag them around the sky.... Steve |
Thank you Dave and Steve you saved me a lot of typing! In any competitive event the participants will push for any perceived advantage to the limit of the rules. We have seen displacement grow from .60 to 1.20, 1,40, 1.60 1.70 and now 1.85 with CDI and several versions of more complex soft mounts all at higher cost and complexity. And no one will compete with just one engine. We have also seen simple brush-less motors grow to complex gear or belt drives and even counter rotating systems.
It is counter intuitive but fewer limits gives more room to increase cost and complexity. Rules are part of any competition and one must always be keenly aware of the unintended consequences of changes. |
Originally Posted by SAB
(Post 12210421)
The 11lb limit comes from the FAI limit for pattern of 2x2M max size & 5Kg max weight
Quite a few years ago there was also a 10cc (60) engine limit. There were calls at the time to have an unrestricted engine capacity limit to lower the cost of pattern as the 10cc engines were becoming quite specialised for pattern & therefore expensive. If the engine size was unrestricted then cheaper but higher capacity engines could be used. Well engine capacity did become unrestricted, so did that lower the cost ? - NO it had the opposite effect and we got larger capacity Specialised F3A engines that were even more expensive !! IMO if the weight limit were increased then a similar effect would occur and cost would increase - I can imagine, for example, if a weight limit of 6Kg (13.2 lb) was allowed then we could get super “bloated” BiPlanes with full 2M wingspans and exotic/super expensive power systems to drag them around the sky.... Steve But now I think we have the opposite problem, with Electric power the inverse is true, the less expensive power plants (or Motors) that are built to produce around 2500 Watts tend to be heavier than the expensive F3A type motors that are on the market. Batteries have the same inverse relationship, the cheaper the battery, the more it tends to weigh with the same capacity. (debatable I guess but it seems that way to me) and if you want to scratch build a 2M size plane out of Balsa and Ply, you will have a tough time keeping it under the weight of 5000g with same running gear that is recommend for top performing composite ships. If that is the answer, that back in the Glow Fuel Days the displacement of the engines was a concern, and keeping the weight below 5000g was the goal to discourage bigger and bigger power plants, I can see that. I think the rule is archaic and should be amended to reduce the cost and simplify the construction of a pattern planes that are more and more using Electric power. R3d |
R3d,
Actually when engine capacity was 10cc there were no 2M or 11lb planes, they were typically around 65" wingspan and 7-8lb. The unrestricted engine capacity rules (to allow use of cheaper engines !!) drove the size and weight increase of planes to the 2M & 11 lb limit !! Increasing the 5kg limit would IMO escalate the cost once again, as I said previously. Now,for all but the highest class you don’t need a full 2M plane. The Sebart MythoS 125 is a great example (there are others) - almost 2M size at 1.9M and 1/3 the cost of the MythoS Pro, flies great on 8S with either a Hacker or Motrofly $200 motor. I’ve seen this model also do very well on 10S with low cost motors. Steve |
Originally Posted by SAB
(Post 12210421)
The 11lb limit comes from the FAI limit for pattern of 2x2M max size & 5Kg max weight
Quite a few years ago there was also a 10cc (60) engine limit. There were calls at the time to have an unrestricted engine capacity limit to lower the cost of pattern as the 10cc engines were becoming quite specialised for pattern & therefore expensive. If the engine size was unrestricted then cheaper but higher capacity engines could be used. Well engine capacity did become unrestricted, so did that lower the cost ? - NO it had the opposite effect and we got larger capacity Specialised F3A engines that were even more expensive !! IMO if the weight limit were increased then a similar effect would occur and cost would increase - I can imagine, for example, if a weight limit of 6Kg (13.2 lb) was allowed then we could get super “bloated” BiPlanes with full 2M wingspans and exotic/super expensive power systems to drag them around the sky.... Steve Should the powers that be bump up the weight limit to 5.5 or even 6 kilos, either the valley view or DLE 40 cc twin on pipes will easily haul the mail. And these engines are so light there is little reason to be heavier than 5.5 kilos. On pipe, output is close to 5 hp and will turn 22x8 or 9". Neither of these power plants are expensive and are simple to operate and maintain. Of course, there are those that just love to spend their money....okay with me. |
Originally Posted by Dave Harmon
(Post 12210372)
I think there is a general thought that the heavier and larger the airplanes are will drive up the cost because the thought is that they will require larger engines/motors and the associated larger amounts of fuel....either liquid or solid. Also...there is a size restriction....which goes hand in hand with the weight....ie...can't make E-planes much lighter than they are today unless the size is reduced or a new material and new techniques come along.
I can't imagine where you are getting those cost numbers from. (edit....because of the way you worded your above comment....I assumed that you did not include the cost of the Essence...."cost to outfit the plane". Motor $560 Esc $150 4 servos about $110 each Replacement hardware about $50>$75 depending on choice Spinner Falcon $70 Prop...the most expensive 3 blade is about $150 Motor mount about $50 4 sets of batteries about $800 for the good stuff Misc stuff glue etc...$50 Total $2345 not counting the radio. I don't get you thought process. Agreed....totally! Glow airplanes....especially 4 stroke powered must be built to withstand the pounding of the engine...so that makes the empty airframe weigh a lot more. Of course....E-power does not have the vibration problem so everything can be built much, much lighter....this includes the hardware, linkages and all other stuff. I have not mentioned the additional weight of glassed surfaces and painted wings and tail, adjusters and more glue and structure. Electric planes don't need most of that stuff.....except paint...of course paint is just preference by the builder but most painters don't know when to quit...including me. One other thing that I was told a long time ago....'no one flies inexpensively.....you can minimize the cost but flying is always expensive.' And.....you get what you pay for. Dave |
Hi Matt......I always read your stuff so I am familiar what your preferences are.....sounds like a good use for those Griffins.
Whatever happed to the Syssa deal? From some of your posts and other info I read indicated that it was a good handling engine purposefully designed for model airplanes but needed more development due to being a bit low on power. I had been wishing for a decent gasser to be available but then the E-power came on and that was that. Dave |
Dave,
The Syssa 180 is a decent racing engine. Loves to rev. I tried detuning it to turn reasonable loads at decent rpm but it just wasn't optimal. My current choice for the past roughly 5 years is the GT33. Turns the same props as the 185 at the same or better rpm. Best of all is the mid range torque which rivals the YS. And on the light Griffin, I use 1/3 throttle to 1/2 for verticals. 8 ozs lasts 15 minutes, no fib. There are a few guys in France flying the RCGF32 and report good results with that one. I've not tried it so can't say definitively. It's only 250$ or so. And Ron Mc is running an EME35. There are several inexpensive choices. These are simple sport engines no different than the OS160FX, except they are on steroids and perfect for pattern |
Sounds good Matt.
Perhaps some of the guys entering Pattern will see this and realize that your above description is definitely competitive. The best thing is that instead of $30 or more for a gallon of hard to get fuel.....all they gotta do is head to the local and buy a gallon of gasoline! Wait till them guys get a load of the sticker shock on a 4 sets of decent batteries....HAW...but they will last hundreds of flights. Dave |
But how does the gas engine do in sound pressure test? That is also controlled in major events and in my experience the gas engines are much louder than the YS or electric. I may be wrong about this... :)
By the way, build up surfaces tend to be lighter than full composite surfaces. The fuselage may be the opposite case - full composite ones can be lighter than balsa/ply structures. I sort of agree that the weight limit could be lifted a bit to make it easier to get an ARF 2m pattern kit under the limit. For example, my Spark Evo 2 is some 200 g overweight at the moment which is mainly caused by the motor which weighs about 670 g with prop mount and mounting hardware. This motor works just fine and delivers more than enough thrust and costs only about $150. It will be replaced with a Hacker C54 which is 170 g lighter (and considerably more $$$) soon... However, making the 5 kg (or 5050 g) limit is not the only reason to change: A lighter plane will fly better and the motor is higher quality and will last for hundreds of flights. There may be other bonuses as well like easier throttle management and better braking etc. It will also cool directly from the built in air scoop of the Spark without carving the spinner cone full of holes. :) |
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Hello
Matt I totaly agree with you. the most economical pattern is to make yourself as labor is not counted, with gas engine. Sometimes weight is upper 5 kg. But in France serie Nat A and B (equal advanced and master) limit weight is 5,5 kg. Finn "A lighter plane fly better" ! I'm not sure, tank full or empty ; fly is the same with about 500 g difference. Claude On these patterns engine is RCGF32 very cheap ! http://www.rcuniverse.com/forum/atta...mentid=2161344 |
Originally Posted by FinnSpeed
(Post 12211090)
But how does the gas engine do in sound pressure test? That is also controlled in major events and in my experience the gas engines are much louder than the YS or electric. I may be wrong about this... :)
By the way, build up surfaces tend to be lighter than full composite surfaces. The fuselage may be the opposite case - full composite ones can be lighter than balsa/ply structures. I sort of agree that the weight limit could be lifted a bit to make it easier to get an ARF 2m pattern kit under the limit. For example, my Spark Evo 2 is some 200 g overweight at the moment which is mainly caused by the motor which weighs about 670 g with prop mount and mounting hardware. This motor works just fine and delivers more than enough thrust and costs only about $150. It will be replaced with a Hacker C54 which is 170 g lighter (and considerably more $$$) soon... However, making the 5 kg (or 5050 g) limit is not the only reason to change: A lighter plane will fly better and the motor is higher quality and will last for hundreds of flights. There may be other bonuses as well like easier throttle management and better braking etc. It will also cool directly from the built in air scoop of the Spark without carving the spinner cone full of holes. :) Any electric only plane can be converted to gas or glow. I don't buy that these models are built too lightly. On the contrary, we have been duped by the mfrs that IC planes must be beefier. Well, the Griffin was an eplane which I converted. I put it on a diet during the conversion, removing unnecessary weight such as landing gear blocks and plywood firewalls for lighter and stronger alternatives I designed. The model with a full tank of gas is about 10# 2 ounces (4600 grams). That's light enough. And if I wanted even less weight, I could build a new set of wings and stabs from balsa as I am currently doing for my Delta. Weight savings, even all paint, is considerable at about 100 grams per panel for wings and 25 grams per panel for stabs. But since the Griffin is just an ARF and is plenty light, it just isn't worth the effort. one thing certain, flying a really light plane will spoil you. Even 8 ounces difference is something you feel in the air. I also don't buy that a heavier model flies better in the wind.....my Temptress and now the Griffin, both at 10# or less, simply damp faster in wind. Neither plane is small....both are two meter types with well over 1000 sq inches of wing. Oh yeah, almost forgot....Temptress is 14 years old with at least 2500 flights; she is in deserved retirement. LOL! |
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