"Guidelines Discussion"

Here's the place to talk about "Light" electric combat limited to Open designs with brushed motors.

Moderator: hbartel

gunfighter
Posts: 860
Joined: Tue May 28, 2002 12:32 pm
Location: USA

"Guidelines Discussion"

Post by gunfighter »

Mark - You never cease to amaze me! The new subject areas are great!

OK. I'll start off the new area with a question.

We have now flown several heats of E-combat across the country, so what is working for you? What guidelines (not hard and fast rules - yet) would you like to see imposed during the "experimentation period" so we can stay on the same page on a national basis? I'm sure many of us will have E-fighters at Paris next month so it would be good to have some general guidelines for this first "event".

This thread refers to what is being called "entry level", "semi-scale" or "WW2 E-fighters". Let's leave the "open" discussion for another thread if we can.

I'll start it off:

Planes should be a "semi-scale" replica of a fighter or fighter / bomber aircraft flown in WW 2. Single or multi engine aircraft are allowable.

I think 32" has been determined by default as the maximum wingspan. I like this span as they are easy to see, and very aerobatic. so - how about 32" max wingspan. OOPS! How about twins? Say 40" to start with?

Most of the planes I have seen and read about are somewhere between 8 and 12 oz. Do we want to set a minimum weight to increase wing loading and prevent "furballs"? I think yes. I'm thinking around 10 - 11 oz. Maybe 12 - 13 oz for twins?

By the same token do we want to impose a maximum wing area also to establish a wing loading and prevent furballs? I propose 220 square inches maximum. When someone builds a twin they can post their recommendations for wing area.

Batteries - I don't think there is much difference of opinion here? 7.4V systems (2 cell LiPo or 6 NiMh or NiCad)

Power systems - AAHHH!! here is the BIGGIE!
Some say brushed / geared systems only. Others want brushless (including outrunners) included. I, personally, don't see any difference in running a brushed or brushless system AS LONG AS THE SPEED IS MAINTAINED AT AN EQUAL LEVEL!
I have a proposal for that. We are all used to taching before matches and between rounds. so -
impose RPM levels determined by the pitch of prop used. i.e. -

3 P prop= 12,400 RPM
4P prop= 9300 rpm
4.7 P prop= 7910 rpm
5P prop= 7440 rpm
6P prop= 6200 rpm
7P prop= 5320 rpm
8P prop= 4650 rpm

all of these yield a pitch speed of 35.2 MPH(+or-)

I know, some will say that props can be modified, but that has not occurred in other "RPM restricted" classes to date so why worry about it. If someone is caught cheating......

OK, lets hear some other opinions.

Understand - these are just GUIDELINES we are discussing at the moment. Hard and fast rules can wait a little longer IMHO!
slam
Posts: 834
Joined: Wed Sep 05, 2001 8:14 pm
Location: USA

Post by slam »

sounds great gun.

i think wing restrictions are critical. 32" seems to be popular. i do think we have to put a max sq", i have been building mine to scale and i think that is the difference in perfomance from others. if i make it more "scale-like" and enlarge the wing i will get better performance with a lighter wing loading.

min weight is important also, i'm leanin on the heavier side to allow for mediocre building of newbies. like ssc, you will need to be right on the minimum weight for a competitive plane. i would like to see at least 12oz. i can build lighter but give up some added strength to do that. my 12oz zero on gws b flies fine. no killer loops so furballs would be improbable.

i think prop specs and rpms will be mandatory. sounds like a good place to start.

slam
drewjet
Posts: 1101
Joined: Fri Mar 16, 2001 5:24 am
Location: USA
Contact:

Post by drewjet »

Sounds like a great start to me.

I agree on 32" max wingspan
minimum weight of 11 to 12 ozs.
I like the prop RPM Rule. but you need to calculate for a 4" and a 5" prop as I am using them currently.
I think a max wing area around 200 to 220 will help limit the looping ability.

Drew
wparmenter
Posts: 597
Joined: Tue Mar 13, 2001 9:18 pm
Location: USA
Contact:

Post by wparmenter »

So far these parms sound good. The only thing I can see is that different props perfrom differently than expected for a given rpm. I remember trying electric for ssc and thought if an 8x3 turning 17500 was good then an 8x6 turning at 8750 would perform the same. It did not. the 8x6 would barely fly the plane. Using the same motor and higher voltage, the 8x3 performed similar to the slimers and rpms were comparable. Just a point to keep in mind if a certain combination turns out to be best.
Cajun
Posts: 2020
Joined: Wed Mar 28, 2001 10:22 pm
Location: USA

Post by Cajun »

Chuck, the ideas are all OK except the taching and RPM levels. Checking props and taching is just too cumberson. AND, I am sitting here looking at a grey prop from BP that has NO size markings on it. How is a CD to handle this problem.

Lets limit the motor size and the RPM and speed will take care of itself. Trying to limit the power of a too powerfull motor is self defeating and destined to failure. Ever wonder why NASCAR does not allow 454 cubic inch engines in Winston Cup racing[?][?]

One aspect that needs to be addressed is <b>NO 3 CELL PACKS IN AN INDOOR SETTTING.</b> Letting these planes get too fast indoors with spectators and other participants is inviting the AMA to come in and set severe setback limits, safety lines, hard hat requirements, etc just as they did for all size gassers. This would immediately <b>KILL</b> any form of indoor E-combat. Using 3 cell packs outside will still, in all likelyhood, require the setback limits of half A. In the interest of trying to keep this simple and out of the reach of burocratic(sic) involvement, it might be advisable to limit all E-combat to a max of 2 cells.
boilermaker
Posts: 100
Joined: Thu Sep 02, 2004 9:10 pm
Contact:

Post by boilermaker »

I like the 32", 11-12oz, 220 sq inches, and 7.4v.

I think Pitch and RPM is inefficient to enforce, and if fully enforced, not effective. A 10" 3 pitch prop at 12,400 will whip a 5" 3 pitch prop at 12,400 and somebody could find the right winding to hit it (even if it makes their plane spin 12,400 with the prop standing still).

I know people are trying and using different power systems. The more open it is the more expensive it will be to have a top system. If power systems are limited to the point of being near spec or even full spec, what is the drawback? I can see positives (things stay cheap, its easier for someone new to know what to buy right away, managing events is simplified, and we can just sit back and fly instead of constantly thinking about what to fly.

My 2¢
wparmenter
Posts: 597
Joined: Tue Mar 13, 2001 9:18 pm
Location: USA
Contact:

Post by wparmenter »

Boiler, you have some good points. A spec motor might be the way to go, but brushless is getting cheaper and cheaper every day. It would be a shame to be limited to brushed only. But at $9 for a brushed geared setup, thats hard to beat, and is essentially disposable. If someone is going to cheat, they will find a way. A spec brushed motor would be difficult to modify other than the timing and a good break in. Hmmm. So much to consider.
gunfighter
Posts: 860
Joined: Tue May 28, 2002 12:32 pm
Location: USA

Post by gunfighter »

Drew - I calculated for the 4 and 5P props and edited the original post.

Cajun - I did address batteries and proposed 7.4V systems only. 2 cell LiPo or 6 cell NiCad or NiMh.

<blockquote id="quote"><font size="1" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote">A 10" 3 pitch prop at 12,400 will whip a 5" 3 pitch prop at 12,400 and somebody could find the right winding to hit it (even if it makes their plane spin 12,400 with the prop standing still).<hr height="1" noshade id="quote"></font id="quote"></blockquote id="quote">
ROFLMAO[8D] Now THAT would be funny to see!
But, seriously, could it be done with 2 cell @7.4V? and with the obvious increase in amp draw, could it fly for 3 - 5 minutes? If so, while thrust would increase wouldn't the top speed (pitch speed) still be limited?
I'm really fishing for ideas - let's hear some more!
User avatar
boiler
Posts: 3336
Joined: Wed Jan 01, 2003 8:16 pm
Location: Ohio
Contact:

Post by boiler »

We had indoor combat last night again. I was the only "experienced" combat pilot. We had 5 slow sticks in the air at ounce and had a blast. I was the only one using the stock brushed motor. Everyone else had brushless, most including myself had 2s but some had 3s batterys. I found that because of the slow stick flight charactistics, and the limited space in the gym, I didn't feel at a disadvantage. This is a spec arf airplane that has spare parts available and any non-builder can put one together. After 2 years of begging club members to try combat without results, I had 4 friends in the air with me having a great time. I hope to get them to the Havoc or Muncie to see the adrenilen rush of ic combat. I may get someone to spar with me when the weather breaks. I could build a couple of wings or give them a couple of beaters. The slow stick exceeds the 32 inch "standard" which I do agree with for non speck plane meets. I think there is more room to grow e combat amoungst the non-combat community with a slow stick speck class. Just my $.02
catboater
Posts: 19
Joined: Tue Jan 04, 2005 12:33 am

Post by catboater »

I can agree with everything except the minimum weight. There are about 10 of us flying here in the Seattle area and nobody has an airplane over 10 ozs. I'm flying both FF and slab EPP with GWS 350's and a small bl. If you require us to add weight you'll do nothing but turn ok airplanes into dogs.
Please explain to us newbies why all of you feel the need to weight down our airplanes. We believe that a heavier airplane increases inertia and thus midairs become catastrophic. Lighter airplanes have a better chance of simply bouncing off and continue flying.
I shouldn't say "we believe". We KNOW it to be true because we've seen it several times. Heavier=more carnage.
I say foget min. weight. Restrict batteries and possibly come up with a prop or rpm rule like Gunfighter is suggesting.
drewjet
Posts: 1101
Joined: Fri Mar 16, 2001 5:24 am
Location: USA
Contact:

Post by drewjet »

Catboater, I fully agree with you that weight=destruction. However also low weight=furball=destruction. If we set a minimum weight, everyone will build to the low side of it as has been seen in SSC. If a guy has a 9.5 oz plane and the minimum is set to 10, I don't think that .5 oz will make a large difference in impact damage, but instead of adding lead he adds .5 ozs in reinforcements he will have a much more durable plane.

Drew
User avatar
Which_way_is_up
Posts: 1637
Joined: Tue Feb 12, 2002 8:54 am
Location: Dallas, Texas

Post by Which_way_is_up »

Gentleman,

Just taking a moment to reflect on the "purpose" of this thread. As the title says this is just a "discussion". No rules will be created tomorrow, or next week, or next month as a result of anything discussed here. Ideas discussed here most likely will end up as rules eventually but this is a time to "explore" the possibilities of this new area of combat not try and cram your way of thinking down someone else's throat. We are getting new members to the RCCA that are coming on board because of the exciting things they are seeing from the electric world and the RCCA's attempt to come up with some form of electric combat. But they're not necessarily familiar with our rather aggressive "discussion" style and can be very quickly put off by it. I've seen it happen already over on another electric forum. Where enthusiast RCCA members have "aggressively discussed" the right way of doing things only to have some folks "unsubscribe" to the thread and lose a potential future RCCA member.

Talk friendly![:D]

<b>"Only criticize by contributing"</b> I believe that I stole that from Leonardo da Vinci
gunfighter
Posts: 860
Joined: Tue May 28, 2002 12:32 pm
Location: USA

Post by gunfighter »

Catboater - It's not just a matter of weight, it is wing loading that we are trying to control. We have seen destruction increase tremendously, especially in SSC, as planes got lighter wing loadings and are able to turn and loop much tighter. Open B planes are heavier and faster but do not get into as many "furballs" and have not seen as much destruction on a round by round basis. Scale and 2548 are also faster and heavier than SSC but are more of a pursuit class due to a higher wing loading. I hope this explains my / our concerns.[?]

It is Possible that a lower weight may be needed for the FF planes because they have no airfoil and can not support the extra weight.

It might be interesting if someone would build a FF with a simple undercambered airfoil and see how it would do.

Roy - I don't think that will happen here as we don't have one dictatorial hard headed non-RCCA individual making rules and bad mouthing the RCCA simply to sell his product![:0] Enough said - I will not bring it up again.[B)]
gunfighter
Posts: 860
Joined: Tue May 28, 2002 12:32 pm
Location: USA

Post by gunfighter »

BTW - I think the slow stick, especially with ailerons, would make an excellent "spec plane" for indoor combat. We have flown them here for quite a wile. The only problem we had was cutting ribbons and getting ribbons tangeled in gears. We went to a single ply of toilet paper about 6 ft. long and it helped a lot. Limit them to 2 cell packs and go have fun.
This (IMHO) would be the absolute best entry level class and could be flown year round![:)]
Lee Liddle
Posts: 3330
Joined: Thu Jun 20, 2002 10:30 pm
Location: USA

Post by Lee Liddle »

As Roy stated, we are just disscussing things here, not making any rules or "outlawing aything.

Cat, here is the argument for a weight minimum.
1) It allows planes to be built with cheaper slightly heavier materials and electronics so that high tech/ high cost is not needed to compete.

2)When combined with a Maximum wing area rule , it puts a limit on how light the wingloading can get. Light wing loading flys better, but there will always be a guy or two(like me) who will sacrifice durability for performance and will bring one plane per heat to a contest.

3) It will reduce the ammount of midairs by reducing the turning ability of the planes, thus opening up the furbal. Same number of planes in a larger space equals less midairs.

4) More airframe weight can be used to build srtonger planes, so that when a midair does happen, the results are better.

Those are all good reasons, but I would not want to make a rule that made slab winged planes totaly uncompetitive. I will, when the time comes, push for a lighter Minimun weight for slab wingged planes, as much as 2z lighter than airfoiled planes. That could achieve all of the goals of the Min weight, while keeping all of the designs reasonably competitive.
Post Reply

Return to “"Light" Electric Combat”