ALES competition motor

[Tenderfoot]

The new rules for 1/2A ALES gliders are based on the motor flux ring being 28 x 16 mm. Direct drive and 2S lipo being the limiting factor. (I don't do Nicads) My question is what motor that meets the requirements is the horse for a 30 second motor run? I am building the plane now and want to get the motor on order, but I don't have knowledge to pick the biggest and meanest that fits the rules.

All suggestions will be appreciated.

[Larry3215]

I think you are a little confused. There is no 1/2A motor rule for ALES. If you were looking at the National rules, the notes on 1/2A motors was for a different event - LMR. NOT ALES

For ALES you can use any motor you want.

[Larry3215]

For ALES, the optimum motor is the lightest setup that will give you about 120-140 watts per pound.

Any more power than that is just excess weight.

[Tenderfoot]

There is no question that I can be confused a little or a lot with out any help. My wife has been on that train for 53 years.

So help me out, the rules that I have been looking at are posted on the RC groups under sailplanes. I never figured out who Sticky is, but he seems to be quite knowledgeable. The ALES group seems to have an AMA trial class that anything goes for the airframe if the motor is limited to a flux ring of 28x16mm.

Some of the clubs that have listed events under this header are near enough to me that I would like to give it a go. So, my plan is to build a GL with a few mods put in a motor and see how my new found hobby is progressing compared to others.

So the information that I think I need is what is the biggest, meanest motor (28x16mm) direct drive on a 2S available.

If this isn't what I need, please help.

Regards,

Tenderfoot

[Larry3215]

What you were reading are rules for several different Electric Sailplane contest formats.

The contest that has the 1/2A motor rules is an LMR type of contests. LMR = Limited Motor Run. Its a totally different contest from ALES.

For ALES contests, there are NO motor rules at all. You can use what ever you want. Inrunner, outrunner, big or small, long or short doesnt matter.

Some clubs do have different classes within the ALES format, but they generally focus on the model in some way. Foamies vrs everything else or maybe 2 meter and smaller vrs open class or beginner vrs expert class.

I dont know of anyone who is doing any kind of motor limits in an ALES contest.

Now, with LMR type contests your question is very relevant. LMR contests reward the best motor performance you can get from that size motor. The goal is to get to altitude as fast as possible.

In an ALES contest you do NOT want excess power and you do NOT want to get to the altitude too fast. The perfect ALES launch gets you to 200 meters in exactly 30 seconds. No sooner and no later. if you get there sooner, you are giving up soaring time to your competitors. If you get there late - you are giving up altitude.

So its kind of like Goldilocks - you want your power system not too big and not too small. It needs to be just right

For ALES, that works out to 120-140 watts per pound.

That said, buying quality motors and esc's and batteries will give you lighter components for the same amount of power. So it pays to get good stuff if you want to be a serious player. Weight is your number two enemy with sailplanes. Drag is number one

[Tenderfoot]

Your help is greatly appreciated in sorting out the difference between LMR and ALES. I really didn't realize the difference. However, my question still stands: What is the biggest, meanest motor available for "LMR" 1/2 A rules. I do understand that price makes a difference and I hope that will not stand in the way of the answers.

I thought having a altitude limit switch in the LMR class was the same as ALES.

Thanks for the help.

[Larry3215]

I dont do any LMR and most of the motors I use I have no clue what the internal dimensions are.

Your best bet is to ask your question again only change "ALES" to "LMR". Then yoiu will likely get answers from the guys who play that game. Id ask on RCGroups in the elect sailplanes section.

ALES and LMR are vaguely similar in that they both use electric sailplanes but thats about it. As far as I know, most of the ALES limiters wont work for true LMR events with the possible exception of the Sky Limit device.

The contests are flown very differently and the motors, esc's batteries and planes are very different. The LMR planes are closer to hotliners than thermal ships. Very different contests.

If you build a plane for LMR it wont do too well in ALES contests and vice versa.

[Dr Kiwi]

A 28mmx16mm flux ring limits you to 22mm diameter (or less) stator motors.. so you can use 2208, 2212, 2215...maybe 2216 (like one SunnySky I tested)... but not 2217.
These are several 2215 Scorpion motors.. I'd look at those.

http://www.innov8tivedesigns.com/ind...cPath=21_25_93

They have some 2216 heli motors too: http://www.scorpionsystem.com/catalo...s/hk22/?page=1

[Dr Kiwi]

What size prop are you thinking of for your 2s use? That will determine the Kv required.

[Tenderfoot]

Thank you for the information. I am seriously looking at the Scorpian 2215 driven by a 2S lipo. About the size of the Prop. Since I am not fluent in electric speak -- my plan is to get the 2215 put a folder spinner on it, hook up my watt meter and try everything that I have to zero in on about 26 to 28 amp draw. I realize that this is a bit more than the rating, but my thought is "30 second max run time," the lipo will lose some oomph and I will average out to 25 amps for the run.

Since my thinking is often a a bit like using a screen door on a submarine, does this sound close to arriving at the desired result?

[Larry3215]

That sounds close enough to me

If you had an in-flight logger you could get closer. Some setups actually pull MORE amps as the model speeds up and a logger is the only way to find that out - or seeing the smoke trail behind the model

As long as your Diam/Pitch ratio is well over 1/1 you should be safe enough. Anything above 1.5 should be fine. In other words, a 12x6 prop has a ratio of 2/1 or 2. A 12x8 has a ratio of 1.5/1 or 1.5. Low ratios are more likely to pull more amps as the model speeds up due to the prop being stalled when static.