Ed Emmons

mred,

After reading you message I have several questions.

1 You list the motor as a KD A22-20L who is the manufacturer?

2 Is this motor the same as the 28mm x 29mm and 200watts listed in the lower portion of your message?

3 The Tuurnigy Plush 25A ESC. Who is the manufacturer?

4 Can I use niMH batteries in place of the LiPo's? I don't want to get into LiPo's yet. Cost is msjor concern.

5 Espirt models. Could not find an address. Location and tele #

6 Where is Hobby City located? telephone #?

7 I get about 6-8 climbs??? Do yoou mean 6-8 launches per battery cycle?

8 How is the motor attached to the nose of the glider. Motor mount or bolt on thru the first former?

Last question. Where are you located? I live in East Granby, CT and fly in Simsbury, CT. East Granby is about 13 miles north and west of downtown Hartford. I have been retired 14 years. Just returned to RC last year after a 35 year hiatus.

Ed Emmons

mred

Yep, that's the one. It's a 28mmX29mm motor and it puts out around 200 Watts. It's a nice motor and I think it's made by KD, but I am not sure. Everything can be bought at;
http://www.hobbycity.com/hobbycity/store/uh_index.asp

LiPo's are not that much, but you can fly with Nemh if you really want to, but you are going to be a little heavy with those in there. LiPo's don't cost that much at Hobby City. You can get a 2200mah for around $20.00 or so. The only problem is waiting the two weeks to get your order as they are in Hong Kong, but they are good people to deal with. You can cut your battery weight almost in half going with a LiPo.

As for how long I can fly, I get around 6 to 8 climbs per change, with some pretty good times between climbing if I catch a good thermal. I land early so as not to run the battery down to much. It is best to stop at about 80% use with a LiPo for longer life time. I could get more, but like I said, I like to land early just to make sure I don't run the battery down to far. It takes me about 10 or 15 seconds to climb up and then I start looking for thermals. I normally get around 45 min. flying time per charge and I have gone longer, but I am still learning to fly a glider. I have a Spirit 100 that I am building right now, but I still like my Vista a lot. I'll probably take both to the field with me. I'll look up the address for Esprit Models, as I don't have that address just now. My computer crashed and I lost everything.

I live in Georgia about 75 miles from Macon. It's kind of flat here, so I can't slop soar around here. Thermals are pretty good though. Esprit has Groupner folding props and I like them. You can use just about any folding prop, I just like Groupner.

Ed

P.S. OK, here is the address for Esprit Models.
http://www.espritmodel.com/index.asp...S&Category=615
You can order from them, or from your local hobby shop. I just order from the web because I have so far to go to the local hobby shop. It's a 40 mile drive for me and I don't like driving that far just to get a couple of thing I need. I normally buy from them if I am there, but I don't like making a special trip there.

Ed Emmons

mred,

I'm seriously considering your advise about using LiPo batteries. How big is your pack? How many cells and output voltage. What brand of charger are you using? Name and model

Many thanks,
Ed Emmons

mred

I'm using a 2200mah LiPo and you can get one at a very good price from Hobby City. Lang Max is a good battery or you could get the really good ones. Zippy-R are about the best I have found anywhere. Any 3 cell pack will work fine. As for the charger, I am using a Triton 2, but any charger that can handle LiPo's is fine. I use a Yuntong smart balancer from Hobby City too. It works great and is cheap. It will handle 1 to 5 cell packs and balance them while you are charging. You hook the balancer to the balance plug and the charger to the discharge leads and I run mine at 1C for charge. I need to buy another charger so I can charge more then one battery at a time. My next plane is going to have two batteries in it and I don't want to have to wait to long to go fly again. Hobby City has some good chargers, so you can look around there for one. Take care.
Ed

Ed Emmons

mred,

Thaks for the quick reply on batteries/chargers/etc.

Weather here has been beautiful. Hope to get some stick time in the next few days.

Ed Emmons

mred

I have been flying all winter. We seldom get bad weather here for flying, but we do get a few days in the winter that are not so nice. It's nice to be able to fly almost year round. Take care and hope you get some good flying in with the new system. Just take it easy for the first couple of flights. It will want to loop on you with full power, so you have to feed in some down elevator to hold the climb right. With a LiPo battery and about a 200W motor it will be much lighter and with more power it will climb like mad. Take care.
Ed

cbatters

Thx for great info. Working on a BL upgrade to an old 550 can powered 2M glider.

rubberducky

mostly we take a 28xxx BL,
because the next class 30xxx or 35xxx are to big and weight more than 70gr (that is to much)

perfect ...
AL-2836
28 x 36 mm
67 gr
14-18 A
220 W
1120KV

3s LiPo 1800mAh and a 25A ESC
8x6-9x5

cbatters

I have seen a lot of posts where people say you need to run a 10 or 11" propellor on a 2M glider. Are you losing a lot in terms of efficiency by spinning a small propellor?


Clint

mred

I use a 10 or 11 inch prop on mine to load the motor to the high end of the constant amp limit so I get the most out of my setup. Most of the time I use a 10X6 and a KD A20 22L 200W motor and it pulls a 2M glider up almost vertical and I have used an 11X6 on some to go above the max constant a little. I can pull 25A for 60 seconds on the KD motor and not hurt it, but most of the time I use the 10 inch and keep it in the constant amp range. I don't see that much difference in the climb between to two props, but I never went for anything smaller. The bigger the prop you can turn the better. With the 11 inch prop I pull 23A and with a 10 inch prop I pull 19 amps. I can go to 20A constant with that motor and not hurt it.

Ed

cbatters

With a higher KV rating, I know you could get the same amp draw from a 8" prop but my understanding is that this would provide a higher pitch speed but not as much thrust.



Clint

Sparky Paul

.
The motor/gearbox (if any) and power determine the prop size.
With 400 outrunners, I use 9x4.5s driven directly.
With geared Speed 600s, I use 13x5s.
The Easy Glider uses a 9" prop.

mred

It depends on the kind of flying you want to do. If you are running a high KV motor on a sport plane and intend to fly it kind of fast, then a higher KV motor is called for and more pitch with a smaller prop. If a speed plane, then a higher still KV rating is nice, since you can pull a lot of pitch on a small prop. For gliders, you are looking at a steep climb and you need a tractor to pull something up hill all the time and you need a low gear. Lower KV motors and lower pitch for a glider is what you are after. You want to pull it up hill in a steep climb and not real fast like in a speed model where you want speed. Gliders are not made for speed and some of them will start a wing flutter or come apart if flown to fast. Even in a steep climb, wing flutter can happen if the airspeed is allowed to get to high. Climb speed is what you are after and that means a fair speed in the climb, but not real fast. You sort of have to look at what you are trying to accomplish with each plane. Gliders are meant to fly slow in climb and level flight. (I'm not talking about hotliners here) Get them going to fast and bad things can happen. A big prop with a low pitch is good for a glider because it pulls hard in a climb, but doesn,t get very high in airspeed. The more prop diameter you can put on the motor the better, but not a lot of pitch. 6 inches of pitch is good for pulling, but some of them will pull an 8 inch pitch. They are normally lower turning motors doing that though, not high KV motors. A 14X8 would be a good prop in an 800KV motor, but a 12X8 on a 1300KV motor would be to fast. Look at what you are trying to accomplish when putting a prop on your model and that will decide the diameter and pitch you need.


Ed

rubberducky

hello Clint,
you wrote:
I have seen a lot of posts where people say you need to run a 10 or 11" propellor on a 2M glider. Are you losing a lot in terms of efficiency by spinning a small propellor?
---------

Yes ... why not ... i will try it also with a 10" prop
I take a 25A ESC ... many pilots take only 18A ESC ...
then (may be) the 10" or 11" prop hurts the ESC ...or it will shut off

cbatters

I believe 10 or 11" prop with lower pitch will draw same current as 8" prop with high pitch. Issue is not power in, rather the efficiency and thrust generated.

mred

I don't pay to much attention to the power in, I just prop it for the max constant amps and the biggest diameter prop I can get away with. The more prop you can turn, the more more thrust you will get out of it. I also like to keep my pitch low, at around 4 or 6 on the pitch. I also use a 30A ESC on mine. I never go with an ESC that is close to the rated max on it so I have some head room to play with. It's better to go with a bigger ESC and have it run cooler then to push a smaller one to it's max and have more heat generated. Heat is wasted power and the more you can git rid of the better off you will be. The bigger diameter prop you can turn the better also.

Ed

Kite-lover

Hi, I'm new to this forum.
I saw something about the KD A22/20L here. I will use this motor on a skratch-build Skybolt semi-scale biplane with 1meter span, and a weight of 1 kg (all balsa). I use a 3cell 2200 Mah LiPo and it spinns a 10/5 electro prop. Maybe the maiden flight will be this weekend. My question is: will this motor with a 12/6 Aeronaut folder prop lift a glider of 2,8 m spann with success?
I got a glider, Alfa (Multiplex) with a glass-fiber fuselage that has not flown yet (I live in the flatlands, and don't like a hi-start). I hope for a gentle climb-out (20°).
Kind regards,
Johan

mred

The KD A20 22L is a great little motor, but I think you may be pushing it a little to hard with a 12X6 prop. I have used an 11X6 folding prop on a 2M glider and it runs around 23A with that prop. The motor is rated for 20A constant and 25 A for 60 seconds, so I think you may need to prop down a little, unless you are going to be running at part throttle. Best prop for constant WOT is a 10X6. If your going for 3D, then maybe something like a 10X4.5 of something around there, but check it out first with a watt meter. Running the motor at 25A or so with a 12X6 will burn it up fast. It puts out around 200W and is a great motor for a 2M glider and proped down a little it works great for other planes too. I have used it in a Super Sportster and a small Katana and it flies them very nicely, but watch your amps. You can't go over 20 amps constant. I haven't tried a 12X6 prop on it because the 11X6 runs it at 23 amps, but I am using it in a glider and the motor is not running long. If you want to run a 12X6 prop, I think you will need a different motor. Good luck and have fun.

Ed

Kite-lover

@ Mred,
Thanks for explaining. Can you recommend another engine, in the cheap range for the 2.8 meter glider? Maybee with the same accu? and the same ESC (of 30 Amps)?
Kind regards,
Johan

mred

Hobby City has a lot of motors that will pull a 2.8M glider around. I'm not sure about the 30 amps, but if you are looking for a different motor for the glider, you can start there. The KD will fly a 2.8M glider, but it won't climb all that fast. You may try something like this;

http://www.hobbycity.com/hobbycity/s...utrunner_900Kv

or this one;

http://www.hobbycity.com/hobbycity/s...s_35-48_900Kv_

You can look around Hobby City and find all kinds of motors for your glider. Most of them are under $35.00 and they can pull 30 amps all day without burning up and swing a 13" or 14" prop. Either one of these should pull a 2.8M glider with a good climb.

Ed

Andy in Calgary

Much has been written on this and other conversions but I decided to try it out on an old ARTF Gentle Lady as one of my winter projects.

My build used the following components from Hobby City, I did some research on what I neded but mainly use this vendor due to low cost and good quality product.

Motor KD A22-20L - (only 28mm wide so fits the small nose)
Turnegy 25 Amp BESC - (but bursts to 35A so wont burn out)
Zippy 2100 mah 30-40 C Lipo - (over kill, will use my 20C packs next flights)

It cost less than $80 all in for the launch system and I have another model that doesnt need the high start. The all up weight with the battery, ready to fly, is 2lbs 4oz (36oz) and coupled with a 10x8 folder, on the bench tests it peaked at 271W of power so I thought that would be enough to get her flying.

So its been a bit cold up here since November so no stick time , but this weekend a few of us in the club went out to the field as it had warmed up above freezing and I maidened the bird.

WOW is all I can say, the bench power test should have given it away. This set up is like a Gentle Lady hotliner , it is way over powered and I had to have 2/3 down in to climb out at a sensible 70 degrees on full power. It goes vertical but it's very hard to fly it like that so a lower climb angle is needed. Only flew it the once but the maden flight was 1 hour, up, down, up down etc. a 10 - 15 second burst is all that is required to hit 500 -600 feet each time, Im estmating 20+ climbs.

And the GL is a real floater, even in the cold winter air (no thermals) that sat over our snow sovered field, she flew just about perfectly. I think she'll be my LRM endurance competition model.

This model comes in at 120W per pound, and really 70 - 90 would be more than enough but in having more power than I need to use I was really pleased with the set up above and it was a different flying experience getting up in 15 seconds ratherthan the typical 30 -40 second on other models.

I have a couple of 2M Spirits and might try convering one of those also as I have 2 more motors the same. But first I have a kit of the Bird on Time thats up for conversion over the rest of the winter, Electric, spoilers and possibly Ailerons, I have a 450W combo fort that, a bit less drastic but not a lot even though Im looking to build her a bit heavier at around 4 lbs given the wing area.

mred

Hi Andy

I use that KD motor a lot and I think you may be running it a little hard. Try proping down to a 10X6 and I think your motor will like you better. I use an 11X6 on mine and pull 23 amps and that is a little hard on it too, so I went to a 10X6 and now get 20 amps. That's the top constant running amps for this motor. It will go to 25 amps for 60 seconds, but I think that is kind of pushing it a little. I am using mine in a 2M glider also and it flies it great. It is a great little motor and I love them. I have 6 of them now and use them in all kinds of planes including 2M gliders.

Sounds like you are having fun with it though. To bad it's so cold up there. We had around 75 here today and was nice flying weather. The next two days we get rain, so I guess it's building time again. You have a great combination there with that motor and glider though. I am looking to get something like it or the Sig Riser. No tsure yet. Have fun with your GL and hope you get better flying weather real soon.

Ed

Andy in Calgary

Hi Ed thanks for the note, I'll try a 10x6 next time out.

The main plan with this one was to have another plane I could fit in the back of the truck, all built and that I could get out and get up quickly if I had a spare hour or so over winter.

It actually surpassed all expectations in that it only took a 15 second burst to get to altitude, and then floated like a ballon once it was up. perfect balance and trim first time out. What I found was a simple 30 -40 second climb at say 30 - 40 degrees was achieved ad 1/2 throttle, but it was fun shooting it up like it was on the winch. (note to self- dont snap the wings).

but the set up for the money out perfromed all expectations, as usual with HC, due to the postage costs I usually add to the orders to get as close to the 0..5 KG or 1 KG postage limit, this usuall means an extra motor or 2, an ESC or a new battery. Even paying with CDN $ its worth it.

But yes Im more than happy with the GL, Im a convert to electric sailplanes now, this is the second. Im sure I'll have 4 or 5 in the cupboard by summer.

Andy

mred

I have 4 right now that are electric and 3 2M and 1 that is 2.5M and I love all of them. It's so easy to launch an electric without worrying about hi-starts and winches. I don't think I will go back to the old ways any time soon. I am getting a new 125" next week and will more then likely get another one later. I love gliders and until I find a place close by that I can set up a hi-start, I'll be using electric. I haven't made up my mind yet at to a Sig Riser or a Bird of Time, but I'll more then likely get one of them pretty soon. That should hold me for awhile and give me plenty to fly.

Don't get me wrong on my last statement, you can run your motor at 24.5 amps if you want to, but I just think it is a little hard on the motor. I like to run mine close to the constant amp rating, not the burst rating. Like I said, I ran an 11X6 for awhile, but went to a 10X6 to cut down on the amp draw and hopefully make the motor last longer. I was pulling 23 amps with the 11X6 and didn't see much of a difference in climb between the two props, so I decided to run the smaller one and give my motor a break.

Have fun with your GL, it's a great flying glider and the first one I ever got. After that I went to an Oly II and loved both of them. That was a long time ago though and we didn't have electric motors for them then. Now it's so much easier to fly one without all the problems of setting up. Enjoy.

Ed

cbatters

Any suggestions on brand and source for a 10 x 6 folding prop for the KD A22-20L motor. (I have an old 2M EP glider with a 550 can motor that needs a power boost.)

Any pics of the A22-20L mounted in the fuse would also be appreciated.



Clint