Bigtone

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The L-39 is the most accessible jet fighter trainer in the world. Hundreds are owned and operated by private pilots, while more than 2,500 are in military service worldwide. Without the cost or complexity of many ducted fan jets, the L-39 is capable of blistering speed without sacrificing flight time. It performs well throughout the flight envelope, on power and off. The HyperFlow ducted fan and Ammo brushless motor combination produces impressive thrust and speed. When you can’t be out performing rocketing climbs and high-speed passes, admire your L-39 on this included display stand. Main structures — fuselage, wing, tail surfaces — are molded, finished, and ready for fast assembly. The L-39’s smooth AeroCell™ surface comes already finished with a military-style camouflage trim. Decals are also factory applied and detachable display magnetic armament is included. Magnet-secured hatch covers make the L-39's battery and ducted fan compartments easily accessible. Plenty of room is available for installing a wide range of battery sizes.

SPECIFICATIONS
Stock Number: GPMA1869
Wingspan: 25 in (635 mm)
Wing Area: 141 in² (9.1 dm²)
Weight: 17.5-18.5 oz (500-520 g)
Wing Loading: 17.9-18.9 oz/ft² (55-58 g/dm²)
Length: 31 in (780 mm)
Includes: HyperFlow Ducted Fan Unit with 20-40-3500 Ammo In-Runner Brushless Motor
Requires: 3-channel radio w/3 micro servos

[link=http://video1.hobbico.com/gallery/gpm/gpma1869-large.mpg]

Click for Quick Time Video!

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3D-Kid

This plane looks pretty cool. I was pricing these earlier and on tower is says $99.99, not too bad for including an Ammo brushless motor. Video seems like it really pulls too.
Any thoughts????

surjer

anyone? I did a search and found 1 other thread that matched "Great Planes L-39". Someone mentioned issues with one of the servo's but has anyone else had/have this plane? Very curious..

Mr. Mugen

I would be willing to bet it is a lot like the synapse......not as fast in person. []

R/C FLYR

My Feedback: (1)

I have heard with the 3500 ammo motor and their fan setup it is supposed to do around 86 m.p.h. sounds cool!! i saw a chart on it showing thrust values, power to weight...etc if that turns out to be true WOW R/C FLYR

surjer

Man - I think imma get one.. 99 bucks you cant go wrong! lol Only thing that scares me is its made out of EPS... Isnt that like styrofoam cooler foam? Like one crash and it explodes? Will be my 2nd plane! Bye bye super cub hello EDF! lol (I bet I will be welcoming my SuperCub back ehh>?)

gundamnitpete

more like 50 mph, slower than a stryker. you need a much higher KV motor in that small fan to get 80 MPH

R/C FLYR

My Feedback: (1)

Not according to their chart, ,I would tend to believe that their research and development team knows what they are talking about, but only one way to find out, and that is to get one and see what it does R/C FLYR

stoneenforcer

My Feedback: (23)

86 MPH !!! hahahaha thats too funny. That stock setup doesn't get out of first gear. Heck, even if you did throw in some serious KV, I highly doubt the wings will stay on. Not to mention the need of a decent batt. with limited space. Not to sound negative, it looks great on the video if that type of performance will satisfy you, but from all the EDF's they have mfg.'d and I've built/flown, I've come to not expect much from "them". Myself as well as club members have come to find FALSE claims to the performance levels posted above. If you believe everything a tech writes, your just a sucker.

gundamnitpete

the chart stats about 14.7 ounces of thrust and an efflux of 126 with that motor.

it's a sales gimmick, if you have bought any of thier ducted fans you would know this, the XPD-8 is a great example. the stock motor has BARELY enough power to get out fo it's own way, and the tip stalls are rediciousl. same with the synapse.

i'm sure it'll fly fine, but as i stated, using my OWN data on the hyperflow fan, i would be suprised to see more than 50 mph striaght and level.

R/C FLYR

My Feedback: (1)

Well it sure does suck then if they have to give you a line of crap just to buy their products it just aint right R/C FLYR[&o]

RCmob

Hello gundamnitpete and R/C Flyer,

I work in the Hobbico R&D department and I can tell you that the thrust and efflux speed number shown here: http://manuals.hobbico.com/gpm/gpmg3...anual-v1_1.pdf are absolutely real. Please keep in mind that the performance detailed, as the Hyperflow manual says in pages 2 and 3, was obtained using the specified motor and with the Hyperflow intake lip and various exhaust cones. That said, each airplane's intake, exhaust and length/shape of the duct will affect the performance of the fan in one way or the other and change the thrust/speed relationship, along with adding some losses due to pressure changes and drag inside the tube. In addition to this you have to account for airframe drag. The numbers published for the fan, then, cannot be directly related to airplane performance, as that would be like saying that a 9x6 APC prop at 10.000 rpm will cause any airplane it is being used in to perform exactly the same way.

On the EDF planes, we have tried several different ways to explain their performance. The XPD-8 will fly straight an level at the advertised speed of 55mph using the stock 370BB brushed motor, and it will climb at about 45-50 degree angle for as long as you want. This has been verified by plenty of people in this and other forums. We verified this data with a speed gun first and then by measuring the Doppler effect before publishing the data. If your plane did not perform as advertised, please send it in and address it directly to me (send PM) as we would like to know why and hopefully use that knowledge to ensure a more satisfactory experience for our customers. Please realize that we are not here to sell you one plane and forget about you. We are here/have been here for the long run and we want you to be happy with our products so you buy more.

On the snapping issues, all I can say is that our testing involves high speed straight down dives with added weight (+10%) with high/rate elevator pulls to a loop (positive and negative) and snaps at the bottom to test for structural integrity, flutter and high speed stalls. No airplane is released until we figure h/r throws that will allow the plane to perform all the maneuvers expected from it through the entire CG range recommended WITHOUT ANY hint of high speed stall. While there are many variables that could affect this (air density, temperature, etc) we chose the heaviest configuration and we add the extra weight to account for as many of those variables as possible. The testing process is long, detailed and extreme so we can find any problems and fix them before the plane is released. What has the most effect on snapping performance is incorrectly set throws, CG or overweight airframes. On a 13 oz airframe, every oz makes a huge difference in performance.

The Synapse uses an AMMO 20-40-3500. This motor will deliver 14 oz of static thrust at 15.7A when using the Hyperflow with its intake lip and the exhaust specified in the instructions. In the plane, performance is slightly lower due to the not-as-optimal intake and exhaust. This is because compromises are always needed when designing airplanes. There is no way around it. That said, the Synapse RxR does 77mph straight and level and about 85MPH after a dive as well as 70 degree climbs for as long as you want. It will do even better with more powerful options available for the ARF. This again, has been verified by plenty of people in this forum and others. If the plane you have is not performing to these numbers, then send it in as we would like to find out why.

The part that is a bit puzzling to us is the problems that people are having with the take off launches. If the plane is setup as recommended (CG, throws, weight, power) the plane is actually extremely easy to launch. I generally go full power, grab it by the nose (3-4 inches in front of the intake) and give it a light, straight toss and the plane goes away perfectly steady without any drama. However, judging by comments on this forum, it just seems like it is a bear to fly. I would like to know why. Are you aware of any videos posted that we could look at? Do you have any personal experiences that you would like to share? We want to see if we can figure out what is not working to guarantee success in the future, not frustrated customers. I am considering making a short video showing the appropriate launching technique.

Please consider sending us your planes if you have had problems with them. Hopefully we can find what is wrong and correct the issue.

Sincerely

RCmob

RCmob

I forgot to mention that the stock RxR L-39 straight-and-level speed is 60mph. After a dive it will do 72mph. The ARF version can be setup with more powerful motors that will make it go much faster.

Thank you

RCmob

matthewxxx99

RCmob I have a question about the servos that come in the Synapse RXR. I have read a lot about the problems with the servos being junk. I am willing to buy the ARF but was wondering about this problem and any help would be appreciated.

RCmob

Hello Mattewxxx99

It is always hard to come up with a ready to fly or RxR product and please everyone. When such product is first devised, we figure out to the best of our abilities who the target market is, what the expected performance is and target price. For a product to be successful it has appeal to the most people, be structurally sound and deliver the expected performance. All of these mean compromises in everything as every component change affects everything else. It also means that we will not please everyone since all of us have different expectations.

With this out of the way, I will tell you that many units of the servos used in the Synapse RxR were tested extensively on different Synapse samples as well as other planes. This was done to find the practical limits of the servo in actual flight. We went through a few different samples to get to the final iteration. The servos were also stress tested at higher speeds and loads than those seen in the Synapse. We feel that the servos included in the Synapse RxR are adequate for the airplane's performance. Sure, they are no Futaba S3153, but they were never intended to be. If they were, the street price of the RxR synapse would be much higher and then we would get complaints for that. Remember that we are trying to please the most people and so a compromise has to be reached. The actual number of complaints received regarding servo performance is less than 1% of RxR product shipped, so we feel that we have not done that bad. It is very easy, however, to throw out and ambiguous term like "junk" based on one's perception and expectations to "make everyone aware about a problem" when unfortunately the 99% who has not had any problem with those servos is not chiming in, saying that they work fine for them. In the end, those who feel that their product under performs, can return it under warranty. They do not need to be upset as we offer and honor a very good warranty.

A different deal is when the servo simply does not function. The complaints received again amount to less than 1% of items shipped. If anybody's airplane has such problem, the plane can be sent in for a replacement under warranty. No questions asked. That is why we offer such warranty. We apologize for any inconvenience caused by this and just like you, we wish that all product always came out perfect. We have extensive testing and QC programs to try to make the product as good as possible. We take pride on our products, but we cannot control everything and sometimes a bad unit might reach a customer.

In addition to what is explained above, I can assure you that when we receive or see reports of unexpected problems, we quickly go back and check samples of products in stock to check if even after testing and QC, we can still find products with problems that need to be addressed. We honestly try hard and learn from our mistakes, if made, to improve subsequent production runs.

Now that all this is explained, maybe the next thing to say is that while the RxR and RTF versions of our planes will perform as advertised and as most people expect (certainly as we expect), the discriminating modeler has the option of purchasing the ARF version of the same product. While we all want the convenience of the RxR versions, the ARF versions allow each one of us to customize the product with the equipment we deem acceptable to ourselves thus eliminating the ready-made decisions made by somebody else (Great Planes development team)

I hope this helps

RCmob

matthewxxx99

RCmob, Thanks forthe information. Like you have said I figured it just did not meet their expectations or they crashed it and blamed it on the servos or motor. I have ordered mine and should have it in the air soon. I have bought the ARF and have decided to put a few upgrades in it. I think that GP stand behind all of their products and I have never had any problems with any of the planes that I have. I imagine that some people rush the setup and that is the problem they are having. I built a bungee launcher and that is the way to go for launching small to medium planes and it will save you from hand launches. I am planning on selling them on ebay including every thing in one package with nothing else to buy. Thank you for the information, Matthew If anyone is interested in contacting me about a BUNGEE LAUNCHER please contact me.

NoFlaps

My Feedback: (131)

keep us posted on this...i'd like to see that bungee in actions also.

matthewxxx99

If you go to youtube.com and type in "great planes synapse" you will see the video of the launch and the bungee that I am using and I also use the same setup that he does. I have used the launcher without one close call getting my planes in the air. I build mine so it is easy to put take apart for travel. If you have any questions just let me know.

surjer

Man this blows - I have bought 2 other EDF's while waiting on this dang plane to get released. NOW its pushed back to Late Jan! I am on the email waiting list but my guess is I will miss out when this thing gets released and will have to wait another 5 months.. What gives? Why do you guys keep pushing back the release date? I mean - I am sure there is a good reason and I wouldnt want it released early if there are problems with it but seriously. Why is it sooo late in getting released?

surjer

Make that late FEB now.... Changed AGAIN! wow... lol

cubnpede82

Hey, my buddy is really into EDF and his twister is pretty darn cool
I like the size and the Electrifly EDF unit seems to be a good fan unit from what I have seen/heard
One guy here is putting a wemotec mini 480 EDF unit in a twister, should really scream on 4cells

This is perfect trunk size and looks like a real plane, and not to many Russian planes were modeled, can't find any WWII parkie type russian planes. Is it out yet? anyone fly it? I'd realy like to know it an 1800 3 cell can fit with an AR6100 Rx.

let me know?

Isaiah [email protected]

spindoctor4140

well I just got my l-39 in and flew it and like a lot of you said it always looks faster in the videos. no way does it even get close to 86 mph. im using the stock setup with a 1320 thunder power lipo and an electrifly ss-25. The plane has a really nice slick profile in the air which makes me not dislike it. It's just the fact that im into speed. it does produce pretty decent thrust and i have no problem hand launching it at all. I want to go to 4s but the motor wont take it. Pretty stable plane in the air and glides probably the best for any jet i've seen or flown under no power. I've flown it inverted, barrel rolled all with perfect pinpoint tracking of the plane. I think with a higher kv motor on 11.1 volts it'll pick up speed fast but knowing me im going to go all out and mod it more than it needs. the fusalage has plenty of room for a wemo fan. ill probably go with a wemo fan, kontronik motor probably 3600 kv and go fourteen volts. It should be gone with that setup. ha but thats probably way overkill but thats how i like it. But overall the plane is fantastic plane for someone getting into edf. forgiving material for crashes. building took me about 4 hours only because i had to wait for my epoxy work to cure but totally simple. I do love the canapy magnets and the motor access hatch magnets. super strong magnets and makes everything easy. I think the plane is definately worth 99 bucks. that super cheap for somethin that includes motor and fan too.

zsparks

My Feedback: (1)

I am working on getting mine finished also. I am two hours into the build right now and only a few more sections of the manual left. VERY easy to put together. Waiting on the glue is the only thing stopping this plane from being done already.

Mr. Mugen

The Synapse uses an AMMO 20-40-3500. This motor will deliver 14 oz of static thrust at 15.7A when using the Hyperflow with its intake lip and the exhaust specified in the instructions. In the plane, performance is slightly lower due to the not-as-optimal intake and exhaust. This is because compromises are always needed when designing airplanes. There is no way around it. That said, the Synapse RxR does 77mph straight and level and about 85MPH after a dive as well as 70 degree climbs for as long as you want. It will do even better with more powerful options available for the ARF. This again, has been verified by plenty of people in this forum and others. If the plane you have is not performing to these numbers, then send it in as we would like to find out why.



Well I bought 2 of these when released and can tell you that 77 is far fetched... 57 is closer. I could sit here all day and tell you why it wont hit 77 but I assume most already know why. I have plenty of exp. with planes that actually fly 77 or higher and this is not a 77mph stock bird....at least the 2 I got weren't. I did all break in per instructions and used the suggested 1320 pack.....no go. Not like described here or shown in video.

Just my .02 and I do not get paid by anyone.
Kevin

RCmob

Dear Mr Mugen.

The stock Synapse has been extensively tested and clocked (by measuring distance/time, with a Stalker speed gun and Waveoscope) to have an average speed of 77mph on a straight, full power run. This was done with the recommended gear while doing passes left to right and right to left.

If you have used the recommended gear and you have a way to verify that the plane does not perform as advertised (time it), please send the plane back. We will test it and if it does not perform, we will replace it. Please send a PM if you want to do so.

As stated earlier, we stand by our product.

Thank you

RCmob