RCHeliJim
09-22-2005, 12:23 AM
September 2005
The Stinger 50 is a relatively new heli on the scene. This heli is imported in the US by Gohbee Aviation. The Gohbee Stinger line of helis is meant to be a low-cost alternative to the current helicopter offerings. Let me start this off by saying that David at Gohbee has been a great help and that the customer service skills he displays are refreshing. He answered every question and offered help every time I needed it.
http://www.helifreak.com/album_mod/upload/e359dc4ad1cebdea4a7cf998de0e6ce9.jpg
The Gohbee comes to you very well packaged in a nice big box. It is currently only available as an ARF (Almost Ready To Fly), which disappointed a "builder" like me, but I will touch on that subject later on.
The Stinger 50 heli is what is called in the industry a "clone", specifically of the Raptor 50. But, the heli does have enough of its own unique parts and ideas to call it a different machine. Lets start with the build.
http://www.helifreak.com/album_mod/upload/f0931a63e5efd5692986f710fe1f0e76.jpg
http://www.helifreak.com/album_mod/upload/e4100ba83148c88ea113468cb327cd21.jpg
The first thing I did with the kit after identifying all the components and reading the manual once through (I find it a good idea to read a whole build manual at least once before beginning a build) was begin a complete teardown of the bird. I decided that since I am reviewing this heli that it would only be fair to begin from scratch, as someone may need to after a crash. I found out during the teardown that this heli is built with care from the factory. EVERY screw that needed loctite had it and every bearing in metal surfaces was glued in as well. My advice to anyone buying a Stinger is to just set it up as the ARF and fly. The factory had every screw and bolt tightened and installed correctly on mine, so it is a pretty safe bet that most kits will be that way, just a good check of the main components should suffice.
http://www.helifreak.com/album_mod/upload/a1c6c643c67db854cad3f8d5f09f795a.jpg
http://www.helifreak.com/album_mod/upload/c3c81b6f598e05ce93343292d1e7cf29.jpg
But, since I did a complete teardown, let us begin with a build from scratch. Once the machine was apart I opened the manual and went to the first full-build page. The Gohbee people have made a great manual with this bird, with separate sections for building the ARF and complete part diagrams. If you have built a Raptor 50 before than 80% of the build will be very familiar to you. Both helis share basically common parts from below the swashplate and down. Let me mention here that the price of a Stinger 50 is about $150 cheaper than a Raptor 50 ? a substantial amount. Some of that savings is "earned" in the build. Please note that your kit and experience may differ greatly from mine, but I hope that some of the fixes that worked for me may also work for you.
http://www.helifreak.com/album_mod/upload/4d38f4a9ab1000becc028b233aeb445d.jpg
http://www.helifreak.com/album_mod/upload/42d9350cad202a46679cfb5fae167b10.jpg
The first section you build on the Stinger is the head assembly, which is also the place where the Stinger differs completely from the Raptor. The head is a unique design, utilizing familiar designs and some of its own. The hub and headblock are very similar to that of the Hirobo Sceadu, as is the swashplate. The flybar control is setup in a different manner than most helis in that the mixing arms ride on the actual flybar instead of a carrier, also the mixing arms are found on the outside of the flybar cage instead of the usual enclosed setup.
The head did pose a few problems for me during the build. Firstly, it was necessary to add a washer inside the center hub to tighten up the flybar seesaw as mine had too much play in it. I also find that the flybar cage is too thin and I was able to twist it out of square, rather or not this can happen with our flight loads I do not know. Two nice things that are stock on the Stinger head setup are a 4mm "Jesus" bolt and adjustable phase timing. The bigger head bolt adds a bunch of strength and security to that area of the heli. I also found that the stock dampeners required a couple more shims in order to feel tight enough for me. I was going to install and use the new 3D dampeners Gohbee has released, but mine had technical difficulties that I couldn't take care of before this review. With shims installed the head tightens up nicely. Also note that the Stinger?s control links are VERY tight on install. I would recommend using a link sizer to get them to the right size, as I did not have one available to me I used the "pliers squeeze" method. It took an uncomfortable amount of squeezing to get the links to fit, but I only broke 2 links in my learning curve. This is where a sizing tool will help greatly.
http://www.helifreak.com/album_mod/upload/3a42fc4e275031000353c2b69a4956fc.jpg
http://www.helifreak.com/album_mod/upload/75b09af48a93bf2a539d580159c95a0c.jpg
http://www.helifreak.com/album_mod/upload/70372f6beea7ae6d66cf9f48978f8c67.jpg
After this point MUCH of the build is like the Raptor 50. The fuel tank has a plate taped to the bottom which then screws into the frames, this is a nice add-on to the heli and it really secures the fuel tank in. As I was installing the screws that hold the frames together, I broke two of the frame posts that join the halves. I find the plastic used in these posts to be a little too brittle for this "gorilla". I replaced the frame posts with Raptor ones and moved on to the next step. The rest of the frame went together well and seems to be a strong base for the heli.
http://www.helifreak.com/album_mod/upload/a1fc54f5766b0433aa3cadaff62a0844.jpg
http://www.helifreak.com/album_mod/upload/f9e5412c930637f4391f35b36f9f9700.jpg
This area gave me HUGE problems for a while. You will see that the fix for it turned out to be simple and would have saved me a bunch of time had my brain worked quicker, but what do you expect from a bonehead! The collective arm on the Stinger is an all-metal unit, great looking and strong. Everything installed on it nicely and the bearings are a nice fit in the arm halves. The problem occurred on my heli where the arm pivots on the main frames. The bolt holes in the frame halves for the collective arm on my model don't line up perfectly, one of them is slightly forward of the other. When I installed the pitch arm, I noticed the back end "twisted" to one side, causing the elevator arm to rub and bind on the mainshaft. At first, I thought the screw holding the elevator arm to the collective plate was too long, but soon noticed the misaligned arm. My multiple attempts at bending, reseating, and otherwise mangling the arm were unsuccessful. Here is what worked for me and gave me a slop and bind free collective arm: 1) Attach both arm halves, loosening the servo plate screws all around the arm halves. 2) Press the front of the arm (by the collective control ball) until the arm halves are straight and parallel to the frame. 3) While holding this position, tighten all the servo arm screws nice and tight (don't forget the threadlock). When you let go of the arm, it should stay locked in that position and move freely up and down. I realize that this may be a problem only found on my model, but if anyone else runs into the same problem, this should help them out.
http://www.helifreak.com/album_mod/upload/841d82aed116c5a5e963c2fca6327b43.jpg
http://www.helifreak.com/album_mod/upload/c081db244ea3b58ce78cbada6fe232d0.jpg
http://www.helifreak.com/album_mod/upload/5d234467a9dd12764ccce8eb13eb4cd7.jpg
From here on out the build goes better for me. The clutch system is designed much like the Sceadu in that the start shaft is part of the clutch. My clutch lined up real well once I tightened the six (yes, I said six) motor mount screws. I liked that the Gohbee people utilized the bottom mounting holes in the frames and added 2 more screws to the motor mount. It helped line things up real well.
http://www.helifreak.com/album_mod/upload/910b131acbe7b857dbde3dbbffd7a6ad.jpg
In the tail assembly, I replaced the stock tail hub with the new SUS Raptor hub. The stock Stinger hub is also upgraded, but when I removed it during disassembly the threads got damaged in one of the setscrew holes, so I used the new Thunder Tiger part. I also sanded the blade grips a bit to give them a tighter fit on the bearings. I replaced the stock plastic tail blades with some Mavrikk carbon ones I had in my parts box.
http://www.helifreak.com/album_mod/upload/f2ad61ce5f88900e202ec622abbfd863.jpg
http://www.helifreak.com/album_mod/upload/6fc0ac405aa991f4045c17efc7857adb.jpg
Now the heli is ready for the electronics. Everything in this area install just like on a Raptor. One thing to note is that the Gohbee manual has the recommended link lengths near the back of the manual. These settings will give you a good starting point. Also, the Gohbee comes with plastic servo plates that I was able to break on almost every servo (again, I am a gorilla). Replace these with some metal plates if you have them.
http://www.helifreak.com/album_mod/upload/425ef7b64d1019a3854c66fd4aab5821.jpg
http://www.helifreak.com/album_mod/upload/4762e3347883eee9c283eee72895a3d2.jpg
Here is a list of the electronics and motor setup I used in this bird:
Engine: OS 50 Hyper
Muffler: Hatori SB-50 Krause Special
Servos: Futaba 9252s on controls and a JR 811 on throttle
Gyro: Futaba 401 and 9254 combo
Receiver: JR R770 PCM
Battery: Duralite 2800
http://www.helifreak.com/album_mod/upload/c7f4f7c57a81c4067ee5ae22b51aa2dc.jpg
http://www.helifreak.com/album_mod/upload/58d60009600e158da44697124ac6f023.jpg
http://www.helifreak.com/album_mod/upload/8b5bb4d81cf7e9cf757e9f27a02d9301.jpg
Well here she is all ready to go. I am sure you have notice the Raptor canopy installed on the bird. My stock Gohbee canopy had a mishap in the basement and I did not get a replacement in time for the review. Now lets go on to the flight review.
FLIGHT
I took the heli fresh from the building table to the IRCHA Southwest funfly in Salt Lake City, Utah. This was a short trip for me as I live 30 minutes south of SLC. Friday morning I took her out to the flight line for her first run. The motor I installed had already been broken in. I turned on my trusty JR 9303 and then switched on the heli. Everything worked right and the controls all went the right way so we fired up the motor.
The clutch grabbed instantly, I could not set the idle low enough to make the clutch disengage completely. I imagine with some time the clutch on the bird will not be as tight. Holding the headblock tight I walked it to the flight area and stepped back so the blades could spin. The first thing I noticed was a gear noise. I had been warned that the main gears on the Stinger are usually a little out of round and that some break in is required, so I throttled up. From this point on I chased a number of headspeed issues and other engine related issues that I couldn't track down. We also had a mean head wobble that went away with a new set of dampeners and 2 more washers on the spindle.
Later in the weekend I had a very experienced pilot in the club, John Morgan, come help me out with the heli. He was able to tame the headspeed somewhat using the radio curves (I am still tracking down that issue) and take her up in the air. He did an auto with it and some hovering and forward flight. We both noticed that the heli needed more work to fly as smooth as expected. I ran out of time to track down the issues that made the headspeed crazy and control a little sloppy. I did notice that the washout and elevator arms have a lot more slop in them than I am used to and this may contribute to the problems I had. I am sure that with some more work and maybe some replacement parts that the head will fly smooth and true. I ran out of time to do any more flight testing and unfortunately need to sell this Stinger in order to get the funds I need to fix my main bird after it had a night flying tail failure.
Also, I was able to put the new 3D dampeners and metal headblock in while flight testing, my headblock and dampener bushings weren't machined quite right; so David offered to machine a custom set of bushings to fit my headblock. Now that's service!!
My flight testing is far from substantial, but I feel that some break in on the gears and links is required to make this heli fly smoother. The head felt very responsive with stick inputs and I think once setup and broke-in that it will 3D great. I also think that with a kit at this great price that you may get a higher percentage of misaligned and defective parts in each kit, but the service at Gohbee is outstanding and I have no doubts that they will take care of any problems a customer finds.
http://www.helifreak.com/album_mod/upload/de979362ddbc2750231428882229942d.jpg
For the price, it is hard to beat the Stinger for value. Crash parts and spares are very well priced and the company service is outstanding. A pilot may need to put more time into setup and small fixes than on the more expensive helis in order to get the performance desired, but it can be done and has been done by a number of Gohbee pilots. Many have had no problems with this heli right out of the box, and some have had numerous like I did. Since the machine is imported it is real hard for Gohbee to make sure each kit is perfect as they leave the warehouse, but when there is a problem, David and his staff is there to help you out. This heli definitely has a place in the hobby and I am sure we will see more and more of them in the near future.
Please see my gallery for more Stinger pics and also look for my review on the Hatori SB-50 Pipe. Thanks, Jim
The Stinger 50 is a relatively new heli on the scene. This heli is imported in the US by Gohbee Aviation. The Gohbee Stinger line of helis is meant to be a low-cost alternative to the current helicopter offerings. Let me start this off by saying that David at Gohbee has been a great help and that the customer service skills he displays are refreshing. He answered every question and offered help every time I needed it.
http://www.helifreak.com/album_mod/upload/e359dc4ad1cebdea4a7cf998de0e6ce9.jpg
The Gohbee comes to you very well packaged in a nice big box. It is currently only available as an ARF (Almost Ready To Fly), which disappointed a "builder" like me, but I will touch on that subject later on.
The Stinger 50 heli is what is called in the industry a "clone", specifically of the Raptor 50. But, the heli does have enough of its own unique parts and ideas to call it a different machine. Lets start with the build.
http://www.helifreak.com/album_mod/upload/f0931a63e5efd5692986f710fe1f0e76.jpg
http://www.helifreak.com/album_mod/upload/e4100ba83148c88ea113468cb327cd21.jpg
The first thing I did with the kit after identifying all the components and reading the manual once through (I find it a good idea to read a whole build manual at least once before beginning a build) was begin a complete teardown of the bird. I decided that since I am reviewing this heli that it would only be fair to begin from scratch, as someone may need to after a crash. I found out during the teardown that this heli is built with care from the factory. EVERY screw that needed loctite had it and every bearing in metal surfaces was glued in as well. My advice to anyone buying a Stinger is to just set it up as the ARF and fly. The factory had every screw and bolt tightened and installed correctly on mine, so it is a pretty safe bet that most kits will be that way, just a good check of the main components should suffice.
http://www.helifreak.com/album_mod/upload/a1c6c643c67db854cad3f8d5f09f795a.jpg
http://www.helifreak.com/album_mod/upload/c3c81b6f598e05ce93343292d1e7cf29.jpg
But, since I did a complete teardown, let us begin with a build from scratch. Once the machine was apart I opened the manual and went to the first full-build page. The Gohbee people have made a great manual with this bird, with separate sections for building the ARF and complete part diagrams. If you have built a Raptor 50 before than 80% of the build will be very familiar to you. Both helis share basically common parts from below the swashplate and down. Let me mention here that the price of a Stinger 50 is about $150 cheaper than a Raptor 50 ? a substantial amount. Some of that savings is "earned" in the build. Please note that your kit and experience may differ greatly from mine, but I hope that some of the fixes that worked for me may also work for you.
http://www.helifreak.com/album_mod/upload/4d38f4a9ab1000becc028b233aeb445d.jpg
http://www.helifreak.com/album_mod/upload/42d9350cad202a46679cfb5fae167b10.jpg
The first section you build on the Stinger is the head assembly, which is also the place where the Stinger differs completely from the Raptor. The head is a unique design, utilizing familiar designs and some of its own. The hub and headblock are very similar to that of the Hirobo Sceadu, as is the swashplate. The flybar control is setup in a different manner than most helis in that the mixing arms ride on the actual flybar instead of a carrier, also the mixing arms are found on the outside of the flybar cage instead of the usual enclosed setup.
The head did pose a few problems for me during the build. Firstly, it was necessary to add a washer inside the center hub to tighten up the flybar seesaw as mine had too much play in it. I also find that the flybar cage is too thin and I was able to twist it out of square, rather or not this can happen with our flight loads I do not know. Two nice things that are stock on the Stinger head setup are a 4mm "Jesus" bolt and adjustable phase timing. The bigger head bolt adds a bunch of strength and security to that area of the heli. I also found that the stock dampeners required a couple more shims in order to feel tight enough for me. I was going to install and use the new 3D dampeners Gohbee has released, but mine had technical difficulties that I couldn't take care of before this review. With shims installed the head tightens up nicely. Also note that the Stinger?s control links are VERY tight on install. I would recommend using a link sizer to get them to the right size, as I did not have one available to me I used the "pliers squeeze" method. It took an uncomfortable amount of squeezing to get the links to fit, but I only broke 2 links in my learning curve. This is where a sizing tool will help greatly.
http://www.helifreak.com/album_mod/upload/3a42fc4e275031000353c2b69a4956fc.jpg
http://www.helifreak.com/album_mod/upload/75b09af48a93bf2a539d580159c95a0c.jpg
http://www.helifreak.com/album_mod/upload/70372f6beea7ae6d66cf9f48978f8c67.jpg
After this point MUCH of the build is like the Raptor 50. The fuel tank has a plate taped to the bottom which then screws into the frames, this is a nice add-on to the heli and it really secures the fuel tank in. As I was installing the screws that hold the frames together, I broke two of the frame posts that join the halves. I find the plastic used in these posts to be a little too brittle for this "gorilla". I replaced the frame posts with Raptor ones and moved on to the next step. The rest of the frame went together well and seems to be a strong base for the heli.
http://www.helifreak.com/album_mod/upload/a1fc54f5766b0433aa3cadaff62a0844.jpg
http://www.helifreak.com/album_mod/upload/f9e5412c930637f4391f35b36f9f9700.jpg
This area gave me HUGE problems for a while. You will see that the fix for it turned out to be simple and would have saved me a bunch of time had my brain worked quicker, but what do you expect from a bonehead! The collective arm on the Stinger is an all-metal unit, great looking and strong. Everything installed on it nicely and the bearings are a nice fit in the arm halves. The problem occurred on my heli where the arm pivots on the main frames. The bolt holes in the frame halves for the collective arm on my model don't line up perfectly, one of them is slightly forward of the other. When I installed the pitch arm, I noticed the back end "twisted" to one side, causing the elevator arm to rub and bind on the mainshaft. At first, I thought the screw holding the elevator arm to the collective plate was too long, but soon noticed the misaligned arm. My multiple attempts at bending, reseating, and otherwise mangling the arm were unsuccessful. Here is what worked for me and gave me a slop and bind free collective arm: 1) Attach both arm halves, loosening the servo plate screws all around the arm halves. 2) Press the front of the arm (by the collective control ball) until the arm halves are straight and parallel to the frame. 3) While holding this position, tighten all the servo arm screws nice and tight (don't forget the threadlock). When you let go of the arm, it should stay locked in that position and move freely up and down. I realize that this may be a problem only found on my model, but if anyone else runs into the same problem, this should help them out.
http://www.helifreak.com/album_mod/upload/841d82aed116c5a5e963c2fca6327b43.jpg
http://www.helifreak.com/album_mod/upload/c081db244ea3b58ce78cbada6fe232d0.jpg
http://www.helifreak.com/album_mod/upload/5d234467a9dd12764ccce8eb13eb4cd7.jpg
From here on out the build goes better for me. The clutch system is designed much like the Sceadu in that the start shaft is part of the clutch. My clutch lined up real well once I tightened the six (yes, I said six) motor mount screws. I liked that the Gohbee people utilized the bottom mounting holes in the frames and added 2 more screws to the motor mount. It helped line things up real well.
http://www.helifreak.com/album_mod/upload/910b131acbe7b857dbde3dbbffd7a6ad.jpg
In the tail assembly, I replaced the stock tail hub with the new SUS Raptor hub. The stock Stinger hub is also upgraded, but when I removed it during disassembly the threads got damaged in one of the setscrew holes, so I used the new Thunder Tiger part. I also sanded the blade grips a bit to give them a tighter fit on the bearings. I replaced the stock plastic tail blades with some Mavrikk carbon ones I had in my parts box.
http://www.helifreak.com/album_mod/upload/f2ad61ce5f88900e202ec622abbfd863.jpg
http://www.helifreak.com/album_mod/upload/6fc0ac405aa991f4045c17efc7857adb.jpg
Now the heli is ready for the electronics. Everything in this area install just like on a Raptor. One thing to note is that the Gohbee manual has the recommended link lengths near the back of the manual. These settings will give you a good starting point. Also, the Gohbee comes with plastic servo plates that I was able to break on almost every servo (again, I am a gorilla). Replace these with some metal plates if you have them.
http://www.helifreak.com/album_mod/upload/425ef7b64d1019a3854c66fd4aab5821.jpg
http://www.helifreak.com/album_mod/upload/4762e3347883eee9c283eee72895a3d2.jpg
Here is a list of the electronics and motor setup I used in this bird:
Engine: OS 50 Hyper
Muffler: Hatori SB-50 Krause Special
Servos: Futaba 9252s on controls and a JR 811 on throttle
Gyro: Futaba 401 and 9254 combo
Receiver: JR R770 PCM
Battery: Duralite 2800
http://www.helifreak.com/album_mod/upload/c7f4f7c57a81c4067ee5ae22b51aa2dc.jpg
http://www.helifreak.com/album_mod/upload/58d60009600e158da44697124ac6f023.jpg
http://www.helifreak.com/album_mod/upload/8b5bb4d81cf7e9cf757e9f27a02d9301.jpg
Well here she is all ready to go. I am sure you have notice the Raptor canopy installed on the bird. My stock Gohbee canopy had a mishap in the basement and I did not get a replacement in time for the review. Now lets go on to the flight review.
FLIGHT
I took the heli fresh from the building table to the IRCHA Southwest funfly in Salt Lake City, Utah. This was a short trip for me as I live 30 minutes south of SLC. Friday morning I took her out to the flight line for her first run. The motor I installed had already been broken in. I turned on my trusty JR 9303 and then switched on the heli. Everything worked right and the controls all went the right way so we fired up the motor.
The clutch grabbed instantly, I could not set the idle low enough to make the clutch disengage completely. I imagine with some time the clutch on the bird will not be as tight. Holding the headblock tight I walked it to the flight area and stepped back so the blades could spin. The first thing I noticed was a gear noise. I had been warned that the main gears on the Stinger are usually a little out of round and that some break in is required, so I throttled up. From this point on I chased a number of headspeed issues and other engine related issues that I couldn't track down. We also had a mean head wobble that went away with a new set of dampeners and 2 more washers on the spindle.
Later in the weekend I had a very experienced pilot in the club, John Morgan, come help me out with the heli. He was able to tame the headspeed somewhat using the radio curves (I am still tracking down that issue) and take her up in the air. He did an auto with it and some hovering and forward flight. We both noticed that the heli needed more work to fly as smooth as expected. I ran out of time to track down the issues that made the headspeed crazy and control a little sloppy. I did notice that the washout and elevator arms have a lot more slop in them than I am used to and this may contribute to the problems I had. I am sure that with some more work and maybe some replacement parts that the head will fly smooth and true. I ran out of time to do any more flight testing and unfortunately need to sell this Stinger in order to get the funds I need to fix my main bird after it had a night flying tail failure.
Also, I was able to put the new 3D dampeners and metal headblock in while flight testing, my headblock and dampener bushings weren't machined quite right; so David offered to machine a custom set of bushings to fit my headblock. Now that's service!!
My flight testing is far from substantial, but I feel that some break in on the gears and links is required to make this heli fly smoother. The head felt very responsive with stick inputs and I think once setup and broke-in that it will 3D great. I also think that with a kit at this great price that you may get a higher percentage of misaligned and defective parts in each kit, but the service at Gohbee is outstanding and I have no doubts that they will take care of any problems a customer finds.
http://www.helifreak.com/album_mod/upload/de979362ddbc2750231428882229942d.jpg
For the price, it is hard to beat the Stinger for value. Crash parts and spares are very well priced and the company service is outstanding. A pilot may need to put more time into setup and small fixes than on the more expensive helis in order to get the performance desired, but it can be done and has been done by a number of Gohbee pilots. Many have had no problems with this heli right out of the box, and some have had numerous like I did. Since the machine is imported it is real hard for Gohbee to make sure each kit is perfect as they leave the warehouse, but when there is a problem, David and his staff is there to help you out. This heli definitely has a place in the hobby and I am sure we will see more and more of them in the near future.
Please see my gallery for more Stinger pics and also look for my review on the Hatori SB-50 Pipe. Thanks, Jim