I first learned of JL Products and their Roto Flow gas tanks from reading an RC magazine. Sadly, I do not remember which one. I contacted JL Products, by e-mail. I told them that I thought they had a good thing, and asked when they would be making smaller tanks (for us 40 size fliers). I received an e-mail from Donald Spychalla stating the molds for the 10 and 12 ounce tanks were being manufactured. Donald told me the tanks should be ready in about 8 weeks. I replied with telling him I would love to try one out. Sure enough, 8 weeks later there was a 12 ounce Roto Flow tank delivered to my house.
Now, for a little bit about me. I have been flying for a little over a year, and average 10 days at the field per month (and anywhere from 5-8 hours, per day, depending on time of year). I started with electrics, then moved straight into a Nitro Edge 540. Through some "growing pains" I learned how to take off, fly and land my 40 size Seagull Edge 540. I probably should have gotten a nitro trainer first. I am an AMA member, and fly at a Bob Miller Field in Saucier Ms. (our club web site is mcrcc.net).
A little bit about my plane. As you just read, my plane is the 40 size Seagull Edge 540. It is outfitted with an O.S. .55 and a #8 plug. The motor is turning a 12x4 APC Prop, and the prop is mounted on a aluminum Tru Turn Spinner. Control surfaces are controlled by Spektrum DS821 Servos. The throttle has a standard size Futaba S3004 servo. I'm using a Spektrum AR6210 receiver, in conjunction with a Spektrum DX6I. And the battery is a 6 volt 2000Mah Hydrimax battery hooked up to a 3 wire heavy duty EMS Spektrum compatible switch.
When I first started flying the plane, I was only getting 6 minute flight times. And of course, out of fuel, dead stick landings. I learned that the stock gas tank was only a 7.75 ounce gas tank. So, with the help of a well seasoned club member, the tank was changed to a Du Bro 12 ounce gas tank (which we learned will provide 13.45 minutes of flight, due to a throttle servo arm that fell off at full throttle).
The one thing I was concerned about, was a stuck clunk. I have heard of it happening, and have seen it happen. I personally have never had it happen to me. One of the first thing everyone checks, when they have a crash related to fuel, is was the clunk stuck forward. And I have witnessed that, being a part of the after crash evaluations.
When I saw the Roto Flow gas tank, I thought "if it works, as advertised...and in the event of a crash, you can automatically rule out a stuck clunk".
I took the tank to my local club (and invited 2 other area clubs), for it to be seen and handled, before I installed it my plane. There were 2 concerns.
The first was, would it handle the pressures of a YS Engine? I sent Donald an e-mail asking if it would handle the pressures of a YS Engine. His reply e-mail stated that the wall thickness of the Roto Flow tank is .065 to .110 thousandths thick. His e-mail also said that most other tanks have a wall thickness of .020 to .045 thousandths. Donald did tell me that, although the tank has not been tested on a YS Engine, he has several satisfied customers using the tanks with YS Engines. I was impressed with how thick, and rugged, the tank is. I was also impressed with how well the supply line, and seals, felt. They appear to be very tight, and well put together.
For comparison, I decided to call Hayes (which from what I can tell by our YS users, is the brand tank they use) and ask them what their wall thickness's are. The customer rep. asked me to hold and she would check with a tech. When she got back on the phone, she told me her tech. said he did not know, but that they are "pretty thick", and are blow molded.
The second concern was if you fly vertical, at a high rate of speed and for an extended period of time, then stall the plane and turn it over, there will be a point where the fuel goes to the top of the tank. The concern was that while you are in that split second area, of the fuel not being near the pickup, that it will stall the motor. I'll address this a little later, but to answer the question "NO, it will not stall".
O.k., so let's get started. You will see the following photo's The Roto Flow tank, the well used and abused Edge fuselage and the Du Bro 12 ounce tank that was replaced. I decided, after taking a serious look at the worn out fuselage, to replace it. There was some trim work that had to be done to fit the tank, but not much...just an ugly hack job on my part.
I talked with Donald about using a 2 or 3 line application...and after the discussion, I decided to use a 2 line application. That meant I needed to get a fuel dot. I didn't want to get a cheap one that would fail later. So I bought an Excel Fuel Filler Dot, from Chief Aircraft. It is a slimline product, and they have it available for gas and glow.
The Roto Flow tank has a brass nipple at the bottom (the supply line), a molded nipple at the top (the vent), and a third nipple in the middle. The third nipple has no predrilled hole.
When speaking with Donald, he said that if a three line application is needed then you would have to drill out that nipple. Donald assured me that when drilling that nipple, the molding will not go into the tank, but would just run back on the flutes of the drill and out, away, from the tank. Donald also told me that the way the tank is designed, you should not use any kind of clamps, or zip ties, on the tank. You will notice in one of my photo's that there is a zip tie on the supply line at the carburetor. I did that because for some reason the suggested size line slips off my motor, if it's not held down. But, there is nothing on the lines at the tank.
The other photo's are of the original 7.75 ounce tank and its weight, the 12 ounce Du Bro tank and its weight and the 12 ounce Roto Flow tank and it's weight. You will notice that the Roto Flow weighs a little more. Which was not a problem for me. I still had to add almost 4 ounces of weight to the nose, as I am not a 3d flyer.
The next set of photo's is the install. I think they are pretty self explanatory. Just trim an areas in the fuse you need to. Then, drop in the tank and slide on the hoses...that's it.
After all of this was completed, a few other cosmetic changes to the plane (and life slowing down a little), I took the plane to my club field. I videoed the plane running with the canopy off, and yes it sounds weird. You will notice some air bubbles at the top of the tank. To me there does not appear to be near the amount of air bubbles in the tank, as I have seen in other tanks. I watched a club member fly a 60 size profile Extra 260 with an external gas tank. I paid close attention to the tank, and noticed quite a bit of air bubbles.
Amazingly, there were no gas leaks from the initial install. The last couple of times I've played around with tanks, you have to put together, I've had to go back and tighten up things due to leaks.
The next video is of it running with the canopy on it, and yes that's how it should sound. I did have a problem, while testing on the stand, and needed to replace a worn glow plug (just forgot to do it before I started running the motor on the stand). No big deal, a 2 minute fix.
Let's talk about the claim of a harder hitting throttle response.I first posted on my club web site that I did not notice a harder hitting throttle response. However, after stepping away from the field, thinking about it, and looking at the video of my engine stand running...I did notice that it hits harder and quicker.
I also flew a 40 size Great Planes "Ugly" Stick with a O.S. .46, and stock tank. When comparing them, I noticed that the Stick had a hesitation when going from low to high throttle quickly. The Stick also had a sputter every now and then. Just for clarification, the Stick and motor are also brand new (and the motor has been broke in).
I have found that the hesitation and sputter, of a nitro motor, to be normal in the nitro world. I do remember the Edge behaving the same way before the Roto Flow gas tank was installed. So, yes, it does hit harder and quicker. This may be more important for you competition, and 3d flyers.
As I said before, there was concern about the tank losing prime during certain maneuvers. Well, I can tell you that I am an aggressive flyer. I tried everything I could to stall the motor (aside from hitting the throttle cut), from quick throttle changes to quick throttle changes accompanied with quick violent manuever changes. And there was never even a hesitation.
Let's face it, if you fly nitro, you have tried everything out there to clean and keep your plane clean (unless you just don't care). I flew the Edge a half dozen times, and flew the Stick a half dozen times.I immediately noticed that the Edge was cleaner than normal, MUCH cleaner. And was certainly much cleaner than the Stick. Yeah, I'm not a gear head and not really sure how the cleaner plane (from a gas tank change) works...but I Like It!
O.k., so here is the bottom line. Yes, it is more expensive than some other tanks. But, just having the peace of mind of not having a stuck clunk is enough for me. And if you are even a Sunday flyer, flying a 40 size ARF, you've probably already got $600 to $800 invested in a plane (once the build is done). What's another $30 or so, to have the security and peace of mind of not having a stuck clunk, and worse...a crash? I certainly don't want to loose a plane when a few more dollars might prevent it.
Not to mention the quicker throttle response, which again, could be important for you competition and 3d flyers.
Also, I am getting better fuel consumption. I noticed after I de-fueled my plane, that I got an extra 3-4 complete cranks out of the pump. I usually fly my plane for 8 minutes at a shot, with 4 minutes (or so) to spare. Now I've got even more fuel left over. I will be increasing my time to 10 minutes, maybe even up to 12.
Maintenance free, and a cleaner plane to boot, come on it's a no brainer. Yes, I will be getting a 10 ounce Roto Flow tank for my Stick. And, as soon as I am able to get my hands on that elusive 30cc 3D Hobby Shop Extra 330SC...Roto Flow will be onboard.
Donald also tells me these tanks will work for gas, kerosene (yes that means turbine jet flyers too) as well as glow. And even smoke systems. Basically any petroleum or alcohol based system.
You can reach Donald, at JL Products, at email@example.com
To see the products got to http://www.jlproducts.net/ProductRotoFlow.html
The tank sizes and prices are as follows: 10 ounce 29.95, 12 ounce 32.95, 14 ounce 33.95, 16 ounce 34.95, 20 ounce 38.95, 24 ounce 42.95, 32 ounce 45.95, 40 ounce 47.95, 50 ounce 49.95