Kevlar or plastic tank?
06-01-2017, 02:56 AM
#1
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Kevlar or plastic tank?
Hi guys,
I am building a Sebart Mini Avanti with a Kingtech K-45
This is my first turbine.
My question is should I put a plastic or Kevlar tank in it?
Obviously the Kevlar tank is the most expensive and I guess the lightest but… is it better?
Which is the best in a crash?
Love to get your feedback for a newbie.
I am building a Sebart Mini Avanti with a Kingtech K-45
This is my first turbine.
My question is should I put a plastic or Kevlar tank in it?
Obviously the Kevlar tank is the most expensive and I guess the lightest but… is it better?
Which is the best in a crash?
Love to get your feedback for a newbie.
06-01-2017, 03:13 AM
#2
Kevlar is lighter? Seems like the plastic tanks are lighter to me (e.g. Dubro given the same capacities.)
As far as crashworthiness, I guess it depends on the severity of the crash. I probably would not re-use a significantly crashed tank. I know that one of the dealers told me that the plastic was more crashworthy. But, then again, plastic is what he had in stock.
As far as crashworthiness, I guess it depends on the severity of the crash. I probably would not re-use a significantly crashed tank. I know that one of the dealers told me that the plastic was more crashworthy. But, then again, plastic is what he had in stock.
06-01-2017, 04:11 AM
#3
My Feedback: (48)
Definitely plastic! I spent years designing and testing automotive fuel systems. The reason that most autos now have plastic fuel tanks is because of crashworthiness. Kevlar tanks are oversold in this hobby. The shells are strong but they tend to split at the seams in a crash. You can beat on a properly designed plastic tank with a hammer and it won't break.
If you have any doubt get comparable kevlar and plastic tanks, fill them with water, and drop each one onto concrete from about 10 feet high.
If you have any doubt get comparable kevlar and plastic tanks, fill them with water, and drop each one onto concrete from about 10 feet high.
06-01-2017, 04:41 AM
#4
Regarding Kevlar, ... back in the day, NCR made a ton of money telling you what you had was junk, and putting a very high price on their new-fangled cash register's! It seems to me, that the flexibility of plastic would allow more impact w/o a rupture. I know the Kevlar tank I had in my Sprint that crashed basically disintegrated when it hit the ground. The biggest piece of that tank was maybe 3-5 square inches, at best. That was a spectacular crash! 
So,... for the replacement plane, I tried a plastic one and it was lighter.
So,... for the replacement plane, I tried a plastic one and it was lighter.
06-01-2017, 05:03 AM
#6
My Feedback: (24)
Plastic is tougher - no doubt, however you're limited in sizes and shapes; shapes especially when you're trying to cram as much juice in the plane as possible...
If I can find it, I use plastic but will go through the hassle of molding a tank if I have to. And, I'm about to have to...ugh.
If I can find it, I use plastic but will go through the hassle of molding a tank if I have to. And, I'm about to have to...ugh.
06-01-2017, 05:05 AM
#7
I can't speak for other manufacturerrs but I can tell you about CM Jets Kevlar tanks. They offer new form fitted tanks for the Mini Avanti. The advantage of this is you can get a higher volume of fuel in to the space compared to using a 'generic' plastic tank. Their older style was a generic shape that meant you had to cut out a small part of the inlet ducts (didn't cause much of an issue anyway), but the form fitted is a nice option. They can also make tanks that are part smoke, part fuel in one divided tank, and the tanks have a mount glued to the bottom meaning you can screw the tank straight down, no having to mess around with velcro straps etc. Kevlar tanks are available with a variety of fuel fittings, whereas plastic tanks are mainly just fuel bung style.
To my mind they obviously do the same job, just the custom tank adds some extra flexibility - if that is beneficial (and worth the extra cost) or not is up to the individuals choice. The Mini Avanti is pretty good access for whatever tank you want to try out, for scale jets the advantage of custom tanks is being able to get fuel capacity in to an akward shaped space.
To my mind they obviously do the same job, just the custom tank adds some extra flexibility - if that is beneficial (and worth the extra cost) or not is up to the individuals choice. The Mini Avanti is pretty good access for whatever tank you want to try out, for scale jets the advantage of custom tanks is being able to get fuel capacity in to an akward shaped space.
06-01-2017, 06:47 AM
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I think i just found it on the AMA docs. its because it is under 12 lbs. never really messed with a turbine under 12lbs been flying old AMT Olympus i think it weighs more than that 
06-01-2017, 02:02 PM
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Thanks for the great replies guys.
Looks like definitely plastic for me. I will sleep better knowing the plastic tank has less chance of disintegrating if I run out of talent and crash it!
In regards to the waiver, doesn’t mean you are not allowed to fly a mini Avanti turbine in the USA?
Looks like definitely plastic for me. I will sleep better knowing the plastic tank has less chance of disintegrating if I run out of talent and crash it!
In regards to the waiver, doesn’t mean you are not allowed to fly a mini Avanti turbine in the USA?
06-01-2017, 02:46 PM
#18
Last, even though part of the recent FAA efforts to make everyone register their models which was ruled null and void, the existing reg, what is it 336? Requires you to be part of a recognized group which adheres to a specific set of safety and operational requirements.
Short answer; if you've got a dry lakebed or something, you wouldn't be required to have the waiver, other than that you're pretty much required to have the waiver. Last, it's really for your own safety as well as others around you when you fly.....
06-02-2017, 10:55 AM
#20
My Feedback: (19)
From what I have seen about 10lbs dry. I was going to loan my 11lb Preceptor to my buddy for his waiver flight. The thought was to add 1 lb and then just running with a couple minutes of fuel for the waiver flight. He had an Opus which is hand launch and under 7.5 lbs. Ended up not getting his waiver though.
06-02-2017, 01:27 PM
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Note that the 12 lb minimum weight (dry) requirement only applies to the waiver qualification flight. Once the individual is turbine waivered he/she can fly any turbine powered fixed wing model as long as it complies with the AMA Safety Regulations for Model Aircraft Powered by Gas Turbines. It would be wise to review these regulations before offering advice regarding: Airframe Requirements, Flight Line Requirements and/or Pilot Requirements. These regs are available for review and download from AMA's website: www:modelaircraft.org.
Rgds,
Art ARRO, Turbine CD and waiver holder (Fixed Wing) since 2004.
Rgds,
Art ARRO, Turbine CD and waiver holder (Fixed Wing) since 2004.
06-02-2017, 01:52 PM
#22
My Feedback: (19)
Note that the 12 lb minimum weight (dry) requirement only applies to the waiver qualification flight. Once the individual is turbine waivered he/she can fly any turbine powered fixed wing model as long as it complies with the AMA Safety Regulations for Model Aircraft Powered by Gas Turbines. It would be wise to review these regulations before offering advice regarding: Airframe Requirements, Flight Line Requirements and/or Pilot Requirements. These regs are available for review and download from AMA's website: www:modelaircraft.org.
Rgds,
Art ARRO, Turbine CD and waiver holder (Fixed Wing) since 2004.
Rgds,
Art ARRO, Turbine CD and waiver holder (Fixed Wing) since 2004.
