buckeye320

Hello everyone,

As the title states, I'm new to RC planes and looking to learn. I have a specific question that I'm looking for advice on.

Here's the background:
I have come into the possession of a JetCat P80SE and want to set up a test bench for it for a project of mine. I have everything that comes with the kit, and have a plan for how I want it to look. I ordered a BVM UAT (did some research and saw that it was recommended) My main concern is that I want to ensure that I get it set up and running correctly.

My question(s):
1. I'm wondering if I can use any fluid storage tank for the MAIN fuel tank, or are there ones out there that are tailored for this type of thing? If there are, where?

2. When going through the manual, it says to use a brass tube for the UAT located at the center of the tank. Does tube diameter matter, and what would you recommend?

I realize that these are probably some dumb questions with obvious answers, but like I said, I want to make sure that I can get the engine running correctly. I appreciate any and all feedback!

JohnBuckner

My Feedback: (1)

Wow first let me welcome you to RCU. OK I am going to answer your two direct questions shortly.

But first since you posted these questions in the beginners forum and as you noted are a beginner to RC flight, you need to understand that Real turbine engines no matter how small are a disaster just waiting to happen and to consider attempting to fly one with no formal help and without learning to fly proficiently first is a going to result in a flaming hole in the ground somewhere. Even very proficient gas or electric propeller pilots have issues often on making the transition that no other type of type of propulsion presents.

Now not knowing what country you are in be aware that in the US if you fly a turbine at an AMA field you will have to have a 'turbine waiver' This requires a minimum number of flights and an actual flight test signed off by two turbine waiver pilots of which one must also hold a Contest Directors certificate.

Now to your questions and yes a test stand can be useful in learning a new type of turbine or operationg procedure. Here is a picture of one I was using just last weekend to learn the use of propane start procedures since my three other engines are kero start, procedures are very different.
For a test stand and the one in this picture is the Dubro fifty ounce with the gasoline plug as well as gas safe clunk line. This is a reasonable size for you stand and is reasonable in size for the snaller engines.

Question #1

Yes you can use a variety of tanks however the stoppers and clunk line materials must be gasoline, diesel, kerosene and Jet A safe. Yes those fuels can all be used but only for certain engines and with certain parameter changes on your GSU (ground support unit) see your manual.

Question #2

The BVM UAT that you ordered will have an appropriately sized pickup tube and fittings. Another popular UAT and less expensive is the one shown in the picture. It is the Hansen UAT.

Its hard to tell but you sound like you may be designing your own jet before evening learning how to fly and this is an even worse idea.

John

jester_s1

I'll second JohnBuckner's welcome to you, Buckeye320. Because I care about your safety and the safety of others, not to mention the reputation of this incredible hobby and your financial well being, I think it's prudent to say that your post sounds like the beginning of a significantly dangerous event, possibly even one that makes the evening news. If you want to get started into RC flying, get a trainer and an instructor and have yourself a blast. If you need help with finding an instructor, we can help with that too. If you are thinking of strapping that Jetcat to some other item, consider how a wet start, catastrophic internal failure, or wreck that leaks fuel could affect the rider and the surrounding area. Turbines are amazing pieces of technology, but they are also very unforgiving.

CARS II

My Feedback: (7)

Excellent advice.

buckeye320

Thank you guys for the replies and advice. I can certainly understand all of your concerns about trying to fly without experience. However, that was never my intention (It's too expensive and, more importantly, dangerous). My idea behind this is just to build a test stand for a project and to learn how these turbines perform/function. The farthest I wish to go with this project without experience is to mount it to a stand and run it in order to acquire data. I will keep you guys updated on my progress and hopefully get any more questions answered by you guys. John, thank you for your recommendations!

Gizmo-RCU

My Feedback: (27)

You got really good advice. Mine is do your testing outside in a safe place that will not burn

j.duncker

My Feedback: (2)

Rule 1 when working with jets is always have a CO 2 fire extinguisher to hand.

This is why.

https://youtu.be/jvCo3AnW0GM

JohnBuckner

My Feedback: (1)

http://www.modelaircraft.org/files/510-a.pdf

Excellent Buckeye320, it seems you have your head screwed on straight and there is nothing wrong with wanting to learn all about these amazing little machines. The engine I was working with last weekend (Jet Central 60 Super Bee) at full throttle runs at 181,000 rpm.

On the subject of fire extinguishers actually the AMA rules require the ABC CO-2 type but also a water base type must be on site, sometimes the club provides the water base but when we donated one to the club it quickly disappeared. The four jet guys at our club now each carries his own water base also. Those are mine in the picture and I make sure I always take this one also when none of the others are going to be there.

Dry chemical types should also not be used since this can damage your turbine. Co-2's will not harm the engines.

Here is a direct link to the Actual AMA turbine safety rules:

http://www.modelaircraft.org/files/510-a.pdf

Now if you are an AMA member you can access in the members only section of the AMA website a full listing of every single Turbine Waiver holder in the US. I think its something around two thousand folks and connecting with any of them on a local basis is an excellent first step in enjoying your engine.

Also another and popular way to do this is to visit any of the Jet Rallys that are all over the country now. I highly recommend networking in this way since this also opens up the possibility of obtain not only help but a source of all sorts of used equipment that may be difficult otherwise.

Curious if you obtained your engine used and how many hours?

Also since this is the airplane beginners forum its probably best for future turbine questions to go here: You will get lots of good answers there>

http://www.rcuniverse.com/forum/turbine-clinic-57/


Enjoy the Adventure

John

buckeye320

Thanks so much for that info. I will ensure I have both types of extinguishers with me when I run my tests. As for how I obtained the turbine, I was allowed to used it for a project at my school. They had two of these (one already set up by another student for a project that isn't functioning, and the one I have which is brand new in the box). This brings up a question I probably should've asked: Is there any specific procedure for running the engine for the very first time, or is it the same as described in the "startup" section of the manual?

JohnBuckner

My Feedback: (1)

The reason I inquired about your engine is since it is new in box that tells me you have the fuel pump, ICS or the (on board control unit) as well as the GSU (ground support unit) this is the device where all starting and operating parameters are set such as fuel pump voltage, glow plug voltage and so on. This also provide many other bits of information such as temperatures, RPM, total engine run time since new and each flight, battery capacity used for each run as well as diagnostics for a failed start.

Now as to is there a first start procedure different from what is in the book. Perhaps a break in procedure? the answer is no, none that I have ever heard of. Follow the startup info in your manual religiously. If new the individual startup parameters should already be set at a safe point but learn how to use that GSU and be sure the book initial parameters are set correctly. This is why I inquired if the engine was used.

Depending on your engine you may or may not (I have no Jetcat engines and they do vary) have to mount also on your board a main fuel solenoid and a propane solenoid. One all important item should be a main fuel manual shut off on your test stand and in an airplane from the UAT outlet to the fuel pump. This is the first action to take is to shut this off should a hot start occur in other words blowing excessive flames out the tailpipe.

Another item you are going to need is a leaf blower. Its funny when one first visits a Jet Rally it looks like some sort of gardners convention. The purpose of this is two fold first is safety, should a hot start occur after the fuel is shut off the blower is used directly into the intake, this first will blow out any remaining internal fire and by keeping the shaft spinning will prevent shock cooling of the blades. The second reason is when normal shut down is selected the ignition stops but the starter motor will keep cycling on and off until the engine gets down to around a hundred degrees. But if one uses the blower on shut down in the intake it will not require so much running of the starter motor and conserve the engine battery supply.

In the Jet forum I linked there is even a JetCat specific forum there for more specific info.

John

buckeye320

Hey guys. Just giving an update on my project. Got the engine mounted, but had a quick question: What would you recommend as receiver/throttle control? I think other than that, I have everything I need to wire electronics and fuel. I took John's advice on the Du-Bro 50 oz. tank (thank you for the recommendation!). Here's a picture of what I have so far. It's not much, but it's a start!

jester_s1

I might run a piece corner to corner on that bracket or either brace it diagonaily from the front corner to make sure it doesn't bend. You're the only one who knows how strong it really is, but without a triangle in the design you are relying solely on the stiffness of the metal to hold up the engine.

buckeye320

I made the mount out of 1/8'' x 1'' 6061T6 aluminum. I actually made it this way to allow for enough noticeable strain to be picked up by a strain gauge. I calculated the dimensions of the mount by using the maximum thrust of the engine (97N or 22LB) in order to get about 450 micro-strain. So there won't be near enough force to cause the mount to fail. Thanks for the idea though!

JohnBuckner

My Feedback: (1)

Hi Buckeye it interesting as your looking at it perhaps from an engineers point of view and I believe both Jester and I are simply looking at it from a practical point of view, Dude make it just like a set of seaplane floats, a simple "warren truss" with members working in tension from high at the exhaust end of the engine down to the torward low corner. That way you will be able to enjoy our engine at any power setting.

OK now to the question of how to control that throttle lead from your on board computer. First it can be done with a servo driver of some sort however this is difficult as you will have trouble setting to reliable trim positions and never be consistent.

The startup scenario with every engine I have worked with after all manual valves are opened the throttle and throttle trim shall be bottomed out. The start is initiated by raising the throttle trim to neutral and the auto start will begin. There is no need to touch the throttle or throttle trim agine through out the following ignition and ramp up to running stages. Shut down is always initiated by throttle full down and throttle trim to full down.

So the point here is you will need an RC system of some short to run the engine (Yes you can intiate start from you Ground support unit but its best you set up some RC link. If you look at the pictures of my test stand above you will see a Hitec Rx on the board and a five cell Nimh batt pack to power it. For runs the pack is simply plugged into any of the ports and the 'throttle lead' from the onboard computer is plugged into the #3 throttle port of the rx. Also on the board you can see a large two cell lipo (in this case an old RC car pack) to power the engine system and pump. This two cell lipo works on many of the older propane start engines but check your manual as many of newer kero starts engines require the higher voltage of a three cell life 9.9v.

John