JET LEGEND VIPER BUILD THREAD
#1151
Hi guys, I have finally started my build after a long delay. Ok, just a basic question. That loose air hose (on the pic), I believe is for the air tank..right? There's also another one on top of the tray ..I think for pressurising. In the old days I used to use bicycle valve but it's been a long time since I dealt with retracts.. so what pressure valves are you guys using nowadays? Oh, I forgot to mention I have a pro-wired version with all cables, hoses and pneumatics installed.
http://www.dreamworksrc.com/catalog/...ith-Checkvalve
These are helpful too. You will only need one.
http://www.dreamworksrc.com/catalog/Air-Gauge-Single
This is the best inflator I've ever used. Has a digital readout on the handle too. You will have to buy the 19volt battery separate, but if you get this, get a leaf blower too since the batteries are interchangeable. The leaf blower cuts down on how much your ECU battery is used cooling the turbine after shut down. I just stick the blower nozzle in the intake and let it blow cool air until the turbine completes the cooling cycle.
http://www.sears.com/craftsman-c3-19...1&blockType=G1
Best of luck!
Paul
#1152
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Thanks Paul, I like those quick couplings, might get some later on. I have the SMC press. gauge already installed and have bought very similar cordless air compressor, so I'm nearly set. Just have to get organized. Do you use those couplings for plugging retracts in the wing as well?
They seem quite chunky for that, don't know if there's enough space.
They seem quite chunky for that, don't know if there's enough space.
#1153
I do not use them for the wing connection. I use the metal screw together connection. Color coordinated, silver, gold and red. They do not take up much space and they make a great seal. Be careful not to pinch the lines when you push the wings on. If there is too much slack in the line, they will kink inside the wing. Don't leave a lot of excess line. Less is better. That's how my set up is done.
Paul
Paul
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Hi folks, here is one of my first K100g test runs. It will shortly find it's home in my new Viper.
Btw, does that start up look OK to you? I'm running diesel + kingtech oil.
https://www.youtube.com/watch?v=QmWpIihsk7E
Btw, does that start up look OK to you? I'm running diesel + kingtech oil.
https://www.youtube.com/watch?v=QmWpIihsk7E
#1155
Startup looks a little flamey, but then again I have only run my k100g on Kero and not Diesel. Maybe double check your ecu settings against the diesel parameters that are in the manual - reference pages 48, and 50. With a few slight tweaks you could hopefully reduce the cookout a bit.
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I'm going to start putting things together now but I'm still puzzled by all these fuel tank positioning combinations. I find hard to decide but to be honest I'd loved to use what's in there. I understand, stock tanks can make it quite nose heavy but if we position our gear to make it, say, 35mm aft with uat full, main tanks empty and gear retracted, where will then GG end up if we now fill the main tanks? Maybe I should ask different way. If you are using stock tanks only (no smoke system) with the above settings, is there a significant difference between first and the second part of the flight? Do you have to trim the elevator quite a lot?
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I'm going to start putting things together now but I'm still puzzled by all these fuel tank positioning combinations. I find hard to decide but to be honest I'd loved to use what's in there. I understand, stock tanks can make it quite nose heavy but if we position our gear to make it, say, 35mm aft with uat full, main tanks empty and gear retracted, where will then GG end up if we now fill the main tanks? Maybe I should ask different way. If you are using stock tanks only (no smoke system) with the above settings, is there a significant difference between first and the second part of the flight? Do you have to trim the elevator quite a lot?
Last edited by Vettster; 07-27-2014 at 01:38 PM.
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I'm going to start putting things together now but I'm still puzzled by all these fuel tank positioning combinations. I find hard to decide but to be honest I'd loved to use what's in there. I understand, stock tanks can make it quite nose heavy but if we position our gear to make it, say, 35mm aft with uat full, main tanks empty and gear retracted, where will then GG end up if we now fill the main tanks? Maybe I should ask different way. If you are using stock tanks only (no smoke system) with the above settings, is there a significant difference between first and the second part of the flight? Do you have to trim the elevator quite a lot?
John
Last edited by Jgwright; 07-28-2014 at 01:03 AM.
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Thanks John that's the answer I needed to hear for my own peace of mind. Interesting, you don't use UAT. I thought it was a must install to get a bubble free fuel delivery. You have a nice simple installation. That's what I'm aiming for.
#1161
Hi Fredo
"It has been debated many times before on this thread whether to stay with the twin 1500cc tanks or go with two smaller 800-950cc tanks at the back and one of the 1500cc at the front.
Fact is the Viper fly's "OK" with the 60-70mm + CG shift you get with the whole of its 3lt (6lbs!) of fuel that's some 230mm in front of the CG and its a testament to the airframe to be able to tolerate such a "large" CG shift.
Every one I know that fly's the Viper regularly has noticed a real difference this makes during the flight, particularly at take off were a nose heavy airframe "will" take a little longer to rotate. All 8+ Vipers I've built for myself and others plus a few others I've worked on over the past two seasons now have been upgraded to a three tank systems ether during the build or retrofitted. After all any airframe including the Viper cant fly worse with less or no CG shift that you can achieve with a three tank setup. Add to that its very little work to achieve especially with a new build, I just can not see a down side?.
You also get the added bonus of extra "free" space up front ether side of the front tank and it moving rearward by 40mm into the neck of the inlet duct closer to the CG. You also have the option of an extra 400ml of fuel if the 950cc JL smoke tanks are used and easy access to the front tank as the twin 1500 tanks are at best a little troublesome to remove.
My favourite method of plumping up the 2+1 tank setup is not to use a "T" but to use twin feeds into the main tank, this allows the fuel in the system to flow more easily. This can be easily achieved by using all three brass tubes into the bung, one from each rear tank and one going to the pump via a UAT.
I have recently found ta neater way to "plum up" this is to fit two 3-4mm tank fittings to the rear top of the main tank, this keeps the fuel lines very short and tidy. On my latest Viper I actually managed to fit the UAT along side the main tank, again making for a neat uncluttered install with easy access for maintenance. Felt and paper clunks do work and I often fit a felt clunk in the main tank but are no substitute for a good UAT and it is rare if not unheard of not to use one.
If your running a smaller turbine or don't feel the need to ferry fuel about or fly for 10 minuets at a time there's the option of fitting a smaller front tank, say 1-1200cc reducing the CG shift even further and still give good flight times. Do though no mater what setup you use check and check again the CG in all states of full or empty, I've flown happily with the CG at 50mm behind centre of wing tube but don't recommend going further back than 35mm.
What ever setup you use you will defiantly enjoy building and flying JL Viper, its got to be one of the nicest well behaved and best value sports scale airframes available today "probably"
"It has been debated many times before on this thread whether to stay with the twin 1500cc tanks or go with two smaller 800-950cc tanks at the back and one of the 1500cc at the front.
Fact is the Viper fly's "OK" with the 60-70mm + CG shift you get with the whole of its 3lt (6lbs!) of fuel that's some 230mm in front of the CG and its a testament to the airframe to be able to tolerate such a "large" CG shift.
Every one I know that fly's the Viper regularly has noticed a real difference this makes during the flight, particularly at take off were a nose heavy airframe "will" take a little longer to rotate. All 8+ Vipers I've built for myself and others plus a few others I've worked on over the past two seasons now have been upgraded to a three tank systems ether during the build or retrofitted. After all any airframe including the Viper cant fly worse with less or no CG shift that you can achieve with a three tank setup. Add to that its very little work to achieve especially with a new build, I just can not see a down side?.
You also get the added bonus of extra "free" space up front ether side of the front tank and it moving rearward by 40mm into the neck of the inlet duct closer to the CG. You also have the option of an extra 400ml of fuel if the 950cc JL smoke tanks are used and easy access to the front tank as the twin 1500 tanks are at best a little troublesome to remove.
My favourite method of plumping up the 2+1 tank setup is not to use a "T" but to use twin feeds into the main tank, this allows the fuel in the system to flow more easily. This can be easily achieved by using all three brass tubes into the bung, one from each rear tank and one going to the pump via a UAT.
I have recently found ta neater way to "plum up" this is to fit two 3-4mm tank fittings to the rear top of the main tank, this keeps the fuel lines very short and tidy. On my latest Viper I actually managed to fit the UAT along side the main tank, again making for a neat uncluttered install with easy access for maintenance. Felt and paper clunks do work and I often fit a felt clunk in the main tank but are no substitute for a good UAT and it is rare if not unheard of not to use one.
If your running a smaller turbine or don't feel the need to ferry fuel about or fly for 10 minuets at a time there's the option of fitting a smaller front tank, say 1-1200cc reducing the CG shift even further and still give good flight times. Do though no mater what setup you use check and check again the CG in all states of full or empty, I've flown happily with the CG at 50mm behind centre of wing tube but don't recommend going further back than 35mm.
What ever setup you use you will defiantly enjoy building and flying JL Viper, its got to be one of the nicest well behaved and best value sports scale airframes available today "probably"
Last edited by Mark Vandervelden; 07-28-2014 at 03:46 AM.
#1162
My Feedback: (11)
I have 400 foot grass runway, the tank configuration I use gets me off in that distance without yanking the elevator.
Also who "we"? You said we fly. You on a buddy box or does someone fly it for you?
The only puzzle is why people try to alter the stock tank position. I bought a second hand JLViperjet and the previous owner had removed the intakes. Luckily he had kept them so I glued them back in and installed the tanks in stock position. We fly with the CG (tanks empty) at the front corner of the rear hatch. You can conveniently lift the plane balancing at this point. We have had a number of flights now and not changed anything from the first flight we had. It needed no nose weight and the batteries are just in front of the tanks and on top of them. We have no noticeable CG shift in flight when the tanks are full or empty. The plane is very slippery and does not need a monster turbine, we are flying with a very early Simjet 18 lb thrust engine and we fly mostly at 1/2 throttle. Fuel consumption is as a result amazing. We can fly for 10 minutes or longer on the standard tanks. You will not see a UAT on the photos as I never use them. I fit pleated paper clunks in the tanks.
John
Also who "we"? You said we fly. You on a buddy box or does someone fly it for you?
Originally Posted by
Jgwright;11849883
Jgwright;11849883
The only puzzle is why people try to alter the stock tank position. I bought a second hand JLViperjet and the previous owner had removed the intakes. Luckily he had kept them so I glued them back in and installed the tanks in stock position. We fly with the CG (tanks empty) at the front corner of the rear hatch. You can conveniently lift the plane balancing at this point. We have had a number of flights now and not changed anything from the first flight we had. It needed no nose weight and the batteries are just in front of the tanks and on top of them. We have no noticeable CG shift in flight when the tanks are full or empty. The plane is very slippery and does not need a monster turbine, we are flying with a very early Simjet 18 lb thrust engine and we fly mostly at 1/2 throttle. Fuel consumption is as a result amazing. We can fly for 10 minutes or longer on the standard tanks. You will not see a UAT on the photos as I never use them. I fit pleated paper clunks in the tanks.
John
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Ok, I realise this is a subject discussed few times before, I'm a newbie to the jet world and it's not that easy to decide from the sea of options. I came from IMAC world and having idea of no, or minimal movement in CG appeals to me most to be honest. At the same time I was attracted to the stock set up, 'cos everything is there already plummed for you. I did read entire thread but as always there are lots of opinions and you just have to decide what suits most for you.
Thanks Mark for taking your time, appreciate that. It certainly does make sense. I really like the fact, you end up gaining space. I think you convinced me. I have a question though, if you don't mind. Could you draw a schematic of your 3 tank hook up?
Thanks Mark for taking your time, appreciate that. It certainly does make sense. I really like the fact, you end up gaining space. I think you convinced me. I have a question though, if you don't mind. Could you draw a schematic of your 3 tank hook up?
Last edited by fredo; 07-28-2014 at 04:44 AM.
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[QUOTE=Mark Vandervelden;11849906]Hi Fredo
"It has been debated many times before on this thread whether to stay with the twin 1500cc tanks or go with two smaller 800-950cc tanks at the back and one of the 1500cc at the front.
Fact is the Viper fly's "OK" with the 60-70mm + CG shift you get with the whole of its 3lt (6lbs!) of fuel that's some 230mm in front of the CG and its a testament to the airframe to be able to tolerate such a "large" CG shift.
Every one I know that fly's the Viper regularly has noticed a real difference this makes during the flight, particularly at take off were a nose heavy airframe "will" take a little longer to rotate. All 8+ Vipers I've built for myself and others plus a few others I've worked on over the past two seasons now have been upgraded to a three tank systems ether during the build or retrofitted. After all any airframe including the Viper cant fly worse with less or no CG shift that you can achieve with a three tank setup. Add to that its very little work to achieve especially with a new build, I just can not see a down side?.
You also get the added bonus of extra "free" space up front ether side of the front tank and it moving rearward by 40mm into the neck of the inlet duct closer to the CG. You also have the option of an extra 400ml of fuel if the 950cc JL smoke tanks are used and easy access to the front tank as the twin 1500 tanks are at best a little troublesome to remove.
My favourite method of plumping up the 2+1 tank setup is not to use a "T" but to use twin feeds into the main tank, this allows the fuel in the system to flow more easily. This can be easily achieved by using all three brass tubes into the bung, one from each rear tank and one going to the pump via a UAT.
I have recently found ta neater way to "plum up" this is to fit two 3-4mm tank fittings to the rear top of the main tank, this keeps the fuel lines very short and tidy. On my latest Viper I actually managed to fit the UAT along side the main tank, again making for a neat uncluttered install with easy access for maintenance. Felt and paper clunks do work and I often fit a felt clunk in the main tank but are no substitute for a good UAT and it is rare if not unheard of not to use one.
If your running a smaller turbine or don't feel the need to ferry fuel about or fly for 10 minuets at a time there's the option of fitting a smaller front tank, say 1-1200cc reducing the CG shift even further and still give good flight times. Do though no mater what setup you use check and check again the CG in all states of full or empty, I've flown happily with the CG at 50mm behind centre of wing tube but don't recommend going further back than 35mm.
What ever setup you use you will defiantly enjoy building and flying JL Viper, its got to be one of the nicest well behaved and best value sports scale airframes available today "probably"
Fredo.. Entering the world of Turbines and immediately taking short cuts (the easy way) does not seem to be the right road to a long and successful turbine flying career. I would seriously take the advice of Mark Vandervelden posted above. In my personal opinion a UAT is mandatory no matter what configuration you are using. Turbines do NOT like bubbles and the UAT's sol purpose is to eliminate the possibility of bubbles getting to the engine and causing a flame out. Its a very cheap form of insurance to make sure your engine wont quit.
"It has been debated many times before on this thread whether to stay with the twin 1500cc tanks or go with two smaller 800-950cc tanks at the back and one of the 1500cc at the front.
Fact is the Viper fly's "OK" with the 60-70mm + CG shift you get with the whole of its 3lt (6lbs!) of fuel that's some 230mm in front of the CG and its a testament to the airframe to be able to tolerate such a "large" CG shift.
Every one I know that fly's the Viper regularly has noticed a real difference this makes during the flight, particularly at take off were a nose heavy airframe "will" take a little longer to rotate. All 8+ Vipers I've built for myself and others plus a few others I've worked on over the past two seasons now have been upgraded to a three tank systems ether during the build or retrofitted. After all any airframe including the Viper cant fly worse with less or no CG shift that you can achieve with a three tank setup. Add to that its very little work to achieve especially with a new build, I just can not see a down side?.
You also get the added bonus of extra "free" space up front ether side of the front tank and it moving rearward by 40mm into the neck of the inlet duct closer to the CG. You also have the option of an extra 400ml of fuel if the 950cc JL smoke tanks are used and easy access to the front tank as the twin 1500 tanks are at best a little troublesome to remove.
My favourite method of plumping up the 2+1 tank setup is not to use a "T" but to use twin feeds into the main tank, this allows the fuel in the system to flow more easily. This can be easily achieved by using all three brass tubes into the bung, one from each rear tank and one going to the pump via a UAT.
I have recently found ta neater way to "plum up" this is to fit two 3-4mm tank fittings to the rear top of the main tank, this keeps the fuel lines very short and tidy. On my latest Viper I actually managed to fit the UAT along side the main tank, again making for a neat uncluttered install with easy access for maintenance. Felt and paper clunks do work and I often fit a felt clunk in the main tank but are no substitute for a good UAT and it is rare if not unheard of not to use one.
If your running a smaller turbine or don't feel the need to ferry fuel about or fly for 10 minuets at a time there's the option of fitting a smaller front tank, say 1-1200cc reducing the CG shift even further and still give good flight times. Do though no mater what setup you use check and check again the CG in all states of full or empty, I've flown happily with the CG at 50mm behind centre of wing tube but don't recommend going further back than 35mm.
What ever setup you use you will defiantly enjoy building and flying JL Viper, its got to be one of the nicest well behaved and best value sports scale airframes available today "probably"
Fredo.. Entering the world of Turbines and immediately taking short cuts (the easy way) does not seem to be the right road to a long and successful turbine flying career. I would seriously take the advice of Mark Vandervelden posted above. In my personal opinion a UAT is mandatory no matter what configuration you are using. Turbines do NOT like bubbles and the UAT's sol purpose is to eliminate the possibility of bubbles getting to the engine and causing a flame out. Its a very cheap form of insurance to make sure your engine wont quit.
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[QUOTE=Vettster;11849952]
I have had many (32) jet planes over the years and have never fitted a UAT to any of them and not had problems with engine flameouts. The pleated paper filter does the same job but does not need a separate tank that is up front and permanently full of fuel. The pleated paper filter will suck the tank almost dry before the engine quits.
http://www.gbr-jet.com/catalog/produ...9imo1i2ou5v6g4
However if you feel the need for a UAT then buy one, but do make sure that it does not leak air through the fittings or the cap.
Essyou35 No I do not fly myself. Dave Wilde does all the flying for me we are a team of 2. I find building the planes and building engines and getting things prepped is enough for me besides I am no good at flying!
John
Hi FredoFredo.. Entering the world of Turbines and immediately taking short cuts (the easy way) does not seem to be the right road to a long and successful turbine flying career. I would seriously take the advice of Mark Vandervelden posted above. In my personal opinion a UAT is mandatory no matter what configuration you are using. Turbines do NOT like bubbles and the UAT's sol purpose is to eliminate the possibility of bubbles getting to the engine and causing a flame out. Its a very cheap form of insurance to make sure your engine wont quit.
http://www.gbr-jet.com/catalog/produ...9imo1i2ou5v6g4
However if you feel the need for a UAT then buy one, but do make sure that it does not leak air through the fittings or the cap.
Essyou35 No I do not fly myself. Dave Wilde does all the flying for me we are a team of 2. I find building the planes and building engines and getting things prepped is enough for me besides I am no good at flying!
John
#1167
Hi Fredo
Ive made a quick sketch of a three tank setup for you here, its not pretty but hopefully its clear.
Its good practise to keep the two vent lines from the rear tanks equal to the "T" and the two feed lines to the main take should also be equal.
Use at least 3mm ID Tygon or Tygon type fuel line to hook it all up and for the clunk lines, Try to keep the lines short but don't force and bend them too tightly in case they kink.
You can of course use 6mm festo clear fuel line, its much more resistant to collapsing but its harder to get round the bends neatly.
I use a HD Yellow fuel line from China, Its a little stiffer than Tygon, but I find it works far better and lasts "years" longer and at 1/3 the cost but stick with what you know is good.
The two clunks in the rear tanks can be bored out the max allowed by there nipple, hopefully at least 3mm, the main tank would benefit from a felt filter like the Gas guys use.
Wire tie the fuel lines to the brass tube both outside and inside the tanks, you can solder on a barb but I've found it unnecessary with my fuel lines and usually struggle to remove them.
The brass tube you get with the JL tanks is a good size but be sure to de-bur the ends and are not restricted were there cut to length.
Using two tank fitting-nipples on the back rear/top of the main tank instead of a 3 tube bung as per my earlier post keeps the lines very sort and out of the way, a bit fiddly to fit but worth it.
Of course the two air vents into the rear tanks and feeds into the front tank if used must go to the top of the tanks.
Make sure the ends of the vents inside if brass tubes are used have 5mm clearance from the top of the tank, if the tanks get crushed or collapse slightly they then can not be blocked off.
The fuel is finally drawn off the front tank to the pump via a propriety UAT, BVM, Intairco, MAP etc these have a twin top vent to which the fuel is then fed.
The second vent on the UAT is then used to fill all the tanks and is effectively back feeds through the three tanks till it comes out the main vent placed under or low on the airframe.
This fill line to the UAT will then have to be sealed effectively wile the turbine is running and must not allow air to be drawn in, I use a Festo end cap.
Ive made a quick sketch of a three tank setup for you here, its not pretty but hopefully its clear.
Its good practise to keep the two vent lines from the rear tanks equal to the "T" and the two feed lines to the main take should also be equal.
Use at least 3mm ID Tygon or Tygon type fuel line to hook it all up and for the clunk lines, Try to keep the lines short but don't force and bend them too tightly in case they kink.
You can of course use 6mm festo clear fuel line, its much more resistant to collapsing but its harder to get round the bends neatly.
I use a HD Yellow fuel line from China, Its a little stiffer than Tygon, but I find it works far better and lasts "years" longer and at 1/3 the cost but stick with what you know is good.
The two clunks in the rear tanks can be bored out the max allowed by there nipple, hopefully at least 3mm, the main tank would benefit from a felt filter like the Gas guys use.
Wire tie the fuel lines to the brass tube both outside and inside the tanks, you can solder on a barb but I've found it unnecessary with my fuel lines and usually struggle to remove them.
The brass tube you get with the JL tanks is a good size but be sure to de-bur the ends and are not restricted were there cut to length.
Using two tank fitting-nipples on the back rear/top of the main tank instead of a 3 tube bung as per my earlier post keeps the lines very sort and out of the way, a bit fiddly to fit but worth it.
Of course the two air vents into the rear tanks and feeds into the front tank if used must go to the top of the tanks.
Make sure the ends of the vents inside if brass tubes are used have 5mm clearance from the top of the tank, if the tanks get crushed or collapse slightly they then can not be blocked off.
The fuel is finally drawn off the front tank to the pump via a propriety UAT, BVM, Intairco, MAP etc these have a twin top vent to which the fuel is then fed.
The second vent on the UAT is then used to fill all the tanks and is effectively back feeds through the three tanks till it comes out the main vent placed under or low on the airframe.
This fill line to the UAT will then have to be sealed effectively wile the turbine is running and must not allow air to be drawn in, I use a Festo end cap.
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Thanks heaps Mark. That schematic looks simple enough. Doesn't that main tank need to be vented as well? Just curious.
Vettster, I don't know where you get the idea I'm taking short cuts. I never said I won't use UAT.
Vettster, I don't know where you get the idea I'm taking short cuts. I never said I won't use UAT.
#1171
Hi Fredo
The main tank once the system is filled draws only fuel from the two rear tanks and then air once there empty, It must remain a sealed unit and not draw any air until the rear tanks are empty or the rear tanks will not empty at all.
This is why the lines from the rear tanks and there vents must be equal so they empty symmetrically, If one rear tank empty's before the other it will continue to slowly draw from the remaining "fuller" tank but at a much slower rate.
This is because air will then be drawn through the empty tank easier than fuel can be from the part full one, in practice and in my experience both rear tanks are usually dry at the end of the flight, lets hope the main one is not
An other option and one "I don't recommend" is to plumb all the tanks in series IE empty one after the other, this creates quit a high draw for the pump when all the tanks are full and a comparatively low draw when only the front tank is full.
I have tried it and even on a well plumbed and as free flowing setup as feasible, first makes the poor little on-board pump work hard and then confuses it as the draw reduces which can lead to an uneven run, so for me its never a first option.
All the best Mark V
The main tank once the system is filled draws only fuel from the two rear tanks and then air once there empty, It must remain a sealed unit and not draw any air until the rear tanks are empty or the rear tanks will not empty at all.
This is why the lines from the rear tanks and there vents must be equal so they empty symmetrically, If one rear tank empty's before the other it will continue to slowly draw from the remaining "fuller" tank but at a much slower rate.
This is because air will then be drawn through the empty tank easier than fuel can be from the part full one, in practice and in my experience both rear tanks are usually dry at the end of the flight, lets hope the main one is not
An other option and one "I don't recommend" is to plumb all the tanks in series IE empty one after the other, this creates quit a high draw for the pump when all the tanks are full and a comparatively low draw when only the front tank is full.
I have tried it and even on a well plumbed and as free flowing setup as feasible, first makes the poor little on-board pump work hard and then confuses it as the draw reduces which can lead to an uneven run, so for me its never a first option.
All the best Mark V
#1172
Fredo,
I agree with John Wright on why the 'as designed' setup is being altered for the fuel system. I don't think you have to make this too hard. Although my Viper only has the maiden done, I watched Mike Lin fly his Viper with 'stock' setup on fuel tanks with a 140 size turbine with no issues the entire weekend at Tucson back in March. For the placement of batteries, pump, etc., I can send you pics of my setup, if desired. I basically followed what Global Jet Club does on their turnkey option and it worked fine.
Regards,
Gus
I agree with John Wright on why the 'as designed' setup is being altered for the fuel system. I don't think you have to make this too hard. Although my Viper only has the maiden done, I watched Mike Lin fly his Viper with 'stock' setup on fuel tanks with a 140 size turbine with no issues the entire weekend at Tucson back in March. For the placement of batteries, pump, etc., I can send you pics of my setup, if desired. I basically followed what Global Jet Club does on their turnkey option and it worked fine.
Regards,
Gus
#1173
My Feedback: (11)
No this is not the extreme jets version. This is the jet legend version AKA global jet club viper.
It will take off fine on 400 foot runways that are grass if you either fly with a smoke system (I assume) or use the smoke tanks as fuel tanks. This will adjust the CG back for takeoff to keep the nose up on the grass take off. Otherwise the front gear sags due to the drag on the grass and your nose has a negative AOA.
I cant say that it WONT take off on that runway with the tanks all forward but mine with the CG back several inches uses up that runway a lot.
I did try once to take off with only the main front tank as I was out of fuel and only had enough to fuel that.
Despite being lighter, I had to aboart and it was almost a disaster, it would not rotate at its normal spot.
That is the only anecdotal evidence I have.
It will take off fine on 400 foot runways that are grass if you either fly with a smoke system (I assume) or use the smoke tanks as fuel tanks. This will adjust the CG back for takeoff to keep the nose up on the grass take off. Otherwise the front gear sags due to the drag on the grass and your nose has a negative AOA.
I cant say that it WONT take off on that runway with the tanks all forward but mine with the CG back several inches uses up that runway a lot.
I did try once to take off with only the main front tank as I was out of fuel and only had enough to fuel that.
Despite being lighter, I had to aboart and it was almost a disaster, it would not rotate at its normal spot.
That is the only anecdotal evidence I have.
Last edited by essyou35; 07-28-2014 at 03:45 PM.
#1174
Join Date: Sep 2007
Location: Beeton, Ontario, CANADA
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John Wright... Im not against trying new things. Its just takes some time to convince people, myself included. To show you that Im not arguing for the sake of arguing... Ive decided to give your fuel clunk/no UAT idea a try. I took the felt filter out of my UAT and installed it into the fuel tank. Its plenty heavy and does not need the weight on the end. I'll be maidening the Viper very soon. Lets see how it goes.
Last edited by Vettster; 07-28-2014 at 03:56 PM.