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''Long range tip tanks''
- Thread starter gabb
- Start date
Smilin' Jack
Well Known Member
Do you have a link?
Jack
Jack
High_Flyer
Well Known Member
$3,650.00!!!
i think that's very reasonable for an extra 20 gallons of fuel.....that goes a long way in these planes
I agree
When we picked up our RV-6A kit in a truck we rented in Portland I stopped in Grants Pass on the way down to southern California (Laguna Hills - Orange County) and picked up a set of tip tanks from Farn Reed (who has since died in a plane crash I'm told) and installed them as part of the original build. They are aluminum and provide 17 gallons or 1.6 hours of endurance to our plane. They go between the end of the basic wing and the actual wing tip adding 18" to the total wingspan. These new tips retain the original aircraft design physical envelope and that is a plus from a stress point of view. I did see a post about them being made of a material that has to be considered as corrosive adjacent to aluminim - I know nothing personal about this as I have never had a need to study it. I think the thread said there is some surface treatment or coating you can use to reduce or eliminate the problem. Back to my title thought for trips (I apparently do not have the bladder problem some folks talk about) reducing the number of times I have to land and refuel is worth much more than the cost of these tanks. When I fly to southern California from Fayetteville, Arkansas I refuel at Tucumcari and Prescott. If I go there in June without the tip tanks because of the very busy SARL racing schedule this year I will probably stop at Amarillo, Albuquerque and Winslow. It takes about two days of leisurly effort to go from race to cruise configuration.
Bob Axsom
When we picked up our RV-6A kit in a truck we rented in Portland I stopped in Grants Pass on the way down to southern California (Laguna Hills - Orange County) and picked up a set of tip tanks from Farn Reed (who has since died in a plane crash I'm told) and installed them as part of the original build. They are aluminum and provide 17 gallons or 1.6 hours of endurance to our plane. They go between the end of the basic wing and the actual wing tip adding 18" to the total wingspan. These new tips retain the original aircraft design physical envelope and that is a plus from a stress point of view. I did see a post about them being made of a material that has to be considered as corrosive adjacent to aluminim - I know nothing personal about this as I have never had a need to study it. I think the thread said there is some surface treatment or coating you can use to reduce or eliminate the problem. Back to my title thought for trips (I apparently do not have the bladder problem some folks talk about) reducing the number of times I have to land and refuel is worth much more than the cost of these tanks. When I fly to southern California from Fayetteville, Arkansas I refuel at Tucumcari and Prescott. If I go there in June without the tip tanks because of the very busy SARL racing schedule this year I will probably stop at Amarillo, Albuquerque and Winslow. It takes about two days of leisurly effort to go from race to cruise configuration.
Bob Axsom
Extra Gas
Unless you plan on long overwater flights, what's the advantage of 20 gallons of extra gas? I find that the endurance of my -8A already exceeds the endurance of both my bladder and my back and leg muscles. I easily get 4+ hours with comfortable reserves at 8 gph cruise.
Unless you plan on long overwater flights, what's the advantage of 20 gallons of extra gas? I find that the endurance of my -8A already exceeds the endurance of both my bladder and my back and leg muscles. I easily get 4+ hours with comfortable reserves at 8 gph cruise.
longranger
Well Known Member
Question already answered: Not all bladders are created equal. Even dismissing that, who says you have to use all your range in one leg?
Very nice to either overfly that expensive fuel to get to cheap(er) fuel 200 miles down the road, or stop and relieve your "personal discomfort" and press on without adding fuel. Lots of flexibility.Question already answered: Not all bladders are created equal. Even dismissing that, who says you have to use all your range in one leg?
I desire IFR reserves, that's my goal for the extra fuel. I do not want to overfly areas with LIFR if I cannot backtrack to get to VFR, having extra fuel gives me options
flyboy1963
Well Known Member
options.......are limited?
So..... I'd love to have lots of fuel, for that peace of mind, trips out & back where there may not be fuel etc.
....but just how far will me and my cat want to travel with ZERO baggage? My numbers show that with this 'extended' full fuel load, I can't carry much else without being over gross, so what's the point? ( or is fuel lighter in Aus?
(I'm assuming that their listing for tanks for 4,6,7,8,9 takes into account the different airfoils?)
So..... I'd love to have lots of fuel, for that peace of mind, trips out & back where there may not be fuel etc.
....but just how far will me and my cat want to travel with ZERO baggage? My numbers show that with this 'extended' full fuel load, I can't carry much else without being over gross, so what's the point? ( or is fuel lighter in Aus?
(I'm assuming that their listing for tanks for 4,6,7,8,9 takes into account the different airfoils?)
longranger
Well Known Member
So..... I'd love to have lots of fuel, for that peace of mind, trips out & back where there may not be fuel etc.
....but just how far will me and my cat want to travel with ZERO baggage? My numbers show that with this 'extended' full fuel load, I can't carry much else without being over gross, so what's the point? ( or is fuel lighter in Aus?
Again, more flexibility. I'm from the school of thought that if you can fill both the tanks and the seats, the airplane isn't as flexible as it could be. Solo? Fill the tanks and maximize range or minimize stops. Passenger? Fuel to gross (a whole 'nuther discussion
) and take what you get. (For two folks my size, you'd have to do this in a standard-range RV anyway. ) The RV-10 could benefit from this concept even more than the -7...Correct. From the AdvancedAero web page: Carbon Fiber extended range tip tanks to suit RV 4, 6, 7, 8 and 9. That is only two different tank models, as the first four listed all have the same airfoil.
Mile High Relic
Well Known Member
I can add my wife, 100lb of baggage, the dog and another 12 gallons and still be under the gross on my data plate. Benefits of being short, I guess. That doesn't include the weight of the tanks though. The ones at the link below are on my long list of possible upgrades and are ~10 lbs. With the weight of the tanks maybe I only get an extra 10 gallons, or I have to leave the Dachshund at home.
http://www.safeair1.com/fueltanks/rv6ertanks.php
I have a 6, so I apologize for posting in the 7 section, but here is the link for the 7 tanks.
http://www.safeair1.com/fueltanks/rv7ertanks.php
http://www.safeair1.com/fueltanks/rv6ertanks.php
I have a 6, so I apologize for posting in the 7 section, but here is the link for the 7 tanks.
http://www.safeair1.com/fueltanks/rv7ertanks.php
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Captain Avgas
Well Known Member
I don't think they're any more expensive than the original Jon Johansen tip tanks. And they're probably lighter....being carbon fibre.
Jamie Aust
Well Known Member
I had a look at these last weekend. At 7kg each, thats a lot of extra weight on the tips, without fuel yet.
If I had $4500 to spend, I would look at making all the leading edge a wet wing.
Thats just me, you may like this setup. I find 2.5 - 3 hrs is all I can spend in the RV till I need a pit stop.
If I had $4500 to spend, I would look at making all the leading edge a wet wing.
Thats just me, you may like this setup. I find 2.5 - 3 hrs is all I can spend in the RV till I need a pit stop.
I had a look at these last weekend. At 7kg each, thats a lot of extra weight on the tips, without fuel yet.
If I had $4500 to spend, I would look at making all the leading edge a wet wing.
Thats just me, you may like this setup. I find 2.5 - 3 hrs is all I can spend in the RV till I need a pit stop.
I did that to mine for a lot less than $4500 - more like about $600 additional, but probably another 50 hours build time. I've got the standard-build wing tanks, and then about 9" for a mid-wing bay where I have a transfer pump to move fuel from outboard to inboard, then the rest of the outboard leading edge is another tank with flow-through venting into the inboard main. Lowest point on the outboard tank vents into the highest point in the inboard, for automatic fuel transfer as you burn from the inboard. The transfer pump is for "what-if", standard Facet low-pressure with it's own transfer line. For maximum fuel capacity, the inboard would be filled first, then the outboard, the transfer pump would be turned on pushing fuel inboard where it would backflow through the vent line into the outboard, displacing all the air bubble in the inboard, then you can top off the outboard and head out over the ocean. Fuel filler caps with good seals would obviously be required - but shouldn't they be anyway?
This is not new territory, but it is definitely the road less traveled.
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Can't get off the fence
I've been almost ready to pull the trigger on a set of these for some time, but haven't quite been able to get myself to do it. Cost is the main reason, but the changes to my VOR antenna and wingtip lights also weigh in (additional cost and time).
For my mission, more fuel capacity is unquestionably at the top of the list of utility-enhancing upgrades. My -4 has a 32 gallon capacity, which means IFR range is pretty pitiful if after I subtract time to an alternate and a 1-hour reserve. The additional 19 gallons would work wonders.
Right now, I'm considering two other options:
Retrofitting outboard leading edge tanks (labor intensive, but huge range for solo IFR XC)
Making my own tip tanks (not too hard, and a fraction of the cost if the Pre-made ones)
Safe-air tanks get high marks, but simply don't add enough capacity for my needs.
I'd love to hear from others who have made a decision one way or another.
I've been almost ready to pull the trigger on a set of these for some time, but haven't quite been able to get myself to do it. Cost is the main reason, but the changes to my VOR antenna and wingtip lights also weigh in (additional cost and time).
For my mission, more fuel capacity is unquestionably at the top of the list of utility-enhancing upgrades. My -4 has a 32 gallon capacity, which means IFR range is pretty pitiful if after I subtract time to an alternate and a 1-hour reserve. The additional 19 gallons would work wonders.
Right now, I'm considering two other options:
Retrofitting outboard leading edge tanks (labor intensive, but huge range for solo IFR XC)
Making my own tip tanks (not too hard, and a fraction of the cost if the Pre-made ones)
Safe-air tanks get high marks, but simply don't add enough capacity for my needs.
I'd love to hear from others who have made a decision one way or another.
Captain Avgas
Well Known Member
I had a look at these last weekend. At 7kg each, thats a lot of extra weight on the tips, without fuel yet.
Thats just me, you may like this setup. I find 2.5 - 3 hrs is all I can spend in the RV till I need a pit stop.
Standard tips are approx 2.9 kg each. The Johanson tip tanks were approx 5.5kg each, thus adding only roughly 2.6 kg per side. I'd be surprised if the carbon fibre tip tanks would weigh more than the Johansen tanks. Thus the total increase in mass is not that great. On the other hand any increase in mass at the crucial wing tip area could (and probably will) affect spin recovery characteristics.
In Australia it's not so much about having extra fuel simply to enable really long legs that test your bladder....it's about going to destinations that do not have Avgas available (or have it available but want to charge $2.50-3.00 litre). Other places want to sting you up to $100 for a call-out fee and can make you wait hours for service. Some places without bowsers won't sell less than a full drum. It can be mighty handy at times not to have to refuel.
bird
Well Known Member
just thinking
Has anyone considered looking into a bladder system for extra fuel storage. I am familiar with the bladder system in a beech baron. Maybe this could work for a rv. I don't know about the price to have one fabricated for our rv's. It's just goodyear rubber, shouldn't break the bank. Some work would have to be done but it is possible. Just thinking outside the box.
bird
Has anyone considered looking into a bladder system for extra fuel storage. I am familiar with the bladder system in a beech baron. Maybe this could work for a rv. I don't know about the price to have one fabricated for our rv's. It's just goodyear rubber, shouldn't break the bank. Some work would have to be done but it is possible. Just thinking outside the box.
bird
eats up the baggage compartment space, or do you mean installed in the wings somehow?
Jamie Aust
Well Known Member
I dont see the logic in that.
You are happy to spend $4500, just to save $3 a litre ?
Thats all im going to say about this topic, I dont want it to start into a bash. Build what ever makes you feel good and enjoy it !
Captain Avgas
Well Known Member
Logic, like beauty, is often in the eyes of the beholder. I note that back in 2005 you suggested to an RV builder on this forum that he consider installing an air-conditioning system in his RV7A to help rectify his aft CG problem.
longranger
Well Known Member
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Gravity feed from tip tanks
Hhmm, lots of opinions about extra fuel capacity. I'm building for IFR and making my own tip tanks (lining the stock tips with vinyl ester and another layer of glass before adding intermediate baffles and walls).
I don't want the weight/complexity/work of an extra transfer pump, so my question is, is there enough positive pressure from the forward facing vent line to push fuel 2" up from the bottom of the tip tank over the edge of the first wing rib lightening hole (so I don't have to drill holes along the bottom of the wing ribs before the last wing skin goes on)?
F1 Rocket (VH-FLY)
Under construction (5 years, 2100 hours so far)
www.mykitlog.com/RockFLY
Hhmm, lots of opinions about extra fuel capacity. I'm building for IFR and making my own tip tanks (lining the stock tips with vinyl ester and another layer of glass before adding intermediate baffles and walls).
I don't want the weight/complexity/work of an extra transfer pump, so my question is, is there enough positive pressure from the forward facing vent line to push fuel 2" up from the bottom of the tip tank over the edge of the first wing rib lightening hole (so I don't have to drill holes along the bottom of the wing ribs before the last wing skin goes on)?
F1 Rocket (VH-FLY)
Under construction (5 years, 2100 hours so far)
www.mykitlog.com/RockFLY
No extra pump on mine
My tip tank pick ups are made of 3/8" aluminum tubing just like the main tanks. It is connected to a bulkhead fitting on the side of the tank and extends to the bottom of the tank for the fuel entry (pickup) point. another 3/8" aluminum tube is connected to the bulkhead fitting on the outside of the tank and it runs inboard on the forward side of the spar and behind the main tank to the root whewre it forms a service loop and connects to a bulkhead fitting on the side of the fuselage. Inside the fuselage another 3/8" tube extends from the fitting to a fitting on my one of a kind personally built console. A hose inside the console connects to a filter and a hose on the outlet of the filter goes to a two port fuel valve (either one or the other tip tanks is selected at all times at this point in the tip supply part of the fuel system) dedicated to the two tip tanks. The output of this valve is connected to one inlet port of a four position main fuel valve (selects Left main, right main, tips or all fuel off). The output of the main fuel valve is connected to a Facet electric fuel pump, the output of this pump is connected by 3/8" aluminum tube to a "T" fitting. One outlet of the "T" goes to a primer solenoid which is connected by 1/8" aluminum tube to a bulkhead fitting high on the firewall and the other outlet is connected by a 3/8" aluminum tube to a bulkheaad fitting high up on the firewall. On the forward side of the firewall the primer path is connected to the primer ports on cylinders 1,2 & 4 through 1/8" aluminum, and copper tubing with full circle strain relief loops and "T"s and silver soldered primer fittings. The main fuel path is through a hose to the engine driven mechanical pump and from there to the carburetor input. Those are the only two fuel pumps in the system and they are in series and they both serve what ever tank in selected. After takeoff the electric fuel bump is turned off and all fuel pumping is done by the engine driven mechanical pump. No pumps are added for the tip tanks. In short race configuration I remove the tip tanks because they go between the wing tip and the stock tips and add 18" to the wing span and reduce the maximum speed by 3 knots. The only special precaution with tip tanks is to not select one for takeoff because if they are not full the fuel will move to the rear of the tip and if the fuel quantity is low enough and you climb out at a high angle it will leave the pickup tube sucking air.
My system works perfectly, never a problem in 9 calendar years and 900+ operating hours.
Bob Axsom
My tip tank pick ups are made of 3/8" aluminum tubing just like the main tanks. It is connected to a bulkhead fitting on the side of the tank and extends to the bottom of the tank for the fuel entry (pickup) point. another 3/8" aluminum tube is connected to the bulkhead fitting on the outside of the tank and it runs inboard on the forward side of the spar and behind the main tank to the root whewre it forms a service loop and connects to a bulkhead fitting on the side of the fuselage. Inside the fuselage another 3/8" tube extends from the fitting to a fitting on my one of a kind personally built console. A hose inside the console connects to a filter and a hose on the outlet of the filter goes to a two port fuel valve (either one or the other tip tanks is selected at all times at this point in the tip supply part of the fuel system) dedicated to the two tip tanks. The output of this valve is connected to one inlet port of a four position main fuel valve (selects Left main, right main, tips or all fuel off). The output of the main fuel valve is connected to a Facet electric fuel pump, the output of this pump is connected by 3/8" aluminum tube to a "T" fitting. One outlet of the "T" goes to a primer solenoid which is connected by 1/8" aluminum tube to a bulkhead fitting high on the firewall and the other outlet is connected by a 3/8" aluminum tube to a bulkheaad fitting high up on the firewall. On the forward side of the firewall the primer path is connected to the primer ports on cylinders 1,2 & 4 through 1/8" aluminum, and copper tubing with full circle strain relief loops and "T"s and silver soldered primer fittings. The main fuel path is through a hose to the engine driven mechanical pump and from there to the carburetor input. Those are the only two fuel pumps in the system and they are in series and they both serve what ever tank in selected. After takeoff the electric fuel bump is turned off and all fuel pumping is done by the engine driven mechanical pump. No pumps are added for the tip tanks. In short race configuration I remove the tip tanks because they go between the wing tip and the stock tips and add 18" to the wing span and reduce the maximum speed by 3 knots. The only special precaution with tip tanks is to not select one for takeoff because if they are not full the fuel will move to the rear of the tip and if the fuel quantity is low enough and you climb out at a high angle it will leave the pickup tube sucking air.
My system works perfectly, never a problem in 9 calendar years and 900+ operating hours.
Bob Axsom
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rmartingt
Well Known Member
Thanks for posting your pictures of the process... I'm looking to do the same thing (since I don't have another $4k to drop, but do have time to spare), and your pictures are much clearer than the other ones I've found.
Gravity feed from tip tanks
Thanks guys. I'll be running a separate 3/8 tube aft of the spar to a common junction under my seat (two tip tanks and a removeable internal tank with dry-break connector), then that goes forward to the AUX position on my fuel selector. I want to be able to select AUX at top of climb so I have a way to confirm I have exhausted all the AUX fuel before I tap into the mains. Both the electric and mechanical fuel pump are in the loop with AUX selected, but I don't want to rely on the fuel pump pulling fuel through. When the tip tank levels get low, fuel will slosh away from the pickup finger screens and cause bubbles that will lead to pump cavitation. Hence, when it isn't sloshing, I am hoping the fuel vent will pressurise the tanks just enough to push the last of the fuel over the 2" rise of the first wing rib. I may yet drill through the ribs out at the tip where the compromise is least of a problem and then route the pipe into the lightening holes as it comes down the wing.
Some very interesting points in this forum about tip tanks. All good food for thought. I had considered most of it all before, but it will be interesting to test fly with the extra weight outboard. Anyway, its for very long transits, which will be rare, so I'll be sure only to fill the tips when I have a long smooth runway to avoid stress on the wings until the tip fuel is burned off.
Cheers guys.
Thanks guys. I'll be running a separate 3/8 tube aft of the spar to a common junction under my seat (two tip tanks and a removeable internal tank with dry-break connector), then that goes forward to the AUX position on my fuel selector. I want to be able to select AUX at top of climb so I have a way to confirm I have exhausted all the AUX fuel before I tap into the mains. Both the electric and mechanical fuel pump are in the loop with AUX selected, but I don't want to rely on the fuel pump pulling fuel through. When the tip tank levels get low, fuel will slosh away from the pickup finger screens and cause bubbles that will lead to pump cavitation. Hence, when it isn't sloshing, I am hoping the fuel vent will pressurise the tanks just enough to push the last of the fuel over the 2" rise of the first wing rib. I may yet drill through the ribs out at the tip where the compromise is least of a problem and then route the pipe into the lightening holes as it comes down the wing.
Some very interesting points in this forum about tip tanks. All good food for thought. I had considered most of it all before, but it will be interesting to test fly with the extra weight outboard. Anyway, its for very long transits, which will be rare, so I'll be sure only to fill the tips when I have a long smooth runway to avoid stress on the wings until the tip fuel is burned off.
Cheers guys.
Long range tip tanks
G'day all,
Well it's taken quite a while to get back to my tip tanks, but I am pleased to say the port tip tank is just about finished and weighs 12lbs (5.45kg) empty with a capacity of 8.65 US GAL (32.9L). The construction method was to line the existing epoxy tip with another layer of glass and Vinyl Ester resin, with a VE resin fibreglass wall, carbon fibre reinforcement along the outer fillets and screw mounting strips, with a VE resin/Aerosil fillet inside followed up by a ProSeal fillet over that on all the internal seams. I cleco'd the tip back on the wing every time something was left to set to ensure the shape was matched.
I look forward to completing the other side, then I can begin to finish paint the wings!
I can't find where to 'manage attachments' to add an image, but I'm sure someone will pipe up
G'day all,
Well it's taken quite a while to get back to my tip tanks, but I am pleased to say the port tip tank is just about finished and weighs 12lbs (5.45kg) empty with a capacity of 8.65 US GAL (32.9L). The construction method was to line the existing epoxy tip with another layer of glass and Vinyl Ester resin, with a VE resin fibreglass wall, carbon fibre reinforcement along the outer fillets and screw mounting strips, with a VE resin/Aerosil fillet inside followed up by a ProSeal fillet over that on all the internal seams. I cleco'd the tip back on the wing every time something was left to set to ensure the shape was matched.
I look forward to completing the other side, then I can begin to finish paint the wings!
I can't find where to 'manage attachments' to add an image, but I'm sure someone will pipe up
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