Great video.... Long time EAA member, kit builder (two Van's RV's), engineer, airline pilot... Always admired the Questair Venture. Your saga is a bummer, but your approach and attitude is an inspiration.... I think it is solvable. FUEL LEAK... Jets have fuel leaks of their wet wings. They are specialty companies that send crews out to reseal fuel tanks on site. That is all they do. As you say there is no room in that slim Questair wing. However a talk with one of their expert tank seal Technicians might expose some secret techniques. I wonder if you can seal from thee outside? I fixed an RV tank leak at the fuel drain fitting. I removed the pant. Cleaned all around it. Put a fillet seal all around to fitting to skin interface outside the wing..... Touched the paint up. No more leak. Another idea, may or may not be practical but SLOSH COMPOUND tank sealant. Van's aircraft has been around RV's 50 years. In the early kits the aluminum, removable wet inboard wing leading edge fuel tanks were sealed with tank slosh, a white liquid. You pour it in and slosh it around. You turn the tank all around to coat the entire internal surface of tank, then dump excess out. It coated the entire tank internals. It lost favor and now for last 30 yrs Van's aircraft specifies the use of PRO SEAL (two part grey epoxy made as and for aerospace fuel tank sealant). You apply the sealant to mating surfaces before riveting the ribs, rear baffle and end close out ribs to wing skin. This is what you have most likely. Why did slosh method lose favor? If the surfaces were not prepped the slosh can peel from the large flat skin areas that were not sealing anything. Even if tank did not leak you had to deal with the slosh film floating around. The obvious problem you can't "slosh" a whole wing around like the RV's removable wing wo leading edge fuel tank... two people or even one can move the tank around off the wing, to distribute the slosh around. >> However It may practical to selectively inject some sealant and let it run along the bottom wing skin at rear spar and skin intersection. May be inject some slosh sealant to run along inboard rib to skin interface one at a time....
The comments sound like the product Tank-Cure. It is a two component epoxy, which is resistant against all fuels, also alcohol. Once I designed and welded a complex steel-plate tank. Pinholes in the welds were inevitable, the paint started to bubble there. I emptied the tank, let it vent-out and applied the product. Sloshed the tank and let the excess drip out. No single leak any more... not even a smell of fuel. This product is used in old rusty tanks with pinholes, mainly in oldtimers.
I met Questair Venture designer Jim Griswold's son Doug Griswold years ago when we both worked as engineers at Cessna. Doug was part of the team that developed the prototype and I believe he is responsible for the unique control system with the spring bungees and variable geared pitch control. Doug impressed me on the importance of low wetted area for efficient cruise performance. Indeed the Venture is a brilliant design from an aerodynamics standpoint. As noted from another comment the airfoil is not a laminar flow design but instead a blend of "traditional" NACA airfoils commonly found on other light aircraft. My interpretation of the complex gear arrangement was to keep the wing free of any breaks and gaps normally found where the gear folds up into the wings like the Glasair series. It might have gained a few knots in cruise speed with the collapsing/folding gear arrangement but oh the headaches it has caused. Too bad about the wing sealant issue I'm aware that early Van's aircraft are also now suffering from sealant problems after all these years. LOTS of aircraft out there with wet wings and no marks against the Venture in my mind, just an unfortunate characteristic of the sealant. Excellent but painful video. Looking forward to part 2.
The Questair uses the same airfoil as the Taylor craft and Vans aircraft (and many others). It is a great airfoil with a low pitch moment and predictable stall. The wing is 17% thick at the chord. The thin wing appearance is due to the aspect ratio and wing area, not laminar flow design.
Part of the problem is lack of control with flaps down, as one wing lower when on the wheels hauls the plane off to the side. This is not a rudder problem. A friend disabled the flaps on his. The funky rudder pedals and brakes don't help, either. Also, the aerodynamics are the same as the Malibu. The fixed gear version -- built that way -- was the Spirit, IIRC. I flew both prototypes and loved the handling but didn't explore the landing. There were also problems with the header tanks in the fuselage that the FAA required for certification, which was one goal of the plane.
Speed is nice but with a low wing design there is no guarantee of extricating yourself from a rollover crash... you put a rigid ring around the perimeter of the canopy looks to me like it would cut down those possibilities of getting out.
Designing an uncompromised, one-criterion aircraft has its drawbacks. Small wetted area means a small fuselage (= short) , = short wheelbase. Thin airfoil sections donot accomodate the tiniest wheels; brakes and axle's need also space. (= narrow wheelbase) Integrated fuel tanks have the same technical level, even higher level compared to pressure cabins: leaks are not allowed (also not in time). May be this is a step to far for a homebuilt. Use long plastic fuel bags like gliders use, I would suggest. Make these bags also exchangeable via the root ribs.. Beside technical challenges the pilot skills have to be at an other level, it is no Cessna. Only real aviators fly such a power-egg...
Great video.... Long time EAA member, kit builder (two Van's RV's), engineer, airline pilot... Always admired the Questair Venture. Your saga is a bummer, but your approach and attitude is an inspiration.... I think it is solvable. FUEL LEAK... Jets have fuel leaks of their wet wings. They are specialty companies that send crews out to reseal fuel tanks on site. That is all they do. As you say there is no room in that slim Questair wing. However a talk with one of their expert tank seal Technicians might expose some secret techniques. I wonder if you can seal from thee outside? I fixed an RV tank leak at the fuel drain fitting. I removed the pant. Cleaned all around it. Put a fillet seal all around to fitting to skin interface outside the wing..... Touched the paint up. No more leak.
Another idea, may or may not be practical but SLOSH COMPOUND tank sealant. Van's aircraft has been around RV's 50 years. In the early kits the aluminum, removable wet inboard wing leading edge fuel tanks were sealed with tank slosh, a white liquid. You pour it in and slosh it around. You turn the tank all around to coat the entire internal surface of tank, then dump excess out. It coated the entire tank internals. It lost favor and now for last 30 yrs Van's aircraft specifies the use of PRO SEAL (two part grey epoxy made as and for aerospace fuel tank sealant). You apply the sealant to mating surfaces before riveting the ribs, rear baffle and end close out ribs to wing skin. This is what you have most likely. Why did slosh method lose favor? If the surfaces were not prepped the slosh can peel from the large flat skin areas that were not sealing anything. Even if tank did not leak you had to deal with the slosh film floating around.
The obvious problem you can't "slosh" a whole wing around like the RV's removable wing wo leading edge fuel tank... two people or even one can move the tank around off the wing, to distribute the slosh around.
>> However It may practical to selectively inject some sealant and let it run along the bottom wing skin at rear spar and skin intersection. May be inject some slosh sealant to run along inboard rib to skin interface one at a time....
I think this is the best feedback I’ve ever had on one of my videos. Thanks for the advice, I will keep the community posted on my progress.
You are very generous and kind to offer such good advice. Good on you!
The comments sound like the product Tank-Cure. It is a two component epoxy, which is resistant against all fuels, also alcohol. Once I designed and welded a complex steel-plate tank. Pinholes in the welds were inevitable, the paint started to bubble there. I emptied the tank, let it vent-out and applied the product. Sloshed the tank and let the excess drip out. No single leak any more... not even a smell of fuel.
This product is used in old rusty tanks with pinholes, mainly in oldtimers.
I met Questair Venture designer Jim Griswold's son Doug Griswold years ago when we both worked as engineers at Cessna. Doug was part of the team that developed the prototype and I believe he is responsible for the unique control system with the spring bungees and variable geared pitch control. Doug impressed me on the importance of low wetted area for efficient cruise performance. Indeed the Venture is a brilliant design from an aerodynamics standpoint. As noted from another comment the airfoil is not a laminar flow design but instead a blend of "traditional" NACA airfoils commonly found on other light aircraft. My interpretation of the complex gear arrangement was to keep the wing free of any breaks and gaps normally found where the gear folds up into the wings like the Glasair series. It might have gained a few knots in cruise speed with the collapsing/folding gear arrangement but oh the headaches it has caused. Too bad about the wing sealant issue I'm aware that early Van's aircraft are also now suffering from sealant problems after all these years. LOTS of aircraft out there with wet wings and no marks against the Venture in my mind, just an unfortunate characteristic of the sealant. Excellent but painful video. Looking forward to part 2.
I am working on getting the Lancair IV turboprop back in the air and then refocusing on the Questair Venture
The Questair uses the same airfoil as the Taylor craft and Vans aircraft (and many others). It is a great airfoil with a low pitch moment and predictable stall. The wing is 17% thick at the chord. The thin wing appearance is due to the aspect ratio and wing area, not laminar flow design.
ok, that makes sense too, still means I can't access the tank to reseal it :(
Part of the problem is lack of control with flaps down, as one wing lower when on the wheels hauls the plane off to the side. This is not a rudder problem. A friend disabled the flaps on his. The funky rudder pedals and brakes don't help, either. Also, the aerodynamics are the same as the Malibu. The fixed gear version -- built that way -- was the Spirit, IIRC. I flew both prototypes and loved the handling but didn't explore the landing. There were also problems with the header tanks in the fuselage that the FAA required for certification, which was one goal of the plane.
thanks for the input.
Speed is nice but with a low wing design there is no guarantee of extricating yourself from a rollover crash... you put a rigid ring around the perimeter of the canopy looks to me like it would cut down those possibilities of getting out.
I am leaning towards the glasair design.
@@trueairspeed130The Glasair III also has limitations...
Designing an uncompromised, one-criterion aircraft has its drawbacks.
Small wetted area means a small fuselage (= short) , = short wheelbase.
Thin airfoil sections donot accomodate the tiniest wheels; brakes and axle's need also space. (= narrow wheelbase)
Integrated fuel tanks have the same technical level, even higher level compared to pressure cabins: leaks are not allowed (also not in time). May be this is a step to far for a homebuilt.
Use long plastic fuel bags like gliders use, I would suggest. Make these bags also exchangeable via the root ribs..
Beside technical challenges the pilot skills have to be at an other level, it is no Cessna.
Only real aviators fly such a power-egg...
Have you owned one?