KR> New wing skin idea
Hi Sid I hear you but I have not done my final calcs yet, I might not make the tanks the full span between the spars but I would like to keep them full span for the stiffness it will give the wing being bonded to both the top and bottom skins. Regards Dene Collett Avlec Projects cc Builders of award winning aircraft tel:27419560048 cell: 27845805003 Port Elizabeth South Africa -Original Message- I have since installed smaller aluminum tanks. Think it through on the full length dimension for wing tanks. Sid Wood Tri-gear KR-2 N6242 Mechanicsville, MD, USA --- >
KR> New wing skin idea
At 01:41 PM 2/14/2014, you wrote: >I might not make the >tanks the full span between the spars but I would like to keep them full >span for the stiffness it will give the wing being bonded to both the top >and bottom skins. >Dene Collett + A long slender tank from root to tip, located immediately behind the forward spar helps to keep the CG shift to a minimum from full to empty on fuel. My tanks are just 10 inches front to rear behind the spar, full length of the outer wing panel and hold 12.5 gallon per wing. The CG shifts forward 1 inch from 25 gallon to empty. My tanks, while not connected from spar to spar, still add torsional stiffness to the wing, which, when built to plans, is already stiff enough. Larry Flesner
KR> New wing skin idea
Dene; Make sure that the airloads don't travel through the full-span box structure of the tanks, rather than through the box structure of the spars. Probably would delaminate from the skins over time. Thermal loads also concern me. Wood, aluminum, and fibreglass expand differentially with heating. Peter I hear you but I have not done my final calcs yet, I might not make thetanks the full span between the spars but I would like to keep them fullspan for the stiffness it will give the wing being bonded to both the topand bottom skins.
KR> New wing skin idea
Hi Wayne I appreciate your good advice and wisdom, however, I have experience with polystyrene foam in a KR wing being dissolved in flight and it is not good for the heart! I personally know a cozy builder that has had his tank spring a leak and had to replace a lot of foam in the wing, a very delicate operation. I build Whisper motor gliders for a living and their wings are 8m long each. The cores are cut on a CNC hotwire cutter in 1m segments with the washout already set. We join them with micro on a perfectly level table around the spar and glass over one side at a time. I have no worries about compromising the tortional strength of the wing as the tank will be bonded to the inside of the wing skins. This will offer much more ridgidity that the traditional methods. The bond between the different pieces is not a concern for me, if it is dome properly the bond will be at least as strong as if it was one piece. I plan on using 2mm or 3mm coremat as the core material Regards Dene Collett Avlec Projects cc Builders of award winning aircraft tel:27419560048 cell: 27845805003 Port Elizabeth South Africa -Original Message- From: KRnet [mailto:krnet-bounces at list.krnet.org] On Behalf Of Wayne Tokarz Sent: 14 February, 2014 5:58 PM To: 'KRnet' Subject: Re: KR> New wing skin idea I think you will be compromising the torsional rigidity of the wings with three pieces and relying on a bonded joint, ( I could be wrong here
KR> New wing skin idea
I built in wing tanks per the Diehl plans between the forward and aft spars, and from the WAF out to the first wing rib. Turned out to be 10.8 gallons per side. That 21.6 gallons would provide over 6 hours endurance plus reserve. Way longer than I care to sit in my tiny cockpit for one flight. I have since installed smaller aluminum tanks. Think it through on the full length dimension for wing tanks. Sid Wood Tri-gear KR-2 N6242 Mechanicsville, MD, USA --- > > Hi guys > It is my plan to put full length wing tanks inside my wings between the > spars ... > Dene Collett >
KR> New wing skin idea
Just remembered this one, did it years ago on a special project. Use any core you wish for front and back half of wing, and last a foam in the center area. Cover the spars with a releasable covering, (please don't laugh, but duct tape works really well for this!), lay up the whole wing as per normal. Cut the leading edge and slice the trailing edge, remove only the top or bottom half. Do your backside layups on the two skins and bond it all together. This is just the basic idea, I'm very sure you are more than capable working out the details, ( gas cap, lines, baffles, etc.). Just my humble two cents worth. Wayne -Original Message- From: KRnet [mailto:krnet-bounces at list.krnet.org] On Behalf Of Dene Sent: February-13-14 10:48 PM To: 'KRnet' Subject: KR> New wing skin idea Hi guys It is my plan to put full length wing tanks inside my wings between the spars but because it is common practice here to use polystyrene for a core and we all know what happens to poly foam when it even smells fuel, I have been trying to come up with a way to get rid of foam all together without having to produce a set of molds. I think I have a plan. The cores are hot-wired from foam blocks as usual but the core that we would normally use is discarded. The "female" form, which is cut with the washout already set in it laid out on a flat table. A thin sheet of mylar or similar is cut to the required dimensions and laid inside the foam form. Glass is then laid up on that with a core material. The skins can be made in three pieces: D box, centre section and trailing edge, all with "overlap" for bonding over the spars. All these can be bonded together over the spars. This method, if done carefully and accurately should produce a pretty fair wing skin that is strong, light and need very little fairing. Final washout can still be tweaked at final bonding. Any thoughts? Regards Dene Collett Avlec Projects cc Builders of award winning aircraft tel:27419560048 cell: 27845805003 Port Elizabeth South Africa ___ Search the KRnet Archives at http://tugantek.com/archmailv2-kr/search. To UNsubscribe from KRnet, send a message to KRnet-leave at list.krnet.org please see other KRnet info at http://www.krnet.org/info.html see http://list.krnet.org/mailman/listinfo/krnet_list.krnet.org to change options
KR> New wing skin idea
Hi guys It is my plan to put full length wing tanks inside my wings between the spars but because it is common practice here to use polystyrene for a core and we all know what happens to poly foam when it even smells fuel, I have been trying to come up with a way to get rid of foam all together without having to produce a set of molds. I think I have a plan. The cores are hot-wired from foam blocks as usual but the core that we would normally use is discarded. The "female" form, which is cut with the washout already set in it laid out on a flat table. A thin sheet of mylar or similar is cut to the required dimensions and laid inside the foam form. Glass is then laid up on that with a core material. The skins can be made in three pieces: D box, centre section and trailing edge, all with "overlap" for bonding over the spars. All these can be bonded together over the spars. This method, if done carefully and accurately should produce a pretty fair wing skin that is strong, light and need very little fairing. Final washout can still be tweaked at final bonding. Any thoughts? Regards Dene Collett Avlec Projects cc Builders of award winning aircraft tel:27419560048 cell: 27845805003 Port Elizabeth South Africa
