Skymaster 1/5 F-86 Main Spar Length
11-12-2018, 03:30 AM
#1
Skymaster 1/5 F-86 Main Spar Length
Hi Guys.
I posted this question in my thread but feel it may have been lost in there so I will ask it here. I know there are a number of these flying and I was hoping someone could measure the length of the large main Carbon Fiber Spar.
Here are my dimensions:
Length = 25 3/8"
This leaves 8 3/16" sticking out each end of the fuse
Left wing spar socket depth = 8 1/2" deep
This means the spar is 5/16" too short on this side (or the stops have been installed in the wrong spot if 8 3/16" gets you to all the load bearing ribs)
Right wing spar socket depth = 9 1/2"
This means the spar is 1 5/16" short on this side (and possibly the left side is well if the stopper was installed in the wrong spot and 8 3/16" does not get you to all the load bearing ribs)
My concern is that the spar may not be long enough to engage all of the load bearing ribs. I had a jet in the past where the spar was too short and missing the engagement in the outer rib by 1/2" or so. Eventually that wing began to sag in flight and I was able to catch this and fix it before it failed completely. I also remember alerting a number of modelers about the spars being too short on the small Skymaster F-4. Skymaster sent out new spars to everyone.
Can you guys measure the spar on your please?
Joe Lewis can you tell from your broken wing how long the spar should be to engage all the load bearing ribs?
Thanks Guys!
I posted this question in my thread but feel it may have been lost in there so I will ask it here. I know there are a number of these flying and I was hoping someone could measure the length of the large main Carbon Fiber Spar.
Here are my dimensions:
Length = 25 3/8"
This leaves 8 3/16" sticking out each end of the fuse
Left wing spar socket depth = 8 1/2" deep
This means the spar is 5/16" too short on this side (or the stops have been installed in the wrong spot if 8 3/16" gets you to all the load bearing ribs)
Right wing spar socket depth = 9 1/2"
This means the spar is 1 5/16" short on this side (and possibly the left side is well if the stopper was installed in the wrong spot and 8 3/16" does not get you to all the load bearing ribs)
My concern is that the spar may not be long enough to engage all of the load bearing ribs. I had a jet in the past where the spar was too short and missing the engagement in the outer rib by 1/2" or so. Eventually that wing began to sag in flight and I was able to catch this and fix it before it failed completely. I also remember alerting a number of modelers about the spars being too short on the small Skymaster F-4. Skymaster sent out new spars to everyone.
Can you guys measure the spar on your please?
Joe Lewis can you tell from your broken wing how long the spar should be to engage all the load bearing ribs?
Thanks Guys!
11-12-2018, 09:14 AM
#2
Maj. Woody, I think you may have been given a short spar. I have the same model and the large carbon spar I have is 31 1/4 inches long.
The socket, on each wing, is 9 1/2 inches deep. I think that maybe SM did not put end stops into the socket as the assembly manual mentions to be sure to check that feature so the tube does not move.
What I did was mount a block on the socket in the fuselage and drill through the block and thru the fiberglass tube. Then when I install the solid carbon tube centered with the fuselage, I tighten a small screw
against the carbon rod to ;hold its position.
This block and screw are accessible in the gear well area.
Hope this helps out.
Rod
The socket, on each wing, is 9 1/2 inches deep. I think that maybe SM did not put end stops into the socket as the assembly manual mentions to be sure to check that feature so the tube does not move.
What I did was mount a block on the socket in the fuselage and drill through the block and thru the fiberglass tube. Then when I install the solid carbon tube centered with the fuselage, I tighten a small screw
against the carbon rod to ;hold its position.
This block and screw are accessible in the gear well area.
Hope this helps out.
Rod
11-14-2018, 07:14 PM
#7
Join Date: Jun 2006
Location: Gold Coast, Queensland, AUSTRALIA
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Dom,
My main carbon spar is also 31" long. But I must admit that I cannot say with certainty how far they should go into the wings. It seems to me that there are no stops in the wing tubes at aĺl. Perhaps John can let us have a scale drawing of the wing construction so that we can tell exactly where the ribs are.
Cheers,
JanR
My main carbon spar is also 31" long. But I must admit that I cannot say with certainty how far they should go into the wings. It seems to me that there are no stops in the wing tubes at aĺl. Perhaps John can let us have a scale drawing of the wing construction so that we can tell exactly where the ribs are.
Cheers,
JanR
