Is your Rebel a 1650lb gross airplane?
Posted: Wed Aug 12, 2015 12:15 pm
Is your Rebel a 1650lb gross airplane? Not sure?
While the wing is the primary area of concern, there are other areas that are involved with increasing the gross weight to 1650. The current assembly manual depicts a 1650 airplane. So, a configuration check with the current manual is a good way to ensure that your airframe is in compliance. You will almost certainly not see any part numbers on your completed aircraft of course but it will alert you to missing parts and their respective part numbers.
And since you don't have part numbers on your aircraft, what the manual won't help you with is determining if some of the parts on your aircraft are of the correct thickness.
Here's a checklist to help identify that your Rebel meets the requirements for 1650 gross weight:
Murphy Rebel 1650lb Gross Weight Requirements.
Wing
1. The thickness of the main lift strut attach fittings in the wings (P/N W0111 & W0110) should be .190” each.
2. Wing skin thickness (Top, Bottom & Leading Edge P/N’s W0126, W0127 & W0128) should all be .020”
3. Wing main spar thickness (P/N W0112) should be .063”
4. Wing rear spar thickness (P/N W0122) should be .040”
5. Top & bottom fuel tank skin thickness (P/N W0158) should be .032 or .040”
6. Leading edge root rib (P/N W0172) should be doubled.
7. Leading edge root rib stiffeners (P/N W0142 x 2) must be in place
8. Root rib attach bracket (P/N W0161) must be in place. This is the angle that ties the forward wing attach fittings into the leading edge root rib assembly.
9. An additional leading edge rib (W0120) should be in place 6” outboard of the root leading edge rib assembly.
10. Three main spar caps (made from W0138) should be present at the lift strut attach fittings; Aft side lower, aft side upper and forward side upper.
Other Areas
11.Thickness of wing strut attach fittings on fuselage (P/N FUS0002) should be .190”
12. Wing struts must be the extruded type, 5 ½” x 1 5/8” and not the lighter flattened tube style as used on the Ultralight version only
13. Check to see if the main landing gear drag strut has an inner sleeve doubler tube for its full length. (P/N LG0013-1) *Ultralight versions only have a short doubler at each end*
14. Lower slide tube (P/N LG0043) requires additional doublers.
15. Check to ensure that the main landing gear main strut is 1 ¼” thick. (P/N LG0044) Lighter versions are only 1”.
16. Check landing gear axle diameter and material type. (P/N varies depending on axle) Minimum diameter steel: .75” (P/N LG0105) or Minimum diameter aluminum: 1.25” (P/N LG0107)
17. Wheels and brakes must be Murphy, Matco or other cast or machined wheels and not of the lighter duty “spun” aluminum type.
18. Bungee landing gear assemblies must incorporate the channels for additional strength, but there is no requirement to fabric cover them….but please do because it looks so much nicer!
19. Powerplant should be minimum 100HP for satisfactory performance.
Cheers,
Nigel
While the wing is the primary area of concern, there are other areas that are involved with increasing the gross weight to 1650. The current assembly manual depicts a 1650 airplane. So, a configuration check with the current manual is a good way to ensure that your airframe is in compliance. You will almost certainly not see any part numbers on your completed aircraft of course but it will alert you to missing parts and their respective part numbers.
And since you don't have part numbers on your aircraft, what the manual won't help you with is determining if some of the parts on your aircraft are of the correct thickness.
Here's a checklist to help identify that your Rebel meets the requirements for 1650 gross weight:
Murphy Rebel 1650lb Gross Weight Requirements.
Wing
1. The thickness of the main lift strut attach fittings in the wings (P/N W0111 & W0110) should be .190” each.
2. Wing skin thickness (Top, Bottom & Leading Edge P/N’s W0126, W0127 & W0128) should all be .020”
3. Wing main spar thickness (P/N W0112) should be .063”
4. Wing rear spar thickness (P/N W0122) should be .040”
5. Top & bottom fuel tank skin thickness (P/N W0158) should be .032 or .040”
6. Leading edge root rib (P/N W0172) should be doubled.
7. Leading edge root rib stiffeners (P/N W0142 x 2) must be in place
8. Root rib attach bracket (P/N W0161) must be in place. This is the angle that ties the forward wing attach fittings into the leading edge root rib assembly.
9. An additional leading edge rib (W0120) should be in place 6” outboard of the root leading edge rib assembly.
10. Three main spar caps (made from W0138) should be present at the lift strut attach fittings; Aft side lower, aft side upper and forward side upper.
Other Areas
11.Thickness of wing strut attach fittings on fuselage (P/N FUS0002) should be .190”
12. Wing struts must be the extruded type, 5 ½” x 1 5/8” and not the lighter flattened tube style as used on the Ultralight version only
13. Check to see if the main landing gear drag strut has an inner sleeve doubler tube for its full length. (P/N LG0013-1) *Ultralight versions only have a short doubler at each end*
14. Lower slide tube (P/N LG0043) requires additional doublers.
15. Check to ensure that the main landing gear main strut is 1 ¼” thick. (P/N LG0044) Lighter versions are only 1”.
16. Check landing gear axle diameter and material type. (P/N varies depending on axle) Minimum diameter steel: .75” (P/N LG0105) or Minimum diameter aluminum: 1.25” (P/N LG0107)
17. Wheels and brakes must be Murphy, Matco or other cast or machined wheels and not of the lighter duty “spun” aluminum type.
18. Bungee landing gear assemblies must incorporate the channels for additional strength, but there is no requirement to fabric cover them….but please do because it looks so much nicer!
19. Powerplant should be minimum 100HP for satisfactory performance.
Cheers,
Nigel