SR3500 TIP TANK RETROFIT (PROPOSED)
Posted: Fri Feb 17, 2012 9:21 pm
I propose to do the following mods and am in the process of seeking MAMs
comments.
I would certainly like the extra 40 gals of fuel when flying in the
remote north.
MAM is now offering 120gal tanks using the first six bays but a retrofit
would be difficult as the spar wasn't prosealed and it requires a plate
next to the strut attachment to allow dry access. I think the following
should work and welcome comments. I have my wing already opened up for
the 3500 mods so a little extra work wouldn't be too bad at this stage.
SUBJECT: SR3500 TIP TANK RETROFIT (PROPOSED)
See attached schematic.
Location: 2nd and 3rd tip bays between stn 14 and stn 16.
This will allow installation of fiberglass tip and area to install
strobe system in last bay.
1. Remove leading edge extension
2. Remove and cutback top wing skin to outside edge (tip side) of 4th
end rib (stn 14).
Allow overlap sufficient for extra row of rivets. Wing skin will be
between Stn 14, W-173 rib and tank skin to allow easier sealing of
stringers from inside before tank skin installed.
3. Cut access hole in bottom wing skin between stn 13 and 14. (fuel tank
typical) This will allow access to fuel line fitting.
4. Leave end rib stn 17 in place.
5. Replace Stn 14/16 ribs with W-173
6. Replace Stn 15 rib with W-516
7. Replace main spar extension rivets with tank rivets from stn 14 to
stn 16.
Install plates with pro-seal over main spar lightening holes at stn 14
and stn 16
8. Replace rear spar rivets with tank rivets from stn 14 to stn 16.
9. Using drill attached to long tube drill appropriate hole through all
ribs so as to exit aft of main tank outlet between rear spar just aft of
last stringer. Pre-drilling Stn 14/15/16 will aid in guiding. Where
access available have a helper ensure proper drill location at rib
stations. Mark and use short drill where possible.
10. Install W-160 flange on stn 14 and Stn 16. (Stn 16 will be plugged
but will allow straight insertion of fuel tubing from tip through wing
if replacement required)
11. Install Nylon gussets in all assessable carry through ribs stn 7-13
12. Drill out two W-159 flanges to OD of Alum Fuel tubing.
13. Install W-159 Flanges on Stn 6 and Stn 1
Alum fuel tubing will be pro-sealed to these flanges mounted on main
tank ribs and tip fuel will be routed through main tank. Ensure Alum
fuel tubing extends 1" beyond stn 1 flange so as to allow rubber tubing
to be clamped over.
14. Install top tank skin from stn 14 to stn 17; use existing holes in
stringers, spars and stn 14 and stn 17 rib. Drill additional rivet holes
between existing holes along rib flanges at stn 14. (Caution do not
drill between flange and stringers) Drill stn 15, 16 flange with same
spacing as stn 14. Add an extra row of holes along wing skin overlap
with same spacing. Tank skin will be over wing skin and under leading
edge skin.
15. Remove and cutback bottom wing skin to outside edge (tip side) of
4th end rib (stn 14).
Allow overlap sufficient for extra row of rivets. Wing skin will be
between Stn 14, W-173 rib and tank skin to allow easier sealing of
stringers before tank skin installed.
16. Install bottom tank skin from stn 14 to stn 17; use existing holes
in stringers, spars and stn 14 and stn 17 rib. Drill additional rivet
holes between existing holes along rib flanges at 14. (Caution do not
drill between flange and stringers) Drill stn 15, 16 flange with same
spacing as stn 14. Add an extra row of holes along wing skin overlap
with same spacing. Tank skin will be over wing skin and under leading
edge skin.
17. Fabricate access holes on bottom tank skin
18. Fabricate flanges to go around top and bottom stringers where they
pass through stn 14 rib.
19. Install flush fuel cap in top skin outer fuel bay. Tip tanks will be
individually vented through inverted 'J' pipe in cap.
20. Install fuel probe in stn 16 rib.
21. Debur all holes, pro-seal and rivet ribs, bottom skin, flanges and
leading edge skin clecoing main skin to stn 14 rib.
22. Install top skin with leading edge on top and tank access covers to
bottom tank skin.
23. Insert Alum fuel tube through wing. Insert screen filter in stn 14,
W-160 and join to alum tubing with nylon nipple and rubber fuel hose
with clamps. Ensure alum tubing well pro-sealed at stn 6 and stn 1 W-159
flanges. Alum tube will protrude 1" at root to allow attachment of
rubber tubing. Insert plug in stn 16 flange.
24. Pressure test.
Questions:
1. Is this the best location, 2nd and 3rd outer bays?
Other options are last two or all three.
2. Is this an acceptable way to route the fuel?
3. Does the plumbing solution sound feasible?
4. Will gravity feed work from the tips
5. Is the current rivet spacing acceptable with 1/8" rivets?
Should I add an extra rivet between existing ones along the rib flanges
and main spar.
6. Thickness of tank skins .032 or .040?
--
Warren T. Montgomery
<monty@emirates.net.ae>
Dubai, United Arab Emirates
--
Warren T. Montgomery
<monty@emirates.net.ae>
Dubai, United Arab Emirates
-----------------------------------------------------------------
List archives located at: https://mail.dcsol.com/login
username "rebel" password "builder"
Unsubscribe: rebel-builders-unsubscribe@dcsol.com
List administrator: mike.davis@dcsol.com
-----------------------------------------------------------------
comments.
I would certainly like the extra 40 gals of fuel when flying in the
remote north.
MAM is now offering 120gal tanks using the first six bays but a retrofit
would be difficult as the spar wasn't prosealed and it requires a plate
next to the strut attachment to allow dry access. I think the following
should work and welcome comments. I have my wing already opened up for
the 3500 mods so a little extra work wouldn't be too bad at this stage.
SUBJECT: SR3500 TIP TANK RETROFIT (PROPOSED)
See attached schematic.
Location: 2nd and 3rd tip bays between stn 14 and stn 16.
This will allow installation of fiberglass tip and area to install
strobe system in last bay.
1. Remove leading edge extension
2. Remove and cutback top wing skin to outside edge (tip side) of 4th
end rib (stn 14).
Allow overlap sufficient for extra row of rivets. Wing skin will be
between Stn 14, W-173 rib and tank skin to allow easier sealing of
stringers from inside before tank skin installed.
3. Cut access hole in bottom wing skin between stn 13 and 14. (fuel tank
typical) This will allow access to fuel line fitting.
4. Leave end rib stn 17 in place.
5. Replace Stn 14/16 ribs with W-173
6. Replace Stn 15 rib with W-516
7. Replace main spar extension rivets with tank rivets from stn 14 to
stn 16.
Install plates with pro-seal over main spar lightening holes at stn 14
and stn 16
8. Replace rear spar rivets with tank rivets from stn 14 to stn 16.
9. Using drill attached to long tube drill appropriate hole through all
ribs so as to exit aft of main tank outlet between rear spar just aft of
last stringer. Pre-drilling Stn 14/15/16 will aid in guiding. Where
access available have a helper ensure proper drill location at rib
stations. Mark and use short drill where possible.
10. Install W-160 flange on stn 14 and Stn 16. (Stn 16 will be plugged
but will allow straight insertion of fuel tubing from tip through wing
if replacement required)
11. Install Nylon gussets in all assessable carry through ribs stn 7-13
12. Drill out two W-159 flanges to OD of Alum Fuel tubing.
13. Install W-159 Flanges on Stn 6 and Stn 1
Alum fuel tubing will be pro-sealed to these flanges mounted on main
tank ribs and tip fuel will be routed through main tank. Ensure Alum
fuel tubing extends 1" beyond stn 1 flange so as to allow rubber tubing
to be clamped over.
14. Install top tank skin from stn 14 to stn 17; use existing holes in
stringers, spars and stn 14 and stn 17 rib. Drill additional rivet holes
between existing holes along rib flanges at stn 14. (Caution do not
drill between flange and stringers) Drill stn 15, 16 flange with same
spacing as stn 14. Add an extra row of holes along wing skin overlap
with same spacing. Tank skin will be over wing skin and under leading
edge skin.
15. Remove and cutback bottom wing skin to outside edge (tip side) of
4th end rib (stn 14).
Allow overlap sufficient for extra row of rivets. Wing skin will be
between Stn 14, W-173 rib and tank skin to allow easier sealing of
stringers before tank skin installed.
16. Install bottom tank skin from stn 14 to stn 17; use existing holes
in stringers, spars and stn 14 and stn 17 rib. Drill additional rivet
holes between existing holes along rib flanges at 14. (Caution do not
drill between flange and stringers) Drill stn 15, 16 flange with same
spacing as stn 14. Add an extra row of holes along wing skin overlap
with same spacing. Tank skin will be over wing skin and under leading
edge skin.
17. Fabricate access holes on bottom tank skin
18. Fabricate flanges to go around top and bottom stringers where they
pass through stn 14 rib.
19. Install flush fuel cap in top skin outer fuel bay. Tip tanks will be
individually vented through inverted 'J' pipe in cap.
20. Install fuel probe in stn 16 rib.
21. Debur all holes, pro-seal and rivet ribs, bottom skin, flanges and
leading edge skin clecoing main skin to stn 14 rib.
22. Install top skin with leading edge on top and tank access covers to
bottom tank skin.
23. Insert Alum fuel tube through wing. Insert screen filter in stn 14,
W-160 and join to alum tubing with nylon nipple and rubber fuel hose
with clamps. Ensure alum tubing well pro-sealed at stn 6 and stn 1 W-159
flanges. Alum tube will protrude 1" at root to allow attachment of
rubber tubing. Insert plug in stn 16 flange.
24. Pressure test.
Questions:
1. Is this the best location, 2nd and 3rd outer bays?
Other options are last two or all three.
2. Is this an acceptable way to route the fuel?
3. Does the plumbing solution sound feasible?
4. Will gravity feed work from the tips
5. Is the current rivet spacing acceptable with 1/8" rivets?
Should I add an extra rivet between existing ones along the rib flanges
and main spar.
6. Thickness of tank skins .032 or .040?
--
Warren T. Montgomery
<monty@emirates.net.ae>
Dubai, United Arab Emirates
--
Warren T. Montgomery
<monty@emirates.net.ae>
Dubai, United Arab Emirates
-----------------------------------------------------------------
List archives located at: https://mail.dcsol.com/login
username "rebel" password "builder"
Unsubscribe: rebel-builders-unsubscribe@dcsol.com
List administrator: mike.davis@dcsol.com
-----------------------------------------------------------------