SEFEGeorge Posted October 22, 2012 Share Posted October 22, 2012 One thing I've always been curious about but never asked. On the H models why is the left side skin above the wheel well not painted? Is is because of a heat problem with the APUs and using a different type of metal there? Quote Link to comment Share on other sites More sharing options...
GVS Posted October 23, 2012 Share Posted October 23, 2012 One thing I've always been curious about but never asked. On the H models why is the left side skin above the wheel well not painted? Is is because of a heat problem with the APUs and using a different type of metal there? You ain't the only guy who's wondered about this. Me being an A model troop and you haveing lots more experience in the 130 world, I don't feel so bad about not knowing the answer to this. Quote Link to comment Share on other sites More sharing options...
bonzo Posted October 23, 2012 Share Posted October 23, 2012 One thing I've always been curious about but never asked. On the H models why is the left side skin above the wheel well not painted? Is is because of a heat problem with the APUs and using a different type of metal there? All I know is that it gets very hot there and the material is either titanium or stainless steel. regular alu plating or the honeycomb would melt in these extreme temps. greets bonzo Quote Link to comment Share on other sites More sharing options...
DC10FE Posted October 23, 2012 Share Posted October 23, 2012 It's titanium. When we got the new H-models at Dyess, a Lockheed tech rep came with them. His name was George ???? and he spent the majority of his time in the NCO Club stag bar. He told me it was titanium. Oddly though, the commercial Hercs titanium panel is painted over. Perhaps because the APU is not certificated for inflight use? Don R. Quote Link to comment Share on other sites More sharing options...
SEFEGeorge Posted October 23, 2012 Author Share Posted October 23, 2012 You ain't the only guy who's wondered about this. Me being an A model troop and you haveing lots more experience in the 130 world, I don't feel so bad about not knowing the answer to this. All I know is that it gets very hot there and the material is either titanium or stainless steel. regular alu plating or the honeycomb would melt in these extreme temps. greets bonzo It's titanium. When we got the new H-models at Dyess, a Lockheed tech rep came with them. His name was George ???? and he spent the majority of his time in the NCO Club stag bar. He told me it was titanium. Oddly though, the commercial Hercs titanium panel is painted over. Perhaps because the APU is not certificated for inflight use? Don R. Yep, I have quite a bit of Herc experience but not on the 74 models and later. The 73 H models had GTCs. I figured it was titanium or SS because of heat but just wasn't sure. Don't the commercial Hercs have the same APU? If so it would seem like the APUs would be certified for inflight use. Quote Link to comment Share on other sites More sharing options...
Metalbasher Posted October 24, 2012 Share Posted October 24, 2012 Yep, I have quite a bit of Herc experience but not on the 74 models and later. The 73 H models had GTCs. I figured it was titanium or SS because of heat but just wasn't sure. Don't the commercial Hercs have the same APU? If so it would seem like the APUs would be certified for inflight use. It's titanium on the Hs and even the Js due to temps associated with APU. It can be painted, as it is on AFSOC acft (for the sake of tone down/camouflage) however the paint does stick to titanium well and the heat does take a toll on the paint, thus requiring reapplication. On a slick where tone down/camouflage is not a concern, it's just as easy to leave bare metal and not worry about it at all. Quote Link to comment Share on other sites More sharing options...
Lkuest Posted October 24, 2012 Share Posted October 24, 2012 I have seen a few slicks with a painted titanium panel, specifically Air Guard and AETC aircraft. Quote Link to comment Share on other sites More sharing options...
Railrunner130 Posted October 24, 2012 Share Posted October 24, 2012 We've gotten a few random airplanes back from PDM with that patch painted over. I haven't noticed if the paint peels, burns or anything like that. Quote Link to comment Share on other sites More sharing options...
DC10FE Posted October 24, 2012 Share Posted October 24, 2012 Don't the commercial Hercs have the same APU? If so it would seem like the APUs would be certified for inflight use. George, I have no idea why the APU's on commercial Hercs can't be operated in flight; they're the same. Of course my AOM reference is more than 20 years old -- it even has instructions for operating the Omega!. I'll check with a friend at Lockheed. Now I'm curious. Don R. Quote Link to comment Share on other sites More sharing options...
DC10FE Posted October 26, 2012 Share Posted October 26, 2012 OK, for anyone who is interested, a friend at Lockheed told me that when they converted from the GTC to the APU on the commercial Herc, engineering didn't make any effort to get FAA testing and certification for the inflight use of the APU at that time. He also said that today it would be cost prohibitive to have it done. Don R. Quote Link to comment Share on other sites More sharing options...
lilzac Posted March 18, 2013 Share Posted March 18, 2013 The APU is wired thru the touchdown relay switch. This only allows operation either on the ground or in flight with main gear down. Quote Link to comment Share on other sites More sharing options...
DC10FE Posted March 19, 2013 Share Posted March 19, 2013 The APU is wired thru the touchdown relay switch. This only allows operation either on the ground or in flight with main gear down. Todd, I've prefaced many a reply with this statement -- "It's been a very long time, but...." Well, it has, but I don't think the gear has to be down for the APU to operate in flight. I'm sure I've started it in cruise without slowing to lower the gear. I remember a note in the 130H-1 saying that the APU may not start or operate above 20,000 feet. Don R. Quote Link to comment Share on other sites More sharing options...
Ronc Posted March 19, 2013 Share Posted March 19, 2013 The APU is wired thru the touchdown relay switch. This only allows operation either on the ground or in flight with main gear down. lilzac, Gear position has no function regarding the APU operation other than the APU door position. On the ground the APU door opens to 35 degrees, in flight it's limited to 15 degrees. Don R you are absolutly correct, the APU should operate up to 20,000 feet. Ron Quote Link to comment Share on other sites More sharing options...
Ronc Posted March 19, 2013 Share Posted March 19, 2013 Sorry I meant to say weight on wheels not gear position. Ron Quote Link to comment Share on other sites More sharing options...
gmac Posted March 20, 2013 Share Posted March 20, 2013 My 2 cents - Gear does not have to be down for APU operation - touchdown switch on fwd strut (and relay in hog trough) allows full inlet door travel to 35 degrees with weight on wheels (strut compressed), limits door travel to 15 degrees with weight off wheels. Operation above 20,000 feet or 200 KIAS usually not possible due to inlet air density/flow. Quote Link to comment Share on other sites More sharing options...
NATOPS1 Posted March 20, 2013 Share Posted March 20, 2013 The APU WILL operate at 20,000 feet even upside down... You say WHAT! Marine aircraft 106 went inverted after the loss of one raft which hung up and (inflated) by the airflow which induced a rollover and "spin". The FE "hit" the APU control switch (with his head) as he departed his seat (wear your lap belt!) and it started and continued to operate until touchdown.... Quote Link to comment Share on other sites More sharing options...
Railrunner130 Posted March 22, 2013 Share Posted March 22, 2013 That's an item we check on FCFs. The APU must start in flight. I don't know the parameters, but I think it has to be at a certain airspeed. Quote Link to comment Share on other sites More sharing options...
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