Jump to content

H-1 and H-2 Differences


hercmech14
 Share

Recommended Posts

Here's one difference:

They got rid of the wing isolation valves for the H2.

They didn't get the high pressure brakes until tail number 85-0035. Same with oil cooler augmentation, unless someone spend the cash on the TCTO. Digital fuel gages didn't come until 84-0206, unless someone spent the cash. Since active duty didn't/doesn't own any H2s (slicks), there's a chance someone actually did spend money to upgrade these.

Link to comment
Share on other sites

The Dyess H models were not hugely different than the E models except:

(H1 vs E)

APU vs GTC/ATM

-15 Engines vs -7 Engines

Structural wing differences INITIALLY: E models eventually all got the H model wings.

30/60 PPM flight deck AC pak vs 30 PPM Pak

Wing Divider Valve vs Isolation Valves

Bleed Air Regulators vs Bleed Air Valves

There we other minor differences I think like with the aux hyd pump cooler and a few other things but I think most were put into the E model system over the years.

Dan

Link to comment
Share on other sites

H2s have the better radar (AN/APN-241) and got rid of the old PPI. Instead, they have the Radar Display unit which can display your flightplan (inputted via SCNS) with weather and TCAS overlays. Really nice, just not good for being SKe wingman, but who ever really uses the PPI? ;) Also, they have the funky ADI and HSI, where you have to set the course and HDG bug down by the autopilot. Also, flushable toilet with urinals on the aft side of 245 (think plastic containers, don't drain outside). The H2s also have the emergency exits located in front of the prop arcs instead of behind. Also, yes, the wing isolation valves are gone with only the bleed air divider valve. If you don't know, the nice thing about the divider valve is that it allows the FE isolate part of the bleed air system while allowing pressurization with one unit unlike the E, H, H1 where you lose both packs if both isolation valves had to be closed.

Link to comment
Share on other sites

H2s have the better radar (AN/APN-241) and got rid of the old PPI. Instead, they have the Radar Display unit which can display your flightplan (inputted via SCNS) with weather and TCAS overlays. Really nice, just not good for being SKe wingman, but who ever really uses the PPI? ;) Also, they have the funky ADI and HSI, where you have to set the course and HDG bug down by the autopilot. Also, flushable toilet with urinals on the aft side of 245 (think plastic containers, don't drain outside). The H2s also have the emergency exits located in front of the prop arcs instead of behind. Also, yes, the wing isolation valves are gone with only the bleed air divider valve. If you don't know, the nice thing about the divider valve is that it allows the FE isolate part of the bleed air system while allowing pressurization with one unit unlike the E, H, H1 where you lose both packs if both isolation valves had to be closed.

Funky ADI and HSI! That's the FCS-105 flight director. ;-) And dude the 241 radar didn't come out until WAY after the H2s were delivered. What you're seeing are modded H2s with the 241. You must be young. :-)

Main differences are: H2s had the Bleed Air Divider Valve, FCS-105 Flight Director. There may have been some minor differences but those two were perhaps the main ones. I'm not sure about the flush toilets. They slowly made gradual changes to the H2 line all the way until the H3s were delivered.

When did the old dual INS first start showing up?

Now I forget when the 3000 psi brake pressures came about.

Edit: I will say I'm talking about H2's as delivered from Lockheed. Trying to compare differences now would be fruitless due to all the post delivery mods.

Link to comment
Share on other sites

The AF didn't have a lot of configuration control with the H2 line. They had good intentions though. Their plan was to get the best new options available on new aircraft and then retrofit the older aircraft. They were able to get new equipment, but the retrofit plan just didn't happen. The H3 came along not on purpose, but because there were just so many differences at that point they just couldn't call it an H2 anymore.

Link to comment
Share on other sites

Can anyone tell me the difference between the 74 Dyess Hercs and the ones the Reserves started getting in 78? Externally they look the same. Thanks in advance........Dave in western PA

I'll leave it to the engineers for the specifics, but they are very, very similar. I think the flight directors on the 78s may be different than the 74s. I really think they should be considered H1s and not H2s. It would be trivial for a Dyess crew to fly a Pittsburgh (former OK ANG) plane, but it takes a couple of hours of differences academics for an 85 or later H2 engineer to do it if they are unfamiliar.

Link to comment
Share on other sites

H-2 1/2 have a glass or semi glass cockpit. I never did get that straight. We couldn't fly on them as we couldn't H-3s. We had Jackson,MS H-2s ('79s IIRc) and then got new '88 H-2s. The newer H-2s we got had the newer seats, a flush toilet, HF antennas in the tail base, AC bus tie switch, laser ring gyro INS, and QD torq tube connects on the main gear (started with acft 88-1301). About every two years some things were different on the H-2s. The unit I was in has H-3s they got from Martinsbug,WV when they transitioned to C-5s.

Link to comment
Share on other sites

We had 84-204 and 205 at Dobbins and they had all the trick stuff such as the flush toilet, no long lines HF, 2 big side escape hatches and dual INS and batteries from the factory. I worked at Lockheed when the first ship with all the mods came down final assy....what a nightmare. I installed the first large set of side hatches as per the prod. engs written instructions. They didn't work. He told me to figure out how to rig them and he would put that in writing. It took me a day or two but I finally got it. Go figure ha ha. I think all the big -2 mods mentioned above started on ship serial 5000 in 1983 or 84. Can you confirm that With your trick book Bob? We had 6 ,81-2"s and 2, 84-2's at the DARB, a real can of worms sometimes... I loved it...but I don't miss it ! Bill

Link to comment
Share on other sites

How many H2.5's were built?

I had a list once upon a time but I can't find it.

I thought I remembered there were only 20.

12 originally at Louisville 91-1231 to 39 91-1651 to 53

8 at Mansfield 90-1791 to 1798

Maybe some at Youngstown?

Thanks

Bob

Bob, 92-3021-3024 at Youngstown are 2.5s
Link to comment
Share on other sites

Dan, you have one heck of a memory. I had a minor part in the delivery of the Dyess Hs. The command tried to get several subsystems improved or replaced. The only reason the acft. got -15 engines was there were no more -7 engines. Among other things, we wanted to replace the APN 59 the autopilot and move the top anti-collision lite to the backbone. ASD was the roadblock to the improvements sought. And in the middle of the run two acft. were diverted to the RCAF.

Link to comment
Share on other sites

Dan, you have one heck of a memory. I had a minor part in the delivery of the Dyess Hs. The command tried to get several subsystems improved or replaced. The only reason the acft. got -15 engines was there were no more -7 engines. Among other things, we wanted to replace the APN 59 the autopilot and move the top anti-collision lite to the backbone. ASD was the roadblock to the improvements sought. And in the middle of the run two acft. were diverted to the RCAF.

I was LRF starting in 1975 and we had the 73 Hs, basically pretty much E models with -15s; E model ACs, bleed system. The only other difference that I recall was the water removal system in the fuel tanks. I thought that the Dyess H models, 74s, were the 1st true H models, namely the ACs packs. It would appear that from the 73s on that the engines were all going to be -15s.

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

 Share

×
×
  • Create New...