Civilianize an AH-6, possible (or even worth it)?

[Helicopterist]

"lads, will someone get hold of the AH-6 version and civilianise it ... over 600 shp on tap from the C-30 and six blades. 4,000 fpm rate of cimb. Absolutely staggering."

Considering this is the opinion of the esteemed DennisK I am indeed intrigued. But is it utopia? I could find no record of these going into civilian hands, and at the most one could just hope to get it on a permit to fly/experimental cat. And even so where would you get parts etc.?

Has anyone converted one? Or even ever flown it (apart from Dennis)? How is it? Does it outperform a sa342 (which would seem to have a comparable power to weight)?

A 600 shp hughes indeed sounds like a racecar but the sa342 has over 800 shp (even if derated), is more likely to get a certificate of airworthyness and you can (somewhat) find parts for it. Shouldn't it be a comparable performer?

[TwinHueyMan]

The one I'm wondering about is the Bell OH-58Ds the Army is soon going to be replacing. They have a C30, FADEC, and 5200lbs max gross... if that thing could be brought to 2500lbs empty pulling all the elctronic spy gear crap off, I bet it'd be quite the stump puller... and cheap!

[Freewheel]

I understand that the equivalent to the AH-6 has even more power, 800 odd, and a bit more cabin room. It's called the MD600. Not a hugely successful type in civvy world, but you never know.

The OH-58D appeared to me to be the ideal upgraded Jetranger. Dunno why it never happened on the civilian side. Might not have saved it for that much longer, but would surely have sold reasonably well with a blade fold kit (just like the 407's, which seems to be going quite well). Perhaps this is what Bell plans? Now there's a rumour!


For ex-military conversion, they're both going to be restricted category, maybe limited if you're prepared to do the work and operate with the restrictions. No hope of getting them into the standard category.

[500 Fan]

It's hard to know if this helicopter will feature on the civil register in the future. There are plenty of exotic ex-military helicopters on the N-register with various police forces. The Huey Cobra is in use with the forestry service as a spotter.

Check out the registration "N13SD". This an ex-Hughes 500P funded by the C.I.A. and flown by Air America back in Vietnam on a clandestine mission in 1972. It was one of only two built. It is a truly unique version of the 500 with a Y-configuration tail plane and a five-blade main rotor head. Granted it is a police helicopter, but may eventually fall into private ownership. So I would say the A/MH-6M may at some point be released for civilian use, but again probably to a police force first. Blackwater would, no doubt, like to get their hands on a few.

The F.B.I.'s Hostage Rescue Team operate N-reg MD530FFs with external personel transport "planks" similar to the MH-6J while the C.I.A. are currently operating a classified version of the MD500 refered to only as "a 5XX-type helicopter". The H-6M will probably be very busy with the 160th SOAR for the next few years anyway.

500 Fan.

[tbtstt]

I understand that the equivalent to the AH-6 has even more power, 800 odd, and a bit more cabin room. It's called the MD600. Not a hugely successful type in civvy world, but you never know.
The MD 600 is, effectively, a "stretch" version of the MD500, its also a NOTAR, so its quite a different animal to the A/MH-6.

The A/MH-6 is closer to a MD500, though what variant is open to discussion. The airframe is said to be based on a 530, but has the proportions of a 500D (i.e. the bubble canopy oppose to the pointed canopy of the 500E). The latest version of the A/MH-6 features a six bladed main rotor and the C30 powerplant - as was mentioned earlier in the thread - I would assume the main rotor is based on a scaled down version of the 900 head or lifted directly from the 600 and, as a consequence I'd assume the tail boom/tail rotor gear box is the extended version found on the MD530FF, but there isn't really much concrete information on the aircraft so I cannot say any of this with any degree of certainty.

In fact its difficult to say anyhting "for sure" with regards to the A/MH-6 as, given its uses, the aircraft remain shrouded in secrecy. I would imagine that, for this reason, converting one to a civil registration would be an impossibility; at least for some time until after the types retirement anyway. As 500 fan says above, I'd imagine law enforcement agencies would get priority on the adoption of the type long before civilian sale would be considered.

I'd love to see one up close though, as, to date, it truly represents the pinnacle of the MD500's development.

[RVDT]

Just do it yourself..................

Buy a later or modified 530 and dump the 600N head on it. It should already have the 600 MGB. Plus a few tweaks here and there and off you go. Make sure you stick "EXPERIMENTAL" on the side.

The question would have to be "why" of course. I have seen the AH-6 or whatever it was called, in AZ, back in 1997. Be a little careful though, if you stick your head back in the helicopter aerodynamics books, you might find it is not a good solution. Take the MD600N, and look at things like, solidity ratio, best L/D, parasite drag, etc etc, and you will find it doesn't really work very well. For example a 500C actually has a better useful load above 10,000' than a D/E model and has a higher power margin for the same reasons.

The 600N would have to be one of the worst helicopters I have ever flown. Can you spell "Edsel?"
Be a little careful what you wish for, Cheaper, Faster, Better - pick two. :rolleyes:

[Freewheel]

To expand slightly on RVDT's point,

The "C" with the C20, rather than the C18 engine will do more at very high altitude.

For a practical standpoint at regular altitudes, compare the H-V diagrams from the C, D-E and 600.

Compare the fuel burn rates of the C, D-E and 530F.

Consider how much extra stuff the -6M needs to carry and how much fuel it's likely to have, then how long it's likely to be able to carry it.

If you really, really want and can afford one after all that, go for it! I'm sure we'd like to see it for interest's sake.

[CGWRA]

My company mostly uses 500's for drill moves. We currently still fly D models because they are the better lifters than the E model. Also the visibility is better. I get the feeling their future in the company was somewhat at risk with the ****ty PMI blades. Thank god for MD stepping to the plate and banging out blades again. We already have a set on one of ours and I hear its a stump lifter now. I hope it rekindles their future. I would love to see how the 530F performes but considering the huge upgrade in the powerplant the gross weight doesnt really increase all that much. Hopefully someone on the boards has done some external work with the 530 and can let us know what it will lift at sealevel without wind.

I would love to see a photo of the newer M/AH-6 with the 6 rotor blades. They have had C-30's for awhile though I believe.

Correct me if I'm wrong but didnt they add the 5th blade for ground resonance issues?

[RVDT]

Freewheel,

The "C" with the C20, rather than the C18 engine will do more at very high altitude.

A "C" always had a C20 in it. With a C18 it was just a 500, the "C" being a commercial designation only.

A thing you have to keep in mind is that all of these models are flying around with basically the same blade as an "A" model 269, just more of them and varying lengths. It probably makes for economic sense rather than aerodynamic.

The unfortunate thing on the 600 is that the rotor by now is not very efficient with 6 blades.

Correct me if I'm wrong but didnt they add the 5th blade for ground resonance issues?

?????

As for the 530, when you put such a big engine in a little helicopter, it is at the response limits sometimes for the fuel system. i.e the engine may be asked to respond quickly at very low power, due to the low inertia of the rotor, and it may surge or stall. I have heard of more than one instance of this and people getting hurt badly.

Picture of the 6 blade MH6 here (http://www.deagel.com/library/Little-Bird_m02006112200184.aspx)

Looks like a lot of modification on the attach points and maybe even a carbon tailboom.

[CGWRA]

check this picture out

http://upload.wikimedia.org/wikipedia/commons/b/b8/OH-6_Cayuse.jpg

I think this might be one of the 6 bladed ones. I've never noticed that extension on the vertical stab before on an AH-6 nor have I noticed the huge stinger. That tail rotor looks like it has a way bigger diameter as well. They have had the 530F engine bay doors for awhile, but there is a chunk taken out of that one. Interesting how it also still has the "D" style tip caps on the horizontal stab instead of the twist style the "E" and "F" model 500's have.

I'm pretty sure the blades on the 269 (300) are thinner than the 369 (500) blades but I could be wrong.

[TwinHueyMan]

Check out that canted tail rotor!

Considering the Blackhawks those guys fly have a button that you can push to re-reference the OEI power limits while AEO, I bet the 500s are pretty rockin too! Unlimited budget must be nice!

[Freewheel]

RVDT,

I stand corrected, I've been thinking of the HS model as built by Kawasaki for this part of the world.

[Scissorlink]

We currently still fly D models because they are the better lifters than the E model. Also the visibility is better.D rocks, E is Crap


Supposedly a civilian 530F in NZ was going to have the 6 bladed head installed a few years back until it got destroyed

[tbtstt]

Couple of images, the A/MH-6M in its "MH" configuration:

http://img338.imageshack.us/img338/1710/297380242c05629cf49er3.jpg

And in the "AH" configuration:

http://img338.imageshack.us/img338/3122/image0133cntl0.jpg

The second picture is to small to really make out much detail, but the top picture gives a fairly good view of the head and an idea how much cant is on the (four bladed) tail rotor.

[CGWRA]

Man if you ripped all the military weight off that thing it would be one hell of a stump puller. I noticed they have the larger rocket pods now than one when they had the old ah-6. The tail rotor looks pretty crazy too. Damn I want to fly one!

[Hughes500]

cwgra

When did you get the new blades ( -525), i have been told they are not available yet ?
In fact a new e arrived in UK 4 weeks ago and it has htc pma blades that have been filled and faired to improve performance.
Would be interested to know what a D will lift with MD blades compared to having pma blades on as I will invest stright away. Mind you I am also told that the new pma blade with the new erosion strip on is very good

[Scissorlink]

Would be interested to know what a D will lift with MD blades compared to having pma blades150 pound loss with pma after using old MD blades, and a pig to Track always :)

SL

[CGWRA]

Hughes 500

I'm not totally sure if it has 525 blades now that you mention it. I just assumed they were since MD had announced the new blades and this set had been painted white where you check for the cracks for the torque event AD and the leading edge was modified as you said. They might very well have just been modified PMA blades like the E you received. Those blades made that particular 500 go from the worst lifter in our fleet to the best though.

[500e]

AH-6J Little Bird (http://www.globalsecurity.org/military/systems/aircraft/ah-6.htm)
:suspect:

[InducedDrag]

My friend owns the OH-6 test bed that was used in the design of the MH-6.

Here is what I found on the internet about it:

OH-6C’: One　 aircraft (65-12951) was modified with a 400 shp Allison 250-C20 engine, a five-bladed rotor, a four-bladed cruciform tail rotor and a T-tail, reaching a speed of 322km/h during a test flight from Edwards Air Force Base and pioneering features of the later MD500/520 and of the later special forces H-6 versions

It has all been reverted back to original and is now in standard cat. If you look close at it, there are various stiffeners that have been added around the fuselage. It also has cutouts on BOTH doors for weapons pods instead of just the left side.

It is a beautiful ship. I would upload pics but it does not look like you can.

I also am the proud owner of a oh-6. Mine flew 1200 hrs in Vietnam, suffered battle damage three times....One time by a RPG! It then served with the Nat Guard till 94. It is now registered in standard cat as well.

I must say....they are a fun ship. Would love the extra power though!!!

[nathan_m]

these guys have one for sale an old one thou - redhorseaviation.net (http://www.redhorseaviation.net/)

YouTube - Redhorse Aviation Overview (http://www.youtube.com/watch?v=o3xVHBh30w0&feature=related)

[Hughes500]

SL

Would agree with you there. I was hoping someone might have had MD's new -525 blades, to find out how good they are. I have filled and faired my pma blades on my D. She now goes 8 to 10 kts quicker than before, almost back to md blade speeds. FYI
65 psi 120 kts, 70 psi 128, 75 psi 132 kts 80 psi 138kts
Certainly seems to lift more but cant say how much

[Scissorlink]

Yip back filling PMA is the trick. I have seen some with abrasion strips sitting so much higher then the skin it looks as they tho they the strip was glued on as an after thought. Forgot to mention the speed thing.

SL

[Brilliant Stuff]

138kts :ooh: Goes to show how little I know about the MD range. That's shifting.

[160thfan]

I have looked into this a bit for a guy that wants a cool toy. The MRGB has different mounts. It has to be put into a jig that holds the 600 box and the frame in place while the mounts are fitted. There are only 2 jigs. They are not available to the public. I think it can be done by making a new jig. That leaves the tail rotor which is not like any other but could MAYBE be copied with the old whisper 4 blade. It takes a whole new tail boom not the 530FF type. Also the vertical fin is slightly different, along with fitting the bigger engine......
Anyway.....

[CGWRA]

Hmm its too bad you can't just buy the parts from MD individually. Kind of the same things as the UH1Y that thing would be one badass lifter.

Actually does anyone know if MD does the little bird stuff or did Boeing hang on to that contract too like the Apache when they sold MD.

[160thfan]

Boeing kept the Littlebird side of things. I think they were doing the MELB when the MD deal started.

[RVDT]

160th fan,

The "600" MGB can be retrofitted to the 520N and 530FF. Service bulletin. Just don't know how many have taken up on it.

[160thfan]

That's good to know, thanks for posting. Is there a civilian version of that tail rotor setup?

[500e]

Had 4 new blades delivered not filled and faired as standard.
As Hughes500 & Scissorlink say Speed & lift a down significantly to say the least!! (especially with the C18) , after a lot of emails with them & MDHI trying to get a definitive answer to questions, returned to manufacturer, to be replaced with series 2 blades we were told.:sad:.

To be continued on receipt of replacement blades

[Ian Corrigible]

So how much to convert a surplus ARH-70 prototype...? :E

I/C

[Scissorlink]

How come the the military get to use the round nose on the new little birds and we get stuck with the E version ??