HPA LCT RPD

[EvilMonkee]

I have been considering replacing the internals of my RPD with an HPA system as quite simply I cannot get it to shoot how I like, and whilst I dislike HPA it kind of makes sense for a support weapon that is only used in themed games.  So, with that in mind, who stocks said items in the UK and what would I need to be looking at to get it working?  Any recommendation of a particular engine?  Bear in mind that the RPD gearbox is not a standard gearbox.

 

[Adolf Hamster]

a non-standard gearbox isn't so much of an issue. the majority of engines on the market are cylinder replacements that will drop into the space used by the original cylinder in the gun.

kits tend to come with trigger replacement units which will be specific to a standard gearbox type (generally a v2 or v3) which have a pair of microswitches- one for the selector and one for the safety.

however you can also get "universal" plug boards which will let you wire directly into the existing trigger contacts (although unless you wire up your own microswitch you'll lose select fire), for example this is how i wired up the mg42.

nozzle length will be another factor, there'll be a range of different options but if you can't get one that suits you might have to get a longer variant and have it machined down yourself.

take a look at high pressure airsoft, they have a range of different engines (although admittedly stock doesn't look so good these days).

i'd suggest going wolverine over the polarstar jack/F1 offerings- those 2 are open bolt designs and not good for accuracy. the f2 is a great engine but overkill for a support gun role (unless you're factoring in that you might want to switch to a different gun/role in the long run)

 

[EvilMonkee]

Thanks.  

 

[SeniorSpaz87]

a non-standard gearbox isn't so much of an issue. the majority of engines on the market are cylinder replacements that will drop into the space used by the original cylinder in the gun.

kits tend to come with trigger replacement units which will be specific to a standard gearbox type (generally a v2 or v3) which have a pair of microswitches- one for the selector and one for the safety.

however you can also get "universal" plug boards which will let you wire directly into the existing trigger contacts (although unless you wire up your own microswitch you'll lose select fire), for example this is how i wired up the mg42.

nozzle length will be another factor, there'll be a range of different options but if you can't get one that suits you might have to get a longer variant and have it machined down yourself.

take a look at high pressure airsoft, they have a range of different engines (although admittedly stock doesn't look so good these days).

i'd suggest going wolverine over the polarstar jack/F1 offerings- those 2 are open bolt designs and not good for accuracy. the f2 is a great engine but overkill for a support gun role (unless you're factoring in that you might want to switch to a different gun/role in the long run)

Most of the second half I disagree with to some extent - F2 is excellent for support platforms, and has preformed in the role better than my Wolverine engines which shine in DMR/semi auto or quiet builds. I do agree with the Jack/F1 though - only reason I own a Jack is that its literally the only engine that will fit in a TM MP7. His main issue is that the RPD appears to have an offset nozzle. While the cylinder replacement takes care of the fit, the nozzle is going to be a big problem and either require a new gearbox design (like I had to do for my STAR L86), or youll likely be forced to use the Wolverine Hydra. Its a somewhat subpar engine IMO, but its the only one that really supports a wide range of offset nozzles. 

 

[Adolf Hamster]

Most of the second half I disagree with to some extent - F2 is excellent for support platforms, and has preformed in the role better than my Wolverine engines which shine in DMR/semi auto or quiet builds. I do agree with the Jack/F1 though - only reason I own a Jack is that its literally the only engine that will fit in a TM MP7. His main issue is that the RPD appears to have an offset nozzle. While the cylinder replacement takes care of the fit, the nozzle is going to be a big problem and either require a new gearbox design (like I had to do for my STAR L86), or youll likely be forced to use the Wolverine Hydra. Its a somewhat subpar engine IMO, but its the only one that really supports a wide range of offset nozzles. 

i don't deny the f2 is an excellent engine, but figured it was a bit too much adjustability for the role.

the offset nozzle does make a difference, done derped hard not looking it up...... (imma pretend i didn't get the rpd and rpk mixed up.....)

you can get offset nozzle configs for the f2, although a narrower range of lengths.

 

[EvilMonkee]

I think the best course of action is to take it to HP Airsoft and see what they can do with it, its not a long way from me

 

[SeniorSpaz87]

i don't deny the f2 is an excellent engine, but figured it was a bit too much adjustability for the role.

the offset nozzle does make a difference, done derped hard not looking it up...... (imma pretend i didn't get the rpd and rpk mixed up.....)

you can get offset nozzle configs for the f2, although a narrower range of lengths.

Yes, there are offset F2 nozzles though they are for specific guns, so its got to line up with an existing cylinder head. 

 

[Adolf Hamster]

Yes, there are offset F2 nozzles though they are for specific guns, so its got to line up with an existing cylinder head. 

yeah figured that'd be the issue, afaik p* will do a custom one although not sure if that applies to the offset variants, and regardless not a cheap solution.

 

[EvilMonkee]

So Wolverine Hydra the only solution?

 

[SeniorSpaz87]

yeah figured that'd be the issue, afaik p* will do a custom one although not sure if that applies to the offset variants, and regardless not a cheap solution.

Yea myself and my local tech asked about custom nozzles and the number we got, well, was a bit much. And this is coming from me - I have several guns in the 4 digit range and some even approaching 2 grand. Im not gonna say that the Hydra is the *only* option - I would message P*, Amped Airsoft, and Airsoft Junkiez (the latter two are two of the biggest custom HPA builders in the US and do this kind of stuff regularly) alongside any big HPA custom shops in the UK, and see if any existing nozzles out there will fit another engine and the RPD setup. The Hydra will work fine for you if you do have to go that route, its just not as good as say a F2 or Reaper. Also I despise the simple Wolverine FCUs - to the point that buying bluetooth boards is almost a necessity for me now for any Wolverine guns. You can certainly make due with the little dials, but nothing compares to having an actual screen to read off numbers. 

 

[EvilMonkee]

I have zero clue who the big custom HPA shops are in the UK...can you elaborate?  Thanks

 

[Adolf Hamster]

Yea myself and my local tech asked about custom nozzles and the number we got, well, was a bit much. And this is coming from me - I have several guns in the 4 digit range and some even approaching 2 grand. Im not gonna say that the Hydra is the *only* option - I would message P*, Amped Airsoft, and Airsoft Junkiez (the latter two are two of the biggest custom HPA builders in the US and do this kind of stuff regularly) alongside any big HPA custom shops in the UK, and see if any existing nozzles out there will fit another engine and the RPD setup. The Hydra will work fine for you if you do have to go that route, its just not as good as say a F2 or Reaper. Also I despise the simple Wolverine FCUs - to the point that buying bluetooth boards is almost a necessity for me now for any Wolverine guns. You can certainly make due with the little dials, but nothing compares to having an actual screen to read off numbers. 

if the offset is the same and it's just length is the issue, then as long as there's a longer nozzle available it'd be feasible to trim it down if you know someone with the right equipment.

i did it for the '42, trimmed down an sr25 nozzle to the right length, although granted much easier with a centred nozzle.

I have zero clue who the big custom HPA shops are in the UK...can you elaborate?  Thanks

highpressureairsoft is the biggest i'm aware of that's uk based, there's the likes of powair6 but they're in france.

as we're talking about you can contact polarstar directly although it'd be very pricey.

 

[Druid799]

whilst I dislike HPA it kind of makes sense for a support weapon that is only used in themed games. 

Funnily enough I’m exactly the same as you I’m definitely not a fan of HPA(the air pipe coming out of the grip would REALLY get on my tit !) but I can see it’s the perfect choice to run a static weapon , like a support gun ! ?