Pilot RC Sbach 342 30cc

[Craig Spence]

Hi all,

I haven't posted on here for some time, I'm coming back into flying after a 3 year break and im shocked at the vast changes if im honest.

So to the topic, I will be treating myself in January to a pilot rc Sbach 342 30cc.

I have loads of questions and need help if you could.

1; The model weighs 4.85kg (as it comes). It requires x6 servos, what torque should I be looking at on them?, also does the throttle servo need to be of high quality?.

2; I am looking at LiFe battery's for the receiver, what mah will I require 3000+?

3; what battery should I have for the engine?, DLE 30cc.

4; Is a battery backer the way forward or dual batteries with dual harnesses suffice?.

5; Can you get 20x4wide wooden props? and would this be ok for DLE 30cc. Prop range (18x8, 18x10, 19x8 & 20x8.

6; I take that I will need a kill switch?.

Any help would be greatly appreciated.

Cheers,

Craig.

[Adrian Smith 1]

 

Welcome back Craig. I will try and answer some of your questions.

The generic manual that comes with the kit should give you guidelines on servo power as I recall. However, I would put 14-15kg on the rudder, 10-11 kg on the elevators and similar on the ailerons. Anymore would be overkill and any less may mean 3D flying might be a bit of a disappointment. As to throttle servo I would definitely recommended putting a good quality servo on there as if the DLE 30 is anything like my OS 33GT the throttle lever is spring loaded and a cheap will not do, particularly at tick over. If you can afford it look at some Hitec digitals which are quite reasonable.

Batteries are a personal choice but if you are using digital servos 3000 mah should be ok. As far as ignition goes it depends on the unit. Most work of a 4.8v although with my OS I can use 6v. 1500mah should be enough for a session.

I am biased about battery redundancy because I use PowerBox units which are excellent, but it depends on your budget. But some redundancy set up is required on the biggest petrol engines IMO.

I am a user of kill switches. For the sake of a tenner or so RCexel units are absolutely fine.

I am sure are other opinions on here, but I hope that helps.

Edited By Adrian Smith 1 on 12/11/2015 13:40:42

[Steve Hargreaves - Moderator]

All very interesting & relevant questions Craig....I've been pressing Mr Ashby to do an article on moving up from "Club" type models to larger models such as this as I think it would be an area of great interest to many....not least me....

Don't forget to think about suitable hinges, horns & linkages too....no idea what the kit ones are like but obviously larger models will put more stress on these items too.

Powerbox stuff is seemingly beyond reproach but I've often wondered what the power distribution units from HK are like...see here & here ....as these units appear to offer much of the functionality at a fraction of the cost....

[john stones 1 - Moderator]

Hello Craig

Ignition unit is 4.8v - 8.4v if I remember right so a 2cell Life will be o.k. on there.

John

[Gary Manuel]

Regarding the throttle servo selection:

As Adrian has said, DLE's (and most others I would guess) are supplied with a spring loaded throttle lever. This isto make them return to the tick-over position which is adjusted mechanically with a taper ended idle adjust screw. For RC purposes, we don't want this feature because it strains the servo and drains the battery. Pushing against the idle screw can also lead to the servo stalling.

What I do is unclip / remove the spring from the throttle lever and also completely remove the idle speed screw. This allows the servo to move all the way from full throttle to zero (engine cut) position and back, with no spring pressure. A standard servo can then be used.

[Engine Doctor]

Posted by Gary Manuel on 12/11/2015 16:43:26:

Regarding the throttle servo selection:

What I do is unclip / remove the spring from the throttle lever and also completely remove the idle speed screw. This allows the servo to move all the way from full throttle to zero (engine cut) position and back, with no spring pressure. A standard servo can then be used.

Hi Gary . The return spring fitted on walbro and similar type carbs is there for another reason beside closing the throttle. By all means remove the stop screw or unscrew it so that the engine can be killed on the throttle but leave the spring on and attached. The spring will not put undue strain on even a humble 148 servo . The spring alsovprevents the spindle from chattering and wearing the carb body. It's also a reliable failsafe. Should the throttle linkage become detached

[Adrian Smith 1]

I have learnt something from ED about what the spring on the throttle is for. I have heard before that folks remove the spring for the reason given, but my view is the spring is there for a good reason and best not removed. I think DLE have a walbro type carby and it's not too dissimilar to the actual walbro carby so I think they know best how to it should correctly function.

[Former Member]

[This posting has been removed]

[Craig Spence]

Hi all,

Well thanks very much for the warm welcome back and especially all the quality information.

After doing some more research I found out that the minimal recommendation for the servos is 180oz/cm which equates to a 13kg torque servo. I decided on this Savox SA-1256TG High Torque core less Digital servo @ £50.99.

What torque would I require for the throttle?, shouldn't be much surely?.

Decided on x2 3000mah LiFe batteries with a powerbox sensor switch- does the switch just work off of the one battery then switch to the other if a problem occurs?, or runs on both?, in the latter case should I chose two lower mah batteries to combine to higher all up mah??. Also, is LiFe the same as LiFePo?.

The ignition battery, would a 1500mah last all day or just a flight?.

The hinges are pre installed although not sure if glued, they look pretty good and heavy duty. Good pack that comes with it from the looks of the manual.

I'm undecided whether I should upgrade TX to a Spektrum DX7 or DX9. The DX7 looks the part and it seems Spektrum have upgraded all their gear.

I'm still research kill switches.

Thanks for feedback in advance,

Cheers all.

[Adrian Smith 1]

My 1500 mah ignition battery lasts at least 4 x 8 minute flights and doesn't need much of a charge for the next session so that's plenty enough life.

[Craig Spence]

Thanks Adrian, can you recommend a good kill switch?, I've read up on some mentioned and they say you need to cap them?, as they can cause minor issues?.

I have found APC do some larger props with wide sizes 20x6 wide from memory, just wondering if they drill out well?.

On my 70 Sbach I run a 15x4 wide prop and it's fantastic. Any experience with these larger props?, I'd prefer a wooden one but don't seem to do wide sizes.

Cheers,

Craig.

[Adrian Smith 1]

Hi Craig, Just Engines do an Opto kill switch I think, APC props drill out just fine. Better with a drill press if you have one or just a plain old reamer. As far as props go (with OS anyway) on engines over 30cc they recommend wooden props.

[Mike Bell]

Hi Craig

I have a 30cc MX2 using a DLE 30cc. I run an 18x8 Menz wooden prop which is an excellent match and I use the RcExcel ignition kill switch. Unless you have a very noise insensitive site you need to junk the muffler immediately, the noise it make offends me never mind the neighbours. I run "standard" digital servos all round (Hitec HS5625MG) with no problem. Ignition batt is a 2s Lipo 2200maH and rx runs on a 6v 2000mah NiMH. Dual batteries and Powerbox systems make sense for 50cc and up but are arguably overkill for smaller. No harm in fitting this stuff if it makes you feel better but I would spend that money on a decent silencer. FYI I went for the Weston 30cc canister and a custom made header.

Mike

[Craig Spence]

Adrian,

Thanks for that I'll have a look on just engines, I'll also do a bit more research on the prop front.

Cheers.

[Craig Spence]

Hi Mike,

18x8 prop is the running in prop as well isn't it?, that would be handy. From past experience though the difference with a lower pitch wide prop is great, I'd like to see if I can get anything.

I'll have a butchers at that kill switch as. As for noise?, I'm not sure and I'll have to ask, the new club I'm joining is by the M25 and a gun club!, houses arnt that close so I imagine I may be ok.

Having said that though, I do like the Pitts mufflers.

Do you get much time of your engine battery?, few flights or more?.

I'll have a look at Weston as well, thanks very much for the help. Much appreciated from all.

Cheers.

[Former Member]

[This posting has been removed]

[Mike Bell]

The 18x8 is fine for running in as well as general flying. I usually only get around 4 flights in but there is always plenty left in the batteries.

Mike

[Bryan Burton]

Hi Craig, I agree with Steve J about the Savox SA-1256tg servos, you don't need 20Kg servos on a 30cc plane. If you do go ahead and get them check them for gear backlash, I purchased two for my 50cc Extra 330SC and returned them to CML as the backlash was very bad. No problem with CML, had my money back because they checked other SA-1256TG servos they had in stock and all were the same !

Bryan.

[Craig Spence]

Thanks very much for the replies lads. I'll have a look at different servo's.
I just thought as the recommendation is 13kg I should be around that mark.
It's all good if it saves a little cash, the props a wise one as well.

Cheers again.

[Rich too]

You should be able to get decent Hitech for less than £30 each (it may raise a few eyebrows but my YAK will have HK sourced servos costing less than £10 ea - HXT 10kg).). My 30cc DLE powered YAK will have dual batteries and switches (for rc and ign), and a tech aero kill switch. for running in I'm using a Xoar 18 x 8 beech prop - I'm importing from US as they come pre-drilled for the multi bolt hub! I haven't found one in UK...

 

 

Edited By Rich2 on 15/11/2015 20:24:15

[Craig Spence]

Hi Rich2,

I've found hitec HS5585 mh digi coreless. They seem good for torque at 14kg, cost £40.47.

I'll keep looking, but happy with these, as said previously the minimum requirement States 13kg and I intend to stick to it.

Thanks very much for the help, gonna look at props again now.

[simon burch]

Craig,

I fly my jet at the club you mentioned, so within reason I don't think you will have a problem with your model. I've just started flying petrol and I have one of those pepper pot inserts in the standard DLE 30 exhaust and I was really surprised how quiet it was in the air. Unfortunately this only lasted 5 flights and an awkward dead stick wiped out the outlet on the exhaust. No idea why it cut.....was keeping it high and close, but the first time I got a bit low it cut in the worst possible place.

Not flown it since as I'm trying to source a new undercarriage.

With regards to servos, I would have something meaty on the rudder, but anything over 10kg on the other surfaces should suffice (unless you only have 1 servo on the elevator). One good thing about buying slightly over spec'd servos is that they could be transferred to something bigger if you upgrade.

Simon

[Craig Spence]

Hi Simon,

Thanks for the info, I think I'll keep on looking, it would be great to get a servo in the spec I want for £30 as it would free up some more cash. The ones I'm happy with at present are £40-£50.

Do you like the club?, I've been there once for a look around about 4 years ago. It looks a really good patch and well looked after.

That's a shame about the dead stick, I just repaired the under carriage on 70 class Sbach, it's hard to reinforce such a light airframe without affecting the weight. I ended up layering 4 bits of 1/8" ply drilling through them and attaching the undercarriage, then slid it in glued!, I think the undercarriage would snap before this now lol.

I got mine from carbon copy UK, and many others, there very good.

Thanks again.

[john stones 1 - Moderator]

Hi Tec 5645 mg are 12kg at 6 volt, used them on numerous models, good price and good servo.

John

[Adrian Smith 1]

I agree with John. I use then extensively and they are great servo at a reasonable price.