Danny M2Z

G'day Jon. I just picked up a 30 year old OPS 30 Maxi. 30 cc, 2 stroke glow, Dell'Orto carb with internal pump from c/shaft bleed and caged needle rollers on both ends of the rod. It's long stroke gives it bags of low down torque, it idles at 1,800 on an 18"x8" and peaks at 7,600. Due to the needle roller rod and twin ball bearing shaft 5% max oil is advised with no nitromethane. I just had it on the test stand when a mate from the local club came by and he was very impressed. Not too noisy either, the original muffler had been replaced with a large Super Tigre canister muffler. He said that when he got out of his car, he thought that I was doing some lawn mowing. Apart from the fact that the carby diaphragm material must have been carefully selected (it still works fine) and the jets are sized for glow fuel it's a big torquey pussycat. Hand starts are a doddle. Mate asked where he could get one. So maybe a modern equivalent from Laser could be the go - similar size and specs. I know that the needle rollers are a pita to fit, but if the Italians could do it back in 1984 then why not? * Danny M *

Thanks E.D. That's the engine. I actually found an RCM&E 1984 review of this engine. Bags of low down torque due to the long stroke and reliable idle at 1,400. No wonder the scale people liked them. I suspect that with their racing pedigree, OPS would have specified the carburettor materials and jetting to suit 95% methanol and 5% oil. Interestingly; nitromethane additive is not advised. As for a petrol conversion, the head fins are probably optimised for the cooler running alcohol fuel so maybe a bit small for petrol use. Now I just have to decide on a suitable scale model to do it justice. I initially thought of a BE2e about 100" would be nice, but alas too many around so then I found my documentation and Wylam drawings of a Loening OL9. This is nice. The free flight version **LINK** apparently flew nicely with a Mills 1.3 diesel engine in 1957, I used a PAW 1.5cc diesel in an r/c version over 20 years ago. It hauled off the lake (Hume) with 4 x Futaba S133 servos and required throttling back to cruise. Sold to a cashed up property developer from Sydney. I wonder how big I would have to make one to suit the 30cc OPS? It's only got about 5.5 HP. Maybe an 18" 3 bladed prop should determine the size of the model ( It has to clear the float). The screw-jack retracting U/C is going to be interesting as the U/C compartment would have to be sealed from the rest of the model. The full size was equipped with a bilge pump. * Danny M * Edited By Danny M2Z on 30/11/2015 02:23:16

G'day. I went to a garage sale today and for a hundred bucks I picked up 7 model engines. Most of them were still on the test stands and have never seen a model. Included were a few OS LA's, a nice OS 40 FSR ringed and an SC 108 - but the one that intrigues me is an OPS 30 Maxi. It looks like a brute with the 18"x8" prop and an De'Orto pumped carby. The instruction sheet advise 5% oil as it has needle rollers on both ends of the con-rod. So has anybody used one of these and any advice? It looks a little large for Control Line use. * Danny M *     Edited By Danny M2Z on 28/11/2015 10:07:37 Edited By Danny M2Z on 28/11/2015 10:10:47

Posted by Josip Vrandecic -Mes on 25/11/2015 12:58:20: Hello Danny , thanks indee for Joe's Meredith Effect.... Cheers Jo G'day Josip. I am am glad that you enjoyed Stuart Sherlock's website, it is very educational. I met Stuart at an Aussie Nats and purchased some of his propellors, absolutely the best carbon fibre props that I ever found. Designed scientifically (Supercool is a nuclear scientist/physicist) and made from CNC moulds with the appropriate resins. They are very good. We should all be greatful that such a talented scientist loves aeromodelling and I am proud that he's an Aussie. The 'Meredith Effect' article was a relevation to myself also and caused a serious re-think on the importance of designing the internal cowling ducting properly. I suspected as such many years ago when I used to fly pylon racers. A pair of supplementary 'NASA Low Drag' cowl inlets were incorporated in a few models and ducted to just cool the rear part (exhaust) of the cylinder. I think that it may have worked as I never had a buggered (cooked blue) cylinder liner after that. A properly designed engine cooling system is well worth the effort, and sadly, leaving the cowling off is not the way to go unless you have a really crappy cowling - then fix it! * Danny M *

Which resin is is your fibreglass fuselage moulded with, polyester or epoxy? Use epoxy to glue to epoxy, polyester resin to glue to polyester. * Danny M *

G'day. Have a look here **LINK** and while you are on Joe's site, this is worth a good butcher's **LINK**. * Danny M *

G'day, When I was a a kid a decent .049 model brought much satisfaction. Jump a few years later and a .15 was an engine to be admired, I learnt to fly a KK Spectre with a FROG 2.49BB. I dreamt about an Ollie Mk III Then the horsepower race developed until the FAI limit of 10cc was hit. The FAI aerobatics aircraft of the day were smooth to fly and carried reliable electronics. Nowadays, unless one has a 50cc petrol powered hovering gyro-stabilised ARF with onboard video one is out of the loop. Do the users demand this or are the manufacturers pushing the big petrol powered models onto the public powered by their 'bigger is better' mantra? Who drives the market, the modellers or the trade who realise that most people are not aeromodellers any more but just model flyers? * Danny M *

G'day, All oils ain't good oils. So this is the good oil. Stihl Ultra is very good (it's pink). Klotz 2 stroke oils are also excellent (they are usually red). Any oil designed for racing 2 stroke motorbikes or snowmobiles is usually very good. If you buy the cheap stuff from the local discount place it might work in your lawn mower, but then it could be the fridge compressor PAG type that gets re-packaged as model engine oil (with a big mark-up). Who knows what it actually is? Actually, after looking at the Laser Engine thread, this might be an excellent question to ask Jon Harper as he has been experimenting with oil ratios in his engines. * Danny M *

Why does it have to be CNC cut? One of these **LINK** should do the job. I purchased mine for $2 at the $2 store here in Oz. Good for gaskets too! * Danny M *

G'day Peter, you may also wish to check out **LINK** and **LINK** .- Also **LINK** can produce a suitable input for these programs from a scan of your aerofoil section. * Danny M *

Posted by alan robertson 3 on 20/11/2015 12:54:50: Just wondering if anyone like me does not like hand launching (solo), I always find you are in a state of non control for a split second till you get your 2 hands back on the Tx I fly Free Flight models, so usually hand launch and the model is not in control from the moment that it's released. That's why accurate trimming is important. If I have an r/c model that will not fly 'hands off' I would find out why and fix it. Even my pylon racers stay where they are pointed - you should only touch the sticks to change the flightpath or power, deploy gear or flaps etc. If your models are properly trimmed then the momentary loss of control should be of little concern. Then you could always try VTOL, I just found a nice looking kit **LINK** - quite an interesting concept. * Danny M *

Daithi, I think that you are correct, but still worth a photo or two. It flies around above the lake also. It's interesting to see the water bombers, they often top-up locally, right in front of the lounge room windows. I saw a very large Sikorsky wokka-wokka fly over last week. * Danny M *

G'day. The bushfire season is here again. over 100° here tomorrow. I looked out the front door just in time to see this, so ran in and grabbed the camera. I think it was a practice water pick-up run. Lake Hume, NSW-Vic border, Australia. Still intend to visit the local airport and get some photo's of the Focke-Wulf 190. * Danny M * Edited By Danny M2Z on 18/11/2015 06:22:07