Maninder

By "perfectly tuned" I meant a tuned system which delivers a very large gain at one frequency (RPM) but the gain drops off rapidly away from that single RPM. A less than perfectly tuned system will deliver lower gain at the centre RPM but the gain spans over a broader range producing a wide power band.

Is that not why you would never go for a perfectly tuned setup but one that is tuned enough to deliver a power increase and lower noise but off-tune enough to provide a usable spread of power, same as any antanae design?

MVVS knew how to design good tuned pipes. I have two of these amongst my collection of engines. Although designed for their 26 IFS Petrol engne, they work equally well on any 20-30cc petrol 20-stroke. The pipe is 23 inches long. I have heard the recording of one and the sound was as pleasant to my ears as Tina Turner! I bought a Chinese "canister" from ebay for about £30 out of curiosity some years ago. Opened it up and there was nothing inside other than space. An airspray can with ends soldered on would have been just as good i.e. not effective at all.

I have a Toni Clark 2577 3-chamber silencer for the Zenoah 20/26 engines. It increases the power by 25% and reduces noise when the correct length is set for the header. Those with a sharp eye may notice that this is not a standard ZG26. It is one of Ralph Cunningham's creations. Ralph was the master of all things Zenoah in the US. He took a standard 26, removed the flywheel and in its place mounted the CH Ignitions PCB using the standard Zenoah ignition coil resulting in a lighter 26 but with the excellent CH Ignitions setup.

I wondered if a moderator would kindly add the word "Engine" after the word Petrol in the title so that it makes more sense. Thank you.

Paul - what sort of canister are you using in the video?

Try this link direbtly the you browser.

As we all know 2-stroke engines can be quite useful in large model aircraft but tend to be noisy and the noise is uncharasteristic of real airplanes. I love chainsaws but not in the air! When I was an active modeller learning to fly up to around 2010, I purchased a number of Zenoah and other 2-S engines and at the same time 2*MVVS tuned pipes designed for the MVVS 26 IFS and one of the zenoah tuned silencers designed for the Zenoah 20/26 engines. I had experienced the sound of a piped 2-S engine fitted to an LMA Greenly at our Bury St Edmunds RC Model Club and and fell in love with the low noise and the general un-objectionable character of the sound. Hence my purchase of one tuned setup for each of my 20-26cc engines. Due to work commitments the engines and the pipes were never run and have been sitting in a cupboard for the intervening years. Is anyone using tuned pipes/silencers with their 2-S petrol engines and would like to share their experiences?

You could try this site. http://www.model-plans.co.uk/KIT PLANS.htm at http://www.model-plans.co.uk/kamco.htm

In the UK V-Power Unleaded contains between 0% and 5% ethanol by volume. This is in the Shell specs for V-Power but they do not say exactly what is the actual percentage and whether it varies or on what basis. As to the use of Chinese carbs and repair kits, does no one ever wonder why it is that quite a few of the UK sellers of Chinese garden machinery provide a 2-year warranty on the machines but limit the warranty on carbs and bearings to 6 months by calling them "consumables". An example being ParkerBrand - a brand of which I have some experience. Yet the likes of Zenoah, Makita, Echo... with their Walbro or Zama carbs guarantee the whole machine including the carb for 5 years. Check out nearly new Chinese original chainsaws for sale on ebay and the reasons for them being listed as "For Parts or Spares". Ditto the number of suppliers of carbs for the GGP SV150/160/200 lawnmower engines on ebay. The float needles often fail to seal properly after 12 months and the carbs start leaking. My Briggs Quantum/IC engines on lawnmowers are still on their original carbs after 15+ years. One Quantum engine on a large walk-behind lawnmower is now 22 years old and still running as it did on day 1. All it gets is a filter and oil change every year. With Chinese original carbs performance is often rather hit and miss and longevity highly limited. This is of course just my experience and that of my local garden machinery shop where the owners have been servicing such machines for 40ish years.

I have quite a few items of garden machinery which are in regular (weekly) use during the summer months but not much during winter. My fuel of choice during the summer is Shall V-Power but towards the end of Autumn I switch to Alkyl based fuel (Aspen or equivalent) which can then sit in the machines over winter. I don't use E10 based petrol in my machines at all even though I'm quite happy to strip all types of carburettors, clean and replace the diaphragms etc. Also, when servicing Walbro/Zama or even Chinese equivalent carbs, I try to use genuine Walbro/Zama diaphragm kits as most aftermarket ones are rubbish and don't last.

Thank you for the welcome messages gentlemen. 🙂

Thanks for the welcome David. Being a bit of a nut about engines of all sorts - RC models, motorbikes, cars, even garden machinery - I used to follow the engine conversion chaps in the US modelling scene quite closely. Over there they had quite a few small engineering shops with CNC machinery wand the owners willing to convert engines for not much money as a hobby. The strimmer, chainsaw types engines were really popular a they were of very high quality, lasting many years, and made good power. Which is all engines like the Zenoah 38, 45 and 62 ever were. The cheap chinese engines killed off the business side of conversions but some still do it has a bobby. We didn't really have the equivalent workshops with CNC machines over here willing to do the work for little money. The converted four stroke petrols were really popular with the WW1 biplane contingent. Some still do the conversions - Stihl 4-Mix engines are quite popular these days especially the 62cc engine from the BR600 backpack blower. It produced the same sort of thrust as a Zenoah 62 so is capable of flying 1/3 scale biplanes and sounds just right for those models.

Hi David, yes it was. He either fitted a quiet extension to the front half of a standard 2S silencer or made one up from scratch as a complete unit for an extra £5. Mine was the latter type. I always thought that he must have been very skilled to be able to come up with soemthing so effective.

It feels like I must have been one of the few MDS owners who hit lucky. My MDS40 in a HMM Moonraker performed well but was a little noisy. I had a super-quiet silencer manufactured by a chap who used to advertise in the modelling magazines and it really quietened the engine down. With this silencer the MDS sounded like an engine with a quiet tuned pipe. It was a pretty powerful combination too. Having said that, the silencer did cost nearly the same as the MDS. Perhaps the comarades who manufactured it had been on the Vodka bottle on that particular day as it performed brilliantly. I still have it!

Hi John, Some photos as requested. As you can see the conversion involved removal of all the excess metal, machining and balancing the the flywheel and fitting of a CNC machined mount and prop hub. From memory the Honda GX35/25 and the Fuji EH035 received larger carbs of the same type as the original as part of the conversion. Honda GX35 (the intake filter cover will be removed and a trumpet installed when it goes into a model). The GX25 is physicall identical, just lower capacity and power. Fuji EH035 The Fuji is better suited to the Fokker DVII with its narrower front fuselage whereas the Honda with its round oil atomiser chamber is better suited to round cowl models.

Thank you. Yes - both the Honda engines are the ones sold on their strimmers/brushcutters. The Fuji and the Honda were very popular conversions in the US for Balsa USA's quarter scale kits. Their weight meant that none or little extra weight was need for balancing and they sounded just right in flight. All three were converted in the US and shipped here.

Here is a photograph of the Moonraker that I built in 1995. The experienced modeller who was my trainer commented on how smooth a flyer it was as a trainer and also highly areobatic when thrown around the sky. The power is from an MDS 40 with a super quiet custom made silencer. It proved a perfect combination. Another photo with the Moonraker being modelled by the memsahib. I still have the Moonraker although a bit dusty at the moment. I also have an unstarted HMM Chandelle kit and a Saito 72 to power it. The Chandelle was the larger 72" version of the HMM Vandetta aerobat. 🙂

I am sort of returning to the hobby and re-registering on this site after about 25 years by going through my two bedrooms full of "kits to be built when time permits", collection of unused aeroengines and part/fully built models. My introduction to aeromodelling happened in the early 1970s when watching a TV programme called "The Lad and the Giant" where the nasty giant put the 2-3 humans in a model aeroplace and flew it around the sky. From memory it was an original Super 60 controlled by a self-oscillating single valve Tx/Rx combination. But we had no money to indulge in such things so it lead to nothing other than endless dreaming. But I did start buying the odd RC magazine. I started learning to fly in 1995 when in employment with a J60 and then a HMM Moonraker. But work, which was a hobby in iteself, got in the way so I put the models away to be flown again when time permitted. I started again in about 2005 but once again the learning progress was overtaken by work. I did regularly pop into the olocal model shop, Galaxy Models of Ipswich, and buy kits as well as engines as a way of relieveing life's stresses (yes, it's not only women who go shopping to relieve stress!). Here we are, now nearly of pension age, going through my kits and engines this weekend. I did have some models built in the intervening years by a very experienced gentleman by the name of Norman who used to work at North-West model supplies in Wigan. So, here is a list of my collection of kits: Unstarted kits in boxes Flair Models: Atilla (2 off), Magnatilla, Hannibal, Puppeteer DB Sport & Scale: Major Mannock (one of the original kits I was fortunate to purchase from an elderly modeller many years ago) (cannot seem to find the Moth 40 and the Tigermoth 40 boxes but they'll be here somewhere) Balsa USA: Fokker Eindecker 90, Taube 40, Fokker D7 1/4-scale, Sopwith Pup 1/4-scale Bridi: Big Bee (96" w'span trainer/sport model from the US for Zenoah 38, 26, 45 etc. which is very similar to the LMA Greenly ) Ben Buckle: Radio Queen Svensen: Vicompte 1915 Howard Metcalfe Models : Chandelle Colibri 4ch (laser-cut cesena like trainer kit for 20-30 size 4-strokes) Thunder Tigre Pegasus 40 (72" w'span ARTF trainer/intermediate for 40-46 2s and 52-60 4s engines) VMAR Apache III 70" w'span ARTF trainer Plus a few IKARUS, Multiplex etc. slow flyers Part-built Kits D&B Sport & Scale: Bistormer 72 Ben Buckle Super 60 Galaxy Models Gazelle 4-ch trainer Flair Cub (4ch) Fully Built Models HMM Moonraker trainer with MDS40 and Super-quiet custom silencer (used in my learning to fly) VMAR Discovery trainer with OS FP40 and OS quiet silencer (used in my learning to fly) Radio Queen built with 4ch wing Powerhouse 82" oldtimer Flair Fokker DVII in full Lozenge pattern Oracover Unused Engines Zenoah: 20, 26, 38, 62 (all but the 38 converted to EI by Ralph Cunningham in the US) plus about four other 2-S petrol engines 4-stroke Pertrol Engines: Fuji 35cc for the Fokker DVII 1/4 scale, Honda 35cc for the 1/4 scale Pup and Honda 25cc conversion for the Hannibal Laser: 70, 100 OS: FS 26, 40*2,48*2, 61, 70, 80, 91 Saito: FS 45s*2, 72, 82 Thundertigre: FS-90 Enya: 43-4C, 60-4C SC: FS-30, 61 Used engines: few 4-s glow including a Laser 150 and a few 2-s glow Then there are the numerous DB Sport Scale Plan packs, plans etc. including plans purchased from the US Whilst going though my gear over the weekend, I felt like one of those baddies in their cave full of gold and jewels that one sees in films. This lot will probably keep me going for the rest of my life! Before anyone suspects, I am not a scammer and not trying to sell anything 🙂

I have a Hannibal kit (as well as Attila, Magnatilla and Puppeteer) in my collection of kits - the intention was to build them after taking early retirement form work. If you still need this or any other information, I can look it up for you.