John Minchell

Thanks Tore - that's very useful, I had not spotted that on the PS site before.

Thanks Frank - will take a look. The spare tuned pipes I have were in with the deal when I bought a S/H Zenoah 80cc twin. They are KS 40cc to 50cc size so should be ok if I can make up a header/ manifold.

Anyone know if the Zenoah 45cc petrol engine responds well to a tuned pipe instead of a cannister type silencer? I need to quieten it down from the standard oblong box with the two exhaust outlets and have already got a spare 40 to 50cc KS pipe on the shelf. Is it ok to use this rather than buying a silencer can, will it make the engine more peaky or wear it out quicker - and will it need re-tuning on the fast and slow needles? Any help appreciated.

The more oil in the methanol or petrol / oil mix, the weaker you are running the engine at the same fuel consumption rate. Maybe why you needed to run it "rich" so that it actually wasn't running lean - assuming that none of the oil was being burnt. A common missunderstanding some two stroke motorcycle racers had back in the day, more oil means leaner mixture so needs bigger carb jets for the same correct combustion.

I can put up with the petrol smell due to the ridiculous price of Aspen fuel. Between 4 and 6 times the price of supermarket pump petrol looking at ebay & local Aspen stockists.

Good point Frank - and with two tugs in the car.......................the stink would be twice as bad! I feel a turning session on the lathe coming up for two nice knurled edge ally pipe bungs.

Thanks chaps - three pipe set up and I have a new felt covered clunk (petrol) for the carb feed line and will make the filler pipe able to empty as well with a short length at the front of the tank and close it off for flight use just leaving the breather line open.

How do you empty the tank if you haven't run it dry when the clunk is direct plumbed to the carb? The filler only pipe stops just past the bung and the vent to the top of the tank. Does a second clunk need to be fitted just for emptying?

We have a reccomendation but not a rule that no one can fly solo - beginner or experienced from a safety point of view. But then we are flying models on one of the busiest live full size airfield's in the country - Sleap in Shropshire. It has its compensations though - aerobatic Pitts Specials and Slingsby Firefly, Bucker Jungmann and Jungmeister, Avro Anson and two WW2 Yak fighters, a taxi rated Jet Provost and all manner of light general aviation aircraft. Always something to watch while you have a coffee between flights. No beginner can fly without supervision till they pass the A cert.

Matt Carlton As far as spectators are concerned at the scale nats, I suggested you contacted Chris Allen as I was not sure about spectators. You haven't, so I did, and the situation is as follows:- BMFA Members are allowed as long as they abide by the Buckminster site rules. There will not be roped off areas - ie don't wander about on the flightline or runways when competitors are flying or about to fly - etc. List of visitor protocols on the Buckminster website. Non BMFA Spectators - situation and entry fee, if allowed, still under discussion. As far as using alternative RAF sites to Barkston - I am informed that all outside agencies (BMFA and us modellers) are not allowed to use any RAF facilities till further notice & C19 pandemic is over. So that would preclude using any other airfield until life is back to normal, at which point we will probably be allowed to use Barkston again.

Don't think so, but for clarification please email contest director Chris Allen on [email protected]

The Scale Nationals will be held at Buckminster on August 14th & 15th for RC, CL and FF. STC are just working out the details over the next couple of weeks.

One thing I have heard of (over on another stick and tissue forum - HPA) is that 1/16 balsa sheets can be cut using multiple passes on a silhouette cameo to make all the rib or former parts for small lightweight rubber or CO2 models. Opens up the possibility of all those old Keil Kraft and Veron flying scale models to be made from decent wood and your own accurate parts set if the kit isn't remade by VMC or another laser cutting outfit. John M

Thanks all - enough there for me to figure something out.

What is the usual fuel tank size people put in their models for say a 40, a 60 and a 120 size glow 2 stroke to give enough time for a full schedule and a bit spare for an aborted landing and go around again? John M

Steve It definately is not an Algebra, fuselage on the wooden one (800 or 1000) is totally different (rolled Ply) and the tailplane is all moving and sited 1/4 way up the fin from solid 3/8" balsa sheet not built up. Otherwise Algebras has sheeted foam wings and glass moulded fuselages. John M

Denis, all models which are competition ones or have a large bill attached, will not be using a Bec ESC or a stand alone UBEC like this one. They will all have separate Rx supply battery and the main power LiPo will only get used for the motor. I will now only trust Becs in cheap foamys and maybe F5RES 2/3 channel glider etc. I wasn't advovating cutting off all the heatshrink - only a section at both ends to allow airflow through, but maintaining the electrical insulation.

Thanks for the replies guys - the jumper is indeed on the 5.5v pair of selector pins and was always in that position in use, as I have some servos which are only 6.0v capable as well as the HV ones that the UBEC took out. My MPX Rx is safe to 12v but receiving 25v was too much. The fingered heat sink is totally covered by the heatshrink plastic as supplied - preventing any through airflow and there is substantial carbon dust and "ash" type residue on the inside of the heatshrink which is where the component blew and failed. I am now better educated and will take a scalpel to all ESC's heatshrink that I am using the BEC on to power the radio and allow air flow through the fins inside the heatshrink or across the plate type of heatsink. Whether overheating was the cause of this one blowing I will never know, but nothing got overly hot (I checked with a temprerature sensor under the canopy and there are fuselage inlet and outlet airflow holes) as the climb was 30 to 45 seconds or so followed by gliding for up to 30 minutes on the task. And of course the UBEC was powering the Rx servos for the whole flight.

I had a 4 Max 20amp UBEC installed in my large Valenta Thermik XXXL 5m electric soarer for GPS Triangle racing. I wanted to save the weight of a separate Rx / servo battery and this looked like a good option, without relying on the BEC in the ESC which would not handle the 10 servos in the model. It was fine for about a dozen flights, but has now failed. Instead of failing and not passing any power through, it failed and passed the full 6 cell LiPo voltage (25v fully charged) through to the Rx and servos. It has unfortunately fried my RX12 DR Pro Multiplex dual receiver (£260) and taken out the two digital servos in the fin (£100+), fortunately I did not have the wing attatched with another 8 servos in it. The specs of the UBEC are 3 to 12 LiPo input and 20amp output (8 to 12 servos). I have spoken with George at 4 Max about it and he says it is the first one he has heard of which has failed. I just wanted to advise anyone using this unit to keep an eye on it and check its output before connecting it and risking an expensive model or equipment. Or to do as I will now do and carry the weight of an additional Rx/servo battery. In closing I have a number of other 4 Max products and they are performing ok, so this is extremely disappointing and expensive when you are on a tight budget. Pics show failed component after I removed the heatshrink covering. John M

Hi Don - no it wasn't me, but I have a good mate who is sending me a new, unrun ASP 120 with silencer for £50. I thought that was more sensible than a used and possibly abused engine from ebay. Thanks for your help. John

Thanks Don - dunno what I'll do yet, it depends on what motor I can find at the right price etc. As I say I have a brand new in box Super Tigre 2500,but it's way too heavy. As long as a good 120 or 108 2T will fly the model, then hopefully I can find something cheap but a good runner.

Thanks Don - gives me something to go on. What size & pitch prop does the ASP 120 turn? John M

I have a 72" span Maxim model which used to fly with a 20cc fourstroke glow motor - YS / Yamada or something. I aquired the model without servos or motor. I wanted to put a spare ST2500 in it but with 6x standard 60g servos and a motor weight of 1.2kg it will put the OA weight to 5.3/5.35kg which is over the limit for your UKCAA competitions. Does anyone know the weight of say a 120 ASP or SC or some such similar 20cc 2 stroke motor (with and without silencer) which I can get hold of easily (money is tight too, so likely second hand) and with some 30g servos I can squeak under the 5kg limit? TIA John M

I thought the Solarfilm company had stopped trading? John M

Colin I spoke with Paul and he has seen your email - he's rushed off his feet with Xmas sales stuff but will reply to you as soon as he can. John M