Geoff_H

Has anyone experienced carburetor icing in a small aircraft engine. I am designing a small Cri Cri look alike and am considering putting cab heat to both engines. At present my thought are for wrapping carbs in insulated heating wire (final design very much unknown). But is this necessary, does anyone have carb heat on their small engine, very small aircraft?

In system's that must be reliable and isolated from any fault that may occur we use two diodes in parallel, their outputs connect together and each diode connects to the battery's. Hence if a system goes down for any reason the other diode instantly takes over. Use a similar reverse system for charging two batteries, but you must set the charging voltage 0.6 volts higher to account for the voltage loss through the diodes. But with the ignition power you must put a monitoring system to monitor each stage to each diode otherwise one might fail and you will never know until the second system fails. These techniques are used in control systems that must work, eg driverless trains etc. Their probability of failure is very low,. Their mean time between failures is in the millions of hours.

I thought that it was just not a good idea as one does not know what is in the drum for certain. If it has not been stored upside down it is a definite water ingress kit like the GA refuelers use. Better to be on the ground wishing you were in the air than in the air wishing you were on the ground. Water in fuel could bring about the later.

Electrical power in the poles and wires from the power station to your local transformer that is. I spent 42 years in this industry. We always crimped.

A properly done crimp joint will have a galvanic connection pressure greater than 30,000 psi. Above the pressure at which oxygen can infiltrate and cause corrosion and high resistance. But it must be done properly, an improperly done joint will cause problems and as most people don't have a crimping tool that ensures that the crimp is compete before letting go then the heat shrink with solder would be better, but I would not use it. All connections of electrical power are crimped and bolted, never soldered owing to long term degradation of solder.

Sure this is the mechanism of final failure, a soldered joint is ridgid and has little support which increases the stress on the copper that is held at the sharp soldered joint. A crimped joint is allowed to flex with less stress where the copper leaves the shroud. Hence crimpping gives a better life, provided a crimp is done correctly with the proper tool, one should never use pliars or similar. The cable is actually held by the insulation and the copper is galvanically crimped but does not carry the wire load.

Wires that have been soldered will fatigue and break, maybe the wire was soldered to a lug. Ensure that all wires have crimped fittings. This is a rule for GA aircraft LAMES. Cheers Geoff

I think that it is more a ground effect machine. besides increased thrust in ground effect it will balance the craft by giving more thrust to a side that should dip down. Notice that one engine is upside down, maybe for gyroscope and air flow torque effect equalisation. What happens when an engine fails? mmmmm

Hi Ron and welcome to these interesting pages. Rave you read the Wikipedia on BD5 history? They are fast and unforgiving, a bit like the Mooney I owned for some years only giving it up last year as I now am building a fibreglass Cri Cri similar aircraft. The aim for this aircraft is under $10k. I am on track with the price and have the engines, foam and wheels brakes etc. The engines are two Hirth single cylinder engines. But the reason for telling you this is that I have a Cozy IV partially finished that I started and stopped when I bought the Mooney for the outback work I was doing. Being retired I will never have the money to finish it and the wife will not fly anymore so it is not needed. I would like to finish it but only to sell it and I would rather concentrate on the Cri Cri style aircraft with aerobatics etc. I do not know what engines you intend to use in the BD5 but I would suggest a water cooled two stroke engine, the are so much more difficult to seize. I have had a rough running Lycoming from chilling the engine. I think that it is best that you look at water cooling being a very low time pilot, it is more difficult to destroy a water cooled engine as a low time pilot. I can assist with a Hirth engine if you are interested (I must declare an interest as I am a Hirth agent in Australia). Cheers Geoff

Blue Max oil is a premium oil recommended for Two Stroke engines, Hirth engines in particular, from Hirth website: "Typical benefits you can expect when using BlueMax 100:1 oil: Less smoke Ratios to 100:1 Less oily mess from the exhaust system Engine life increased 100% mineral based,none of the unfavorable attributes of synthetic oil, no solvents added as in 50:1 oils Less carbon build up than 50:1 oils" So you use less oil. It is expensive, I have not investigated the shipping costs of oil but I expect that they would be expensive too. I guess that it would be over $25/litre plus GST and that is with very little profit margin for the effort. I personally believe that it is not worth the effort. Anyone got any thoughts on this?

We had a Piper Cherokee fly over our driveway at the time of the Google earth picture, it looked like the aircraft was in my driveway, amazing since that was where I was building a small aircraft.

We have recently been made the Australian re-seller for Hirth Engines. We are trying to make a list of Hirth engines in Aus so that we can provide specialized support for these engines and gearboxes. If you have a Hirth engine and have not let us know what engine you have please drop us a reply here or email [email protected].

Hi all, my name is Geoff and my small company has become a reseller for Hirth. I am a professional mechanical engineer and consultant for big Engines and power systems. I do not know what Hirth Engines are in Australia but will stock spares if I can determine what Engines we have here. I can also visit groups around Aus with a few small Engines that we have in stock. I love to chat aviation so call me anytime, I have been in GA for 35 years and have owned two aircraft and am building an experimental aircraft. Our website is still in its infancy and will be modified and added to over the next few months. www.Hirth-engines.com.au