Geoff_H

The cri cri can take off and fly on one engine. With props 600mm diameter and engined 400mm off centre it is engine out simple. Tail surfaces are comparatively large, it is an aerobatic aircraft.

Hi Kasper, thanks but I would have to single engine it. RAA are unable to accommodate two engines. A recent attempt to register one totally failed. The aircraft has Junkers flaperons has a large speed range. What about the beauratic stuff? Are construction inspections required?

Thanks Nev. Stall speed full flaps expected approx 35knots

I have been building a CriCri similar aircraft for some years. As it has two engines and CASA (unlike the original designer, UK an French authorities) says it is a twin in its behaviour even though it's two engines are just over 24 inches apart. The endorsement will cost me $5k to $10k. RAA can't seem to accommodate a twin engined aircraft. So I have thought of changingind the engines to a single. Question is what inspection etc are required by RAA to register the craft? What are the costs? I know I have to get an RAA licence....never really understood why, I learned on C150 and still fly them on occassions. But what other problems am I likely to encounter as it is a composite design very much unlike a cri cri, only the aerodynamics are similar.

I feel the same about Mooney aircraft☺️

I learned to fly at Cooronbong. A large part was in a 150 Aerobat.

The electricity grid was sold off to get money for making tollways toe sell etc. I worked on a Victorian Power Station control system upgrade circa 2000. At that time the SECV (Victorian state owned power authority) for a very large amount of money, in fact they overpaid by about 100%. The Company that bought it quickly realised that they had overpaid and let the industry know. Seeing how much money that Victoria had got ever other state in Australia tried to sell their power system, but the industry had woken to the little money that they would make and were not interested. So to be able to sell the NSW system a Poles and wires upgrade was initiated. A few future possible use substations were built but the Poles and Wires (all very reliable) campaign was stated, a huge increase in the cost of electricity was then applied, we all groaned but paid it. These new rates changed the profit margin that an authority could make. The industry flocked to buy it. They are making a mint. My data from 2019 was that electricity bulk average rate was $0.14c/kwh, most us pay around $0.33c/kwh. Ok there are expenses but that is a nice profit for using computers to buy and sell electricity. The sale of the NSW electricity commission was essentiall an ongoing pseudo tax on NSW residents courtesy of the politicians. Similar to Tollways etc. When I bought my Cherokee in 1983 I just paid an Air Navigation Charge (the name may have been different as my memory is not good). For that charge I got all my government landings, documents and administration for free. Now everything costs way more than it costs them so that they can return money to government coffers. Airports given by the government to local governments quite often saw the real estate being sold to fill the local government coffers, more often than not wasted.

https://avdata.com.au/airport-charge-rates this gives charges that need to be paid through avdata.

It is the area that the "fly neighbourly" in ERSA asks you not to fly. Not that I would ever go against the request.

Some years ago I just flew over and thenw by Ayres Rock. It had the radio operator all confused. He thought that I was landing, told him I could not afford it for so limited gain. I also got to see why there is a fly unneighbourly area. Mmmmmmm.

I believe that the problem that we have with CASA is the way it is set up. For the safety of the airways! A public servant responsible for anything is a hopeless situation. They will overprotect their backsides without any wish to get meaningful operations. One situation I know of is with Cri Cri aircraft, lighter than most RAA aircraft but with 2 200cc engines, two foot diameter props puts the engines very close together. In most countries they are regarded as single engine, engine out is very simple, even the designer makes that statement. CASA has refused to make this allowance. Why help some people, they just protect their ass.

The thing that surprised me was the response about Blackhawk aircraft from CASA. I was told, by a helicopter rebuild place, was that the reason that any aircraft that has been in a war zone cannot carry passengers because there was no certainty as to maintenance or out of boundary stresses from abnormal flying. Maybe I was not told the facts, but the CASA management seemed to not have a clue as to what CASA was actually doing. No real surprises for me. The medical guy was on the ball though. Maybe he should head CASA.

Very interested. Please continue to show progress. Cheers Geoff

It is just the mechanical protection. Thermal protection provided by the insulation. Insulation glued to firewall for structural support. I really don't care if you don't believe the facts. I know Cozy use it from over 30 years ago. I have written the last on this.

It seems like you doubt it?

It is only a carrier of the thermal barrier. The barrier is also glued to the bulkhead ( special high temperature glue). The aluminium is essentially mechanical protection. Definitely used in aircraft.

Used in many composite aircraft. Titan developed it and promotes it.

Proven system.

Why use steel? Heat conductivity of 45w/mK and weight of 7.6k kg/M3. When Aluminium 1/3 the weight and back the aluminium with 13mm Fiberfrax heat conductivity of 0.22w/mK and weight of 96kg/M3 so much lighter so much more (approx 250times) more heat insulation. A longer time before your plywood bulkhead starts to smolder and fill the cabin with smoke. It is also a driven system.

I suggest that you look at GA designs and copy one of them. That way you could fail to some nuance but overall you will probably get the best result. I would not copy a RAA nor an amateur built aircraft. Their designs have a high degree of problems. One of the things that worried me is the high proportions of plastic fuel lines that I have seen. I am designing and building a composite Cri Cri aerodynamic similar aircraft. I have found that it is extremely time consuming with very little previous designs to call upon, I have to research so much and end up making something similar that has been previously designed. It has worn me down and I am seriously looking at abandoning the prokect. I have had 40 years of designing and trouble shooting mechanical equipment, I also have a degree in mechanical engineering. To get it right on your own is possible but what if you get it wrong? What design review process do you use? How do you make sure that the reviewer is doing a good job. I worked for a company in Dallas that did nuclear design ( not me). They put the checker in a room, no telephones, no other personally allows in, max checking time without break was one hour. What I am trying to say is don't do your own thing, use the greater knowledge of the professional flying community, unless you have professional training, even then consult other very experienced people.

Aluminium and fiberfrax is far lighter and approximately same cost as Stainless. Aircraft Spruce sell it probably cheaper than stainless. A special high temperature glue is used. It will also be infinitely slower to heat whatever is behind the firewall

At the end of the day ( a strange statement lol,) a firewall is about limiting the temperature rise of the cockpit side of the firewall. An interesting one is for the CozyIV. It uses aluminium, light but conducts heat rather well, coupled with fiberfrax, a sheet of "stuff" that is a very good insulator of high temperature heat and is very light. I saw a demonstration of this stuff over 30 years ago, thin blanket of fiberfrax one side a hand the other an oxytorch! Impressive! But I was told that it's low temperature heat conduction characteristics are not so good.

I have never done an airflow through the engine but I think that the Reynolds number varies with fluid density, would these values and assumption be true for both sea level and 10,000ft? No idea just asking

After 40 years of designing constructing and commissioning I have learned that any errors in design and the working end product depends upon the accuracy of your assumptions. The best advice is to do your calcs three times. Once where you expect assumptions to be then do them twice with assumptions at their extremes. The results will be the worst possible outcomes. I was the lead engineer in the middle east in the early 90's. It was an American job and back in Dallas we had PhD people check all of our calculation in a multiday seminar. They were good calcs. Got the design running in Syria, it didn't work as expected. After a lengthy investigation we discovered that our assumptions were wrong! We did modify the plant and it eventually worked to spec. Ever since I question assumptions not the calcs (not as much anyway). Murphy was an optimist. My long held saying. Geoff

If I remember correctly you can use Reynolds number to calculate friction in pipes etc then use a circuit diagram for the airflow and solve it as if it were am electrical circuit.