bugatti P100 flies....then has a minor oops

[RHB785]

G'day Adam. I also think that 2X200 hp engines is a bit lame but maybe that's what was available and affordable at the time. The Pond racer had a pair of V6 Nissan engines of about 3 litres each and they developed over 450 hp each, admittedly at much higher revs than the original straight 8 Bugatti engines in the original aircraft but with today's techology and materials it should be possible to make a gear box system that could handle the higher revs of a modern owerful engine. However, that may break the budget so I guess they've gone with what they can afford for now. Maybe a some later stage they'll be able to afford to increase the power by fitting different engines. I wouldn't advocate the 300Z engines of the Pond racer which were putting out 600 hp but were notoriously unreliable. Perhaps if they were only putting 450 hp they may have been more reliable than they were. And yes, that 1930s flight control "computer" still has me intriqued. The only thing I can think of is that it was some kind of mechanical mixer similar to what the Mirage had.

Regards,
RHB.

[Adam the Akrodude]

Hey Ross

Yes, perhaps they are making baby steps and starting with lower horsepower whilst investigating the lower speed regime of the flight envelope. I would love to see this aeroplane with higher performance engines in the future to see if it can in fact reach 500mph+! I guess the issue is finding engines light enough and small enough. The liquid cooled V-6 engines just may be too heavy?

My background and current work is with industrial instrumentation & control, hence the interest in what they've mentioned in terms of flight control - is it some kind of computer controlled electro-mechanical system. This is a small aeroplane so whatever they've used must be simple and light. Tell me about the Mirage "mixer" - you have me intrigued sir!

A mate of mine is ex-RAAF (gunnie) and he did not enjoy working on the Mirage during his time at ARDU. Very crammed fuselage that required some very convoluted arm manoeuvres to reach for whatever he needed to get to in the fuselage. I'm guessing it must have been "fun" working on electrics on the Mirage huh?

[RHB785]

G'day Adam. I'm not so sure that the original engines were so light. To the best of my knowledge they were standard straight eight Bugatti car engines which in those days were probably not as light as a modern alloy V6 and remember that the Bugatti engines were also liquid cooled. The intake and outlet to this system was "drag neutral". In other words the outlet provided enough thrust to equal the intake drag. I have read about the Bugatti quite some years ago and I was amazed that this could have been achieved with the technology of those days. The article I read back then also explained the "flight control computer", but I now can't remember that aspect of this amazing aircraft. I've tried today to search without success for information on this system. I think it was some form of mechanical device similar to the Mirage's mixer.

As to the "mixer" in the Mirage, to the best of my recollection it was a form of parallelogram linkage under the cockpit floor which moved according to the control stick inputs to it. Pull the stick back and both sides of the parallelogram moved together. Push the stick forward and the same happened but in the opposite sense. Move the stick to the left and the parallelogram moved in an asymmetric manner. Move the stick to the right and it moved in the same manner but in the opposite sense and so on when the stick was moved to make a climbing or descending turn the same happened in a proportinal sense. To do a normal turn say to the left the pilot rolled the aircraft onto its left side and then pulled the stick back, at least that's my recollection from a few rides in the simulator at Williamtown. Perhaps Ray S could correct me if my memory is incorrect but that's how I remember it.

Regards,
RHB.

[oz rb fan]

with a little devopment the hyabusa engines can put out pretty good power(well over 200 hp)...and the type 50p engine put out around 250 hp(buggered where WIKI got the idea of 450 ho each)

[RHB785]

Hi Adam. Your ex gunnie mate was right about how difficult the Mirage was to work on. They took the biggest most powerful engine they could find and stuck it into the smallest fuselage they could draw on the drawing board and crammed everything else in around the engine. There were indeed jobs you had to do strictly by feel because you couldn't see anything in the tiny panel they gave you to work through. Changing an aircon duct sensor in a single seater was a nightmare. The canopy had to come off and the seat had to come out and the LHS console side panel had to come off. It was a minimum 4 hours job. The same job in the two seater was five minutes; literally. Open the baggage compartment door in the LHS of the nose and the sensor was right in front of your nose; literally. All the aircon and pressurisation gear was in the nose of the dual because it had no radar. Doing a generator or alternator change on either was a nightmare. Changing the battery in a single was easy; in a dual a nightmare. Yet I still have a lot of affection for the old Miracle. She really was a lady. A bit fickle sometimes and oh so French but a lady nonetheless. Here I go again. Major thread drift alert.

Regards,
RHB.

[Adam the Akrodude]

I bet that the site owner will have absolutely no issue with this thread drift! As one of the site moderators, I'm 100% all for thread drift like this. It would be a major case of the pot calling the kettle black in any case, as I am sure I have a reputation for thread drift posts in the past . It's all part of the flow in the conversation. Hey, both the Bugatti and Mirage fly (we can say this now!) and are French, so it's not too far off the original post.

Anyone say over 45+ years old who has done drafting (the old fashioned kind on a drafting board with pencils, fine ink pens, etc) will know what a French Curve is. It's a stencil/template for drawing complex curves. Some French aircraft are down right ugly, but when the French get it right, they get it right - Bugatti and Mirage are classic examples and heavy use of French Curves in the drafting office, which would have been "de rigueur"!

The Brit's even managed to find a French Curve in their drafting office when drawing up the Concorde's ogival wing!



Under the loose heading of beautiful wing shapes (not too much of a drift, as it involves aerodynamic beauty), how are these for some seriously beautiful French Curve inspired wings!















And arguably the most famous of ogival "double deltas" - the Space Shuttles wing design. Without a doubt the most aerodynamically and thermodynamically wing ever put to use.

[Adam the Akrodude]

with a little devopment the hyabusa engines can put out pretty good power(well over 200 hp)...and the type 50p engine put out around 250 hp(buggered where WIKI got the idea of 450 ho each)

The EAA site has the engines @450 HP each. Makes sense if 500+ mph was the aim. This isn't a light aeroplane either at almost 1.5 tonne. To go fast you need a lot of ponies as we all know (oh yeah plus money!). Damn drag going up at the square of speed! So, 900HP kind of sounds right to me to achieve 500mph. I'm not expert in Bugatti's but a quick search shows the 50B engine at around 400HP for the racing car. A bit more boost (lower engine life) could bring this up to 450 HP I guess.

Still I wonder whether they may be able to reach 300+ mph - should be possible with 400+ HP overall you'd think. Issue will be tip speed of the prop's and keeping this subsonic. These are small diameter, high revving prop's so tip speed must be an issue at high RPM.

[RHB785]

And don't forget the MiG 21 Analogue Adam. The beautiful Mig-21 based aircraft used to test the Tu-144's wing shape in airborne tests.

Regards,
RHB.