marbleturtle

I was thinking about reducing the flutter issue while attempting to push to higher speeds.

... what does that V10 TDI weigh?

Well maybe... again! I have no quarrel with the fact that a large prop is going to be more efficient than one ducted fan with a fully exposed frontal area duct... roughly 5-10% in favor of the large prop in cruise conditions if each are fully optimized. What I am putting to paper to run through the numbers (eventually) is how 250HP driving a single pusher prop compares to 250HP driving two blended shrouded ducted fans (comparable surface area? I dunno yet). I'll see if I can draw a picture to show you what I mean. The whole idea started after looking at Mick Perry's site. Mick is quick to admit that his ducted fan design is slower than most long EZ's, but many of his problems are identified and curable: low engine power, duct to large, fan slightly too large, etc. The idea of forgoing a PSRU is attractive if I can get close to 95% the efficiency of a standard prop. Now if I just find my slide rule.

Side by side in the back... but not on nacelles. Jets need nacelles to get out of the boundary layer of air to reduce induction turbulence. Ducted fans can use the slower boundary layer for greater thrust generation. I was thinking of blending the shroud into the top of the strakes... this way only about 1/2 of ducting adds to the frontal area. Perry Mick's entire single duct (save a few small patches blocked by the strakes) is added frontal area. Keep in mind this is just theory I'm considering. Well... maybe. If you take a rotary spinning at high RPM (7500?), normally you attatch a PSRU and a large prop to move a large amount of air. I'm wondering if I can simplify things by using a direct shaft to a high RPM fan (7500?). This smaller fan would be accelerating less air faster. But I have now been thinking two fans! Can 2 small fans move as much air as one large prop? Our props are partially blocked by the fuselage. Fans on the strakes would have full front exposure. (?) Ducting blended into the strakes reduces some of the disadvantage of duct fans, namely the added frontal area of the duct. (?) This is starting to keep me up at night! The $64,000 question I'm working on is, can the small fans create as much or more Kinetic Energy by moving "less air faster" than the PSRU system moving "more air slower". I guess I've been looking at boats too long. Big giant paddle wheeler, pushes lots of water slow and more efficient. Direct drive little outboard propeller... pushes small amounts of water fast! no. no. Only when I reduce power and drop from 30,000 feet.

... it also covers me while I ride my 200mph motorcycle.

Well my problem will be 0 hours in type (unless you count Greg's jet Cozy in a few weeks) and training hours in a C172 (newbie pilot). I forgot to log my 4000 hours playing Flight Simulator and X plane! I could spend $4k getting my hours up over 100, but that won't help me in "type". If I had no assets to go after... I'd say screw it and continue. I'm covered on life insurance. All I want is the liability coverage. If I bash up the hull... I'll just build another (its faster the 2nd time around... right?). So I guess my question is... do you think am I going to be able to get liability with the rotary engine conversion or will I need to stick with a certified engine to have a better chance of getting insured? Say it ain't so!

Hey Chuck... I was thinking more along the line of composite canards! I knew the structure would be difficult to design, but I guess the aoa of the canard preventing main wing stall is the prevailing issue. You could limit the pivot, but that would reduce manuverability. Okay, that idea's out, but I'm still thinking about my twin duct fans!

Another old topic I'm sure... but things seem to be changing on a daily basis. Also I just read on John Slade's website that he is having problems getting insurance. So here goes... 1. What insurance is required? 2. Is it possible to get simple liability coverage (no hull) on an auto conversion engined experimental?

... it would be alot more stealthy if you didn't have that big heavy clunky hunk of air cooled metal hanging out the back!

HEY!!! Some of us do pretty well keeping the masses confused... thank you very much!

I was thinking about the design of the canard and the problem of elevator flutter... has anyone or any design used a solid rotating canard as the elevator? I'm certainly not going to try it, but it seems like it could be done similar to military aircraft where the entire horizontal stabilizer is an elevator. This is also done on the kit aircraft that was featured on Discovery Wings (forgot the brand). Just a thought...

You could try this... But may I suggest doggie ox is the least of your problems on a 4 hour flight? I for one don't want to look in back and go "EEEWWWWWWWWWWW"!!! doggieox2.bmp

Like most of you, I only plan on keeping the sunny side up! But it is interesting to learn about how the design works in different attitudes. Thanks again Wayne!

I think the archive could be useful if all of the "junk" is tossed. I certainly do my share of shooting the breeze on the forum, but if someone must search through anything and everything to find what they are looking for, the archive becomes useless. The aerobatics thread is a good example. If everything but the final threads posted by Wayne Hicks are thrown out, it's useful. If everything is kept, no one would bother reading through all the BS before getting to the 5th page where the REALLY good information is located. Someone running the forum needs to review what is kept and what is tossed. Otherwise we as posters would need to have some sort of checkbox to indicate whether or not our thread reply is to be archived... hoping that everyone would use it properly. My $0.02

... and count your blessings that you have your wife's support! My GIB is becoming a BOW about this. I say let the grass grow and hire someone to do the dishes! 7 years from now I want something other than a trim lawn to enjoy and be proud of.

<-- MCSE, MCSD, MCP+I, MCDBA... but believe it or not, I'm not a HUGE fan of Microsoft. Its just a matter of following the path of least resistance. 95%+ browsers are IE so it is not worth the extra time to develop for other browsers... especially since IE is free. Apple is the BetaMax of the VCR world. And if Apple would quit giving Steve Jobs a new jet or multi-million bonus when he comes up with something new, maybe he would stick around and develop enough products to present a serious challenge to the big M. Linux... pppbbbthththth! Open source code is a disaster waiting to happen when it comes to security. So that leaves a few million of us goose stepping to the tune of Microsoft until something better actually comes along. http://www.microsoft.com/learning/mcp/success/peters.asp

sweet! But you said you wanted to be able to adjust the engine while running... may I suggest that the blades blow into the engine so you are pushed away from the prop instead of getting sucked in?!?!?! If that Lycotranscontinentalsaurus is going to kill you, it should at least have the decency of doing it while providing the pleasure of flight!

... sounds dangerous. Why not bolt up a round table top and spare yourself a good beating?!?!?!

Rats! Automatic transmission... those are de-tuned and don't generate the HP of the manual transmission cars. Turbocharging it "shouldn't" be a problem, but if they made changes to the design like higher compression, it may be a problem. Not that I was going to pony up $4K for one... now a 20B might be a different story.

... I wonder how much trouble it would be to turbocharge that monkey.

hmmm... I think I'm covered on a rotary. But if your interested in a Lycoming, there are three engines on a bench at my local FBO waiting for their owners to refinance their homes to pay for the MO's. I bet you could buy any of them cheep!

I heard Nat say +10 G and -6 G... but that was airframe. I don't want to come near either one of those numbers!

I think I'm gonna use a big honkin pitched prop that I can't over-rev!

oh... I see what you mean. I never could follow directions without an explanation! I seem to remember something about fiberglass or carbon fiber hinges... anyone know a web site that has those?

... why not?!?!?!